BS ISO 21115:2019 pdf free

BS ISO 21115:2019 pdf free.Water quality – Determination of acute toxicity of water samples and chemicals to a fish gill cell line (RTgill-W1)
sample is tested simultaneously in the presence of a reference chemical as positive control and as the effluent alone. For effluent testing with the positive control, the reference chemical, i.e. 3,4-DCA, is spiked to the effluent in a concentration range that is expected to yield a full concentration response curve and ECso values as indicated in Clause 10.
If the effluent itself is toxic, with a clear concentration-response curve, the positive control effluent with 3,4-DCA would also not result in a clear concentration-response curve and is, therefore, obsolete (e.g. see B.2, Table B.2 and Figure B.1, B, sample 6/site E). However, as many effluents are not acutely toxic, obtaining a concentration-response curve with 3,4-DCA will indicate proper functioning of the assay procedure if little or no toxicity stems from the effluent. A shift of the 3,4-DCA concentration response curve in the effluent matrix compared to L-15/ex to the right (i.e. lower part of curve is missing一0 % cell viability can no longer be observed) would indicate that the matrix lowers availability of the chemical to the cells but that the assay procedure worked [e.g. see B.2, Table B.2 and Figure B.1, A, sample 3/site B]. A shift of the concentration-response curve to the left (i.e. upper part of the curve is missing一100 % cell viability can no longer be observed) would indicate that the assay procedure worked but that the effluent by itself elicits a certain toxicity to the cells that is enhanced by the additional stress of the 3,4-DCA (e.g. see B.2, Table B.2 and Figure B.1, D, sample 17/site 0].
In some cases, precipitates may form upon addition of salts (see 8.3.2.3). This by itself does not preclude testing of the water sample as the formation of precipitates does not per se interfere with the assay (see also Reference [8]). If cell viability is affected by such a water sample, however, whether the effect is caused solely by the precipitates or linked to toxicants in the samples cannot be clearly distinguished.BS ISO 21115 pdf free download.