**1. Introduction**

410 Pesticides in the Modern World - Risks and Benefits

Baxtor, R.M, 1990; Reductive dechlorination of certain chlorinaud organic compounds by

Chiras, Daniel D, 2000 *Environmental Science, Creating a Sustainable future*, 6th Edition, Denver

Chen, W.Q., Zhang, L.P, Xu, L., Wang.X.H., Hong, H.S.,1996. Concentrations and

Sanders, G. 1993 Long-term Temporal Trends of PCBs and PAHs in the environment and their Behaviour in Lacustrine Systems. PhD Thesis, University of Lancaster. Sierra Club of Canada; Pesticides Fact Sheet, *The Journal of National Coalition Against the use of* 

Venkatesan M.I, de Leon R.P, van Geen A, Luoma S.N, 1998; Chlorinated hydrocarbon

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21.451-458.

Ness

*Pesticides*, 1998

Bay, California, USA.

University, Colorado, USA

reduced 1mmh compared with their behaviour in the environment. *Chemosphere*

distributions of HCHs,DDTs and PCBs in surface sediments of sea area between Xiamen and Jinmen. *Journal of Xiamen University. Natural Science 35 (6) 936±940*  Sanders, G., Jones, K.C., Hamilton-Taylor, J., and Dorr, H. (1992). Historical inputs of

polychlorinated biphenals and other organochlorines to a dated lacusrine Vol 105; The Scottish Naturalist: Use of a Sediment Core: Historical Contaminants to Loch

pesticides and polychlorinated biphynals in sediment cores from San Francisco

Pesticides are poisons designed to kill pests such as rodents, insects, weeds and fungi. Pesticides are, by their nature, toxic chemicals; since many pesticides may potentially leave residues on foods available for human consumption, there is much concern regarding the potential health risks of pesticides in the human diet. Pesticides used in agriculture to control pests, such as insects, weeds, and plant diseases, have been subject to considerable legislative, regulatory, and consumer scrutiny over the past few decades. Pesticides, with their high degree of toxicity, constitute a very important group of target compounds in environmental samples. Those presentnin waters may have an agricultural, domestic or industrial origin, the most harmful effect being their inclusion in the so-called "nutritionchain" (Vinas et al., 2002). Many common pesticides contain potent neurotoxic chemicals that attack and disable portions of the nervous system and brain. The use of pesticides in commercial agriculture has led to an increase in farm productivity (Guler et al., 2010). Pesticides also present environmental concerns including water and soil contamination, air pollution, destruction of natural vegetation, reductions in natural pest populations, effects upon non-target organisms including fish, wildlife, and livestock, creation of secondary pest problems, and the evolution of pesticide resistance (Winter, 2004). Many pesticides were used on a global scale from the 1950s to the mid-80s, most of which are stable and persistent in the environment (Barra et al., 2001).

The use of pesticides in agriculture is necessary to combat a variety of pests that could destroy crops and to improve the quality of the food produced. The advantages and disadvantages of pesticide pollution controlling technique are determined by many factors, which require a comprehensive evaluation method adopted in the evaluation of pesticide pollution controlling techniques. Exposure to high levels of pesticides can cause a range of acute, flu- and malaria-like symptoms including headaches, weakness, nausea, respiratory distress, convulsions, coma, and death, accounting for an estimated 20,000 fatalities per year (Jiang and Wan, 2009; Guler et al., 2010).

In a recent USEPA summary report defined vulnerability applied to risk assessment as a four component system: (1) susceptibility or sensitivity of the human or ecological receptors; (2) differential exposures of the receptors; (3) differential preparedness of the receptor to withstand the insult from exposure; (4) differential ability to recover from these effects. All of these components are pertinent to systems undergoing development from the fetus

Pesticides and Their Movement Surface Water and Ground Water 413

DDT Endrin Aldrin Dieldin Endosulfan α-, β-, γ-,

Malathion Fenitrothion Dichlorvos Diazinon Carbaryl Aldicarb

Pyrethrum Permethrin Cypermethrin Flumethrin

Abamectin Ivermectin Rotatone Nicotine

Cyromazine Diflubenziron Tebufenozite

Amitraz Fibronil

Hexachlorocyclohexane

Organophophates (Ops)

Juvenile hormone analogues Chitin synthesis inhibitors

adsorption include pesticide charge; soil pH, temperature and water content; the presence of previously adsorbed chemicals that have a stronger bond to soil particles; and the amount and type of organic matter present. In general, pesticide adsorption relates inversely to pesticide solubility in water. Highly soluble pesticides are weakly adsorbed and pose a

Four chemical properties that affect pesticide movement are solubility, adsorption, volatility

**Solubility:** The tendency of a pesticide to dissolve in water affects its leaching potential. As water seeps downward through soil, it carries with it water- soluble chemicals. This process is called leaching. Water solubility greater than 30 mg/L has been identified as the flag for a

Ecdysone agonists

Formamidine GABAA blocker

Group Subgroups Examples

Carbamates

Organochlorines

Anticholinesterases

Pyrethrins and synthetic

Natural compounds, other

Substances which interfere

Miscellanous synthetic

Table 1. The Main classes of Pesticides

greater threat of groundwater contamination.

Pyrethroids

than pyrethrins

with system specific to insect

insecticides

and degradation.

through childhood. For example, differences in the chemical biotransformation capacity of the human fetus and developing child can be both protective and potentially detrimental to normal development Regarding this point, there is little direct information regarding the specific metabolism of xenobiotics, much less pesticides, in children or the fetus. Overriding differences in biotransformation in the fetus is the probable role of maternal metabolism of xenobiotics affecting the level of fetal toxicant exposure. Polymorphisms of maternal phase 1 and phase 2 enzymes may play a key role in these exposure events (Garry, 2004).

Deterioration of surface and ground water quality represent the most significant adverse environmental impact associated with agricultural production. Degradation of surface and ground water quality has been identified as the primary concern with respect to the impact of agriculture on the environment. The degradation may occur as a result of the leaching of agricultural chemicals soil or biological organisms to surface waters. In this study, it is evaluated the surface and ground water contamination by pesticides.
