8.—(1) Subject to the conditions in paragraphs (2) and (3), the Department may, in relation to one or more categories of surface water, apply an environmental quality standard for a matrix other than the matrix specified in column 9 of Table 47 of Part 2 of Schedule 1 or, if applicable, an environmental quality standard for a biota taxon other than those specified in that Table.
(2) The first condition is that the Department applies either—
(a)the relevant environmental quality standard laid down in Table 47 of Part 2 of Schedule 1; or
(b)if there is no relevant environmental quality standard laid down in that Table for the alternative matrix or biota taxon, an environmental quality standard that offers at least the same level of protection as that provided by an environment quality standard established for a matrix or biota taxon—
(i)in Table 47 of Part 2 of Schedule 1; and
(ii)according to technical knowledge and expert judgement, is equivalent to the alternative matrix or biota taxon.
(3) The second condition is that the Department's method of analysis for the chosen matrix or biota taxon fulfils the minimum performance criteria laid down in Article 4 of Directive 2009/90/EC. Where those criteria are not met for any matrix, the monitoring must be carried out using the best available techniques not entailing excessive costs and the method of analysis for the relevant substance must perform at least as well as that available for the matrix specified in regulation 7.