Egrets as Monitors of Trace-Metal Contamination in Wetlands of Pakistan
01 Oct 2003-Archives of Environmental Contamination and Toxicology (Springer-Verlag)-Vol. 45, Iss: 3, pp 399-406
TL;DR: Assessment of trace element contamination at three wetlands in Pakistan used as indicators the eggs and the feathers of colonial waterbirds, particularly Little Egrets, their prey, and the sediments collected within their foraging areas found feathers of predatory birds such as the egrets are the best indicators of environmental contamination.
Abstract: Environments in Pakistan are subject to increasing pollution, but previous studies were very scanty. During 1999 and 2000, we assessed trace element contamination at three wetlands, Karachi Harbour (with presumed industrial-urban pollution), Taunsa Barrage (agricultural pollution), and Haleji Lake (relatively unpolluted), using as indicators the eggs and the feathers of colonial waterbirds, particularly Little Egrets, their prey, and the sediments collected within their foraging areas. The concentrations of As, Cd, Cr, Pb, Hg, Mn, Se, and Zn were generally within the normal background level, and mostly below the threshold that may affect bird survival or reproduction. However, somewhat high concentrations were found in fish from Karachi, for Pb that was at levels that may harm fish reproduction, and for Hg that was at limit concentration for human consumption. Alarming concentrations were found for Cr and Se in sediments from Karachi, that were above the critical levels for contaminated soil, and Se in eggs, that may affect egret reproduction. The differences among the three wetlands were less marked than hypothesized. The egret species within the same area differed in the concentration of certain elements in their eggs, possibly because females may have foraged in different habitats before breeding, whereas no interspecies difference was found in chick feathers, presumably because their food had been collected in similar habitats around the colony. High bioaccumulation from sediments to organic samples occurred for Hg, while Cd, Se, and Zn exhibited low accumulation; for all these elements, feathers of predatory birds such as the egrets are the best indicators of environmental contamination. On the other hand, As and Cr did not bioaccumulate, and the sediments, or the organisms low in the food chain, like fish or crustaceans, are better indicators of their presence in the environment than predatory birds.
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TL;DR: The study suggested that the feathers of cattle egret could be used as a bio-monitor of the local heavy metals contamination and identify relatively similar associations of metals and their sources of input.
Abstract: Concentrations of metals such as Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Ni, Pb, and Zn were analyzed in the feathers of cattle egret (Bubulcus ibis) from three breeding colonies in the Punjab province, Pakistan. The mean concentrations of Ca, Cd, Fe, Pb and Mn were significantly different between the three study sites (River Chenab, River Ravi and Rawal Lake Reservoir). The mean concentrations of Ca, Cd, Fe and Mn were significantly greater at the River Chenab heronry and Cr, Co, Zn, and Pb concentrations at the River Ravi heronry. The feathers of cattle egrets collected from the Rawal Lake Reservoir heronry were least contaminated. Multivariate statistical methods viz., Factor Analysis based on Principal Component Analysis (FA/PCA); Hierarchical Cluster analyses (HACA), and Correlation Analyses identified relatively similar associations of metals and their sources of input. Metals such as Ca, Mg, and K were related with natural input from parent rock material whereas trace metals viz., Cu, Cd, Co, Pb, Ni, and Zn were associated mainly with anthropogenic processes. Metals such as Fe, Mn, and Li were either correlated with natural input or with anthropogenic activities. Concentration of heavy metals such as Cd, Pb, and Cr were well above the threshold level that can cause adverse effects in birds and pose menace to the cattle egrets population in Pakistan. The study suggested that the feathers of cattle egret could be used as a bio-monitor of the local heavy metals contamination.
134 citations
Cites background or result from "Egrets as Monitors of Trace-Metal C..."
...…river Chenab site, 138.4 lg/g from the Rawal Lake Reservoir and 155.2 lg/g from the River Ravi site) was lower than to those found in the study of Boncompagni et al. (2003) in feathers of little egret, and intermediate egrets, and greater to those for feathers of cattle egret from Taunsa wetland…...
