3.—(1) Subject to sub-paragraphs (2) and (3), “groundwater activity” means any of the following—
(a)the discharge of a pollutant that results in the direct input of that pollutant to groundwater;
(b)the discharge of a pollutant in circumstances that might lead to an indirect input of that pollutant to groundwater;
(c)any other discharge that might lead to the direct or indirect input of a pollutant to groundwater;
(d)an activity in respect of which a notice under paragraph 10 has been served and has taken effect;
(e)an activity that might lead to a discharge mentioned in paragraph (a), (b) or (c), where that activity is carried on as part of the operation of a regulated facility of another class.
(2) A discharge or an activity that might lead to a discharge is not a “groundwater activity” if the discharge is—
(a)made, or authorised to be made, by or under any prescribed statutory provision, or
(b)of trade effluent or sewage effluent from a vessel.
(3) The regulator may determine that a discharge, or an activity that might lead to a discharge, is not a groundwater activity if the input of the pollutant—
(a)is the consequence of an accident or exceptional circumstances of natural cause that could not reasonably have been foreseen, avoided or mitigated,
(b)is or would be of a quantity and concentration so small as to obviate any present or future danger of deterioration in the quality of the receiving groundwater, or
(c)is or would be incapable, for technical reasons, of being prevented or limited without using—
(i)measures that would increase risks to human health or to the quality of the environment as a whole, or
(ii)disproportionately costly measures to remove quantities of pollutants from, or otherwise control their percolation in, contaminated ground or subsoil.
(4) The regulator must keep a record of all determinations under sub-paragraph (3).