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By Haidee V. Eugenio

SAIPAN, CNMI (Marianas Variety, Nov. 3) – Toxic chemicals including lead, chromium, arsenic and benzene have been found in the soil and groundwater of certain areas of Chalan Piao and Fina Sisu, according to a July 22, 2004 report contracted by the U.S. Army Corps of Engineers.

Local environmental agencies, however, never released copies of this report, which also stated that the low chemical concentrations "do not warrant active remediation."

The other known Saipan areas contaminated with military chemicals are Tanapag and I-Denni on Capitol Hill.

The Army Corps contracted Wil-Chee Planning Inc., which subcontracted portions of the project work to Clayton Group Services to investigate the extent and type of contamination found in Chalan Piao and Fina Sisu, which were once part of the U.S. military’s Kobler Naval Supply Center.

According to a 1947 U.S. Navy inspection report, the center had five 10,000-barrel aboveground storage tanks and four 1,000-barrel aboveground storage tanks that leaked up to 6 inches of fuel over a 16-day period.

No documentation for fuel recovery was found.

The U.S. Environmental Protection Agency’s preliminary remediation goal for lead is 400 mg/kg, but five samples from three tank sites at the former Kobler Naval Supply Center showed near-surface lead contamination ranging from 480 mg/kg to 2,900 mg/kg.

The Clayton Group Services report, however, said that lead-impacted soil "appears to be the result of the lead-based paint and primer that were used to originally coat the tanks."

Near-surface chromium contamination was also present in concentrations greater than the EPA preliminary remediation goal of 270 mg/kg.

One sample had total metal chromium concentration of 1,680 mg/kg.

EPA’s preliminary remediation goal for arsenic is 22 mg/kg, but samples showed that the levels of arsenic in the soil ranged from 22 mg/kg to 27 mg/kg.

Background sampling and analysis previously conducted in 1999 identified background concentrations of arsenic as high as 33.6 mg/kg.

Also detected in soil samples were barium, mercury, selenium, cadmium, benzene and other volatile organic compounds but they were in concentrations less than the EPA’s preliminary remediation goal.

Groundwater samples collected identified a benzene concentration of 0.0079 mg/L, which is greater than the maximum contaminant level of 0.005 mg/L.

Chromium was detected at concentrations ranging from 0.0035 mg/L to 0.12 mg/L — exceeding the maximum contaminant level of 0.10 mg/L.

Total metal-lead in groundwater was detected at levels from 0.54 mg/L to 0.32 mg/L, which is greater than the maximum contaminant level of 0.015 mg/L.

Total metal-mercury was detected at concentrations of up to 0.006 mg/L, which is greater than the maximum contaminant level of 0.002 mg/L.

Also detected in groundwater samples but below the maximum contaminant level were barium and arsenic.

Clayton Group Services said the step-drawdown and vapor extraction test results indicate that the extraction of groundwater and soil vapor to address remediation of groundwater contamination is "possible."

However, it said that the low chemical concentrations do not warrant active remediation.

"Since the source of contamination is no longer present and the chemical movement is limited, a more appropriate remedial action appears to be natural attenuation," the report added.

It said that the highest benzene concentration from the groundwater wells of 0.0079 mg/L is "slightly" above the maximum contaminant level of 0.005 mg/L.

"These low levels indicate that natural attenuation has occurred at the site and that chemical degradation is likely to continue, thereby reducing benzene concentrations to levels below the maximum contaminant level," the report said.

The Kobler Naval Supply Center is located approximately 1.25 miles northwest of Saipan’s international airport, consisting of two separate but adjoining areas.

The first area covers about 64 acres in Fina Sisu, containing nine 10,000-barrel aboveground storage tanks and was referred to as the Chalan Kanoa tank farm.

The second area is the 32-acre Chalan Piao/As Perdido site containing nine 1,000-barrel aboveground storage tanks and was referred to as the Old South Tank Farm.

November 3, 2005

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