(1) Control of the migration of hazardous waste and hazardous waste constituents from the treated area into the ground water;
(2) Control of the release of contaminated run-off from the facility into surface water;
(3) Control of the release of airborne particulate contaminants caused by wind erosion; and
(4) Compliance with § 265.276 concerning the growth of food-chain crops.
(b) The owner or operator must consider at least the following factors in addressing the closure and post-closure care objectives of paragraph (a) of this section:
(1) Type and amount of hazardous waste and hazardous waste constituents applied to the land treatment facility;
(2) The mobility and the expected rate of migration of the hazardous waste and hazardous waste constituents;
(3) Site location, topography, and surrounding land use, with respect to the potential effects of pollutant migration (e.g., proximity to ground water, surface water and drinking water sources);
(4) Climate, including amount, frequency, and pH of precipitation;
(5) Geological and soil profiles and surface and subsurface hydrology of the site, and soil characteristics, including cation exchange capacity, total organic carbon, and pH;
(6) Unsaturated zone monitoring information obtained under § 265.278; and
(7) Type, concentration, and depth of migration of hazardous waste constituents in the soil as compared to their background concentrations.
(c) The owner or operator must consider at least the following methods in addressing the closure and post-closure care objectives of paragraph (a) of this section:
(1) Removal of contaminated soils;
(2) Placement of a final cover, considering:
(i) Functions of the cover (e.g., infiltration control, erosion and run-off control, and wind erosion control); and
(ii) Characteristics of the cover, including material, final surface contours, thickness, porosity and permeability, slope, length of run of slope, and type of vegetation on the cover; and
(3) Monitoring of ground water.
(d) In addition to the requirements of subpart G of this part, during the closure period the owner or operator of a land treatment facility must:
(1) Continue unsaturated zone monitoring in a manner and frequency specified in the closure plan, except that soil pore liquid monitoring may be terminated 90 days after the last application of waste to the treatment zone;
(2) Maintain the run-on control system required under § 265.272(b);
(3) Maintain the run-off management system required under § 265.272(c); and
(4) Control wind dispersal of particulate matter which may be subject to wind dispersal.
(e) For the purpose of complying with § 265.115, when closure is completed the owner or operator may submit to the Regional Administrator certification both by the owner or operator and by an independent, qualified soil scientist, in lieu of a qualified Professional Engineer, that the facility has been closed in accordance with the specifications in the approved closure plan.
(f) In addition to the requirements of § 265.117, during the post-closure care period the owner or operator of a land treatment unit must:
(1) Continue soil-core monitoring by collecting and analyzing samples in a manner and frequency specified in the post-closure plan;
(2) Restrict access to the unit as appropriate for its post-closure use;
(3) Assure that growth of food chain crops complies with § 265.276; and
(4) Control wind dispersal of hazardous waste.