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...However, these concentrations were greater to those reported for little egret (2.7 ppm), intermediate egret (2.2 ppm) from the Haliji Lake wetland, Pakistan ( Boncompagni et al. 2003 ), common eider (2.6 and 1.2 lg/g) and tufted puffin (0.7 and 0.5 lg/g) from the Aleutian Chain of Alaska (Burger and Gochfeld 2008) and lower to those reported for pigeon guillemots (0.9‐1.75 lg/g) collected from the Alaska (Burger et al. 2007)....
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...intermediate egret from Haliji, and cattle egret from Tunassa barrage wetland, Pakistan ( Boncompagni et al. 2003 ), red-footed booby and great frigate bird from Midway Atoll, Northern Pacific Ocean (Burger and Gochfeld 2000a), Laggar falcon from different districts of Pakistan (Movalli 2000) and Franklin gulls in the United States (Burger 1996)....
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...The mean Zn concentration in the current study (133.8 lg/g from the river Chenab site, 138.4 lg/g from the Rawal Lake Reservoir and 155.2 lg/g from the River Ravi site) was lower than to those found in the study of Boncompagni et al. (2003) in feathers of little egret, and intermediate egrets, and greater to those for feathers of cattle egret from Taunsa wetland of Pakistan (Table 4). Similarly, the mean Zn concentration was also lower to ......
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...Attempts have also been made to assess and monitor heavy metals contamination in various environmental compartments in Pakistan (Movalli 2000; Boncompagni et al. 2003; Qadir et al. 2008)....
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TL;DR: The bioaccumulation ratios in eggs and feathers of the cattle egret, their prey, and the sediments from their foraging habitats, confirmed that avian feathers are a convenient and non-destructive sampling tool for the metal contamination.
129 citations
Cites background or methods or result from "Egrets as Monitors of Trace-Metal C..."
...The Zn concentrations reported by our study are in agreement with those found in avian feathers by Boncompagni et al. (2003) and Nighat et al. (2013) for Pakistan, by Dauwe et al. (2002) for Belgium, and by Zhang et al. (2006) and Deng et al. (2007) for China....
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...…egrets fro concentrations found in our study were comparable to those in the feather of species of the family Ardeidae from Pakistan and China (Malik and Zeb, 2009; Burger, 1993) but were higher than those reported from agricultural areas of Pakistan (Boncompagni et al., 2003; Ullah et al., 2014)....
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...The Pb concentrations reported in other studies from Pakistan (Movalli, 2000; Boncompagni et al., 2003; Malik and Zeb, 2009; Ullah et al., 2014; Nighat et al., 2013) were far lower than those measured in our case....
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...…and Zeb (2009) and Ullah et al. (2014) documented moderate pollution levels for sub-urban and agricultural areas of Punjab, and Movalli (2000), and Boncompagni et al. (2003) reported for southern Pakistan, the concentrations of trace metals that were comparable to the minimum values found in our…...
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...Heavy metals are non-biodegradable environmental contaminants that may accumulate in the upper levels of the food chains, in relation to the habitat and dietary preferences of each species (Boncompagni et al., 2003)....
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01 Jan 2006
TL;DR: The activities that have been executed in Animal House Facilities of IPEN, including the refurbishment project and the adaptation of the facilities are described.
