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

Time trends of PCDDs, PCDFs, DL-PCBs, and NDL-PCBs in Italian women from biomonitoring studies

A number of biomonitoring investigations were carried out in Italy between 2000 and 2018 by the Unit of Human Exposure to Environmental Chemicals of the Italian National Institute of Health (Rome). The investigations were characterized by different features (case-control or cross-sectional studies, participants from impacted or no impacted areas, etc), but despite the differences, it was possible to study the time trends of Σ₇(PCDDs), Σ₁₀(PCDFs), Σ₁₂(DL-PCBs), and Σ₆(NDL-PCBs) (analytical and TEQ cumulative concentrations, as appropriate). All the chemicals considered showed clear rates of a time-dependent concentration decrease, data having previously been adjusted for the sampled Region and subject age. Σ₇(PCDDs) exhibited the fastest decrease with an average rate of -4.44 pg/g-fat year^-1 (2009-2018), whereas Σ₆(NDL-PCBs) was characterized by the slowest decrease with a rate of -0.771 ng/g-fat year^-1 (2000-2018). A clear distinction between the decreasing rates of Σ₇(PCDDs) and Σ₁₀(PCDFs) was observed, as the latter decreased at half the rate of the Σ7(PCDDs). The slower rate of the Σ₁₀(PCDFs) decline may be due to an ongoing source of PCDFs in the environment beyond those traditionally considered for this group of contaminants such as the production of PCDFs due to PCBs thermal conversion from matrices contaminated with PCBs. Production of PCDFs due to thermal conversion of matrices contaminated with PCBs could be an ongoing source which may be of concern because recent data have highlighted the diffusion of PCBs in the European environment. The decreasing rates of PCDDs + PCDFs, DL-PCBs, and PCDDs + PCDFs + DL-PCBs - original analytical data converted to "dioxin equivalents" - were respectively estimated as (pgTEQ/g-fat year^-1) -2.08, -2.06, and -2.10, values exhibiting good compatibility between one another.

Monitoring temporal trends of dioxins, organochlorine pesticides and chlorinated paraffins in pooled serum samples collected from Northern Norwegian women: The MISA cohort study

The ubiquitous presence of legacy and emerging persistent organic pollutants (POPs) in the environmental matrices poses a potential hazard to the humans and creating public health concerns. The present study aimed to evaluate dioxins, dioxin-like polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and chlorinated paraffins (CPs) concentrations in serum of women (postpartum, pregnant and non-pregnant) from Northern Norway to better understand their exposure and contamination status as well as temporal trends across 2007-2009 (MISA 1) to 2019 (MISA 2). Sixty-two blood samples from the MISA 1 cohort and 38 samples from MISA 2 were randomly selected in this study (n = 100). Ninety samples from postpartum (MISA 1) and pregnant women (MISA 2) were randomly combined into 9 pools, with 9-11 individual samples contributing to each pool keeping the groups of pregnant and postpartum women. Remaining 10 samples from non-pregnant women (MISA 2) were allocated into separate group. Geometric mean, minimum and maximum were used to describe the serum concentrations of pooled POPs in MISA cohort. Mann-Whitney U test and independent sample t-test were applied for trend analysis of blood levels of POPs between MISA 1 and MISA 2. We found the serum concentrations of selected POPs in this study to be at lower range. Serum concentrations of dibenzo-p-dioxins (PCDDs) (p = 0.010), polychlorinated dibenzofurans (PCDFs) (p = 0.002), dioxins-like PCBs (p = 0.001), hexachlorobenzene (HCB) (p < 0.001) and p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) (p = 0.002) were decreased between the studied time. In contrast, the serum concentrations of medium chain chlorinated paraffins showed an increasing trend between 2007 and 2009 and 2019 (p = 0.019). Our findings report a particular concern of emerging contaminant medium chain chlorinated paraffin exposure to humans. Future observational studies with repeated measurements of chlorinated paraffins in general populations worldwide and large sample size are warranted.

