Framework for risk assessment of PFAS utilizing experimental studies and in-silico models.

Perfluoroalkyl substances (PFAS), especially PFOS and PFOA, are two widely used synthetic chemicals that can impact human health based on evidence from animal and epidemiologic studies. In this paper, we have reviewed and summarized the influence of PFAS exposure on health, pointing the quality of evidence, and applied translational techniques to integrate evidence for PFAS policy making. This is the first review where highly referred articles on PFAS used for policymaking by several regulatory agencies were collected and evaluated based on the review guidelines developed by the US National Toxicology Program's Office of Health Assessment and Translation (OHAT) review guidelines. Several limitations were observed, including co-exposure to multiple chemicals and limited measurement of primary and secondary outcomes related to specific toxicity. However, data from all the studies provided a moderate to strong level of confidence for link between PFAS exposure and different adverse outcomes. Secondly, for translating the risk to humans, an in-silico model and scaling approach was utilized. Physiologically based pharmacokinetic model (PBPK) was used to calculate the human equivalent dose (HED) from two widely accepted studies and compared with tolerable daily intakes (TDIs) established by various regulatory agencies. Inter-species dose extrapolation was done to compare with human the relevance of dosing scenarios used in animals. Overall, a framework for translation of risk was proposed based on the conclusions of this review with the goal of improving policymaking. The current paper can improve the methodological protocols for PFAS experimental studies and encourage the utilization of in-silico models for translating risk.

Risk Assessment of Perfluorooctane Sulfonate (PFOS) using Dynamic Age Dependent Physiologically based Pharmacokinetic Model (PBPK) across Human Lifetime.

The widespread use of Perfluorooctane sulfonate (PFOS) in everyday life, its long half-life, and the lipophilicity that makes it easily accumulate in the body, raises the question of its safe exposure among different population groups. There are currently enough epidemiological studies showing evidence of PFOS exposure and its associated adverse effects on humans. Moreover, it is already known that physiological changes along with age e.g. organ volume, renal blood flow, cardiac output and albumin concentrations affect chemicals body burden. Human biomonitoring cohort studies have reported PFOS concentrations in blood and autopsy tissue data with PFOS present in sensitive organs across all human lifespan. However, to interpret such biomonitoring data in the context of chemical risk assessment, it is necessary to have a mechanistic framework that explains show the physiological changes across age affects the concentration of chemical inside different tissues of the human body. PBPK model is widely and successfully used in the field of risk assessment. The objective of this manuscript is to develop a dynamic age-dependent PBPK model as an extension of the previously published adult PFOS model and utilize this model to predict and compare the PFOS tissue distribution and plasma concentration across different age groups. Different cohort study data were used for exposure dose reconstruction and evaluation of time-dependent concentration in sensitive organs. Predicted plasma concentration followed trends observed in biomonitoring data and model predictions showed the increased disposition of PFOS in the geriatric population. PFOS model is sensitive to parameters governing renal resorption and elimination across all ages, which is related to PFOS half-life in humans. This model provides an effective framework for improving the quantitative risk assessment of PFOS throughout the human lifetime, particularly in susceptible age groups. The dynamic age-dependent PBPK model provides a step forward for developing such kind of dynamic model for other perfluoroalkyl substances.

Air quality, health impacts and burden of disease due to air pollution (PM10, PM2.5, NO2 and O3): Application of AirQ+ model to the Camp de Tarragona County (Catalonia, Spain).

