Biological monitoring of metals and organic substances in hazardous-waste incineration workers

Serum levels of PCDDs, PCDFs and dl-PCBs in general population residing far and near from an urban waste treatment plant under construction in Gipuzkoa, Basque Country (Spain)

This research focused on investigating the basal serum concentrations of polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in the general population residing in two urban-industrial zones near and far from an energy recovery plant under construction in Gipuzkoa, Basque Country (Spain). The study used a cross-sectional design and included 227 participants who were randomly selected from municipal censuses in both areas. The participants were stratified based on age (ranging from 18 to 70 years) and sex. Serum samples were collected from the participants and analysed following the established protocol to measure the concentrations of PCDD/Fs and dl-PCBs. The study used multiple linear regression models to assess the impact of various sociodemographic variables, lifestyle factors, reproductive history, and diet on the variability of the measured compounds in the participants' serum. The median total toxicity equivalent (TEQ) in serum, was 10.58 pg WHO-TEQ2005 g-1 lipid. Serum PCDD levels were lower in the population residing in the "far" zone than the "near" zone. Age was positively associated with both PCDD/F and dl-PCB levels, indicating that older participants had higher concentrations of these compounds in their serum. This finding might be attributed to cumulative exposure over time. In terms of sex differences, women exhibited lower levels of dl-PCBs compared to men. Among lifestyle factors, smokers showed lower levels of dl-PCBs compared to non-smokers. Furthermore, daily alcohol consumption was significantly associated with higher serum levels of these compounds, with daily drinkers showing higher levels than non-drinkers. Consumption of local poultry was associated with significantly higher serum levels and oil consumption with low levels of PCDD/Fs.

Occupational Exposure to Hexavalent Chromium, Nickel and PAHs: A Mixtures Risk Assessment Approach Based on Literature Exposure Data from European Countries

Hexavalent chromium (Cr(VI)), nickel (Ni) and polycyclic aromatic hydrocarbons (PAHs) are genotoxic co-occurring lung carcinogens whose occupational health risk is still understudied. This study, conducted within the European Human Biomonitoring Initiative (HBM4EU), aimed at performing a mixtures risk assessment (MRA) based on published human biomonitoring (HBM) data from Cr(VI), Ni and/or PAHs occupational co-exposure in Europe. After data extraction, Risk Quotient (RQ) and Sum of Risk Quotients (SRQ) were calculated for binary and ternary mixtures to characterise the risk. Most selected articles measured urinary levels of Cr and Ni and a SRQ > 1 was obtained for co-exposure levels in welding activities, showing that there is concern regarding co-exposure to these substances. Similarly, co-exposure to mixtures of Cr(VI), Ni and PAHs in waste incineration settings resulted in SRQ > 1. In some studies, a low risk was estimated based on the single substances’ exposure level (RQ < 1), but the mixture was considered of concern (SRQ > 1), highlighting the relevance of considering exposure to the mixture rather than to its single components. Overall, this study points out the need of using a MRA based on HBM data as a more realistic approach to assess and manage the risk at the workplace, in order to protect workers’ health.

Levels and determinants of urinary cadmium in general population in Spain: Metal-MCC-Spain study

BACKGROUND

Cadmium is a ubiquitous and persistent metal, associated with different harmful health effects and with increased morbidity and mortality. Understanding the main sources of exposure is essential to identify at risk populations and to design public health interventions.

OBJECTIVE

To evaluate cadmium exposure in a random-sample of general adult population from three regions of Spain, assessed by the urinary cadmium (U-Cd) concentration, and to identify its potential determinants and sex-specific differences, including sociodemographic, lifestyle and dietary factors.

MATERIALS AND METHODS

We measured U-Cd (μg/g creatinine) in single urine spot samples from 1282 controls enrolled in the multicase-control study in common tumors in Spain (MCC-Spain) with inductively coupling plasma-mass spectrometry equipped with an octopole reaction systems (ICP-ORS-MS). The association between sociodemographic, lifestyle, and dietary characteristics and U-Cd concentrations was evaluated using geometric mean ratios (GMR) estimated by multiple log-linear regression models.

RESULTS

Overall, geometric mean U-Cd concentration was 0.40 (95%CI: 0.38, 0.41) μg/g creatinine. Levels were higher in women than in men (GMR]: 1.19; 95%CI: 1.07, 1.32), and increased with age in males (p_trend< 0.001). Cigarette smoking was clearly associated to U-Cd levels (GMR_{former vs non-smokers}: 1.16; 95%CI: 1.05, 1.29; GMR_{current vs non-smokers}: 1.42; 95%CI: 1.26, 1.60); the relationship with secondhand tobacco exposure in non-smokers, was restricted to women (p_interaction = 0.02). Sampling season and region also seemed to influence U-Cd concentrations, with lower levels in summer (GMR_{summer vs average}: 0.79; 95%CI: 0.71, 0.88), and higher levels in North-Spain Asturias (GMR_{Asturias vs average}: 1.13; 95%CI: 1.04, 1.23). Regarding diet, higher U-Cd concentration was associated with eggs consumption only in men (p_interaction = 0.04), just as rice intake was associated in women (p_interaction = 0.03).

CONCLUSION

These results confirmed that tobacco exposure is the main modifiable predictor of U-Cd concentrations, and remark that the role of dietary/sociodemographic factors on U-Cd levels may differ by sex.

Destruction of dioxin and furan pollutants via electrophilic attack of singlet oxygen

Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) remain of particular concern owing to their extensive toxicity towards health and accumulation in the environment. Atmospheric oxidation (by ambient oxygen molecules) of this class of persistent environmental pollutants has little to no kinetic feasibility due to very sizable activation energies in the entrance channel. The current control measures involve energy-intensive source incineration of contaminated materials at high temperatures as high as 850 °C. This study finds an alternative low-energy approach of destroying dioxin-like compounds, proposing that advanced oxidation by highly reactive singlet oxygen (O₂¹Δ_g, originated from chemical, surface-mediated and photochemical processes) can initiate low-temperature remediation of these pollutants. This contribution completes the first milestone in mapping out the mechanisms of the electrophilic addition of singlet oxygen to unsubstituted and chlorinated dibenzo-p-dioxin (DBD) and dibenzofuran (DBF) structures, according to density functional theory DFT-B3LYP method in conjunction with the 6-311+g(d,p) basis set, as well as energy refinements based on the approximate spin-projection scheme. The [2+2]-cycloaddition mechanism appears dominant for singlet oxidation of dibenzo-p-dioxin with a fitted rate constant of k(T) = 5.01 × 10^-14 exp(-98000/RT). On the other hand, the addition of singlet oxygen to the aromatic ring of dibenzofuran primarily transpires via [4+2]-cycloaddition channel with a fitted rate constant of k(T) = 2.16 × 10^-13 exp(-119000/RT). The results suggest that application of singlet oxygen can reduce the energy cost of recycling halogenated and flame retarded materials.

