Heavy Metals

Effects of heavy metals and xenobiotic chemicals on benthic fauna

In the 1960s, heavy metals were widely regarded as the most serious pollutants affecting the marine environment, although this may have been the result of a greater perceived understanding of these and the development of widely available atomic absorption spectrophotometers (and the fact that we were not yet aware of persistent synthetic organic micropollutants). Monitoring programmes that measured concentrations of heavy metals in fish and shellfish were developed alongside international initiatives such as the OSPAR Commission which aimed to control pollutants respectively from vessels and land-based sources (entering the north-east Atlantic area). One of the best was a programme called the Global Mussel Watch. Concentrations of metals in seawater are difficult to monitor because they are low, even in contaminated areas, and vary greatly both spatially and temporally. Hence it was agreed to use mussels (such as the ubiquitous blue mussel Mytilis edulis) which concentrates metals and...

Heavy Metals

Lower plants, algae, and especially fungi, are superior to higher plants in coping with heavy metals. In general metals are deposited on surfaces. A particular type of crust formation is the so-called desert varnish that is formed by biological activity. Rock inhabiting algae and fungi solubilise iron and manganese ions from the rocks and deposit them on the surface. The advantage of the crustaceous life form on rocks (mostly dolomite) is a higher C02 concentration, and a prolonged water availability after dewfall Rocks absorb dew by capillary action. This moisture is sufficient for net C02 assimilation by endolithic lichens. Cliff drawings, close to Avdat, Negev, showing a rider on an ostrich hunt ostriches were extinct in the Negev a long time ago. Cobbett C, Goldsbrough P (2002) Phytochela-tins and metallothioneins roles in heavy metal detoxification and homeostasis. Annu Rev Plant Biol 53 159-182 Heavy metals are metallic elements with a density 5 g cm3, namely the elements Ag,...

Toxic heavy metals

Many heavy metals such as arsenic, lead, cadmium, mercury and copper are naturally present in seawater at very low concentrations reflecting their low solubility (see Table 4.3). Various organisms need some of these in very small amounts, for normal metabolism. However, increased concentrations resulting from pollution may be harmful both to marine organisms and to humans. The concentration of heavy metals in the water may be raised locally by discharges from many industrial processes, and in sediments they may become very high. Sewage sludge dumping provides a significant input. Metals may also be released into the water from sediments disturbed by dredging, or by changes in pH or redox potential. Many marine organisms concentrate heavy metals and it appears that this increases their tolerance to even greater concentrations. Certain metals, such as copper, are essential for normal enzyme activity but may become enzyme inhibitors at high concentrations. Except for the Minamata tragedy...

Alien Species and Contemporary Evolution

The example of late blight of potatoes is only one of many cases in which alien species pose threats to human interests through their evolutionary potential. Strong anthropogenic selection pressures imposed by pesticides, antibiotics, and environmental pollutants such as heavy metals have long been known to induce resistance in plants, animals, and microbes. Numerous plants have shown rapid evolution of resistance to heavy metals in spoil heaps associated with mining activity (Macnair 1987). Literally hundreds of plants, animals, and disease organisms, many of them alien to the regions involved, have evolved resistance to pesticides (see, e.g., National Academy of Science 1986). More than 100 plants now show resistance to herbicides, with more being recorded annually.

Deposition of Gases Controlled by Stomatal Resistance

Sulfur and nitrogen dioxides are very important gases with regard to the acidification of the environment and related environmental effects, including mobilization of toxic heavy metals in the aquatic ecosystems. Therefore, the deposition of these two gases, as precursors of acidification, have been intensively studied in both the laboratory and field measurements. It was concluded that the deposition of SO2 onto short vegetation is determined largely by stomata uptake within a small rate of deposition onto external surfaces. This deposition has a diurnal cycle with the maximum occurring in daytime and a nocturnal minimum. Deposition of SO2 to forest is further complicated by the emission of reduced sulfur compounds. Thus, it can be concluded that the rates of SO2 deposition are controlled mainly by the chemistry at the vegetation-atmosphere interface and that, as the surfaces are wet most of the time, the processes are regulated by the chemistry of this thin film of moisture. Many...

Transport and Reconcentration of Metal Ions

The metals which are of most environmental concern are first transition series and post transition metals (Figure 2.8), many of which are in widespread use in industry. Often, the non-specific term 'heavy metals' is used for three of the metals, namely lead, cadmium and mercury. These have large bioconcentration factors in marine organisms (look at the values for lead and cadmium in Table 2.1), are highly toxic and, unlike many of the transition elements, have no known natural biological functions.

Detection And Purification Of Biochemical Compounds

Immunoassay uses antibodies to form a precipitate with specific compounds. Antibodies are special proteins produced by the body to bind with foreign substances so that they can be made harmless. Each antibody is highly specific, binding only to a single substance and binding extremely tightly in what is called a lock-and-key relationship. Molecular biology techniques have enabled the production of large quantities of antibodies of a specific type, called monoclonal antibodies. They are used for research purposes as well as to detect specific hormones in pregnancy tests and tests for prostate cancer. Immunoassay is a highly sensitive and selective detection method. Its use has been extended to organic pollutants and even to heavy metals.

Low surfacetovolume ratio mucilaginous forms

Provided colonies have a simultaneous capacity for controlled motility, there are good tele-ological grounds for deducing circumstances when massive provision of mucilage represents a discrete and alternative adaptation to a plank-tic existence. However, the idea that streamlining is more than a fortuitous benefit is challenged by the many non-motile species that exist as mucilaginous colonies. There are other demonstrable benefits from a mucilaginous exterior, including defence against fungal attack, grazers, digestion or metal toxicity, and there are circumstances in which it might assist in the sequestration or storage of nutrients or in protecting cells from an excessively oxidative environment (see Box 6.1, p. 271). Even mucilage itself, essentially a matrix of hygroscopic carbohydrate polymers immobilising relatively large amounts of water, is highly variable in its consistency, intraspecifi-cally as well as interspecifically.

Environmental Risk Assessment

It is well known that biogeochemical cycling is a universal feature of the biosphere, which provides its sustainability against anthropogenic loads, such as acid forming compounds of S and N species, heavy metals and persistent organic pollutants (POPs). Using biogeochemical principles, the concept of 'critical loads' (CLs) has been firstly developed in order to calculate the deposition levels at which effects of acidifying air pollutants start to occur. A UN ECE (United Nations Economic Committee of Europe) working group on sulfur and nitrogen oxides under long range transboundary air pollution (LRTAP) convention has defined the critical load on an ecosystem as ''A quantitative estimate of an exposure to one or more pollutants below which significant harmful effects on specified sensitive elements of the environment do not occur according to present knowledge.'' These critical load values may be also characterized as ''the maximum input of pollutants (sulfur, nitrogen, heavy metals,...

Biomonitoring See bioassay

Bioremediation The use of living organisms to break down pollutants or wastes, such as industrial effluents, mining spoil, or oil spills, and to restore contaminated ecosystems. Plants may be used (phy-toremediation) to extract heavy metals from contaminated soils and water. Some crop species can be genetically modified to accumulate toxic ions, e.g. Arabidopsis has been altered to express the enzyme mercuric ion reductase, which converts Hg2+ to Hg, which is volatilized and released into the atmosphere. Uptake may also be assisted by the use of chemical chelating agents to immobilize the toxins. Contaminated water is treated by rhizofiltration using plants with high transpiration rates and extensive root systems, such as willows (Salix) or reeds (Phragmites), or by the use of aquatic plants that are removed and destroyed once they have extracted the toxins. Organic wastes are usually tackled by bacteria and protozoans, and occasionally fungi (certain fungi are capable of breaking...

Heavymetal sites and their vegetation in Europe Evolution and distribution of metallophytes

After the last Quaternary Ice Age, forest developed on nearly all soils in Europe, except on those with extreme climatic or edaphic conditions. In the latter group are soils with elevated concentrations of heavy metals, too toxic for trees. In such situations, shadow-sensitive xerophytes were able to survive when they had the genetic advantages in metal tolerance (Ernst et al. 1992). Heavy-metal-tolerant vegetation was originally restricted to natural outcrops of metal ores, scattered as a relic of the Late Glacial epoch over Europe. Most of these habitats were destroyed or modified by mining activities from the Bronze Age onwards. However, metal mining has considerably enlarged the potential habitat range by creating further areas of metal-contaminated soils (Ernst 1990 Ernst et al. 2004). In Europe, sparsely distributed sites with metal-enriched soils form residual sanctuaries for metallophyte communities. Most sites are disconnected spatially and are of very limited extent. The UK...

