不同改良剂对汞矿区水稻汞污染的钝化效果初探

Preliminary study on passivation effects of mercury in rice by different amendments in mercury-mining areas

采用原位盆栽的方法,初步探究了施用不同改良剂对汞矿区水稻总汞含量的钝化效果,结果表明：汞矿区土壤总汞含量超出GB 15618-2008的限量值50倍以上,大米总汞含量也超出GB 2762-2005的限量值10倍多;改良剂在一定程度上能抑制水稻对汞的富集,在梅子溪（MZX）和敖寨（AZ）,大米总汞降低率分别为10.86%~40.95%和13.54%~35.80%,降低量分别为23.00~90.50 ng/g和34.54~68.78 ng/g;农家肥处理组在两地获得了最高的平均降低率和降低量分别为30.55%和70.94 ng/g,其次为粉煤灰、约30.18%和70.59 ng/g,海泡石对大米汞的钝化效果最低、约为11.98%和28.77 ng/g;灌溉方式和施肥种类等农艺措施的改变会对水稻的富集能力产生重要影响,改良剂配施产生了积极作用,凹凸棒土＋钙镁磷肥配施对水稻总汞的降低量较单施分别提高了约12.31 ng/g和19.67 ng/g;粘土矿物的不同所产生的钝化效果存在一定差异,表现为麦饭石粉〉凹凸棒土〉活性白土〉海泡石。

Situ pot method was used to study the passivation effects of different amendments on total mercury in rice in mercury-mining areas. The results showed that the total mercury in soil and rice exceeded about more than 50 times （the limited value in GB 15618-2008）and 10 times （the limited value in GB 2762-2005）, respectively. Amendments could generally inhibit the accumulation of total mercury in rice from soil in Meizixi （MZX） and Aozhai （AZ）, and the reducing rates reached 10.86%-40.95% and 13.54%-35.8% with a reduction of 23.0 ng/g-90.5 ng/g and 34.54 ng/g-68.78 ng/g. The farmyard manure treatment had the highest average reduetive rate and amounts with 30.55% and 70.94 ng/g in the two places, and followed by fly ash with 30.18% and 70.59 ng/g. The passivation effect of Epiolite was the lowest among all amendments, the reduction rate and amount were 11.98% and 28.77 ng/g. The variance of agronomic measures including irrigation and fertilization had important impact on the accumulation ability of rice to mercury. Compared with the single application,the combination of Attapulgite clay and Calcium magnesium phosphate （fertilizer） respectively improve the reduction amounts about 12.31 ng/g and 19.67 ng/g. Therefore, the combination of different amendments owned a certain prospect. The various clay minerals produced different effects with Medical stone powder〉Attapulgite clay〉Activated clay〉Sepiolite.