Abstract: The production and the supply of high quality laboratory animals have fundamental importance for the accomplishment of vanguard scientific research, with reproducibility and universality. The quality of those animals depends, largely, of the available facilities for their production and lodging, to assure the demanded sanitary control and animals’ welfare, in agreement with the ethical principles that control the activity. The facilities also have to fill out other requirements, such as: the functionality of the environments to make possible the suitable and efficient handling of the animals, facilitating the execution of the routine activities; the respect to ergonomic principles to provide a safe environment and the operators’ well being. The facilities design is of vital importance so that the mentioned requirements can be reached. The project of the Nuclear and Energy Research Institute (IPEN) Animal House Facilities was accomplished in the year of 1964. However, by that time there were not the current recommendations with respect to the sanitary, genetic and environmental controls. The facility was planned with the objective of being a production unit and a local for keeping of defined animals from sanitary, genetic and environmental point of view. Nevertheless, the original unit drawing presents an unsuitable distribution of the area where animals are stocked and also different activities are performed. The Animal House Facilities occupy an area of 840 m, with one pavement, where the production areas and the stock of original animal models of the own Institution are distributed, as well as the maintenance of animals from other national or foreigner institutions. It supplies rats and mice for biological tests of radiopharmaceutical lots, produced in IPEN, before they be sent to hospitals and clinics spread out in Brazil, for use in Nuclear Medicine. It also supplies rats and mice for tests of odontological materials, for tests with growth hormones and for researches of new pharmaceuticals and radiopharmaceuticals, among others applications. Many of the animals models produced in IPEN are unique in Brazil and they constitute, therefore, an important patrimony that should be preserved. This paper describes the activities that have been executed in Animal House Facilities of IPEN, including the refurbishment project and the adaptation of the facilities.
128 citations
TL;DR: In this paper, the muscle and viscera of large tilapia and snakeheads were found to have significant bioaccumulations of Cd (BAF: 165-1271 percent).
72 citations
Cites background from "Egrets as Monitors of Trace-Metal C..."
...Barrage and Haleji Lake in Pakistan (Boncompagni et al., 2003)....
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...…of non-essential elements (e.g., Cd, Hg, and Pb) in different organs and tissues of Ardeid, such as feathers (Abdennadher et al., 2011; Zhang et al., 2006), liver, kidney, muscle (Jayakumar and Muralidharan, 2011; Kim and Koo, 2011) and eggs (Boncompagni et al., 2003; Zhang et al., 2006)....
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..., 2006), liver, kidney, muscle (Jayakumar and Muralidharan, 2011; Kim and Koo, 2011) and eggs (Boncompagni et al., 2003; Zhang et al., 2006)....
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TL;DR: Eggshells of grey herons appeared to be good bioindicators for monitoring of Cu and Pb in Nallihan Bird Paradise.
Abstract: Concentrations of four trace elements (Cd, Ni, Cu and Pb) were determined in eggshells of grey heron (Ardea cinerea) and black-crowned night herons (Nycticorax nycticorax) from Nallihan Bird Paradise, which is located in the northern part of Sariyar Dam Reservoir, Turkey. Results indicated that, within the same area, these ardeid species differed in the levels of Cd, Cu and Pb in their eggshells (generally grey heron > night heron), possibly because females may have foraged in different habitats and regions. Geometric means found for Cd, Ni, Cu and Pb in eggshells were 0.931 mg/kg, 0.405 mg/kg, 6.755 mg/kg and 4.567 mg/kg, respectively, for grey heron; and 0.230 mg/kg, 0.220 mg/kg, 1.369 mg/kg and 1.108 mg/kg, respectively, for night heron. High bioaccumulation from sediments to eggshells occured for Cu and Pb, while Cd and Ni exhibited low accumulation. Bioaccumulation ratios were calculated as 19.63 (Cu) and 22.9 (Pb) in eggshells of grey herons. In conclusion, eggshells of grey herons appeared to be good bioindicators for monitoring of Cu and Pb in Nallihan Bird Paradise.
58 citations
References
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TL;DR: In this paper, a simple and widely accepted multiple test procedure of the sequentially rejective type is presented, i.e. hypotheses are rejected one at a time until no further rejections can be done.
Abstract: This paper presents a simple and widely ap- plicable multiple test procedure of the sequentially rejective type, i.e. hypotheses are rejected one at a tine until no further rejections can be done. It is shown that the test has a prescribed level of significance protection against error of the first kind for any combination of true hypotheses. The power properties of the test and a number of possible applications are also discussed.
