Styrene-oxide N-terminal valine haemoglobin adducts as biomarkers of occupational exposure to styrene.

Styrene is widely used in the production of various plastics, synthetic rubber and resins. Occupational exposure occurs mainly via inhalation and relatively high exposure occurs due to its use in manual application techniques. The aim of this study was to evaluate if SO-Hb adducts are a suitable biomarker for assessing occupational exposure to styrene. Seventy-five reinforced plastic workers and 77 control subjects were studied. In the selected population the main urinary styrene metabolites and the styrene oxide N-terminal valine (SO-Hb) adducts in human globin were quantified. The levels of SO-Hb adducts were significantly higher (p<0.01) in the exposed subjects (5.98pmol/g globin) when compared with controls (2.59pmol/g globin) and a significant difference was found in levels of SO-Hb adducts between non-smokers and smokers among the control group. From our data we conclude that SO-Hb adduct measurement is a sensitive and specific means of assessing exposure to styrene at the occupational and environmental level.

Reduced fertility among shoe manufacturing workers.

OBJECTIVES: To investigate whether fertility is reduced among female shoe manufacturing workers exposed to organic solvents. METHODS: A retrospective study was conducted on time to pregnancy (TTP) among 250 Portuguese shoe manufacturing workers exposed to solvents and 250 unexposed women working in stores of food units and storehouses. Data on TTP and related factors were collected by face-to-face interviews. The participation rate was 92%, and 81% of the workers (197 exposed women and 209 unexposed women) provided data for the analyses. Exposure assessment was based on hygienic measurements in the workplaces. TTP data were analysed with discrete proportional hazards regression. RESULTS: Female exposure to solvents was associated with reduced fertility (adjusted fecundability density ratio (FDR) 0.55, CI 0.40 to 0.74 for low exposure, and FDR 0.70, CI 0.52 to 0.94 for high exposure). The findings were robust in different sensitivity analyses. A slightly stronger association was found among women with regular menstrual cycles. Exposure for less than 6 years was more strongly associated with reduced fertility (FDR 0.50, CI 0.30 to 0.83 and FDR 0.50, CI 0.28 to 0.90 for low and high exposure, respectively) than at least 6 years of exposure (FDR 0.60, CI 0.39 to 0.92 and FDR 0.86, CI 0.57 to 1.29 for low and high exposure, respectively). There was an interaction between solvent exposure and female smoking or use of coffee, the exposed women who smoke or use coffee being highly fecund. CONCLUSIONS: The findings provide further evidence that exposure to organic solvents is hazardous for female reproduction. The observed association may be related to any of the following solvents commonly used in shoe manufacturing: n-hexane and hexane isomers, toluene, methyl ethyl ketone, acetone, ethyl acetate and dichloromethane.

Styrene-oxide N-terminal valine haemoglobin adducts in reinforced plastic workers: possible influence of genetic polymorphism of drug-metabolising enzymes.

Styrene is one of the most important organic chemicals used worldwide. In humans, styrene metabolism involves oxidation by cytochrome P450 monooxygenases (CYPs) to styrene-7,8-oxide, an epoxide thought to be responsible for the genotoxic effects of styrene exposure, and detoxification by means of epoxide hydrolase (mEH) and glutathione S-transferases (GSTs). The objective of this study was to investigate if genetic polymorphisms of metabolic enzymes modulate the level of urinary styrene metabolites and styrene oxide adducts with N-terminal valine of human globin (SO-Hb) in 75 workers occupationally exposed to styrene and 77 unexposed controls. The mean air concentration of styrene in the breathing zone of workers (30.4ppm) was higher than the threshold limit value of 20ppm recommended by the American Conference of Governmental Industrial Hygienists (ACGIH), and the biological exposure index adopted by the ACGIH for exposure to styrene prior to the next shift (MA+PGA=400mg/g creatinine) was exceeded, indicating that styrene exposure for this group of workers was higher than recommended. A highly significant correlation was observed between styrene concentration in the breathing zone and the MA+PGA in urine of workers (r=0.85, P<0.001). The levels of SO-Hb adducts in exposed workers were significantly increased as compared with controls, although no difference was observed between subjects stratified as high and medium exposure categories based on MA+PGA excretion. Regarding the effect of the genetic polymorphisms we found that the level of SO-Hb adducts might be modulated by the predicted mEH enzymatic activity in the exposed workers. From our data we conclude that SO-Hb adduct measurement is a complementary method to MA+PG measurement for assessing exposure to styrene at occupational and environmental levels, which reflects a more extensive exposure period.

Health impact of living near an abandoned mine--case study: Jales mines.