The purpose of this study was to assess the impact to human health of air pollutants, through the integration of different technics: data statistics (spatial and temporal trends), population attributable fraction using AIRQ+ model developed by the WHO, and burden of disease using Disability-Adjusted Life Years (DALYs). The levels of SO2, NO, NO2, O3, H2S, benzene, PM10, PM2.5, CO, benzo(a)pyrene and metals, obtained between 2005 and 2017 from the air quality monitoring network across Camp de Tarragona County, were temporally and spatially determined. Health impacts were evaluated using the AIRQ+ model. Finally, the burden of disease was assessed through the calculation of Years of Lost life (YLL) and Years Lost due to Disability (YLD). In general terms, air quality was good according to European quality standards, but it did not fulfil the WHO guidelines, especially for O3, PM10 and PM2.5. Several decreasing (NO, NO2, SO2, PM10 and benzene) and an increasing (O3) temporal trend were found. Correlation between unemployment rate and air pollutant levels was found, pointing that the economic crisis (2008-2014) was a factor influencing the air pollutant levels. Reduction of air pollutant levels (PM2.5) to WHO guidelines in the Camp de Tarragona County would decrease the adult mortality between 23 and 297 cases per year, which means between 0.5 and 7% of all mortality in the area. In this County, for lung cancer, ischemic heart disease, stroke, and chronic obstructive pulmonary disease due to levels of PM2.5 above the WHO threshold limits, DAYLs were 240 years. This means around 80 DALYs for 100,000 persons every year -between 2005 and 2017. Population attributable fraction (PAF) and burden of disease (DALYs) methodologies are suitable tools for regional and national policymakers, who must take decisions to prevent and to control air pollution and to analyse the cost-effectiveness of interventions.

Characterization and risk assessment of total suspended particles (TSP) and fine particles (PM2.5) in a rural transformational e-waste recycling region of Southern China.

In 2016, total suspended particles (TSP) and fine particles (PM2.5) were collected near four e-waste recycling parks in a region of Southern China. TSP and PM2.5 levels and composition around these industrial activities were determined and the potential risks for human health due to the exposure to toxic elements contained on fine particles (PM2.5) were evaluated. Levels of TSP and PM2.5 were lower with advanced recycling methods than with small recycling e-waste workshops operating in the sampling region. The main trace elements in particles were Cu, Pb, and Ti, the same as those detected before the transition to advanced dismantling methods in e-waste recycling. Significantly higher levels of Cu, Pb, Sn, Te, Tl and NH4+ in TSP and Cu and Te in PM2.5 were found in e-waste recycling areas than in BG site. Taking Cu as the indicative element emitted from e-waste recycling activities, significant high positive correlations between Cu and W, and Cu and Te were found. These elements are present and can be released from electrical and electronical components during e-waste recycling processes. Exposure to elements for the population living near these e-waste recycling parks means carcinogenic risks above the acceptable threshold (>10-5).

Seasonal characterization and dosimetry-assisted risk assessment of indoor particulate matter (PM10-2.5, PM2.5-0.25, and PM0.25) collected in different schools.

Inhalation of particulate matter (PM) has been linked to serious adverse health effects, such as asthma, cardiovascular diseases and lung cancer. In the present study, coarse (PM10-2.5), accumulation mode (PM2.5-0.25), and quasi-ultrafine (PM0.25) particulates were collected inside twelve educative centers of Tarragona County (Catalonia, Spain) during two seasons (cold and warm). Chemical characterization of PM, as well as risk assessment were subsequently conducted in order to evaluate respiratory and digestive risks during school time for children. Levels and chemical composition of PM were very different among the 12 centers. Average PM levels were higher during the cold season, as well as the concentrations of most toxic metals. In most schools, PM levels were below the daily PM10 threshold established in the regulation (50 µg/m3), with the exception of school number 1 during the cold season. On average, and regardless of season, coarse PM was highly influenced by mineral matter, while organic matter and elemental carbon were prevalent in quasi-ultrafine PM. The concentrations of the toxic elements considered by the legislation (As, Cd, Pb, and Ni) were below their correspondent regulatory annual limits. Calculated risks were below the safety thresholds, being fine fractions (PM2.5-0.25 and PM0.25) the main contributors to both digestive and respiratory risks.

Development of a human physiologically based pharmacokinetic (PBPK) model for phthalate (DEHP) and its metabolites: A bottom up modeling approach.

