1. Herbicide Residues in Fish Tissues Brian Finlayson Pesticide Investigations Unit California Department of Fish and Game

2. Evaluation of Herbicides n 1999 –hexazinone –sulfometuron-methyl –glyphosate –triclopyr –2,4-D –atrazine n 2000 –atrazine –hexazinone –triclopyr –hexazinone

3. Assessment Factors n Water solubility n Persistence n BCF (biological concentration factor) n Application technique

4. Atrazine n Low BCF (<100) n Slightly water soluble (28 ppm) n Retention of herbicide residues (easily absorbed) n Highly persistent in water and soil (> 1 yr) n Ground application

5. 2,4-D n Ester forms have relatively high BCF n Easily absorbed by organisms n Chronic toxicity in mammals (cancer/birth defects) n Low conc found in surface water n Not persistent n Aerial application

6. Triclopyr n Highly soluble in water n BCF for ester formulations may be high n Low persistence in organisms n Detected in 2,4-D analysis (free)

7. Sample Parameters n whole body analyses n resident riffle sculpin (composite) n young-of-year salmonids (composite) n 10 samples per site per species n double wrapped in aluminum foil n dry ice shipment n late spring (following applicat1on)

8. Analyses Analyses n $750/sample for 2,4-D and triclopyr n $750/sample for atrazine n 100 grams per sample n QA/QC procedures –duplicate analyses –matrix spikes