Decreasing temporal trends of polychlorinated dibenzo-p-dioxins and dibenzofurans in adipose tissue from residents near a hazardous waste incinerator

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) are very toxic chemicals which are emitted in waste incineration and whose exposure has important adverse effects for the human health. In 2019, adipose tissue samples were collected from 15 individuals with a median age of 61 years, who had been living near a hazardous waste incinerator in Constantí (Spain). The content of PCDD/Fs in each sample was analyzed. The results were compared with data from previous studies, conducted before (1998) and after (2002, 2007 and 2013) the facility started to operate, and based on populations of similar age. In 2019, the mean concentration of PCDD/Fs in adipose tissue was 6.63 pg WHO-TEQ/g fat, ranging from 0.95 to 12.95 pg WHO-TEQ/g fat. A significant reduction was observed with respect to the baseline study (1998), when a mean PCDD/Fs concentration of 40.1 pg WHO-TEQ/g fat was found. Moreover, the current level was much lower than those observed in the 3 previous studies (9.89, 14.6 and 11.5 pg WHO-TEQ/g fat in 2002, 2007 and 2013, respectively). The body burdens of PCDD/Fs were strongly correlated with age. The significant reduction of PCDD/Fs levels in adipose tissue fully agreed with the decreasing trend of the dietary intake of PCDD/Fs by the population of the zone (from 210.1 pg I-TEQ/day in 2018 to 8.54 pg WHO-TEQ/day in 2018). Furthermore, a similar decrease has been also observed in other biological, such as breast milk and plasma. The current data in adipose tissue, as well as those in other biological monitors, indicate that the population living near the HWI is not particularly exposed to high levels of PCDD/Fs. However, biomonitoring studies cannot differentiate the impact of the HWI emissions from food consumption patterns. This question can be only solved by conducting complementary investigations and contrasting the results of monitoring and epidemiological studies.

Concentrations of persistent organic pollutants in blood of the Spanish population: Temporal trend

The present article reviews the human biomonitoring studies conducted in Spain to assess exposure to persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), polybrominated diphenyl ethers (PBDEs), and per- and poly-fluoroalkyl substances (PFAS). In general terms, important variations in POPs concentrations between Spanish regions and specific populations were observed, while no associations between exposure to POPs and adverse health outcomes were found. Moreover, occupational exposure seems not to be a risk factor with regards to POPs exposure in the Spanish population. The present review highlights the importance of conducting human biomonitoring studies to find possible associations between POPs and adverse health effects.

PCDD/Fs in paired hair and serum of workers from a municipal solid waste incinerator plant in South China: Concentrations, correlations, and source identification

Human hair has been widely used to evaluate the exposure to drugs and organic pollutants. However, reports on the relationship between polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzo-p-furans (PCDFs) in hair and the body burden of PCDD/Fs are limited. In this study, the association between PCDD/Fs in paired hair and serum samples from workers was examined in a municipal solid waste incinerator (MSWI) plant in South China. Fly ash and flue gas from the MSWI plant were also analyzed to determine the source apportionment of PCDD/Fs in the hair. The median international toxic equivalents (I-TEQs) of ΣPCDD/F in serum and hair were 28.0 pg TEQ/g (lipid weight) and 0.30 pg TEQ/g (dry weight), respectively. The indicator congener of PCDD/Fs for the TEQ levels was 2,3,4,7,8-pentachlorodibenzofuran (PeCDF) in both hair and serum, the concentrations of which both exhibited significant and strong linear dependence on the total TEQ levels (p < 0.01, R² = 0.966 and R² = 0.670, respectively). Significant positive correlations were found in the 1,2,3,6,7,8-hexachlorodibenzo-p-dioxin (HxCDD) and octachlorodibenzo-p-dioxin (OCDD) levels between the hair and serum samples (p < 0.05). Flue gas (which is an external source) was identified as the primary source of PCDD/Fs in human hair. Blood and flue gas were accountable for, on average, 37% and 61% of the PCDD/Fs in hair, respectively.

Health risk of childhood exposure to PCDD/Fs emitted from a municipal waste incinerator in Zhejiang, China

This study aimed to evaluate the body burdens of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and their associated health impacts toward school-age children living near a municipal waste incinerator (MWI). A total of 82 children from the exposure area and 49 from the control area were recruited. We measured blood PCDD/F levels, conducted comet assays, calculated the percentage of 5-methylcytosine (%5-mC) and 5-hydroxymethylcytosine (%5-hmC), performed flow cytometry, measured hormonal levels, and analyzed hematological parameters. We also examined 17 congeners of PCDD/Fs in environmental samples, namely, eggs, rice, water, soil, and PM_2.5. The mean blood levels of ΣPCDD/Fs and TEQ-ΣPCDD/Fs were statistically higher in the exposure group than in the control group (3.40 vs. 2.77 pg/g wet weight and 0.40 vs. 0.28 pg WHO-TEQ/g wet weight, respectively; p < 0.05). By contrast, the %5-mC and %5-hmC levels were statistically lower in the exposure group than in the control group (1.15% vs. 4.66% and 0.22% vs. 0.30%, respectively; p < 0.01), whereas the mean % tail DNA was statistically higher in the exposure group than in the control group (10.10% vs. 8.28%, p < 0.01). The mean blood levels of ΣPCDD/Fs and TEQ-ΣPCDD/Fs were both negatively correlated with %5-mC (r = -0.245 and r = -0.217, respectively; p < 0.01) but not with %5-hmC and % tail DNA (p > 0.05). Furthermore, the mean ΣPCDD/F levels in eggs and soil obtained from the exposure area were statistically higher than those of the samples obtained from the control area (31.08 vs. 4.32 pg/g dry weight and 1026.04 vs. 674.97 pg/g dry weight, respectively). In conclusion, children living near the MWI may suffer genetic and epigenetic modifications, such as DNA damage or global DNA hypomethylation due to the MWI-emitted PCDD/Fs and other contaminants.

