User:Dwin22/Alark Hard Chrome

Alark Hard Chrome in Riverside, California is currently listed on the National Priorities List as a superfund site for soil and groundwater contamination.

History
From 1971 to 1985 Alark Hard Chrome operated as a metal plating shop. Employees there had dipped bumpers and other car parts into vats of chrome, some of which spilled and contaminated the ground. Soil contamination was first identified at the site in 1982 when the Riverside County Health Department discovered chromium and other metals present as a result of spills, drips and discharges from a reservoir on the premises where plating solutions were disposed. In 1985, when the plant failed to comply with violation notifications from the California Department of Toxic Substance Control (DTSC), the Riverside District Attorney ordered for the plant to be closed permanently and all plating equipment and indoor storage tanks were removed from the facilities. The following year, the potentially responsible parties at Alark began removing soil from the site. This was unauthorized and as a result, DTSC halted such operations and took over the site in 1990. The facility was placed on the Environmental Protection Agency’s Superfund National Priorities List in 2000 indicating that it is considered one of the most hazardous waste sites. The site is currently closed and additional sampling is required before it can be fully characterized. Once analysis is completed the Environmental Protection Agency will begin exploring possible options for remediation of the soil and groundwater contamination.

Who is Involved
This is a fund-lead site. United States Environmental Protection Agency (EPA) is the lead agency.

On-site Contamination
The main contaminants found at the site were hexavalent chromium, total chromium, cadmium, lead, nickel, cyanide, and TCE. Subsurface soil tests for VOCs showed non-detectable, or very low, levels. The following chemicals were also used on-site: ammonia, cyanide, sodium cyanide, cadmium cyanide, chromic acid, sulfuric acid, sodium hydroxide, nickel chloride, nickel sulfate and methyl ethyl ketone.

Soil and water samples have been collected from the site on various occasions since 1990. According to the California Department of Health Services' Public Health Assessment, some contaminants were found in concentrations lower than the threshold at which adverse health effects can influence nearby communities, while others exceeded this range. In 2000 surface soil samples testing showed levels of hexavalent chromium at only 38 parts per billion (ppb), which is below the health comparison value for adverse health effects. Surface water was also tested. In this test total chromium concentrations exceed 10,000 ppb, which absolutely exceeds California's standard of 50 ppb. Cadmium was also detected 134 ppb, greater than healthy standard of 5 ppb. These results indicate that the surface water contaminated by the Alark Hard Chrome site is certainly unsuitable for drinking or any other human uses. Groundwater samples were also taken from a monitoring well in the years 1991, 1995 and 2001. Total chromium values from these three samples range from 1,700 to 10,200 ppb, with 5,300 to 40,000 ppb of that from hexavalent chromium alone. These values also greatly exceed those for acceptable drinking water.

Investigation and Cleanup Activities
The site has been closed off. EPA has completed an initial remedial investigation that attempted to defined the full extent of contamination. EPA will begin looking at possible ways to clean up the soil and groundwater contamination. The site was placed on the EPA’s Superfund list that prioritizes cleanup at the worst toxic waste sites nationwide. Monitoring wells were drilled in 2007 and 2011.


 * In 2000, the federal government took over the site because the chromium had seeped into the groundwater near the Santa Ana River, a drinking-water source. On August 2, 2012, The U.S. Environmental Protection Agency tested wells and sampled groundwater in downtown Riverside around a closed chrome-plating operation where toxic hexavalent chromium seeped into the aquifer. Officials found that the contamination has not affected drinking-water wells.

Once the latest round of testing is finished in October, the EPA will develop a plan for cleaning up the soil and groundwater, according to an EPA notice to residents in the area.

Timeline

 * 1971- Present

1971 – Metal plating shop established in Riverside

1982 – Riverside county health department inspected the site and discovered soil contamination

1985 – The site was shut down by Riverside County Health Department

1986 – performed an unauthorized excavation action that was halted by the California Department of Toxic Substances Control (DTSC)

1990-91 – DTSC conducted subsurface soil investigation

1994 – DTSC excavated 1,207.73 yards of contaminated soil

1992-95 – DTSC installed groundwater-monitoring wells

2001 – EPA conducted groundwater sampling and the results were consistent with the groundwater investigation conducted by DTSC in 1995

2007 – EPA completed the fieldwork for the remedial investigation with the installation of one additional monitoring well that defined the groundwater contaminant plume southeast of the site / EPA began a Treatability Study to evaluate the effectiveness of in-situ treatment of hexavalent chromium

2009 – Treatability Study completed, final Treatability Study Report issued

2011 – chromium-6 in Riverside Public Utilities’ water ranged from 1.9 parts per billion to 2.7 parts per billion.

2012 – The U.S. Environmental Protection Agency tested wells and sampled groundwater in downtown Riverside around a closed chrome-plating operation where toxic hexavalent chromium seeped into the aquifer

2013 – EPA will begin the Feasibility Study (FS) after the completion of a data gap analysis and fieldwork to fill in information not collected in the RI and Treatability Study work