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

Regulatory compliance of PCDD/F emissions by a municipal solid waste incinerator. A case study in Sant Adrià de Besòs, Catalonia, Spain

Despite incineration is an important emission source of toxic pollutants, such as heavy metals and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), it is still one of the most widely used methods for the management of municipal solid waste. The current paper summarizes the results of a 20-year follow-up study of the emissions of PCDD/Fs by a municipal solid waste incinerator (MSWI) in Sant Adrià de Besòs (Catalonia, Spain). Samples of ambient air, soils and herbage were periodically collected near the facility and the content of PCDD/Fs was analyzed. In the last (2017) survey, mean levels in soil were 3.60 ng WHO-TEQ/kg (range: 0.40-10.6), being considerably higher than the mean concentrations of PCDD/Fs in soil samples collected near other MSWIs in Catalonia. Moreover, air PCDD/F concentrations were even higher than those found in a previous (2014) survey, as they increased from 0.026 to 0.044 pg WHO-TEQ/m3. Ultimately, the PCDD/F exposure would be associated to a cancer risk (2.5 × 10-6) for the population living in the surrounding area. Globally, this information indicates that the MSWI of Sant Adrià de Besòs could have had a negative impact on the environment and potentially on public health, being an example of a possible inappropriate management for years. The application of Best Available Techniques to minimize the emission of PCDD/Fs and other chemicals is critical.

Sources, effects and present perspectives of heavy metals contamination: Soil, plants and human food chain

Heavy metal (HM) poisoning of agricultural soils poses a serious risk to plant life, human health, and global food supply. When HM levels in agricultural soils get to dangerous levels, it harms crop health and yield. Chromium (Cr), arsenic (As), nickel (Ni), cadmium (Cd), lead (Pb), mercury (Hg), zinc (Zn), and copper (Cu) are the main heavy metals. The environment contains these metals in varying degrees, such as in soil, food, water, and even the air. These substances damage plants and alter soil characteristics, which lowers crop yield. Crop types, growing circumstances, elemental toxicity, developmental stage, soil physical and chemical properties, and the presence and bioavailability of heavy metals (HMs) in the soil solution are some of the factors affecting the amount of HM toxicity in crops. By interfering with the normal structure and function of cellular components, HMs can impede various metabolic and developmental processes. Humans are exposed to numerous serious diseases by consuming these affected plant products. Exposure to certain metals can harm the kidneys, brain, intestines, lungs, liver, and other organs of the human body. This review assesses (1) contamination of heavy metals in soils through different sources, like anthropogenic and natural; (2) the effect on microorganisms and the chemical and physical properties of soil; (3) the effect on plants as well as crop production; and (4) entering the food chain and associated hazards to human health. Lastly, we identified certain research gaps and suggested further study. If people want to feel safe in their surroundings, there needs to be stringent regulation of the release of heavy metals into the environment.

Contamination level, spatial distribution, and sources of potentially toxic elements in indoor settled household dusts in Tehran, Iran

Tehran, the capital city of Iran, has been facing air pollution for several decades due to rapid urbanization, population growth, improper vehicle use, and the low quality of fuels. In this study, 31 indoor dust samples were collected passively from residential and commercial buildings located in the central and densely populated districts of the city. These samples were analyzed after preparation to measure the concentration of elements (As, Be, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Se, Sr, V, Zn). Statistical data analyses were employed to compare their relationship across various uses, variations, and for source identification. Geochemical indices of contamination factor (CF) and pollution load index (PLI) were utilized to evaluate the degree of contamination. The mean concentrations of Zn, Cu, and Pb (938, 206, and 176 µg g-1, respectively) are 6, 5, and 3 times higher than their mean values in worldwide urban soils. Additionally, Cd, Mo, and Ni showed concentrations about 1.5 times higher, while As, Co, Cr, Mn, and Sr fell within the range of reference soils. Be, V, and Sb displayed remarkably lower mean values. Building use did not significantly influence element levels in indoor deposited dust except for Pb and Zn. A comparison of indoor concentrations with previously published data for outdoor dusts revealed higher enrichments of Mo, Cu, Pb, and Ni, while As, Cd, and Zn showed lower enrichments in street dust samples. The order of CF values indicated Hg > Zn > Cd > Pb > Cu > As > Ni > Cr > Co > V. For Hg, Zn, Pb, Cd, and Cu, all or almost all samples exhibited very high contamination. PLI values were consistently higher than 1, indicating contamination in all samples. Multivariate statistical analysis and Tehran's specific geological location suggested that mafic-intermediate volcanic rocks are primary sources for Cr, Cu, Fe, and Ni (PC1). As, Pb, and V (PC2) were attributed to fossil fuel combustion in vehicles and residential buildings. Pb is a legacy metal remaining from the use of leaded gasoline, which was phased out in the 1990s. Zn (PC3) is derived from vehicle tires.

