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Chencho Norbu Prof. Timothy J. Downs Edward Yeboah Dr. L.J.R. Scholtens Dr. Jyotsna Bapat Maren Oelbermann Ph.D. Sayyed Ahang Kowsar Jaime Alexandra Webbe Bram Govaerts Ph.D. Nele Verhulst M. Sc. Goodspeed Kopolo Maria Rosário Partidário Mr. N’guessan Alphonse Kouassi John All Ph.D. JD Narcisa Pricope Leslie Lipper 《Natural resources forum》2008,32(3):252-256
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Sensitivity of submersed freshwater macrophytes and endpoints in laboratory toxicity tests 总被引:1,自引:0,他引:1
Arts GH Belgers JD Hoekzema CH Thissen JT 《Environmental pollution (Barking, Essex : 1987)》2008,156(1):199-206
The toxicological sensitivity and variability of a range of macrophyte endpoints were statistically tested with data from chronic, non-axenic, macrophyte toxicity tests. Five submersed freshwater macrophytes, four pesticides/biocides and 13 endpoints were included in the statistical analyses. Root endpoints, reflecting root growth, were most sensitive in the toxicity tests, while endpoints relating to biomass, growth and shoot length were less sensitive. The endpoints with the lowest coefficients of variation were not necessarily the endpoints, which were toxicologically most sensitive. Differences in sensitivity were in the range of 10-1000 for different macrophyte-specific endpoints. No macrophyte species was consistently the most sensitive. Criteria to select endpoints in macrophyte toxicity tests should include toxicological sensitivity, variance and ecological relevance. Hence, macrophyte toxicity tests should comprise an array of endpoints, including very sensitive endpoints like those relating to root growth. 相似文献
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We tested the effects of the herbicide metsulfuron-methyl on growth of the submerged macrophyte Myriophyllum spicatum under laboratory conditions using different exposure scenarios. The exposures of each scenario were comparable in the concentration × time factor, viz., the same 21-d time-weighted average (TWA) concentrations but variable in peak exposure concentrations (ranging from 0.1 to 21 000 ng ai L−1) and exposure periods (1, 3, 7, 14 or 21 d). To study recovery potential of the exposed M. spicatum plants we continued the observation on shoot and root growth for another 21 d in herbicide-free medium so that the total observation period was 42 d. Non-destructive endpoints, length and number of new shoots and roots, were determined weekly from day 14 onwards. Destructive endpoints, dry-weight (DW) of main shoots, new shoots and new roots, were measured at the end of the experiment (t = 42 d).Metsulfuron-methyl exposure in particular inhibited new tissue formation but was not lethal to main shoots. On days 21 and 42 after start exposure, EC10/EC50 values for new tissues expressed in terms of peak concentration (=measured concentration during exposure periods of different length) showed large differences between exposure scenarios in contrast to EC10/EC50 values for days 21 and 42 expressed in terms of 21-d and 42-d TWA concentrations, respectively. At the end of the experiment (day 42), 42-d TWA ECx values were remarkably similar between exposure scenarios, while a similar trend could already be observed on day 21 for 21-d TWA ECx values. For the macrophyte M. spicatum and exposure to the herbicide metsulfuron-methyl the TWA approach seems to be appropriate to use in the risk assessment. However, the data from the toxicity experiment suggest that on day 21 also the absolute height of the pulse exposure played a (minor) role in the exposure - response relationships observed. 相似文献
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