Pesticides environmental impact

Many factors affect the mechanisms and kinetics of sorption and transport processes. For instance, differences in the chemical stmcture and properties, ie, ionizahility, solubiUty in water, vapor pressure, and polarity, between pesticides affect their behavior in the environment through effects on sorption and transport processes. Differences in soil properties, ie, pH and percentage of organic carbon and clay contents, and soil conditions, ie, moisture content and landscape position climatic conditions, ie, temperature, precipitation, and radiation and cultural practices, ie, crop and tillage, can all modify the behavior of the pesticide in soils. Persistence of a pesticide in soil is a consequence of a complex interaction of processes. Because the persistence of a pesticide can govern its availabiUty and efficacy for pest control, as weU as its potential for adverse environmental impacts, knowledge of the basic processes is necessary if the benefits of the pesticide ate to be maximized. 

Until recently, the NRA has not participated during the approval process in assessing the potential environmental impact of pesticides. However, the NRA does supply monitoring data to MAFF and HSE for pesticide reviews. These occur once a pesticide has been approved for use for a certain length of time, or when further information is needed on an approved pesticide. In supplying these data, the NRA comments on any areas of concern. This contributed to the 1993 ban on the use of atrazine and simazine on non-cropped land. In January 1995 the NRA s National Centre for Toxic and Persistent Substances (TAPS) was made advisor to the DoF, on the potential impact on the aquatic environment of... 

The main purpose of pesticide formulation is to manufacture a product that has optimum biological efficiency, is convenient to use, and minimizes environmental impacts. The active ingredients are mixed with solvents, adjuvants (boosters), and fillers as necessary to achieve the desired formulation. The types of formulations include wettable powders, soluble concentrates, emulsion concentrates, oil-in-water emulsions, suspension concentrates, suspoemulsions, water-dispersible granules, dry granules, and controlled release, in which the active ingredient is released into the environment from a polymeric carrier, binder, absorbent, or encapsulant at a slow and effective rate. The formulation steps may generate air emissions, liquid effluents, and solid wastes. 

In this chapter, the agricultural, economic, and environmental impacts of pesticide use in world and U.S. food production are analyzed. In addition, an assessment is made of the potential that substituting nonchemical controls for some pesticide use would have in reducing chemicals and providing adequate pest controls. 

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. 

EPA. 1974b. Production, distribution, use, and environmental impact potential of selected pesticides [final report]. Washington, DC U.S. Environmental Protection Agency, Office of Pesticide Programs. EPA 540/1-74-001, 181-188. 

Selective toxicity is also important in relation to the development of resistance or tolerance to pollutants from two distinct points of view. On the one hand, there is interest among scientists concerned with crop protection and disease control in mechanisms by which crop pests, vectors of disease, plant pathogens, and weeds develop resistance to pesticides. Understanding the mechanism should point to ways of overcoming resistance, for example, other compounds not affected by resistance mechanisms or synergists to inhibit enzymes that provide a resistance mechanism. On the other hand, the development of resistance can be a useful indication of the environmental impact of pollutants. 

Climatic fluctuations, long-term usage trends and agronomic practices can dramatically affect the characteristics of the monitoring data obtained from a field study, and this in turn affects the degree to which the study can be utilized to generalize about the environmental impacts of use of the pesticide. Surface water programs should be multi-year studies if one intends to address adequately the variability of pesticide... 

Further, the authors have carefully examined and documented the public health and environmental impacts of pesticide use in the USSR. The USSR was the largest country by territory in the world and the use of pesticide here was enormous. As the authors have shown, this happened mostly because the USSR s Communistic rulers decided at the end of the 1960 s — to turn all chemical weaponry plants (constructed in the beginning of the cold war) to pesticide production. With rich government subsidies, pesticides were distributed through all collective farms The Soviet official policy, the chemicalisation of agriculture, was an attempt to overcome its prominent ineffectiveness in crop production. 

The growing concerns about the public health and environmental impacts of pesticides have led many in the general public and the government to question whether all the benefits of pesticides, such as the perfect red apple, are worth the associated costs of environmental pollution, human illness and loss of life, bird kills, and the destruction of other beneficial natural organisms. Indeed, some agriculturists have been viewed as primarily concerned with promoting commercial interests rather than protecting public health and the environment. 

In Tables 14.9 and 14.10, the last column reports the environmental impact points (EIPs) for typical applications of organic and conventional pesticides derived from the Pesticide Environmental Assessment System, or PEAS. This model produces relative rankings of risks based on defined use rates and use patterns (the formulation used to apply a pesticide, timing, target of the application, spray equipment used, etc). PEAS scores reflect an equal balancing of acute pesticide risks to farm workers, chronic risks via dietary exposure and exposures to birds, Daphnia and bees. 

Thirugnanam, M. and A.J. Forgash. 1977. Environmental impact of mosquito pesticides toxicity and anticholinesterase activity of chlorpyrifos to fish in a salt marsh habitat. Arch. Environ Contam, Toxicol. 5 415-425. Tsuda, T., S. Aoki, T. Inoue, and M. Kojima. 1994. Accumulation and excretion of pesticides used as insecticides or fungicides in agricultural products by the willow shiner Gnathopogon caerulescens. Comp. Biochem. Physiol. 107C 469-473. 

Kovach J, Petzoldt C, Degni J, Tette J (1992) A method to measure the environmental impact of pesticides. New York Food Life Sci Bull 192 2-8 Kropff MJ, Bouma J, Jones JW (2001) System approaches for the design of sustainable agroecosystems. Agric Sys 70 369-393... 

Pimentel D (1995) Amounts of pesticides reaching target pests environmental impacts and ethics. J Agric Env Ethics 8 17-29... 

Due to the environmental impact of pesticides, several priority lists have been published to help protect the quality of drinking and surface waters. Table 4 lists the different pesticides from the 76/464/EC Directive (i. e., the so-called black list [168, 171-174]). Following the three general parameters (toxicity, persistence, and input) for selecting the priority list of pollutants in the United Kingdom, a red-list of substances that include several pesticides, most of them common to the EC list, was established. 

Rao, P.S.C. and Davidson, J.M. Estimation of pesticide retention and transformation parameters required in nonpoint source pollution models, in Environmental Impact of Nonpoint Source Pollution, Overcash. M.R. and Davidson, J.M., Eds. (Ann Arbor. MI Ann Arbor Science Publishers. 1980), pp. 23-67. 

There are a few companies that are hoping to change this. Several chemical companies that already have a large share of the chemical pesticide market are actively screening fermentation broths. A major motivation for this probably comes from the present concern about our environment. There is a perception that "natural pesticides will have a much less serious environmental impact than "chemicals". Whether this advantage is real or only psychological remains to be seen. 

Spencer, W. F., M. M. Cliath, and S. R. Yates. Soil-pesticide interactions and their impact on the volatilization process, in Environmental Impact of Soil Component Interactions—Natural and Anthropogenic Organics, Vol. 1, CRC Press, Boca Raton, FL, 1995, pp. 371-381. 

Variability and uncertainty affect every element of every risk assessment. For example, participants in the European Workshop on Probabilistic Risk Assessment for the Environmental Impacts of Plant Protection Products (EUPR A) were asked to list sources of uncertainty affecting current procedures for assessing pesticide risks to aquatic... 

New adverse environmental impacts will continue to be found, even with some of the substitutes. In some cases, biodegradable substitutes might be possible. The search for alternative pesticides or other products that have less adverse environmental impact has been rewarding to society and industry. Such efforts need to be continued and will be driven by the marketplace s responding to public and government interests. 

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