and Neutral Red assay, ethanolic extracts for L-YES, native fresh sediments for the fish embryo test, and pore water for the immobilization test with D. magna.
Institut für Umweltwissenschaften, Universität Koblenz-Landau, Campus Landau
Ecotoxicological effects of contaminated sediments on fish: Are current risk assessment protocols sufficient? M. Schulze - Sylvester¹ ², W. Heimann¹, M. Brinkmann², S. Maletz², T. - B. Seiler², H. Zielke², R. Schulz¹, H. Hollert²
¹ Institute for Environmental Science, University of Landau, Germany ² Department of Ecosystem Analysis, Institute for Environmental Research, RWTH Aachen University, Germany
Results
• While the water quality of the Rhine River has improved substantially, contaminated sediments remain an important exposure pathway for aquatic fauna
• We found dioxin-like, estrogenic, teratogenic, embryotoxic, and cytotoxic effects in all samples, but no D. magna acute toxicity
• We tested sediments of an oxbow lake of the Rhine River using 5 bioassays: (1) acute cytotoxicity test (cytotoxic effects), (2) EROD assay (dioxin-like effects), (3) L-YES (estrogenic effects), (4) fish embryo toxicity test with Danio rerio (teratogenic and embryotoxic effects), and (5) immobilization test with Daphnia magna neonates (acute toxicity)
NR 50 [mg SEQ ml Medium-1]
Abstract 60
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• Results of the fish embryo and the Neutral Red assay indicate increasing effects with increasing distance to the main river affluent
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• No distance effect was found for the EROD or the L-YES 60 120 180 240 300 360 420 480 540 600
Distance from affluent [m] Linear regression showing 95 % CI of NR50 values from sediment extracts as a function of distance from the river affluent. Toxicity increases with distance.
• The official German risk assessment for dredged freshwater sediments (HABAB-WSV) includes the test with D. magna besides tests with algae and bacteria • Our results suggest that sediments can have ecotoxicologically relevant effects on fish which are not addressed sufficiently by current regulatory risk assessment
EEQ values from L-YES and TEQ values from the EROD assay. For some samples an EEQ could not be determined (ND) Location and depth of the Karlskopf oxbow lake and locations of sampling stations (Heimann et al. 2011)
Distance from EEQ TEQ affluent [m] [ng Estradiol g [ng Dioxin g SEQ-1] SEQ-1] 60 120 180 240 300 360 420 480 540 600 Control
ND ND 1.77 1.17 ND 2.03 1.42 ND 1.55 1.89 ND
5.87 4.89 4.53 4.97 5.29 5.15 7.92 5.75 7.12 3.62 ND
A normally pigmented (A) and an unpigmented embryo of D. rerio after 48 h exposure to our sediment samples (B) A
B
Absence of pigmentation, blood circuit, and rate of mortality in D. rerio embryos after 48 h exposition to fresh native sediments. Effects increase with distance from the river affluent.
Methods • Ten surface sediment samples (3 for D. magna tests) taken in the Karlskopf oxbow lake at increasing distances from the river affluent and a process control were tested
• The results from the Neutral red, L-YES, and the EROD assay were expressed as NR50 (neutral red retention of 50%), EEQs (Estradiol equivalents), and TEQs (Toxic equivalents), respectivly
• We used acetonic extracts and RTL-W1 cells for the EROD and Neutral Red assay, ethanolic extracts for L-YES, native fresh sediments for the fish embryo test, and pore water for the immobilization test with D. magna
• We counted mortality for the fish embryo test • The absence of pigmentation and blood circulation after 48 h were used as indicators of development retardations
