| Autor: |
Lee, G. Fred1, Jones, R. Anne1,2, Saleh, Farida Y.1,3 |
| Zdroj: |
Journal of Environmental Science & Health. Part B. Pesticides, Food Contaminants & Agricultural Wastes. Jan1982, Vol. 17 Issue 4, p409-437. 29p. |
| Abstrakt: |
In the U.S., water quality criteria and standards for pesticides in aquatic systems are generally equivalent to chronic exposure safe concentrations based on toxicity tests conducted in the laboratory where aquatic organisms are exposed to pesticides that are usually in soluble, generally more available forms. The water quality management agencies in the U.S. usually develop pesticide regulations based on the total pesticide concentration in water samples, using the worst case criteria for guidance or as the standard values. In natural water systems however, many pesticides tend to become strongly sorbed on particulate matter so that only a small part of the total pesticide concentration is available to aquatic life. Systems with large amounts of suspended sediments can thus often sustain larger total concentrations of certain pesticides without being harmful to aquatic life. Rather than assuming that all of the pesticide in a sample of lake, river, or ocean water is available to adversely affect aquatic life and using worst case criteria as enforceable limits, one should use the worst case water quality criteria as indicators of potential water quality problems. When the concentrations exceed the worst case criteria, a hazard assessment approach should be used to determine whether the apparent excessive concentrations represent actual environmental degradation. This approach more properly accounts for the availability of pesticides to aquatic life and the duration of organism exposure to the available forms. A recommended approach for establishing pesticide water quality standards and use regulations in Egypt is presented. The large‐scale pesticides use in some parts of Egypt may lead to the presence of high concentrations of pesticide residues in soils. These soils could be potentially significant sources of pesticides for surface and ground‐waters. At this time it appears that there is limited information on pesticide residue concentrations in the surface or groundwaters, or in aquatic organisms. An approach is presented to define the significance of Egyptian soil pesticide residues. It involves collecting and crit‐. ically evaluating existing residue data; developing a monitoring program to fill data gaps; development of Egyptian water quality criteria and standards, and organism tolerance levels; and comparing the critical concentration of pesticides developed for Egypt to existing concentrations. If excessive concentrations are found, then site‐specific studies should be conducted to evaluate the role of soil pesticide residues in causing the excessive concentrations. [ABSTRACT FROM PUBLISHER] |
| Databáze: |
GreenFILE |
| Externí odkaz: |
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