Bob White Lake IA 05-CHA-1338

Assessment Comments

Basis for Assessment

Both fishable and swimmable uses were assessed as "not supported" (NS) for the following reasons:  (1) results of monitoring in 1990 show that average levels of secchi depth, total-P, and TSS were worse than overall averages for the 86 SPO impoundments sampled in 1990 and 1992 +/- 1 SD; average levels for all these parameters were in the worst 10% of SPO impoundments sampled; no other of the 116 SPOLs had these three parameters in the worst 10%; (2) levels of swimming and fishing reported in Bachmann et al.  (1994) are relatively low but are not in the lowest 10%; (3) lake has a moderately high sedimentation rate (3.1 cm/yr) and rel.  short life expectancy (50 years) for SPO impoundments in Iowa.   Thus, despite the levels of swimming and fishing use reported, the data suggest that this lake has some of the poorest WQ of any SPOL in Iowa.   All fish contaminants from  the composite sample of channel catfish fillets sampled for the 1991 EPA/DNR fish tissue (RAFT) monitoring program were less than 1/2 of the respective FDA action levels.   Thus, fish consumption uses were assessed as "fully supported."