Ecotoxicity of cadmium in a soil collembolan-predatory mite food chain: Can we use the15N labeled litter addition method to assess soil functional change?
Effects of cadmium (Cd) on predator-prey relationships and soil ecological function are poorly understood and there are few methods available to measure soil functional change. Thus, we structured a soil-dwelling food chain containing the predatory mite Hypoaspis aculeifer and its collembolan prey Folsomia candida to study the effects of Cd exposure for eight weeks in a spiked soil aged for five years. The15N labeled litter was added as food to analyze the change in nitrogen (N) transfer content. H. aculeifer reproduction and growth and the survival and reproduction of F. candida were all negatively affected by Cd exposure, and H. aculeifer reproduction was the most sensitive parameter. The sensitivity responses of F. candida and H. aculeifer were different from those using the previous single species test. The results suggest that predator-prey interactions might influence the toxicity of Cd by predation and food restriction. Cadmium lethal body concentrations of adults and juveniles of F. candida and H. aculeifer juveniles were 500-600, 180-270 and 8-10 μg g-1, respectively. The content of N transfer from litter to animals in the food chain decreased significantly with increasing soil Cd concentration between 100 and 400 mg kg-1. The results suggest that the15N labeled litter addition method is potentially useful for quantitative assessment of soil functional change for further risk assessment purposes.
Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of the Chinese Academy of Sciences, Beijing 100049, China.
Dong
D
Zhu
Institute of Plant Physiology and Ecology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China. Electronic address: xinke@sibs.ac.cn.
Xin
X
Ke
Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China. Electronic address: lhwu@issas.ac.cn.
Longhua
L
Wu
Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
Zhu
Z
Li
Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
Peter
P
Christie
Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China.
Yongming
Y
Luo
D000818:Animals; D002104:Cadmium / Q000633:toxicity*; D002681:China; D004784:Environmental Monitoring; D020387:Food Chain; D007928:Lethal Dose 50; D008925:Mites / Q000187:drug effects* / Q000254:growth & development / Q000469:parasitology*; D011235:Predatory Behavior / Q000187:drug effects*; D012098:Reproduction / Q000187:drug effects*; D018570:Risk Assessment; D012987:Soil / Q000737:chemistry* / Q000469:parasitology; D012989:Soil Pollutants / Q000633:toxicity*; D018675:Toxicity Tests
D012987:Soil; D012989:Soil Pollutants; D002104:Cadmium
Heavy metal accumulation; Nitrogen transfer content; Predator-prey interactions; Soil microarthropods