Anthropogenic impacts on the quality of streambed sediments in the lower Sacramento River watershed, California.

To investigate the occurrence of contaminants and to assess their toxicity potential to benthic organisms, streambed sediments were collected from three agricultural and one urban influenced small waterways in the lower Sacramento River watershed and analyzed for PAHs, organochlorine (OC) and organophosphorus (OP) pesticides, pyrethroids, and metals. These sites had low benthic biotic index scores in earlier field surveys. The occurrence patterns of these contaminants and iron normalized enrichment factors of metals reflect the land use patterns around study sites.

Statewide investigation of the role of pyrethroid pesticides in sediment toxicity in California's urban waterways.

A statewide investigation of urban creek sediment toxicity was conducted in California in recognition of increased incidences of toxicity linked to pyrethroid pesticides. The goals were to examine the spatial occurrence and magnitude of sediment toxicity in California urban creeks, and to examine the role of pyrethroids in toxic urban creek sediment samples. After a preliminary screening of 90 sites, 30 creeks were sampled in eight geographical regions.

Monitoring of diazinon concentrations and loadings, and identification of geographic origins consequent to stormwater runoff from orchards in the Sacramento River watershed, U.S.A.

Diazinon contamination of California's rivers has resulted in placing several rivers on the federal Clean Water Act 303d list of impaired waterways. Impaired water body listing requires the development of Total Maximum Daily Loads (TMDL). Previous studies identified stormwater related diazinon pulses in California rivers.