23. Minnesota Rules, §7050.0170. The rule states In full: 



The waters of the state may, in a state of nature, 

 have some characteristics or properties approaching or 

 exceeding the limits specified in the water quality 

 stemdards. The standards shall be construed as 

 limiting the addition of pollutants of human activity 

 to those of natural origin, where such be present, so 

 that in total the specified limiting concentrations 

 will not be exceeded in the waters by reason of such 

 controllaQjle additions. Where the background level of 

 the natxiral origin is reasoneO^ly defincible and 

 normality is higher than the specified stsmdards the 

 natural level may be used as the stzmdard for 

 controlling the addition of pollutants of human 

 activity which are comparable in nature and 

 significance with those of natural origin. The natural 

 background level may be used instead of the specified 

 water quality stemdard as a maximum limit of the 

 addition of pollutants, in those instances where the 

 natural level is lower them the specified standard and 

 reasoneOsle justification exists for preserving the 

 quality to that found in a state of nature. 



24. No. 83-1352-1 (Chancery Coiirt, 7th Division, Davidson 

 Coxinty, 1984) (unpublished opinion) . 



25. These criteria are at 401 K.A.R. 5:031, §2(4) and §4(1) (c), 

 respectively. 



26. Ohio ildmin. Code, §3745-32-05. 



27. Ohio Admin. Code, §3745-1-05 (C) . 



28. Copies of Ohio's review guidelines are availedale from Ohio 

 EPA, 401 Coordinator, Division of Water Quality Monitoring and 

 Assessment, P.O. Box 1049, Columbus, Ohio 43266-0149. 



29. 40 CFR §131.12. 



30. 48 Fed. Reg. 51,400, 51,403 (1983) (preamble) . 



31. Kentucky Water Quality Standards, Title 401 K.A.R. 5:031, §7. 



32. Minnesota Rules, §7050.0180, Subpart 7. 



33. 314 Code of Massachusetts Regulation, §4.04(4). 



34. Minnesota Rules, §7050.0180, Subpart 9. 



35. H.R. Rep. No. 91-127, 91st Cong., 1st Sess. 6 (1969). 



iii 



