Pesticide levels and environmental risk in aquatic environments in China — A review

Abstract

China is one of the largest producers and consumers of pesticides in the world today. Along with the widespread use of pesticides and industrialization, there is a growing concern for water quality. The present review aims to provide an overview of studies on pesticides in aquatic environments in China. The levels in the water, sediment and biota were scored according to a detailed environmental classification system based on ecotoxicological effect, which is therefore a useful tool for assessing the risk these compounds pose to the aquatic ecosystem. Our review reveals that the most studied areas in China are the most populated and the most developed economically and that the most frequently studied pesticides are DDT and HCH. We show maps of where studies have been conducted and show the ecotoxicological risk the pesticides pose in each of the matrices. Our review pinpoints the need for biota samples to assess the risk. A large fraction of the results from the studies are given an environmental classification of "very bad" based on levels in biota. In general, the risk is higher for DDT than HCH. A few food web studies have also been conducted, and we encourage further study of this important information from this region. The review reveals that many of the most important agricultural provinces (e.g., Henan, Hubei and Hunan) with the largest pesticide use have been the subject of few studies on the environmental levels of pesticides. We consider this to be a major knowledge gap for understanding the status of pesticide contamination and related risk in China. Furthermore, there is also a lack of studies in remote Chinese environments, which is also an important knowledge gap. The compounds analyzed and reported in the studies represent a serious bias because a great deal of attention is given to DDT and HCH, whereas the organophosphate insecticides dominating current use are less frequently investigated. For the future, we point to the need for an organized monitoring plan designed according to the knowledge gaps in terms of geographical distribution, compounds included, and risks.

Insecticides in sediment cores from a rural and a suburban area in South China: A reflection of shift in application patterns

“…Though the use of these legacy compounds was banned in the early 1980s, HCHs and DDTs were detected at all sediment depths in SGZ and accounted for a large proportion of the OCPs present in the core (30.5 ± 7.5% and 60.9 ± 8.1% of ΣOCP, respectively). The high detection frequency of HCHs and DDTs in the SGZ core is supported by other studies in South China (Guo et al, 2009;Grung et al, 2015). It was assumed that the same trends would be observed for the RLY core as well, however surprisingly, that was not the case, as HCHs and DDTs were rarely detected in the core, and rather chlordanes were detected at higher concentrations (11.2-98.8 ng/g) and dominated the OCP composition (84.2% ± 10.2%).…”

Wettability of pear leaves from three regions characterized at different stages after flowering using the OWRK method

“…Because of frequent pest and disease outbreaks, the entire cultivation and management process requires a large amount of pesticide application. If not correctly applied and if the maximum recommended dose rate is not respected, this not only leads to pesticide residues exceeding the standard, but also contaminates the environment . To improve the retention and spreading of the spray liquid on the target surface, the wettability of pear leaves from different ecological environments at different growth stages needs to be studied.…”

“…If not correctly applied and if the maximum recommended dose rate is not respected, this not only leads to pesticide residues exceeding the standard, but also contaminates the environment. 37 To improve the retention and spreading of the spray liquid on the target surface, the wettability of pear leaves from different ecological environments at different growth stages needs to be studied. In this study, Yuanping City, Yuci City and Linyi County in Shanxi Province, all with different climates (Table 1), were selected to study surface wettability of pear leaves, and to establish a scientific and rational agrochemical application technique.…”

A refined method for analysis of 4,4′-dicofol and 4,4′-dichlorobenzophenone

“…A number of studies have shown that 1,1-dichloro-2,2-bis(4-chlorophenyl) ethane (4,4′-DDE), the major metabolite of 1,1′-bis(4-chlorophenyl)-2,2,2-trichloroethane (4,4′-DDT), is present at high levels in different environmental media in China (Grung et al 2015; Yin et al 2015; Zhang et al 2013; Zhou et al 2016a) even though technical DDT was prohibited for agricultural use in 1983 (Yu et al 2005). Qiu et al (2005) stated that the use of dicofol in China has become an important source of DDT after the prohibition.…”