Exposure and Risk Assessment to Airborne dl-PCBs and Dioxins in the Population Living in the Neighborhood of a Cement Plant: A Pilot Study in the Valencian Region of Spain

Emissions from cement manufacturing facilities may increase health risks in nearby populations. For this reason, dioxin-like PCB (dl-PCB), polychlorinated dibenzo-p-dioxin (PCDD), and polychlorinated dibenzofuran (PCDF) concentrations in PM₁₀ samples were assessed in the vicinity of a cement manufacturing plant located in the Valencian Region (eastern Spain). The total concentrations of the sum of dl-PCBs, PCDDs, and PCDFs ranged between 1.85 and 42.53 fg TEQ/m³ at the assessed stations. The average daily inhalation dose (DID) for the sum in adults ranged from 8.93 · 10^-4 to 3.75 · 10^-3 pg WHO TEQ kg^-1 b.w. d^-1, and, for children, the DID ranged from 2.01 · 10^-3 to 8.44 · 10^-3 pg WHO TEQ kg^-1 b.w. d^-1. Risk assessment for adults and children was performed using both daily and chronic exposure. The hazard quotient (HQ) was calculated considering 0.025 pg WHO TEQ kg^-1 b.w. d^-1 to be the acceptable maximum permitted inhalation exposure. The HQ obtained was slightly higher than 1 for PCDD/Fs at one of the stations (Chiva), indicating a possible health risk for the population under study due to inhalation exposure. In the case of chronic exposure, cancer risk (>10^-6) was observed for some samples in one of the assessed sampling sites (Chiva).

Multiple-criteria decision analysis to substantiate the prospects of industrial and solid municipal wastes as slurry fuel components

This article investigates the recovery of typical wastes (coal slime, sawdust, cardboard and tire pyrolysis residue) as part of high-moisture slurry fuels. Using a laboratory furnace, the ignition and combustion characteristics of fuels as well as NO_x and SO_x emissions were determined. Using multiple-criteria decision-making (MCDM) methods and experimental results, we access the performance of four different slurry fuels in comparison with bituminous coal. The novelty of the study is based on the following features: we consider a unique set of parameters of the fuels (economic, environmental, safety and energy indicators), as well as three countries for their potential use (the USA, India and Russia); three different methods for calculating the efficiency indicator of each fuel were used. Despite rather low energy performance, the summarizing efficiency indicator of waste-based slurries was 53-93% higher than that of coal. The use of cardboard in the composition of a fuel blend showed the best complex result (the increase in the efficiency indicator was 80-93% relative to coal). The least promising additive was the pyrolysis residue of automobile tires. Its addition resulted in a 10-15% decrease in overall efficiency relative to a slurry without additives. The research results are useful for optimizing the component composition of waste-based slurries, technical and economic development of projects for the incineration of various wastes in the form of high-moisture fuel slurries.

Landscape composition and inorganic contaminants in water and muscle tissue of Plagioscion squamosissimus in the Araguari River (Amazon, Brazil)

Amazonian aquatic environments are seriously impacted by dam-building and deforestation, among other threats. Therefore, the present study aimed to examine water quality in the middle and lower course of the Araguari River with respect to the composition of vegetative cover and the concentration of As, Cd and Hg in order to determine risks to the preservation of biota and risks to human health from consumption of P. squamosissimus contaminated with these inorganic elements. To accomplish this, water samples and fish specimens were collected in the middle and lower Araguari River in 2019. The concentration of inorganic contaminants was analyzed by atomic absorption spectrophotometry. These stretches of the Araguari River presented higher proportions of forest fragments and evident expansion of buffalo pastures. According to Brazilian legislation, the concentrations of Cd and Hg in the water samples represented risk quotient values > 1, indicating risk to the preservation of aquatic biota. In particular, the concentrations of Cd in the muscle tissue of P. squamosissimus in the lower Araguari River also indicated risks to human health. The bioaccumulation factor indicated that Hg is bioavailable in the water. It can be concluded that water imbalances in the middle and lower Araguari River compromise the health of both aquatic and human life.

Environmental levels and human health risks of metals and PCDD/Fs near cement plants co-processing alternative fuels in Catalonia, NE Spain: a mini-review

This paper was aimed at reviewing recent studies related with the impact on environment and human health of metals and PCDD/Fs near cement plants. It has been particularly focused on the impact of cement plants located in Catalonia, Spain, which have been monitored by our research for more than ten years. Environmental monitoring studies were performed under different cement plant conditions. While some of our studies examined temporal trends of the levels of the above indicated pollutants, the main goal of other surveys was to assess the impact of implementing alternative fuels in the facilities. Even one of the studies was performed before and after the cement plant temporally ceased its industrial activity. The impact of cement plants burning alternative fuels on the emissions of metals and PCDD/Fs elsewhere was also reviewed. Regarding the cement plants in Catalonia, no significant differences were found, neither in the long-term follow-up studies, nor when alternative fuels are used, nor when a cement plant temporally stopped its activity. These results are in agreement with those reported for several stack emissions of other cement plants working under different conditions. We conclude that emissions of metals and PCDD/Fs by cement plants working with the best available techniques (BAT), should not cause a significant negative impact neither on the surrounding environment, nor on the human health of the population living in the neighborhood.

