Pesticides estimating

Thus the ADI in mg per kg per day is an estimate of the daily pesticide dietary intake that appears to be without risk over the entire human lifetime. ADI values are estabHshed and periodically reviewed by joint committees of the Eood and Agricultural Organization (EAO) and WHO of the United Nations. 

Pubhc concerns about pesticides in the diet of infants and children resulted in an expert committee convened by the U.S. National Academy of Sciences which devoted four years to the review of all available data. A consensus report was issued in 1993 (80). A number of recommendations for further work to more precisely define what constitutes the diet of infants and children were made. No risk could be estimated. The residue data reviewed by the panel were mainly from monitoring studies conducted by the PDA using multiresidue methods to analyze fresh produce and market basket samples collected from various geographic areas (81,82). These and other rehable scientific studies have demonstrated that relatively few food samples contain detectable residues. Most residues are far below estabhshed tolerances which are set above the maximum residue found in treated raw agricultural... 

A. L. Aspelin, Pesticide Industry Sales and Usage 1992 and 1993 Market Estimates, 733-K-94-001, U.S. Environmental Protection Agency, Washington, D.C., une 1994. 

Total sales of pesticides in 1995 were estimated at 10.4 biUion. The distribution of sales among various classes of pesticides is shown in Table 1. 

An extensive pesticide properties database was compiled, which includes six physical properties, ie, solubiUty, half-life, soil sorption, vapor pressure, acid pR and base pR for about 240 compounds (4). Because not all of the properties have been measured for all pesticides, some values had to be estimated. By early 1995, the Agricultural Research Service (ARS) had developed a computerized pesticide property database containing 17 physical properties for 330 pesticide compounds. The primary user of these data has been the USDA s Natural Resources Conservation Service (formerly the Soil Conservation Service) for leaching models to advise farmers on any combination of soil and pesticide properties that could potentially lead to substantial groundwater contamination. 

Indirect methods of estimating sorption have been used when actual measurement of sorption isotherm is impossible (44). For instance, sorption coefficients have been estimated from soil organic carbon and a specific surface of soil, and from semiempidcal equations using pesticide properties. 

The documented occurrence of pesticides in surface water is indicative that mnoff is an important pathway for transport of pesticide away from the site of appHcation. An estimated 160 t of atra2ine, 71 t of sima2ine, 56 t of metolachlor, and 18 t of alachlor enter the Gulf of Mexico from the Mississippi River annually as the result of mnoff (47). Field appHcation of pesticides inevitably leads to pesticide contamination of surface mnoff water unless mnoff does not occur while pesticide residues remain on the surface of the soil. The amount of pesticides transported in a field in mnoff varies from site to site. It is controUed by the timing of mnoff events, pesticide formulation, physical—chemical properties of the pesticide, and properties of the soil surface (48). Under worst-case conditions, 10% or more of the appHed pesticide can leave the edge of the field where it was appHed. 

Mono- and dichlorotoluenes ate used chiefly as chemical iatermediates ia the manufacture of pesticides, dyestuffs, pharmaceuticals, and peroxides, and as solvents. Total annual production was limited prior to 1960 but has expanded greatly siace that time. Chlorinated toluenes ate produced ia the United States, Germany, Japan, and Italy. Siace the number of manufacturers is small and much of the production is utilised captively, statistics covering production quantities ate not available. Worldwide annual production of o- and -chlorotoluene is estimated at several tens of thousands of metric tons. Yearly productions of polychlorotoluene ate ia the range of 100—1000 tons. 

The methods, which allow in one procedure of analysis to overcome, for example, most pesticides which are used in agricultural practice in the present time, get development and introduction in practice. The contribution of the Ukrainian scientists in field of chromatographic analysis of Persistent Organic Pollutants (POPs, chlorinated hydrocarbons, PCB s) and supertoxicants, such as PCDDs, is estimated. 

In 1974, the Harmonized Monitoring Programme was set up by the Department of the Environment (DoE). The objective was to provide a network of sites at the lower end of catchments, where water quality data could be collected and analysed in a nationally consistent manner, allowing the loads of materials carried through river catchments into estuaries to be estimated and long-term trends in river quality to be assessed. The complete list of substances to be monitored is diverse and specifies about 115 substances. The pesticides aldrin, dieldrin, y-HCH, heptachlor, p,p -DDT and p,p -DDE are included. Figures 1 and 2 show the downward trend of y-HCH and dieldrin over the past 20 years at the Harmonized Monitoring Sites. This confirms that reductions in environmental concentrations have been achieved, particularly over the past 10 years. 

