Levels of dioxins and furans in urban surface soil in Trondheim, Norway

Generalized prediction and optimal operating parameters of PCDD/F emissions by explainable Bayesian support vector regression

The current derived models for predicting polychlorinated dibenzo-p-dioxins and -furans (PCDD/F) emissions from incineration can only be applied to a specific incinerator due to high deviation or systematic errors. And the models fail to provide quantized guidance for the operation of full-scale municipal solid waste incinerators. To address the problem, explainable Bayesian support vector regression (E-BSVR) has been established to generalized predict and maximumly reduce the PCDD/F emissions. First, forty-two PCDD/F samples were determined from a whole year experiment in a full-scale incinerator. Meanwhile, 1,2,4-trichlorobenzene(1,2,4-TrCBz), carbon monoxide, sulfur dioxide, oxynitride, particulate matter, fluoride, and hydrogen chloride were measured, as input features. Second, after box-cox transformation normalization, and hyperparameters tuning, the R-Squared and root mean square error (RMSE) of the proposed method are 0.983 and 0.044, exhibiting high accuracy. The high accuracy (R-Squared = 0.992) and generalization are also proven on the dataset with high PCDD/F emissions. Then, the performances of BSVR are compared with kernel ridge regression, multiple linear regression, and unary linear regression, indicating afar smaller RMSE of BSVR. Finally, the optimal operating parameters are calculated through local interpretable model-agnostic explanations and the partial dependence plot. Results indicate that reducing the content of organic chlorine in municipal solid waste and inhibiting the deacon reaction are important methods for reducing PCDD/F emissions. The optimal operating parameters for the maximal reduction of PCDD/F emissions are 1,2,4-TrCBz < 0.098 ug/m³, fluoride > 0.452 mg/m³. As a whole, the E-BSVR method can be used as a reliable and accurate approach for the prediction and reduction of PCDD/F emissions.

Spatial Outcomes of Soft Tissue Sarcoma in Southern West Virginia

Introduction Dioxins, polychlorinated biphenyls (PCBs), and 2,3,7,8-Tetrachlorodibenzodioxin (TCDDs) are persistent organic pollutants widely distributed in the food chain. For over 50 years, the Monsanto plant in Nitro, West Virginia, created dioxin waste while producing herbicides, Agent Orange (during the Vietnam War), and different forms of rubber. Recent and past literature has established a link between the Monsanto plant and increased cancer cases within the region. Soft tissue sarcoma is one of the few specific cancers that has been linked to dioxin exposure. This pilot study examined whether sarcoma cases were clustered or randomly distributed within Kanawha County, West Virginia over the years 2000 to 2013. We hypothesize that sarcoma cancer cases will be spatially clustered. Methods This study assessed the spatial distribution of cancer patients with addresses within the Nitro, West Virginia, and study area. The Charleston Area Medical Center shared soft tissue sarcoma (n = 97) cases from 2000 to 2013. An unweighted K function with confidence intervals (99 Monte Carlo permutations) and 10 distance at 2800 meters each band analyzed the distribution of cases. Results The results suggest that sarcoma cases are slightly clustered within the study area. The region also has a high concentration of chemical and industrial sites. The eighth distance band exhibited the greatest difference (11384), between the expected versus the observed K function. Conclusion The unweighted K function shows non-random clustering. Future studies could investigate possible associations to industrial, chemical, or other possible point source contamination within the study area.

Effect of different air pollution control devices on the gas/solid-phase distribution of PCDD/F in a full-scale municipal solid waste incinerator

