Reso 1996-006 to 010 - Laserfiche WebLink

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FINDING: As described in the Draft SEIR, there would be no adverse effects of potentially present explosive compounds. STATEMENT OF FACTS: Considering the past land use of the project area, the possible presence of explosive compounds in soil is a concern. Nitrostarch, quantified as nitrocellulose (a similar compound), used as a propellant, was found in Area 2 in all 8 samples for which it was tested, in concentrations from 20 mg/kg to 6,400 mg/kg (equivalent to a total explosive concentration of 0.002% to 0.64%). Nitroglycerin was found in one sample of the 19 tested for this analyte. On the basis of research conducted by U.S. Army Corps of Engineers Environmental Center (USAEC) on the ignitability of nitrocellulose in soil at the U.S. Army Badger Ammunitions Depot in Wisconsin, the concentrations of nitrocellulose and nitroglycerin in soils present at the project site do not pose an explosion hazard. A review of HLA's investigations on the Roberts Landing site was recently conducted by an independent consultant, Tetra Tech Incorporated. Tetra Tech, in their report, notes that the USAEC considers soils with total explosive concentrations about 14% to be potentially dangerous. However, explosive concentrations measured on the project site are an order of magnitude below this level. Consequently, Tetra Tech concluded that the concentrations of nitrocellulose and nitroglycerin measured in soil on the site "do not appear to pose a threat to human health or the environment." The Tetra Tech report also suggested that additional sampling for explosive compounds might be appropriate, particularly in areas where major channel excavation would occur as part of the wetland enhancement plan implementation. However, such additional sampling does not appear warranted, given that the entire sampling protocol for the project site was developed in close consultation with and, under the approval of, both DTSC and RWQCB. In addition major channel excavation of Roberts Landing Slough immediately downstream of the project site was carried out recently as part of the City's Shoreline Marshlands Enhancement project without any incident relating to potential presence of explosive compounds. C.3 POTENTIAL IMPACT: Exposure to electric and magnetic fields generated by power lines in the transmission corridor could pose direct health threats to certain future residents in the project area. FINDING: Changes or alterations have been required in, or incorporated into, the project that further avoid or substantially lessen the potential significant environmental effect. STATEMENT OF FACTS: No definite conclusion has been reached in the scientific community regarding the health effects of exposure to high -voltage transmission lines. Currently, no State or Federal regulations exist regarding electromagnetic radiation from powerlines in proximity to residential areas. At 200 feet, a typical 115 kilovolt transmission line would emit 1.9 milligauss magnetic fields and 0.01 kilovolts/meter electric fields (APA, 1991). Measurements taken at the site indicate that at the closest homesite in Phase 113, about 175 feet, the milligauss 8