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.

Body burdens of heavy metals associated with epigenetic damage in children living in the vicinity of a municipal waste incinerator

To evaluate the body burdens of heavy metals correlated with health impact on school-age children living around a waste incinerator. A total of 81 children from the exposure area and 95 from the control area were recruited in our study. We measured the blood levels of chromium (Cr), cadmium (Cd) and lead (Pb) by an inductively coupled plasma mass spectrometer (ICP-MS), conducted comet assays, calculated the percentage of 5-methylcytosine (5 mC) and 5-hydroxymethylcytosine (5hmC) by MethylFlash methylated and a hydroxymethylated DNA quantification kit, and performed the flow cytometry to detect the expressions of surface antigens (including CD3⁺, CD19⁺, CD3⁺CD4⁺, CD3⁺CD8⁺, and CD3^-CD16⁺ and/or CD56⁺) in peripheral lymphocytes. Besides, we measured hormonal levels, including triiodothyronine (T3), thyroxine (T4), free triiodothyronine (FT3), free thyroxine (FT4), and thyroid-stimulating hormone (TSH), and analyzed several regular hematological parameters. In addition, concentrations of heavy metals in environmental samples including rice, soils, vegetables, and drinking water were detected by ICP-MS. The mean blood levels of Cr, Cd, and Pb in the exposure group were all statistically higher than in the control group (2.57 vs. 0.79 μg/L; 1.83 vs. 1.81 μg/L; 44.00 vs. 32.31 μg/L, p < 0.01). The 5 mC and 5hmC levels in the exposure group were statistically lower (1.15% vs. 4.14%; 0.22% vs. 0.30%, p < 0.01), whereas the mean level of % tail DNA was statistically higher (10.10% vs. 8.62%, p < 0.01). Furthermore, the mean blood level of Cr and Pb was negatively correlated with the level of 5 mC (r = -0.279, r = -0.190, P < 0.05) in total population. In conclusion, children living in the vicinity of the municipal waste incinerator suffered increased body burdens of heavy metals (Cr, Cd, and Pb) associated with genotoxicity and epigenetic modifications.

High intake of persistent organic pollutants generated by a municipal waste incinerator by breastfed infants

To monitor the body burden of persistent organic pollutants in mothers and infants living in proximity to a 10-year-old municipal waste incinerator (MWI), levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) in the breast milk of mothers were evaluated, and the estimated daily intake (EDI) level of these pollutants in infants was assessed. In total, 14 mothers from the exposure area and 18 mothers from a control area were recruited for this study. In addition, the levels of 17 PCDD/F congeners and 18 PCB congeners in the breast milk of the mothers were estimated, and risk assessment for their infants by calculating their EDI levels was performed. The mean levels of ΣPCDD/Fs and TEQ-ΣPCDD/Fs in the breast milk of the exposure group were significantly greater than those of the control group (3.36 vs. 1.47 pg/g wet weight; and 0.24 vs. 0.12 pg TEQ/g wet weight, respectively; p < 0.05). With respect to PCBs, the mean levels of the total PCBs (ΣPCBs) and non-dioxin like-PCBs (ΣNDL-PCBs) in the exposure group were significantly greater than those in the control group (269 vs. 141 pg/g wet weight; 230 vs. 115 pg/g wet weight, respectively; p < 0.05). The mean levels of ΣPCDD/Fs and TEQ-ΣPCDD/Fs were positively correlated with the inhabit time of the exposure group (r = 0.636, r = 0.629, p < 0.05, respectively). The mean EDI level of the exposure group in infants was significantly greater than that of the control group (22.0 vs. 13.0 pg TEQ/kg bw day; p < 0.05). In conclusion, mothers and their breast-fed infants living in proximity to the 10-year-old MWI located in the Zhejiang Province of China exhibited a significantly higher body burden of PCDD/Fs and PCBs compared to those living in the control area.

