In a study that may have far-reaching implications for people living beside hazardous chemical waste sites, two scientists today reported that infants born to mothers living immediately adjacent to a New Jersey landfill at the height of its activity had substantially lower birthweights and as much as twice the risk of being born preterm.
Epidemiologists Michael Berry, currently with the New Jersey Department of Health and Senior Services, and Frank Bove of the federal Agency for Toxic Substances and Disease Registry, which partly financed the study, reported their findings in Environmental Health Perspectives, the monthly* journal of the National Institute of Environmental Health Sciences.
The report is based on data collected from residents of four municipalities that border the Lipari landfill, a 15-acre site located in Gloucester County that was used for the dumping of household and industrial wastes from 1958 until 1971. The landfill was once rated number one on the Environmental Protection Agency's priority list, a national ranking system for hazardous waste sites based on the health risks they pose to surrounding populations.
The researchers divided the infants' mothers into "exposure categories" based on the distance of their residences from the landfill. Those who lived within a one-kilometer radius of the landfill (slightly more than six-tenths of a mile) were placed in the "exposed" category; those who lived beyond this boundary constituted the "unexposed" group. To assess the effects of chemical exposure on those who lived immediately downwind from the landfill, the investigators conducted separate analyses on the residents located directly adjacent to the site.
The researchers found that the average birthweight of infants born in the "exposed" area was 65 grams (more than two ounces) less than that of the infants born in the "unexposed" group. Then they discovered the birthweight differences were concentrated in the residential area nearest the landfill -- these infants were, on average, 141 grams (more than four ounces) lighter than their "unexposed" counterparts. They also found that infants born in this residential area had twice the risk of being born preterm (gestational age less than 37 weeks) compared to the unexposed controls.
These effects occurred only among those infants born between 1971 and 1975, the period corresponding to the heaviest runoff of hazardous materials and the greatest likelihood of chemical exposure to nearby residents. Neither the infants born before, when dumping had not yet reached its peak, nor those these born afterward, when dumping had ended and remedial cleanup had begun, were similarly affected.
"The magnitude of this effect is about as bad as the birthweight reduction that is associated with cigarette smoking during pregnancy," said Berry, the lead investigator. "These findings are quite significant given the fact that low-birthweight and preterm babies have a lower chance of survival and a greater risk of developing post-birth problems than those born within the normal range."
Developed as a joint venture between the New Jersey Department of Health and community leaders and activists, the study was designed to address the concerns of nearby residents to toxic chemicals emanating from the hazardous waste landfill. Infant birthweights were selected for study because they are an objective indicator of infant health, and because the information could be readily obtained from birth certificates. The researchers took into account potential risk factors such as maternal age and education, previous pregnancies and prenatal care, but other factors, such as maternal health, and cigarette and alcohol consumption during pregnancy, were not included on the birth certificate and could not be evaluated.
First excavated as a source of sand and gravel, the Lipari landfill was later back-filled with municipal waste, household wastes, liquid and solid chemical wastes, and other industrial wastes. These included cleaning solvents, resins, paint and paint thinners, ester press cakes, phenol wastes and amine wastes. Operation of the landfill ended in 1971 because of nearby residents' complaints regarding odors, respiratory problems, headaches, nausea, and dying vegetation.
In 1985, a remedial investigation of the Lipari landfill conducted by EPA revealed hazardous levels of a chemical called bis chloroethyl ether (BCEE). Other chemicals identified by the investigators included benzene, toluene, methylene chloride, dichloroethane, formaldehyde, phenol, chromium, nickel, mercury, lead, selenium, arsenic, and silver.
The researchers said, "The real public health threat to residents near the contamination was likely due to volatile organic compounds -- chemicals such as benzene and xylene that evaporate into the air and thus expose people nearby." Both have been associated with low birthweight in some animal studies.
Other studies have linked low birthweight offspring to men working with auto body solvents and working mothers exposed to polychlorinated biphenyls (PCBs). Low birthweight (an average decrease of 50 grams) was also shown in the newborns of homeowners in the Love Canal, N.Y., neighborhood.
*This is the August issue of the journal, which was delayed by publishing difficulties until today.