高铜、高锌猪粪对蚯蚓的急性毒性效应研究

Acute toxicological effects of excessive Cu and Zn-containing in pig manure on earthworm

测定了高Cu、高Zn猪粪条件下Cu、Zn单一与复合污染对蚯蚓的急性致死及亚致死效应.结果表明,Cu、Zn浓度与蚯蚓死亡率显著正相关(a=0.05,rCu=0.99,rZn=0.99),与体重增长率显著负相关(a=0.05,rCu=-0.99,rZn=-0.96).蚯蚓个体对Cu、Zn的耐受程度不同,其毒性阈值(引起蚯蚓个体死亡浓度)分别为:Cu250mg.kg-1、Zn400mg.kg-1.LD50分别为:Cu646.68mg.kg-1、Zn947.38mg.kg-1.复合污染情况下,Cu浓度为2505、00mg.kg-1时,Cu、Zn复合污染表现为协同效应;Cu浓度为750mg.kg-1时,Cu、Zn复合污染表现为拮抗效应.可见,猪粪中Cu、Zn复合污染的毒性效应与各组浓度组合密切相关.

Cu and Zn are popularly used as additives in animal feed in China, which could result in their excessive accumulation in manure to a toxic level, and thus, possibly threaten the environment when the manure is applied to farmland. In this paper, the acute and sub-acute lethal effects of pig manure with excessive Cu and Zn on earthworm were studied, and the results indicated that the concentration of Cu and Zn in pig manure had a significantly positive correlation with the mortality of earthworm, while a significantly negative correlation with earthworm growth rate. The individuals of earthworm had different tolerance to excessive Cu and Zn, with the threshold values causing death being 250 mg· kg^-1 and 400 mg· kg^- lfor Cu and Zn, respectively. The LD50 was 646.68 mg·kg^-1 for Cu, and 947.38 mg·kg^-1 for Zn. A strong synergistic effect was observed under the combined pollution of 250 mg·kg^- 1 for Cu and 500 mg· kg^- 1 for Zn, whereas antagonistic effect happened when 750 mg· kg^- 1 for Cu was supplied, suggesting that the joint toxic effects of Cu and Zn on earthworm were closely correlated to their concentrations in pig manure.