Toxicology and Industrial Health

Background: A secondary spontaneous pneumothorax is a complication of an underlying pulmonary disease. In recent years, there have been only a few scattered reports of patients with silicosis also having a pneumothorax. Silicosis, a form of disabling pulmonary fibrosis, is a well-known occupational disease resulting from high-level exposure to silica or silica-containing dusts. The objective of the present study was to elucidate any associations between the occurrence of a pneumothorax, and pulmonary function tests and clinical observations performed prior to the pneumothorax; these two factors may be predictors for a pneumothorax among workers exposed primarily to silica-containing respirable dust. Methods: A diagnosis of silicosis was made on several factors: silica dust exposure, appropriate interval of time after exposure, clinical findings, pulmonary function tests and chest radiological findings. A checklist was designed for collecting data of occupational history, respiratory signs, and symptoms from onset of dust exposure to the occurrence of a pneumothorax. Spirometery was conducted in accordance to the recommendations of standard protocols and guidelines posited by the American Thoracic Society. Autopsies were performed in three cases where the patient had suffered a pneumothorax due to silicosis. Mann—Whitney U-tests and Fisher's exact tests were used to determine any associations between pneumothorax and predictor factors. Results: An association between a progressive decrease in pulmonary function test values and a pneumothorax was observed. The occurrence of a pneumothorax was associated with complaints of pleuretic chest pain, resting dyspnea, respiratory distress, paroxysmal nocturnal dyspnea, orthopnea and crackle. Conclusion: A characteristic decline in pulmonary function test values and the severity of respiratory impairment may facilitate the occurrence of a pneumothorax in silicosis. Toxicology and Industrial Health 2007; 23: 125—132.

Suspended particles, of which bioaerosols are one type, constitute one of the main reasons to cause severe air quality in Taiwan. Bioaerosols include allergens such as fungi, bacteria, actinomycetes, arthropods and protozoa, as well as microbial products such as mycotoxins, endotoxins and glucans. When allergens and microbial products are suspended in the air, local air quality will be influenced severely. In addition, when the particle size is small enough to pass through the respiratory tract entering the human body, the health of the local population is also threatened. Therefore, the purpose of this study attempted to understand the concentration and types of bacteria during summer period at four sampling sites in Taichung city, central Taiwan. The results indicated that total average bacterial concentration by using R₂A medium incubated for 48 h were 7.3 × 10² and 1.2 × 10³ cfu/m³ for Chung-Ming elementary sampling site during daytime and night-time period of summer season. In addition, total average bacterial concentration by using R₂A medium incubated for 48 h were 2.2 × 10³ and 2.5 × 10³ cfu/m³ for Taichung refuse incineration plant sampling site during daytime and night-time period of summer season. As for Rice Field sampling site during daytime and night-time period of summer season, the results also reflected that the total average bacterial concentration by using R₂A medium incubated for 48 h were 3.4 × 10³ and 3.5 × 10³ cfu/m³. Finally, total average bacterial concentration by using R₂A medium incubated for 48 h were 1.6 × 10³ and 1.9 × 10³ cfu/m³ for Central Taiwan Science Park sampling site during daytime and night-time period of summer season. Moreover, the average bacterial concentration increased as the incubated time in a growth medium increased for particle sizes of 0.65—1.1, 1.1—2.1, 2.1—3.3, 3.3—4.7 and 4.7—7.0 μm. The total average bacterial concentration has no significant difference for day and night sampling period at any sampling site for the expression of bacterial concentration in term of order. The high average bacterial concentration was found in the particle size of 0.53—0.71 mm (average bioaerosol size was in the range of 2.1—4.7 μm) for each sampling site. Besides, there were exceeded 20 kinds of bacteria for each sampling site and the bacterial shape were rod, coccus and filamentous. Toxicology and Industrial Health 2007; 23: 133—139.

