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- Title
A scaled-up system to evaluate zooplankton spatial avoidance and the population immediate decline concentration.
- Authors
Rosa, Rita; Materatski, Patrick; Moreira-Santos, Matilde; Sousa, José Paulo; Ribeiro, Rui
- Abstract
Most laboratory tests may underestimate adverse effects in real scenarios of contamination because they imply the forced exposure of organisms to contaminants, thus overlooking the possibility of emigration. Avoidance from contaminants has been observed in several aquatic organisms, and avoidance-based tests have been recommended to be included in risk assessment studies. To reduce uncertainty in the extrapolation of laboratory derived results, the first aim of the present study was to compare both the median avoidance concentration and the lowest-observed-effect gradient (LOEG) values of atrazine for the cladoceran Daphnia magna, between an already developed 1.1-m-long system and a scaled-up system, three times longer. Second, the present study aimed at evaluating the population immediate decline-the proportion of the population that disappears (avoids and, if not, dies)-through the integration of the relationships between lethality and avoidance versus contaminant concentration. Daphnia magna significantly avoided atrazine, during 12-h exposures, with similar results in the original and scaled-up systems. The population immediate decline at the 48-h median lethal concentration would be 94%. Even at a concentration eliciting only 5% mortality, the population immediate decline would be over 50%. Achieving a higher pertinence of avoidance results and a better understanding of the LOEG values and their time dependence, scaling up the system further both spatially and temporally, and modeling explicit spatial dynamics in exposure and organism movement in space and time are needed. Environ. Toxicol. Chem. 2012;31:1301-1305. © 2012 SETAC
- Subjects
PHYSIOLOGICAL effects of pollution; ENVIRONMENTAL risk assessment; DAPHNIA magna; ATRAZINE; ZOOPLANKTON; ENVIRONMENTAL toxicology
- Publication
Environmental Toxicology & Chemistry, 2012, Vol 31, Issue 6, p1301
- ISSN
0730-7268
- Publication type
Article
- DOI
10.1002/etc.1813