Neural Tube Defects, Environment, and Occupation
Only weak associations between environmental pollution and neural tube defects are reported in the literature, and specific studies that relate parental occupation to these defects are scarce. Blatter et al. (p. 140) summarize the available data on neural tube defects and their relation to pollution and occupation. If broader categories such as central nervous defects are included, then both maternal and paternal occupation seem to be associated with these malformations. Because the data are inconsistent and sparse, more studies are needed before relevant measures for prevention can be recommended.
Environmental Problems in China and Russia
As China takes steps toward participating in a global economy and Russia moves toward a democratic system of government, both countries face rampant environmental problems resulting from years of denial and neglect (p. 154). China's most serious environmental problem is air pollution: chemical companies and the burning of coal for heat have contributed to respiratory disease being the leading cause of death in China. Russia's environmental woes include soil and water pollution from industrial and nuclear wastes as well as air pollution. At least one in five Russian infants are born in poor health. The good news is that programs are underway in both countries, with help from the global community, to clean up pollution and improve the health of their inhabitants.
Lead in Human Bones
There is a continuing effort to improve the methodology for accurately measuring lead in humans. The X-ray fluorescent measurement of lead in bone is intended to supplement and not replace other sampling procedures. Todd and Chettle (p. 172) review the K and L X-ray techniques, which noninvasively measure lead in bone, describe the advantages of repeated measurements in human subjects, and summarize research priorities for the future.
Formate as a Biomarker of Methanol Exposure
D'Alessandro et al. (p. 178) assayed formate in blood and urine of humans to determine its utility as an indicator of toxicity and exposure to the gasoline additive methanol. Formate is the metabolite responsible for the neurological and ocular symptoms associated with methanol toxicity. Adult male and female subjects were exposed to methanol vapors in whole-body exposure chambers for four hours at the NIOSH permissible exposure limit for methanol, 200 ppm. Subjects were sampled throughout the four-hour exposure and four hours thereafter. Serum and urine formate concentrations were not elevated at any interval, and therefore cannot serve as a biological marker of low-dose methanol exposure.
Bioavailability of Arsenic in Soil
Bog ore-containing soils in the Netherlands often contain arsenic at 10 times the allowable limits. Groen et al. (p. 182) gave dogs intravenous injections of arsenic or oral doses of the contaminated soil to calculate the bioavailability of arsenic and to estimate potential human risks from soil ingestion. They found that 8% of arsenic from the soil was bioavailable, in contrast to earlier studies showing 1% bioavailability. Their study suggests that risk assessments of arsenic in soil need to be revised.
Increased Mortality Risk from Air Particulates
An association between total suspended particulate matter in the air and mortality has been consistently reported across the United States and was emphasized by the London smog disaster in 1952, when striking increases in mortality occurred. Schwartz (p. 186) investigated the relationship between total suspended particluates and mortality in Cincinnati, Ohio, and showed that the relative risk of death increases for each 100 µg/m3 increase in air particulates and is higher for the elderly and for deaths due to pneumonia and cardiovascular disease.
Products from Cooked Food Cause Cancer and Heart Lesions
Although heterocyclic aromatic amines are only formed in nanogram/gram amounts during cooking of fish, fowl, pork, and beef, 19 of these compounds were shown to be extremely potent mutagens, and 10 were carcinogenic in rodents. Adamson et al. (p. 190) reports the long-term toxicity of one of these compounds, 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), in primates. Liver cancer occurred in monkeys exposed to low doses and high doses of IQ, but in none of the control monkeys. The average latency period was 43-60 months. The authors conclude that IQ could also be a potential carcinogen for humans.
In a companion report, Thorgeirsson et al. (p. 194) examined monkeys exposed to two lower doses of IQ five days per week for 48-80 months. They observed cardiac lesions by light and electron microscopy, but no clinical evidence of heart damage. The authors suggest these changes represent initial stages of toxicity and that chronic exposure to high doses of IQ might cause progressive heart damage.
PCB and DDT Associated with Liver Lesions in Fishes
Myers et al. (p. 200) evaluated pollutants in sediment and tissues of English sole, starry flounder, and white croaker in 27 locations on the Pacific Coast from Alaska to Southern California. They report a strong association between neoplastic or non-neoplastic liver lesions and the sum concentrations of PCB or DDT in fish from urban bay locations. The data suggest that these contaminants are significant risk factors for hepatoxicity in bottom-dwelling species and underline the utility of liver histopathology as a biomarker of contamination in fish.
Sulfite Affects BaP Binding to Respiratory Epithelial Cells
Cultured cells from mouse respiratory epithelia were exposed to benzo[a]pyrene (BaP) metabolites plus sulfite ions. Green et al. (p. 216) found that 10 mM sulfite doubled the nuclear localization of BaP metabolites previously added to cultured cells, resulting in a 200% increase in nuclear DNA-bound material. The data suggested a novel BaP metabolite was formed intracellularly and that the more stable DNA-BaP derivative probably could not leave, extending the residence time in the cell for more potential modification of DNA.
Last Update: August 21, 1998 |