Protection of groundwater :Trigger levels
5.—(1) Significant adverse environmental effects, as referred to in regulations 16(3) and 17(5)(b), should be considered to have occurred in the case of groundwater, when an analysis of a groundwater sample shows a significant change in water quality.
(2) The level at which the effects referred to in sub-paragraph (1) are considered to have occurred (“the trigger level”) must be determined taking account of the specific hydrogeological formations in the location of the landfill and groundwater quality.
(3) The trigger level must be set out in the conditions of a landfill permit whenever possible.
(4) The observations must be evaluated by means of control charts with established control rules and levels for each downgradient well.
(5) The control levels must be determined from local variations in groundwater quality.