Concentrations of PCDD/Fs in Human Blood: A Review of Data from the Current Decade

Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo-p-furans (PCDD/Fs) are environmental pollutants with great persistence, the capacity of bioaccumulation, and well known important toxic effects in humans and animals. Incinerators of hazardous, municipal and medical waste, chlorine bleaching of paper pulp, cement plants, and the traffic of motor vehicles are the most frequent emission sources of these compounds. The diet, followed at a great distance by inhalation, is generally the main way of human exposure to PCDD/Fs. Human biomonitoring is of great importance to prevent potential adverse effects derived from exposure to chemicals such as PCDD/Fs. In relation to this, blood is among the most used biological monitors. In the current review, we have summarized the recent information (2000–2009) published in the scientific literature (databases: Scopus and PubMed) on the concentrations of PCDD/Fs in blood samples of non-occupationally exposed populations, as well as in some groups of occupationally exposed individuals. We have revised a number of studies conducted in various African, American, Asian and European countries, and Australia. Unfortunately, the information is quite limited. No data are available for most countries over the world. Based on the results here reviewed, where available, the current health risks for the general populations do not seem to be of concern. Moreover, taking into account the important reductions observed in the levels of PCDD/Fs in foodstuffs, new decreases in the concentrations of PCDD/Fs in blood—and other biological tissues—are very probable in the immediate years.

Monitoring dioxins and furans in plasma of individuals living near a hazardous waste incinerator: Temporal trend after 20 years

The concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were analyzed in 40 plasma samples of individuals living in zones under potential influence of the emissions of a hazardous waste incinerator (HWI) (Tarragona County, Catalonia, Spain). Samples corresponded to subjects of different gender, age and specific areas of residence. The levels of PCDD/Fs were compared to those obtained in a baseline study (1998), as well as in previous surveys (2002, 2007 and 2012). The current mean concentration of PCDD/Fs in plasma was 6.79 pg I-TEQ/g lipid, which was significantly lower than the baseline concentration (27.0 pg I-TEQ/g lipid). A significant decrease was also observed in comparison to the results obtained in 2002 and 2007 (15.7 and 9.4 pg I-TEQ/g, respectively), while the current PCDD/F levels were similar to those obtained in 2012 (6.18 pg I-TEQ/g lipid). This important reduction in plasma PCDD/F levels is in accordance with the decreasing trend in the daily dietary intake of PCDD/Fs, which diminished from 210.1 pg I-TEQ (baseline) to 8.54 pg WHO-TEQ (current). OCDD was the predominant congener in plasma, while 2,3,7,8-TeCDD and 1,2,3,4,7,8,9-HpCDF showed the lowest levels. Based on the above results, as well as other recent data on the levels of PCDD/Fs in human milk, we conclude that the presence of the HWI does not mean additional and significant risks -as regards to PCDD/F exposure-for the population living in the neighborhood of the facility.

Systematic Review: Occupational illness in the waste and recycling sector

BACKGROUND

The waste and recycling sector is a growing part of industry. Whether health surveillance is indicated and how it should be undertaken is unclear.

AIMS

To undertake a review of the literature to identify hazards to health, biological effects and occupational illnesses for workers in the sector.

METHODS

A systematic review of the published literature and two UK databases.

RESULTS

Rates of fatal, non-fatal injuries and self-reported work-related illness were found to be higher in the waste and recycling sector than in UK industry as a whole. There was an increased prevalence of respiratory, gastro-intestinal and skin complaints in workers exposed to compost relative to controls. They may also be at increased risk of extrinsic allergic alveolitis, allergic bronchopulmonary aspergillosis, occupational asthma and abnormalities of lung function. Workers involved with the recycling of batteries and cables may be at risk of lead poisoning and exposure to other heavy metals. There were case reports of mercury poisoning from the recycling of fluorescent lights. Cases of occupational asthma have been reported in association with wood and paper recycling. The recycling of e-waste may cause exposure to heavy metals and organic pollutants, such as polybrominated diphenyl ethers, dioxins and polyaromatic hydrocarbons, which have been associated with damage to DNA and adverse neonatal outcomes.

CONCLUSIONS

Ill-health and adverse biological effects have been described in waste and recycling workers, but their true prevalence has probably not been captured. Targeted health surveillance may be required to assess exposure and to identify occupational illness.

Human biomonitoring of polycyclic aromatic hydrocarbonsand metals in the general population residing near the municipal solid waste incinerator of Modena, Italy

BACKGROUND AND OBJECTIVES

A cross-sectional biomonitoring study was carried out to investigate exposure to incinerator emission in relation to the body burden of selected biomarkers in the population living around the plant.

METHODS

Approximately 500 people, aged 18-69 yrs, living within 4 km from the incinerator were randomly selected form the population register. Exposure was measured through fall-out maps of particulate matter (PM), used as tracer for incinerator emissions. Ten metabolized polycyclic aromatic hydrocarbons (PAHs), from naphthalene to chrysene, 1-hydroxypyrene and twelve metals (Cd, Cr, Cu, Hg, Ni, Pb, Ni, Zn, V, Tl, As, Sn) were measured in spot urine samples. Confounders, such as diet, smoking, traffic, occupation and personal characteristics were assessed by questionnaires and objective measurements, and included into multivariate linear regression models.

RESULTS

Metal concentrations in urine were in line with or higher than Italian reference limits, besides Cr and V with more than twofold concentrations. Metal levels did not show clear association to exposure categories. Most abundant PAHs were naphthalene (median 26.2 ng/L) and phenanthrene (7.4 ng/L). All PAHs, but benz[a]anthracene and 1-hydroxypyrene, were found in more than 52% of samples, and included in regression models. Significant associations between urinary PAHs and exposure were found, strong for fluorene, and weaker for naphthalene, fluoranthene and pyrene. Results were confirmed by sensitivity analyses. Correlation with variables reported in literature were observed.

CONCLUSIONS

The study indicates that the emissions were very low and highlights that specific urinary PAHs provided useful information about the internal dose arising from incinerator emission.

