(a) Ammonia. - (i) The toxicity of ammonia varies with pH and temperature and the applicable limitations are included in the tables in Appendix C of these regulations. The numeric ammonia criteria in Appendix C apply to all Class 1, 2AB, 2A, 2B and 2C waters.
- (ii) In all Class 2D and 3 waters, concentrations of ammonia attributable to or influenced by human activities shall not be present in concentrations which could result in harmful acute or chronic effects to aquatic life, or which would not fully support existing and designated uses.
(b) Specific numeric standards for a number of toxicants are listed in the "Aquatic Life Acute Value" and "Aquatic Life Chronic Value" columns in Appendix B of these regulations. These standards apply to all Class 1, 2 and 3 waters. For these pollutants, the chronic value (four (4) day average concentration) and the acute value (one (1) hour average concentration) shall not be exceeded more than once every three (3) years.
(c) Others. For those pollutants not listed in Appendix B or C of these regulations, maximum allowable concentrations on Class 1, 2 and 3 waters shall be determined through the bioassay procedures outlined in the references listed in Appendix E of these regulations.
(d) In certain waters, the criteria listed in Appendix B or C of these regulations may not be appropriate due to unique physical or chemical conditions. In such cases, acute and chronic values may be determined using the site-specific procedures outlined in the references listed in Appendix E or other scientifically defensible methods.
(e) Aquatic pesticides specifically designed to kill, repel or mitigate aquatic pest problems (e.g. mosquito larvae or heavy plant growth in irrigation ditches) may be added to surface waters of the state if the use and application is in compliance with the following: - (i) The pesticide used is a product which has been registered with the EPA and the Wyoming Department of Agriculture for use in the state, in accordance with W.S. 35-7-356;
- (ii) The application is conducted by a person licensed by the Wyoming Department of Agriculture to purchase and apply restricted use pesticides in the state;
- (iii) All applications of aquatic pesticides must be administered in accordance with label directions. However, compliance with label directions shall not exempt any person or agency from the penalty provisions of W.S. 35-11-901 should non-target species or non-target areas be affected.
(f) This section shall not apply to the use of fish toxicants if the use and application is in compliance with the following: - (i) The pesticide used is a product which has been registered with the EPA and the Wyoming Department of Agriculture for use in the state, in accordance with W.S. W.S. 35-7-356;
- (ii) The application is conducted by a person licensed by the Wyoming Department of Agriculture to purchase and apply restricted use pesticides in the state;
- (iii) All applications of fish toxicants must be administered in accordance with label directions. However, compliance with label directions shall not exempt any person or agency from the penalty provisions of W.S. 35-11-901 should non-target species or non-target areas be affected.
- (iv) The Wyoming Game and Fish Department may apply fish toxicants to any surface water of the state provided that prior notice is made to the department and after receipt of verification from the Water Quality Division that the proposed application is in compliance with this section.
- (v) The National Park Service, as the wildlife management agency in Yellowstone National Park, may apply fish toxicants to surface waters within Yellowstone National Park for the purpose of killing or controlling fish provided that prior notice is made to the department and after receipt of a verification from the Water Quality Division that the proposed application is in compliance with this section. Approval from the Wyoming Game and Fish Department is also required prior to application of fish toxicants to waters which flow into surface waters of the state outside of Yellowstone National Park.
- (vi) Private certified pesticide applicators for restricted use pesticides may apply fish toxicants only to waters located entirely on private property where there is no surface outlet to waters of the state provided that prior notice is made to the department and after receipt of verification from the Water Quality Division that the proposed application is in compliance with this section. Approval, including any necessary permits, from the Wyoming Game and Fish Department is also required prior to application of fish toxicants to insure protection of fish and wildlife resources.
- (vii) Pesticide applications must be conducted in a manner that minimizes to the extent practicable, the magnitude of any change in the concentration of the parameters affected by the activity and the length of time during which any change may occur. The application must include measures that prevent significant risk to public health and ensure that existing and designated uses of the water are protected and maintained upon the completion of the activity.
- (viii) Except for the circumstances described in (i) through (vii) above, no other agency or person may apply fish toxicants in any water of the state.
020-1 Wyo. Code R. § 1-21