Franka Dicotyledon Symbiosis

The aerobic Gram-positive actinomycetes belonging to the genus Frankia are diazotrophic bacteria that are capable of inducing formation of N2-fixing nodule lobes in roots of many dicotyledonous angiosperms. The plants nodulated by Frankia strains are known as actinorhizal plants and include 8 families, 24 genera, and over 200 species, most of which are perennial woody shrubs or trees distributed in all landmasses except Antarctica. The actinorhizal plants share a predilection for marginally fertile soils and the majority are pioneers on nitrogen-poor sites. In addition, many actinorhizal species are able to tolerate environmental stresses such as heavy metals, high salinity, drought, cold, and extreme pH. They inhabit a variety of ecosystems, including coastal dunes, riparian zones, alpine communities, arctic tundra,

Time Scale of Plant Response to Environment

We define stress as an environmental factor that reduces the rate of some physiological process (e.g., growth or photosynthesis) below the maximum rate that the plant could otherwise sustain. Stresses can be generated by abiotic and or biotic processes. Examples of stress include low nitrogen availability, heavy metals, high salinity, and shading by neighboring plants. The immediate response of the plant to stress is a reduction in performance (Fig. 3). Plants compensate for the detrimental effects of stress through many mechanisms that operate over different time scales, depending on the nature of the stress and the physiological processes that are affected. Together, these compensatory responses enable the plant to maintain a relatively constant rate of physiological processes despite occurrence of stresses that periodically reduce performance. If a plant is going to be successful in a stressful environment, then there must be some degree of stress resistance. Mechanisms of

Types of heavymetal sites

Tertiary alluvial habitats are more of a natural kind and are generally species-rich, because they originate as a result of metal loadings to well-developed soils in riverine systems, often close to primary and early secondary sites (Van der Ent 2007). Downstream of mining activities, riverbanks have been flooded with metal-enriched materials and seeds of metallophytes since the Middle Ages in the Tyne valley, England (Macklin & Smith 1990), in the Innerste and Oker valley in Germany (Libbert 1930 Ernst 1974 Ernst et al. 2004) and in the Geul valley in the Netherlands (Kurris & Pagnier 1925). Due to leaching of heavy metals from the surface soils, the survival of this alluvial heavy-metal vegetation type depends on irregular metal replenishment by incidental riverbank flooding, such as in the Tyne valley in 1986 (Rodwell et al. 2007), and in the Innerste and Oker Valley in 1969 (Ernst 1974) and 2007 (Klein & Niemann 2007). These heavy-metal-enriched sediments not only affect...

Classification of European metallophyte vegetation

The heavy-metal content of soil is one of the most important edaphic factors determining vegetation composition. Heavy-metal toxicity of the soil, as well as low nutrient status, poorly developed soil structure and often water-restricted conditions maintain open vegetation, retarding succession. Many sites also harbour important populations of rare bryophytes, lichens and insects in addition to metallophytes. Being immobile, plants can survive only by adapting their physiological processes, and because metal tolerance is so specific, eco-types of plants are restricted to individual sites, so-called 'local endemism'.

Classification of metallophytes

(1a) Obligate metallophytes species with an exceptional tolerance to heavy metals in soils as well as a dependence upon the occurrence of these metals in soil. Some are also hyper-metal-accumulators ('hyperaccumulators'). They are not found outside this narrow ecological amplitude within the same phytogeographical area. These species are local endemics with sometimes a large geographical distribution. Examples are Alyssum pintodasilvae (Dudley 1986), Viola guestphalica and V. lutea subsp. calaminaria (Hildebrandt et al. 2006 Bizoux & Mahy 2007). (2a) Associated metal-tolerant species matrix species that are associated with the related plant association with a large ecological amplitude. They are either called 'pseudo-metallophytes' or 'accompanying species' of the true metallo-phyte vegetation. These species are moderately tolerant of heavy metals in soil, but not dependent on their presence. Examples of such species which are both common and have a wide geographic distribution are...

The Structure of the Book

The processes up to the level of an entire canopy, demonstrating that processes at the level of a canopy are not necessarily the sum of what happens in single leaves, due to the effects of the surrounding leaves (Chapter 5). Chapter 6 discusses mineral nutrition and the numerous ways in which plants cope with soils with low nutrient availability or toxic metal concentrations (e.g., sodium, aluminum, heavy metals). These first chapters emphasize those aspects that help us to analyze ecological problems. Moreover, they provide a sound basis for later chapters in the book that deal with a higher level of integration.

Effects On Surface Water

Acid precipitation causes many observable, as well as nonobservable, effects on aquatic ecosystems. Included are changes in water chemistry and aquatic faunal and floral species. One reason for changes in surface water chemistry is the release of metals from stream or lake sediments. For example, Wright and Gjessing (1976) note that concentrations of aluminum, manganese, and other heavy metals are higher in acid lakes due to enhanced mobilization of these elements in acidified areas.

Steadystate Modeling the Effectiveness of Abatement Measures

The overview as obtained by accounting will rarely describe an equilibrium situation. In the economy as well as in the environment some stocks are building up while others decrease. Disequilibrium implies that the magnitude of flows and stocks, even with a constant management regime, is sure to change. Steady-state modeling aims at calculating the equilibrium situation belonging to a (hypothetical) substance management regime. It is not a prediction of a future situation. The result of steady-state modeling may instead be regarded as a caricature of the present management regime, not blurred by the buffering of stocks. It is therefore most suitable for comparisons between management regimes. In Chapter 30, a steady-state model is applied to the case of heavy metals to assess whether the present regime is sustainable. A comparison is made between the present management regime and a number of others, containing different sets of abatement measures. Static and steady-state models have...

Willow Systems with Zero Discharge

CW system based on willows has been developed as a sewage disposal solution in rural areas in Denmark (Figure 33). Main attributes of the willow wastewater cleaning facilities are that the systems have zero discharge of water (because of evapotranspiration) and part of the nutrients can be recycled via the willow biomass. Furthermore, the harvested biomass may be used as a source of bioenergy. One-third of the willows are harvested every year to keep the willows in a young and healthy state with high transpiration rates (Figure 34). The stems of the willows are harvested on a regular basis to stimulate the growth of the willows and to remove some nutrients and heavy metals.

Ecophysiology of metallophytes

As established by Mendelian genetics, the number of genes necessary for tolerance to cadmium, copper and zinc per se are two for each element, with many modifiers determining the degree of metal tolerance (Broker 1963 Macnair et al. 1993 Schat et al. 1996 Bert et al. 2003). In addition to any prevailing metal toxicities, metallophytes have also to adapt to other extreme chemical and physical soil factors (Baker 1987), such as dry soils, by structurally enhanced proline levels (Schat et al. 1997), differences in calcium status (Zhao et al. 2002), iron availability (Lombi et al. 2002) and sulphur supply (needed to synthesise adequate amounts of metal-binding compounds) (Ernst et al. 2008). The low availability of the major nutrients nitrogen and phosphorus (Ernst 1974), characteristic of open oligotrophic environments, requires metal-tolerant plants to evolve a high degree of major nutrient efficiency, especially on secondary and most tertiary metal-enriched sites. Heavy-metal-resistant...

Effects of acidity on stream ecosystems

The degree of acidification is of course very important, and depends upon both inputs and buffering capacity. Organisms evidently are harmed via diverse pathways, including metal toxicity, and taxa differ in their susceptibility. Consequently, while one can assert that anthropogenic acidification is generally harmful once pH falls much below 5.0, the details depend upon many factors.

