Apartment residents' and day care workers' exposures to tetrachloroethylene and deficits in visual contrast sensitivity.

Abstract

Tetrachloroethylene (also called perchloroethylene, or perc), a volatile organic compound, has been the predominant solvent used by the dry-cleaning industry for many years. The U.S. Environmental Protection Agency (EPA) classified perc as a hazardous air pollutant because of its potential adverse impact on human health. Several occupational studies have indicated that chronic, airborne perc exposure adversely affects neurobehavioral functions in workers, particularly visual color discrimination and tasks dependent on rapid visual-information processing. A 1995 study by Altmann and colleagues extended these findings, indicating that environmental perc exposure at a mean level of 4,980 microg/m(3) (median=1,360 microg/m(3)) alters neurobehavioral functions in residents living near dry-cleaning facilities. Although the U.S. EPA has not yet set a reference concentration guideline level for environmental exposure to airborne perc, the New York State Department of Health set an air quality guideline of 100 microg/m(3). In the current residential study, we investigated the potential for perc exposure and neurologic effects, using a battery of visual-system function tests, among healthy members of six families living in two apartment buildings in New York City that contained dry-cleaning facilities on the ground floors. In addition, a day care investigation assessed the potential for perc exposure and effects among workers at a day care center located in the same one-story building as a dry-cleaning facility. Results from the residential study showed a mean exposure level of 778 microg/m(3) perc in indoor air for a mean of 5.8 years, and that perc levels in breath, blood, and urine were 1-2 orders of magnitude in excess of background values. Group-mean visual contrast sensitivity (VCS), a measure of the ability to detect visual patterns, was significantly reduced in the 17 exposed study participants relative to unexposed matched-control participants. The groups did not differ in visual acuity, suggesting that the VCS deficit was of neurologic origin. Healthy workers in the day care investigation were chronically exposed to airborne perc at a mean of 2,150 microg/m(3) for a mean of 4.0 years. Again, group-mean VCS, measured 6 weeks after exposure cessation, was significantly reduced in the nine exposed workers relative to matched controls, and the groups did not differ significantly in visual acuity. These results suggested that chronic, environmental exposure to airborne perc adversely affects neurobehavioral function in healthy individuals. Further research is needed to assess the susceptibility of the young and elderly to perc-induced effects, to determine whether persistent solvent-induced VCS deficits are a risk factor for the development of neurologic disease, and to identify the no observable adverse effect level for chronic, environmental, perc exposure in humans.

Letter to the editor: “Review of the epidemiologic literature on residential exposure to perchloroethylene” by John A. Bukowski

“…We found and report no consistent effect of residential perc exposure on adult VCS at the highest levels of indoor air perc found (up to about 700 µg/m 3 (NYS DOH, 2010). This is not inconsistent with other residential studies of adults that found either no neurobehavioral effects or effects only at higher levels of exposure than found in our study (Altmann et al, 1995;Schreiber et al, 2002;Storm & Mazor, 2004).…”

“…However, selection bias was minimized by our recruitment methods. Earlier research had shown that perc exposures might be elevated in some, but not all, residential buildings where a dry cleaner using perc was colocated, and that vision in adults might be harmed by such exposures (Altmann et al, 1995;Schreiber et al, 2002). Other research suggests that children might be more affected by exposure to environmental contaminants, including perc, than adults (Needham & Sexton, 2000;Stein et al, 2002;Schwenk et al, 2003).…”

Target Organ Metabolism, Toxicity, and Mechanisms of Trichloroethylene and Perchloroethylene: Key Similarities, Differences, and Data Gaps

“…For PCE, neurotoxicity is the most sensitive outcome of exposure in humans, where toxicity is observed even at low-exposure concentrations. For instance, perturbations in visual contrast sensitivity have been observed with chronic exposure to as little as 0.3 ppm PCE (Schreiber et al, 2002;New York State Department of Health, 2010), whereas effects in other organs (e.g., liver or kidney) are not observed until airborne concentrations of PCE are at least two to three orders-of-magnitude higher (US EPA, 2011a). A very recent study reported an increased risk of epilepsy in humans exposed to PCE through contaminated public water supplies during gestation or early childhood (Aschengrau et al, 2015).…”

Richtwerte für Tetrachlorethen in der Innenraumluft

“…Aufgrund der Lipophilie wurde der höchste Gewebe-Blut-Verteilungskoeffizient in vitro erwartungsgemäß für Fettgewebe (125) ermittelt im Vergleich zu Niere, Leber, Muskel (5-6) [17]. Tetrachlorethen konnte in humaner Muttermilch nachgewiesen werden [17][18][19].…”