Environmental Fate and Transport of Pesticides - Pesticides: Evaluation of Environmental Pollution - page 29

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Environm ental Fate and Transport of Pesticides
Jie Gao, Yu Wang, Bin Gao, Lei Wu, and Hao Chen
CONTENTS
2.1 Introduction .......................................................................................................................... 29
2.2 Source .................................................................................................................................... 30
2.3 Fate and Transport............................................................................................................... 30
2.3.1 Transformation and Degradation.......................................................................... 30
2.3.1.1 Abiotic Degradation.................................................................................. 31
2.3.1.2 Biodegradation (Biotic Degradation)...................................................... 33
2.3.2 Sorption and Desorption ........................................................................................ 34
2.3.3 Volatilization............................................................................................................. 35
2.3.4 Uptake by Plants ...................................................................................................... 36
2.3.5 Surface Runoff .......................................................................................................... 36
2.3.6 Leaching Through the Soil Profile ........................................................................ 37
2.4 Transport Models................................................................................................................. 38
2.4.1 HERBSIM and SIMULAT Models ......................................................................... 38
2.4.2 HYDRUS Model ....................................................................................................... 38
2.4.3 Leaching Estimation and Chemistry Model........................................................ 39
2.4.4 MACRO Model......................................................................................................... 39
2.4.5 Root Zone Water Quality Model ........................................................................... 39
2.4.6 Studio of Analytical Models................................................................................... 39
2.4.7 Saturated-Unsaturated Transport Model ............................................................ 39
2.4.8 Model Application ................................................................................................... 40
References....................................................................................................................................... 41
2.1 Introduction
Pesticides are biologically active substances used for preventing, destroying, or controlling
pests by interfering with their metabolic processes (Rice et al. 2007). For decades, pesti-
cides have been used for preventing diseases transmitted by pests such as mosquitoes and
fleas in humans and animals, increasing food production by destroying insects and other
pests in agricultural areas, and protecting the environment by controlling the growth of
molds, weeds, and algae (Whitford 2006). For example, it was found that rice production
was reduced by at least 10% without the use of pesticides (Kuniuki 2001).
Clearly, pesticides are playing an important role in improving the quality of our daily life;
however, in recent years, there have been continuing concerns about and research on the
adverse impacts of pesticides and their degradation products on public health and the envi-
ronment. Frequent detections of pesticides and their degradation products in surface waters
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