猪粪中铜对东北黑土的污染风险评价

集约化养殖使用大量铜(Cu)作为饲料添加剂，养殖废物的排放和利用可导致一定的环境问题.本文以东北黑土为供试材料，通过在盆栽试验中添加不同Cu浓度的猪粪来模拟不同施肥年限的菜园土，研究土壤中Cu累积对小白菜地上部分Cu浓度、地上部分生物量、土壤微生物生物量碳和土壤酶(脱氢酶、脲酶、酸性磷酸酶)活性的影响.结果表明：单独施用猪粪显著增加了小白菜地上部分生物量，对其Cu浓度则没有显著影响.猪粪的施用在一定时期内显著促进了脱氢酶和脲酶的活性，但随土壤Cu浓度的增加，脱氢酶、脲酶、酸性磷酸酶活性逐渐受到抑制.当土壤全Cu浓度达到301.3 mg·kg^-1后，小白菜地上部分生物量、土壤微生物生物量碳及脱氢酶、脲酶、酸性磷酸酶活性均受到强烈抑制.小白菜地上部分Cu浓度与土壤全Cu和水溶态Cu浓度呈显著正相关(P<0.01)，而地上部分生物量与土壤全Cu浓度呈显著负相关(P<0.05).研究表明，可用于种植蔬菜的黑土Cu浓度阈值应小于301.3 mg·kg^-1.

Risk assessment of pig manure Cu-contamination of black soil in Northeast China.

Copper (Cu) is massively used as feed additives in intensive farms, and the discharge and utilization of livestock wastes may cause certain environmental problems. In this paper, a cultivated black soil in Northeast China was sampled, and added with pig manures that contained different concentration of Cu to simulate the vegetable soil under different years of pig manure fertilization. With this soil, a pot experiment was conducted to study the effects of soil Cu accumulation via the application of the pig manures on the aboveground biomass and its Cu concentration of pakchoi (Brassica chinensis L.), soil microbial biomass carbon, and soil enzymes (dehydrogenase, urease, and acid phosphatase) activities. The results showed that pig manure application increased the aboveground biomass of pakchoi significantly, but had no significant effects on the aboveground biomass Cu concentration. Under the application of pig manure, soil dehydrogenase and urease activities increased in a definite period of time, but their activities as well as soil acid phosphatase activity were depressed gradually with the increase of soil Cu concentration. When the soil total Cu concentration reached 301.3 mg·kg^-1, the aboveground biomass of pakchoi, soil microbial biomass carbon, and the activities of dehydrogenase, urease, and acid phosphatase were greatly reducd. The aboveground biomass Cu concentration of pakchoi had significant positive correlations with the concentration of soil total and water soluble Cu (P<0.01), while the aboveground biomass was negatively correlated with soil total Cu concentration (P<0.05). It was suggested that the threshold value of Cu in black soil under vegetable cultivation should be less than 301.3 mg·kg^-1.