Raw Material Substitution

Typical examples are the substitution of high-sulfur coal with low-sulfur coal in power plants. This substitution requires little technological change but results in a substantial pollution reduction. Changing to a fuel like natural gas or nuclear energy can eliminate all sulfur emissions as well as those of particulates and heavy metals. However, natural gas is more expensive and difficult to ship and store than coal, and many people prefer the known risks of coal pollution than the unknown risks of nuclear power. Coal gasification also greatly reduces sulfur emissions. Another example is substituting gasoline with ethanol or oxy

Effects of Heavy Metal Pollution

Some heavy metals tend to accumulate in the soil, due to their high affinity both with soil organic matter and with mineral particles. This accumulation eventually exceeds the toxicity threshold tolerable by soil microorganisms and soil fauna - the major drivers of the decomposition process. The direct effect of heavy metal accumulation on plant uptake depends on soil properties - soils with neutral pH and high clay content can immobilize large amounts of heavy metals, while the chemical composition of leaves is not significantly affected by the heavy metals in the soil. However, plants growing on these soils are only temporarily protected against heavy metals until the soil retention potential for these metals is reached. In acidic soils, the low pH increases the solubility of most heavy metals leading to the uptake of heavy metals by vegetation, and to their accumulation in the plant tissues (e.g., leaves). Because all heavy metals are potentially toxic, there is some concern about...

Case Histories And Ecosystem Surveys

The sources of many environmental contaminants are relatively easy to identify. While shortlived contaminants are most readily identified close to the source, the more persistent substances, such as heavy metals and PCBs, may achieve a truly global distribution due to atmospheric transport and deposition to soils and surface waters. The interim period between emission or discharge of an environmental contaminant and ultimate contact with a specific ecosystem or representative species often contains many varied and interesting processes. Harrison, Harrad, and Lead (Chapter 31) describe some of the more important processes involved in pollutant transport and removal from the environment and discuss how such processes influence the distribution of pollutants. Included are processes leading to the transfer of chemical substances between environmental compartments such as water to air and air to soil. Bioaccumulation and bioconcentration are terms describing the transfer of contaminants...

Issues in Dose Response Relationship in Ecological Risk Assessment

Different concentrations of the heavy metals in sewage is an example of attempts to develop stressor dose-response relationship as an indirect approach for assessing the bioavailability of nickel to humans via ingestion of plants grown in such a soil. However, a stressor dose-response relationship established in this case addresses several tox-icological issues. First, the microbial activities measured are meant to assess the effects of the heavy metals on the microbial population as well as plant uptake of nitrogen through the activity of nitrogen-fixing bacteria that may be present in the soil. The data obtained can be used to determine the level of ecological toxicity (ED50) for guiding decision on heavy metal-laden sewage disposed in farmlands. The foregoing indicates that except clear-cut objectives that are established from the onset of an ecological risk assessment, the outcome may be of little or no practical use. Ecological stressor dose-response has often been applied to the...

Metabolism An Ecological Model of Society

Substances normally buried deep with the Earth's crust can be extracted, refined, and introduced into the biosphere at quantities that ecosystems are not able to assimilate. Examples include heavy metals, radioactive elements, minerals, and mined carbon. Because there are few natural cycles that can return these substances to the crust within human time spans, these substances systematically accumulate in the biosphere.

Wastewater Characteristics

Sure of the organics present in the water, determined by measuring the oxygen necessary to biostabilize the organ-ics (the oxygen equivalent of the biodegradable organics present). Inorganic chemical parameters include salinity, hardness, pH, acidity, alkalinity, iron, manganese, chlorides, sulfates, sulfides, heavy metals (mercury, lead, chromium, copper, and zinc), nitrogen (organic, ammonia, nitrite, and nitrate), and phosphorus. Bacteriological parameters include coliforms, fecal coliforms, specific pathogens, and viruses.

Components of the Edaphic Factor

The second reason is that plants obtain most of their water from soil and the amount of dissolved ions in soil water can influence a plant's ability to take up water (see the following section). The influence of pH on ion availability stems primarily from the influence of pH on the solubility of the various compounds present in the soil. In general, soil compounds containing some elements are more soluble at some pH values than others. For example, iron is relatively insoluble at pH values of 8 or greater and plants with a high iron requirement may perform poorly in soils with high pH values. Similarly, many heavy metals become increasingly available for plant uptake at pH values of 4-5. Thus, plants growing in low pH soils are more susceptible to heavy metal toxicities.

Plant Life on Selected Edaphic Conditions

Unusual edaphic conditions harbor unique plant associations often characterized by rarity and endemism. Such conditions also foster distinct morphological and physiological modifications leading to characteristic plant communities. One of the most remarkable edaphic habitats in which such unique plant communities are found is on serpentine soils derived from ultramafic and related rocks (i.e., rocks high in iron and magnesium silicates). Ultramafic rocks such as serpentinite and their associated serpentine soils are found throughout the world, concentrated, however, along continental margins and in regions of orogenesis (i.e., mountain building). Serpentine soils are unique in that they are often high in pH and heavy metals such as magnesium, nickel, and chromium, and generally low in essential nutrients, Ca Mg ratio, and water-holding capacity. The rocks are often on open, steep slopes exposed to high light and heat conditions, and resulting soils are generally shallow and highly...

Wastewater Discharge Standards

Effluent limitations can be technology-based or water quality-based, with the former considering BPT, best available technology economically achievable (BAT), best conventional pollutant control technology (BCT), or new source performance standards (NSPSs). BPT emphasizes end-of-pipe controls and reflects the average of the best for the industry category it deals primarily with conventional pollutants such as BOD, oil and grease, solids, pH, and some metals. BAT can include pollution prevention through process control and end-of-pipe technology it deals primarily with toxics such as organics and heavy metals. BCT is used with BAT. NSPSs are based on the best available demonstrated control technology (BADCT) it is typically similar to BAT with BCT.

Examples of Endocrine Disruption

Both deliberately and inadvertently into consumer products. With regard to long-range transport, large masses of air have been tracked across the Pacific carrying a variety of pollutants from central Asia to the west coast of the US virtually undiluted, including ozone, heavy metals, and organochlorine compounds. In addition, so-called 'global distillation' processes - repeated sequences of volatilization and condensation - transport semivolatile compounds from sites of production, use, and disposal to colder regions, particularly at high latitude and altitude. The accumulation of vast amounts of plastic products in the oceans is yet another source of global pollution, due to leaching of endocrine disrupting chemicals from plastic.

General responses of macroinvertebrates to metal pollution

Studies of urban runoff identified metal-tolerant (Zn and Ni) families as including Hydrophilidae, Asellidae, Ephemerellidae, Philoptamidae and Chloroperlidae with metal-sensitive families being Leptophlebiidae, Ephemer-idae, Leuctridae and Hydrobiidae (Beasley & Kneale 2003). Chloroperlidae, however, were reported to be absent in the presence of Acid Mine Drainage (AMD) in rivers in the Iberian Peninsula (Garcia Criado et al. 1999), although Leptophlebiidae were also absent. This variation in response is sometimes noted in the literature and may be due to added effects of different metals and acidity (see later section on metal toxicity). In addition, many authors have identified the high degree of variation in the response of families and genera to metals and acidity (Gower et al. 1994 Hickey & Golding 2002 Hirst et al. 2002 Beasley & Kneale 2003 Gray & Delaney 2008), which makes it extremely important to identify to species level when monitoring responses of macro-invertebrate...

Earthworms phylum Annelida Clitellata Oligochaeta

Digestion of cellulose and chitin is normally attributed to endosymbiont activity. There is a gland in the upper intestine, the organ of Marren with chloragocytes, which contributes to the removal of ingested calcium and other abundant cations. These are precipitated as calcite and other crystals by a locally increased acidity. The crystals are excreted with the undigested remains of digestion. It is an important function, because ingestion of clays and plant matter can increase mineral concentrations to pathogenic levels, if they are all absorbed. The gland also has functions similar to the vertebrate liver, in that it supports blood detoxification and stores glycogen. The chlorago-cytes also contribute to removal of heavy metals (Jamieson, 1981).

Direct toxicity of metals

Toxicity within organisms only occurs when the rate of metal uptake exceeds the combined rate of excretion and detoxification of the metabolically available form of the metal (Rainbow 2002). The effects of metals on organisms can range from those which are undetectable, through sub-lethal to lethal. Mechanisms of metal toxicity are mainly linked to biochemical reactions involving

Data And Methodological Issues

A final methodological issue relates to the quality of output flows, and their potential impacts on the environment. As mentioned earlier, all flows cause change, and depending on their character and mode of release these changes can be local or widespread. Output flows of heavy metals and persistent organic materials clearly have different potential impacts from earth that has been merely moved from one place to another. However, depending on the perspective of different individuals, both can be important. Merely summing up all flows as if they are equally important, without carefully clarifying important distinctions, can therefore be rightly criticized. Output flows were characterized according to five quality categories in Matthews (et al. 2000), based on nature of the flow, and whether it had been processed or not. However, as an illustration of the complexity of evaluating the potential impacts resulting from output flows, manure from animals, considered to be in the...

