At right: Barrel and crab from the Farallon Island Region
"There is intense public and media interest in this issue, and we need to have the best information available when we respond to inquiries or participate in discussions on the issue of radioactive waste dumped near the Farallones."
--Barbara Boxer; United States Congress (D-California). June, 1990
More than 47,800 drums and other containers of low-level radioactive waste were dumped onto the ocean floor west of San Francisco between 1946 and 1970; many of these are in the Gulf of the Farallones National Marine Sanctuary.
Although the drums were to be dumped at three specific sites, there are no drums at the exact location of the site covered by this study.
Preliminary maps show the location of many drums, but only 15 percent of the radioactive waste dump area has been mapped.
This information can be used to sample around the drums to determine if the radioactive material is leaking or otherwise affecting the environment.
Between 1946 and 1970, approximately 47,800 large barrels and other containers of radioactive waste were dumped in the ocean west of San Francisco. The containers were to be dumped at three designated sites, but they a litter sea floor area of at least 1,400 km2 known as the Farallon Island Radioactive Waste Dump.
The exact location of the containers and the potential hazard the containers pose to the environment are unknown.
The USGS developed computer techniques and contracted with private industry to enhance sidescan- sonar data--collected in cooperation with the Gulf of the Farallones National Marine Sanctuary--to detect objects as small as 55-gallon steel barrels while conducting regional sidescan-sonar surveys. Locations of probable 55-gallon containers derived from the enhanced sidescan sonar images were plotted on a map covering a 125-km2 area.
The U.S. Navy, the USGS, and the Gulf of the Farallones National Marine Sanctuary pooled their expertise and resources to verify the new computer enhancement techniques developed for detecting targets on sidescan sonar images the size of 55-gallon barrels.The acoustic intepretations were verified using the USN DSV (Deep Submergence Vehicle) Sea Cliff and the unmanned Advanced Tethered Vehicle (ATV).
Barrels and other physical features were found without fail where image enhancement had indicated they would be found.
Without maps as guides to probable barrel sites, previous attempts to locate the barrels using submersibles were like trying to find a needle in a haystack. In contrast, using the new acoustic maps to drive from one barrel site to the next, each Sea Cliff and ATV dive verified the predicted absence or presence of barrels.
The interagency cooperation among the USN, USGS, and Gulf of the Farallones National Marine Sanctuary has provided the technological, scientific, and practical expertise to develop a cost-effective and time-efficient method to locate the barrels of radioactive waste. This method can be used to locate containers of hazardous waste over a regional scale in other ocean areas such as Boston Harbor and the Kara Sea in the Arctic.