Biomonitoring of toxic metals in incinerator workers: A systematic review

Exposure to chemicals released during urban waste disposal and treatment is increasingly regarded as a potential occupational health issue. Indeed, several toxic metals emitted by an incinerator, including As, Be, Cd, Cr, Pb, Mn, Hg, Ni and V, have potentially toxic properties and their exposure, therefore, may be of concern for the health of the workers involved. The levels of exposure should therefore be carefully measured. Environmental monitoring, however, may be unable, alone, to assess true exposure, due to its intrinsic limitations mainly concerning its inability to assess oral and dermal absorption. In these cases biological monitoring may represent a fundamental supplementary tool for the definition of the workers' true occupational exposure and for the prevention of the related health effects. There is, therefore, an increasing interest in developing and using, in these workers, sensitive and specific biomarkers for health risk assessment, particularly at low or even very low levels of exposure. Despite the large number of original and review articles present in the literature on the biomonitoring of workers exposed to metals, the data on subjects employed in waste treatment activities are scattered and results are sometimes inconsistent. This is the first systematic review, performed according to PRISMA methodology, of the major studies investigating the levels of different toxic metals measured in the main biological matrices (blood, urine, hair) of incinerator workers. The results show that the levels of metals measured in incinerators' workers are generally low, with some notable exceptions for Cd and Pb. These results, though, can be affected by several confounders related either to non-occupational exposure, including diet, area of residence and others, and/or by a number of methodological limitations, as we found in the reported studies. Future work should focus on an integrated approach, using ideally both biological and environmental monitoring. A particular emphasis should be given to the measurement of the different granulometric fractions of the dust containing metals, i.e. inhalable, thoracic, respirable and ultrafine fractions. Moreover, an accurate description of the work tasks and the characteristics and levels of non-occupational exposure should always be provided.

Mercury risk assessment combining internal and external exposure methods for a population living near a municipal solid waste incinerator

Risk assessments for human health have been conducted for municipal solid waste incinerators (MSWIs) in many western countries, whereas only a few risk assessments have been performed for MSWIs in developing countries such as China where the use of waste incineration is increasing rapidly. To assess the mercury exposure risks of a population living near the largest MSWI in South China, we combined internal exposure and external exposure assessment with an individual-specific questionnaire. The mercury concentrations in air, soil, and locally collected food around the MSWI were assessed. The total mercury (T-Hg) and methylmercury (MeHg) of 447 blood samples from a control group, residential exposure group, and MSWI workers were measured. The internal and external exposures of the subject population were analyzed. Significant difference in MeHg concentrations was observed between the control group and the exposed group, between the control group and the MSWI workers, and between the exposed group and the MSWI workers (median levels: 0.70 μg/L, 0.81 μg/L, and 1.02 μg/L for the control group, exposed group, and MSWI workers, respectively). The MeHg/T-Hg ratio was 0.51 ± 0.19, 0.59 ± 0.17 and 0.58 ± 0.25, respectively. Multiple linear regression analysis indicated that MeHg concentrations were positively correlated with the gaseous mercury in the air. Combining internal and external exposure assessment showed that the direct contribution of MSWI emissions was minor compared with the dietary contribution. The external and internal exposures were well matched with each other. This study also suggested that an integrated method combining internal and external exposure assessment with an individual-specific questionnaire is feasible to assess the risks for a population living near a MSWI.

Cadmium levels in a representative sample of the Spanish adult population: The BIOAMBIENT.ES project

Urinary cadmium levels (U-Cd) were measured in 1770 adults (aged 18-65 years) as a representative sample of the Spanish workforce. The geometric mean (GM) was 0.28 μg/l with 95% CI: 0.27-0.32 μg/l (GM: 0.20 μg/g 95% CI: 0.18-022 μg/g creatinine). The 95% percentile was 1.03 μg/l. U-Cd increased with age, with women showing higher U-Cd than men (p<0.001; 0.24 μg/g vs 0.17 μg/g). A multivariate analysis confirmed that sex, age and smoking habit significantly influence U-Cd. Smoking habit increases U-Cd by ∼90% per 10 years of age, almost twice the increase observed for non-smoking. Female smokers had 85% higher U-Cd than non-smokers, whereas the corresponding value for male smokers and non-smokers was 45%. No regional differences were observed with respect to the national reference level. The Spanish population studied here exhibits similar urinary cadmium levels to its European counterparts in Germany and slightly lower levels than in France, the Czech Republic, Italy and the United Kingdom. This paper provides the first baseline information concerning cadmium exposure in the Spanish adult population on a national scale. As such, these findings will help us to establish reference levels, follow temporal trends and identify high-exposure groups, thereby enabling comparisons with other countries and contributing to the improvement of public health and environmental quality.

Levels of PCDD/Fs, PCBs and PBDEs in breast milk of women living in the vicinity of a hazardous waste incinerator: assessment of the temporal trend

The concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) were determined in breast milk from women living in the vicinity of a hazardous waste incinerator (HWI) in Catalonia, Spain. The results were compared with the levels obtained in previous surveys carried out in the same area in 1998 (baseline study), 2002 and 2007. The current total concentrations of 2,3,7,8-chlorinated PCDD/Fs in breast milk ranged from 18 to 126 pg g(-1)fat (1.1-12. 3 pg WHO2005-TEQPCDD/F), while the total levels of PCBs ranged from 27 to 405 pg g(-1)fat(0.7-5.3 pg WHO2005-TEQPCB). In turn, PBDE concentrations (sum of 15 congeners) ranged 0.3-5.1 g g(-1)fat, with a mean value of 1.3 ng g(-1)fat. A general decrease in the concentrations for PCDD/Fs, both planar and total PCBs, and PBDEs in breast milk was observed. The levels of PCDD/Fs, PCBs, and PBDEs in milk of women living in urban zones were higher than those corresponding to industrial zones (41%, 26%, and 8%, respectively). For PCDD/Fs and PCBs, the current decreases are in accordance with the reduction in the dietary intake of these pollutants that we have also observed in recent studies carried out in the same area of study.

Vanadium release in whole blood, serum and urine of patients implanted with a titanium alloy hip prosthesis

INTRODUCTION

Vanadium (V) is a minor constituent of the Titanium-Aluminum-Vanadium (TiAlV) alloy currently used in cementless hip prostheses. Present study aimed at verifying the correlation of vanadium levels among different matrices and assessing reference levels of the ion in a population of patients wearing a well-functioning hip prosthesis.

