High levels of vinyl chloride monomer have been detected in water systems in some central and Southern states. But state and pipe industry officials say there is no cause for alarm, because in many cases the VCM was due to unusual circumstances.
Following reports in Kansas last year that 12 water systems tested positive for high VCM levels in 1992, officials in Missouri, Iowa, Texas, Arkansas, Nebraska, Oklahoma and New Mexico opted to test their rural water systems.
Texas detected the largest amount of VCM in one of its rural water systems at 20 parts per billion. The legal limit for VCM in water is 2 ppb, Patrick Shaughnessy, a spokesman for the Texas Natural Resources Conservation Commission, said in a March 25 telephone interview.
Only 18 of the state's 7,000 water systems participated. Of those, VCM levels of 2.5 ppb and 2.7 ppb were detected in two old PVC lines, he said.
During retesting of those sites, the commission found VCM at one site of 20 ppb, while the other site showed no signs of the chemical, Shaughnessy said.
He blames the high VCM level on the water line being long and only 11/2 inches in diameter. The water probably was stagnant, he said, as the line served only one house located on a country road and the pipe was old.
Iowa also found high VCM amounts in several systems but would not conclude PVC pipe was the cause. An extensive study of all 20 of Iowa's rural water districts showed significant amounts of VCM in three water lines, said Roy Ney, lead engineer of water supply at the Iowa Department of Natural Resources. The tests detected VCM levels of 1.6 ppb, 5.8 ppb and 15 ppb.
High levels of VCM in a water supply typically are the result of several factors, said David Eckstein, deputy executive director of Uni-Bell PVC Pipe Association.
First, a small pipe must have been installed before 1977, it must be in a rural area at the end of a water line, in a warm climate, and the water would have had to be idle for at least several days.
That was the case in Iowa, where the line showing VCM levels of 15 ppb was not in use because the one house it would have served never was hooked up, Ney said.
``It's surprising it wasn't higher than 15,'' he added.
VCM was not detected anywhere else in that line.
To make sure the water did not get back into the system, the water district flushed and capped the end of that line. The state discovered similar circumstances in the other cases where it had found VCM. Retesting on those lines showed no signs of VCM, Ney said. However, the state will continue testing.
``We feel that there were causes for those elevated levels. We don't feel we're in the pipe-replacement mode,'' he said.
Arkansas' highest VCM detection level was 0.47 ppb, significantly lower than the legal limit of 2 ppb, said Harold Seifert, director of the engineering division at the Arkansas Department of Natural Resources. Of 81 systems tested, eight showed signs of VCM. Those eight were retested last fall and VCM was detected in only two water lines in southern Arkansas, he said.
The department will resume testing and focus primarily on those two lines to assure the public there is not a problem.
``There's the possibility of a public reaction to a problem that might not even exist,'' Seifert said.
Test results in Missouri showed at least one water district had VCM levels above 2 ppb. State officials could not be reached for comment.
Testing in New Mexico and Nebraska showed no signs of VCM. Oklahoma sampled several water systems but the shelf life of the samples expired before testing was completed, Uni-Bell's Eckstein said.
According to the federal Environmental Protection Agency, the water must show an average VCM level above 2 ppb following four quarterly tests during one year to be considered a threat.
Uni-Bell and the Washington-based Vinyl Institute are working with states to continue testing PVC pipes installed before 1977.
If a significant problem should be found, the groups will replace the PVC pipe free of charge and provide affected families with bottled water until it is resolved, Eckstein said.