Document Detail

Copper uptake and elimination in Daphnia magna determined by the 67Cu radiotracer.
MedLine Citation:
PMID:  19530890     Owner:  NLM     Status:  Publisher    
Among the many toxic metals, the biokinetics of copper (Cu) in the freshwater cladoceran Daphnia magna has not been studied due to the lack of an ideal radiotracer. In this study, we used a gamma radiotracer, 67Cu (half life=61.9 h), to study the uptake of copper from the dissolved phase and its assimilation and efflux in D. magna, an important toxicity testing species. The influx rate of Cu from the dissolved phase increased with dissolved Cu concentration, with a calculated uptake rate constant of 0.055 L/g/h. The assimilation efficiency (AE) of Cu decreased significantly (from 92% to 16%) as in the available food concentration increased, and the AE differed among the food types. As low as 1% of Cu AE was found in daphnids fed high concentrations (1.54 mg /L) of the green algae Chlorella pyrenoidosa. The AE decreased linearly as the ingestion rate of the daphnids increased. The efflux rate constant was 0.20/d at high food concentrations. Excretion accounted for 82-94% of total Cu loss from the animals, although Cu was also maternally transferred from female adults to their offspring. Under conditions of high food concentrations, about 6.5% of the mother's Cu was transferred to the offsprings over 7 days. We concluded that Cu accumulation is dominated by uptake from dietary sources, and there is a substantial need to understand the dietary toxicity of Cu to daphnids. Our study has implications for the choice of food particles in conducting the Cu toxicity testing in cladocerans.
Chun-Mei Zhao; Wenhong Fan; Wen-Xiong Wang
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2009-6-16
Journal Detail:
Title:  Environmental toxicology and chemistry / SETAC     Volume:  -     ISSN:  0730-7268     ISO Abbreviation:  Environ. Toxicol. Chem.     Publication Date:  2009 Jun 
Date Detail:
Created Date:  2009-6-17     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8308958     Medline TA:  Environ Toxicol Chem     Country:  -    
Other Details:
Languages:  ENG     Pagination:  1     Citation Subset:  -    
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