Section 264.93 - Hazardous constituents(a) The Regional Administrator will specify in the facility permit the hazardous constituents to which the ground-water protection standard of § 264.92 applies. Hazardous constituents are constituents identified in appendix VIII of part 261 of this chapter that have been detected in ground water in the uppermost aquifer underlying a regulated unit and that are reasonably expected to be in or derived from waste contained in a regulated unit, unless the Regional Administrator has excluded them under paragraph (b) of this section.(b) The Regional Administrator will exclude an appendix VIII constituent from the list of hazardous constituents specified in the facility permit if he finds that the constituent is not capable of posing a substantial present or potential hazard to human health or the environment. In deciding whether to grant an exemption, the Regional Administrator will consider the following: (1) Potential adverse effects on ground-water quality, considering:(i) The physical and chemical characteristics of the waste in the regulated unit, including its potential for migration;(ii) The hydrogeological characteristics of the facility and surrounding land;(iii) The quantity of ground water and the direction of ground-water flow;(iv) The proximity and withdrawal rates of ground-water users;(v) The current and future uses of ground water in the area;(vi) The existing quality of ground water, including other sources of contamination and their cumulative impact on the ground-water quality;(vii) The potential for health risks caused by human exposure to waste constituents;(viii) The potential damage to wildlife, crops, vegetation, and physical structures caused by exposure to waste constituents;(ix) The persistence and permanence of the potential adverse effects; and(2) Potential adverse effects on hydraulically-connected surface water quality, considering: (i) The volume and physical and chemical characteristics of the waste in the regulated unit;(ii) The hydrogeological characteristics of the facility and surrounding land;(iii) The quantity and quality of ground water, and the direction of ground-water flow;(iv) The patterns of rainfall in the region;(v) The proximity of the regulated unit to surface waters;(vi) The current and future uses of surface waters in the area and any water quality standards established for those surface waters;(vii) The existing quality of surface water, including other sources of contamination and the cumulative impact on surface-water quality;(viii) The potential for health risks caused by human exposure to waste constituents;(ix) The potential damage to wildlife, crops, vegetation, and physical structures caused by exposure to waste constituents; and(x) The persistence and permanence of the potential adverse effects.(c) In making any determination under paragraph (b) of this section about the use of ground water in the area around the facility, the Regional Administrator will consider any identification of underground sources of drinking water and exempted aquifers made under § 144.8 of this chapter.47 FR 32350, July 26, 1982, as amended at 48 FR 14294, Apr. 1, 1983