The emission of polychlorinated dibenzo-p-dioxins and -furans (PCDD/F) from full-scale municipal solid waste incinerators (MSWI) is harmful to human and environmental health. This study analyzes the effect of different units of an air pollution control devices (APCDs), i.e. the semi-dry scrubber, fabric filter (FF), selective catalytic reduction (SCR), and wet scrubber (WS), on the removal characteristics and gas- and solid-phase distributions of PCDD/F in MSWI flue gas. APCDs reduce PCDD/F concentrations from 24.9 ng Nm^-3 to 0.979 ng Nm^-3 (2.16 ng I-TEQ Nm^-3 to 0.0607 ng I-TEQ Nm^-3), with a total removal efficiency (RE) of 96.1% (97.2% I-TEQ). Specifically, APCDs remove more than 95% of both gas- and solid-phase PCDD/F. The FF coupled with active carbon injection (FF + ACI) substantially reduces both gas- and solid-phase PCDD/F concentrations with an RE of 97.2% (98.7% I-TEQ). Additionally, FF + ACI exhibits a better RE of PCDF (98.9%) than PCDD (94.6%) and leads to PCDD congeners dominating the gas-phase. Both desorption and destruction of PCDD/F occur in the SCR, which favors removal of gas-phase PCDD/F but increases solid-phase PCDD/F. Therefore, SCR only decreases PCDD/F with a low RE of 27.6% (16.9% I-TEQ). However, SCR reduces NO_x with a high RE of 82.3%, which could inhibit the RE of PCDD/F because of their different reaction mechanisms. WS increases PCDD/F in both the gas and solid-phase by 1.95 times (2.57 times for I-TEQ) due to the memory effect, which typically increases the total mass concentration of PCDD/F and the proportions of lower-chlorinated gas-phase PCDD/F. Migration of gas- and solid-phase PCDD/F are also analyzed according to temperature. The results of this study can contribute to the optimized design of industrial APCDs for controlling PCDD/F emissions from MSWI.

Organochlorines in urban soils from Central India: probabilistic health hazard and risk implications to human population

This study presents distribution of organochlorines (OCs) including HCH, DDT and PCBs in urban soils, and their environmental and human health risk. Forty-eight soil samples were extracted using ultrasonication, cleaned with modified silica gel chromatography and analyzed by GC-ECD. The observed concentrations of ∑HCH, ∑DDT and ∑PCBs in soils ranged between < 0.01-2.54, 1.30-27.41 and < 0.01-62.8 µg kg^-1, respectively, which were lower than the recommended soil quality guidelines. Human health risk was estimated following recommended guidelines. Lifetime average daily dose (LADD), non-cancer risk or hazard quotient (HQ) and incremental lifetime cancer risk (ILCR) for humans due to individual and total OCs were estimated and presented. Estimated LADD were lower than acceptable daily intake and reference dose. Human health risk estimates were lower than safe limit of non-cancer risk (HQ < 1.0) and the acceptable distribution range of ILCR (10^-6-10^-4). Therefore, this study concluded that present levels of OCs (HCH, DDT and PCBs) in studied soils were low, and subsequently posed low health risk to human population in the study area.

Concentrations of trace elements and PCDD/Fs around a municipal solid waste incinerator in Girona (Catalonia, Spain). Human health risks for the population living in the neighborhood

Previously to the modernization of the municipal solid waste incinerator (MSWI) of Campdorà (Girona, Catalonia, Spain) two sampling campaigns (2015 and 2016) were conducted. In each campaign, 8 soil and 4 air samples (PM₁₀ and total particle phase and gas phase) were collected. The levels of As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sb, Sn, Tl and V, and PCDD/Fs were analysed at different distances and wind directions around the MSWI. Environmental levels of trace elements and PCDD/Fs were used to assess exposure and health risks (carcinogenic and non-carcinogenic) for the population living around the facility. In soils, no significant differences were observed for trace elements and PCDD/Fs between both campaigns. In air, significant higher levels of As, Cd, Co, Mn, Ni, Pb, Tl and V were detected in 2016. Regarding soil levels, only Cd (distances) and As, Cu, Mn, and Ni (wind directions) showed significant differences. No differences were noted in the concentrations of trace elements and PCDD/Fs in air levels with respect to distances and directions to the MSWI. No differences were registered in air levels (elements and PCDD/Fs) between points influenced by MSWI emissions and background point. However some differences in congener profile were noted regarding from where back-trajectories come from (HYSPLIT model results), pointing some influence of Barcelona metropolitan area. The concentrations of trace elements and PCDD/Fs were similar -or even lower- than those reported around other MSWIs in Catalonia and various countries. Non-carcinogenic risks were below the safety limit (HQ<1). In turn, carcinogenic risks due to exposure to trace elements and PCDD/Fs were in acceptable ranges, according to national and international standard regulations.

