BS ISO 21285:2019 pdf download – Soil quality — Inhibition of reproduction of the soil mite (Hypoaspis aculeifer) by soil contaminants

BS ISO 21285:2019 pdf download – Soil quality — Inhibition of reproduction of the soil mite (Hypoaspis aculeifer) by soil contaminants 4 Principle Adult females are exposed to the soil to be tested and the effects on reproduction measured are compared to those observed for females exposed to a control soil. If appropriate, effects based on exposure to a dilution range of contaminated soil and control soil or a range of concentrations of a test substance mixed into control soil are determined. Test mixtures are prepared at the start of the test and are not renewed within the test period. The test is started with 10 adult females per test vessel. Males are not introduced in the test, because experience has shown that females mate immediately or shortly after hatching from the deutonymph stage, if males are present. As the females are introduced into the test about 7 d after they have reached the adult stage, the females can be considered as already mated (Annex A and Annex E). The test runs until the first offspring have reached the deutonymph stage. At 20 °C the exposure time ends at day 14 after introducing the females (day 0), followed by two days of extraction. The number of surviving females and the number of juveniles per test vessel are determined. The reproductive output of the mites exposed to the test mixtures is compared to that of the controls in order to determine the concentrations which cause no effects on mortality and reproduction (NOER/NOEC) and the concentration resulting in x % reduction of juveniles hatched from eggs compared to the control (ER x /EC x ) respectively, depending on the experimental design (see 7.1.3). In case there is no prior knowledge of the dilution/concentration of the soil to be tested or the test substance likely to have an effect, then it is useful to conduct the test in two steps: — A range-finding test on reproduction is carried out, to give an indication of the effect dilution/concentration, and the dilution/concentration giving no mortality (NOER/NOEC). Dilutions/concentrations to be used in the definitive test can then be selected; — the definitive test on reproduction to determine sublethal effects of (dilutions of) contaminated soil or the concentration of a substance which, when evenly mixed into the standard soil, causes no significant effects on numbers of offspring hatched from eggs compared with the control (NOER/NOEC), and the...