Acute wood or coal exposure with carbon monoxide intoxication induces sister chromatid exchange

Indoor wood-burning from stoves and fireplaces and incident lung cancer among Sister Study participants

BACKGROUND AND AIM

Epidemiological studies conducted mostly in low- and middle-income countries have found a positive association between household combustion of wood and lung cancer. However, most studies have been retrospective, and few have been conducted in the United States where indoor wood-burning usage patterns differ. We examined the association of exposure to indoor wood smoke from fireplaces and stoves with incident lung cancer in a U.S.-wide cohort of women.

METHODS

We included 50,226 women without prior lung cancer participating in the U.S.-based prospective Sister Study. At enrollment (2003-2009), women reported frequency of use of wood-burning stoves and/or fireplaces in their longest-lived adult residence. Cox regression was used to estimate adjusted hazard ratios (HRadj) and 95 % confidence intervals (CI) for the association between indoor wood-burning fireplace/stove use and incident lung cancer. Lung cancer was self-reported and confirmed with medical records.

RESULTS

During an average 11.3 years of follow-up, 347 medically confirmed lung cancer cases accrued. Overall, 62.3 % of the study population reported the presence of an indoor wood-burning fireplace/stove at their longest-lived adult residence and 20.6 % reported annual usage of ≥30 days/year. Compared to those without a wood-burning fireplace/stove, women who used their wood-burning fireplace/stove ≥30 days/year had an elevated rate of lung cancer (HRadj = 1.68; 95 % CI = 1.27, 2.20). In never smokers, positive associations were seen for use 1-29 days/year (HRadj = 1.64; 95 % CI = 0.87, 3.10) and ≥30 days/year (HRadj = 1.99; 95 % CI = 1.02, 3.89). Associations were also elevated across all income groups, in Northeastern, Western or Midwestern U.S. regions, and among those who lived in urban or rural/small town settings.

CONCLUSIONS

Our prospective analysis of a cohort of U.S. women found that increasing frequency of wood-burning indoor fireplace/stove usage was associated with incident lung cancer, even among never smokers.

Use of carboxyhemoglobin as a biomarker of environmental CO exposure: critical evaluation of the literature

Carbon monoxide (CO) poisoning is the primary cause for access to emergency department (ED) services for more than 50,000 persons in Europe and the USA every year. CO poisoning diagnosis is based on multiple factors and is usually confirmed by high carboxyhemoglobin (COHb) levels in the blood. We conducted a systematic evaluation of literature to investigate the usefulness of COHb as a biomarker of environmental CO exposure. We conducted an electronic search in Medline, Embase, and the Cochrane Library databases. We selected studies reporting high or low environmental CO concentrations, as well as COHb levels in exposed subjects presenting in ED or staying at home. We included 19 studies, but only 7 studies reported environmental CO concentration and proved a correlation between COHb and CO exposure in healthy and non-smoker subjects only. However, confounding factors were often incompletely assessed. The main symptoms reported were headache, nausea, vertigo and vomiting. COHb data stored in healthcare databases were used in six studies and provided useful information about symptoms, CO sources and patient characteristics. Most studies were classified at risk of bias. This review indicates that COHb is the most commonly used biomarker to assess CO exposure and seems to be useful. Further studies are needed to establish the reliability of COHb as a biomarker and/or explore other possible biomarkers. Surveillance systems of the general population, correlated with geographical locations and other confounding factors, could be important for CO exposure monitoring and the development of focused prevention programs.

Occupational exposure to gases, polycyclic aromatic hydrocarbons and volatile organic compounds in biomass-fired power plants

The combustion of fuels produces air pollutants in the form of gases, organic compounds, and particulate matter. However, although the environmental aspect of these agents has been examined, workers' exposure to them is still a neglected issue. The purpose of this study was to measure maintenance and ash removal workers' multiple exposures to gases, volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs) during their work tasks in biomass-fired power plants. Our hygienic measurements revealed that carbon monoxide, nitric oxide, ammonia and sulfur dioxide were the most common gases that the workers were exposed to during their tasks. Their average concentrations were 0.45 ppm, 0.06 ppm, 0.11 ppm and 0.42 ppm, respectively. Phenanthrene and naphthalene were the most prominent PAHs. At the same sampling points, the most commonly found VOCs were aromatic and aliphatic hydrocarbons and turpentines. The calculated total PAH concentrations were less than 7% of benzo[a]pyrene's eight-hour occupational exposure limit, and the total VOC concentrations were below the Finnish reference value for the normal industrial level in all measured work tasks. The most evident health effect caused by multiple exposures to gases was upper respiratory track irritation, followed by the disruption of oxygen transport, and finally central nervous system disorders. We recommend powered air respirators with ABEK+P3 cartridges and carbon monoxide gas detectors as the minimum requirement for those working inside biomass-fired power plant boilers, and compressed air breathing apparatus as the best form of protection.

Relationship between carbon monoxide intoxication and sister chromatid exchange in lymphocytes

Aim:

Carbon monoxide (CO) intoxication can be serious and is reported to be the cause of more than half of all fatal intoxications. In this study, we aimed to identify its genotoxic effects based on sister chromatid exchange (SCE).

Materials and methods:

CO-poisoned patients presented to the emergency services department were identified. Their demographic characteristics, vital findings, laboratory markers, source of CO gas, risk factors, and smoking habits were recorded. The genotoxic effect was assessed using the SCE method.

Results:

A total of 38 patients were recruited. Their ages ranged from 16–64 years (mean: 29.79 ± 10.92 years). In all the cases, the source of CO gas was a flash heater. The mean carboxyhemoglobin (COHb) level was 25.05 ± 7.15%. Of all the patients, 12 (31.6%) had a the Glasgow Coma Scale (GCS) scores of less than 15, and an important negative correlation was found between the GCS and COHb level ( r = −0.825; p < 0.001). Genotoxicity investigations revealed a significantly higher SCE frequency among patients with high COHb levels compared with that of control subjects with physiological COHb levels ( p < 0.001). However, no correlation between increased SCE frequency and COHb level was found ( r = 0.16; p = 0.34).

Conclusion:

CO poisoning was shown to result in genotoxicity via an increase in the frequency of SCE. This study is the first to demonstrate a genotoxic effect of CO independent of other chemicals.

Cytogenetic damage in workers from a coal-fired power plant

The aim of this study was to investigate the genotoxic risk to workers occupationally exposed to coal combustion products in Afsin-Elbistan A power plant, located in south-eastern Turkey. We analysed chromosomal aberrations (CAs), polyploidy, sister-chromatid exchanges (SCEs), and micronuclei (MN) in 48 male workers without a history of smoking, tobacco chewing, or alcohol consumption. The results were compared with a control group of 30 healthy male individuals without exposure to any known genotoxic agents. The mean frequencies of CA, polyploidy, SCEs (P<0.01), and MN (P<0.05) were significantly higher in workers than in the control group, by the Mann-Whitney U-test. Spearman's rho correlation analysis revealed a significant increase in the frequency of CA and MN with increasing years of exposure (P<0.05). However, there was no significant effect of age on the cytogenetic markers analysed in both groups (P>0.05). The data obtained from this study clearly showed chromosomal hazard in the peripheral lymphocytes of workers exposed to coal combustion products in Afsin-Elbistan A power plant for several years. This cytogenetic damage might be attributed to the cumulative effects of several substances due to chemical complexity of the coal ash and gaseous emissions rather than a specific substance.