Detecting Evolutionary Changes to Stressors

Evolutionary responses to pollutants have been less widely documented than responses to pesticides. Nevertheless, there are now well-studied cases of plant species evolving in response to waste from mining operations. Plant populations growing close to smelters commonly show a much higher level of resistance to heavy metals than other populations. The evolution of pollution tolerance has also been demonstrated in aquatic fauna, including crayfish, worms, and midges. However not all plants or animals successfully evolve in response to pollutants levels of biodiversity are often much lower in

Uptake and bioaccumulation of metals

The uptake of high concentrations of metals by macroinvertebrates is likely to result in direct toxicity, and therefore some groups may be preferentially removed in impacted streams. For example, collector-browsers and collector-filterers showed a significant reduction in response to elevated levels of Cu and Zn (Hickey & Golding 2002). Survivorship of juvenile amphipods was also found to be significantly reduced when fed on copper contaminated diets, and reduced feeding was also observed in adults (Roberts et al. 2006). In contrast, some authors have suggested that there is no specific evidence for toxicity even where metals are accumulated within invertebrates (Borgmann et al. 2007). This is because heavy metals can be stored in organisms as non-toxic species or bound to metallothionein (Gerhardt 1993). De Schamplherlaere et al. (2004) demonstrated that, although dietary copper was effectively taken up by Daphnia magna, this caused an increase in reproduction and growth which was...

Losses and Gains of Eco Exergy by Human Activities Included Pollution

When contaminants, for instance heavy metals, are widely dispersed, eco-exergy is lost. When leaded gasoline was used to obtain a higher octane number, on the order of 400 0001 of lead were dispersed annually around the globe. Lead was even found in the ice pack of Greenland A typical concentration in lead ore is about 5 or 0.05 kgkg_1ore, while a typical concentration in the environment after the dispersion is 1 mgkg 1 soil. If we presume 300 K, the annual eco-exergy lost can be found by eqn 7 as

Importance of sediments

Experiments conducted in field situations revealed that once iron-coated rocks were placed in a clean environment desorption of sulphate occurred from the precipitates, and this resulted in destabilisation of oxyhydroxides enough to release them from the rock surface (DeNicol & Stapleton 2002). The release of fine flocculated precipitate was thought to have a much greater impact upon the fauna than the adhering precipitate, which was not directly toxic. The dispersal and deposition of sediments, therefore, can affect metal toxicity temporally (Besser et al. 2009). This has important implications in remediation as once the source of contamination is removed the accumulated iron precipitates on the sediments will no longer be in equilibrium with the aqueous environment and, thus, could be a potential source of metals to the environment (DeNicol & Stapleton 2002). If we return to the question of the Water Framework Directive, this legislation requires that surface waters should be of...

Metal and Metalloid Transformations

Metals and their compounds interact with fungi in various ways depending on the metal species, organism and environment, while fungal metabolism also influences metal speciation and mobility. Many metals are essential for life, for example, Na, K, Cu, Zn, Co, Ca, Mg, Mn, and Fe, but all can exert toxicity when present above certain threshold concentrations. Other metals, for example, Cs, Al, Cd, Hg, and Pb, have no known biological function but all can be accumulated by fungi. Metal toxicity is affected by environmental conditions and the chemical behavior of the particular metal species in question. Despite apparent toxicity, many fungi survive, grow, and flourish in apparently metal-polluted locations and a variety of mechanisms, both active and incidental, contribute to tolerance. Fungi have many properties which influence metal toxicity including the production of metal-binding proteins, organic and inorganic precipitation, active transport

Fungal Symbioses in Mineral Transformations

One of the most remarkable adaptations of fungi for exploitation of the terrestrial environment is their ability to form mutualistic partnerships with plants (mycorrhi-zas) and algae or cyanobacteria (lichens). Symbiotic fungi are provided with carbon by the photosynthetic partners (photobionts), while the fungi may protect the symbiosis from harsh environmental conditions (e.g., desiccation and metal toxicity), increase the absorptive area, and provide increased access to mineral nutrients.

Response Models in Ecotoxicology

Figure 5.6 shows the relationship between the concentration of heavy metal in animal tissues and in sediment. Such a simple models can be used to find concentrations of heavy metals of benthic animals in new sites. The same relationship can be seen in the data reported in Fig. 5.7 these data are more spread than those of

PH Adjusting Chemicals

Case I shows the occurrence of minimum solubility or maximum solids precipitation at optimum pH value. Typical wastes producing this type of response include iron contained in acid mine drainage and fluoride and arsenic-bearing wastes. Case II shows a neutral or acidic waste containing certain heavy metals. The optimum pH is at the knee of the precipitated solids generation curve. Lime treatment of metal finishing waste is typical of a Case II response. Case III is the inverse of Case II the chemical pollutant is precipitated due to pH depression, usually with sulfu-ric acid. A latex-bearing waste is typical of a Case III response.

Industrial Ecology In The Context Of The Uk

Recently, the UK Office for National Statistics' work on environmental accounts began to include a physical accounting for the UK's foreign trade activities (Vaze 1998). Further, at the Manchester School of Geography, the minerals and fossil fuels fraction of the UK industrial metabolism has been linked to geomorphological, environmental and land use change (Douglas and Lawson 2000). The Manchester approach explicitly deals with mobilized materials not intended to enter the economic process, including overburden from mining or translocated materials. These large hidden flows in industrial metabolism, consisting of mainly trouble-free materials (see Steurer 1996) are discussed in comparison to flows which are mobilized by ecosystems dynamics and recognized as problems from the point of view of sustainability. Furthermore, city metabolism for Manchester has been studied following a historical perspective (Douglas, Hodgson and Lawson forthcoming, see also Chapter 28). Projects with a...

Threshold and Nonthreshold Agents

Nonthreshold agents are a number of heavy metals, pesticides, and a number of toxic organic compounds. It is important to determine the noneffect level or noneffect concentration for these compounds to determine at which level or concentration a negative effect on organisms and ecosystems can be expected.

General effects of disturbance and their reproductive consequences

Fragmentation, (2) fire, (3) selective plant harvesting (e.g., selective logging), (4) introduction of herbivores (e.g., cattle, defoliating insects), (5) introduction of plants (e.g., crops, invasive plants), and (6) chemical disturbance (e.g., contamination with heavy metals, use of pesticides and herbicides). We did not include global-scale disturbances, such as climate change, because their pollination impacts are probably subtle and long term. We recognize that many of the disturbances listed above can be interrelated (e.g., fire may cause habitat fragmentation, or habitat fragmentation could foster invasion of aliens), but they have distinctive impacts on landscapes and individual plant features and so can be studied in isolation.

Mathematical Model of Gene Transfer in a Biofilm

Plasmids, small circular strands of DNA separate from the main genome of the organism, are common in natural bacterial populations such as soils, lakes and stream and in the gut of mammals. They often carry genes for such beneficial factors as resistence to antibiotics and heavy metals, the ability to ferment sugars, or to produce toxins. Some carry genes for pili production and mating pair formation that allow the infectious transfer of the plasmid to other bacteria - a process called conjugation. However, many plasmids have no known function in bacteria and may simply be parasitic. Vertical transmission of plasmids occurs during cell division when the plasmids in the cell are duplicated and partitioned among the daughter cells rarely, however, one daughter cell may end up without plasmid while the other daughter cell receives multiple copies. This loss of plasmid is referred to a segregative loss. Furthermore, there is some cost to an organism carrying plasmids since the cell may...

Early biomonitoring techniques

Whilst most biomonitoring techniques were developed based on the response of invertebrates, other biological groups were incorporated into some systems. In the USA, Patrick et al. (1954) developed a methodology based on the structure of diatom assemblages, and European workers developed ideas from the saprobic system using algae (Kelly 1998). The Quality Rating System (also known as the 'Q-Value' system), which has been in use in the Republic of Ireland since 1970 (Flanagan & Toner 1972), uses a combination of benthic algae, macrophytes and invertebrates. As well as having different sensitivities to toxins (particularly herbicides, but also acidity, heavy metals and other pollutants), phototrophs respond readily to nutrient pollution (Kelly 1998 Holmes et al. 1999) and, thus, are better capable of detecting nutrient impacts than invertebrates where any effect is indirect via the effects on phototrophs. At the other end of the food web, fish are particularly sensitive to organic and...