DEHP exposure to human comes from different sources such as food, diet, cosmetics, toys, medical products, and food wraps. Recently, DEHP was categorized as non-persistent endocrine disrupting compounds (EDCs) by the world health organization (WHO). Rat experimental studies showed that phthalate and its metabolite(s) can cause hepatic, developmental and reproductive toxicity. In human, DEHP rapidly metabolizes into a toxic metabolite MEHP. This MEHP further metabolizes into the different chemical forms of 5OH-MEHP, 5oxo-MEHP, 5cx-MEPP and phthalic acid. A simple DEHP pharmacokinetics model has been developed, but with a limited number of metabolites. A chemical like DEHP which extensively metabolised indicate the need of a detail metabolic kinetics study. A physiological based pharmacokinetics (PBPK) model of the DEHP considering all the major metabolites in human, has not been developed yet. The objective of this study is to develop a detailed human PBPK model for the DEHP and its major metabolites by using a bottom-up modelling approach with the integration of a in vitro metabolic data. This approach uses an in-vitro-in-vivo extrapolation (IVIVE) and a quantitative structure-activity relationship (QSAR) method for the parameterization of the model. Monte Carlo simulations were performed to estimate the impact of parametric uncertainty onto the model predictions. First, the model was calibrated using the control human kinetic study that represents the time course of DEHP metabolites concentration in both the blood and the urine. Then, the model was evaluated against the published independent data on different dosing scenarios. The results of model predictions for the DEHP metabolites in both the blood and the urine were well within the range of experimentally observed data. The model also captured the similar trend of time course profile to the observed data, shows model good predictability power. The current developed PBPK model can futher be used for the prediction of the time course of chemical concentrations for the different exposure scenarios not only in the blood and the urine but also in the other compartments. Moreover, this model can also be used to explore different biomonitoring studies for the human health risk assessment and might be useful for integrative toxicological study in improving exposure-target tissue dose-response relationship.

Partial replacement of fossil fuels in a cement plant: Assessment of human health risks by metals, metalloids and PCDD/Fs.

In 2009, a cement plant located in Alcanar (South Catalonia, Spain) started co-processing a special kind of refuse-derived fuel (RDF) called ENERFUEL™. In April 2014 and 2017, 5 and 8 years after RDF co-processing, the concentrations of metals and metalloids (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sb, Tl, V and Zn) and PCDD/Fs were measured in samples of soils, herbage and air collected in the vicinity of the facility. The comparison of the current concentrations with those obtained in a baseline study (2008), when fossil fuels were used solely, has shown that the environmental concentrations of metals, metalloids and PCDD/Fs were not significantly modified. The concentrations of metals, metalloids and PCDD/Fs in soil, vegetation and air of Alcanar are in the low part of the ranges found around other cement plants in Catalonia (in general, below 50th percentile). Non-carcinogenic risks due to exposure to metals, metalloids and PCDD/Fs were lower than the safety value (HQ<1). In turn, carcinogenic risks were below the 10-5 Spanish threshold. The present results corroborate that, from an environmental point of view, the use of wastes as alternative fuels (AF) in a cement plant, which is operating with suitable technical conditions, is a good option for waste management. It contributes towards overcoming challenges such as climate change and fossil fuel depletion, while utilizing principles of circular economy.

Temporal trend in the levels of polycyclic aromatic hydrocarbons emitted in a big tire landfill fire in Spain: Risk assessment for human health.