1,3-Butadiene is one of the most commonly produced chemicals in the United States. It is also a known human and animal carcinogen. Information about 1,3-butadiene induced neurotoxicity is scarce. In this study, we evaluated the outcome of 1,3-butadiene accidental contact on neurological function in humans known to be environmentally exposed to the chemical. Known clinical neurological criterions were applied for the identification and evaluation of 1,3-butadiene neurotoxicity. Statistical analysis was conducted on the collected neurological parameters from a random cohort of 310 patients who had been environmentally exposed to 1,3-butadiene and compared with a cohort of 50 matched individuals with similar backgrounds but who were not exposed to 1,3-butadiene (control). Results indicate that 1,3-butadiene has met the criteria and features of a neurotoxin. Exposure to 1,3-butadiene provokes neurological risks that were reversible in most patients. About 6% (18 patients) of the exposed patients demonstrated irreversible neurotoxicity that may need to be longitudinally scrutinized. Toxicology and Industrial Health 2007; 23: 141—146.

The Agency for Toxic Substances and Disease Registry (ATSDR) was requested to review the analytical results of tissue samples from fish caught in the Penobscot river in Maine, calculate fish consumption limits and provide a public health opinion regarding the health implications associated with eating the contaminated fish. Fish consumption limits were calculated to provide guidance on the amount of fish that a person may eat monthly that would probably not pose a public health threat. Earlier, in 1987, the Maine Bureau of Health (BOH) issued a fish consumption advisory for portions of the Penobscot river to protect the public from exposures to dioxins/furans and methyl mercury-contaminated fish. From 1988 to 2003 the state of Maine conducted fish surveys at four locations along the Penobscot river to monitor the levels of dioxins/furans and methyl mercury contamination. In 2005, ATSDR reviewed the sampling results for two fish species (i.e., bottom feeders and predators) collected from the Penobscot river that revealed various levels of dioxins/furans and methyl mercury. The United States Environmental Protection Agency's (US EPA) guidance for evaluating potential health threats associated with contaminated fish recommends that a minimum of two target species be sampled including one predatory and one bottom feeding species. Target species are chosen to meet the following criteria: (1) known to accumulate high concentrations of target contaminants in their tissues; (2) normally populate the freshwater system being studied; (3) are routinely caught and consumed by anglers; (4) nonmigratory; (5) pollutant-tolerant; (6) easily identified; (7) abundant and easy to collect and (8) of sufficient size to provide adequate tissue samples for analyses of contaminants (US EPA, 2000). The analytical results of these fish tissue samples appear to indicate that toxic equivalency quotients concentrations of dioxins/furans have slightly decreased since 1988. In contrast, fish tissue levels of methyl mercury appear to have increased slightly since 1988. Dioxins/furans and methyl mercury levels detected in fish tissue samples caught in the Penobscot river located near Lincoln, Maine, may continue to pose a public health hazard to persons who consume the fish daily, depending on the amount consumed. The ATSDR concurred with Maine BOH's fish advisory for dioxins/furans and methyl mercury, that is, currently in place for portions of the Penobscot river near Lincoln. Toxicology and Industrial Health 2007; 23: 147—153.

Coal workers' pneumoconiosis (CWP) is an occupational pulmonary disease that occurs by chronic inhalation of coal dust. Coal workers' pneumoconiosis is divided into two categories depending on the extent of the disease as simple pneumoconiosis (SP) and progressive massive fibrosis (PMF). Development of CWP is associated with the activation of the immune system. Neopterin is a predictive biochemical marker of cell-mediated immune activation and elevated levels of neopterin are detected in body fluids of patients with immune-related diseases. The present study was aimed to investigate whether increased serum, urine and bronchoalveolar lavage (BAL) fluid levels of neopterin is associated with the development and/or severity of CWP. Mean serum neopterin levels in SP and PMF patients (10.72 ± 0.98 nmol/L; 14.08 ± 3.86 nmol/L, respectively) were significantly higher than those of control group (5.30 ± 0.47nmol/L) (P < 0.05). Although urinary neopterin levels were also increased in SP and PMF patients (235.17 ± 7.40 μmol/mol creatinine; 256.05 ± 9.43 μmol/mol creatinine, respectively) as compared with the control group (140.00 ± 5.43 μmol/mol creatinine) (P < 0.01), they were within the normal concentration range. No significant difference was observed between serum and urinary neopterin levels of SP and PMF patients. A correlation was observed between serum and urinary neopterin levels of all subjects (r = 0.525, P < 0.01). Bronchoalveolar lavage fluid neopterin levels were significantly higher in patients with SP and PMF (22.67 ± 2.9 nmol/L; 41.67 ± 8.68nmol/L, respectively) compared with control subjects (6.264 ± 1.74 nmol/L) (P < 0.05, P < 0.01, respectively). The levels of neopterin in BAL fluid were also significantly higher in patients with PMF than in those with SP ( P < 0.05). These findings indicate that elevated serum and BAL levels of neopterin may be considered as a suitable biomarker for the assessment of CWP. Toxicology and Industrial Health 2007; 23: 155—160.

