CALIFORNIA agencies DPR and CA-IWMB held a stakeholder mtg in Sacramento concerning regulating clopyralid residues in composts. CCQC gave results of recently completed analyses for clopyralid in 26 composts. Dr. Brinton of Woods End presented research conducted on degradation and soil-plant effects. Brinton concluded that clopyralid does degrade in compost and exhibits dissipation rates similar to reported soil half-lives. The data appears to refute statements by the press that clopyralid does not decompose in compost. Woods End also disclosed results of plant trials determining FOEL thresholds based on various compost uses. Threshold levels for damage varied and some were significanly higher than values assumed previously based on DOW’s own soil work. Brinton’s lab posed a general rule of thumb that there are not likely to be adverse field effects from tainted composts containing as much as 50ppb clopyralid when used at “normal application rates”. CCQC and other participants expressed concern with the overall findings. “This data surprises me very much” said Will Bakx of CCQC. “We’ve operated on the assumption of much lower plant damage thresholds, and these results seem to give a rosy picture”. The data reported by CCQC from its own recent analytical survey of California composts showed that the highest clopyralid residue levels were 16ppb, which according to the findings presented by Woods End would be insufficient to cause plant harmful effects. Brinton expressed the view that the compost industry may have over-estimated its risk, essentially implying that all compost is used at a “100% application rate”. Brinton pointed to other scientifc studies that appear to confirm his findings such as WSU-Puyallup) . The mtg sets the stage for th Apr. 1, 2003 deadline by CA-DPR to act on a legislative mandate AB 2356 to set limits for herbicide exposure via compost. The journal Inside Cal-EPA reported on the meeting Friday, Mar 21. The March issue of Composting News carries a full interview with Brinton. Free Reprints of both full stories are seen at the Woods End store.