METHODS

Vanadium was measured using Inductive Coupled Plasma Mass Spectrometry (ICP-MS) in whole blood, serum and urine of 129 patients implanted with a TiAlV-alloy hip prosthesis.

RESULTS

The values in the serum were above the upper limit of the reference values in 42% of patients (29% in urine and 13% in whole blood). A good correlation among matrices was observed (p < 0.001). The cohort of patients (N = 32) complaining of pain or in which a loosening or damage to the prosthesis was assessed showed a significantly higher excretion of vanadium in urine as compared with the remaining asymptomatic patients (p = 0.001). The 95th percentile distribution of vanadium in the cohort of patients with a well-functioning prosthesis was 0.3 μg/L in whole blood, 0.5 μg/L in serum and 2.8 μg/L in urine, higher that in the unexposed population, especially for urine.

CONCLUSIONS

The presence of a prosthesis, even though well-functioning, may cause a possible release of vanadium into the blood and a significant urinary excretion. The reference values of vanadium of the asymptomatic patients with titanium alloy hip prostheses supplied information regarding the background exposure level of the ions and their lower and upper limits.

Body burden monitoring of dioxins and other organic substances in workers at a hazardous waste incinerator

The construction in Constantí (Tarragona County, Catalonia) of the first, and up till now the only hazardous waste incinerator (HWI) in Spain, finished in 1999. In this study, we measured the concentrations of a number of organic substances determined in blood and urine of the HWI workers. Samples of 18 men and 9 women, classified according to their respective workplaces, were collected in 2011, after approximately 12 years of regular operations in the facility. The current results were compared with those of the baseline survey, as well as with the most recent surveys performed in 2008, 2009 and 2010. Plasma analyses were carried out for hexachlorobenzene (HCB), polychlorinated biphenyls (PCBs 28, 52, 101, 138, 153, and 180) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), while the levels of 2,4- and 2,5-dichlorophenol (DCP), 2,4,5- and 2,4,6-trichlorophenol (TCP), pentachlorophenol (PCP) and 1-hydroxypyrene (1-HP) were measured in urine samples. In plasma, the mean concentrations were the following: 10.8μg/kg lipid for HCB; 0.8μg/kg lipid for PCB28; 0.3μg/kg lipid for PCB52; 0.5μg/kg lipid for PCB101; 42.2μg/kg lipid for PCB138; 18.5μg/kg lipid for PCB153, and 51.2μg/kg lipid for PCB180. For PCDD/Fs, the mean concentration was 4.6ng I-TEQ/kg lipid (4.7ng WHO-TEQ/kg lipid). These levels, as well as those found in urine samples, are in agreement with the data of previous surveys performed in the same area. The current results in HWI workers do not show any evident sign of occupational exposure to PCDD/Fs and other organic substances. However, these results must be considered only as an indication of potential exposure, as the study presents notable limitations, such as the reduced number of participants and the lack of data relative to the air concentrations of chemicals. Consequently, general conclusions cannot be derived and the results should not be used as a basis for the implementation of industrial hygiene measures in other HWIs.

Blood levels of dioxins, furans, dioxin-like PCBs, and TEQs in general populations: a review, 1989-2010

A comprehensive worldwide literature review of blood levels of dioxins and dioxin-like compounds in non-exposed adult general populations was performed. The studies published in 1989-2010 reporting information on polychlorinated dibenzo-para-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), non-ortho-PCBs (nPCBs), mono-ortho-PCBs (mPCBs) levels and Toxic Equivalencies (TEQs, a summary weighted measure of their combined toxicity) were reviewed. TEQs were calculated using as standard the most recent WHO 2005 reevaluation of Toxic Equivalency Factors (TEFs). Weighted multiple regression analyses adjusted for year, subject's age, type of sample analyzed, method used for values below detection limit, and central tendency measure used were performed for each congener and standardized TEQs (log-transformed). We identified 187 studies regarding 29,687 subjects of 26 countries. Year of blood collection ranged from 1985 to 2008. The studies reporting congener levels 161. In adjusted analyses, European countries showed higher levels of most dioxin-like congeners and TEQs. A strong positive association of subjects' age with most congeners and with TEQ values was found, confirming previous findings. Significant decreases over time (1985-2008) were documented for PCCDs, PCDFs, and TEQs including their contributions. No significant decrease was found for non-ortho-PCBs, notably PCB 126. Only some mono-ortho-PCBs showed clear significant declines. Accordingly, TEQs including only PCB contribution did not decrease over time. In interpreting these findings, it should be considered that for dioxin-like PCBs the analysis period was shorter (17 years), since these compounds were first measured in 1992.

PCDD/Fs and dioxin-like PCBs in human milk and estimation of infants' daily intake: a review

This paper reviews the recent scientific literature on PCDDs, PCDFs and dioxin-like PCBs in human milk. All the papers reporting levels of these contaminants in human breast milk published from January 2000 to January 2009 and available on the www.sciencedirect.com web site were identified and included. The aim was (1) to study levels of PCDDs, PCDFs and PCBs in human milk in mothers from different geographical areas and assess infant exposure to these contaminants; (2) to study the effect of variables such as the mother's age, number of deliveries, dietary and smoking habits and her own nutrition in infancy, and the environment, on levels of the contaminants in breast milk; (3) to study time patterns, and (4) to identify data gaps.

Blood Lactate Diagnostics in Exercise Testing and Training

A link between lactate and muscular exercise was seen already more than 200 years ago. The blood lactate concentration (BLC) is sensitive to changes in exercise intensity and duration. Multiple BLC threshold concepts define different points on the BLC power curve during various tests with increasing power (INCP). The INCP test results are affected by the increase in power over time. The maximal lactate steady state (MLSS) is measured during a series of prolonged constant power (CP) tests. It detects the highest aerobic power without metabolic energy from continuing net lactate production, which is usually sustainable for 30 to 60 min. BLC threshold and MLSS power are highly correlated with the maximum aerobic power and athletic endurance performance. The idea that training at threshold intensity is particularly effective has no evidence. Three BLC-orientated intensity domains have been established: (1) training up to an intensity at which the BLC clearly exceeds resting BLC, light- and moderate-intensity training focusing on active regeneration or high-volume endurance training (Intensity < Threshold); (2) heavy endurance training at work rates up to MLSS intensity (Threshold ≤ Intensity ≤ MLSS); and (3) severe exercise intensity training between MLSS and maximum oxygen uptake intensity mostly organized as interval and tempo work (Intensity > MLSS). High-performance endurance athletes combining very high training volume with high aerobic power dedicate 70 to 90% of their training to intensity domain 1 (Intensity < Threshold) in order to keep glycogen homeostasis within sustainable limits.