Multiple classes of chemical contaminants in soil from an e-waste disposal site in China: Occurrence and spatial distribution

E-waste recycling is well known for releasing halogenated organic compounds (HOCs) and heavy metals. This study investigated the occurrence and distribution of traditional and novel classes of contaminants, including chlorinated, brominated, and mixed halogenated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs, PBDD/Fs, PXDD/Fs), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs) and polyhalogenated carbazoles (PHCZs), in soil from an e-waste disposal site in Hangzhou. PBDEs were the most abundant, at 343-69306 ng kg^-1, followed by PHCZs (896-41,362 ng kg^-1), PCDD/Fs (349-19,396 ng kg^-1), PCBs (51.3-1834 ng kg^-1), PBDD/Fs (2.99-524 ng kg^-1) and PXDD/Fs (0.104-21.2 ng kg^-1). The detected target compound concentrations were generally lower than those reported in the literature for informal e-waste sites. Nevertheless, they can serve as a basis of information for evaluation and subsequent control. The toxic equivalent (TEQ) contributions from these contaminants (except PBDEs) decreased as follows: PCDD/Fs > PXDD/Fs > PHCZs > PCBs > PBDD/Fs. ΣDioxins (PCDD/Fs + PBDD/Fs + PXDD/Fs) accounted for 47.7%-97.2% of the total TEQs in the soil. OCDD, 1,2,3,4,6,7,8-HpBDF and OBDF were the dominant congeners, mainly derived from combustion and transport because of their low saturated vapor pressure. PXDFs were more abundant than PXDDs, and homologue profiles suggested a similar formation mechanism for PXDFs and PBDFs involving successive Br-to-Cl exchange. PHCZs were reported in soil from an e-waste disposal area for the first time, and their concentrations were several orders of magnitude higher than those of the other contaminants. Although the risk of human exposure in this study was estimated to be lower than the values recommended by the WHO (1-4 pg TEQ/kg bw/day), health implications still exist, and further investigations are necessary.

Trends of Polychlorinated Compounds in the Surroundings of a Municipal Solid Waste Incinerator in Mataró (Catalonia, Spain): Assessing Health Risks

Since 2008, the environmental levels of polychlorinated compounds near a municipal solid waste incinerator in Mataró (Catalonia, Spain) have been periodically monitored. The present study aimed at updating the data regarding the temporal changes occurred between 2015 and 2017, when air and soil samples were collected again, and the concentrations of the same chemical pollutants (i.e., polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and polychlorinated biphenyls (PCBs)) were analysed. Furthermore, the health risks associated with their human exposure were also evaluated. The levels of all the contaminants in soil were far below the threshold established by regional and national legislations, also being lower than those observed in previous surveys. A similar trend was also noted for PCDD/Fs in air samples, while airborne PCBs were the only group of chemicals whose levels significantly increased. In any case, the global assessment of the data regarding the different pollutants and matrices indicates that there has not been a general increase in the environmental pollution around the facility. In addition, the environmental exposure to PCDD/Fs and PCBs by the population living nearby is still clearly lower than the dietary intake of these same chemical pollutants.

Human exposure to trace elements and PCDD/Fs around a hazardous waste landfill in Catalonia (Spain)

Hazardous waste landfills (HWLs) usually mean the end of non-reusable, non-recyclable and non-recoverable wastes derived from industrial activities. A number of hazardous compounds and toxic elements, such as PCDD/Fs, Cd, Cr, Hg, Pb and As, is associated to these wastes. The HWL of Castellolí (Catalonia, Spain) treats a variety of hazardous wastes, which include bottom ashes from waste incinerators and asbestos potentially containing those toxicants. In 2007, our group began a surveillance program inside the HWL and in nearby villages focused on assessing the environmental levels of PCDD/Fs and toxic elements. Here we summarize the most updated results, corresponding to data from samples collected between 2015 and 2018. The levels of most trace elements (As, Cd, Cr, Ni and Pb) in soils, as well as those of Cd and Pb in air, were significantly higher (p < 0.01) inside the HWL than outside. However, no relevant differences were noted in the concentrations of trace elements when comparing the results of villages near the HWL with those located farther. With respect to PCDD/Fs, a progressive decrease was observed between the first (2007) and most recent (2018) surveys. The human health risks associated with the exposure to trace elements and PCDD/Fs exposure were within acceptable ranges according to national and international legislations (HQ < 1 and Cancer risk < 10^-5).

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.