In May 2016, a big fire occurred in an illegal landfill placed in Seseña (Toledo, Spain), where between 70,000 and 90,000 tons of tires had been accumulated during years. Just after the fire, and because of the increase of airborne PAHs, we found that cancer risks for the population living in the neighborhood of the landfill were 3-5 times higher than for the rest of inhabitants of Seseña. Some months after our initial (June 2016) study, two sampling campaigns (December 2016 and May 2017) were performed to assess the temporal trends of the environmental levels of PAHs, as well as to reassure that these chemicals did not pose any risk for the human health of Seseña inhabitants. In soils, the total concentrations of the 16 PAHs (December 2016), as well as the sum of the seven carcinogenic PAHs, showed values between 8.5 and 94.7 ng g-1 and between 1.0 and 42.3 ng g-1, respectively. In May 2017, a significant decrease (between 4 and 38 times) in the levels of PAHs in air was observed, with total concentrations ranging between 3.49 and 5.06 ng m-3. One year after the fire, the cancer risk at different zones of Seseña was similar, being lower than that found in June 2016, and negligible according to national and international agencies.

Health risks of environmental exposure to metals and herbicides in the Pardo River, Brazil.

Mixture of metals and herbicides in rivers may pose relevant risks for the health of surrounding communities. Humans may be exposed to river pollution through intake of contaminated water and fish, as well as irrigated agricultural products. The aim of this study was to assess the human health risks of environmental exposure to metals and herbicides through water and fish intake in the Pardo River. Metals (Al, As, Be, Cd, Cr, Cu, Pb, Mn, Hg, Ni, Tl, Sn, V, and Zn) were analyzed in river water and in edible fish. Herbicides (ametryn, atrazine, diuron, hexazinone, simazine, and tebuthiuron) were analyzed in river water. Seasonal variances were also studied. Aluminum, Cd, Cu, Mn, Pb, and Zn levels in river water were higher than the USEPA benchmarks. Non-carcinogenic risks due to pollutants mixture exposure were above the limit, and carcinogenic risks of As exposure were >10-6 in the sampling points during the rainy season. Metal levels in fish were lower than the Brazilian legislation and do not pose a threat to public health. Herbicides were detected in four sampling points, with atrazine concentrations (range 0.16-0.32 µg/L) below the Brazilian standard (2.0 µg/L), but above the European Union standard (0.1 µg/L). Considering the water supply needs of cities located in the Pardo River Basin and the persistence of metals and herbicides, the present study indicated that there was a seasonal influence on non-carcinogenic and carcinogenic risks to human health, especially in the rainy season. Studies for water treatment plants implantation should consider the risks of exposure to persistent substances, in order to protect the population.

Environmental trends of metals and PCDD/Fs around a cement plant after alternative fuel implementation: human health risk assessment.

This study aimed at evaluating the potential impact of a cement plant after 4 years of the employment of alternative fuel. In June 2015, concentrations of PCDD/Fs and metals were determined in soils, vegetation and air in order to measure potential changes with respect to previous surveys before (July 2011) and after (June 2013) the employment of alternative fuel. Risks to human health were also assessed. In soils, metal levels were similar to those observed in June 2013 (p > 0.05). In comparison with July 2011, the increment was only statistically significant for As and Cd (p < 0.05). A notable increase in levels of PCDD/Fs was noted when current levels in soils (1.14 ng WHO-TEQ per kg) were compared with those observed in July 2011 (0.37 ng WHO-TEQ per kg) (p > 0.05) and June 2013 (0.41 ng WHO-TEQ per kg) (p < 0.05). This increase was mainly caused by the increase in PCDD/F levels at one sampling site, which showed the heterogeneity of PCDD/F levels in soils, possibly as a result of different point emissions over the years. On the other hand, temporal trends in levels of metals and PCDD/Fs in vegetation showed a clear decrease, which indicated that the particle fraction of these pollutants would potentially be removed from leaf surfaces by wash-off. In air, levels were similar to those found in previous surveys. The results of PCA showed that the change in fuel had not affected the environmental profiles of metals and PCDD/Fs around the cement plant. The exposure of the population living in the surroundings of the plant was measured and it was shown that diet was the major contributor for both metals and PCDD/Fs, with percentages of over 97%, the only exceptions being As and Pb, for which dietary intake accounted for 43% and 71% of the total exposure, respectively. Environmental non-cancer and cancer risks were within the limits considered as acceptable by international standards.