Biomonitorization of cadmium, chromium, manganese, nickel and lead in whole blood, urine, axillary hair and saliva in an occupationally exposed population

Heavy metal contamination from occupational origin is a cause for concern because of its potential accumulation in the environment and in living organisms leading to long term toxic effects. This study was aimed to assess Cd, Cr, Mn, Ni and Pb levels in whole blood, urine, axillary hair and saliva from 178 individuals with occupational exposure to heavy metals. Levels of metal compounds were determined by atomic absorption spectrometry. We collected information on occupation, lifestyle habits and food intake by questionnaire. Multiple linear regression analyses for metal ion concentration in whole blood, urine, axillary hair and saliva were adjusted for age, gender, smoking and alcohol consumption, lifetime workplace exposure, residence area and food habits. Overall, blood and urine median concentrations found for the five metals analyzed do not exceed biological exposure indexes, so that they are very similar to a non-occupationally exposed population. Toxicokinetic differences may account for the lack of correlations found for metal levels in hair and saliva with those in blood or urine. For those heavy metals showing higher median levels in blood with respect to hair (Cd, Mn and Pb) indicating lesser hair incorporation from blood, the lifetime working experience was inversely correlated with their hair levels. The longer the lifetime working experience in industrial environments, the higher the Mn and Ni concentration in saliva. Axillary hair and saliva may be used as additional and/or alternative samples to blood or urine for biomonitoring hair Mn, and saliva Ni in subjects with occupational exposure.

The effect of waste combustion on the occurrence of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) in breast milk in Italy

Levels of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were measured in the breast milk of mothers living in Giugliano (Campania, Italy), an area at increased risk of PCDD and PCDF exposure caused by recent and serious open-air waste-combustion accidents. Polychlorinated biphenyls (PCBs) in milk samples were also studied. Breast milk was also monitored in two cities in northern Italy, Milan and Piacenza, which were selected as controls. Other variables, such as diet and age of the mothers, were also studied. PCDD/F and PCB levels and congener profiles in breast-milk samples were similar in all these cities, though total PCDD/F and DL-PCB TEQs in samples from Giugliano were significantly lower than those in Milan and Piacenza (8.65 pg WHO-TEQ in Giugliano vs. 11.0 and 9.94 pg WHO-TEQ in Milan and Piacenza respectively). Thus no direct correlations were found between PCDD/F and PCB levels in breast milk and the suspected increased exposure through open-air waste combustion in Giugliano. Diet did not seem to affect PCDD/F and PCB levels, whereas a significant correlation was observed between the mother's age and an increased concentration of PCDDs/Fs and PCBs in milk. Comparison of these findings with those of previous surveys in Italy in 2000-2001 showed a marked reduction of PCDD/F (about 60%) and DL-PCB (about 20%) levels in breast milk occurring over the last 10 years. This might well be a result of well functioning legislation, for example European Directives on of the reduction of the emission limits of PCDDs/Fs and PCBs from waste incineration set by EU Directive 2000/76/EC implemented in 2000, or Commission Regulations such as (EC) No. 466/2001 and 1881/2006 setting maximum levels for certain contaminants in foodstuffs.

Heavy metal levels (Pb, Cd, Cr and Hg) in the adult general population near an urban solid waste incinerator

In 2005 an urban solid waste incinerator (SWI) was commissioned in Bilbao (Basque Country, Spain). Serum and urine samples were collected from 95 and 107 volunteers in 2006 and 2008 respectively, of which 62 were repeats from the same individuals. Blood lead levels (BPb) were determined, as were the concentrations of cadmium (Cd), chromium (Cr) and mercury (Hg) in urine (UCd, UCr and UHg). The town of Alonsotegi and a borough of Bilbao (Altamira, Rekalde) were considered to be close, less than 2 km from the plant, and correspond to an urban environment with high traffic density. The areas of reference were a borough of Bilbao (Santutxu-Zurbaran), 5 km from the plant, also in an urban area with high traffic density, and a small town with little industrial activity and low traffic density (Balmaseda) 20 km from the plant; neither of these is downwind from the site with respect to prevailing winds. There was a significant correlation for BPb, r=0.63 (p<0.001), between the two surveys. However, there was no linear correlation for the other three metals (UCd, UCr and UHg), between the two sampling periods (p>0.05). Multiple linear regression models did not show increases over time of the levels of BPb, UCd, UCr and UHg in the areas close to the SWI compared to those of areas located further away, after adjusting for confounding variables. These results reinforce the hypothesis that populations near modern plants for solid waste incineration do not manifest increased levels of heavy metals.

Concentrations of PCDD/Fs, PCBs and PBDEs in breast milk of women from Catalonia, Spain: a follow-up study

The concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) were determined in breast milk from women living in the vicinity of a new hazardous waste incinerator (HWI) in Catalonia, Spain. The results were compared with the levels obtained in two previous surveys carried out in 1998 (baseline study) and 2002. The current concentrations of PCDD/Fs in breast milk ranged from 45 to 143 pg/g fat (2.8 to 11.2 pg WHO-TEQ/g fat), while total PCBs ranged from 114 to 617 pg/g fat (2.8 to 17.6 pg WHO-TEQ/g fat). PBDE concentrations (sum 15 congeners) ranged from 0.57 ng/g fat to 5.9 ng/g fat, with a mean value of 2.5 ng/g fat. A general decrease of the concentrations for PCDD/Fs and both planar and total PCBs was observed. Regarding to PBDE concentrations in breast milk, similar levels between the 2002 and the present study were noted. The levels of PCDD/Fs and PCBs in milk of women living in urban areas were higher than those corresponding to the industrial zones (38% and 40%, respectively). However, the current PBDE levels were slightly lower (13%) in the urban than in the industrial zone. For PCDD/Fs and PCBs, the current decreases are in accordance with the reduction in the dietary intake of these pollutants found in recent studies carried out in the same area of study.

Urinary 1-hydroxypyrene and PAH exposure in 4-year-old Spanish children

AIMS

Exposure to polycyclic aromatic hydrocarbons (PAH), among the main compounds present in polluted urban air, is of concern for children's health. Childhood exposure to PAH was assessed by urinary monitoring of 1-hydroxypyrene (1-OHP), a pyrene metabolite, investigating its association with exposure to air pollution and other factors related to PAH in air.

