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INFORMATION SHEET ORDER NO.R5-2004-0028 13 INFORMATION SHEET ORDER NO.R5-2004-0028 14 CITY OF MANTECA,CITY OF LATHROP AND DUTRA FARMS CITY OF MANTECA,CITY OF LATHROP AND DUTRA FARMS WASTEWATER QUALITY CONTROL FACILITY WASTEWATER QUALITY CONTROL FACILITY SAN JOAQUIN COUNTY SAN JOAQUIN COUNTY for aluminum expressed as total recoverable are 750 ug/1(1-hour average)and 87 ug/1(4-day average), calculating Effluent Limitations for MBAS(see Table 6). Because of the observed foaming at the and are appropriate to implement the narrative toxicity objective. Since both the receiving water and outfall,no dilution is available for MBAS. An Effluent Limitation for MBAS is included in this Order the effluent exceed USEPA's ambient water quality criteria and the secondary MCL,no dilution can be and is based on the Basin Plan water quality objectives for chemical constituents,floating material,and granted. The effluent has the reasonable potential to cause or contribute to an in-stream excursion tastes and odors. above water quality objectives for aluminum. Therefore,this Order includes an effluent limitation for Aluminum of 71 ug/1 as a 30-day average and 143 ug/1 as the daily maximum. The monitoring data are 9.7 Molybdenum included in Table 3 and the effluent limitation calculations are included in Table 6. The recommended agricultural water quality goal for molybdenum,that would implement the narrative 9.4 Iron "Chemical Constituent"objective,is 10 ug/1 based on Water Quality for Agriculture,Food and Agriculture Organization of the United Nations—Irrigation and Drainage Paper No.29,Rev.1(R.S. Iron concentrations in the effluent ranged from 170-730 ug/1 while background concentrations in the Ayers and D.W.Westcot,Rome,1985). Molybdenum was not monitored in the effluent or in the San Joaquin River ranged from 780-2800 ug/1 based on results from 12 samples collected between receiving waters. Because of the uncertainty associated with the lack of monitoring,additional studies January 2002 and December 2002. The Basin Plan chemical constituents objective includes a of this constituent are warranted to more thoroughly evaluate reasonable potential for this constituent receiving water objective in Table III-1 for iron of 300 ug/l in the Delta,and the secondary MCL for to exceed criteria. MRP No.R5-2004-0028 specifies monitoring for this pollutant. If the monitoring iron of 300 ug/l. Both the receiving water and the effluent exceed the Basin Plan numeric objective shows a reasonable potential to cause or contribute to an exceedance of a water quality objective,this and the secondary MCL. Water quality based effluent limitations are included in this Order based on Order may be reopened for addition of appropriate effluent limitations. the Basin Plan chemical constituents objective. The data are included in Table 3 and the effluent limitation calculations in Table 6. 9.8 Carbofuran 9.5 Manganese The Basin Plan contains a narrative objective for toxicity that prohibits concentrations of toxic substances that could produce detrimental physiological responses in humans. Public Health Goals Manganese concentrations in the effluent ranged from 13-120 ug/1 while background concentrations in published by OEHHA provide a measure of an amount of a toxic substance that,if exceeded could the San Joaquin River ranged from 82-220 ug/1 based on results from I 1 samples collected between contribute to toxicity in humans who consume the water for municipal or domestic supply(MUN). January 2002 and December 2002. The Basin Plan chemical constituents objective includes a MUN is a designated beneficial use of the receiving water. Carbofuran was detected in the effluent receiving water objective in Table III-1 for manganese of 50 ug/1 in the Delta,and the secondary MCL and receiving water at concentrations greater than the Public Health Goalof 1.7 ug/l. Because the data for manganese of 50 ug/l. Both the receiving water and the effluent exceed the Basin Plan numeric were greater than the method detection limit but less than the laboratory's reporting(quantitation) objective and the secondary MCL. Water quality-based effluent limitations are included in this Order limit,the data were flagged as"detected but not quantified". Additional monitoring is required. If the based on the Basin Plan chemical constituents objective. The data is included in Table 3 and the monitoring shows a reasonable potential to cause or contribute to an exceedance of a water quality effluent limitation calculations in Table 6. objective,this Order may be reopened to consider incorporation of appropriate effluent limitations. 9.6 Methylene blue active substances(MBAS) 9.9 Nitrate and Nitrite The effluent contains MBAS at levels that may cause or contribute to exceedances in the receiving Nitrate and nitrite are known to cause adverse health effects in humans. The Basin Plan's chemical waters of water quality objectives in the Basin Plan. The Basin Plan includes the"Chemical constituents water quality objective prohibits chemical constituents in concentrations that exceed Constituents"objective that incorporates state MCLS that applies to waters designated MUN. MUN is drinking water Maximum Contaminant Levels(MCLS)published in Title 22 of the California Code of a designated beneficial use of the San Joaquin River. The Secondary MCL Consumer Acceptance Regulations or that adversely affect beneficial uses. Municipal and domestic water supply is a Limit is 500 ug/l for foaming agents(MBAS). The Basin Plan also includes water quality objectives beneficial use of the San Joaquin River. The California Department of Health Services(DHS)has that water not contain floating material or taste-or odor-producing substances in concentrations that adopted Primary Maximum Contaminant Levels(MCLS)for the protection of human health for nitrite causes nuisance or adversely affect beneficial uses. The Basin Plan identifies non-contact water and nitrate that are equal to I mg/1 and 10 mg/l(measured as nitrogen),respectively. Title 22 CCR, recreation,which includes aesthetic enjoyment,as a beneficial use of the San Joaquin River. MBAS Table 64431-A,also includes a primary MCL of 10,000 ug/1 for the sum of nitrate and nitrite, concentrations in excess of the Secondary MCL produce aesthetically undesirable froth,taste,and measured as nitrogen. The discharge from the WQCF has a reasonable potential to cause or contribute odor. Foam has been observed on the surface of the discharge plume from the WQCF. MBAS was to an in-stream excursion above water quality standards for nitrite and nitrate because of the detected in an effluent sample collected 13 June 2002 at a concentration of 1,800 ug/l. The maximum nitrification and denitrification processes. Effluent limits for nitrite and nitrate are based on the MCLS. observed upstream receiving water MBAS concentration is less than 20 ug/1. These data were used in Effluent Limitations for nitrite and nitrate are included in this Order to assure the treatment process