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.

Concentrations of PCDD/Fs in the neighborhood of a hazardous waste incinerator: human health risks

In 1996-1998, a wide surveillance program was initiated in the vicinity of a new hazardous waste incinerator (HWI) placed in Constantí (Catalonia, Spain), which started its regular operations in 1999. The program was aimed at assessing the environmental impact of the facility on the surrounding environment, as well as to evaluate the potential risks for the population living in the neighborhood. Since then, among other measurements, the concentrations of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) have been periodically determined in soil and herbage samples. This study shows the results, corresponding to the period 2013-2016. Data were compared with those obtained in the baseline survey (1996-1998), as well as with those of the previous survey (2011-2012). The median PCDD/F concentrations in soils were 0.44 and 0.33 ng toxic equivalent (I-TEQ)/kg in 2015 and 2016, respectively, with a significant decrease in relation to the baseline survey, and a non-significant decrease between 2015 and 2016. In turn, PCDD/F levels in vegetation showed some fluctuations over time, being the concentrations of PCDD/Fs in 2013 very similar to those found in 2012 (1.11 and 1.23 ng I-TEQ/kg, respectively). These concentrations notably decreased along the three last campaigns (0.16, 0.23, and 0.17 ng I-TEQ/kg in 2014, 2015, and 2016, respectively). These changes would be more related to a number of environmental factors rather than to a variation of PCDD/F emissions by the HWI. With respect to human health risks, exposure to PCDD/Fs in the area under potential influence of the HWI is not of concern, as the current environmental concentrations of PCDD/Fs do not mean additional carcinogenic or non-carcinogenic risks for the local population.

Autopsy tissues as biological monitors of human exposure to environmental pollutants. A case study: Concentrations of metals and PCDD/Fs in subjects living near a hazardous waste incinerator

Human biomonitoring is of tremendous importance to prevent potential adverse effects derived from human exposure to chemicals. Blood and urine are among the biological monitors more frequently used. However, biological matrices such as breast milk, hair, nails, saliva, feces, teeth, and expired air are also often used. In addition, and focused mainly on long-term exposure, adipose tissue and other human tissues like bone, liver, brain or kidney, are also used as biological monitors of certain substances, especially for long-term biomonitoring. However, for this kind of tissues sampling is always a limiting factor. In this paper, we have examined the role of autopsy tissues as biological monitors of human exposure to environmental pollutants. For it, we have used a case study conducted near a hazardous waste incinerator (HWI) in Catalonia (Spain), in which the concentrations of metals and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), have been periodically determined in autopsy tissues of subjects living in the area under potential influence of the facility. This case study does not show advantages -in comparison to other appropriate biomonitors such as blood- in using autopsy tissues in the monitoring of long-term exposure to metals and PCDD/Fs.

Levels of PCDDs, PCDFs and dl-PCBs in the blood of childbearing-aged women living in the vicinity of a chemical plant in Tianjin: a primary study

Several studies have suggested that maternal exposure to Polychlorinated dibenzo-p-dioxins (PCDDs), poly-chlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (PCBs) may affect foetal growth and infant development. The aim of our study was to determine whether the childbearing-aged residents living near a chemical plant have a greater exposure risk. Concentrations of 17 PCDD/Fs congeners and 12 non-ortho and mono-ortho dioxin-like PCBs were measured using HRGC-HRMS in the blood of 30 non-occupational childbearing-aged women living near a chemical plant (Dagu) that had been producing chlorinated pesticides from 1958 to 2004. The factors that influenced the body burden were investigated based on responses to a questionnaire. Levels of PCDD/Fs+PCBs were in the range of 16.43-155.29pg WHO 2005-TEQg(-1) lipid. PCDDs and PCDFs contributed 56.72% and 34.44%, respectively, to the total TEQ value. Total WHO-TEQ was approximately tenfold higher in the participants living in the vicinity of the plant (distance: 1.52±0.148km) than in the groups living farther away (distance: 4.93±1.124km). A negative correlation between total WHO-TEQ and distance to Dagu was observed by multiple linear regression models. The data provide basic information for monitoring dioxin-like chemicals in the district and for the future study of the relationship between POPs and pregnancy outcomes.

