California ground water contamination

CohenDB. 1986. Ground water contamination by toxic substances, California Assessment. Pollutant Investigations Branch, State Water Resources Control Board, Sacramento, CA American Chemical Society. 

Jackson, R. E., 1999, Anticipating Ground-Water Contamination by New Technologies and Chemicals The Case of Chlorinated Solvents in California Environmental Engineering Geoscience, Fall, Vol. V, No. 3, pp. 331-338. 

Oliveira DP, Sitar N. 1985. Ground water contamination from underground solvent storage tanks, Santa Clara, California. In Proceedings of the Fifth National Symposium on Aquifer Restoration and Ground Water Monitoring, 691- 708. 

S. Amter and B. Ross, Was Contamination of Southern California Ground-water by Chlorinated Solvents Foreseen Environmental Forensics, vol. 2, pp. 179-184 (2001). 

The Toxicological and Epidemiological Effects of Pesticide Contamination in California Ground Water... 

A review of California information on ground water contamination indicates that while the causes are site specific, most incidents occurred because of three interrelated problems ... 

Formulation, storage, and poor disposal practices have resulted in a number of pesticide ground water contamination incidents in California 2). 

DBCP has been found In ground water In Hawaii, California, Arizona, South Carolina, and Maryland (5-7,19,77-79). Typical positives are 0.02-20 ppb. Areas with the highest frequency of positives and the highest well concentrations are the San Joaquin Valley In California and the region southwest of Phoenix, Arizona. The Hawaii contamination has occurred despite several hundred feet of overburden between the basal aquifer and the surface. One set of California soil core results show that ppb amounts of DBCP has leached about 15 m through the unsaturated zone ( ), whereas DBCP was not detected In another set of California soil cores sampled as deep as 10 m and five years after the last application (80). The latter results can possibly be explained by rapid movement of DBCP down the soil profile to depths greater than 10 m. 

At the Sierra Army Depot in Herlong, California, groundwater had been contaminated by trinitrotoluene (TNT) and trichloroethylene (TCE). The 28-acre plume of contaminated ground-water was located about 70 ft underground. The U.S. Army evaluated the cost difference between conventional pump-and-treat systems, ultraviolet (UV) oxidation, granular activated carbon (GAC) filters, and MNA. The active treatments were estimated to cost between 6 and 10 million while MNA costs were estimated to be approximately 1 million (D17451Q). 

In a groundwater contamination study of 28 of California s 58 counties that evaluated over 50 pesticides (from both point and nonpoint sources), diazinon was detected in 12 samples (Cohen 1986). Diazinon is included as an analyte of interest in the EPA Pesticides in Ground Water Database (EPA 1989a) and was... 

During the past decade, the State Water Resources Control Board, California s environmental protection agency for water quality, has learned that we have not done enough to prevent the growing problem of toxic chemical contamination of our ground water. 

I ppb. California has spent over 10 million in Fresno County alone to rehabilitate DBCP-contaminated ground water supplies. 

DBCP appears to persist in soils for decades with a half-lifeof over a century (60. At one California site, DBCP was found to persist in top soil for nearly a decade after a single application (J). This study conducted in 1980 in the Parlier area showed DBCP contamination to a depth of 30 feet throughout the soil profile. The highest concentrations of DBCP were found in the clay and silt layers. DBCP findings in soil and ground water coincided with areas of high DBCP use. This has led State Board staff to conclude that past agricultural use is the most likely source of this widespread contamination. 

---