Division 1.8.1 Equipment

The test may be conducted in conical or cylindrical flasks of appropriate capacity (e.g. 0,5 or 1,0 litre) closed with silicone or rubber stoppers, or in serum flasks with CO₂-tight lids (e.g. with butyl rubber septa). Another option is to perform the test by use of multiple flasks and to harvest whole flasks, at least in duplicate, at each sample interval (see last paragraph in section 1.8.9.1). For non-volatile test substances that are not radiolabelled, gas-tight stoppers or lids are not required; loose cotton plugs that prevent contamination from air are suitable (see second paragraph in section 1.8.9.1). Slightly volatile substances should be tested in a biometer-type system with gentle stirring of the water surface. To be sure that no bacterial contamination occurs, optionally the vessels can be sterilised by heating or autoclaving prior to use. In addition, the following standard laboratory equipment is used:

• shaking table or magnetic stirrers for continuous agitation of the test flasks,

• centrifuge,

• pH meter,

• turbidimeter for nephelometric turbidity measurements,

• oven or microwave oven for dry weight determinations,

• membrane filtration apparatus,

• autoclave or oven for heat sterilisation of glassware,

• facilities to handle ¹⁴C-labelled substances,

• equipment to quantify ¹⁴C-activity in samples from CO₂-trapping solutions and, if required, from sediment samples,

• analytical equipment for the determination of the test (and reference) substance if specific chemical analysis is used (e.g. gas chromatograph, high-pressure liquid chromatograph).