The natural history of edaphic specialization

In many cases, lineages that have evolved tolerance to one edaphic extreme have also adapted to other extreme factors. For example, tolerance of multiple populations to four elements (copper, nickel, zinc and lead) was assessed (Gregory and Bradshaw 1965) in Agrostis tenuis. Although most populations occur on pasture soils that have trace levels of heavy metals and comprise plants that are not tolerant of heavy metal contamination, mine tailing populations variously display tolerance to zinc, copper and lead, generally matching their tolerance to levels present in soils at the collection locality (Gregory and Bradshaw 1965). The authors also demonstrated that tolerance of each of these metals did not confer tolerance to the others, indicating somewhat distinct mechanisms in each case. Still, that this species has evolved tolerance to normally toxic levels of multiple ions suggest that an underlying trait, perhaps involving tolerance of low pH (Gregory and Bradshaw 1965), drought...

Environmental aspects

Plastic sheeting plays a very important role in water and vapour-proofing of conventional buildings. Durability is therefore a decisive factor. According to existing documentation it is unlikely that plastic products have these qualities to the desired extent. In terms of pollution, products made of polyethylene and polypropylene are unproblem-atic in the user phase. Sheeting and membranes made of polyvinyl chloride can contain softeners (phthalates) and other volatile additives that can cause problems if exposed in the indoor air. In waterproofing membranes for bathrooms, residues of bisphenol A and phosphates of lead have been documented. Products of polyvinyl chloride also often contain the potent heavy metals cadmium or lead as a stabilizer against ultraviolet radiation. Heavy metals are also commonly used in flashings and gutters made of polyvinyl chloride.

Knowledge transfer new indices and uncertainty

Due to its comprehensive nature, covering a wide range of water body types and biological quality elements, the WFD has precipitated an unprecedented development of new bioassessment tools across the EU. This process of development has benefited greatly from the knowledge gained through existing tools such as RIVPACS. Correspondingly, existing tools have been enhanced further to deal with the issues raised by the WFD. Following the move towards the sustainable use of water resources, many new indices are being developed for pressures other than sewage pollution, including, for the first time, indices to assess pollutants from primarily industrial sources. Examples include pH, heavy metals, thermal pollution and pesticides, the consequences of industrial and intensive agricultural processes. Rather than relying on expert judgement, as had been done previously (e.g., BMWP), new objective statistical techniques, such as artificial intelligence (e.g., Walley & O'Conner 2001) and partial...

Jeroen B Guine and Ester van der Voet

Heavy metals are key issues in environmental policy and management. Environmental problems related to heavy metals have a long history. Heavy metals, despite the fact that some metals are essential elements, have toxic properties leading to adverse effects on human and ecosystem health even in small doses. Another problem-causing property is their non-degradability once they enter the environment they will remain there for a long time. Metals tend to accumulate in soils and sediments, with real immobilization due only to geological, and therefore extremely slow, processes. Accumulation in the food chain may lead to an increased stock in biota, thereby magnifying the human dose. Present policies regarding heavy metals include not only end-of-pipe emission reduction but also recycling and even more source-oriented measures limiting or banning certain applications altogether (for example, bans on lead in gasoline in various countries). It is generally felt that the main problems have...

Health Considerations

The fate of heavy metal pollutants (such as iron, cobalt, nickel, copper, and zinc) in soils is not known, but their chemistry indicates that they generally form insoluble precipitates. The major mechanism for the retention of heavy metals in soil may be sorption on hydrous oxides of iron and manganese, thus significantly retarding the migration of these pollutants in the soil. As the capacity of soil to retain heavy metal elements is exceeded, a breakthrough to the groundwater occurs, and environmental engineers must consider this possibility when planning a permanent lagoon or landfill disposal facility.

Historical and Current Applications

Microcosms continue to be widely used for general ecological studies. However, in recent times, they have also become popular tools to study the fate and effects of contaminants (e.g., heavy metals), pesticides and herbicides, stressors (e.g., high temperatures), novel compounds, and genetically engineered organisms (Figure 1). They provide a comparatively safe means of assessing likely effects on ecosystems without direct exposure to the natural environment. Microcosms are not yet routinely used in ecotoxicological testing despite a strong argument from proponents that single-species tests are inadequate for full evaluation of ecosystem-level impacts. The problems with microcosm use relative to ecotoxico-logical single species tests include the higher costs, time involved, complexity, variability and difficulty in evaluating endpoints. Despite these issues, F. B. Taub and colleagues have worked to develop a standardized (nearly gnotobiotic) aquatic microcosm. This is now registered...

Perspectives For Sustainable Heavymetal Management In Agrosystems

Changing tillage practices may influence the stratification of pH, organic matter and metals. Moreover, cultivars may be changed and acid soils may be limed to increase the pH (see, for example, McLaughlin et al., 1994, 1995). Long-term strategies focus on reducing inputs to soils. This results in the steady state being reached with lower total accumulation and lower output rates. Input reduction can be achieved by reducing the amount of heavy metals in source material (quality) and by reducing the amount of fertilizer or manure added to the soil (quantity). This kind of input reduction could be aimed at by decreasing application (for example, by educating farmers on how to use nutrient and heavy-metal balances) or by changing the production system (for example, to a mixed farming system).

Nitrogen Toxicity in Aquatic Ecosystems

Mollusks (snails, clams), arthropods (crustaceans, crayfish), and amphibians are particularly vulnerable to a pH drop to below 5. Direct negative effects of low pH on fish reproductive rate and survival rates occur, but reduced availability of their food source (crayfish and insects) also has an indirect negative effect on populations of numerous fish species. Increased acidification of aquatic environments results, as for terrestrial ecosystems, in increased solubility of metal ions such as Al34 and trace metals (Cd, Cu, Pb, and Zn). This can cause direct metal toxicity to organisms both in the sediment and in the water. Increased Al34 concentrations can also reduce phosphate availability and disrupt P cycling. Acidification via acid rain, heavy metal toxicity

Polychlorinated biphenyl

Water pollution and soil pollution is caused by dissolved chemicals, suspended particulates, and floating substances, such as oil. Such pollutants include substances that are biodegradable, such as sewage effluent and nitrates leached from agricultural land, which if allowed to enter water courses can lead to eutrophication and algal blooms. Nonbiodegradable pollutants, such as certain chlorinated hydrocarbon pesticides (e.g. DDT) and heavy metals, such as lead, copper, and zinc in some industrial effluents, accumulate in the environment. Heavy metals, even when present at low concentrations, are toxic to plants, inhibiting water or nutrient uptake, damaging cell membranes, and inhibiting enzymes. Soil contaminated with fuel ash may contain increased levels of boron, which at high concentrations causes chlorosis and necrosis to tissues. Soil contaminated with mining waste may have high levels of copper, which damages root cell membranes and inhibits growth. Any contamination leading...

Onsite Chemical Surveys

Water in the field with a pH meter and use the results of these measurements to characterize the subsurface environment or classify the corrosivity of waste materials. They can also electrometrically measure the Eh of groundwater in the field using a platinum electrode and a reference electrode (Holm, George, and Barcelona 1986 Ritchey 1986). Then, they can use the results of the measurements to characterize oxidation-reduction conditions in the subsurface and evaluate the potential for mobility of heavy metals in groundwater.

Slurry Biodegradation

The technology, however, is less effective for contaminants with low biodegradability. In addition, the presence of chlorides or heavy metals as well as some pesticides and herbicides in the soil can reduce the effectiveness of the process by inhibiting the microbial action.

