Updated assessment of occupational safety and health hazards of climate change

Workers, particularly outdoor workers, are among the populations most disproportionately affected by climate-related hazards. However, scientific research and control actions to comprehensively address these hazards are notably absent. To assess this absence, a seven-category framework was developed in 2009 to characterize the scientific literature published from 1988-2008. Using this framework, a second assessment examined the literature published through 2014, and the current one examines literature from 2014-2021. The objectives were to present literature that updates the framework and related topics and increases awareness of the role of climate change in occupational safety and health. In general, there is substantial literature on worker hazards related to ambient temperatures, biological hazards, and extreme weather but less on air pollution, ultraviolet radiation, industrial transitions, and the built environment. There is growing literature on mental health and health equity issues related to climate change, but much more research is needed. The socioeconomic impacts of climate change also require more research. This study illustrates that workers are experiencing increased morbidity and mortality related to climate change. In all areas of climate-related worker risk, including geoengineering, research is needed on the causality and prevalence of hazards, along with surveillance to identify, and interventions for hazard prevention and control.

Trichloroethylene, trichloroacetic acid, and dichloroacetic acid: do they affect fetal rat heart development?

Trichloroethylene (TCE), trichloroacetic acid (TCA), and dichloroacetic acid (DCA) are commonly found as groundwater contaminants in many regions of the United States. Cardiac birth defects in children have been associated with TCE, and laboratory studies with rodents report an increased incidence of fetal cardiac malformations resulting from maternal exposures to TCE, TCA, and DCA. The objective of this study was to orally treat pregnant CDR(CD) Sprague-Dawley rats with large bolus doses of either TCE (500 mg/kg), TCA (300 mg/kg), or DCA (300 mg/kg) once per day on days 6 through 15 of gestation to determine the effectiveness of these materials to induce cardiac defects in the fetus. All-trans retinoic acid (RA) dissolved in soybean oil was used as a positive control. Soybean oil is commonly used as a dosing vehicle for RA teratology studies and was also used in this study as a dosing vehicle for TCE. Water was used as the dosing vehicle for TCA and DCA. Fetal hearts were examined on gestation day (GD) 21 by an initial in situ, cardiovascular stereomicroscope examination, and then followed by a microscopic dissection and examination of the formalin-fixed heart. The doses selected for TCA and DCA resulted in a modest decrease in maternal weight gain during gestation (3% to 8%). The fetal weights on GD 21 in the TCA and DCA treatment groups were decreased 8% and 9%, respectively, compared to the water control group and 21% in the RA treatment group compared to soybean oil control group. The heart malformation incidence for fetuses from the TCE-, TCA-, and DCA-treated dams did not differ from control values on a per fetus or per litter basis. The rate of heart malformations, on a per fetus basis, ranged from 3% to 5% for TCE, TCA, and DCA treatment groups compared to 6.5% and 2.9% for soybean oil and water control groups. The RA treatment group was significantly higher with 33% of the fetuses displaying heart defects. For TCE, TCA, and DCA treatment groups 42% to 60% of the litters contained at least one fetus with a heart malformation, compared to 52% and 37% of the litters in the soybean oil and water control groups. For the RA treatment group, 11 of 12 litters contained at least one fetus with a heart malformation. Further research is needed to quantify the spontaneous rates of heart defects for vehicle control rats and to explain the disparity between findings in the present study and other reported findings on the fetal cardiac teratogenicity of TCE, TCA, and DCA.

Repeated exposure of rats to JP-4 vapor induces changes in neurobehavioral capacity and 5-HT/5-HIAA levels

Thirty-two Sprague-Dawley rats were exposed for 6 h/d for 14 consecutive days to JP-4 jet fuel vapor (2 mg/L) or room air control conditions. Following a 14- or 60-d recovery period, rats completed a battery of 8 tests selected from the Navy Neurobehavioral Toxicity Assessment Battery (NTAB) to evaluate changes in performance capacity. Exposure to JP-4 vapor resulted in significant changes in neurobehavioral capacity on several tests that varied as a function of the duration of the recovery period. Rats were evaluated for major neurotransmitter and metabolite levels in five brain regions and in the blood serum. Levels of 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) were shown to be significantly elevated in several brain regions as well as in the blood serum in the vapor-exposed groups. Results of the rat study are compared to previously reported neurobehavioral evaluations of European manufacturing personnel exposed chronically to jet fuel vapor.