The activities of mining exploitation in Campo de Jales were performed in an uncontrolled way and gave rise to serious environmental contamination: rubbish depositories have been accumulated with no treatment or maintenance. An investigation developed around Jales Mine showed the existence of some chemical impact originated from the waste produced during mining activities. Some "black spots" for a wide suite of heavy metals were determined in stream sediments and alluvium drained from Jales tailings, which could constitute hazard factors for the area and potential danger for public health. The main objective of this study is to know the effects on health caused by this environmental contamination. It is a case-control study, where two populations--from Campo de Jales and Vilar de Maçada--were compared. They both have very similar living conditions, and were inquired about health issues and screening for lead and cadmium exposure. The results point out to higher prevalence of irritating symptomatology in the mucous of the eyes and respiratory system as well as higher lead and cadmium exposure in the Campo de Jales population.

Lead exposure of children and newborns in Porto, Portugal.

Lead is a naturally occurring element that has multipurpose applications and has been used since early civilizations being widespread in the environment. Lead is not biodegradable and its continual use has contaminated air, water, and soil. It is highly toxic affecting the whole body and is particularly harmful to newborns and children, adversely affecting cognitive development and behaviour. For children aged <6 years the Centres for Disease Control and Prevention (CDC), in 1991, defined an elevated blood lead level (BLL) as >or= 10 microg/dl, but evidence exists for subtle effects at lower levels. From the 1980s, the international trend has been to phase-out lead content in gasoline, which has contributed to substantially lower average BLLs in these populations. However, its complete elimination from gasoline in Portugal was not reached before 1999. Our group has from long participated in BLL surveillance programs to help target prevention efforts and monitor progress toward reducing BLLs in Portugal. Here are presented the studies carried out with children.

Genotoxic effects in a population of nurses handling antineoplastic drugs, and relationship with genetic polymorphisms in DNA repair enzymes.

BACKGROUND: Concern about the genotoxic risk associated with chronic handling of antineoplastic drugs has increased, and usual safety practices may not avoid exposure. METHODS: Comet assay and MN test were performed on 30 oncology nurses and 22 controls. Genetic polymorphisms of XRCC1, XRCC3, and APE1 genes were determined by PCR-RFLP. RESULTS: Data obtained showed increased cytogenetic and DNA damage in the exposed group, although statistical significance was only reached in the comet assay. Significant differences in TL were observed for carriers of the variant alleles of every gene analyzed. However, no significant effect was detected in the MN test. CONCLUSIONS: Evidence that the present handling practices of antineoplastic drugs in some Portuguese hospitals are not enough to prevent exposure are provided. Present data suggest that genetic polymorphisms in the studied DNA repair enzymes may influence the individual susceptibility to DNA damage related to chronic handling of antineoplastic drugs.

Childhood lead exposure in Oporto, Portugal.

The study aims were to evaluate childhood lead poisoning in Oporto, Portugal, characterize childhood exposures, find solutions to reduce them, and call the community's attention to the need for preventive measures. Children aged 1-5 years living in Oporto Historical Center, were the target population. Data were gathered by means of a questionnaire and blood lead analyses for 240 children who attended four randomly selected kindergartens. The geometric mean blood lead concentration was 13.9 microg/dl and lead poisoning prevalence (blood lead levels > 10 microg/dL) was 85.8%. Important sources of lead poisoning were father's occupation, mother's smoking habits, and poor hygiene and pica associated with contaminated soils and lead paint. Families were unaware of the problem of lead exposure and its harmful effects. The data indicate that high levels of childhood lead exposures still prevail in Oporto City, an important public health finding that deserves authorities' attention.

Biological monitoring of n-hexane exposure in Portuguese shoe manufacturing workers.

Occupational risk of exposure to organic solvents concerned many shoe manufacturing workers. The most common organic solvents found in workplace environments were n-hexane and others hexane isomers. The aim of this study was to evaluate the exposure of shoe manufacturing workers to n-hexane, with 2,5 hexanedione in urine (2,5HD) as a biomarker and to investigate effect in 2,5 HD excretion of the co-exposure to other organic solvents. Post-shift urine samples from workers who performed gluing tasks (n = 45) in five shoe manufacturers were collected, as well as urine samples from a similar number of unexposed controls (n = 51) in the same factories. 2,5 HD was measured by capillary gas chromatography. Air monitoring of organic solvents in the workplaces was performed and the compounds were analyzed by gas chromatography. Significant more 2,5 HD was found in the urine of personnel who performed gluing tasks than in the unexposed workers. A significant correlation was observed between n-hexane exposure and urinary 2,5 HD, with a high correlation coefficient. Multiple regression analysis indicated that n-hexane exposure and co-exposure to others solvents were significant predictors of the concentration of 2,5 HD. Co-exposure led to higher urinary 2,5 HD concentrations. The significant effect of co-exposure reinforces the interest of biological monitoring for n-hexane exposure evaluation. In case of multiple exposures, biological monitoring can be a better predictive measurement for early detection of n-hexane neurotoxic lesions than air monitoring data.

Shoe manufacturing and solvent exposure in northern Portugal.