A PBPK model to estimate PCDD/F levels in adipose tissue: comparison with experimental values of residents near a hazardous waste incinerator

This study was aimed at determining the concentrations of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) in 15 samples of adipose tissue from subjects who had been living in the vicinity of a hazardous waste incinerator (HWI). The results were compared with levels obtained in previous surveys carried out in 1998 (baseline study), 2002 and 2007. The current (2013) concentrations of PCDD/Fs in adipose tissue ranged from 2.8 to 46.3 pg WHO-TEQ/g fat (mean and median concentrations: 11.5 and 7.4 pg WHO-TEQ/g fat, respectively), being significantly lower (64%) than those observed in 1998. In contrast, no significant differences in the mean PCDD/F concentrations were noted in the period 2002-2013. The significant decrease of the PCDD/F content in fat, also noted in other biological monitors such as plasma and breast milk, is in agreement with the reduction in the dietary intake of PCDD/Fs found in the same area of study. Similarly to other investigations across Europe, an increase of PCDD/F levels in adipose tissue in relation to age was observed, while no significant differences were noted according to gender. A multicompartmental physiologically-based pharmacokinetic (PBPK) model was also applied to estimate the levels of PCDD/Fs in adipose tissue. When comparing the modeled and experimental concentrations of PCDD/Fs in that tissue, very similar values were obtained for the four surveys, which indicates this can be a reliable tool to predict the internal dose of PCDD/Fs.

Human exposure to metals: levels in autopsy tissues of individuals living near a hazardous waste incinerator

The concentrations of a number of metals were determined in the brain, bone, kidney, liver, and lung of 20 autopsied subjects who had lived, at least 10 years, in the neighborhood of a hazardous waste incinerator (HWI) in Tarragona (Catalonia, Spain). Results were compared with those obtained in 1998 (baseline survey) and previous surveys (2003 and 2007). Arsenic, Be, Ni, Tl, and V showed concentrations below the corresponding detection limits in all tissues. Cadmium showed the highest levels in the kidney, with a mean value of 21.15 μg/g. However, Cd was found below the detection limit in the brain and bone. Chromium showed similar concentrations in the kidney, brain, and lung (range of mean values, 0.57-0.66 μg/g) and higher in the bone (1.38 μg/g). In turn, Hg was below the detection limit in all tissues with the exception of the kidney, where the mean concentration was 0.15 μg/g (range, <0.05-0.58 μg/g). On the other hand, Mn could be detected in all tissues showing the highest levels in the liver and kidney (1.45 and 1.09 μg/g, respectively). Moreover, Pb showed the highest concentrations in bone (mean, 1.39 μg/g; range, <0.025-4.88 μg/g). Finally, Sn could be detected only in some tissue samples, reaching the highest values in the bone (0.17 μg/g). The current metal levels in human tissues from individuals living near the HWI of Tarragona are comparable and of a similar magnitude to previously reported results corresponding to general populations, as well as those of our previous surveys.

Ten-year time trend of dioxins in human serum obtained from metropolitan populations in Seoul, Korea

Polychlorinated dibenzo-p-dioxin/furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) were measured in 954 and 539 human serum samples obtained, respectively, from incinerator workers and residents living near and far from municipal solid waste incinerators (MSWIs) during a 10-year period from 2001 to 2011 in Seoul, Korea. The mean toxic equivalent (TEQ) concentrations of PCDD/Fs and DL-PCBs were 9.29 and 5.39 pg TEQ/g lipid, respectively. All populations exhibited similar concentrations and profiles, and 2,3,4,7,8-PeCDF, 1,2,3,7,8-PeCDD, and PCB126 were identified as major contributors to TEQs. However, the levels of PCDD/Fs and DL-PCBs were found to have positive associations with age when considering stratified age groups and showed a slight trend toward reduction. Differences in concentrations of these compounds among age groups slightly but continuously decreased from 2001 to 2011. The measured PCDD/F levels were compared to the predicted concentrations by using a single-compartment pharmacokinetic model on the basis of the daily intake of PCDD/Fs. The predicted concentration was 5.24 pg TEQ/g lipid, which was approximately half of the measured concentration, reflecting the present exposures. These results suggest that current data on the levels of PCDD/Fs in foodstuffs might be useful to predict the future levels of dioxins in humans, which are expected to decline with time.

