ECOTOXICOLOGICAL CHEMISTRY

INTERACTIONS BETWEEN ENVIRONMENTAL CHEMISTRY, TOXICOLOGY AND ECOTOXICOLOGICAL CHEMISTRY... 

Discuss the ecotoxicological chemistry of parathion and malathion insecticides. 

C. Tomlin, ed.. The Pesticides Manual A World Compendium, Incorporating the Agrochemicals Handbook, 10th ed.. The British Crop Protection Council and The Royal Society of Chemistry, Crop Protection PubHcations, Cambridge, U.K., 1994. Includes 725 entries by common name in alphabetic order, with chemical stmcture, chemical name(s), molecular formula, CAS Registry Number, physicochemical properties, commercialisation, mode of action, uses, trade names, analytical methods, mammalian toxicology, ecotoxicology, and environmental fate. 

The following brief account identifies only major groups of herbicides not mentioned elsewhere in the text, and is far from comprehensive. Their mode of action is only dealt with in a superficial way. From an ecotoxicological point of view, there has not been as much concern about their sublethal effects upon plants as there has been in the case of mammals, and there has not been a strong interest in the development of biomarker assays to establish their effects. The major concern has been whether weeds, or nontarget plants, have been removed following herbicide application—a rather easy matter to establish as plants are fairly sedentary. For a more detailed account of herbicide chemistry and biochemistry, see Hassall (1990). 

De Voogt, R (1996). Ecotoxicology of chlorinated aromatic hydrocarbons. In Chlorinated Organic Micropollutants, No 6 in series Issues in Environmental Science and Technology. R.E. Hester and R.M. Harrison (Eds.) Royal Society of Chemistry 89-112. 

Forbes, V.E. and Calow, P. (1999). Is the per capita rate of increase a good measure of population-level effects in ecotoxicology Environmental Toxicology and Chemistry 18, 1544-1556. 

Kedwards, T.J., Maund, S.J., and Chapman, PE. (1999a and 1999b). Community level analysis of ecotoxicological field studies 1 Biological Monitoring and 11 Replicated design studies. Environmental Toxicology and Chemistry 18, 149-157 and 158-166. 

Sometimes for some very potent pollutants analytical methodologies provide limits of detection (LODs) higher than the concentrations that cause effects, as derived from ecotoxicological studies. Therefore efforts in the field of analytical chemistry (see Sect. 2) are focused on making available the necessary analytical capabilities to detect pollutants at the required low levels found in the environment. This was the case of pharmaceuticals, illicit drugs, perfluorinated compounds (PFCs), sunscreens/UV filters, etc. few years ago. However, this list is likely to increase with new family candidates. 

Masaryk University, Faculty of Sci., EU Res. Ctre of Excellence for Environmental Chemistry and Ecotoxicology, Kamenice 126/3, CZ-625 00 Brno, Czech Republic... 

DelValls, T.A., Andres, A., Belzunce, M.J., Buceta, J.L., Casado-Martinez, M.C., Castro, R., Riba, I., Vigura, J.R., Blasco, J. (2004). Chemical and ecotoxicological guidelines for managing disposal of dredged material. Trends in Analytical Chemistry, vol 23, no 10-11. 

Rye, H., Nordtug, T., Tobiesen, A. and Osteorot, A. (1997) Drilling and well chemicals and their environmental impacts. A survey of amounts, ecotoxicological properties, dispersion and impacts in the marine environment. In Chemistry in the Oil Industry, 6th International Symposium, Ambleside, the Lake District, UK, 14—17 April 1997. Royal Society of Chemistry, Cambridge, p. 21. 

Since one of the main aims of green chemistry is to reduce the use and/or production of toxic chemicals, it is important for practitioners to be able to make informed decisions about the inherent toxicity of a compound. Where sufficient ecotoxicological data have been generated and risk assessments performed, this can allow for the selection of less toxic options, such as in the case of some surfactants and solvents [94, 95]. When toxicological data are limited, for example, in the development of new pharmaceuticals (see Section 15.4.3) or other consumer products, there are several ways in which information available from other chemicals may be helpful to estimate effect measures for a compound where data are lacking. Of these, the most likely to be used are the structure-activity relationships (SARs, or QSARs when they are quantitative). These relationships are also used to predict chemical properties and behavior (see Chapter 16). There often are similarities in toxicity between chemicals that have related structures and/or functional subunits. Such relationships can be seen in the progressive change in toxicity and are described in QSARs. When several chemicals with similar structures have been tested, the measured effects can be mathematically related to chemical structure [96-98] and QSAR models used to predict the toxicity of substances with similar structure. Any new chemicals that have similar structures can then be assumed to elicit similar responses. 

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