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| Title | Carbaryl Concentrations in Willapa Bay and Recommendations for Water Quality Guidelines | |||
| Month-Year Published | March 2001 | |||
| Online Availability |
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| Short Description |
The insecticide carbaryl (Sevin) was analyzed in water samples collected before and after its annual application to control burrowing shrimp on oyster beds in Willapa Bay. This was done to follow-up on 1996-97 data that appeared to show long-term persistence at about 0.7 ug/L. Results showed no evidence of a carbaryl background in the Willapa Bay water column. (Also see abstract below) | |||
| Publication Number | 01-03-005 | |||
| Author(s) | Johnson, A. | |||
| Print Availability | ||||
| Number of pages | 38 pp. + app (54 total) | |||
| Keywords | guidelines, recommendations, results, toxic, water, water quality | |||
| Subject Waterbodies |
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| Abstract | Long Description |
The insecticide carbaryl (Sevin) was analyzed in water samples collected before and after its annual application to control burrowing shrimp on oyster beds in Willapa Bay. This was done to follow-up on 1996-97 data that appeared to show long-term persistence at about 0.7 ug/L. Results showed no evidence of a carbaryl background in the Willapa Bay water column. Based on an analysis of toxicity data, the following guidelines were recommended for evaluating the significance of carbaryl residues in Willapa Bay water: 0.06 ug/L as a probable safe level for marine organisms; 0.1 - 0.7 ug/L as a potential effects threshold; and 3.0 ug/L as being equivalent to an EPA acute water quality criterion. Data are presented that show carbaryl concentrations were at or below 0.1 ug/L after the end of the July 5-31, 2000 spray period, but that concentrations were in the potential effects threshold range at locations several miles from oyster beds soon after large areas were treated. Comparable low-level data are not available to show what the concentrations are closer to treated beds during or within a few days of applications. |
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