PCDD/Fs in plasma of individuals living near a hazardous waste incinerator. A comparison of measured levels and estimated concentrations by PBPK modeling

The construction of the first and, until now, only hazardous waste incinerator (HWI) in Spain finished in 1998. To assess its potential impact on the population living in the vicinity, a surveillance program was established. It includes the periodical biomonitoring of PCDD/Fs body burden. On the basis of this program, in 2012 we determined the levels of PCDD/Fs in plasma of nonoccupationally exposed individuals living near the HWI. The results were compared with those of the baseline study, and with those of two previous surveys (2002 and 2007). A multicompartment, physiologically based pharmacokinetic (PBPK) model was also applied to estimate the levels of PCDD/Fs in plasma. The model was validated by comparing the results with our experimental data (baseline, 2002, 2007, and 2012). The current mean concentration was 6.18 pg I-TEQ/g lipid, with a range between 2.03 and 18.8 pg I-TEQ/g lipid. In 1998 (baseline), the mean concentration of PCDD/Fs in plasma was 27.0 pg I-TEQ/g lipid (reduction of 77%, p < 0.001). Significant reductions were also noted in our previous 2002 and 2007 surveys, with mean concentrations of 15.7 and 9.36 pg I-TEQ/g lipid, respectively. However, the comparison between simulated (using the PBPK model) and experimental results was very successful, as PCDD/F values in plasma were very similar (7.95 vs 6.18 pg I-TEQ/g lipid). The levels of PCDD/Fs in plasma of nonoccupationally exposed individuals living near the HWI here assessed are comparatively lower than most recently reported values.

Residential proximity to industrial combustion facilities and risk of non-Hodgkin lymphoma: a case-control study

BACKGROUND

Residence near municipal solid waste incinerators, a major historical source of dioxin emissions, has been associated with increased risk of non-Hodgkin lymphoma (NHL) in European studies. The aim of our study was to evaluate residence near industrial combustion facilities and estimates of dioxin emissions in relation to NHL risk in the United States.

METHODS

We conducted a population-based case-control study of NHL (1998-2000) in four National Cancer Institute-Surveillance Epidemiology and End Results centers (Detroit, Iowa, Los Angeles, Seattle). Residential histories 15 years before diagnosis (similar date for controls) were linked to an Environmental Protection Agency database of dioxin-emitting facilities for 969 cases and 749 controls. We evaluated proximity (3 and 5 km) to 10 facility types that accounted for >85% of U.S. emissions and a distance-weighted average emission index (AEI [ng toxic equivalency quotient (TEQ)/year]).

RESULTS

Proximity to any dioxin-emitting facility was not associated with NHL risk (3 km OR = 1.0, 95% CI 0.8-1.3). Risk was elevated for residence near cement kilns (5 km OR = 1.7, 95% CI 0.8-3.3; 3 km OR = 3.8, 95% CI 1.1-14.0) and reduced for residence near municipal solid waste incinerators (5 km OR = 0.5, 95% CI 0.3-0.9; 3 km OR = 0.3, 95% CI 0.1-1.4). The AEI was not associated with risk of NHL overall. Risk for marginal zone lymphoma was increased for the highest versus lowest quartile (5 km OR = 2.6, 95% CI 1.0-6.8; 3 km OR = 3.0, 95% CI 1.1-8.3).

CONCLUSIONS

Overall, we found no association with residential exposure to dioxins and NHL risk. However, findings for high emissions and marginal zone lymphoma and for specific facility types and all NHL provide some evidence of an association and deserve future study.

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.

Concentrations of metals in soils in the neighborhood of a hazardous waste incinerator: assessment of the temporal trends

The concentrations of arsenic (As), beryllium (Be), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), mercury (Hg), manganese (Mn), nickel (Ni), lead (Pb), antimony (Sb), tin (Sn), thallium (Tl), and vanadium (V) were determined in 30 soil samples collected in April 2011 near a hazardous waste incinerator (HWI; Constantí, Catalonia, Spain), which is under regular operations since 1999. The results were compared with those of recent surveys performed in the same zone, as well as with data from a background study (1996-1998). We also assessed the human health risks derived from metal exposure in the area under potential influence of the emissions of the HWI. Manganese was the most abundant element in soils, with a mean value of 316.4 μg/g, followed by Pb and Cu (mean values, 42.5 and 38.2 μg/g, respectively). In contrast, Sb, Cd, and Tl presented the lowest values (0.12, 0.27, and 0.29 μg/g, respectively), while Hg was below its limit of detection. In the period 1998-2011, only As, Cr, Sn, Tl, and V levels presented significant increases in soils. The estimated carcinogenic and noncarcinogenic risks derived from exposure to these metals from soils should not mean any special concern for the population living in the surroundings of the HWI.

