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j I • REMEDIAL ALTERNATIVES - 3 - Chemicals detected and levels of concern, 1905 N. Broadway, Stockton Chemical Background* Maximum Level of Reference Concern? concentration concentration concern Nitrate-N 5-42 mg/I 57 mg/I 10 mg/1 CA MCL Yes Total Kjeldahl nitrogen ND-6 mg/I 26.6 mg/l 0.5 mg/l as taste & odor Yes ammonia Ammonia-N 0.2 mg/1 17.7 mg/1 0.5 mg/1 taste & odor Yes 1,2,3'-trichloropropane ND 66 µg/1 5 µg/1 USEPA Health Yes Advisory (HA) 1,2-dichloropropane 0.59 µg/I 160 µg/I 0.56 µg/l CalEPA Yes Cancer Potency Factor (CPF) 2,4-DB ND 1.4 µg/1 none none no bromochloromethane ND 3.1 µg/l 90 gg/1 USEPA HA no bromodichloromethane " ND 3.3 µg/1 0.27 µg/I CaIEPA CPF Yes %chloroform ND-1.1 µg/I 23 µg/l 1.1 µg/1 CaIEPA CPF Yes dibromochloromethane ND 65 µg/1 0.37 µg/I CalEPA CPF Yes DBCP ND 6.5 µg/I 0.005 µg/1 CalEPA CPF Yes dichloroprop ND 2 µg/1 none none no dinoseb ND 21 µg/1 7 µg/I CA MCL Yes methylene chloride ND 0.8 µg/1 2.5 µg/l CalEPA CPF no (dichloromethane) tetrachloroethane 2 It g/1 1.8 µgl1 0.69 It g/1 CaIEPA CPF no (see (PCE) bkgrd cone) * The concentration found in background monitoring wells MW-3 and MW-10 As the table shows, there are ten chemicals which have been detected at concentrations greater than the regulatory level of concern. The evaluation of remedial alternatives needs to focus on all the chemicals, not just on 1,2-DCP. 4.2 Physical and Chemical Properties The document states that the chemical concentration in the vapor phase will increase with an increase in temperature. This has been shown to occur at the site when 1,2-DCP has volatilized when stored in an open 500-gallon poly tank. Therefore, another remedial alternative may be to pump the water, heat it, and volatile the 1,2-DCP. Depending on the pounds volatilized, it could then either be vented to air or captured in a carbon drum.