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Although nitrate is a naturally-occurring compound necessary for plant growth, it can <br /> cause health problems when present at high levels in drinking water. The most <br /> common health effect of nitrates in water is methemoglobinemia, or blue baby <br /> syndrome, which results in reduced oxygen supply to vital tissues. Pregnant women <br /> and certain others can also develop methemoglobinemia. Symptoms include a bluish <br /> color of the skin, as well as headache, dizziness, weakness, and difficulty breathing. <br /> Ingestion of high levels of nitrates over time can also lead to gastric problems. <br /> DBCP is a nematocide and soil fumigant for vegetables and grapes. It is known to <br /> cause male reproductive effects and is classified as a probable human carcinogen. <br /> Most domestic use of DBCP was discontinued in 1977 through 1979. The US EPA set <br /> the MCL at 0.2 parts per billion (ppb, equivalent to ug/L) because it believes that given <br /> present technology and resources, this is the lowest level to which water systems can <br /> reasonably be required to remove this contaminant should it occur in drinking water. <br /> The Maximum Contaminant Level Goal (MCLG) for DBCP is zero. <br /> Soil Profile and Geoloq�c lnformation <br /> The Site is depicted on the Preliminary geologic map of showing Quaternary deposits of <br /> the Lodi quadrangle, California (Marchand and Atwater, 1979). The Site is depicted <br /> within a map unit of the Modesto formation upper member described as "arkosic <br /> alluvium forming Mokelumne River alluvial fan; chiefly sand, becoming finer-grained <br /> toward fan toe; probably glacial outwash" (Plate 8). <br /> The surface and near surface soils located at the Site are reported by the USDA Web <br /> Soil Survey to be composed of Guard clay loam (Plate 9) (USDA, 2020). The table <br /> below presents some selected properties of this soil: <br /> Table 1. Selected Properties of On-Site Soils (USDA, 1992) <br /> Soil Name Depth Unified Soil Salinity Soil Perme- Septic tank <br /> and Map /cm Reaction ability absorption <br /> Symbol (in) Classification mmhos pH (in/hr) fields <br /> Guard clay 0-15 Clay loam; CL <2 7.9-8.4 0.2-0.6 Severe: <br /> loam, 15-72 Clay loam, sandy clay <2 7.9-8.4 0.06-0.2 peres slowly <br /> drained, 0- loam; SC, CL <br /> 2% slopes, <br /> 169 <br /> Note: The table descriptions do not necessarily reflect site-specific soil properties. See description of the map unit for <br /> composition and behavior characteristics of the map unit. <br /> LOGE 20-15 Page 5 <br />