Lead, cadmium, nickel and other industrial metals used as part of paint varnishes have been reported to have adverse health implications. An evaluation study on some toxicological effects of occupational exposure to paint, among 25 occupationally exposed artisans and 25 students (control) of Ichi Technical College, Ichi Ekwusigo Local Government Area, Anambra State, Nigeria was carried out. Heavy metals were analysed by atomic absorption spectrophotometry and standard assay procedures were employed for biochemical parameters. The biochemical indices used include serum electrolytes urea, creatinine, alanine (ALT) and aspartate aminotransferases (AST), alkaline phosphatase (ALP), conjugated and total bilirubin. Others include blood lead, serum cadmium and nickel. Our results showed that occupational exposure of humans to paints increased the blood lead (39 ± 4 μg/dL), serum cadmium (13 ± 1 μg/dL) and nickel (63 ± 1 μg/dL), when compared with non-paint factory workers (PFW) lead (17 ± 4 μg/dL), serum cadmium (9 ± μg/dL) and nickel (25 ± 44 μg/dL), significantly at P < 0.05 lower values were observed for serum sodium (138.96 ± 0.58mmol/L), bicarbonate (26.88 ± 0.39 mmol/L), urea (3.15 ± 0.13 mmol/L) and creatinine (80.48 ± 1.04 μmol/L) for paints factory workers when compared with non-paint factory workers, sodium (139.84 ±0.62mmol/L), bicarbonate (26.20 ±0.22mmol/L), urea (3.44 ± 0.11 mmol/L) and creatinine (80.40 ± 1.55 μmol/L); at P > 0.05. The activities of AST (10.36 ± 0.58 μ/L), ALT(8.76 ± 0.47 μ/L) and ALP (47.12 ± 3.33 μ/L) in PFW were slightly elevated compared with non-PFW. Our result indicates that occupational exposure of humans to heavy metals in paints may have long term deleterious effects on liver and renal functions. In conclusion, it should be noted that occupational exposure to cadmium or lead among PFW, may compromise the liver and renal functions in man. Toxicology and Industrial Health 2007; 23: 161—165.

Benzene exposure from vehicular sources and its health impact are relatively unexplored in India. We have investigated in this study hematology and lymphocyte subsets of 25 petrol pump attendants, 25 automobile service station workers and 35 controls matched for age, sex and socioeconomic conditions. The participants were non-smoking males of Kolkata (former Calcutta) in eastern India. Compared with controls, the workers had 3.8- times more trans,trans-muconic acid in urine, suggesting higher level of benzene exposure. The exposed subjects had decreased erythrocyte, hemoglobin, lymphocyte and platelet levels, but increased neutrophil, band cells, RBC aniso-poikilocytosis and target cells. In addition, CD4+, CD8+ and CD19+ cells were decreased by 37, 20 and 47% respectively, but CD 16+ 56+ NK cells were increased by 20%. P-selectin expression on platelet surface of the workers was significantly elevated (P < 0.05), indicating upregulation of platelet activity. In summary, the study revealed high level of benzene exposure from vehicular sources in India, and the exposed subjects had hematological and immunological alterations. Toxicology and Industrial Health 2007; 23: 167—175.