TNRCC tightens requirements for perchlorate levels

Waco Tribune-Herald, Richard Smith
Published October 13, 2001

A chemical found at a former rocket plant in McGregor must be at lower levels in drinking water than previously allowed, state environmental officials said. The Texas Natural Resource Conservation Commission earlier this month set new interim drinking water levels for perchlorate at 4 parts per billion. That is the same perchlorate limit that had been recommended in a report released this summer by the Environmental Working Group, a research organization. The new drinking water limit replaces the former Texas standard of 22 parts per billion. "The decision is good news for the thousands of Texans whose drinking water supplies are contaminated with this potent thyroid toxin," said Bill Walker, California director of the environmental group. "Both TNRCC and the U.S. EPA, which recently set the same cleanup level for a severely contaminated site in California, have now recognized that even very low levels of perchlorate pose health risks, especially for pregnant or nursing women, their unborn babies and infants." Perchlorate became a focus of cleanup efforts at the former Naval Weapons Industrial Reserve Plant in McGregor after it was discovered in Harris Creek in 1998. Harris Creek flows into the South Bosque River. Perchlorate was a main ingredient used in making rockets at the plant. All health risks from the substance in drinking water are not completely known. However, it has been associated with thyroid problems. Thyroid hormones are crucial to proper development of many of the body's organ systems. There have been detections of perchlorate believed to have come from the McGregor plant in several streams in both the Bosque and Leon watershed. However, no perchlorate has been detected in any of the area's drinking water, said Jim Beltz, a Navy spokesman. The state's adopting a lower perchlorate limit means that if the TNRCC issues a permanent permit for the Navy to discharge water at McGregor, perchlorate concentrations in drinking water downstream could be no more than 4 parts per billion. Dick Lewis, a TNRCC spokesman, said the EPA previously had a range of perchlorate limits from which states could choose going from 4 parts per billion to 32 parts per billion. He said the EPA told the agency that, in light of scientific studies, they might consider tightening the drinking water standard for perchlorate at McGregor. The EPA has since changed its range of drinking water limits to between 4 parts per billion and 18 parts per billion, said Dave Bary, a spokesman for the EPA regional office in Dallas. What number is used as a drinking water limit depends on the particular site that has perchlorate contamination. Bary said the limit can be different for each site. The number chosen depends on factors such as the site's proximity to large numbers of people and how the water supply might potentially be affected. Environmental officials say readings of about 90,000 parts per billion of perchlorate have been found in groundwater on certain areas of the McGregor plant site. Navy contractors have been working on methods to treat the contaminated water. Those contractors also have been taking water samples from streams in both the Bosque and Leon watershed. The TNRCC issued emergency permits during the spring so that treated contaminated groundwater held in tanks on the site could be released. The Navy declined to seek a more permanent discharge permit in 1999. Cities whose drinking water comes from lakes on the Bosque and Leon rivers had opposed the permit and had sought a hearing on the application before a judge. The Navy's spokesman said the Navy has received nothing in writing from the TNRCC on the levels being lowered. But, he said, the Navy would abide by environmental regulations. "Our position is we'll meet or exceed the levels the TNRCC proposes," Beltz said. Representatives of cities in both the Bosque and Leon watersheds called the state's lowering of the perchlorate limit a positive step. "What this tells me is the TNRCC looked at it further and decided to go the conservative way on this," said Ricky Garrett, city of Waco utilities director. "We had felt 22 parts per billion was kind of high." Harker Heights Mayor Mary Gauer said it was "about time" the state lowered the limit. "Going down to 4 parts per billion would suit me just fine," she said. Studies are ongoing in both the Bosque and Leon watersheds that evaluate potential effects perchlorate might have on humans and the environment. The two-year, $8 million study is being undertaken by the U.S. Army Corps of Engineers along with entities such as the Brazos River Authority and with researchers from Texas Tech University. Corps spokesman Ron Ruffennach said the study began earlier this year. Officials from these entities will brief the public on the study's progress during meetings Monday at Waco High School and Tuesday at the Frank W. Mayborn Civic and Convention Center in Temple.