Phytoremediation and Other Biotechnologies

Compounds taken up, rapidly sorbed, or precipitated by roots (rhizofiltration) and young shoots (blastofiltration) or sorbed to fungi, algae, and bacteria (biosorption mainly to cell walls involving electrostatic attraction and formation of complexes). Marine algae possess large quantities of biopolymers (polysaccharides, uronic acids, and especially sulfated polysaccharides) that bind heavy metals. 10-60 dry weight of plant may be accumulated metals Contaminants taken up with water by cation pumps, absorption, and other mechanisms and usually translocated above ground. Harvested shoots or roots put in hazardous waste landfills or could be smelted after volume reduction by incineration or composting. Hyperaccumulation is approximately 100 times normal plant accumulation of elements and is 0.01 by dry weight for Cd and other rare elements, 0.1 for most heavy metals, and 1 for Fe, Mn, and other common elements

Chief routes of entry of marine pollutants

Many pollutants reach the sea either through direct drainage from coastal towns and industries or indirectly via rivers. Dilute industrial effluents, treated sewage and cooling water are often discharged into rivers and estuaries. Fertilizers, pesticides and animal wastes may drain into rivers from agricultural land. Huge amounts of silt resulting from rainforest clearance are carried down to the sea by tropical rivers. Rainwater runoff from cities and towns carries oil, heavy metals and other material into rivers. A surprising area of sea-bed around domestic sewage outfall pipes is often contaminated with oil (Dipper, pers. obs.).

Analysis of Pollution Data

When considering the significance of runoff pollutant contributions, both concentrations and total loadings must be examined. Receiving water concentrations are usually of prime concern. In principle, if pollutant concentrations do not exceed certain allowable maxima, detrimental effects will not occur. However, for many pollutants, allowable concentrations in water are not known. Because of sedimentation, accumulation of benthal deposits such as phosphorous, hydrocarbons, and heavy metals may be more significant than concentrations in the water. Receiving water column concentration and benthal accumulation depends more on mass loads of pollutants than of pollutant concentrations in the runoff.

Read and answer the following questions

By 1970 the problems of the environment had become international in scope. The oceans were seriously polluted, and no single country could control the situation. Pesticides and other toxic materials spread by air and water currents throughout the world were causing environmental damage everywhere. It was necessary to control the use of radioactive materials, heavy metals, toxic pesticides, or the dumping of petroleum at sea, and to regulate the exploitation of marine resources. But such control and regulations were ineffective without international authority.

Air Pollution Control

Different types of pollutants require different control devices scrubbers and condensers for acid gases, scrubbers and condensers with electrostatic precipitators (ESPs) or fabric filters (baghouses) for particulates and other heavy metals and chemical neutralization systems for oxides of nitrogen (see Sections 5.18-22). Variations exist within these basic categories while some devices are more likely than others to achieve high removal efficiencies, operational factors, such as temperature, play a key role.

Radioactive pollution

Seaweeds can concentrate radioiodine with great rapidity and fish absorb a variety of radioactive substances. In addition radioactive substances can bioaccumulate in marine animals in a similar way to heavy metals. The effects on marine organisms are not fully understood but may include genetic disturbances and increased mortality both in young stages and in adults. Interestingly, many marine invertebrates can withstand radiation doses that would kill people. Some deep-water marine shrimps, exposed to doses of natural radiation sufficient to debilitate people, remain unharmed. A variety of cancers in humans, such as childhood leukaemia, is linked to radiation exposure.

Turnover and Elimination of Radioactive Contaminants

Radioecological studies to gain a better understanding of the cycling patterns and rates of non-nuclear contaminants such as heavy metals or chlorinated hydrocarbons in these same organisms in the same natural habitats. In these cases radioecological study has proved to be able to contribute to a better understanding of environmental toxicology in general. This is particularly true in those cases where it is the basic movement and or behavior of the organism itself which is the critical factor in determining the uptake, concentration, or elimination of the contaminants from the system in question whether these contaminants are nuclear or non-nuclear in character.

Plastic and aluminium windows and doors

Many aluminium and PVC window frames are assembled in situ and likely to fall to pieces when removed. But both plastic and aluminium windows can be re-used if they are initially installed for easy dismantling. Pure aluminium windows can be material-recycled. This is unlikely for the other products, as they all contain complex combinations of different materials. Waste has to be deposited at special tips. From combustion of PVC dioxins and heavy metals can be emitted. Special care for disposal of the ash must be exercised.

Location Restrictions

Leachate is water that contacts the waste material. It can contain high concentrations of COD, BOD, nutrients, heavy metals, and trace organics. Regulations require leachate to be collected and treated to avoid ground or surface water contamination. Composite bottom liners are required, consisting of an HDPE geomembrane at least 60 mil over 2 ft of compacted soil with a hydraulic conductivity of less than 1 X 10 7 cm sec. However, equivalent liner systems can be used, subject to approval. The composite liner is covered with a drainage layer and leachate collection pipes to remove leachate for treatment and maintain a hydraulic head of less than 1 ft. Leachate is generally sent directly to a municipal wastewater treatment plant but can be pretreated, recirculated, or treated on-site.

Global Element Cycles

Most element cycles are not closed entities in ecosystems. This is particularly true for water, carbon and the nutrients nitrogen and sulphur. At the scale of landscapes resources are often imported and exported from one ecosystem to another. The figure shows the export of soluble organic carbon in humic and fulvic acids, which co-transport heavy metals, from boreal pine forests of Siberia. The dissolved organic carbon reaches the ocean via streams and rivers. The river is the Dubces, a tributary of the Yenisei. Photo E.-D. Schulze

Chemical Contamination

Heavy metals are also toxic to aquatic organisms and can impair feeding, respiration, physiological and neurological function, and reproduction, as well as promote tissue degeneration and increase rates of genetic mutation. Mercury is especially problematic because it is methylated in the anoxic soils of salt marshes and is then able to bioaccumulate in food chains. Salt marsh plants in urban areas take up, accumulate, and release heavy metals. Judith Weis and others have found lowered benthic diversity and impaired fish behavior in contaminated sites. Fish are slower to catch prey and less able to avoid predators where heavy metals contaminate their habitat.

Other Redox Reactions

Acid mine drainage of sulfidic deposits is accompanied by the leaching and mobilization of other heavy metals. These may include arsenic, cadmium, copper, lead, manganese, mercury, selenium, and zinc, which are all relatively toxic to most aquatic organisms. Consequently, surface waters downstream from acid mine drainage may be nearly devoid of all but microbial life until pH levels increase and iron and manganese precipitate out as oxy-hydroxides that scavenge those toxic elements. Heavy metals are not the only class of compounds which are readily adsorbed by iron and manganese oxy-hydroxides. Nutrients such as phosphate and nitrate also exhibit this same behavior under oxidizing conditions, and are thus released when the sediments become reducing and the Fe(iii) and Mn(iv) precipitates are solubilized to dissolved forms of Fe(ii) and Mn(ii). Thus, a change in the redox state ofsediments to more reducing conditions can result in the release of phosphate and nitrate to overlying...

Availability Limitations

Soil flushing and washing fluids must have good extraction coefficients low volatility and toxicity capability for safe and easy handling, and, most important, be recoverable and recyclable. This technology is very promising in extracting heavy metals from soil, although problems are likely in dry or organically-rich soils. Surfactants can be used to extract hydrophobic organisms. Soil type and uniformity are important. Certain surfactants, when tested for in-situ extraction, clogged soil pores and precluded further flushing.

Applicability Limitations

Chemical hydrolysis applies to a wide range of otherwise refractory organics. Hydrolysis is used to detoxify waste streams of carbamates, organophosphorous compounds and other pesticides. Acid hydrolysis as an in-situ treatment must be performed carefully due to potential mobilization of heavy metals. In addition, depending on the waste stream, products may be unpredictable and the mass of toxic discharge may be greater than the waste originally input for treatment.

Alkaline Metal Dechlorination Description

Successive treatment includes additional centrifugation and filtration. By-products include chloride salts, polymers, and heavy metals. Several chemical dechlorination processes are based on a method developed by the Goodyear Tire and Rubber Company in 1980. The original method uses sodium naphthalene and tetrahydrofuran to strip chlorine atoms from PCBs, polymerizing the biphenols into an inert condensible sludge. The reactor is blanketed with nitrogen because the reagents are sensitive to air and water, and an excess of reagent to chlorine is required. The Goodyear Company has not commercially developed this technology however, several companies have modified the method by substituting their own proprietary reagents for the naphthalene. The equipment is mobile and can be transported on semi-trailers.