Probabilistic health risk assessment of polycyclic aromatic hydrocarbons and polychlorinated biphenyls in urban soils from a tropical city of India

Distribution of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in urban soils, and their risk for humans was evaluated and presented in this article. The average concentration of ∑16PAHs, ∑carcinogenic PAHs, ∑28PCBs and ∑dioxin-like PCBs was 631.6 ± 244.5 μg kg(-1), 568.8 ± 238.8 μg kg(-1), 11.57 ± 2.00 μg kg(-1) and 2.58 ± 0.34 μg kg(-1), respectively. Environmental and human health risk assessment parameters such as benzo(a)pyrene total potency equivalent (BaP TPE), index of additive cancer risk (IACR), life time average daily dose (LADD) and incremental lifetime cancer risk (ILCR) have been estimated and discussed. The average benzo(a)pyrene total potency equivalent (BaP TPE) estimate was 0.194 mg kg(-1) and ranging between 8.9×10(-4) to 0.87 mg kg(-1). The incremental life time cancer risk (ILCR) of PAHs through soil ingestion for adults and children was estimated as 8.1×10(-6) and 4.2×10(-5), respectively. However, the cancer risk (ILCR) from non-dioxin-like PCBs and dioxin-like PCBs for adults and children ranged between 3.31×10(-8) to 1.741×10(-7) and 1.46×10(-5) to 7.56×10(-5), respectively. These estimated risks were lower than acceptable limits, based on incremental cancer risk from soil exposure. Overall, index of additive cancer risk (IACR) and hazard quotient (HQ) for PAHs and PCBs was lower than safe limit of 1, indicating no environmental and human health risk from PAHs and PCBs in this area of study.

Long-term monitoring of dioxins and furans near a municipal solid waste incinerator: human health risks

Since 1996, a wide surveillance programme has been developed to get overall information on the impact of a municipal solid waste incinerator (MSWI) in Tarragona (Catalonia, Spain). The concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) have been periodically measured in soil and vegetation samples collected at locations in the incinerator surroundings. Furthermore, air PCDD/F levels have been also monitored by using active and passive sampling devices, generating a huge amount of information regarding the environmental status of the zone. In the last survey (2009-2010), mean PCDD/F levels in vegetation, soil and air were 0.06 ng I-TEQ kg(-1), 0.58 ng I-TEQ kg(-1) and 10.5 fg WHO-TEQ m(-3), respectively. Both soil and herbage showed a notable reduction in the PCDD/F concentrations in comparison with the baseline study, with this decrease only being significant for soils. In contrast, PCDD/F values in air remained similar during the whole assessment period. Human exposure to PCDD/Fs was evaluated under different scenarios, and the associated non-carcinogenic and carcinogenic risks were assessed. The hazard quotient was below unity in all cases, while cancer risks were under 10(-6), which is lower than the maximum recommended guidelines. The current results clearly show that the MSWI of Tarragona does not produce additional health risks for the population living nearby.

Baseline soil levels of PCDD/Fs established prior to the construction of municipal solid waste incinerators in China

In order to determine the baseline contamination by polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in different areas in China, prior to the construction of municipal solid waste incinerators (MSWIs), a total of 32 representative soil samples was collected near 16 incinerators and analyzed for their PCDD/F concentrations. The PCDD/F baseline concentrations in the soil samples ranged from 0.32 to 11.4 ng I-TEQ kg(-1) (dry matter), with average and median value of 2.73 and 2.24 ng I-TEQ kg(-1) (dry matter), respectively, and a span between maximum and minimum recorded value of 36. The PCDD homologues predominated in 26 out of 32 soil samples, with the ratio (PCDDs)/(PCDFs) ranging from 1.1 to 164; however in the other 6 samples, PCDF homologues were larger, with the same ratio varying from 0.04 to 0.8. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used to examine PCDD/F amount and profile in these soil samples, and their possible associations with known emission sources: in this process 6 really distinct isomer fingerprints were identified. Background PCDD/F levels and profiles were comparable to those found in soils from China and other countries and indicate a rather low baseline PCDD/F contamination of soils. The present data provide the tools for future assessment of a possible impact of these MSWIs.

