多溴联苯醚在河套农灌区土壤和水体中的分布特征

Distribution of PBDEs in Soil and Water from Hetao Agriculture Irrigation Area

PBDEs作为一类全球性的新兴持久性有机污染物,因其具有疏水性,土壤和沉积物对其有很强的固着能力,被认为很难进入地下水中。文章在河套平原典型的黄河农灌区采集地下水、地表水以及表层土壤样品,利用GC-μECD和GC-MS方法测定发现,地下水和地表水中均检测到PBDEs,且主要为BDE209,其在地下水中含量高达5.3μg/L,而地表水中仅为0.03μg/L,揭示PBDEs存在污染地下水的可能性。对土壤中PBDEs的分析发现,其优势同系物为BDE47、100、183和99,主要富集在地面以下0~5 cm和10~15 cm处,该范围普遍发现农用地膜(PBDEs≤5μg/g)的残留物。此外,研究区主要农作物(玉米、番茄、瓜类、小麦和葵花)中,广泛利用地膜的玉米种植土壤中PBDEs的含量最高,达77.13 ng/g。研究显示,降雨淋滤以及灌溉水入渗作用下,地膜中PBDEs的释放可能是研究区土壤以及地下水中PBDEs不可忽略的重要污染源。

Polybrominated diphenyl ethers （PBDES）, an emerging kind of global POPs, has been recognized to be hard to get into groundwater because it is a hydrophobic material that can be strongly adsorbed on soil and sediment. Groundwater, surface water and soil were collected from typical Yellow River water irrigation area located in Hetao Plain, contents of PBDEs were determined by GC-IxECD and GC-MS. Results showed that PBDEs was detected in both groundwater and surface water, with major homolog as BDE209, which was as high as 5.3 p^g/L in groundwater while only 0.03 p.g/L in surface water, which indicated that there is a way for PBDEs into groundwater. Analysis of PBDEs in soil showed that major homologs were BDE47, 100, 183 and 99, which were mainly enriched in the depth of 0-5 cm and 10~15 cm where the residence of agricultural plastic film （PBDEs≤ 5 μg/g） was commonly found. Concentration of PBDEs in soil, growing corn and widely used with plastic film, was the highest 77.13 ng/g of that in soil growing corn, tomato, melons, wheat and sunflower in the study area, which indicated that PBDEs released from plastic film under rainfall leaching and irrigation water infiltration should be a non-ignorable and important source for PBDEs pollution in soil and groundwater.