Evolution of PCDD/Fs and dioxin-like PCBs in the general adult population living close to a MSW incinerator

It is well known that municipal solid waste incinerators (MSWI) produce dioxins and furans. The aim of this study was to assess the serum levels of compounds with dioxin-like activity such as polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like PCBs after the commissioning of a MSWI plant. In 2006 and 2008 serum samples were obtained from 322 and 326 volunteers, respectively, from the general population, some living in the vicinity of the plant and others, as a control group, living further away from the MSWI plant and out of the path of prevailing winds. Samples for sets of 20 individuals, grouped by age and sex, were pooled, obtaining 16 pooled samples per year. No significant differences were observed in PCDD/Fs as a function of area of residence or proximity to the plant over the time of the study, with levels of WHO-TEQ/g lipid nearby and far from the MSWI being 26.9 and 20.0pg, respectively, in 2006 and 20.8 and 26.4pg, respectively, in 2008. There was a significant decrease in the concentration of non-ortho PCBs in the nearby areas, whilst there was a significant increase in the concentration of mono-ortho PCBs, both in the nearby areas and in those further away from the MSWI. Age was significantly associated with PCDD/Fs and dioxin-like PCBs, but sex showed no significant association. Overall, this study found that there was no increase in the levels of compounds with dioxin-like activity in a population living close to an MSWI, in agreement with the literature reviewed, for plants of recent construction using state-of-the-art technology.

The environmental and biosecurity characteristics of livestock carcass disposal methods: A review

Livestock mortalities represent a major waste stream within agriculture. Many different methods are used throughout the world to dispose of these mortalities; however within the European Union (EU) disposal options are limited by stringent legislation. The legal disposal options currently available to EU farmers (primarily rendering and incineration) are frequently negatively perceived on both practical and economic grounds. In this review, we assess the potential environment impacts and biosecurity risks associated with each of the main options used for disposal of livestock mortalities in the world and critically evaluate the justification for current EU regulations. Overall, we conclude that while current legislation intends to minimise the potential for on-farm pollution and the spread of infectious diseases (e.g. transmissible spongiform encephalopathies, bacterial pathogens), alternative technologies (e.g. bioreduction, anaerobic digestion) may provide a more cost-effective, practical and biosecure mechanism for carcass disposal as well as having a lower environmental footprint. Further social, environmental and economic research is therefore warranted to assess the holistic benefits of alternative approaches for carcass disposal in Europe, with an aim to provide policy-makers with robust knowledge to make informed decisions on future legislation.

Dioxins and Human Toxicity

The term dioxins usually refers to polychlorinated dibenzo-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). As 2,3,7,8-tetrachloro-dibenzo-p-dioxin (TCDD) has the highest toxic potential, the toxic potentials of other PCDDs and PCDFs are defined in comparison with it. Human exposure to dioxins can be environmental (background), occupational, or accidental pollution. In the human body, dioxins are in part metabolised and eliminated, and the rest is stored in body fat. People vary in their capacity to eliminate TCDD, but it is also dose-dependent; the elimination rate is much faster at higher than lower levels. The liver microsomal P4501A1 enzyme oxygenates lipophilic chemicals such as dioxins. It is encoded by the CYP1A1 gene. Cytosolic aryl hydrocarbon receptor (AhR) mediates their carcinogenic action. It binds to dioxin, translocates to nucleus and together with hydrocarbon nuclear translocator (ARNT) and xenobiotic responsive element (XRE) increases the expression of CYP1A1.

Dioxins are classified as known human carcinogens, but they also cause noncancerous effects like atherosclerosis, hypertension, and diabetes. Long-term exposures to dioxins cause disruption of the nervous, immune, reproductive, and endocrine system. Short-term exposure to high levels impairs the liver function and causes chloracne. The most sensitive population to dioxin exposure are the foetuses and infants.

A large number of health effects have been documented in the scientific literature, and they all place dioxins among the most toxic chemicals known to man.

Monitoring temporal trends in environmental levels of polychlorinated dibenzo-p-dioxins and dibenzofurans: results from a 10-year surveillance program of a hazardous waste incinerator