PCDD/Fs in soil around a hospital waste incinerator: comparison after three years of operation

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) can be formed during the cooling of flue gases in waste incinerator. These pollutants are either in the gas phase or attached to the fine particles, escaping dust collection. After stack emission, they are slowly oxidized photochemically (gas phase), or eventually are deposited (dry and wet deposition of particulate) in earth surface. In 2007 and 2010, 11 soil samples were collected in the vicinity of a hospital waste incinerator (HWI), prior and after its startup. In order to find out any variation of PCDD/Fs in soil, in brief dioxins, their concentrations were analyzed by high-resolution gas chromatography with high-resolution mass spectrometry (HRGC/HRMS). Compared to the baseline survey (2007), PCDD/Fs in soil significantly increased, by average, +81.6% in total PCDD/Fs and +132.7% in international toxic equivalency (I-TEQ) unit. By principal component analysis (PCA), both the PCDD/Fs homologue and the HxCDF isomer profile in soil were found to become more similar with fly ash. Generally, this incinerator influences the soil only in a limited area. More comprehensive supervision, stricter management and more advanced technology should be implemented in this plant to reduce pollutants emission, even though the level of PCDD/Fs in soil is quite low at present.

PCDD/Fs atmospheric deposition fluxes and soil contamination close to a municipal solid waste incinerator

Bulk depositions and surface soil were collected in a suburban area, near the Adriatic Sea, in order to assess the contribution of a municipal solid waste incinerator to the area's total contamination with polychlorinated dibenzodioxins and polychlorinated dibenzofurans (PCDDs and PCDFs). Samples were collected at two sites, situated in the area most affected by plant emissions (according to the results of the Calpuff air dispersion model), and at an external site, considered as a reference. Results show that the studied area is subject to low contamination, as far as these compounds are concerned. Deposition fluxes range from 14.3 pg m(-2)d(-1) to 89.9 pg m(-2)d(-1) (0.75 pg-TEQ m(-2)d(-1) to 3.73 pg-TEQ m(-2)d(-1)) and no significant flow differences are observed among the three monitored sites. Total soil concentration amounts to 93.8 ng kg(-1) d.w. and 1.35 ng-TEQ kg(-1)d.w, on average, and confirms a strong homogeneity in the studied area. Furthermore, from 2006 to 2009, no PCDD/Fs enrichment in the soil was noticed. Comparing the relative congener distributions in environmental samples with those found in stack emissions from the incineration plant, significant differences are observed in the PCDD:PCDF ratio and in the contribution of the most chlorinated congeners. From this study we can conclude that the incineration plant is not the main source of PCDD/Fs in the studied area, which is apparently characterized by a homogeneous and widespread contamination situation, typical of an urban area.

Monitoring environmental pollutants in the vicinity of a cement plant: a temporal study

From 2008 to 2009, we evaluated the environmental impact of a cement plant (Montcada i Reixac, Catalonia, Spain) that is located close to densely populated areas. The potential health risks for the population living in the neighborhood were also assessed. The levels of various heavy metals and the concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were determined in soil, vegetation, and air samples collected at different directions and distances from the facility. Three 6-monthly consecutive campaigns were performed to establish temporal and seasonal trends. Multivariate statistical techniques, such as principal component analysis, were used. Human exposure to metals and PCDD/Fs, as well as the associated carcinogenic and noncarcinogenic risks, were also calculated. Environmental pollutant concentrations, especially those found in urban sites, were noted to be slightly higher than those recently reported around other cement plants in Catalonia. A seasonal pattern was observed, with higher values recorded during the colder sampling periods. Despite this, the carcinogenic and noncarcinogenic risks derived from human exposure to metals and PCDD/Fs were within the ranges considered acceptable by international regulatory organisms.

