Historical occupational isocyanate exposure levels in two Canadian provinces

Effects Of Chronic Exposure to Paint Fumes Among Artisans in Lagos State, Nigeria

The chronic effects of automobile paint fumes and their volatile organic constituents form detrimental air pollution with hazardous consequences especially to paint industrial workers and the population within the vicinity. This study investigated the chronic effects of exposure to paint fumes in Mushin area of Lagos, Nigeria. Fifty artisans employed in automobile painting industries were compared with 50 control group whose work does not expose them to paint fumes. Five milliliters blood was collected and used for assessment of hematological and biochemical parameters. This was compared in artisan and unexposed control group and p value of < 0.05 indicates significant difference. In artisans, kidney function analysis showed a significant decrease in potassium (3.63 ± 0.1012 mEq/L) compared to healthy control (4.26 ± 0.1699 mEq/L, p = 0.0049), as well as bicarbonate ion concentration (23.89 ± 0.3795 vs 26.40 ± 0.3578 mmol/L respectively, p = 0.0011), however, a significant increase in creatinine level was recorded in artisans than control group (1.140 ± 0.1075 vs 0.76 ± 0.03578 mg/dL, p = 0.03); which is an indicator of renal function impairment. AST and ALT levels were significantly higher in artisans (11.44 ± 0.8190 and 8.78 ± 0.7558 U/L) compared to control group (6.83 ± 0.3086 and 6.67 ± 0.3354 U/L), respectively (p < 0.05), while ALP levels were similar. For oxidative stress parameters - CAT, MDA and protein, there was a significant increase in artisans while the corresponding GSH and SOD activities decreased significantly (p < 0.05). The results showed similar Zinc and Chromium levels in both groups but Lead was not detected in any participant. The findings of this study indicate that chronic exposure to paint fumes among automobile painting artisans may impair renal function, liver function and induce oxidative damages. Creating awareness of potential dangers and recommending use of personal protective equipment among automobile painting artisans can further decrease their exposure.ga1

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Prolonged exposure to hazardous components of paint like heavy metals used as solvents in the paints have health implications.

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Chronic exposure to paint fumes in automobile artisans may impair renal, liver function, induce oxidative stress and toxicity.

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Implementing use of protective equipment in artisans will reduce occupational hazard and toxicity due to heavy metal exposure.

Development of Quantitative Estimates of Wood Dust Exposure in a Canadian General Population Job-Exposure Matrix Based on Past Expert Assessments

Objectives

The CANJEM general population job-exposure matrix summarizes expert evaluations of 31 673 jobs from four population-based case-control studies of cancer conducted in Montreal, Canada. Intensity in each CANJEM cell is represented as relative distributions of the ordinal (low, medium, high) ratings of jobs assigned by the experts. We aimed to apply quantitative concentrations to CANJEM cells using Canadian historical measurements from the Canadian Workplace Exposure Database (CWED), taking exposure to wood dust as an example.

Methods

We selected 5170 personal and area wood dust measurements from 31 occupations (2011 Canadian National Occupational Classification) with a non-zero exposure probability in CANJEM between 1930 and 2005. The measurements were taken between 1981 and 2003 (median 1989). A Bayesian hierarchical model was applied to the wood dust concentrations with occupations as random effects, and sampling duration, year, sample type (area or personal), province, and the relative proportion of jobs exposed at medium and high intensity in CANJEM cells as fixed effects.

Results

The estimated geometric mean (GM) concentrations for a CANJEM cell with all jobs exposed at medium or high intensity were respectively 1.3 and 2.4 times higher relative to a cell with all jobs at low intensity. An overall trend of -3%/year in exposure was observed. Applying the model estimates to all 198 cells in CANJEM with some exposure assigned by the experts, the predicted 8-hour, personal wood dust GM concentrations by occupation for 1989 ranged from 0.48 to 1.96 mg m-3.

Conclusions

The model provided estimates of wood dust concentrations for any CANJEM cell with exposure, applicable for quantitative risk assessment at the population level. This framework can be implemented for other agents represented in both CANJEM and CWED.

Critique of the ACGIH 2016 derivation of toluene diisocyanate Threshold Limit Values

In 2016, the American Conference of Governmental Industrial Hygienists (ACGIH) lowered the 8-hr Threshold Limit Value - time-weighted average (TLV-TWA) for toluene diisocyanate (TDI) from 5 ppb to 1 ppb, and the 15-min short-term exposure limit (STEL) from 20 ppb to 5 ppb. We evaluated ACGIH's basis for lowering these values. It is our opinion that the ACGIH's evaluation of the evidence for occupational asthma and respiratory effects from TDI exposure does not fully integrate the results of all the available human and animal studies. We found that some studies reported occupational asthma cases at TWAs less than 5 ppb, but these cases were likely caused by peak exposures above 20 ppb. Advances in industrial hygiene have reduced peak exposures and the incidence of upset conditions, such as spills and accidents, in modern TDI facilities. Taken together, the human evidence indicates that adherence to the previous 8-hr TLV-TWA and 15-min STEL (5 ppb and 20 ppb, respectively) prevents most, if not all, cases of occupational asthma, and eliminates or reduces the risk of lung function decrements and other respiratory effects. While limited, the animal literature supports the human evidence and indicates that TDI-induced asthma is a threshold phenomenon. We conclude that ACGIH's decision to lower the TLV-TWA and STEL values for TDI is not adequately supported.