Usually, elevated levels of metal contaminants in the water can be traced to point-source discharges from industrial sources. Not so in Hawai`i, however. With rare exceptions (such as at Schofield Barracks), metal contaminants are extremely low in the point-source discharges permitted under the Clean Water Act. But that is not to say that the coastal waters are free from contamination by heavy metals. Far from it. Although point-source discharges may be relatively metal-free, non-point source runoff is another story.
Some insight into this problem was provided recently in a request from Chevron USA to the Environmental Protection Agency, seeking modifications in its National Pollutant Discharge Elimination System permit for a “land treatment facility,” or landfarm, for chemicals generated at Chevron’s Barber’s Point refinery. Chevron was requesting, among other things, permission to drop the arsenic-monitoring requirement. Here is its explanation:
“Arsenic has historically been detected in the groundwater at the Chevron Hawaiian refinery. However, Chevron does not believe groundwater concentrations of arsenic to be a result of activities at the refinery or releases from hazardous waste or solid waste management units… Concentrations of arsenic in the landfarm soils and background soils are similar to those found on the island.
“Possible sources of the arsenic detected in the groundwater include: historical use of sodium arsenate as a herbicide by sugar cane and pineapple growers as well as the former Nahiku Rubber Company; erosion of treated lumber; and spills/contamination from the Honolulu Wood Treating Company located in the Campbell Industrial Park. Personal communications with Dr. Hilton of the Hawaiian Sugar Planters Association (June 1991) has confirmed the use of sodium arsenate by sugar cane and pineapple growers periodically from 1913 until the start of World War II. Dr. Hilton also recalls the extensive use of arsenic as a herbicide by the former Nahiku Rubber Company. The rubber company’s use of arsenic prompted the sugar cane and pineapple growers to test the herbicide. The start of WWII ended the extensive use of arsenic as it became a strategic metal and its availability was limited.
“Research recently conducted by the School of Public Health at the University of Hawai`i has documented the presence of arsenic in beach waters and eatable algae (E.N. Galvez, 1990). Ms. Galvez reports concentrations up to 57 ppm arsenic (dry weight) in some species of algae. Seawater was also tested for arsenic and mean concentrations ranged from 627 ppm [parts per billion] at Ewa Beach to 772 ppb at Ka`alawai Beach. Seawater concentrations at the O`ahu beaches are an order of magnitude higher than the MCL [maximum contaminant level] of 50 ppb for arsenic [established by the EPA].
“Dr. Barbara Siegul with the School of Public Health hypothesizes that the source of arsenic in the waters surrounding O`ahu is a result of deterioration of treated lumber. Treated wood is used extensively in Hawai`i due to problems associated with termites and ants on the island.
“In lieu [sic] of the above information, Chevron does not believe that arsenic is an appropriate indicator parameter for the groundwater detection monitoring program at the landfarm.”
Recently the General Accounting Office, the investigative arm of Congress, reported that by the Environmental Protection Office’s own reckoning, non-point source pollution posed a greater health threat than pollution that comes from a single point (such as a sewer outfall or other well-defined source). But Hawai`i has virtually no data on background levels of arsenic or other toxic metals in coastal waters.
In the next year, this may change. Last April the Department of Health signed a contract with Battelle Memorial Institute, Pacific Northwest Laboratories, for a survey of metals in low concentrations in seawater and underlying sediment. When the results come in, the problem of contamination will remain, but at least the state will have a baseline against which to measure future changes in water quality.
Volume 2, Number 5 November 1991
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