Previous research updated the mortality experience of North American synthetic rubber industry workers during the period 1944-1998, determined if leukemia and other cancers were associated with several employment factors and carried out Poisson regression analysis to examine exposure-response associations between estimated exposure to 1,3-butadiene (BD) or other chemicals and cancer. The present study used Cox regression procedures to examine further the exposure-response relationship between several unlagged and lagged, continuous, time-dependent BD exposure indices (BD parts per million (ppm)-years, the total number of exposures to BD concentrations >100 ppm ("peaks") and average intensity of BD) and leukemia, lymphoid neoplasms and myeloid neoplasms. All three BD exposure indices were associated positively with leukemia. Using continuous, untransformed BD ppm-years the regression coefficient (beta) from an analysis that controlled only for age was 2.9 x 10(-4) (p
1,3-Butadiene has been assessed as a Priority Substance under the Canadian Environmental Protection Act. The general population in Canada is exposed to 1,3-butadiene primarily through ambient air. Inhaled 1,3-butadiene is carcinogenic in both mice and rats, inducing tumors at multiple sites at all concentrations tested in all identified studies. In addition, 1,3-butadiene is genotoxic in both somatic and germ cells of rodents. It also induces adverse effects in the reproductive organs of female mice at relatively low concentrations. The greater sensitivity in mice than in rats to induction of these effects by 1,3-butadiene is likely related to species differences in metabolism to active epoxide metabolites. Exposure to 1,3-butadiene in the occupational environment has been associated with the induction of leukemia; there is also some limited evidence that 1,3-butadiene is genotoxic in exposed workers. Therefore, in view of the weight of evidence of available epidemiological and toxicological data, 1,3-butadiene is considered highly likely to be carcinogenic, and likely to be genotoxic, in humans. Estimates of the potency of butadiene to induce cancer have been derived on the basis of both epidemiological investigation and bioassays in mice and rats. Potencies to induce ovarian effects have been estimated on the basis of studies in mice. Uncertainties have been delineated, and, while there are clear species differences in metabolism, estimates of potency to induce effects are considered justifiably conservative in view of the likely variability in metabolism across the population related to genetic polymorphism for enzymes for the critical metabolic pathway.
4-Nonylphenol (NP) and bisphenol A (BPA) are phenolic substances used in high volumes by the industry. Studies on cells and in experimental animals have shown that both these compounds can be classified as estrogenic hormone disrupters. Information about the exposure of humans to NP and BPA is still scarce, especially regarding levels in human blood. The first aim of this study was to investigate possible sources of NP and BPA exposure from food, by analyzing the levels of NP and BPA from a Swedish food market basket, based on the Swedish per capita food consumption. A second aim was to investigate blood serum levels of NP and BPA, as well as NP-ethoxylates, among young women in Sweden (n=100). Moreover, associations between food consumption and blood NP and BPA levels were studied. In food, NP was to some extent found at levels above limit of quantification (LOQ 20 ng/g fresh weight) in fruits, cereal products, vegetables, and potatoes. BPA levels above LOQ (2 ng/g fresh weight) were found in fish, meats, potatoes, and dairy products. The estimated mean intakes per capita were (medium bound) 27 µg NP/day and 3.9 µg BPA/day, showing that food is a source of BPA and NP in the general Swedish population. In blood serum, free NP above limit of detection (LOD 0.5 ng/g) was detected in 46% of the study participants while detectable levels of total NP (LOD 0.8 ng/g) were observed in 43%. The corresponding percentages for BPA were 25% and 22%, respectively. The results indicate that there is a continuous source of exposure to NP and BPA that is high enough for free NP and BPA to be detected in some consumers. Among the participants with quantifiable levels of free and total NP (n=38), 85% (median, range: 38-112%) of the NP was present as free NP. For BPA 76% (49-109%) was detected as free BPA (n=15). All women had levels of ethoxylates of NP below LOD (0.1-0.7 ng/g). A significantly higher total consumption of fruits and vegetables was reported in questionnaires by participants with NP levels at or above LOD than among women with levels below LOD. This result is supporting the market basket results of relatively high NP levels in these types of food.
This study documents the radiation doses received by all in-room personnel of three cardiac catheterization laboratories where more than 15,000 cardiac procedures have been performed over a 5-y period. It is shown that all in-room personnel was exposed to a body dose equivalent well below any regulatory limits. However, some workers may have exceeded the occupational 150 mSv y-1 recommended limit for the lens of the eye. The physicians-in-training and the staff physicians are the two groups more likely to reach this limit. It is also demonstrated that a low correlation exists between the annual number of procedures and the annual head dose equivalent of a physician, but more variation is likely to originate from his/her working attitude and techniques. The mean dose equivalent at the collar level of the physicians is estimated to be 0.04 +/- 0.02 mSv per procedure.
Ten cases of angiosarcoma of the liver among vinyl chloride workers from a plant in Shawinigan, Québec, are reported. The author insist mostly on the occupational history of these workers and on the morphologic description of the lesions. A pathogenic hypothesis is submitted.
p-Phenylenediamine (PPD) is an important allergen; 5.0% of patients tested positive to PPD when patch-tested, according to the North American Contact Dermatitis Group. Hair dyes are the main source of exposure.
To assess the significance of PPD allergy at the Ottawa Patch Test Clinic.
We assessed the epidemiology of PPD allergies and determined the cross-reactivity with other para-amino compounds. Charts of patients visiting the Ottawa Patch Test Clinic between May 1997 and July 2009 were reviewed.
One hundred thirty-four patients were found to have a contact allergy to PPD; 75.4% were female, 24.6% were male, 13.4% were hairdressers, 18.7% had a history of atopy, 90.3% were sensitized by hair dye, 2.2% were sensitized by henna tattoos, and 7.5% were sensitized by other sources. Positive patch-test reactions to textile dyes were seen in 24.6%, 7.5% reacted to benzocaine, 6.0% reacted to sulfa drugs, 1.5% reacted to isopropyl-para-phenylenediamine, and 1.5% reacted to para-aminobenzoic acid.
PPD is an important source of allergic contact allergy. Our results show a significant relationship of PPD with other related para-amino compounds.