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INFORMATION SHEET ORDER NO.R5-2004-0028 21 INFORMATION SHEET ORDER NO.R5-2004-0028 22
<br /> CITY OF MANTECA,CITY OF LATHROP AND DUTRA FARMS CITY OF MANTECA,CITY OF LATHROP AND DUTRA FARMS
<br /> WASTEWATER QUALITY CONTROL FACILITY WASTEWATER QUALITY CONTROL FACILITY
<br /> SAN JOAQUIN COUNTY SAN JOAQUIN COUNTY
<br /> less than 10 values,the maximum effluent concentration and a 3.11 multiplier(from Table 5-2 of the not protective of actual bioaccumulation conditions in the River. Health advisories by the Department
<br /> TSD)provides the estimated maximum levels. The calculations of the allowed dilution are shown in of Health Services remain in effect for human consumption offish in the Delta,including the San
<br /> Table 12 which:(1)summarizes the monitoring data for the human carcinogens that have reasonable Joaquin River at Manteca,due to excessive concentrations of mercury in fish tissue. These current
<br /> potential to exceed human carcinogen criteria;(2)summarizes the statistics used in calculating the warnings and available fish tissue data confirm that there is currently no assimilative capacity in the
<br /> estimated maximum concentration;and,(3)determines the amount of dilution that would be required Delta for mercury.
<br /> to meet the applicable human-carcinogen criteria. Final effluent limitations are calculated and
<br /> summarized in Table 13. Group A organo-chlorine pesticides,which include lindane,endrin aldehyde and DDT are also on the
<br /> 303(d)listing. The Basin Plan sets forth a water quality objective that requires that organo-chlorine
<br /> 11.2.3 Ability to Meet Effluent Limitations and Interim Requirements pesticides not be present in the water column in detectable concentrations. The SIP designates
<br /> acceptable minimum laboratory detection levels for lindane,endrin aldehyde and DDT at 0.02 ug/l,
<br /> Based on historical effluent data,the WQCF can meet the effluent limitations for 0.01 ug/1 and 0.01 ug/l,respectively. The organo-chlorine pesticide effluent concentrations and
<br /> dibromochloromethane,bromodichloromethane,2,4,6-trichlorophenol,and bis(2-ethylhexyl)phthalate. corresponding reporting levels are at or below the SIP minimum levels and meet the Basin Plan
<br /> Additionally,because the plant will install a UV disinfection system by 1 February 2009,the THM objective. Based on these considerations,effluent limitations for Group A pesticides are not required
<br /> constituents are expected to decrease significantly. in this Order.
<br /> Section 1.4.2.2.11 of the SIP requires,among other things,that when a mixing zone/dilution credit is Effluent samples collected from January 2002 to December 2002 contained mercury concentrations
<br /> granted,the permit must specify the point in the receiving water where the applicable ranging from 0.013 ug/l to 0.028 ug/l. Receiving water monitoring for mercury over the same period
<br /> criteria/objectives must be met. The Discharger has not performed such an analysis over a variety of provided results ranging from 0.0036 ug/1 to 0.0093 ug/l. Table 14 summarizes the mercury data and
<br /> flow conditions. However,considering the long-term averaging period for human carcinogens,the statistics associated with the mercury results.
<br /> infrequency of critical conditions and worst-case effluent concentrations,and the fact that there are no
<br /> drinking water intakes for numerous miles down-or up-stream of the discharge,the Regional Board The effluent and receiving water have also been monitored for Group A pesticides and PCBs on four
<br /> finds the lack of a detailed mixing zone study is not significant enough to postpone the imposition of occasions during 2002. Dioxin(2,3,7,8-TCDD)was monitored twice during 2002. These constituents
<br /> final effluent limitations for dibromochloromethane,bromodichloromethane,2,4,6-trichlorophenol and were not detected in the effluent or receiving water samples. Detection limits for DDT,PCB and the
<br /> his(2-ethyhexyl)phthalate. 2,3,7,8-TCDD were not adequate to determine compliance with the water quality criteria,therefore
<br /> continued monitoring is required in this Order. Table 10 summarizes these results.
<br /> 11.2.4 Receiving Water Monitoring for Human Carcinogen Priority Pollutants
<br /> 11.3.1 Interim Requirements-Bioaccumulative Priority Pollutants
<br /> Receiving water monitoring of human carcinogens is required to provide assurance that water quality
<br /> criteria are being met downstream of the discharge and that the beneficial use of municipal supply is The SIP recommends that the Regional Board consider whether the mass loading of bioaccumulative
<br /> being protected. Although a mixing zone analysis has not been performed to delineate the specific pollutants should be limited in the interim to"representative current levels"pending development of
<br /> boundaries of the mixing zone for human carcinogens,the samples collected at the existing R-1 and R- applicable water quality standards or TMDL allocation. The intent is,at a minimum,to prevent further
<br /> 4 receiving water monitoring locations should provide adequate information to demonstrate impairment while a TMDL for a particular bioaccumulative constituent is being developed. Any
<br /> compliance with water quality criteria. increase in loading of mercury to an already impaired water body would further degrade water quality.
<br /> 11.3 Bioaccumulatives An interim effluent mass limitation for mercury has been determined using the WQCF design flow of
<br /> 8.11 mgd and the maximum observed concentration. The data and calculation,as summarized in Table
<br /> Based on information submitted by the Discharger,the Regional Board concludes that the discharge 14,provided an interim yearly mass limitation for mercury of 0.69 pounds/year(as total recoverable).
<br /> contains mercury. The Delta waterways are listed in accordance with Clean Water Act Section 303(d)
<br /> as impaired for mercury based on bioaccumulation of this pollutant in fish tissue. The CTR contains To track the Discharger's compliance with the interim mass limitation,the Discharger is required to
<br /> criteria for mercury. The CTR criteria,however,do not address bioaccumulation in the river. The calculate a 12-month consecutive running average of the mass loading for mercury. Starting on the
<br /> WQCF effluent contains detectable levels of mercury below CTR priority pollutant criteria. However, 12`"month after adoption of this permit,and for every month thereafter,the total mass pollutant
<br /> the bioaccumulation rates in fish tissue used to calculate the CTR water quality criteria are based only loading for the previous twelve months will be reported in the monthly discharge monitoring reports
<br /> on a laboratory derived bioconcentration factor that considers organism uptake from water only and and compared against the interim mass limitation calculated in the previous section. In addition to the
<br /> does not consider the contribution from the organism's food source. Therefore,the CTR criteria are
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