Effects observed within one generation disregard potential detrimental effects that may appear across generations. Previously we have developed a two generation Daphnia magna reproduction test using the OECD TG 211 protocol with a few amendments, including initiating the second generation with third brood neonates produced from first generation individuals. Here we showed the results of an inter-laboratory calibration exercise among 12 partners that aimed to test the robustness and consistency of a two generation Daphnia magna reproduction test. Pyperonyl butoxide (PBO) was used as a test compound. Following experiments, PBO residues were determined by TQD-LC/MS/MS. Chemical analysis denoted minor deviations of measured PBO concentrations in freshly prepared and old test solutions and between real and nominal concentrations in all labs. Other test conditions (water, food, D. magna clone, type of test vessel) varied across partners as allowed in the OECD test guidelines. Cumulative fecundity and intrinsic population growth rates (r) were used to estimate “No observed effect concentrations “NOEC using the solvent control as the control treatment. EC10 and EC-50 values were obtained regression analyses. Eleven of the twelve labs succeeded in meeting the OECD criteria of producing >60 offspring per female in control treatments during 21 days in each of the two consecutive generations. Analysis of variance partitioning of cumulative fecundity indicated a relatively good performance of most labs with most of the variance accounted for by PBO (56.4%) and PBO by interlaboratory interactions (20.2%), with multigenerational effects within and across PBO concentrations explaining about 6% of the variance. EC50 values for reproduction and population growth rates were on average 16.6 and 20.8% lower among second generation individuals, respectively. In summary these results suggest that the proposed assay is reproducible but cumulative toxicity in the second generation cannot reliably be detected with this assay.

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Russian Federationᮀ Purpose: To analyze the long-term effects of exposure to low-dose γ-irradiation on survival and life span in directly irradiated Daphnia magna and their offspring. Materials and methods: One-day-old Daphnia magna were exposed to 10, 100 and 1000 mGy of acute γ-rays. The life-span of irradiated and control animals, as well as their non-exposed progeny was analyzed. Results: Irradiation at dose of 100 and 1000 mGy resulted in a significant decrease in the life span of irradiated Daphnia. The data presented here also show that the survival of non-exposed first-generation offspring of irradiated parents is significantly compromised, thus implying the presence of transgenerational effects. Conclusion: The results of our study show that low-dose irradiation significantly reduces the life-span of directly exposed Daphnia and their first-generation offspring. The observed compromised viability is most likely attributed to non-targeted effects of ionizing radiation.

Electromagnetic radiation at the mobile connection frequency (1 GHz) at maximum energy flow density (10 microW/cm(2)) permitted in Russia causes serious functional disorders in the studied unicellular hydrobionts infusoria Spirostomum ambiguum: reduction of their spontaneous motor activity. The form of biological reaction is uncommon: the effect is threshold, overall, and does not depend on the duration of microwave exposure.

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From tangled banks to toxic bunnies; a reflection on the issues involved in developing an ecosystem approach for environmental radiation protection Mothersill, CE

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