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Although nitrate is a naturally -occurring compound necessary for plant growth, it can cause health problems when present at high levels in drinking water. The most common health effect of nitrates in water is methemoglobinemia, or blue baby syndrome, which results in reduced oxygen supply to vital tissues. Pregnant women and certain others can also develop methemoglobinemia. Symptoms include a bluish color of the skin, as well as headache, dizziness, weakness, and difficulty breathing. Ingestion of high levels of nitrates over time can also lead to gastric problems. DBCP is a nematocide and soil fumigant for vegetables and grapes. It is known to cause male reproductive effects and is classified as a probable human carcinogen. Most domestic use of DBCP was discontinued in 1977 through 1979. The US EPA set the MCL at 0.2 parts per billion (ppb, equivalent to µg/L) because it believes that given present technology and resources, this is the lowest level to which water systems can reasonably be required to remove this contaminant should it occur in drinking water. The Maximum Contaminant Level Goal (MCLG) for DBCP is zero. Soil Profile and Geoloaic Information The Site is depicted on the Geologic Map of the San Francisco -San Jose Quadrangle, California (Wagner et al., 1991). The Site is depicted within a map unit of the Modesto formation (Plate 8). The surface and near surface soils located at the Site are reported by the USDA Web Soil Survey to be composed of Galt clay (Plate 9) (USDA, 2022). The table below presents some selected properties of this soil: Table 1. Selected Properties of On -Site Soils (USDA, 1992) Soil Name Depth Unified Soil Salinity Soil Perme- Septic tank and Map (in) Classification mmhos/cm Reaction ability absorption Symbol pH (in/hr) fields Galt clay, 0-25 Clay; CL, CH <2 6.6-7.3 0.06-0.2 Severe: 0-2% slopes, 25-34 Clay, silty clay, CL, <2 6.6-8.4 0.06-0.2 cemented 160 CH --- --- --- pan, peres 34-60 Cemented slowly Note: The table descriptions do not necessarily reflect site-specific soil properties. See description of the map unit for composition and behavior characteristics of the map unit. Soil Borings On May 2, 2022, Live Oak excavated shallow and deep borings near the proposed septic disposal area of the new house on the Site for the purpose of conducting a percolation test. The borings were four inches in diameter, 3.39 to 4.48 feet deep, and were excavated by hand auger (Table 2). The location of the borings is indicated on Plate 10. LOGE 2226 Page 5