Correspondence Comment on “Widespread Presence of Naturally Occurring Perchlorate in High Plains of Texas and New Mexico” The first sentence of the paper by Rajagopalan and co-workers (1) refers to “the discovery of perchlorate (ClO4-) as a groundwater contaminant in California in 1997.” This is not correct. The statute that established California Regional Water Pollution Control Boards (RWPCB, now called Regional Water Quality Control Boards) in 1949 authorized the boards to impose requirements on dischargers of wastes so as to protect groundwater resources that were being used by others (2). Requirements for the Aerojet General rocket plant in Sacramento, California were established in 1952 (3). The RWPCB ordered that process wastes containing potassium perchlorate, ammonium perchlorate, and various other compounds “shall not be discharged in a manner which will permit their entry into either the ground water or the waters of the American River.” At the request of the RWPCB (4), the California Department of Water Resources sampled wells near the Aerojet plant as part of a newly initiated state-wide program of groundwater quality monitoring. In its section on Sacramento County, the initial report of the results of this program (5) stated the following: The waste discharge from a large industry in the eastern portion of the county poses a potential threat to ground water quality. The wastes include solutions of potassium perchlorate (KClO4) and ammonium perchlorate (NH4ClO4) and tests for these constituents are included in the analyses. Analyses of samples collected from well No. 9N/ 7E-28B1 which supplies the above industry, showed an increase in the perchlorate ion from 2 ppm in November, 1955, to 18 ppm in May, 1956. Perchlorate was detected in several wells monitored by the program in 1957 (6). A short article summarizing a national survey of groundwater contamination was published in the Journal of the American Water Works Association in 1957. This article (7) reported the following: About 14 miles east of Sacramento, manufacturing wastes were discharged into gold-dredge tailing pits. These wastes were in the form of potassium
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and ammonium perchlorate, constituents not found in natural ground waters. As perchlorates are toxic to plants in concentrations of 1-2 ppm, they have been used as weedicides. The wastes, having concentrations of 3,500-5,000 ppm of perchlorate, appear to have affected an area of several miles. A renewed groundwater investigation of the Aerojet Sacramento plant was undertaken in 1979. A 1985 conference paper (8) describing this investigation reported that “Although NDMA was discovered in groundwaters in Sectors A and B and perchlorate in Sectors E, F and G, the investigations indicated that volatile organics were the principal chemicals of concern...” This historical error has no bearing on the research reported in the remainder of the paper by Rajagopalan et al. The research reported here was supported in part by the law firm of Engstrom, Lipscomb, and Lack.
Literature Cited (1) Rajagopalan, S.; Anderson, T. A.; Fahlquist, L.; Rainwater, K. A.; Ridley, M.; Jackson, W. A. Widespread presence of naturally occurring perchlorate in high plains of Texas and New Mexico. Environ. Sci. Technol. 2006, 40, 3156-3162. (2) Ross, B.; Amter, S. Deregulation, chemical waste, and ground water: A 1949 debate. Ambix 2002, 49, 52-67. (3) Central Valley Regional Water Quality Control Board. Resolution No. 127, May 15, 1952. (4) Edmonston, E. D. California State Engineer, Memorandum to J. S. Gorlinski, January 10, 1955. (5) California Department of Water Resources. Quality of ground waters in California 1955-1956; Bulletin No. 66; Sacramento, CA, June 1958. (6) California Department of Water Resources. Quality of ground waters in California 1957; Bulletin No. 66; Sacramento, CA, April 1960. (7) Miller, L. M. Underground waste disposal and control. J. Am. Water Works Assoc. 1957, 49, 1334-1342. (8) Thompson, C. H.; Phinney, S. L.; McLaren, F. R. Aerojet: A regional site program s Problem definition; In Proceedings Hazardous Wastes and Environmental Emergencies, May 1416, 1985, Cincinnati, OH; pp 115-118.
Steven Amter* and Benjamin Ross Disposal Safety Incorporated Washington, DC 20036 ES061262P
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