Ecotoxicology studies are performed to assess the impact of the contamination of compounds on various ecosystems. The studies are conducted by following the Principles of Good laboratory Practices. The studies are conducted in accordance with the standard operating procedures of test facility and mutually agreed study plans and amendments. Instruments required in the experiments are well equipped and procured from the authenticated vendors having ISO/NABL certification. Internal as well as external calibrations are also performed at regular intervals.
The aquatic testing at our facility includes the following studies:
OECD 202
Young daphnids, aged less than 24 hours at the start of the test, are exposed to the test substance at a range of concentrations for a period of 48 hours. Immobilisation is recorded at 24 hours and 48 hours and compared with control values. The results are analysed in order to calculate the EC50 . Determination of the EC50 at 24h is optional.
OECD 211
The primary objective of the test is to assess the effect of chemicals on the reproductive output of Daphnia magna. To this end, young female Daphnia (the parent animals), aged less than 24 hours at the start of the test, are exposed to the test substance added to water at a range of concentrations. The test duration is 21 days. At the end of the test, the total number of living offspring produced is assessed. Reproductive output of the parent animals can be expressed in other ways (e.g. number of living offspring produced per animal per day from the first day offspring were observed) but these should be reported in addition to the total number of living offspring produced at the end of the test.
OECD 203
The fish are exposed to the test chemical for a period of 96 hours, under either static, semi-static or flow-through conditions. Mortalities and visible abnormalities related to appearance and behaviour are recorded. Where possible, the concentrations to kill 50% of the fish (LC50) are determined.
OECD 210
The early-life stages of fish are exposed to a range of concentrations of the test chemical dissolved in water. Flow-through conditions are preferred; however, if it is not possible semi static conditions are acceptable. For details the OECD Guidance Document No. 23 on aquatic toxicity testing of difficult substances and mixtures should be consulted . The test is initiated by placing fertilised eggs in test chambers and is continued for a species-specific time period that is necessary for the control fish to reach a juvenile life-stage. Lethal and sub lethal effects are assessed and compared with control values to determine the lowest observed effect concentration (LOEC) in order to determine the (i) no observed effect concentration (NOEC) and/or (ii) ECx (e.g. EC10, EC20) by using a regression model to estimate the concentration that would cause a x % change in the effect measured. Reporting of relevant effect concentrations and parameters may depend upon the regulatory framework. The test concentrations should bracket the ECx so that the ECx comes from interpolation rather than extrapolation.
OECD 201
The purpose of this test is to determine the effects of a substance on the growth of freshwater microalgae and/or cyanobacteria. Exponentially growing test organisms are exposed to the test substance in batch cultures over a period of normally 72 hours. In spite of the relatively brief test duration, effects over several generations can be assessed. Exponentially growing cultures of Pseudokircheneriella subcapitata are exposed to the test substance at the concentration of 100 mg/L in limit test, or at the range of 5 concentration in definitive test (results in ECx values).