How Humans and Environment Are Coupled Examples

Environmental and social changes have had and are expected to have significant effects on coupled humanenvironment systems in the Arctic. The Arctic Monitoring and Assessment Program have stated that although the Arctic is a relatively clean environment, it continues to suffer from significant pollution hazards, especially with regard to heavy metals and persistent organic pollutants. At the same time, native Arctic peoples have also experienced significant social changes over the past three decades, establishing new relationships between local and national governments, becoming more closely connected to external markets and ways of life, and asserting their identity, rights, and culture in legal and policy forums. Three kinds of stressors interest the Arctic region (1) climate change with consequences on snow cover, sea ice, and extreme weather events (2) environmental pollution and (3) societal trends in terms of consumption, governance and regulation, and markets. These represent...

Management Of Native And Introduced Microorganisms

There are many cases in which soil organisms have been managed to improve plant growth and serve as biological control agents to suppress plant disease, inhibit weeds, control insects, or detoxify environmental pollutants (Table 17.5). Beneficial microorganisms directly promote plant growth through the creation of symbiotic associations with plant roots, release of phytohormones, induction of systemic resistance, suppression of pathogens, production of antibiotics, and reduction of heavy metal toxicity (Bowden and Rovira, 1999). Many of these organisms are naturally present in soil, although under some circumstances it may be necessary to increase their populations either by modifying the soil environment or through inoculation to enhance their abundance and activity.

Investigations on the etiology of cancer in the hudson river tomcod population

Studies were initiated to determine the etiology of the elevated prevalence ofhepatic tumors and pre-neoplastic lesions in the HR population driven by the hypothesis that the epizootic resulted from exposure to chemical contaminants. Initially, no relationship was found between the prevalence or size of lesions and levels of total PCBs, pesticides, or selected heavy metals (Smith et al., 1979 Dey et al., 1993). Unfortunately, levels of these toxicants were not compared between tomcod from the HR and cleaner rivers.

Manipulating Soil Populations For Bioremediation Of Xenobiotics

Bioremediation manages microorganisms to reduce, eliminate, contain, or transform contaminants present in soils, sediments, water, or air. Various forms of bioremediation have been documented throughout recorded history. The composting of agricultural residues and sewage treatment are based on the use of microorganisms to catalyze chemical transformations. Composting dates back to 6000 BCE, with the modern use of bioremediation beginning over 100 years ago with the design and operation of the first biological sewage treatment plant in Sussex, England, in 1891. Over the past several decades, in situ degradation of biologically foreign chemical compounds (solvents, explosives, polycyclic aromatic hydrocarbons, heavy metals, radionuclides, etc.) has been used as a cost-effective alternative to incineration or burial in landfills (Alexander, 1994). An advantage of bioremediation over other methods is that it transforms contaminants instead of simply moving them from one source to another...

Chemical Components Nutrients

Metal accumulation in aquatic organisms can have both acute and chronic effects, and negatively affect all components to the ecosystem. For example, copper levels near 2mgl can greatly reduce algal productivity, and the bioaccumulation of mercury, cadmium, and zinc causes reproductive and juvenile developmental problems in macroinvertebrates, mussels, and fish. Metal toxicity can also change with different environmental conditions such as temperature and pH. Much is still unknown about the effect of metals on aquatic systems, including the effect of chronic low doses and the interactive effects of multiple metals.

Microbial interactions with radionuclides

The environmental fate of a radionuclide is governed by the interplay between the background matrix of the radioactive material, the often complex chemistry of the radionuclide in question and a broad range of chemical factors associated with the environment that has been impacted by the radioactive material in question (Lloyd & Renshaw 2005b). In addition, microbial activity will have a profound effect on the solubility of radionuclides via a complex range of often overlapping mechanisms including biosorption, bioaccumulation, biotransformation, biomineralisation and microbially enhanced chemisor-ption of heavy metals (Fig. 11.1). For a more extensive discussion of these microbe radionuclide interactions, the reader is directed to the following reviews (Lloyd & Lovley 2001 Keith-Roach & Livens 2002 Pedersen 2005 Renshaw et al. 2007). A brief synopsis, focusing on interactions with subsurface micro-organisms, is given below. Biosorption describes the metabolism-independent sorption of...

Indices Based on Indicator Species

Borja in 2000, this index accounts not only for the presence of species indicating a given type of pollution, but also of species indicating a nonpolluted situation. In addition, it has been shown useful to assess other anthropogenic impacts, such as habitat physical disturbance, heavy metals inputs, etc. To apply it, the soft bottom macrofauna is divided into five groups, according to their sensitivity as a function of an increasing stress gradient Algae have also been looked upon as most favorable for heavy metals, pesticides, and radionuclides detection, Fucus, Ascophyllum, and Enteromorpha being the most utilized taxa.

Bioweathering by Fungi

Mineral Microbe Interaction

Bioweathering can be defined as the erosion, decay, and decomposition of rocks and minerals mediated by living organisms. One of the most important processes of bio-weathering is weathering mediated by microorganisms, including fungi. Fungi are well suited as weathering agents since they can be highly resistant to extreme environmental conditions such as metal toxicity, UV

Biological Wastewater Treatment Systems

Stage Phoredox Process

And are distinguished in terms of vegetation, soil type, and wild life. Mires such as fens and bogs are mainly subsurface wetlands with little open water. Bogs are isolated hydrological units that receive water only through precipitation, whereas fens have through flowing water. As water goes through such wetland areas it undergoes great chemical transformation. Both nutrients and elements like heavy metals that attach chemically (sorb) on solid surfaces are effectively removed such that water reaches a status corresponding to 'natural' water quality. The active processes include mechanical filtering of particulate (organic) matter in the porous material, sorption of phosphorus and heavy metals to the solid matrix, and nitrogen decomposing reactions caused by nitrifying and denitrifying bacteria in the upper soil layer. Good performance is commonly reported for the removal of biological oxygen demand (BOD), total suspended solids (TSS), phosphorus, and nitrogen. The high amounts of...

Proteomics in Phytoremediation Research

The enzymatic processes involved in metals accumulation by plants may not be as broadly explored as for organic metabolism and detoxification, but those investigations that have been undertaken for cadmium, lead, mercury, nickel, zinc, and a few other elements do delve deeply into the genetics and proteomics of these processes. The investigations of the proteomics of metal accumulation are similar to those used to define the role of enzymes in organic transformations and mineralization. Hyperaccumulating plants are the basis of proteomic and genetic characterizations supporting some applications, while specific genes and enzymes have been investigated for other applications of metals 'phytoaccumulation'. For 'phytosorption', much less is known about plant and algae cell wall characteristics and the effects on electrostatic attraction and formation of complexes or the role of polysaccharides, uronic acids, and sulfated polysacchar-ides that can bind heavy metals. Thus the selection of...

Definitions and Terminology Related to Biomagnification

Normalized Concentration

Biomagnification and food web biomagnification were originally coined from observations of chlorinated pesticide bioaccumulation in aquatic food webs. However, the term biomagnification (see Persistent Organic Pollutants) has been applied to other contaminants including mercury, heavy metals, and certain compounds of biogenic origin. The first demonstration of biomagnification was described for dichlorodiphenyldichloroethane (DDD), closely related to the pesticide dichlorodiphenyltrichlor-oethane (DDT), in Clear Lake California. Rachel Carson subsequently used the term 'biological magnifiers' in her book, Silent Spring, to describe how earthworms concentrate DDT residues from soil in their bodies and transfer these residues to robins who consume them which in turn achieve even greater concentrations of the pesticides than worms. The term 'biological magnification' was later used by Woodwell to describe the 'systematic increase in DDT residues with trophic level' in his description of...

Lake Restoration Methods

Biological control methods are also used. Water hyacinths and other macrophytes are a pest in many tropic lakes and reservoirs. Many methods have been tested to abate this pollution problem. The best method tested up to now seems to be the use of beetles, that is, a biological control method. The method has given at least partial success in Lake Victoria. Biological control has also been used as removal process for heavy metals. Freshwater mussels can be applied for cadmium clearance. Lemna trisulca is able to accumulate as much as 3.8 mg Cd per g dry weight.