Shoe manufacturing is a traditional industry in northern Portugal. There are nearly 1500 factories that employ about 54,000 workers. Among the materials used in the shoe manufacturing process, that could be occupational hazards, are the adhesives, especially adhesives solutions based on organic solvents. The National Institute of Health (Oporto Branch) carried out a study of 100 factories in northern Portugal to study solvent exposure in shoe manufacturing. The surveyed population, (4615 workers) was young (mean age = 33 years; range = 18-45) and predominantly female (68.5%). The results from the air samples analyses show 20 different organic compounds existing in the workplaces. The more common compounds found were n-hexane, toluene, and acetone. The results of the study show that in 53.7 percent of the factories there are operations where the solvent exposure is significant and represents a health hazard to the workers. These operations are mainly gluing, waxing, and polishing stations. Occupational risk of exposure to solvents concerned 44.2 percent of the workers. This study points out the existence of inadequate ventilation in the workplaces and inappropriate personal protective equipment to prevent dermatitis risk from adhesives, wax, and polish. The organic solvents present in workplaces also increase fire risk.

[Prevalence of respiratory diseases in the textile industry. Relation with dust levels]. / Prevalência de doença respiratória na indústria têxtil. Relação com os níveis de empoeiramento.

Many workers in the textile industry have respiratory symptoms that are related to their work environment. In this study we observed the dust level conditions of eleven textile industries of the North of Portugal. The dust levels determined were between 0.1 mg/m3 and 1.25 mg/m3, in many cases above the Portuguese standard levels of exposure (VLE). For these dust levels we found a prevalence of 23% of workers with respiratory symptoms with occupational characteristics in 10.8%, and 5.7% presenting byssinosis. Workers exposed to cotton fibres in spinning areas have the highest prevalence of symptoms, and reduction of the FEV1. These characteristics were related to dust levels and were higher in the initial phases of the spinning processes. We found no cases of byssinosis in workers exposed to synthetic fibres, or in workers from weaving areas. Smoking habits were related to the reduction of the FEV1, and severity of respiratory illness but not to the presence of byssinosis.

[Respiratory symptoms in the textile industry. Their prevalence in the Vale do Ave]. / Sintomas respiratórios na indústria têxtil. Prevalência no Vale do Ave.

Some workers in the textile industry have respiratory symptoms related to their occupation. This study is aimed at evaluating the frequency of respiratory symptoms in textile industries in the North of Portugal. We evaluated 3529 workers from 20 factories (19 deal with synthetic fibres and cotton and the other deals with sisal.) Among the workers, there were 34.5% with respiratory symptoms - 24,5% referred nasal symptoms, 22,6% with bronchial symptoms and 12,6% associated both. The workers who dealt with cotton presented a higher frequency of bronchial symptoms (25,0%) than the ones dealing with synthetic fibres (12,7% p < 0,000001). The same was noticed among the workers in the opening and spinning areas, who showed a higher frequency of bronchial symptoms (28,3%) than the ones in weaving areas (12,7% p < 0,000001). We did not find any differences concerning the frequency of symptoms among the workers handling both natural fibres (cotton and sisal). Individually all the symptoms were more frequent among the workers handling natural fibres. The most frequent symptom depended on the fibre. Cough was more frequently mentioned among the workers handling synthetic fibres (9.6%) and cotton (15.7%). Among the workers who handle sisal, dyspnea was the most frequently mentioned (16.9%). Productive cough was the most frequent association (7.2% sisal; 2.8% synthetic; 8.0% cotton), and the association between dyspnea and wheezing the least mentioned (6.4% sisal; 0.5% synthetic; 5.9% cotton). The workers with bronchial symptoms (synthetic fibre and cotton) have more years of exposure and greater smoking habits. In a covariance adjusted for age and smoking habits, the workers with bronchial symptoms, exposed to cotton have more years of exposure.

[Children and lead exposure. Preliminary study]. / A criança e a exposição a chumbo. Inquérito preliminar.

UNLABELLED: Lead poisoning is one of the most common and preventable childhood illness. The authors believe that the present study is the first evaluation of this problem in Portugal. OBJECTIVES: a) to characterize blood lead levels in children aged 1 to 6 years living in the Oporto area; b) to identify risk groups and develop screening strategies. MATERIAL AND METHODS: The authors studied an opportunistic sample of children that were observed at the Hospital Maria Pia and the Instituto Nacional de Saúde Dr. Ricardo Jorge (Porto) to whom blood testing was requested. All children with neurological or digestive symptoms were excluded (October-December 1991; n = 113). RESULTS: One child had a blood lead level of 46.6 micrograms/dl (class-IV, CDC); 32% (n = 36) were between 20 e 44 micrograms/dl (class-III), while only four children (3.2%) presented values < = 9 micrograms/dl (class-I). Class II included the remainder (n = 73). The results clearly point out that lead poisoning is a real problem among Portuguese children, since the proportion of children not considered to be lead-poisoned is very small. Children in the other classes are at risk of developing acute and chronic toxicity.