Comparative study on the pollution status of organochlorine pesticides (OCPs) and bacterial community diversity and structure between plastic shed and open-field soils from northern China

To reveal the pollution status of agricultural soils along with rapid urbanization and economic growth, a large regional survey of organochlorine pesticides (OCPs) in agricultural soils was conducted in the Pearl River Delta (PRD) of China. The results showed that the total residues of 23 OCPs were in the range of ND-946 ng/g dry weight. OCP residues showed distinct spatial distribution characteristics within the PRD. OCPs were mainly found in areas with high agricultural production and industrial activities. Higher OCP concentrations were observed in the top layer of soil, while the concentration decreases to marginal levels when the soil depth is greater than 50 cm. OCPs are mainly derived from historical use. Hexachlorocyclohexanes(HCHs) in the top soil of the study area are mainly from the use of lindane. Soil pH was negatively and significantly correlated with total OCP concentration. The human health risk assessment showed no health risk for children, while for adults, there is a non-carcinogenic risk, which needs to be noticed. Agricultural activities and industrial production have made the region a pollution hotspot and should arouse more stringent regulation to protect the environment and food safety.

Section: Resultssupporting

confidence: 90%

Levels, Distribution and Health Risk Assessment of Organochlorine Pesticides in Agricultural Soils from the Pearl River Delta of China

Yao

Huang²,

Zhou³

et al. 2022

“…Among these compounds, δ-HCH was generally the most dominant, with concentrations ranging from n.d. to 0.78 ng/L, with a mean value of 0.223 ng/g at a 60% detection frequency of the soil samples. Compared with other regions, the pollution levels of HCHs in agricultural soils in Xiamen were lower than those in northern regions (34.0 ng/g) [20], central regions (15.39 ng/g) [21], Shanghai (2.41 ng/g) [22], Zhangzhou (9.79 ng/g) [23], Qinghai-Tibet Plateau (0.35 ng/g) [24], and other countries such as South Korea (0.2 ng/g) [25]; they were higher than in Kuwait (0.065 ng/g) [26] and Mexico (0.027 ng/g) [27]. Dichlorodiphenyltrichloroethane (DDT) is converted into Dichlorodiphenyldichlor oethane (DDD) and Dichlorodiphenylethane (DDE), respectively under anaerobic and aerobic conditions, and their derivatives include o, p -DDT, which is made from a racemic mixture of enantiomers (1:1) [28].…”

Section: General Situation Regarding Agricultural Soil (Distribution ...mentioning

confidence: 69%

Distribution Characteristics and Influencing Factors of Organochlorine Pesticides in Agricultural Soil from Xiamen City

Gao

Chen

Qin

et al. 2023

The concentration and distribution of 15 organochlorine pesticides in the soil of Xiamen City were determined. Overall, among the 15 selected target pesticides, 14 organochlorine pesticides (OCPs) were detected (hexachlorobenzene was not). The range of detected pesticides was undetected−10.04 ng/g, the total detection rate was 35.2%, and the three pollutants with the highest detection rate in all samples were Heptachlor (66.7%), δ-Hexachlorocyclohexane (60.0%), and p, p′-Dichlorodiphenyldichloroethane (58.3%). The degree of pollution in descending order was Tong’an > Xiang’an > Jimei > Haicang. Linear regression analysis of soil properties and OCP concentration distribution revealed that OCPs were positively correlated with water content, dissolved organic carbon, and pH and negatively correlated with cation exchange capacity. The origin of OCPs was evaluated using the relationship between the parent compound and its metabolites, with possible new hexachlorocyclohexane and isomer (HCHs) input. By comparing the risk screening values of ΣHCHs and ΣDDTs in “Soil Environmental Quality Standards”, the concentrations in all soil samples were lower than the standard values, which indicated that the OCP residues in Xiamen were very low.

“…β -HCH is the most difficult of the HCHs isomers to degrade due to its own special structure that all chlorine atoms are in the carbon frame plane [ 29 ]. Meanwhile, the ratio of β -HCH/( α -HCH + γ -HCH) in all water bodies in this study is much greater than 0.5, indicating that there has been no new input of HCHs and lindane ( γ -HCH) in surface waters of these crop production areas in the recent past [ 33 ]. For DDTs ( Figure 2 D), pp’ -DDE contents were more than 50% in all four crop production areas waters, followed by pp’ -DDT contents in the range of 10–30% in each crop production areas water.…”

Section: Resultsmentioning

confidence: 99%

Analysis of Pollution Characteristics and Sources in Surface Water in Typical Crop-Producing Areas of Qinghai Province

Chen

et al. 2022

Self Cite

Currently used pesticides and organochlorine pesticides (OCPs), nitrogen and phosphorus were analyzed in surface water from 26 sampling sites of agricultural areas in Qinghai Province to elucidate their pollution characteristics and sources. The results showed that most of these currently used pesticides, with the exception of chlorpyrifos, were generally not detected. However, two OCPs were commonly detected in surface water from four typical crop-producing areas. The residual concentrations of hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) measured 0~1.68 ng/L and 0.41~2.41 ng/L, respectively, in the water from the four crop-producing areas. The residues of these two OCPs pesticides were much lower than the standard limit of surface water environmental quality. The main forms of HCHs and DDTs were β-HCH and pp’-DDE, respectively, indicating that the residues of HCHs and DDTs in the surface water of the four crop-producing areas in Qinghai were mainly derived from historical drugs that had degraded for a long time. The average concentrations of TN, NO3−-N and NH4+-N in the surface water of 26 sampling sites of four typical crop areas in Qinghai Province were 2.95, 1.71 and 0.17 mg/L, respectively. According to the national surface water environmental quality standards, TN concentrations in 57.7% of these sampling sites exceeded the Class V water standards. The average concentration of NO3−-N was more than 70 times that of NH4+-N. Nonetheless, there were no significant differences in the concentrations of TN, NO3−-N and NH4+-N in the four crop-producing areas. The concentrations of NO3−-N and NO3−-N in the surface water were positively correlated with the TN concentration (p < 0.05), indicating that the sources of nitrogen in the surface water were relatively consistent. The average value of TP concentrations in the surface water from these sampling sites was 0.034 mg/L, with no significant differences among different producing areas. The N/P values in surface water from the four crop-producing areas of Qinghai Province had a range of 9.2~302. Phosphorus was the limiting factor for the proliferation of plankton in water. Reducing the input of phosphorus in these areas may be the key to preventing the deterioration of water quality. Significant negative and positive correlations exist between HCHs and nitrate nitrogen, and total phosphorus, respectively, which may be attributed to the proliferation of degrading microorganisms caused by the eutrophication of water. The research results will help to identify the characteristics and sources of surface water pollution in the crop-producing areas of Qinghai Province, and provide data support for Qinghai Province to build an export area for green organic agricultural and livestock products.