添加剂对伴矿景天修复石灰性铅冶炼污染土壤的影响

为了探讨利用伴矿景天(Sedum plumbizincicola)修复北方重金属污染土壤的可行性,在河南省某铅冶炼形成的污染农田(全镉、铅和锌含量分别为2.65、261和130 mg·kg-1)上种植种子苗或扦插苗伴矿景天,并设对照(CK)、单独尿素(U)、尿素和单质硫(U+S)、尿素与鸡粪(U+CM)配合处理,生长7个月后采样分析.结果表明,种子苗产量比扦插苗高45.8%~162.0%,U、U+CM处理产量均明显高于CK,而U+S处理产量有所下降.种子苗地上部镉含量比扦插苗高15%~99%(p0.05),多数处理铅和锌含量也是种子苗高于扦插苗.与CK相比,各处理措施均导致伴矿景天地上部镉和铅含量下降,而U+S、U+CM处理均导致伴矿景天地上部锌含量上升.从伴矿景天地上部重金属积累量判断,与CK相比,对于镉,仅种子苗U+CM处理镉积累量有所上升;U处理种子苗和扦插苗地上部锌积累量分别比CK上升43.5%和32.3%,两种苗U+S处理锌积累量比CK分别上升11.1%和22.3%.种子苗和扦插苗地上部镉的积累量分别为137~178 g·hm-2和43.7~64.8 g·hm-2,锌的积累量分别为297~1042 g·hm-2和162~326 g·hm-2,两类苗对铅的积累量小于28.8 g·hm-2.U+CM处理对伴矿景天地上部锌吸收的促进作用主要是由于鸡粪中含有大量的有效锌.以上结果表明,可利用种子苗伴矿景天结合尿素的施用对铅冶炼污染石灰性土壤进行修复.

Influence of amendments on Sedum plumbizincicola phytoextraction of metals from a lead-smelting polluted calcareous soil

This study investigates the feasibility of phytoextraction in a heavy metal contaminated soil in Henan Province in northern China with Sedum plumbizincicola, a Cd/Zn hyperaccumulator originally growing in southern China. Sedum plumbizincicola seedlings or stem cuttings were transplanted to a lead-smelting contaminated field soil with total concentration of Cd, Pb and Zn of 2.65, 261 and 130 mg · kg^-1, respectively. The soil was amended with urea (U), urea and elementary sulfur (U+S), and urea and chicken manure (U+CM), together with an un-amended control (CK). The plants were harvested after seven months to evaluate metal accumulation. The biomass yields of seedlings were 45.8% to 162.0% higher than the stem cuttings. U and U+CM resulted in higher biomass yield than the control, while that of U+S was lower than the control. Shoot Cd concentration of seedlings were 15%~99% higher than the stem cuttings (p<0.05), and the concentrations of Pb and Zn in the shoots of seedlings were also higher than those of the stem cuttings. Shoot concentrations of Pb of the plants grown in the amended soils were lower than the control, while Zn concentrations of plants grown in U+S and U+CM amended soil were higher than the control. Plants grown in the U+S treatment had higher Cd shoot accumulation than the control, while the other treatments resulted in lower Cd uptake than the control. Zn accumulation in seedlings and stem cuttings for the U+CM treatment were 43.5% and 32.3% higher than the control, respectively. Shoot accumulation of Cd in the seedlings and stem cuttings ranged 137~178 g · hm^-2 and 43.7~64.8 g · hm^-2, respectively, while Zn accumulation ranged 297~1042 g · hm^-2 and 162~326 g · hm^-2, respectively. Pb accumulation was less than 28.8 g · hm^-2. The amendment of U+CM resulted in the highest Zn accumulation and was attributed to the high concentration of Zn in the chicken manure.The results suggest that N and S amended heavy metal(particularly Cd and Zn) contaminated calcareous soils can be phytoremediated with seedlings of Sedum plumbizincicola.