20,459 citations
"Egrets as Monitors of Trace-Metal C..." refers methods in this paper
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01 Jan 1987
TL;DR: A review of the available literature on the ecological and toxicological aspects of mercury (Hg) in the environment, with special reference to fish and wildlife resources, is reviewed and summarized in this paper.
Abstract: SUMMARY Available literature on the ecological and toxicological aspects of mercury (Hg) in the environment, with special reference to fish and wildlife resources, is reviewed and summarized. Subdivisions include sources, chemical properties, background concentrations, acute and chronic toxicity, sublethal effects, and proposed criteria to protect sensitive resources. Mercury has been used by man for at least 2,300 years, most recently as a fungicide in agriculture, in the manufacture of chlorine and sodium hydroxide, as a slime control agent in the pulp and paper industry, in the production of plastics and electrical apparatus, and in mining and smelting operations. Mercury burdens in some environmental compartments are estimated to have increased up to 5X precultural levels, primarily as a result of man's activities. The construction of artificial reservoirs, for example, which releases Hg from flooded soils, has contributed to the observed elevation of Hg concentrations in fish tissues from these localities. Elevated levels of Hg in living organisms in Hg-contaminated areas may persist for as long as 100 years after the source of pollution has been discontinued. One major consequence of increased mercury use, coupled with careless waste disposal practices, has been a sharp increase in the number of epidemics of fatal mercury poisonings in humans, wildlife, and aquatic organisms. Most authorities agree on six points: (1) mercury and its compounds have no known biological function, and the presence of the metal in the cells of living organisms is undesirable and potentially hazardous; (2) forms of mercury with relatively low toxicity can be transformed into forms of very high toxicity, such as methylmercury, through biological and other processes; (3) mercury can be bioconcentrated in organisms and biomagnified through food chains; (4) mercury is a mutagen, teratogen, and carcinogen, and causes embryocidal, cytochemical, and histopathological effects; (5) some species of fish and wildlife contain high concentrations of Hg that are not attributable to human activities; (6) anthropogenic use of Hg should be curtailed, as the difference between tolerable natural background levels of Hg and harmful effects in the environment is exceptionally small. Concentrations of total Hg lethal to sensitive, representative, nonhuman species range from 0.1 to 2.0 ug/l (ppb) of medium for aquatic organisms; from 2,200 to 31,000 ug/kg body weight (acute oral) and 4,000 to 40,000 ug/kg (dietary) for birds; and from 100 to 500 ug/kg body weight (daily dose) and 1,000 to 5,000 ug/kg diet for mammals. Organomercury compounds, especially methylmercury, …
1,135 citations
23 Feb 2011
TL;DR: Residue Analyses: How They were used to Assess the Hazards of Contaminants to Wildlife, J.J. Niimi Toxicological Implications of PCB Residues in Mammals, M.A. Cooke and M.S. Johnson Cadmium in Birds, R.C. Johnson Toxicological Significance of Mercury in Freshwater Fish, and more.
Abstract: Residue Analyses: How They Were Used to Assess the Hazards of Contaminants to Wildlife, J.O. Keith DDT, DDD, and DDE in Birds, L.J. Blus Dieldrin and Other Cyclodiene Pesticides in Wildlife, D.B. Peakall Other Organochlorine Pesticides in Birds, S.N. Wiemeyer PCBs in Aquatic Organisms, A.J. Niimi Toxicological Implications of PCB Residues in Mammals, M.A. Kamrin and R.K. Ringer PCBs and Dioxins in Birds, D.J. Hoffman, C.P. Rice, and T.J. Kubiak Dioxins: An Environmental Risk for Fish? D. Sijm and A. Opperhuizen Polycyclic Aromatic Hydrocarbons in Marine Mammals, Finfish, and Molluscs, J. Hellou Lead in Waterfowl, D.J. Pain Interpretation of Tissue Lead Residues in Birds Other Than Waterfowl, J.C. Franson Lead in Mammals, W.-C. Ma Toxicological Significance of Mercury in Freshwater Fish, J.G. Wiener and D.J. Spry Mercury in Birds and Terrestrial Mammals, D.R. Thompson Metals in Marine Mammals, R.J. Law Cadmium in Small Mammals, J.A. Cooke and M.S. Johnson Cadmium in Birds, R.W. Furness Heavy Metals in Aquatic Invertebrates, P.S. Rainbow Selenium in Aquatic Organisms, A.D. Lemly Selenium in Birds, G.H. Heinz Fluoride in Birds, W.J. Fleming Fluoride in Small Mammals, J.A. Cooke, I.C. Boulton, and M.S. Johnson
893 citations
"Egrets as Monitors of Trace-Metal C..." refers background in this paper
...2000), and they were below the concentration associated with toxic effects in freshwater fish (5–10 ppm wet wt; Beyer et al. 1996)....