METHODS

A group of 174 4-year-old children were recruited and a questionnaire on their indoor and outdoor residential environment was completed by parents. At the same time, environmental measurements of traffic-related air pollution (NO2) were carried out. A urine sample was collected from each child in order to analyze 1-OHP using HPLC with fluorescence detection, correcting for creatinine concentrations. Non-parametric tests and regression analyses were used to identify environmental factors that influence 1-OHP excretion.

RESULTS

Mean urinary 1-OHP concentration was 0.061 micromol/mol creatinine, ranging from 0.004 to 0.314 micromol/mol. Non-parametric tests and regression analysis showed positive and significant associations (P<or=0.05) between 1-OHP and predicted residential exposure to NO2 (which was based on outdoor environmental measurements and geo-statistical analysis), self-reported residential vehicle traffic, passive smoking and cooking appliance. 1-OHP levels tended to be higher among children living in urban areas (0.062 micromol/mol vs. 0.058 micromol/mol for children living in rural areas) but differences were not significant (P=0.20).

CONCLUSION

In Southern Spain, concentrations of urinary 1-OHP were in the lower range of those generally reported for children living in non-polluted areas in Western Europe and the USA. Traffic-related air pollution, passive smoking and cooking appliance influenced urinary 1-OHP level in the children, which should be prevented due to the health consequences of the inadvertent exposure to PAH during development.

Non-invasive matrices in human biomonitoring: a review

Humans and other living organisms are exposed to a variety of chemical pollutants that are released into the environment as a consequence of anthropogenic activities. Environmental pollutants are incorporated into the organism by different routes and can then be stored and distributed in different tissues, which leads to an internal concentration that can induce different alterations, adverse effects and/or diseases. Control measures should be taken to avoid these effects and human biomonitoring is a very useful tool that can contribute to this aim. Human biomonitoring uses different matrices to measure the target chemicals depending on the chemical, the amount of matrix necessary for the analysis and the detection limit (LOD) of the analytical technique. Blood is the ideal matrix for most chemicals due to its contact with the whole organism and its equilibrium with organs and tissues where chemicals are stored. However, it has an important disadvantage of being an invasive matrix. The development of new methodology and modern analytical techniques has allowed the use of other matrices that are less or non-invasive, such as saliva, urine, meconium, nails, hair, and semen or breast milk. The presence of a chemical in these matrices reflects an exposure, but correlations between levels in non-invasive matrices and blood must be established to ensure that these levels are related to the total body burden. The development of new biomarkers that are measurable in these matrices will improve non-invasive biomonitoring. This paper reviews studies that measure Cd, Pb, Hg, polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ethers (PBDEs), organochlorine pesticides and phthalates in non-invasive matrices, the most used techniques for measurements and what alternative techniques are available.

Concentrations of PCDD/PCDFs in plasma of subjects living in the vicinity of a hazardous waste incinerator: follow-up and modeling validation

In 2007, the concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDFs) were determined in plasma of non-occupationally exposed subjects living near the only hazardous waste incinerator (HWI) in Spain (Constantí, Tarragona County, Catalonia). These data were compared with the levels found in two previous surveys performed in 1998 (baseline) and 2002. The current mean PCDD/PCDF concentration in plasma was 9.36pg I-TEQg(-1) of lipid (range: 1.76-23.44pg I-TEQg(-1) of lipid). It means a significant reduction of the mean PCDD/PCDFs levels in plasma in comparison to the concentrations found in 1998 and 2002 (27.01 and 15.70pg I-TEQg(-1) of lipid, respectively). This important decrease agrees well with the notable reduction in the dietary intake of PCDD/PCDFs recently noted for the population of the same area (210.1pg I-TEQd(-1), 63.8pgWHO-TEQd(-1), and 27.8pgWHO-TEQd(-1), in 1998, 2002 and 2007, respectively). The current data were also used to predict theoretical PCDD/PCDF concentrations in plasma by executing a single-compartment empirically-based pharmacokinetic model on the basis of the daily intake of these pollutants by the local population.

Monitoring PCDD/Fs and other organic substances in workers of a hazardous waste incinerator: a case study

The aim of this study was to measure, 6 years after regular operations, the concentrations of a number of organic substances in blood and urine of 19 workers employed at a hazardous waste incinerator (HWI) in Spain, and to establish the temporal variation with respect to baseline data and previously performed surveys. This facility was the first, and so far the only HWI in that country. The levels of hexachlorobenzene (HCB), polychlorinated biphenyls (PCB 28, 52, 101, 138, 153 and 180) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were analyzed in six composite plasma samples, while concentrations of di-, tri, and pentachlorophenols, as well those of 1-hydroxypyrene were measured in the urine of these workers. The current mean PCDD/F concentration, 10.4 ng I-TEQ/kg lipid, was significantly lower than that found in the baseline survey, 26.7 ng I-TEQ/kg lipid and similar to that found in the previous (2004) study (7.7 ng I-TEQ/kg lipid). PCDD/F levels in plasma were similar or even lower than those recently reported for various non-exposed populations. For the remaining analyzed substances in plasma and urine, there was not any significant increase in comparison with the levels found in the baseline survey. On the other hand, no marked differences between the concentrations of organic substances in plasma or urine were found according to the respective workplace (plant, laboratory and administration). The results of the present survey indicate that after 6 years of regular operation, the workers at the HWI are not occupationally exposed to PCDD/Fs and other organic substances in their workplaces.

Association between tofu intake and serum polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the elderly Taiwanese

Age and gender are related to human dietary habits, which affect serum levels of dioxin-like compounds via body fat content. This study examined whether different dietary patterns and body fat content were associated with serum polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) concentrations for different age groups of Taiwanese subjects. In total, 1165 volunteers completed a semi-quantitative food-consumption frequency questionnaire for serum PCDD/Fs analysis. In the elderly (age, >45 years), a significant positive multivariate-adjusted association was identified between serum PCDD/F levels and sea fish intake. Additionally, consumption of tofu was negatively correlated with serum PCDD/F levels. This study also found a negative correlation between tofu intake and body fat content in the elderly. It seems that when elderly people ingested considerable amounts of soybean protein, such as tofu, they typically had low serum PCDD/Fs levels in relation to reduced body fat content and induction of metabolic enzymes. The relationship between tofu intake, metabolic enzymes, and serum PCDD/F accumulations warrants further investigated previously to recommend how to prevent PCDD/F accumulations via intake of soybean products.

