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• INFORMATION SHEET -3- CITY OF LATHROP AND METROPOLITAN LIFE INSURANCE COMPANY WASTEWATER TREATMENT FACILITY NO. 1 (CROSSROADS) SAN JOAQUIN COUNTY service to the State far outweigh the environmental impact damage of a community that would otherwise be reliant on numerous concentrated individual wastewater systems. Economic prosperity of local communities is of maximum benefit to the people of California, and therefore sufficient reason to accommodate increases in wastewater discharge provided terms of reasonable degradation are defined and met. The proposed Order authorizes some degradation consistent with the maximum benefit to the people of the State. Groundwater monitoring at the site to date has not been sufficient to establish the most appropriate groundwater limits. In addition, certain aspects of waste treatment and control practices have not been and are unlikely to be justified as representative of best practicable treatment and control (BPTC). Reasonable time is necessary to gather specific information about the WWTF and the site to make informed, appropriate, long-term decisions. This proposed Order, therefore, establishes interim receiving water limitations to assure protection of the beneficial uses of groundwater of the State pending the completion of certain tasks and provides time schedules to complete specified tasks. The Discharger is expected to identify, implement, and adhere to BPTC as individual practices are reviewed and upgraded in this process. During this period, degradation may occur from certain constituents,but can never exceed water quality objectives (or background water quality should it exceed objectives) or cause nuisance. Water quality objectives define the least stringent limits that could apply as water quality limitations for groundwater at this location, except where background quality unaffected by the discharge already exceeds the objective. The values below reflect water quality objectives that must be met to maintain specific beneficial uses of groundwater. Unless natural background for a constituent proves higher,the groundwater quality limit established in proposed Order is the most stringent of the values listed for the listed constituents. Constituent Units Value Beneficial Use Criteria or Justification Ammonia mg/L 0.5 MUNTaste and Odor 2 Boron mg/1 0.7 AGR Boron Sensitivity Chloride mg/L 106 AGR' dhloride sensitivity on certain crops irrigated via sprinklers" 142 AGR' Chloride sensitivity on certain crops" 250 MUN ' Recommended Secondary MCL 5 500 MUN ' Upper Secondary MCL 5 Iron mg/L 0.3 MUN ' Secondary MCL c Manganese mg/L 0.05 MUN ' Secondary MCL c Nitrate as N mg/L 10 MUN ' Primary MCL 7 Nitrite as N mg/L 1 MUN ' Primary MCL 7 Sodium mg/L 69 AGR' Sodium sensitivity on certain crops° Total Dissolved Solids mg/L 4508 AGR 3 Salt sensitivity Total Coliform Organisms MPN/100 ml 2.2 MUN ' Basin Plan 500 MUN ' Recommended Secondary MCL 5 1,000 MUN' Recommended Upper MCL 5 Total Trihalomethanes µg/L 100 MUN' MCL' PH pH Units 6.5 to MUN' Secondary MCL 9 8.5