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Concentration, characterization and risk assessment of polycyclic aromatic hydrocarbons and organochlorine pesticides in soils from the Corn Belt of northeast China
Author(s) -
Wang Zucheng,
Liu Shasha,
Lu Kaijun,
Xu Xiaoyun,
Zhang Tianyu
Publication year - 2020
Publication title -
european journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 1351-0754
DOI - 10.1111/ejss.12915
Subject(s) - environmental chemistry , soil water , chemistry , contamination , total organic carbon , lindane , organic matter , pesticide , biomass (ecology) , hexachlorocyclohexane , persistent organic pollutant , environmental science , pollutant , agronomy , soil science , ecology , organic chemistry , biology
Organic contaminants in agricultural soils are widely reported; however, their accumulation patterns are quite different among regions. This study reports the distribution, accumulation and risk assessment of polycyclic aromatic hydrocarbons (PAHs), dichlorodiphenyltrichloroethane (DDT) and hexachlorocyclohexane (HCH) in soils from the Corn Belt of northeast China at a regional scale. Concentrations of PAHs, DDT and HCH were 306‐5300, 6.00–82.0 and 4.07–15.6 ng g −1 , respectively. Source analysis suggests PAHs were derived from regional combustion of biomass and coal, except where sites are strongly affected by local sources. The DDT and HCH residues in soils are likely to be derived from previous agricultural applications that have persisted due to slow microbiological degradation under low mean temperatures. Precipitation was only significantly correlated with PAH concentrations, suggesting that precipitation affected PAH but not DDT and HCH distributions at a regional scale. Positive correlations between DDT concentrations and total organic carbon (TOC) contents of soils suggest hydrophobic organic contaminants were associated with organic matter. In contrast, TOC contents were correlated with PAHs in alfisols but not in pedocals. Pedocals contained mainly high molecular weight PAHs, indicating that eluviation affected the accumulation of less hydrophobic organic contaminants. Different correlations between low‐molecular‐weight PAH and HCH concentrations with TOC contents were found in alfisols, suggesting that contaminant structure may also affect the accumulation of less hydrophobic organic contaminants in these soils. Risk analysis suggested that potential ecological risks related to soils in the Corn Belt may lead to reduced maize production and the potential for human health risks in the future. Highlights Few studies focus on regional‐scale factors that affect organic contaminant accumulation in soils. Environmental process affects less hydrophobic organic contaminant distribution at regional scale. Precipitation and eluviation affected accumulation of less hydrophobic contaminants in soils. PAH and OCP residues in the soil of maize fields may pose ecological risks affecting future crop production and human health.