'Hale and Hearty
Inhaled toxicants can affect not only the nasal passages and lungs but also many other systems within the body. The NIEHS Respiratory Toxicology Group, highlighted in this month's NIEHS News (p. A168), studies the diverse effects of inhaled toxicants such as mercury and occupational hazards including styrene and vanadium pentoxide.
Reining in Air Pollution
Air pollutants are notorious for slipping uninvited across international borders. The Focus (p. A170) examines several recent conferences, treaties, and projects around the world that are aimed at limiting the amount of air pollution that leaves originating countries.
Making (and Breaking?) the Rules
Under the gun to protect the health of the American public, regulatory agencies such as the U.S. EPA must sometimes rely on less than rock-solid scientific evidence in setting standards. Some groups feel this is a violation of the Constitution and an abuse of power. The Spheres of Influence (p. A176) looks at the whys and wherefores of the agency's tighter new air pollution standards.
Scrubbing Bubbles
Bacteria have been used to process waste on the ground for years--now they're being used in the air, too. The Innovations (p. A178) describes new biofiltration technology that uses microbes to clean volatile organic compounds, hazardous air pollutants, and odorous emissions from polluted air.
The Environmental Genome Project
Sharp and Barrett (p. 279) comment on the ethical, legal, and social implications of the project being conducted by the National Institute of Environmental Health Sciences, pointing out that individual genetic information complicates traditional issues in bioethics.
Mortality and Air Particulates in Europe
Peters et al. (p. 283) reassessed the association between mortality and elevated concentrations of air particulates in Central Europe. Between 1982 and 1994 there was an increase in mortality of 3.4% in association with 100 µg/m3 total suspended particles in the Czech Republic. The mortality associated with air pollution was consistent with observations in other western European cities and the United States.
Cadmium and Hemochromatosis
Iron absorption is greatly increased in individuals with hereditary hemochromatosis, a genetic disease that results in pigmented skin and liver disease. Akesson et al. (p. 289) examined patients who were treated by bloodletting and found that they exhibited increased blood cadmium levels. The authors report that treatment rather than the disease gave rise to increased cadmium uptake, suggesting that cadmium absorption depends on both the genotype and the treatment by bloodletting.
Neurotoxicity among Termiticide Applicators
Steenland et al. (p. 293) analyzed neurologic function in 191 termiticide applicators who used chlorpyrifos and in 189 controls. A urinary metabolite of chlorpyrifos was approximately 100 times higher in recently exposed applicators as compared to the general U.S. population. However, there were no differences in clinical exams and only minor differences in neurobehavioral skills between applicators and controls; as in earlier studies, the exposed subjects did report more symptoms and perform worse in some neurologic tests than unexposed subjects, which could be reason for concern. (Also see Science Selections, p. A182)
Predictors of Allergen Levels
The prevalence and adverse effects of childhood asthma are highest in less affluent minority communities. Kitch et al. (p. 301) report that dust mite and cockroach allergens are prevalent in urban Boston, Massachusetts, neighborhoods, and especially in households with low incomes.
Lead in Calcium Supplements
Over the last 20 years some calcium supplements have undergone a systematic reduction in contaminant lead, but because of the methods used, measurements of lead in some of these supplements may be erroneously low by as much as 50% below currently employed detection limits. Using rigorous analytical techniques, Scelfo and Flegal (p. 309) report that some calcium supplements contain lead concentrations that still exceed new California criteria of 1.5 µg lead/g calcium.
Balancing Risks of Drinking Water Disinfection
Havelaar et al. (p. 315) use the applicability of disability adjusted life-years (DALYs) as a principle to quantitate risk of renal cell cancer by bromate that arises from water treatment by ozonation as compared to the risk of infection with Cryptosporidium parvum. Ozonation reduces infection approximately sevenfold, but bromate is produced at levels above current health guidelines. Nevertheless, health benefits of preventing gastroenteritis outweighs losses by premature death from renal cell cancer by a factor of more than 10, resulting in a net benefit of about 1 DALY/million person-years.
Serum Methyleugenol in Americans
Barr et al. (p. 323) employed isotope dilution gas chromatography-high resolution mass spectrometry to evaluate methyleugenol in adult serum samples. The chemical was present in 98% of 206 samples obtained from the Third National Health and Nutrition Examination Survey, with a mean concentration of 24 pg/g. (Also see Science Selections, p. A182)
Hormone Mimics Disrupt Steroids in Turtles
Willingham et al. (p. 329) used the red-eared slider turtle to examine the deleterious effects of hormone-mimicking chemicals on sexual determination. They show that exposure of the eggs to environmentally relevant concentrations of chlordane, aroclor 1242 (PCB), and trans-nonachlor alter the levels of sex steroid hormones in otherwise normally appearing adult animals.
Benzene and Smoking-Induced Leukemia
Korte et al. (p. 333) assessed the proportion of smoking-induced leukemia and acute myeloid leukemia attributable to the benzene in cigarette smoke. The authors report that benzene was responsible for approximately one-tenth to one-third of smoking-induced leukemia and for up to three-fifths of smoking-related acute myeloid leukemia, based on risk estimates of linear extrapolations from empirical data over a dose range of 10- to 100-fold. (Also see Science Selections, p. A182)
Asbestos Causes Mutagenesis in Transgenic Mice
Rihn et al. (p. 341) used the lacI reporter gene in transgenic mice to determine the mutagenicity of asbestos administered by nose-only exposure at 5.75 mg/m3 crocidolite dust for 6 hr/day for 5 days. There was a doubling of the mutation frequency in treated mice 4 weeks after exposure, showing that mutagenesis was an early event in fiber intoxication that was evoked by cell transformation due to asbestos exposure.
Air Pollution and Mortality in the Elderly
Mar et al. (p. 347) investigated the relationship between air pollution and nonaccidental and cardiovascular mortality in residents older than 65 years of age in Phoenix, Arizona. Total mortality was associated with carbon monoxide and nitric oxide; cardiovascular mortality was associated with these gases, sulfur dioxide, and the PM2.5, PM10, and coarse fraction air particulates.
Adolescent Health and the Environment
Golub (p. 355) reviews the unique coincidence of maturation, socialization, and novel exposures of adolescents in reference to their health and the environment. Their reproductive, respiratory, skeletal, immune, and central nervous systems are maturing at a time of increased risk for infectious disease and accidental injury; pharmacokinetics are altered as blood volume, respiration, metabolism and capacity change; potential exposures change with increased food intake and possible voluntary drug intake; and adolescents are introduced to contaminants in the workplace. The author emphasizes the need for animal models that are appropriate for these distinctive human developmental stages and the need for risk assessment strategies that account for adolescent pharmacokinetic and lifestyle factors.
Respiratory Toxicity from Nitrates in Water
Children up to 8 years of age who lived in five different villages with drinking water sources containing 26-459 mg nitrate ion/L were examined by Gupta et al. (p. 363). The authors examined acute respiratory infection in the children and suggested that methemoglobinemia secondary to high nitrate ingestion in drinking water was a major cause of respiratory toxicity, leading to alveolar damage and decreased pulmonary circulation.
Multiple Chemical Sensitivities
Kipen and Fiedler (p. 377) report on multiple chemical sensitivities in a 37-year-old mechanic who was exposed to an unknown gas or vapor while working on an air-conditioning unit. The authors suggest that treatment for multiple chemical sensitivities should include avoiding substances that cause the most symptoms and minimizing exposures, and identifing symptoms that are associated with fear of exposure.
Last Updated: April 4, 2000