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...The threshold that seems to affect fish is 4 ppm dry wt (Beyer et al. 1996), and the values we found in fish from Pakistan were below this concentration....
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...The concentrations we found in eggs from Pakistan were similar to these relatively high levels, and were in some cases higher than the threshold, 3–5 ppm dry wt, that should affect avian reproduction (Beyer et al. 1996; Ohlendorf et al. 1986)....
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Book•
01 Jan 1993
TL;DR: In this article, a basic model of environmental pollution is presented, which includes the transport and behaviour of pollutants in the environment, as well as the effects of pollutants on humans and other organisms.
Abstract: One Basic Principles.- 1 Introduction.- 1.1 Pollution in the modern world.- 1.2 Definition of pollution.- References.- Further reading.- 2 Transport and behaviour of pollutants in the environment.- 2.1 A basic model of environmental pollution.- 2.2 Sources of pollutants.- 2.3 The pollutants.- 2.3.1 Classification of hazardous substances in the USA.- 2.3.2 European Community Dangerous Substances Directive.- 2.3.3 UK priority list of pollutants.- 2.3.4 Pesticides.- 2.3.5 Indoor pollution.- 2.4 Physical processes of pollutant transport and dispersion.- 2.4.1 Transport media.- 2.4.2 Transport of pollutants in air.- 2.4.3 Some important types of reactions which pollutantsundergo in the atmosphere.- 2.5 Transport of pollutants in water.- 2.5.1 Biochemical processes in water (involving microorganisms).- 2.6 The behaviour of pollutants in the soil.- 2.6.1 The composition and physico-chemical properties of soils.- 2.6.2 Cation and anion adsorption in soils.- 2.6.3 Adsorption and decomposition of organic pollutants.- 2.7 Concluding remarks.- References.- 3 Toxicity and risk assessment of environmental pollutants.- 3.1 Basic principles of toxicology.- 3.2 Effects of pollutants on animals and plants.- 3.2.1 Effects of pollutants on humans and other mammals.- 3.2.2 Teratogenesis, mutagenesis, carcinogenesis and immunesystem defects.- 3.2.3 Ecotoxicology.- 3.3 Assessment of toxicity risks.- 3.3.1 Pollutants in contaminated land.- 3.3.2 Pollutants in drinking water.- 3.3.3 Toxic or explosive gases and vapours.- References.- 4 Analysis and monitoring of pollutants - organiccompounds.- 4.1 Chromatography.- 4.2 Thin layer chromatography (TLC).- 4.2.1 Separation of pesticides.- 4.2.2 Separation of metal cations.- 4.3 Gas liquid chromatography (GLC).- 4.3.1 Detection of eluted substances.- 4.3.2 Principal parameters.- 4.3.3 Optimum operating conditions.- 4.3.4 Capillary columns for GLC.- 4.3.5 Analysis of urban air pollution.- 4.3.6 Detection by mass spectrometry.- 4.4 High pressure liquid chromatography (HPLC).- 4.4.1 The components.- 4.4.2 Detectors.- 4.4.3 Analysis of polluted air.- 4.4.4 Analysis of polluted water.- 4.4.5 Trace enrichment followed by GLC analysis.- 4.5 Pollution by metals - atomic absorption spectroscopy.- 4.5.1 Historical.- 4.5.2 Basic theory of atomic absorption and emission.- 4.5.3 The Lambert-Beer law.- 4.5.4 Instrumental details.