SBCT Final EIS - Govsupport.us

Chapter 3 ⎯ Affected Environmentthe investigation conducted at SBMR, the investigation was not intended to be a comprehensive studyof the distribution of contaminants on the ranges, but was only intended to support the description ofcurrent conditions and to provide evidence of the effects of past training activities on surface soils andsurface water. The results of the study are summarized below.Semi-volatile Organics. Similar to the samples collected at SBMR, metals, explosives, and SVOCs(phthalate esters and polynuclear aromatic hydrocarbons [PAHs]) were detected. The phthalate estersare plasticizers and are ubiquitous in the environment, although they may have been present becauseof plastic parts in munitions. PAHs, produced by combustion of heavy organic compounds includingwood, oils, and tars, are also common in the environment at low concentrations. None of the semivolatileorganics detected exceeded industrial soil PRGs.Explosives. The sampling detected six explosives including TNT, 2,4-dinitrotoluene (DNT) (a degradationproduct of TNT), RDX, HMX, nitroglycerin, and perchlorate. With the exception of 2,4-DNTand perchlorate, these are the same compounds that were detected in samples from SBMR, suggestingthat the effects of past training activities on surface soils and surface water are relatively consistentbetween military installations. Four of the 46 samples had detectable concentrations of TNT, but noneof the samples exceeded the industrial soil PRG. The detections were found in three samples from theRange 9 Demo Area and in one sample from Range 5. Three samples contained 2,4-DNT at concentrationswell below the industrial soil PRG. Perchlorate was detected in one sample, from firing pointFP309 in the northwest corner of Training Area 8, at concentrations below the industrial soil PRG.Concentrations of RDX exceeded its industrial PRG in five samples.Metals. Metals occur naturally in Hawaiian soils; however, human activities may also contribute tothe background levels of metals in soils. Even in natural conditions, metals concentrations are expectedto vary among different areas. This variation was observed in the metals concentrations of thesoils on PTA. One reason for this phenomenon could be that the heterogeneous lavas on which thethin, poorly developed soils formed contained different compositions of metals due to varying ages ofthe flows, and the soils have not had much time to be mixed or redeposited (USAG-HI 2004).When metals concentrations are significantly different from the typical background range of concentrations,then it is more likely that human sources contributed to the metals concentrations. Amongthe metals that were analyzed in the samples, the most abundant metals in basalt minerals are aluminum,barium, chromium, iron, nickel, and zinc. Other metals would generally be expected to be presentat lower concentrations. Except for iron, none of these metals were detected at concentrationsabove the residential soil PRGs. Iron did not exceed the industrial PRG in any samples collected fromPTA. Chromium, nickel, and zinc were detected in one sample from Range 11 at much higher concentrationsthan in the other samples, indicating possible contribution by human sources, but the concentrationswere still less than the industrial soil PRGs. Zinc was also detected in a few samples fromRange 5 at much higher concentrations than in other samples from that range, but the concentrationswere below the industrial soil PRGs.Most other less abundant metals were detected at concentrations below their respective industrial soilPRGs. The highest concentrations were generally detected in a single sample from Range 11, or insamples from Ranges 9 or 10. Exceptions to this were apparently random distributions of higher concentrationsof beryllium and selenium, including background samples from near the Range Controloffice. The highest lead concentrations, two of which exceeded the industrial soil PRG, were detectedin samples from Ranges 9, 10, and 11.Based on the results of the 2002 investigation, it appears that both elevated metals concentrations anddetectable explosives concentrations were generally found in the impact areas of Ranges 5, 9, 10, andFebruary 2008 3–16 2/25th SBCT Final EIS