BS ISO 18187:2016 pdf download

BS ISO 18187:2016 pdf download.Soil quality — Contact test for solid samples using the dehydrogenase activity of Arthrobacter globiformis
1 Scope
This International Standard specifies a rapid method for assessing solid samples in an aerobic suspension, by determining the inhibition of dehydrogenase activity of Arthrobacter globiformis using the redox dye resazurin.
It is applicable for assessing the effect of water-soluble and solid matter bounded non-volatile contaminants of natural samples, such as soils and waste materials. The test  yields a result within 6 h and can therefore be used for screening potentially contaminated material.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 5667-15, Water quality — Sampling — Part 15: Guidance on the preservation and handling of sludge and sediment samples
ISO 10381-6, Soil quality — Sampling — Part 6: Guidance on the collection, handling and storage of soil under aerobic conditions for the assessment of microbiological processes, biomass and diversity in the laboratory
CEN/TR 15310-1, Characterization of waste — Sampling of waste materials — Part 1: Guidance on selection and application of criteria for sampling under various conditions
EN 14735, Characterization of waste — Preparation of waste samples for ecotoxicity tests
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1 contact time
exposure period of the bacteria to a suspension of solid matter
3.2 negative control
sample of a control substrate (3.6) with a mixture of known solutions [distilled water, medium B or inoculum (3.12)].
Note 1 to entry: It is used to standardize the analysis.
3.3 positive control
sample of a control substrate (3.6) with a mixture of known solutions [distilled water, medium B or inoculum (3.12)] and a reference substance
Note 1 to entry: It is used to check the sensitivity of the test organism.
4 Principle
The bacteria Arthrobacter globiformis is added to the solid material and incubated at (30 ± 1) °C for 2 h. After this contact time, the non-toxic redox dye resazurin is added. Due to the dehydrogenase activity, resazurin is transformed into resorufin, in the extracellular environment. [6] Resorufin can be detected fluorometrically (excitation at 535 nm, emission at 590 nm) in the presence of solid matter. The increase of resorufin is determined by measuring the fluorescence every 15 min for a period of 1 h. In order to determine the inhibition of the dehydrogenase activity, the rate of resorufin increase in the sample is compared with the rate of resorufin increase in the control. In the presence of toxic substances, an inhibition of dehydrogenase activity is expected. This is reflected by the reduction of resorufin production and subsequent lowering of fluorescence emission.