Distribution patterns of phthalic acid esters in soil particle-size fractions determine biouptake in soil-cereal crop systems.

Wenbing Tan,Rutai Gao,Caihong Huang,Beidou Xi,Akram N Alshawabkeh,Dongyu Cui,Dan Li,Yuan Zhang,Xiaosong He,Hui Zhang,Qiong Liang,Xuhui Mao

doi:10.1038/srep31987

Abstract

The use of wastewater irrigation for food crops can lead to presence of bioavailable phthalic acid esters (PAEs) in soils, which increase the potential for human exposure and adverse carcinogenic and non-cancer health effects. This study presents the first investigation of the occurrence and distribution of PAEs in a maize-wheat double-cropping system in a wastewater-irrigated area in the North China Plain. PAE levels in maize and wheat were found to be mainly attributed to PAE stores in soil coarse (250–2000 μm) and fine sand (53–250 μm) fractions. Soil particle-size fractions with higher bioavailability (i.e., coarse and fine sands) showed greater influence on PAE congener bioconcentration factors compared to PAE molecular structures for both maize and wheat tissues. More PAEs were allocated to maize and wheat grains with increased soil PAE storages from wastewater irrigation. Additional findings showed that levels of both non-cancer and carcinogenic risk for PAE congeners in wheat were higher than those in maize, suggesting that wheat food security should be prioritized. In conclusion, increased soil PAE concentrations specifically in maize and wheat grains indicate that wastewater irrigation can pose a contamination threat to food resources.

Highlights

Soil is a microcosm in which various factors, such as soil organic matter (SOM), clay minerals and biogeochemical process, may significantly impact the dynamics of hydrophobic organic pollutants in soils[27]
The PAE concentrations in the soil from the area irrigated by wastewater were significantly higher than those in the reference adjacent agricultural soil irrigated by groundwater (Supplementary Table S4)
This study reports on new findings related to the occurrence, bioavailability and health risks of PAEs in a soil-cereal crop system

Summary

Introduction

Microorganisms of soils and intrinsic physicochemical properties of pollutants[8,17,18,19,20,21] Most of these studies were conducted in vegetable crop fields, whereas the dynamics of PAEs in soil–cereal crop systems, the cereal cropping system from actual agricultural fields, remains unclear. Soil is a microcosm in which various factors, such as soil organic matter (SOM), clay minerals and biogeochemical process, may significantly impact the dynamics of hydrophobic organic pollutants in soils[27]. There is little information on assessing the biouptake of PAEs in a maize-wheat double-cropping system irrigated by wastewater based on the partition of PAEs in different soil particle-size fractions. The correlation between distribution patterns of PAEs in soil and accumulation of PAEs in maize and wheat were investigated, and the bioavailability and environmental risks of PAEs were evaluated

Methods

Results

Conclusion