Alternative Fuel Implementation in a Cement Plant: Human Health Risks and Economical Valuation.

In June 2010, the cement plant of Montcada i Reixac (MR) (Catalonia, Spain) began a gradual implementation of alternative fuel to replace fossil fuel. Between December 2010 and November 2014, we conducted three monitoring surveys to evaluate the state of the environment around the facility. Data were compared with results from three monitoring surveys performed in 2008-2009. In all these studies, samples of soil, vegetation, and air were collected, being the content of a number of trace elements and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in these matrices determined. In general terms, a decrease of metal and PCDD/F concentrations was found. Human health risks followed a similar temporal trend, being acceptable according to national and international standards and independent on the fuel used. The Disability-Adjusted Life Year and the costs of cancer cases were also estimated for the population living around the MR cement plant, accounting for 4 years and 31,000 €/year, respectively.

Presence of PAHs in water and sediments of the Colombian Cauca River during heavy rain episodes, and implications for risk assessment.

In Colombia little attention has been paid to river pollution with Polycyclic Aromatic Hydrocarbons (PAHs). Low environmental control and legislation in such emerging region could significantly contribute to high PAHs releases. In this study, we report the presence of PAHs in water and sediments of the Cauca River (Colombia). Three sampling campaigns were carried out between May 2010 and June 2011, and the samples were collected at eight relevant sites. The sampling time included measuring before, during, and after a season of heavy rains, which were influenced by the global coupled ocean-atmospheric phenomenon, which affected tropical countries with huge flooding, commonly called "La Niña", and/or "El Niño" Southern Oscillation (ENSO). The highest mean ∑PAH concentrations were 4476.5 ng/l and 1582.7 ng/g in water and sediments, respectively. The PAHs most detected were Benzo[b]fluoranthene, Benzo[k]fluoranthene, and Pyrene in sediments; and Fluorene, Acenaphtylene, and Anthracene in water. After the season of rains statistically significant higher PAH concentrations were detected. The results of the study were compared to other rivers worldwide at both environmental compartments, and did not show concentrations of special concern. In some sites, concentrations detected of PAHs were higher than screening benchmarks for ecological protection. Estimation of human health risks was carried out, and the results suggested some likely carcinogenic effects due to PAHs especially in children exposed during current recreational swimming and adults working in low technology sand extraction.

Ecotoxicity of sediments in rivers: Invertebrate community, toxicity bioassays and the toxic unit approach as complementary assessment tools.

The determination of the real toxicity of sediments in aquatic ecosystems is challenging and necessary for an appropriate risk assessment. Different approaches have been developed and applied over the last several decades. Currently, the joint implementation of chemical, ecological and toxicological tools is recommended for an appropriate and successful toxicity risk assessment. We chose the combination of the toxic unit approach with acute pore water tests (Vibrio fischeri, Pseudokirchneriella subcapitata and Daphnia magna) and whole-sediment exposure tests (V. fischeri, Chironomus riparius), together with invertebrate community composition (multivariate analyses) to detect short and long-term responses of the organisms in four rivers of the Iberian Peninsula. High toxicity was detected in three sites (the downstream sites of the Llobregat and the Júcar, and the most upstream site of the Ebro). We identified organophosphate insecticides and metals as the main variables responsible for this toxicity, particularly in the whole-sediment tests. In particular, chlorpyrifos was mostly responsible for the toxicity (TUs) of D. magna, coinciding with the C. riparius mortality (long-term toxicity) in the mentioned sites, and copper was the main pollutant responsible for the short-term toxicity of P. subcapitata. The combination of the different approaches allowed us to detect ecotoxicological effects in organisms and identify the main contributors to the toxicity in these multi-stressed rivers.

Temporal trends in the levels of metals, PCDD/Fs and PCBs in the vicinity of a municipal solid waste incinerator. Preliminary assessment of human health risks.

