COHPOtfENT NO. 2 



WATER QUALITY /BIOLOGICAL CRITERIA AND BIOASSESSMPsT IP - 7 

 Prepared by: Loren L. Bahls, Ph.D. 

 Montana Department of Health and Environmental Sciences^ 



SUMMARY 



This component will establish baseline water quality and biological 

 conditions in a representative sample of unimpaired or least- 

 impaired wetlands in Montana. This information will be used to 

 develop chemical and biological water quality criteria for Montana 

 wetlands and bioassessment techniques that will be used to measure 

 impairment to wetlands that have been exposed to environmental 

 contamination and other stressors. 



BACKGROUND 



Relatively little information is available regarding water quality 

 in Montana wetlands. Elevated concentrations of salts, trace 

 elements, and pesticides are the principal water quality concerns 

 in Montana wetlands (MDHES 1990) . Investigations of these 

 contaminants have been conducted by the Montana Department of Fistv, 

 Wildlife and Parks, Montana Bureau of Mines, U. S. Geological 

 Survey, and U. S. Fish and Wildlife Service (see REFERENCES for 

 partial listing) . 



Wetlands are implicitly included in the definition of "Surface 

 Waters* in Montana's Surface Water Quality Standards. Although 

 the general prohibitions in these standards serve well to protect 

 wetlamd water quality, specific criteria and waterbody 

 classifications, including designated uses, are often technically 

 incorrect for wetlands. 



Biological sxirveys of Montana wetlands tend to emphasize aquatic 

 and semi-aquatic macrophytes, birds and mammals (e.g., Habecic 

 1988) . While these are the most conspicuous inhabitants of 

 wetlands, they are among the least sensitive and responsive to 

 changes in water quality. Sanville (1991) suggests that microbiota 

 (algae) and macro invertebrates may be used as surrogate measures of 

 the general health and ecological integrity of wetlands. These 

 "groups are very sensitive to changes in water quality and other 

 ecological perturbations, and serve as useful indicators of 

 ecosystem health (Plafkin et al. 1989) . 



The Montana Department of Health and Environmental Sciences 

 routinely uses the structure and composition of benthic algae 

 (periphyton) and benthic macro invertebrate communities to assess 

 water quality in rivers and streams. A recent statewide survey of 

 the structure and composition of periphyton and macro invertebrate 

 communities in selected least-impaired reference streams will 

 driable the Department to develop ecoregion-specif ic biological 

 criteria and bioassessment protocols for lotic ecosystems in 

 Montana (Bahls et al. in prep.). 



