污水灌溉后土壤重金属汞和砷积累变化规律及对番茄的影响

污水灌溉对土壤、作物的影响日益受到人们的关注。通过日光温室内的污水滴灌试验,分析了污水灌溉后重金属Hg、As在土壤中的集聚分布规律和污水灌溉对番茄生长、产量与品质的影响,同时探讨了在番茄果实中的残留状况。结果表明,污水灌溉后重金属Hg、As在不同土层集聚差异较大,Hg、As在根区10~30 cm土层出现了富集现象,且二者具有很好的相关性,说明土壤受灌溉外源污染影响较大;污水灌溉对番茄的果实产量和品质有一定的影响,与清水处理相比番茄的产量减少7.68%,果实中的可溶性固形物提高了46.2%、VC含量增加76.76%,酸度和可溶性总糖含量基本持平,蛋白质降低了55.84%;番茄果实检测表明,与清水处理相比,Hg的残留量增加了28%,As增加了112%,但含量均未超标。

EFFECTS OF SEWAGE IRRIGATION ON TOMATO GROWTH AND ACCUMULATION OF Hg AND As IN SOIL

Sewage irrigation has been paid more attention due to its adverse effects on soil and crops.An experiment was carried out in a greenhouse equipped with a drip irrigation system to investigate the distribution patterns of heavy metals (Hg and As) and tomato development,yield and fruit quality under sewage irrigation.Results showed that significant spatial variation of heavy metal contents was observed in soil profiles.Hg and As were enriched in the 10~30 cm layer,showing close correlation between them,which indicated that the soil environment was seriously affected by external pollutants.Generally,sewage irrigation influenced growth of tomato fruits and its quality,as shown by a lower growth rate,7 68% lower yield,46.2% higher soluble solid content,76.76% higher Vccontent,55.84% lower protein content and similar contents of the acidity and total soluble sugar than with freshwater irrigation.Sewage irrigation also increased Hg content by 28% and As by 112%,but not above the food safety criteria.