Nickel Accumulation And Toxicity To Earthworm Eisenia Fetida In A Range Of Chinese Soils

Nickel accumulation and toxicity to earthworm Eisenia fetida in thirteen Chinese soils were investigated following ISO guidelines. The main objectives were to study the difference of the acute toxicity of nickel to E. fetida in 5 typical Chinese soils; to investigate the sublethal effects of nickel on earthworm growth, cocoon output and juvenile production in 13 Chinese soil; and to investigate the bioaccumulation of nickel in earthworm E. fetida in a range of Chinese soils.The results of acute toxicity test showed that nickel toxicity to E. fetida differed in different soils, and 50% lethal concentrations (14 LC50) varied from 684.0 to 1970.6mg/kg. Based on LC50 values, nickel toxicity to E. fetida in 5 test soils could be ranked as red earth (Jinxian, Jiangxi)>fluvo-aquic soil (Yucheng, Shandong)> fluvo-aquic soil (Luancheng, Hebei)> paddy soil (Changshu, Jiangsu)> black soil (Hailun, Heilongjiang).The results of sublethal toxicity test showed that earthworm body weight development was not sensitive to nickel. In most cases, siginificant inhibition of growth was only observed at high concentrations such as 560 and 1000 mg Ni/kg. Relatively, reproduction of E.fetida was a rather sensitive pesponse to nickel. Lower concentrations of nickel enhanced the production of cocoons and juveniles in some soils, indicating a hormesis effect. The ECx values for the inhibition of cocoon and juvenile production varied greatly among the 13 soils. The EC10, EC2o and EC50 for cocoon production varied from 45.2 to 405.5 mg/kg, 72.8 to 473.2 mg/kg, and 153.1 to 620.9 mg/kg, respectively. The EC10, EC20 and EC50 for juvenile production varied from 40.6 to 204.2 mg/kg,56.2 to 233.3 mg/kg, and 106.7 to 381.1 mg/kg, respectively. No significant correlation between soil properties and ECx was present. More Chinese soils, therefore, were suggested to be involved in future study to elucidate the relationship between soil properties and nickel toxicities to earthworm production.The results of the bioaccumulation test indicated that there was a significant positive relationship between the soil nickel concentrations and the tissue nickel concentrations in earthworm. It was suggested that the accumulation of nickel in earthworm tissues could be used as a biological indicator for nickel contaminattion of soil.The ecotoxicity data generated in the present study might lend help in the development of t-BLM for predicting the effects of nickel on earthworm reproduction in a range of Chinese soils, and could be useful for the development of risk-based soil environmental quality standards in china.