Lead contamination, environmental

Keywords Lead Environmental contamination, Air, Water, Sediments, Food, Human biological materials, Central Europe... 

In recent years, environmental contamination by lead, cadmium, and mercury has been repeatedly observed and has given rise to partly exaggerated reports. 

Capodaglio, G., Scarponi, G., P. Cescon. Lead contamination of seawaters with different anthropic influence. Ill International Conference "Environmental Contamination", Venice, Sept. 1988, pp. 505-407. 

The ancient Egyptians used lead as early as the fourth millennium b.c.e. Later, the Romans developed and expanded the use of lead during the Roman Empire to impressive levels, so lead is often referred to as the Roman metal. The large-scale use of the metal most probably caused considerable environmental contamination of food, drink, and the atmosphere (Nriagu 1983). 

Franson, J.C. 1996. Interpretation of tissue lead residues in birds other than waterfowl. Pages 265-280 in W.N. Beyer, G.H. Heinz, and A.W. Redmon-Norwood (eds.). Environmental Contaminants in Wildlife Interpreting Tissue Concentrations. CRC Press, Boca Raton, FL. 

Garcia, M.A., J. Alonso, M.I. Fernandez, and MJ. Melgar. 1998. Lead content in edible wild mushrooms in northwest Spain as indicator of environmental contamination. Arch. Environ. Contam. Toxicol. 34 330-335. Gatz, D.F., V.C. Bowersox, and J. Su. 1989. Lead and cadmium loadings to the Great Lakes from precipitation. Jour. Great Lakes Res. 15 246-264. 

Rolfe, G.L. and K.A. Reinbold. 1977. Environmental Contamination by Lead and Other Heavy Metals. Volume I Introduction and Summary. Univ. Illinois, Inst. Environ. Studies, Urbana-Champaign. 120 pp. 

Alary, J., P. Bourbon, J. Esclassan, J.C. Lepert, J. Vandaele, and F. Klein. 1983. Zinc, lead, molybdenum contamination in the vicinity of an electric steelworks and environmental response to pollution abatement by bag filter. Water Air Soil Pollut. 20 137-145. 

Even relatively small amounts of exothermic reaction or decomposition may lead to the loss of quality and product, to the emission of gas, vessel pressurization, and/or environmental contamination. In the worst case, an uncontrolled decomposition may accelerate into an explosion. 

Environmental contamination usually consists of a mixture of pollutants and their partially degraded derivatives. Such an ill-defined chemical mixture will eventually lead to the formation of an ecosystem of microbes. The individual member species cannot survive in the toxic and hostile environment. Effective bioremediation technologies should therefore invoke a mixture of microorganisms forming synergistic consortia. Any realistic bioremediation concept is based on the recognition that it is the concerted action of various species, which may bring about the desired clean-up effect. 

Determination of the roles of microelements and the human daily requirements can be very difficult due to their low concentrations in the human body and problems connected with the elimination of their constant inflow. Throughout the evolution process, the human body developed mechanisms to regulate the absorption of microelements and balance their levels within required ranges. Therefore, human bodies are adjusted to the natural levels at which those elements are present in the non-polluted environment and in non-contaminated foodstuffs. However, human industrial and economic activities are frequently and widely disturbing the environmental balance and leading to contamination of the environment, including foods, with trace elements. 

Food contamination may result from transmission of lead from glaze, enamel, or tinning on kitchen dishes, or from the lead on surfaces of containers or pipes used for storage, processing and transportation of food products. The occurrence of lead in food can also result from environmental contamination, as plants and animals may assimilate lead during growth and incorporate it into their tissues. The level of lead found in plant tissues is proportional to its concentration in the environment, and in cases of animals, the feed and water supplies also play important roles (Vreman et al., 1988 McLaughlin et ah, 1999 Sedki et ah, 2003). 

Arsenic is an ancient and well-known hazard and, along with lead and mercury, is an important environmental contaminant. The inorganic form is far more toxic than organic arsenic, which is commonly found in seafood. Arsenic-contaminated drinking water is a worldwide problem that affects millions of people. Human exposure also occurs from arsenic-treated lumber. 

Another development is due to the interest in polychlorodibenzofurans, spurred by their occurrence as environmental contaminants. Polychloro-phenols are manufactured in large amounts (150,000 tons per annum) and find a wide range of uses. The usual method of manufacture involves the hydrolysis of chlorobenzenes, and side reactions, favored by high temperature, can lead to the production of polychlorodibenzofurans and poly-chlorodibenzo-p-dioxins. The Seveso incident is well known." Polychloro-biphenyls are also widely used industrial chemicals, particularly in heat exchange systems, and their pyrolysis leads to the formation of polychloro-dibenzofurans. Polychlorodibenzofurans have also been detected in the fly ash and flue gases of incinerators and industrial heating plants. The most toxic of the polychlorodibenzofurans are 2,3,7,8-tetra-, 1,2,3,7,8-penta-, and 2,3,4,7,8-pentachlorodibenzofuran, and an extensive literature exists on the environmental pollution and the results of human exposure to these substances. A particularly tragic example of the latter occurred in 1968 in the Fukuoka prefecture of Japan after consumption of rice oil contaminated with a commercial polychlorobiphenyl. 

Laperche, V., Logan, T. J., Gaddam, P. Traina, S. J. 1997. Effect of apatite amendments on plant uptake of lead from contaminated soil. Environmental Science Technology, 31, 2745-2753. 

Rabinowitz, M. B. 1993. Modifying soil lead bioavailability by phosphate addition. Bulletin of Environmental Contamination and Toxicology, 51, 438-444. 

Stanforth, R. Qiu, J. 2001. Effect of phosphate treatment on the solubility of lead in contaminated soil. Environmental Geology, 41, 1-10. 

Yang, J., Mosby, D. E., Casteel, S. W. Blanchar, R. W. 2002. In vitro lead bioaccessibility and phosphate leaching as affected by surface application of phosphoric acid in lead-contaminated soil. Archives of Environmental Contamination and Toxicology, 43, 399-405. 

Halogenated alkanes are very useful as solvents in a variety of industrial processes (at one time they were the solvents of choice for the dry cleaning of clothes, for example). The scale of their use is such that their accidental or deliberate discharge into the environment can lead to long-term contamination problems. As is true for many environmental contaminants, the molecule originally released may not be a particular danger from an environmental perspeedve, but some product into which it is transformed may be considerably more cause for concern. 

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