苏南某市农田土壤有毒有害元素分布状况及影响因素

本研究选择工业化与城市化水平较高,且工农业经济发展水平相对较平衡,具有蔬菜种植较长历史的苏南某市为试点区,重点探讨农田土壤重金属污染状况与分布规律,以及土壤利用方式、轮作方式、作物品种及种植年限对土壤重金属污染状况及分布规律的影响。研究结果表明供试区土壤中各种重金属含量离散较大,Hg、As、Pb、Cr、Cd、Cu含量范围分别为0.05~2.35、4.28~42.90、22.50~106.50、49.80~101.70、0.09~2.16和15.00~125.40mg/kg。试区土壤有毒有害元素Cd、Pb、Cu及Zn比杭州近郊土壤中的含量低,Ni含量较高;除Cu外,试区土壤有毒有害元素含量(均值)As、Cd、Pb和Zn含量均低于香港菜园土;轮作方式和不同作物的种植对土壤中部分有毒有害元素的积累有一定的影响,但影响并不突出;蔬菜种植年限对土壤中有毒有害元素的积累有明显的影响作用,轻度熟化菜园土中有毒有害元素的含量明显高于中等熟化菜园土。

DISTRIBUTION OF HARMFUL CHEMICAL ELEMENTS IN AGRICULTURAL SOIL OF SOUTH JIANGSU, CHINA

The focus of this research is to discuss distribution of some harmful chemical elements in farmland, as affected by soil utilization, crop rotation, variety of crops or vegetation and duration of cultivation. Results show that contents of harmful chemical elements vary greatly in the test fields from 0.05 to 2.35 for Hg, 4.28 to 42.90 for As, 22.50 to 106.50 for Pb, 49.80 to 101.70 for Cr, 0.09 to2.16 for Cd and 15.00 to 125.40 mg/kg for Cu. The contents of Cd, Pb, Cu and Zn in the test fields are lower than in that, respectively, in the vegetable soil in Hangzhou, but the content of Ni is the opposite. Compared with those in vegetable soil in Hong Kong, the average contents of As, Cd, Pb and Zn are lower, but Cu is an exception. Crop rotation and crop diversity has a definite but insignificant influence on accumulation of some toxic heavy metals in soil, whereas duration of cultivation has a much obvious one. Contents of harmful chemical elements in vegetable soils low in mellowness are obviously higher than in those moderate in mellowness.