Assessment Comments
Assessment is based on results of water quality monitoring conducted from November 2000 through September 2001 by the Minnesota Pollution Control Agency.
Basis for Assessment
SUMMARY: The Class B(WW) aquatic life uses are assessed (monitored) as "not supported " due to levels of dissolved oxygen that violate state water quality criteria. Fish consumption uses remain "not assessed" due to the lack of fish contaminant monitoring in this river reach. The source of data for this assessment is the results of ambient water quality monitoring by the Minnesota Pollution Control Agency (MPCA) two miles NE of Ceylon, MN., from November 2000 through September 2001.
EXPLANATION: Results of ambient chemical/physical monitoring from MPCA suggest that the aquatic life uses are “not supported.” While none of the 10 samples collected from November 2000 through September 2001 violated state water quality criteria for temperature, pH, or ammonia nitrogen, three of the 10 samples (30%) violated state criteria for dissolved oxygen. These three violations are as follows: (1) January 24, 2001 (1.7 mg/l), (2) July 10, 2001 (2.9 mg/l), and (3) August 27, 2001. According to U.S. EPA guidelines for Section 305(b) reporting (U.S. EPA 1997b: page 3-17), a violation frequency for conventional parameters (including dissolved oxygen and pH) of more than 10% suggests an impairment of aquatic life uses; a violation frequency of greater than 25% suggests "non-support" of these uses.
Fish consumption uses remain "not assessed" due to the lack of fish contaminant monitoring in this stream segment.
