Reproductive toxicity of dietary zinc to Daphnia magna
De Schamphelaere, K.A.C.; Canli, M.; Van Lierde, V.; Forrez, I.; Vanhaecke, F.; Janssen, C.R. (2004). Reproductive toxicity of dietary zinc to Daphnia magna. Aquat. Toxicol. 70(3): 233-244. dx.doi.org/10.1016/j.aquatox.2004.09.008 In: Aquatic Toxicology. Elsevier Science: Tokyo; New York; London; Amsterdam. ISSN 0166-445X; e-ISSN 1879-1514, more |  |
| Keywords | Chemical elements > Metals > Heavy metals
Chemical elements > Metals > Heavy metals > Zinc
Environments > Aquatic environment
Ligands
Models
Properties > Biological properties > Toxicity
Toxicology > Ecotoxicology
Trophic levels
Water > Fresh water
Arthropoda [WoRMS]; Branchiopoda [WoRMS]; Diplostraca [WoRMS]; Crustacea [WoRMS]; Daphnia magna Straus, 1820 [WoRMS]; Invertebrata
Fresh water | | Author keywords | Daphnia magna; dietborne exposure; zinc; biotic ligand model |
| Authors | | Top | - De Schamphelaere, K.A.C., more
- Canli, M.
- Van Lierde, V.
| - Forrez, I.
- Vanhaecke, F., more
- Janssen, C.R., more
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| Abstract | Regulatory assessments of metals in freshwaters are mostly based on dissolved metal concentrations, assuming that toxicity is caused by waterborne metal only. Little attention has been directed to the toxicity of dietary metals to freshwater invertebrates. In this study the chronic toxicity of dietary zinc to Daphnia magna was investigated. The green alga Pseudokirchneriella subcapitata was exposed for 64 h to a control and three dissolved zinc concentrations, i.e. 23, 28 and 61 µg L-1, resulting in internal zinc burdens in the algae of 130, 200, 320 and 490 µg g-1 dry weight, respectively. These algae were used as a food source in chronic, 21-day bioassays with D. magna in a test medium to which no dissolved zinc was added. None of the treatments resulted in effects on feeding rates or somatic growth of D. magna. In contrast, a significant 40% decrease of total reproduction (number of juveniles per adult) was observed in the 28 and 61 µg L-1 treatments. Time to first brood was not affected, whereas the mean brood size and the fraction of reproducing parent daphnids were reduced from the second brood onwards and the magnitude of these reductions increased with each subsequent brood. The reduced reproduction was accompanied with an elevated zinc accumulation in the 61 µg L-1 treatment only, suggesting that total body burden is no good indicator of dietary zinc toxicity. Overall our data suggest that dietary zinc specifically targets reproduction in D. magna through accumulation in particular target sites, possibly cells or tissues where vitellogenin synthesis or processing occur. Further, our data illustrate that the potential importance of the dietary exposure route should be carefully considered and interpreted in regulatory assessments of zinc. |
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