The concentrations of PCDD/Fs, PCBs, and metals were determined in soil and air samples collected near a municipal solid waste incinerator (MSWI) located in Mataró (Catalonia, Spain), being the health risks for the population living in the vicinity of the facility subsequently assessed. We also established the temporal trends with respect to previous surveys performed in the same zone. In general terms, the highest environmental levels of the pollutants were found in the city of Mataró and were independent on the distance to the MSWI. Soil levels of metals did not show temporal variations between the current and previous campaigns. However, the concentrations of metals in air samples collected in 2011 and 2013, were lower than those found in our 2008 survey. Regarding PCDD/Fs and PCBs, no differences were noted between the levels of the current survey and those corresponding to 2008. Anyhow, the concentrations of metals, PCDD/Fs, and PCBs in soils and air did not exceed the reference values established by regulatory organizations, being also in the low range of other similar studies recently reported. Finally, the human non-carcinogenic and carcinogenic risks due to exposure to metals, PCDD/Fs, and PCBs, were, for the population living in the neighborhood of the MSWI, considered as acceptable according to international standards.

Human exposure to trace elements through the skin by direct contact with clothing: Risk assessment.

Metals in textile products and clothing are used for many purposes, such as metal complex dyes, pigments, mordant, catalyst in synthetic fabrics manufacture, synergists of flame retardants, antimicrobials, or as water repellents and odour-preventive agents. When present in textile materials, heavy metals may mean a potential danger to human health. In the present study, the concentrations of a number of elements (Al, As, B, Ba, Be, Bi, Cd, Co, Cr, Cu, Fe, Hg, Mg, Mn, Mo, Ni, Pb, Sb, Sc, Se, Sm, Sn, Sr, Tl, V, and Zn) were determined in skin-contact clothes. Analysed clothes were made of different materials, colours, and brands. Interestingly, we found high levels of Cr in polyamide dark clothes (605 mg/kg), high Sb concentrations in polyester clothes (141 mg/kg), and great Cu levels in some green cotton fabrics (around 280 mg/kg). Dermal contact exposure and human health risks for adult males, adult females, and for <1-year-old children were assessed. Non-carcinogenic and carcinogenic risks were below safe (HQ<1) and acceptable (<10(-6)) limits, respectively, according to international standards. However, for Sb, non-carcinogenic risk was above 10% of the safety limit (HQ>0.1) for dermal contact with clothes.

Assessment of sediment ecotoxicological status as a complementary tool for the evaluation of surface water quality: the Ebro river basin case study.

According to the European Water Framework Directive (WFD), assessment of surface water status is based on ecological and chemical status that is not always in coherence. In these situations, ecotoxicity tests could help to obtain a better characterization of the ecosystems. The general aim of this work is to design a methodology to study the ecotoxicological status of freshwater systems. This could be useful and complementary to ecological status, for a better ecological characterization of freshwater systems. For this purpose, sediments from thirteen sampling sites within the Ebro river watershed (NE Spain) were collected for ecotoxicity characterization. The ecotoxicity of pore water has been evaluated employing the test organisms Vibrio fischeri, Pseudokirschneriella subcapitata and Daphnia magna, while whole sediment ecotoxicity was evaluated using Vibrio fischeri, Daphnia magna, Nitzschia palea and Chironomus riparius. An analysis of acid-volatile sulfide (AVS) and simultaneously extracted metals (SEM) was performed to evaluate the sediment toxicity associated to bioavailable metals. Moreover, data about priority pollutants defined by the WFD in water, sediment and fish as well as data of surface water status of each sampling point were provided by the Monitoring and Control Program of the Ebro Water bodies. In general terms, whole sediment bioassays have shown more toxicity than pore water tests. Among the different organisms used, P. subcapitata and C. riparius were the most sensitive in pore water and whole sediment, respectively. Our evaluation of the ecotoxicological status showed high coincidences with the ecological status, established according to the WFD, especially when ecosystem disruption due to numerous stressors (presence of metals and organic pollution) was observed. These results allow us to confirm that, when chemical stressors affect the ecosystem functioning negatively, an ecotoxicological approach, provided by suitable bioassays in pore water and whole sediment, could detect these changes with accurate sensitivity.