Impact of iron and steel industry and waste incinerators on human exposure to dioxins, PCBs, and heavy metals: results of a cross-sectional study in Belgium

We evaluated the impact of two iron and steel plants and two municipal solid waste incinerators (MSWI) in Wallonia (Belgium) on the exposure of residents to dioxins, polychlorinated biphenyls (PCBs), and heavy metals. In total, 142 volunteers living around these facilities were recruited and compared with 63 referents from a rural area with no industrial source of pollution. Information about smoking habits, dietary habits, anthropometric characteristics, residential history, and health status was obtained from a self-administered questionnaire. The volunteers provided blood under fasting conditions in order to evaluate the body burden of dioxins (17 polychlorinated dibenzo-p-dioxins/dibenzofurans [PCDD/Fs] congeners) and PCBs. Samples of blood and urine were also taken for the determination of cadmium, mercury, and lead. After adjustment for covariates, concentrations of cadmium, mercury, and lead in urine or blood were not increased in subjects living in the vicinity of MSWIs or sinter plants by comparison with referents. Residents around the sinter plants and the MSWI located in the industrial area had concentrations of dioxins and PCBs in serum similar to that of referents. By contrast, subjects living in the vicinity of the MSWI in the rural area showed significantly higher serum levels of dioxins (geometric mean, 38 vs. 24 pg TEQ/g fat) and coplanar PCBs (geometric mean, 10.8 vs. 7.0 pg TEQ/g fat). Although age-adjusted dioxin levels in referents did not vary with local animal fat consumption, concentrations of dioxins in subjects living around the incinerators correlated positively with their intake of local animal fat, with almost a doubling in subjects with the highest fat intake. These results indicate that dioxins and coplanar PCBs emitted by MSWIs can indeed accumulate in the body of residents who regularly consume animal products of local origin.

Survey of urinary nickel in residents of areas with a high density of electroplating factories

The soil metal contamination arising from the discharge of the high density of electroplating factories in the geographic center of Taiwan has prompted concern about human exposure to harmful metals. This study aimed to determine the levels of nickel (Ni) in urine of residents living in the high vs. low factory-density areas, and to examine how these levels relate to gender and age. A total of 660 subjects, resident in the area for the last five years, were sampled according to the stratified random sampling approach, at ages 35-44, 45-54, and 55-64years for both genders. Metals in urine samples were analyzed by inductively coupled plasma mass spectrometry (ICPMS). The geometric mean (95% confidence interval (CI)) of urinary Ni was 6.30 (5.99-6.62)mug/l. The 0.95 parametric reference interval (90% CI) of urinary Ni was estimated to be 1.74 (1.62-1.88) to 22.73 (21.14-24.44)mug/l. Subjects in the areas with a high density of electroplating factories had significantly higher urinary Ni levels than those in the low-density areas, but both types of areas had obviously higher urinary Ni levels when compared to the non-occupationally exposed population from western countries. The health significance of elevated urinary Ni and its causative factors remain to be determined.

Exposure assessment of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in temporary municipal-waste-incinerator maintenance workers before and after annual maintenance

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) have been found in ambient air around municipal waste incinerators (MWIs), and elevated serum levels in incinerator workers have also been observed in some studies. However, few studies have focused on temporary employees who work intermittently through the annual maintenance and clean-up around different incinerators. The present study aimed to assess the change in serum PCDD/F levels of temporary employees between the beginning of periodic incinerator maintenance and one month the work was completed. Thirty-five volunteer workers, most of them transient and temporary maintenance staff, were recruited from a contractor that provided annual maintenance for four incinerators in this study. Information about each participant was obtained by questionnaire at the beginning of annual maintenance. The questionnaire asked for work history, health status, and diet information. As measured by the PCDD/F levels in blood, a significant increase was observed in workers after a month of maintenance work. The increase was greater in workers who had never done this type of maintenance than in those with previous experience, especially for 2,3,4,6,7,8-HxCDF levels. The data also showed that the laborers and employers need to pay more attention to occupational health issues even for short-term incinerator maintenance workers.

Persistent organochlorine pollutants in children working at a waste-disposal site and in young females with high fish consumption in Managua, Nicaragua

The aim of this study was to assess persistent organochlorine pollutant (POP) levels in serum collected from children (11-15 years old) working and sometimes also living at the municipal waste-disposal site in Managua, located at the shore of Lake Managua, and in nonworking children living both nearby and also far away from the waste-disposal site. The influence of fish consumption was further evaluated by assessing POPs levels in serum from young women (15-24 years old) with markedly different patterns of fish consumption from Lake Managua. 2,2-bis(4-chlorophenyl)-1,1,1-trichloro-ethane (4,4'-DDT) and 2,2-bis(4-chlorophenyl)-1,1-dichloro-ethene (4,4'-DDE), gamma-hexachlorocyclohexane (gamma-HCH), polychlorinated biphenyls, pentachlorophenol, and polychlorobiphenylols were quantified in all samples. In general, the levels observed were higher than those reported in children from developed countries, such as Germany and United States. Toxaphene, aldrin, dieldrin, and beta-HCH could not be identified in any sample. The children working at the waste-disposal site had higher levels of POPs compared with the nonworking reference groups. In children not working, there were also gradients for several POPs, according to vicinity to the waste-disposal site. Moreover, in children, as well as in young women, there were gradients according to fish consumption. The most abundant component was 4,4'-DDE, but at levels still lower than those reported in children from malarious areas with a history of recent or current application of 4,4'-DDT for vector control.

Fatty liver and hepatic function for residents with markedly high serum PCDD/Fs levels in Taiwan

This study was designed to examine the associations between serum polychtorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) levels and adverse hepatic-related health outcomes. Residents living in the vicinity of a closed pentachlorophenol (PCP) manufacturing factory (exposure area) and other areas nearby (control area) were identified from prior investigation of serum PCDD/Fs measurements. A total of 85 subjects were recruited for the study, 52 from exposure area and 33 from control, respectively. Average level of serum PCDD/Fs was 80.1 6 50.9 pg WHO-TEQ/g lipid for those residing in exposure area, and 25.5 6 18.2 in control area. Statistically higher odds ratio (ORs) for fatty liver and gamma-glutamyltransferase (GGT) activity was found in subjects with higher serum PCDD/Fs levels and high body mass index (BMI) as compared to those with lower PCDD/Fs levels and less BMI. Data suggest that dioxin exposure and high lipid content affect the prevalence of fatty liver in exposed subjects. Future study should be directed to prevent continuous exposure to environmental PCDD/Fs from the defunct PCP factory, and to characterize prospectively, with a larger study sample size, the potential long-term consequences on hepatic function associated with contaminant exposure.