Contributions of Paleoecology to Ecology

Paleoecology, particularly for the last 100 years, is making major contributions to assessing the 'health' of ecosystems in terms of contamination by heavy metals (e.g., Cu, Cd, Zn, Pb, Ni, and As) and persistent organic pollutants (e.g., polycyclic aromatic hydrocarbons), of eutrophication by nutrients (e.g., N and P), and of recovery following decreases in the atmospheric deposition of 'acid rain'. Figure 5 A stratigraphical diagram from Holetjorn, a small hill-top lake in southwest Norway that covers the last 250-300 years. The diagram shows the decrease in lake-water pH beginning at about 1890. This acidification coincides with the beginning of the deposition of carbonaceous particles formed by the high temperature combustion of fossil fuels. The concentrations of the heavy metals Cu and Pb also increase at about 1914, reflecting atmospheric contamination due to industrialization and the use of lead in petrol. There is a small decline in Calluna vulgaris (heather, lyng) pollen...

Restoration of habitats impacted by human activities

Ecology Histogram

Land that has been damaged by mining is usually unstable, liable to erosion and devoid of vegetation. Tony Bradshaw, the father of restoration ecology, noted that the simple solution to land reclamation is the reestablishment of vegetation cover, because this will stabilize the surface, be visually attractive and self-sustaining, and provide the basis for natural or assisted succession to a more complex community (Bradshaw, 2002). Candidate plants for reclamation are those that are tolerant of the toxic heavy metals present such species are characteristic of naturally metalliferous soils (e.g. the Italian serpentine endemic Alyssum bertolonii) and have fundamental niches that incorporate the extreme conditions. Moreover, of particular value are ecotypes (genotypes within a species having different fundamental niches - see Section 1.2.1) that have evolved resistance in mined areas. Antonovics and Bradshaw (1970) were the first to note that the intensity of selection against intolerant...

Radioactive Contaminants in Human Food Chains

In studying these situations with fish and wildlife, radionuclide uptake and concentration in natural food chains frequently fails to conform to the expected pattern of contaminant-level biomagnification or trophic-level concentration in consumers feeding at higher trophic levels. Although top carnivores frequently show the highest levels of heavy metals or organic contaminants, in the case of radionuclide contamination highest levels are often showed by herbivores feeding lower on the food chain.

Solid Waste Treatment

Extending beyond water presence, a number of additional ambient environmental conditions come into play. Nutrient availability will certainly be an issue, not only in regard to the macroscale distribution of carbon and nitrogen (i.e., for which a C N ratio of 20 1 is typically considered optimal), but also in terms of the available presence of lower-level essential elements (e.g., phosphorus, sulfur, potassium, iron, calcium). While the pH of the constitutive moisture must also be suitably conducive to microbial activity, fermentative metabolism will progressively release weak organic acids that could well shift the pH to a more acidic, and less optimal, state. In fact, a downward shift in pH of this sort might accordingly escalate the undesired rate of trace metals leaching from the waste matrix, thereby leading to inhibitory metal toxicity.

Partial List Of Suppliers

ORP measurement is important in wastewater treatment applications. Examples of these applications are the removal of heavy metals, such as chromium, from metal finishing wastewater and cooling tower blowdown streams. ORP sensors are also used in cyanide removal, which is often required when heavy metals are removed. In sanitary wastewater treatment, ORP measurement controls the addition of an oxidant for odor control. Also, in most aerobic or anaerobic biological digestion processes, bacterial health can be judged on the basis of ORP measurements.

Ecological Footprint and Biocapacity Accounting

Many materials and pollutants place demands on the biosphere primarily by reducing the ability of ecosystems to provide goods and services, which leads to a loss in biocapacity. Toxics, heavy metals, and other persistent pollutants fall into this category. The amount of bioproductive area required to mine mercury, for example, is vanishingly small compared to the extent of the ecosystems that this metal affects. Similarly, the area required to absorb this product is an undefined quantity, as ecosystems do not have a well-defined or understood ability to assimilate this metal naturally. As a result, the impacts of mercury, as well as other toxics, do not appear primarily in the material's footprint but rather in the widespread loss of biocapacity that it can cause when released widely into the environment.

Stability And Product Quality

Often the criteria used are legal regulations such as those for heavy metals and pathogens. Recently, federal regulations have been issued for the use and disposal of sewage sludge, including compost (U.S. EPA 1993). States are now in the process of adopting these regulations or formulating more stringent regulations.

Hydrolysisadsorption Process

Recycling calcium in the sludge can reduce the sludge disposal problems associated with the large quantities of chemicals. Heavy metals are also precipitated into the lime sludge. Wastewater treatment facilities can expand their plant size by adding modular units such as carbon columns or reactor-clarifiers.

Emission Control Devices

Fabric filters cannot operate at the high temperatures at which gases exit the boiler without risk of fire. Thus, placing the scrubber between the boiler and the fabric filter or ESP permits cooling and often humidification that prevent fire. Cooling the gases also plays a role in reducing acid gas, mercury, and dioxin emissions. Dioxins and heavy metals are trapped more effectively by particulate control devices when they are first condensed out of the flue gas and adsorbed onto the surface of particulate matter, as happens in a scrubber-condenser system.

Pollution acid rain and forest decline

Acid Rain Pollution Facts

Acid rain and nitrogen enrichment are frequently accompanied by heavy metal pollution. This can come from the mobilization of heavy metals already in soils due to increasing acidity, possibly supplemented by pollution associated with the industrial processes causing acid rain. Bedrock can contain a suite of up to 38 heavy metals (defined as those with a density greater than 5 g cm-3) which are potentially toxic to life, usually by damaging proteins and enzymes. The commonest found in polluted soils are cadmium, arsenic, chromium, mercury (very toxic) lead, nickel (moderately toxic) boron, copper and zinc (least toxic). Some of these are, of course, essential micronutrients in low concentrations. Heavy metals can cause direct toxicity to roots and they can disrupt nutrient uptake causing deficiencies. A large number of trees are sensitive to metal contamination in Europe these include silver birch Betula pendula, ash Fraxinus excelsior, rowan Sorbus aucuparia, small-leaved lime Tilia...

Specific and Unspecific Reactions to Stress

Or take place only to a very small degree. An example of this is the formation of heat shock proteins (see Chap. 1.3.4.2). The modification of the basic metabolism could be interpreted as an unspecific reaction, whilst the production of heat shock proteins would be considered a specific stress reaction of the organism. The differentiation of these two components of a stress reaction is based on the findings of Hans Selye (1973), a Canadian general practitioner, who, in the 1970s, summarised the various complexes of stress reactions of human beings as follows Everything which endangers life causes stress reactions and adaptive reactions. Both types of reactions are partly specific and partly unspeci-fic. Contrary to plants there is, in humans, also a strong psychic-humoral stress component. The concept of both components of the stress reaction is complicated by the fact that even the specific reactions often lack specificity The above-mentioned heat shock proteins also assist the...

Contaminant Sources And Effects

The purpose of this section is to identify and describe the effects of significant environmental contaminants and other anthropogenic processes capable of disrupting ecosystems. We have focused on major pesticides (including organophosphorus and carbamate anticholinesterases and persistent organochlorines), petroleum and PAHs, heavy metals (lead and mercury), selenium, polyhaloge-nated aromatic hydrocarbons, and urban runoff. Toxicity of other metals and trace elements is included in Chapter 40 on amphibian declines, Chapter 44 on trace element interactions, and in three of the case history chapters. Chapters in this section on other important anthropogenic processes include nuclear and thermal contamination, global effects of deforestation, pathogens and disease, and abiotic factors that interact with contaminants. Lead (Pb) is a nonessential, highly toxic heavy metal, and all known effects of lead on biological systems are deleterious. According to Pattee and Pain (Chapter 15),...

Ecotoxicological Case Study II Contamination of Agricultural Products by Cadmium and Lead

The uptake of heavy metals from municipal sludge by plants has previously been modelled (see J0rgensen, 1975, 1976b). This model can briefly be described as follows. Depending on the soil composition it is possible to find a distribution coefficient for various heavy metal ions, i.e., the fraction of the heavy metal that is dissolved in the soil-water relative to the total amount. The distribution coefficient was found by examining the dissolved heavy metals relative to the total amount for several different types of soil. Correlation between pH, the concentration of humic substances, clay and sand in the soil on the one hand, and the distribution coefficient on the other, was also determined. The uptake of heavy metals was considered a first-order reaction of the dissolved heavy metal.