重庆市沿江流域土壤中有机氯农药的垂直分布特征

通过检测重庆市长江沿岸表层土壤(0-5 cm)和深层土壤(0-20 cm)中六六六和滴滴涕的含量发现,表层土壤中总六六六(包括α-六六六、β-六六六、γ-六六六、δ-六六六)和总滴滴涕(包括p,p'-DDE、p,p'-DDD、o,p'-DDT、p,p'-DDT)含量范围为0.185-1.374 ng/g和0.807-38.281 ng/g,分别对应深层的总六六六含量0.079 5-1.692 ng/g和总滴滴涕含量0.308-88.306 ng/g.研究区内有机氯农药在土壤中的垂直分布反应了滴滴涕残留是"老"的来源,并证实了林丹的使用对该区域的有机氯农药污染有一定的影响.

Abstract：

Concentrations of hexachlorocyclohexane(HCH)and dichlorodiphenyltrichloroethane(DDT)were determined in shallow subsurface(0～5 cm depth)and deep soil layers(5～20 cm depth)from the agricultural soils along the Yangtze River in Chongqing,China.Concentrations of total HCHs(including α-HCH,β-HCH,γ-HCH and δ-HCH)and total DDTs(including p,p'-DDE,p,p'-DDD,o,p'-DDT and p,p'-DDT)in shallow subsurface soils ranged from 0.185 to 1.374 ng/g,averaging 0.479 ng/g,and from 0.807 ng/g to 38.281 ng/g,averaging 7.274 ng/g,respectively,and those in the deeper layers ranged from 0.079 5 to 1.692 ng/g,averaging 0.564 ng/g,and from 0.308 to 88.306 ng/g,averaging 13.718 ng/g,respectively.The vertical distribution of HCHs and DDTs suggested that DDT residues resulted from"old"sources and that the contamination of HCHs in this region was partially attributed to the local use of lindane.     

重庆都市经济圈土壤Cd元素含量分布特征与评价

通过重庆都市经济圈网格化深浅层土壤及评价样品的调查分析,阐述重金属Cd区域上的分布现状,并绘制土壤Cd元素环境质量分级图.研究区浅层土壤Cd背景平均值0.27μg/g,深层0.13μg/g.根据《土壤环境质量标准》对区内土壤进行统计分类,区内浅层土壤Cd元素Ⅱ类土及以上土类面积为83.97%.土壤Cd高含量值主要分布在金刀峡镇北、含谷—白市驿、木耳—王家和玉峰山镇等区域.含谷—白市驿、木耳—王家、西彭北等区域的高Cd含量受人类活动影响比较明显,其中含谷—白市驿区Cd主要来源于生活垃圾、排污底泥和降尘,而金刀峡镇北的高Cd含量属自然背景变化的范畴.