Some of the toxic contamination at Alameda Point is not the result of naval operations.

The soil beneath the runways became contaminated with polycyclic aromatic hydrocarbons (PAHs) before it ever became part of Alameda Point. The fill material used for creating this land mass was dredged from the Oakland Estuary primarily between 1936 and 1941 by means of a pumping system. It was contaminated by a coal gasification plant, which operated in Oakland about 100 years ago that disposed of waste into the waterway.

The Navy recently began cleaning up contaminated soil at five hot spots in the airplane runway. Cleanup Site 33, the area commonly referred to as the wildlife refuge, encompasses the southern end of the main north-south runway and adjacent tarmac, and is near the least tern nesting site and a wetland area.

Some of the sediment contamination may also have originated at the Pacific Coast Oil Refinery that operated on the West End in 1879 and later moved to Richmond.

The potential health risk from PAHs, normally through ingestion of dust, has been part of cleanup evaluations for over a decade. The Navy and regulatory agencies agreed to the EPA's residential soil standard in 2001.

PAH soil sampling began in 2002 at 300 locations throughout Alameda Point; Site 33, produced more than 1,200 samples. The 500-plus acre wildlife refuge parcel had 79 soil borings that produced 316 samples. Samples from five boreholes produced samples that exceeded residential use standards.

A 2008 report recommended additional testing at Site 33 that was done in 2010, leading to the current cleanup work at the five hot spot areas.

Over the past 22 years, more than 28 environmental studies have been conducted on the "refuge parcel," looking at everything from volatile organic compounds, petroleum byproducts, PAHs, pesticides, PCBs, dioxins, explosives, metals, and radium. The Navy analyzed surface sediment, soil, surface water, underground water, manhole sediment and animal and plant tissue samples. Aerial photographs were also reviewed.

Talks between the Navy and US Fish & Wildlife Service for establishing a national wildlife refuge reached an impasse a decade ago, before many of these studies were completed, due to Fish & Wildlife's concerns about liability for unforeseen cleanup expenses.

Today, the refuge parcel is slated to be transferred to the US Department of Veterans Affairs. Only about 40 acres of the refuge will be needed for their national cemetery and clinic if plans are approved to move most of the project northward onto the city's Northwest Territories parcel.

The Navy will present an update on Site 33's soil cleanup at the next Restoration Advisory Board meeting 6:30 p.m., Thursday, Nov. 8 at 950 West Mall Square, Community Conference Room at rear of building.

Richard Bangert writes the online Alameda Point Environmental Report.