Biological assessment of the effects of a hog confinement farm on the North Skunk River in central Iowa

Abstract

Agriculture dominates the Iowa landscape and is a major polluter of local waterways. An appropriate method of assessing water degradation is the use of macroinvertebrates in biomonitoring. We conducted a comparative study of the aquatic macroinvertebrate communities located above and below a central Iowa hog confinement farm located on the North Skunk River. We identified macroinvertebrates belonging to 17 different families and classified each family according to a system in which macroinvertebrate taxa are listed under one of three pollution tolerance groupings: sensitive, moderately sensitive, and tolerant. Our results indicated poor water quality overall with a marginally non-significant difference between the upstream and downstream sampling sites. No significant difference was found in abundance or richness values of the samples. While little tangible evidence was gathered as to the direct effects of the hog confinement farm, it was apparent that the North Skunk River is highly polluted. The far-reaching effects of this pollution necessitate further study in order to better understand and prevent future pollution.