Environmental concentrations of metals in the catalan stretch of the ebro river, Spain: assessment of temporal trends.

The aim of this study was to investigate the environmental impact and the human health risks associated with exposure to a number of metals before and after initiating the decontamination process in Flix dam (Catalonia, Spain). The concentrations of As, Cd, Cr, Cu, Mn, Hg, Ni, and Pb were determined in samples of drinking water, river water, and soils collected in the Catalan stretch of the Ebro River, Spain. The results were compared with those of previous surveys performed in the same zones. Human exposure to metals, as well as the associated carcinogenic and non-carcinogenic risks, was also estimated. In river and drinking waters, most analyzed metals showed increases, being significant that of Cr. The movements of polluted sludge in Flix dam could be the reason for the Cr levels found in the current survey. However, Hg was not detected in both drinking and river waters. Important differences on Mn levels were found, being higher those in river water than in drinking water. In turn, although soil concentrations of all analyzed metals showed a decreasing temporal trend, the reductions were only significant for Ni. The hazard quotient (HQ) of all elements was below the unity, considered the safe threshold. For carcinogenic risks, all values were found to be lower than 10(-5), which has been defined as the maximum recommended excess of cancer risk according to the Spanish Legislation. The only exception was the As exposure through soil and drinking water, which slightly exceeded this threshold. The current results indicate the need to perform a continuous assessment of metal levels not only in river waters, but also in drinking water in order to assure the harmlessness of the decontamination process for the health of the population living downriver (Ebro) the Flix dam.

Environmental levels of PCDD/Fs and metals around a cement plant in Catalonia, Spain, before and after alternative fuel implementation. Assessment of human health risks.

The concentrations of As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sb, Sn, Tl, V, and Zn, and the levels of polychlorinated dibenzo-p-dioxins and dibenzofurans were determined in samples of soil, vegetation, and air, collected in the vicinity of a cement plant (Catalonia, Spain), before (January 2011 and July 2011) and after (January 2012 and June 2013) alternative fuel partial substitution (fossil fuels by sewage sludge). Seven sampling points were selected at different directions and distances to the facility including two background sampling points. The results were used to assess the health risk assessment for the population living near the facility. Only few significant differences were found before and after alternative fuel partial substitution (Mn in soils and Cd in vegetation). Non-carcinogenic risks were below the safety threshold (HQ<1), while carcinogenic risks were below 10(-5), or exceeding slightly that value, always in the range considered as assumable (10(-6)-10(-4)).

Dynamic interactions between hydrogeological and exposure parameters in daily dose prediction under uncertainty and temporal variability.

We study the time dependent interaction between hydrogeological and exposure parameters in daily dose predictions due to exposure of humans to groundwater contamination. Dose predictions are treated stochastically to account for an incomplete hydrogeological and geochemical field characterization, and an incomplete knowledge of the physiological response. We used a nested Monte Carlo framework to account for uncertainty and variability arising from both hydrogeological and exposure variables. Our interest is in the temporal dynamics of the total dose and their effects on parametric uncertainty reduction. We illustrate the approach to a HCH (lindane) pollution problem at the Ebro River, Spain. The temporal distribution of lindane in the river water can have a strong impact in the evaluation of risk. The total dose displays a non-linear effect on different population cohorts, indicating the need to account for population variability. We then expand the concept of Comparative Information Yield Curves developed earlier (see de Barros et al. [29]) to evaluate parametric uncertainty reduction under temporally variable exposure dose. Results show that the importance of parametric uncertainty reduction varies according to the temporal dynamics of the lindane plume. The approach could be used for any chemical to aid decision makers to better allocate resources towards reducing uncertainty.

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.