- 4.5.5 Interferences.- 4.5.6 The determination of sodium in concrete by AAS.- 4.5.7 Sample preparation.- 4.5.8 Precision and accuracy of measurement.- 4.5.9 Graphite furnace AAS.- 4.6 A plasma source.- 4.6.1 ICP-mass spectrometry.- 4.7 Analytical quality assurance.- 4.8 Environmental monitoring.- 4.8.1 Introduction.- 4.8.2 Monitoring emissions.- References.- Further reading.- Two the Pollutants.- 5 Inorganic pollutants.- 5.1 Ozone.- 5.1.1 Historical.- 5.1.2 Formation.- 5.1.3 Physical properties and structure.- 5.1.4 The ozone layer.- 5.1.5 Factors which disturb the natural environment.- 5.1.6 Chemistry of stratospheric CFC.- 5.1.7 Control measures.- 5.1.8 Ozone in the troposphere.- 5.1.9 Diurnal variations of ozone levels.- 5.1.10 Toxicity and control.- 5.2 Oxides of carbon, nitrogen and sulphur.- 5.2.1 Carbon dioxide.- 5.2.2 Oxides of nitrogen.- 5.2.3 Oxides of sulphur.- 5.3 Heavy metals.- 5.3.1 General properties.- 5.3.2 Biochemical properties of heavy metals.- 5.3.3 Sources of heavy metals.- 5.3.4 Environmental media affected.- 5.3.5 Heavy metal behaviour in the environment.- 5.3.6 Toxic effects of heavy metals.- 5.3.7 Analytical methods.- 5.3.8 Examples of specific heavy metals.- 5.4 Other metals and inorganic pollutants.- 5.4.1 Aluminium.- 5.4.2 Beryllium.- 5.4.3 Fluorine.- 5.5 Radionuclides.- 5.5.1 History and nomenclature.- 5.5.2 Types of radioactive emission.- 5.5.3 Units of energy and measurement of toxicity.- 5.5.4 Radioactive potassium.- 5.5.5 Production of radionuclides by artificial means.- 5.5.6 Nuclear fission.- 5.5.7 Power generation I n nuclear reactors.- 5.5.8 Nuclear reactor types.- 5.5.9 The future of nuclear power.- 5.5.10 Observations on major accidents.- 5.5.11 Radioactive release within buildings.- 5.5.12 Social aspects of nuclear power generation.- 5.5.13 Power from thermal fusion.- 5.5.14 Cold fusion.- 5.6 Mineral fibres and particles.- 5.6.1 General aspects.- 5.6.2 Analysis.- 5.6.3 Examples of mineral pollutants.- References.- Further reading.- 6 Organic pollutants.- 6.1 Smoke.- 6.2 Methane and other hydrocarbons - coal and oil as sources.- 6.2.1 The formation of coal.- 6.2.2 Petroleum.- 6.2.3 Methane.- 6.2.4 Higher alkanes.- 6.2.5 Polycyclic aromatic hydrocarbons (PAH).- 6.3 Organic solvents.- 6.3.1 Adhesives.- 6.3.2 Coatings and inks.- 6.3.3 Aerosol sprays.- 6.3.4 Metal cleaning.- 6.3.5 Dry cleaning of clothes.- 6.3.6 Solvent toxicology.- 6.3.7 Organochlorine compounds.- 6.3.8 Detergents.- 6.3.9 Indoor pollution.- 6.4 Organohalides: pesticides, PCBs and dioxins.- 6.4.1 Historical.- 6.4.2 Organochlorine production.- 6.4.3 DDT (dichlorodiphenyl trichloroethane).- 6.4.4 Lindane, hexachlorocyclohexane.- 6.4.5 Some other chlorinated pesticides.- 6.4.6 Organochlorine herbicides.- 6.4.7 Toxic effects of insecticides.- 6.4.8 Control of pesticides.- 6.4.9 Vinyl chloride and polyvinyl chloride.- 6.4.10 Polychlorobiphenyls.- 6.4.11 Toxic substances in herbicides.- 6.4.12 Metabolism of chloraromatic compounds.- 6.4.13 Disposal of organochlorine compounds.- 6.4.14 Cremation or burial.- 6.4.15 Use of decay organisms.- 6.5 Natural, organophosphorus and carbamate pesticides.- 6.5.1 Naturally occurring pesticides.- 6.5.2 Organophosphorus pesticides.