SITE INFORMATION AND CORRESPONDENCE_CASE 2

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' Ms. Jeanine Townsend _ 5_� .,,&Of 4 March 2009 Bis(2-ethyl hexyl)phthalate As discussed in Section IV.C.3.g. of the Fact Sheet (p. F-32), there is insufficient information to conduct a reasonable potential analysis due to uncertainty in the sample results. The CTR criterion for bis(2-ethylhexyl) phthalate is 1.8 pg/L. Of the four samples available at the time the permit was adopted, only one gave any indication that the effluent exceeded the CTR criterion, and there is evidence in the record that this sample result is suspect. In this case, there were four samples collected in 2002. Although there were detections of bis(2-ethylhexyl) phthalate, the only value greater than the CTR criterion was an estimated value (i.e. j-flagged). As indicated on the lab sheets, duplicate effluent samples were collected and sent to two separate labs to measure for bis(2-ethylhexyl) phthalate. The two labs were Montgomery Watson Laboratories and Caltest Laboratories. Caltest reported a j-flagged value of 2 pg/L, with a reporting level (RL) of 5 Ng/L and a method detection level (MDL) of 0.3 pg/L. Sample results above the MDL, but below the RL, are only estimates (i.e. j-flagged), and are not quantified. If the Caltest result were the only result, the 2 pg/L estimated concentration would exceed the 1.8 pg/L CTR criterion, and reasonable potential could be found if the Regional Water Board found that the estimated value was a reliable indicator that the bis(2- ehtylhexly) phthalate was present at or above 1.8 ug/L. However, as shown in the record, Montgomery Watson's analysis of the duplicate sample was an actual measured concentration of only 1.4 pg/L, with a reporting level of 0.6 pg/L. There is a higher degree of confidence in the measurement from Montgomery Watson, because the concentration was above the reporting level. Bis(2-ethylhexyl) phthalate is particularly subject to false positive results. Based on monitoring data provided by other dischargers, the Regional Water Board has found that sampling and lab contamination for bis(2-ethylhexyl) phthalate is common and has resulted in many false- positive results for this constituent. Samples can be easily contaminated with bis(2-ethylhexyl) phthalate when plastic piping and containers are used or by the use of rubber gloves. Given this evidence, the Regional Water Board can and should use its discretion when evaluating reasonable potential for this constituent. Therefore, the permit concluded that sufficient information did not exist to determine reasonable potential. The Regional Water Board is allowed this discretion by the SIP in Section 1.2, which states, "The RWQCB shall have discretion to consider if any data are inappropriate or insufficient for use in implementing this Policy. Instances where such consideration is warranted include, but are not limited to, the following: evidence that a sample has been erroneously reported or is not representative of effluent or ambient receiving water quality; questionable quality control/quality assurance practices; and varying seasonal conditions." (Emphasis added). The adopted Order appropriately required monthly monitoring for bis(2-ethylhexyl) phthalate using clean techniques to ensure that valid, representative data would be available to conduct a reasonable potential analysis. We request that the proposed State Board Order be revised to delete all references to bis(2-ethylhexyl) phthalate. If you have any questions, please contact Kenneth Landau at (916) 464-4726 or kl u@waterboards.ca.gov. MELA C. CREEDON Executive Officer