1. (1) An owner or operator of a new Class II or Class IV landfill unit, or a lateral expansion of an existing Class II or Class IV landfill unit, may construct it only if the owner or operator has obtained department approval of a design that either:

   1. (a) ensures that the concentration values listed in Table 1 of this rule will not be exceeded at the relevant point of compliance, as specified by the department:

      1. (i) for a Class II landfill unit, in the uppermost aquifer; or
      2. (ii) for a Class IV landfill unit, in an underground drinking water source; or
   2. (b) utilizes a composite liner and a leachate collection and removal system that is designed and constructed to maintain less than a 30-cm depth of leachate over the liner.

2. (2) When determining whether a design complies with (1)(a), the department shall consider at least the following factors:

   1. (a) the hydrogeologic characteristics of the facility and surrounding land;
   2. (b) the climatic factors of the area; and
   3. (c) the volume and physical and chemical characteristics of the leachate.

3. (3) The relevant point of compliance (RPOC) specified by the department pursuant to (1)(a) may not be more than 150 meters from the waste management unit boundary and must be on land owned by the owner of the Class II or Class IV landfill unit. In determining the RPOC, the department shall consider at least the following factors:

   1. (a) the hydrogeologic characteristics of the facility and surrounding land;
   2. (b) the volume and physical and chemical characteristics of the leachate;
   3. (c) the quantity, quality, and direction of flow of ground water;
   4. (d) the proximity and withdrawal rate of the ground water users;
   5. (e) the availability of alternative drinking water supplies;
   6. (f) the existing quality of the ground water, including other sources of contamination and their cumulative impacts on the ground water, and whether the ground water is currently used or reasonably expected to be used for drinking water;
   7. (g) public health, safety, and welfare effects; and

   8. (h) practicable capability of the owner or operator.

      Table 1

      Chemical	MCL (mg/L)
      Arsenic	0 .05
      Barium	1 .0
      Benzene	0 .005
      Cadmium	0 .01
      Carbon tetrachloride	0 .005
      Chromium (hexavalent)	0 .05
      2,4-Dichlorophenoxy acetic acid	0 .1
      1,4-Dichlorobenzene	0 .075
      1,2-Dichloroethane	0 .005
      1,1-Dichloroethylene	0 .007
      Endrin	0 .0002
      Fluoride	4
      Lindane	0 .004
      Lead	0 .05
      Mercury	0 .002
      Methoxychlor	0 .1
      Nitrate	10
      Selenium	0 .01
      Silver	0 .05
      Toxaphene	0 .005
      1,1,1-Trichloromethane	0 .2
      Trichloroethylene	0 .005
      2,4,5-Trichlorophenoxy acetic acid	0 .01
      Vinyl Chloride	0 .002

Authorizing statute(s): 75-10-204, MCA

Implementing statute(s): 75-10-204, MCA

History: NEW, 2010 MAR p. 317, Eff. 2/12/10.