The only hazardous waste incinerator (HWI) in Spain has been operating in Constantí (Tarragona County, Catalonia) since 1999. Before its construction, a surveillance program was initiated to monitor the concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the neighborhood of the facility. In 2008, 40 soil and 40 vegetation samples were collected and PCDD/F levels determined. The median PCDD/F concentration in soil was 0.49 ng international toxic equivalents (I-TEQ)/kg. Although it meant a nonsignificant decrease of 44% with respect to the preoperational survey, important fluctuations of the levels of PCDD/Fs through time were found in some specific sites. Therefore, a new survey was performed 1 year later (2009) by deleting those sampling sites with inconstant values, which mostly coincided with urban zones. In 2009, the median level of PCDD/Fs in soils was found to be 0.42 ng I-TEQ/kg. In contrast, median PCDD/F levels in vegetation were 1.11 ng I-TEQ/kg, a significant increase compared with previous surveys (range of the median 0.21-0.25 ng I-TEQ/kg). However, this increase was uniformly observed in the entire sampling area, suggesting that lack of rainfall was a key parameter for decreasing plant dilution and wash-up of pollutants on vegetation. This indicates that in surveillance programs, information must be obtained from different sources because the use of a single compartment may yield significant misinterpretation when evaluating temporal trends of environmental pollutants. Human health risks derived from exposure to PCDD/Fs were also assessed for the local population. The results indicated that current concentrations of these contaminants do not pose any additional carcinogenic or noncarcinogenic risk for those people living near the HWI.

Application of self-organizing maps for PCDD/F pattern recognition of environmental and biological samples to evaluate the impact of a hazardous waste incinerator

Kohonen's self-organizing maps (SOM) is one of the most popular artificial neural network models. In this study, SOM were used to assess the potential relationships between polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) congener profiles in environmental (soil, herbage, and ambient air) and biological (plasma, adipose tissue, and breast milk) samples, and the emissions of a hazardous waste incinerator (HWI) in Spain. The visual examination of PCDD/F congener profiles of most environmental and biological samples did not allow finding out any differences between monitors. However, the global SOM analysis of environmental and biological samples showed that the weight of the PCDD/F stack emissions of the HWI on the environmental burden and on the exposure of the individuals living in the surroundings was not significant in relation to the background levels. The results confirmed the small influence of the HWI emissions of PCDD/Fs on the environment and the population living in the neighborhood.

Intake and body burden of dioxin-like compounds in Germany: the INES study

The human body burden of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dl-PCBs) and the dietary intake of dl-PCB were investigated in Germany. In total, 50 adults (between 14 and 60 years old) were recruited, and duplicate diet samples were collected over seven consecutive days from each participant. Blood samples were acquired from 48 participants. Seventeen PCDD/Fs and 12 dl-PCBs (non- and mono-ortho congeners) were measured in the blood, and all dl-PCBs were measured in duplicate diet portions. Daily intake via food was calculated by multiplying the measured concentrations by the consumption data. Median (95th percentile) concentrations in the blood (expressed as WHO-TEQ) for PCDD/Fs, non-ortho PCBs and mono-ortho PCBs were 10.1 (25.0) pg g(-1) lipid, 4.2 (14.9) pg g(-1) lipid and 4.5 (14.2) pg g(-1) lipid, respectively. The contribution of mono-ortho PCBs and non-ortho PCBs to total TEQ was 25% and 24%, respectively. For each study subject, median intake levels for seven consecutive days were calculated. From these data, the median (95th percentile) daily intake via food was 0.12 (0.32) pg TEQ kg(-1)b.w. for non-ortho congeners and 0.06 (0.12) pg TEQ kg(-1)b.w. for the mono-ortho congeners. PCB 126, PCB 118 and PCB 156 accounted for about 93% of the total PCB intake. Our study indicates that dl-PCB exposure in adults consuming a normal mixed diet is quite low at present in Germany. The median and maximum daily intake contributed to 10% and 25% to the tolerable daily intake recommended for total PCDD/Fs and dl-PCBs.

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.

Levels of PCDD/F in adipose tissue on non-occupationally exposed subjects living near a hazardous waste incinerator in Catalonia, Spain

The potential adverse effects on human health of hazardous waste incinerators (HWIs) are a subject of concern. The construction of the first and till now only HWI in Spain finished in 1999. In 2007, after approximately 9 years of regular operations in the facility, the concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) were determined by HRGC/HRMS in samples of adipose tissue of 15 autopsied subjects living in the area under potential impact of the HWI (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/F concentration in adipose tissue was 14.6 pg WHO-TEQ/g of fat (range: 3.3-55.4 pg WHO-TEQ/g of fat). It means significant changes (a reduction of 64% and an increase of 47%) in the mean PCDD/F levels in comparison to those found in 1998 and 2002: 40.1 and 9.9 pg WHO-TEQ/g of fat, respectively. Women showed higher levels of PCDD/F than men (23.8 vs 11.2 pg WHO-TEQ/g of fat). The increase in the last 5 years would not be directly attributable to exposure to PCDD/F emitted by the HWI, as other biological monitors such as human plasma and milk decreased during the same period.