Levels of PCDD/Fs in agricultural soils near two municipal waste incinerators in Shanghai, China

A study was conducted on polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/F) in agricultural soils at 41 sites within a radius of 3 km from two municipal solid waste incinerators in Shanghai. The PCDD/F concentrations ranged from 71.32 to 3,881.44 pg g⁻¹ (0.64-61.15 pg I-TEQ g⁻¹). The highest PCDD/F concentrations were found approximately 1,000 m from the municipal solid waste incinerators. The PCDD/F homologue profiles of all soil samples were compared with the profiles from suspected PCDD/F sources by multivariate statistical analysis. The results showed that, the PCDD/F pollutions in some soil samples can be attributed to emissions from the municipal solid waste incinerators.

Levels of metals and PCDD/Fs in the vicinity of a cement plant: assessment of human health risks

In April 2009, a cement plant located in Sant Feliu de Llobregat (Catalonia, NE Spain) stopped its normal operations. To establish the environmental impact of the facility and the health risks for the population living in the neighbourhood, the concentrations of a number of metals and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were determined in soil, vegetation and air samples in three different surveys, which were carried out before and after the facility stopped the cement production. The influence of the cement plant was found to be low in comparison with other potential emission sources in the area, as no decrease in the immission concentrations was noted after the facility ceased its industrial activity. No significant differences were observed in human health risks derived from the exposure to metals and PCDD/Fs before and after the plant ceased the cement production. Risk values for the population living near the facility were similar to those found for residents living in a number of urban and suburban areas.

Dioxin-like chemicals in soil and sediment from residential and industrial areas in central South Africa

Persistent organic pollutants (POPs) are a global concern due to their ubiquitous presence and toxicity. Currently, there is a lack of information regarding POPs from South Africa. Here we report and interpret concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), -dibenzofurans (PCDFs) and co-planar-biphenyls (PCBs) in soils and sediments collected from central South Africa. High resolution gas chromatography-high resolution mass spectrometry (HRGC/HRMS) and the H4IIE-luc bio-assay were used to identify and quantify individual PCDD/F congeners and to report the total concentration of 2,3,7,8-tetrachloro dibenzo-p-dioxin equivalents (TCDD-EQ), respectively. TCDD-EQs determined by use of the bio-assay, and concentrations of WHO(2005)-TEQ (toxic equivalents) determined by chemical analysis, were similar. The limit of detection (LOD) for the bio-assay was 0.82 and 2.8 ng TCDD-EQ kg(-1), dw for sediment and soil, respectively. EQ20 concentrations determined by use of the bio-assay ranged from <LOD to 70 ng TCDD-EQ kg(-1), dw for soil, and from <LOD to 45 ng TCDD-EQ kg(-1), dw for sediment. Concentrations of WHO(2005)-TEQ in soils were generally greater than those in sediments, and soils from the industrial area of Vanderbijlpark and the residential area of Klerksdorp contained the greatest concentrations. Based on the congener-specific HRGC/HRMS analyzes, concentrations of WHO(2005)-TEQ ranged from 0.12 to 32 ng WHO(2005)-TEQ kg(-1), dw in sediments, and between 0.34 and 20 ng WHO(2005)-TEQkg(-1), dw in soils. The sources, processes and threats that govern and are associated with the lesser concentrations in sediment and greater concentrations in soils need further investigation.

Concentrations of PCDD/PCDFs and PCBs in spent foundry sands

Approximately 10 million tons of spent foundry sand (SFS) are generated in the United States each year, and their beneficial use in agricultural and horticultural applications is being considered. Other studies have demonstrated that trace elements are low enough in sands from iron, steel, and aluminum foundries to allow their beneficial use. Because data were not available on polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and polychlorinated biphenyls in SFSs, we analyzed representative spent sands from 10 foundries to assess the potential for these compounds to limit their use in soil-related applications. The total TEQ (toxicity equivalent) concentrations ranged from 0.01 to 3.13 ng TEQ kg(-1), with an average concentration of 0.58 ng TEQ kg(-1). These concentrations are within the range of natural background in soils.