Environmental effects pesticides

Examples of Synthesis Routes Inherently Safer Than Others As summarized by Bodor (1995), the ethyl ester of DDT is highly effective as a pesticide and is not as toxic. The ester is hydrolytically sensitive and metabolizes to nontoxic products. The deliberate introduction of a structure into the molecule which facilitates hydrolytic deactivation of the molecule to a safer form can be a key to creating a chemical product with the desired pesticide effects but without the undesired environmental effects. This technique is being used extensively in the pharmaceutical industry. It is applicable to other chemical industries as well. 

In addition to poisoning humans, pesticides affect agricultural ecosystems and spread beyond into surrounding terrestrial and aquatic ecosystems. As a result, detrimental environmental effects follow pesticide use in the United States. Some of these are delineated below ... 

Cooke, A. (1988). Poisoning of woodpigeons on Woodwalton fen. M.P. Greaves, B.D. Smith, and P.W. Greig-Smith (Eds.) Field Studies for the Study of the Environmental Effects of Pesticides. BCPC Monograph No. 40, Thornton Heath, U.K. British Crop Protection Council, 297-301. 

FIFRA23 imposes a system of pesticide product registrations. Such requirements include premarket review of potential health and environmental effects before a pesticide can be introduced in the United States, reregistration of products introduced prior to the enactment of FIFRA to assess their safety in light of current standards, and classification of pesticides for restricted or general use. Restricted products can be used only by those whose competence has been certified by a state program. 

The first sereen is toxieity and environmental effects of the compounds. Table 1 shows the relative value of toxieities for several different types of industrial eompounds and for several ehemical warfare agents, and eompares them to some eommon industrial pesticides and chemicals. 

My son worked at a country club north of here, and I saw what they did. They were putting diazinon on. It rained, and it killed all of the ducks at the country club. The country club didn t want anyone to know about it, so they hired him [Walter s son] to put them all in a dump truck and take them away. And I m thinking, geez, you know there s some really horrible environmental effects here. Obviously, if it kills ducks, it kills fish too. It says that on the bag [of pesticide], but you know you don t pay much attention to that. StiU, it goes down the drain. I want a nice looking lawn, but I don t want to endanger any [wildlife]. 

Parathion, a heavily-used pesticide with strongly adverse environmental effects, is a member of the phosphoric acid esters group with a general formula of the type... 

Besides the environmental effects of greenhouse gases, agriculture also contributes to air contamination by ammonia volatilisation (NH3) and pesticide sprays. Therefore, this section is entitled "climate and air", and focuses on the greenhouse gases CO2, N2O and CH4, as well as on NH3 and pesticide sprays. 

NPTN is based at Oregon State University and is cooperatively sponsored by the University and EPA. NPTN serves as a source of objective, science-based pesticide information on a wide range of pesticide-related topics, such as recognition and management of pesticide poisonings, safety information, health and environmental effects, referrals for investigation of pesticide incidents and emergency treatment for both humans and animals, and cleanup and disposal procedures. 

Several widely used pesticides are highly chlorinated polycyclic compounds derived from hexachloropentadiene. They include Aldrin, Dieldrin, and Chlordane. Use of these substances is to be curtailed greatly because of undesirable environmental effects. 

Generally, it takes some five to seven years to bring a pesticide to market once its pesticidal properties have been verified. Many tests must be conducted to determine such things as the compound s synthesis, its chemical and physical properties, and its efficacy. In addition, in order for registration for use by the US EPA, numerous toxicity tests are undertaken including those for acute toxicity, those for chronic effects such as reproductive anomalies, carcinogenesis, and neurological effects and those for environmental effects. 

This section has covered only a few of the pesticides available today on the United States and world markets. An understanding of the basic chemical processes affected by pesticides has led to the discovery and production of new families of chemicals. Today s modem pesticide is generally safe to use if the directions on the label are followed. Advances in instrumentation and an understanding of how adverse health effects are produced have resulted in the production of many environmentally friendly but effective pesticides. 

Neary, D.G., P.B. Bush, and J.L. Michael (1993). Fate, dissipation, and environmental effects of pesticides in southern forests A review of a decade of research progress. Environ. Toxicol. Chem., 12 411—428. 

The peak period for the use of aldrin and dieldrin was between the late 1960s and the early 1970s throughout various parts of the world (WHO, 1989). The use pattern of aldrin and dieldrin are quite similar. They act as effective contact and stomach poisons for insects. They are used to control soil insects (e.g. grasshoppers and corn rootworm), and protect crops and wooden structures from termites (WHO, 1989). The production of aldrin and dieldrin has decreased since the early 1960s. In the United States, the peak use of aldrin from 19 million pounds in 1966 decreased to 10.5 million pounds in 1970 (USEPA, 1980). During this same period (1966-1970), annual dieldrin use dropped from 1 million to 670,000 pounds. These decreases were primarily due to increased insect resistance to the aldrin and dieldrin, and to the development and availability of more effective and environmentally friendly pesticides (USEPA, 1980). 

US Environmental Protection Agency [USEPA], Office of Pesticide Programs, Environmental Fate and Effects Division. 2001. Environmental effects database (EEDB). ECO-TOX Database System, http //www.epa.gov/ecotox/ (accessed July 23, 2005). 

What are the environmental effects of this heavy use of pesticides (insecticides and herbicides) After heavy rains on the island, large numbers of dead fish have been found in the ocean, and washed up on the shore near the potato farms. The suspected cause is the leaching of sodium arsenite and other pesticides used in the potato fields. Sodium arsenate is a chemical used to kill both weeds and insects. If the poisoning of the ocean waters continues, Prince Edward Island s unique seafood industry will come to an end. 

From these data on pesticide usage, the environmental effects associated with adoption of GM crops will be assessed both qualitatively and quantitatively. Qualitatively, the impact will be predicted based on, for example, properties of pesticides, quantities of applied pesticides, times of application, pest characteristics, and geographic conditions. Subsequently, the quantitative assessment will employ methods such as environmental indicators that allow for a comparison of the environmental impacts of different pesticide regimes. The enviroiunental impact may also cover other important parameters associated with altered agronomic practices under GM crop cultivation, such as tillage practices and farmland biodiversity. 

To allow for comparison of the environmental effects of pesticides, various tools have been developed to express these effect(s) in quantifiable terms. One example is the Environmental Impact Quotient (EIQ) developed by Kovach and co-workers [19]. The aim of the EIQ is to transform information on the toxicological and environmental impacts of pesticides into a usable format to facilitate the choice which pesticide to apply in practice. For each pesticide, the EIQ value is based on an equation which brings together mode of action, environmental behavior, and toxicity to humans, animals, and wildlife. To calculate the environmental impact of fee application of a certain pesticide, its EIQ is multiplied with the application dose (applied amount of active ingredient). To date, EIQs are available for more than 200 pesticides, including chemical and organic pesticides (see website under reference [19]). 

The last chapter. Chapter 9, discusses the environmental effects of pesticides. The topics covered include sources of contamination, pesticide fate and transport, and endangered species. 

---