A bleak warning issued in a Commentary by Cairns and Bidwell implies that mankind mistakenly believes natural systems are incapable of altering human society and argues that reluctance by mankind to practice sustainable use of resources could result in replacement of useful species by pests leading to disease and famine.
Secondhand, sidestream, passive, or inadvertant. Call it what you will, new reports of adverse health effects from exposure to environmental tobacco smoke are giving credence to the complaints of nonsmokers, which for years have been brushed aside as mere annoyance. The Focus describes the evidence piling up against secondhand smoke and the tobacco industry's response.
Government regulators and industry representatives have a long history of disagreement over the scope and nature of environmental regulations and requirements. As the Spheres of Influence describes, some of this disagreement may be turning into détente as voluntary programs and new government initiatives attempt to bridge the gap between the disparate views on how to solve environmental problems.
The Innovations offers a new solution to the mounting problem of how to dispose of too many used automobile tires. Researchers at Pacific Northwest National Laboratories have developed a biodesulfurization process using a bacteria to leach sulfur from rubber molecules, leaving a substance that can be recycled into a material usable for new tires.
Mastrangelo et al. review recent epidemiological studies on the carcinogenic effects of PAHs in occupationally exposed humans. The authors report that the current threshold limit value for benzene soluble matter (indicative of PAH exposure) is unacceptable, suggesting that 40 years exposure involves a relative risk of 1.2 to 1.4 for lung cancer and 2.2 for bladder cancer.
An investigation by Seidel et al. of PCBs in classrooms revealed the presence of polychlorinated terphenyls (PCTs) around fluroescent light frames. The compounds were found to be predominantly associated with particulate matter; their identity was confirmed by GS-MS. A review indicates that the toxicity of PCTs is similar to that of PCBs and that there is ubiquitous distribution in the environment; PCTs may represent a new class of important indoor contaminants.
Miguel et al. demonstrated that latex allergen or latex cross-reactive material was present in sediment and airborne particulate matter derived from vehicular tire debris. The authors suggest that heavy traffic could be a factor in producing latex allergy and asthma symptoms associated with urban air pollution.
Although previous studies reported that 60-Hz magnetic fields altered gene function in Syrian hamster embryo cells and in C3H/10T1/2 murine fibroblast cells, extensive re-testing by Balcer-Kubiczek of such reponses was negative, casting doubt on a promotional role for magnetic fields.
The proposal that saturation of biomethylation capacity for inorganic arsenic might lead to a carcinogenicity threshold was examined by Hopenhayn-Rich et al. A biomarker study of the relative distribution of urinary inorganic arsenic, monomethylarsonate, and dimethylarsinate was conducted in a Chilean population chronically exposed to water contaminated with high arsenic levels. Data suggest that changes observed in percent inorganic arsenic and in the ratio of the metabolites of arsenic are not supportive of a threshold for arsenic carcinogenicity.
A population survey of about 10,000 children between 1 and <5 years of age living in impoverished conditions north of Mexico City indicated that 21% (1,987) had blood lead levels high enough to require medical intervention ( 20 g/dl to 40 g/dl). López-Carrillo et al. demonstrate the need to strengthen health education programs to promote reduction of lead exposure incurred from use of lead- glazed pottery and chewing on lead-paint contaminated colored pencils.
In a computer-assisted study of semen analysis, Tablado et al. investigated the effects of static magnetic fields on maturation of sperm motility in mice. Exposure of animals to a field of 0.7 T over 10 or 35 days for either 1hr or 24hr/day did not cause any deleterious effects on male reproductive health, as judged by sperm motility and reproductive organ weight.
Disease development in flounder in large 40 m x 40 m x 3 m mesocosms flushed by Wadden Sea saltwater in the The Netherlands was studied by Vethaak et al.. Dredge spoil from a harbor contaminated with a complex mixture of organic micropollutants and heavy metals was introduced at high and medium levels into one of the three mesocosms, causing a progression of epidermal disease, four cases of hepatocellular adenomas, and associated liver lesions in flounder sampled every six months for three years.
Asians living in Washington State consume tissues from razor clams and dungeness crabs that contain toxic levels of domoic acid, a neuroexcitatory amino acid. A tolerable daily intake for seafood containing domoic acid was estimated for sensitive individuals by Mariën . The primary health effects associated with domoic acid toxicity (vomiting, cramps, diarrhea, confusion, disorientation, and other neurological effects) can be averted if concentrations do not exceed 30 mg/kg in hepatopancreas and viscera of dungeness crabs or 20 mg/kg in razor clams.
Last Update: October 9, 1997 |