Hawthorne, A., et al. (1987) Models for estimating organic emissions from building materials formaldehyde example. Atmos. Environ. 21, No. 2. Lewis, R. G., et al. (1986) Monitoring for non-occupational exposure to pesticides in indoor and personal respiratory air. Presented at the 79th Annual Meeting of the Air Pollution Control Association, Minneapolis, MN. 

Minimize disposal requirements by careful estimation of needs and correct measurement Dispose of dilute pesticides by using as a spray, in accordance with approval, in a safe/approved area Concentrated, unused pesticides should be stored, returned or disposed of as toxic waste... 

Furthermore, significant amounts of food are lost to pests. Worldwide preharvest crop losses to pests (insects, diseases, and weeds) are estimated to be about 35% each year (10). These major pest losses are occurring despite the application of about 2.5 million metric tons of pesticide, at an annual cost of 18 billion (11). Even after crops are harvested, an additional 20% of the food is lost to pests (12). Overall about 48% of all potential world food supply for humans is lost to pests despite all efforts to protect it. 

The total amount of pesticide applied worldwide, as mentioned, is estimated to be 2.5 million tons. Of this 50 to 60% are herbicides, 20 to 30% are insecticides, and 10 to 20% are fungicides. Interestingly, less than one-third of all the agricultural cropland in the world is treated with some kind of pesticide. This illustrates the fact that a significant portion of crops receive no pesticide and, therefore, are protected to some extent by nonchemical biological controls. 

A large number of domestic animals are poisoned each year by pesticides and must be destroyed. Additionally, significant amounts of meat and milk are contaminated with pesticides and must be removed from the market place (51). The yearly cost of these losses is estimated to be at least 30 million. 

When pesticides are applied to crops, many natural enemies that help control pests are destroyed (37). This causes pest outbreaks that subsequently are controlled with additional pesticide applications. The control of such pest outbreaks is estimated to cost at least 520 million each year. 

As pesticides are applied, large numbers of honey bees and wild bees are poisoned resulting in not only a diminished honey crop, but perhaps more important, reduced crop pollination that is vital to agricultural production (51). The estimated yearly cost of reduced pollination and reduced honey production is about 230 million (Pimentel, D., in manuscript). 

Some pesticides, especially when applied by aircraft, drift into adjacent agricultural lands where they may damage crops. This type of destruction is estimated to cost at least 900 million... 

From this analysis it is clear that in addition to their benefits, the use of pesticides in food production not only causes serious public health problems but also considerable damage to vital agricultural and natural ecosystems in the United States and world. A conservative estimate suggests that the environmental and social costs of pesticide use in the United States total about 4 billion each year. Worldwide the yearly environmental and public health costs are probably at least 100 billion. This is several times the 18 bllllon/yr spent on pesticides in the world. 

Of major concern are the health and environmental impacts of the abundant chlorinated and brominated hydrocarbons (ref. 2). These materials have numerous industrial applications as pesticides, solvents, propellants, refrigerants, plastics, fire retardants and extinguishers, disinfectants for drinking water, pharmaceuticals and electronic chemicals. Many chemical manufacturers utilize chlorinated and brominated organics as intermediates. It is estimated, for instance, that almost 85 % of the pharmaceuticals produced in the world require chlorine at some stage of synthesis. 

Data from ORTEPA (2002) (biocides, pesticides, synthesis, and giass coating), ESPA (2002) (PVC stabiiizers), and ETiCA (2002) (cataiysts), as updated by ETiNSA (2003). Exciudes use as a biocide in antifouiing paints, which was estimated at over 1250 tonnes per year (but is rapidiy deciining as the internationai ban is impiemented). 

Methyl parathion is approved only for use on crops. The maximum amount of methyl parathion residue allowed by the Food and Drug Administration (FDA) and EPA on crops used as food is 0.1-1 ppm. The FDA has monitored the food supply for pesticides for a number of years. FDA purchases many kinds of foods through Market Basket Surveys and analyzes them for residue levels of pesticides. These FDA studies allow scientists to estimate the daily intake of pesticides. Generally, the FDA monitoring studies conclude that the U.S. food supply contains only very small amounts of pesticides that are not a concern. However, there have been some reports of the illegal use of methyl parathion inside homes. For more information, see Section 1.7 and Chapter 6. 

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