Further directives stemming from the Framework Directive 76/464/EEC impose limit values or environmental quality standards to particular substances (around129), and the daughter Directives categorise these as either List I or Black list, which are also known as Red list substances in the UK. Grey list substances, as the name suggests are less harmful, although their concentrations in freshwater should be to a level at which the endemic fish populations may still be supported.

The UK has not adopted the same approach to black list substances as the other EU member states. Member states control such substances using limit values (LV's). The UK uses an approach involving the use of environmental quality standards (EQS's). LV's are imposed on an industrial sector basis and the local situation in the receiving water is ignored. EQS's take into account releases of pollution from all sources and consider the local environmental factors and are therefore more comprehensive.

The Environmental Protection (Prescribed Processes and Substances) Regulations 1991(as amended) give the Black list (referred to as Red List in the UK) substances whose release to water is subject to Integrated Pollution Control and now IPPC.