These Regulations prescribe quality standards to be applied by local and sanitary authorities when licensing discharges of effluents containing carbon tetrachloride (CC14), DDT and pentachlorophenol to waters or to sewers under the provisions of the Local Government (Water Pollution) Act, 1977 as amended by the Local Government (Water Pollution) (Amendment) Act, 1990. A local authority or sanitary authority shall ensure that the best technical means are used where necessary for the elimination of pollution in granting a licence for the discharge of trade effluent from a new plant. A licence in respect of trade effluent shall be reviewed at least every four years. A local authority or sanitary authority shall ensure as far as possible that the granting of a licence will not result in an increase in the pollution, by the substances in respect of which quality standards are prescribed in these Regulations, of other environmental media, in particular soil and air.