Urinary metal and polycyclic aromatic hydrocarbon biomarkers in boilermakers exposed to metal fume and residual oil fly ash

BACKGROUND

Boilermakers are occupationally exposed to known carcinogens.

METHODS

The association of urinary 1-hydroxy-pyrene (1-OHP), a biomarker of polycyclic aromatic hydrocarbon (PAH) exposure, with biomarkers of metal exposure (vanadium, chromium, manganese, nickel, copper, and lead) in boilermakers exposed to metal fume from welding and dust particulates from residual oil fly ash (ROFA) was examined. A repeated measures cohort study was conducted during the overhaul of an oil-fired boiler. Twice-daily urine samples were obtained for 5 days and analyzed for cotinine, 1-OHP, and metals. Generalized estimating equations (GEE) were used to model the multivariate relationship of 1-OHP to the explanatory variables.

RESULTS

Metal and 1-OHP levels were determined for 165 urine samples from 20 boilermakers and these levels increased during the workweek. However, the 1-OHP level was not significantly associated with any individual metal level at any time point.

CONCLUSION

This suggests that boilermakers were occupationally exposed to PAH and metals, but 1-OHP as a PAH biomarker was unable to serve as a surrogate marker of metal exposure for the metals measured in this study.

Evaluation of serum dioxin congeners among residents near continuously burning municipal solid waste incinerators in Korea

The objective of this study was to evaluate the congeners of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in Korean serum samples as biological markers. Serum samples from 103 participants were analyzed. Participants consisted of 28 workers in municipal solid waste incinerators (MSWIs), and 21 men and 54 women who had lived for at least 3 years prior to 2002 in areas within 300 m of incinerators in large Korean cities. Serum samples were analyzed for 17 PCDD/PCDFs congeners by high resolution gas chromatography-high resolution mass spectrometry. Geometric mean (GM) PCDD/PCDF levels in the serum samples were 3.14, 8.04, 6.12 and 6.60 pg TEQ/g lipid for workers, male residents, female residents and the sum of male and female residents, respectively. The GM PCDD/PCDF level in the serum of workers was not significantly different from the values for residents near MSWIs. In the 75 participants who resided near MSWIs, the congeners that most contributed to the total TEQ were 1,2,3,6,7,8-hexachlorodibenzofuran (1,6-HxCDF), 2,3,4,7,8-pentachlorodibenzofuran (4-PeCDF), 1,2,3,4,6,7,8-heptachlorodibenzofuran (1,4,6-HpCDF), 1,2,3,7,8,9-hexachlorodibenzofuran (1,9-HxCDF), 1,2,3,4,7,8-hexachlorodibenzo-p-dioxin (1,4-HxCDD), 1,2,3,6,7,8-hexachlorodibenzo-p-dioxin (1,6-HxCDD). In the workers, the congeners that made the greatest contribution were 1,6-HxCDD, 4-PeCDF, 1,2,3,4,6,7,8-heptachlorodibenzop-dioxin (HpCDD), and 1,6-HxCDF. In conclusion, the serum TEQ levels for PCDD/PCDFs in the incinerator workers and residents near the MSWIs in Korea were lower than those reported for other countries. Comparison of the PCDD/PCDF levels of workers at MSWIs and nearby residents revealed no significant enhancement of PCDD/PCDF exposure in workers. PCDD/PCDF intake from animal origin was assumed to be lower than that of Europeans. Further studies of Korean foods are needed to clarify the exposure route for PCDD/PCDFs in the Korean population.

Levels of dioxins and furans in plasma of nonoccupationally exposed subjects living near a hazardous waste incinerator

The potential adverse effects of hazardous waste incinerators (HWI) continue to be a subject of worry. The construction of the first and till now only HWI in Spain finished in 1999. To assess the potential impact of the plant on public health, a preoperational monitoring program was established during the period of construction. The main goal of the present study was to determine, after approximately 3 years of regular operations in the facility, the concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in plasma of nonoccupationally exposed subjects living near the HWI. Blood samples were obtained from 20 volunteers aged 19-62 years. The mean PCDD/F concentration in plasma was 15.70 pg I-TEQ/g lipid (range 4.66-29.25 pg I-TEQ/g lipid), which is significantly lower than the mean level found in the baseline survey, 27.01 pg I-TEQ/g lipid (range 14.79-48.95 pg I-TEQ/g lipid). Reductions were noted for both sexes and for all age groups. The comparison with PCDD/F levels from a number of different countries shows that, in general terms, the current PCDD/F concentrations are lower than most results recently reported. It is concluded that emissions from the stack of the HWI assessed here should not mean any additional significant exposure to PCDD/Fs for the population living near the facility.

PCDD/Fs levels in indoor environments and blood of workers of three municipal waste incinerators in Taiwan

This study monitored ambient air concentrations of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) in three municipal waste incineration plants. Blood PCDD/Fs levels of 133 workers randomly selected from these plants were also measured. The associations between workers' blood PCDD/Fs concentrations and occupational exposures to PCDD/Fs were assessed. Means of air PCDD/Fs levels ranged from 0.08 to 3.01 pg/m3 in international toxic equivalents (I-TEQ). The geometric means of blood PCDD/Fs concentrations were 14.6, 15.8, 19.1 pg/g lipid in World Health Organization (WHO) TEQ, respectively, for workers from three plants. Air levels of total I-TEQ and all congeners, except 2,3,7,8-tetrachlorinated dibenzo-p-dioxin (TeCDD) and 1,2,3,4,7,8,9-heptachlorinated dibenzofuran (HpCDF), were significantly higher in plant B. However, blood concentrations of 2,3,7,8-TeCDD, 1,2,3,7,8-PeCDD, 2,3,7,8-TeCDF, 1,2,3,7,8-PeCDF and 1,2,3,4,7,8,9-HpCDF were significantly elevated in plant C workers. Although job contents, duration of employment and time spent in certain location were significantly different among incineration plants, they were not significantly associated with blood concentrations of any congener. Furthermore, results of the multiple regression analysis that assessed important occupational factors simultaneously and adjusted for potential confounders, showed significant associations between four congeners and incineration plant or job contents. However, the results were limited by small R-squares of the regression models. In conclusion, blood concentrations of several PCDD/Fs congeners were significantly different among three incineration plants. The differences were not explained by the discrepancy in job contents, duration of employment, and time activity in these plants.