What’s in the Paint?
words by susan preston / photograph by pete byron
enato Martins of Kearny, NJ, paints bridges for a living — big bridges that span highways and waterways — the 59th Street Bridge in Manhattan, the George Washington Bridge crossing the Hudson River. A carpenter who exchanged his hammer for a paint brush 24 years ago, he loves his job. But he also knows it might be harming his health because of his constant exposure to chemical solvents in paint and lead in the bridge beams.
So he didn’t hesitate when asked to participate in the studies Nancy Fiedler, PhD, is conducting to determine if these exposures are causing health problems in bridge painters and carpenters. “Personally, I think the paint is worse than the lead,” Martins says. “I had a friend, also a bridge painter, who died in 2003 from lung cancer and I believe the chemicals in the paint were responsible.”
Fiedler, a clinical psychologist who developed an interest in neurotoxicants many years ago, initiated the solvent exposure study four years ago because “despite extensive literature evaluating the chronic effects of exposure to solvent mixtures, solvent encephalopathy remains controversial.” Encephalopathy is a disease of the brain. “The literature is plagued by inadequate characterization of exposure and control of confounding variables, but it does suggest that working memory, which relies on frontal brain structures, is the cognitive function most sensitive to chronic solvent exposures,” she explains.
Since construction painters are among those workers most highly exposed to a mix of organic solvents, Fiedler approached three unions to recruit volunteers for both this study and the lead exposure study. The participants are from District Council 21, International Union of Painters and Allied Trades, Philadelphia; Local 806, Structural Steel and Bridge Painters of Greater New York International Union of Painters and Allied Trades, New York City; and Carpenters Local 1006, Milltown, NJ.
The focus of the solvent exposure study is to compare cognitive performance and neural activation differences between painters with at least a decade of experience on the job to drywaller/tapers and carpenters with minimal exposure to neurotoxicants but matched in terms of demographics and work history profiles. Each group has 150 participants, all of whom completed a physical exam, a visual contrast sensitivity evaluation, cognitive function tests, and the Cambridge Neuropsychological Test Automated Battery to assess attention, working and visual memory. To test neural activation, the solvent-exposed and controls have also undergone a Blood Oxygen Level Dependent function magnetic resonance imaging exam while completing tests of working memory.
“We are seeking to determine whether the workers with chronic exposure to solvents have lost the ability to process information efficiently and whether they are using different neural structures to compensate for inefficient or poor performance. Finally, we’re looking for genetic polymorphisms that are associated with solvent metabolism to determine if differences in metabolism confer increased risk for health effects,” Fiedler says.
The lead exposure study was undertaken by Fiedler three years ago because “lead continues to pose health risks for those sectors of the population in which exposure is highest, particularly individuals of lower socioeconomic status and workers in the construction trades.” She noted that in addition to the effects on cognitive function, chronic lead exposure is associated with hypertension and cardiovascular disease.
Prior to beginning this study, the UMDNJ team reviewed studies done by Deborah Cory-Slechta, PhD, of the University of Rochester School of Medicine and Dentistry. Her research indicated that in laboratory animals with chronic exposure to lead during gestation and lactation, the hypothalamic pituitary adrenal axis function was permanently altered in their offspring, revealed by increased basal corticosterone
levels. “If the same changes occur in humans exposed to lead over a long period of time, vulnerability to disease could result,” she says. This study has enrolled 55 healthy individuals exposed to lead and 55 unexposed healthy individuals, all between the ages of 30 and 50.
The exposure is determined by Cd K X-ray fluorescence of the tibia to assess the bone lead burden. Participants perform the Trier Social Stress Test, comprised of public speaking and math tests. Blood samples are taken throughout the battery of tests to measure ACTH, cortisol, epinephrine, norepinephine and dopamine. Blood pressure is taken throughout the testing. Fiedler is also analyzing genetic
polymorphisms associated with lead metabolism to determine if these factors confer increased risk.
Martins, who is from Brazil and whose family comes from Portugal, has taken time he doesn’t really have because of work and family responsibilities, to be part of these research studies. Why? “It’s not just about my health,” he says proudly. “We might protect the health of many people all around the world with this knowledge.”