Des Moines River IA 04-LDM-1003

Assessment Comments

Assessment is based on (1) results of IDNR ambient monthly monitoring near Keokuk and (2) fish tissue monitoring near Croton.

Basis for Assessment

Used assessment of support of the Class B(WW) aquatic life uses developed for the 1996 report, in combination with results of DNR quarterly monitoring S of Keokuk from October 1995 through September 1997, to assess support of the Class B(WW) aquatic life uses as FST.   No violations of WQ criteria for either conventional or toxic pollutant occurred during this two year period.   In addition, used results of the the three non-flow affected samples analyzed for fecal coliform bacteria over the 1996-97 period to assess support of the Class A primary contact uses as FST:  levels of fecal coliforms in the three samples ranged from 20 to 150 orgs/100 ml with a geometric mean of 55.   Based on methods for assessing support of primary contact uses as described in 1998 Section 305(b) reporting guidelines (p.  3-34), the data from this station suggest full support of these uses.   Due to lack of sufficient number of samples to make "monitored" assessments, the assessments of use support in this reach are considered "evaluated."  Levels of all fish contaminants in the RAFT fish tissue sample of whole- fish carp collected near Keosauqua in 1996 were < 1/2 of FDA action levels and DNR levels of concern.   Thus, assess support of the fish consumption uses as "fully supporting" (=FS).