- 6.5.3 Carbamate pesticides.- 6.6 Odours.- 6.6.1 Important properties of odours.- 6.6.2 Methods of odour control.- 6.6.3 Methods of odour treatment.- References.- Further reading.- Three Wastes and other Multi-Pollutant Situations.- 7 Wastes and their disposal.- 7.1 Introduction.- 7.2 Amounts of waste produced.- 7.2.1 Industrial wastes.- 7.2.2 Municipal wastes.- 7.3 Methods of disposal of municipal wastes.- 7.3.1 Landfilling.- 7.3.2 Incineration.- 7.3.3 Composting.- 7.3.4 Recycling.- 7.4 Sewage treatment.- 7.5 Hazardous wastes.- 7.5.1 The nature and amount of hazardous waste produced.- 7.5.2 Hazardous waste management.- 7.5.3 New technologies for waste disposal.- 7.6 Long-term pollution problems of abandoned landfills containinghazardous wastes.- 7.6.1 Love Canal, New York, USA.- 7.6.2 Lekkerkirk, near Rotterdam, The Netherlands.- 7.7 Tanker accidents and oil spillages at sea.- 7.8 Other multi-pollutant situations.- 7.9 Chemical time bombs.- References.- Appendix Table of units and conversions.
889 citations
TL;DR: A critique of the current state of knowledge about effects of Hg on wildlife is presented as an aid to identifying missing information and to planning research needed for conducting a complete assessment of HG risks to wildlife.
Abstract: Wildlife may be exposed to mercury (Hg) and methylmercury (MeHg) from a variety of environmental sources, including mine tailings, industrial effluent, agricultural drainwater, impoundments, and atmospheric deposition from electric power generation. Terrestrial and aquatic wildlife may be at risk from exposure to waterborne Hg and MeHg. The transformation of inorganic Hg by anaerobic sediment microorganisms in the water column produces MeHg, which bioaccumulates at successive trophic levels in the food chain. If high trophic level feeders, such as piscivorous birds and mammals, ingest sufficient MeHg in prey and drinking water, Hg toxicoses, including damage to nervous, excretory and reproductive systems, result. Currently accepted no observed adverse effect levels (NOAELs) for waterborne Hg in wildlife have been developed from the piscivorous model in which most dietary Hg is in the methyl form. Such model are not applicable to omnivores, insectivores, and other potentially affected groups, and have not incorpotated data from other important matrices, such as eggs and muscle. The purpose of this paper is to present a comprehensive review of the Hg literature as it relates to effects on wildlife, including previously understudied groups. We present a critique of the current state of knowledge about effects of Hg on wildlife as an aid to identifying missing information and to planning research needed for conducting a complete assessment of Hg risks to wildlife. This review summarizes the toxicity of Hg to birds and mammals, the mechanisms of Hg toxicity, the measurement of Hg in biota, and interpretation of residue data.
836 citations
"Egrets as Monitors of Trace-Metal C..." refers background in this paper
...Uptake and accumulation of Hg by birds depends on multiple factors, diet, age, and metabolism (Lewis et al. 1993; Wolfe et al. 1998)....
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