Theoretical Health Risk Assessment Based on Potentially Toxic Element Profiling of Cosmetic Products in Istanbul Street Bazaars

Toxic elements that pose a potential threat to human health are found as impurities in various cosmetic products. In this study, the inorganic profile of 19 elements (Li, B, Mg, Al, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Sr, Mo, Cd, Sb, Ba, Hg, and Pb) in 90 cosmetic products (lipsticks, lip glosses, lip pencils and eye shadows) were detected by inductively coupled plasma-mass spectrometry after microwave acid digestion method and hazard indices (HI) of 9 toxic elements (Pb, Cd, Cr, Ni, Co, As, Hg, Sb, and Al) were calculated for the assessment of theoretical health risk. Satisfactory method performance parameters were found for each analyte. The results were compared with the maximum permissible limits set by regulatory agencies; 38 of 41 lip products (92.68%) and all eye shadows (n = 49) exceeded the established limits. The HI was found to be ≥ 1 in 82.76% of lip products for oral exposure, whereas HI was ≤ 1 for dermal exposure in all lip products (n = 41) and only one eye shadow sample was ≥ 1 (2.04%). Remarkable results were also detected for 19 elements in this study, which conducted a comprehensive inorganic profiling for the first time. Wide-range concentrations of Mg, Al, Ba, Mn, Cu, Zn, and Sr elements were remarkable. HI values were firstly brought out in this study, although Al, as a well-known toxic element, has not been listed in regulations yet. In conclusion, it is obviously seen that continuous monitoring of cosmetics is crucial not only for toxic elements but also for other essential or non-toxic elements to prevent consumers from long-term exposure.

Metal behavior and soil quality changes induced by the application of tailor-made combined biochar: An investigation at pore water scale

The remediation performance of biochar varies based on the biomass used for its production. Further innovation involves developing tailor-made biochar by combining different raw materials to compensate for the limitations of pure biochar. Therefore, tailor-made combined biochar produced from the co-pyrolysis of pig manure and invasive Japanese knotweed (P1J1), as well as biochars produced from these feedstocks separately, i.e., pure pig manure (PM) and pure Japanese knotweed (JK), were applied to Pb and As contaminated soil to evaluate the biochar-induced changes on soil properties, microbial activity, DOM, and metal and metalloids solubility at the soil pore water scale. Biochar application reduced soluble Pb, whereas enhanced the As mobility; the increased soil pH after biochar addition played a fundamental role in reducing the Pb solubility, as revealed by their significant negative correlation (r = -0.990, p < 0.01). In contrast, the release of dissolved P strongly influenced As mobilization (r = 0.949, p < 0.01), especially in P-rich PM and P1J1 treatments, while JK showed a marginal effect in mobilizing As. Soils treated with PM, P1J1, and JK mainly increased Gram-negative bacteria by 56 %, 52 %, and 50 %, respectively, compared to the control. Fluorescence excitation-emission matrix spectroscopy combined with parallel factor analysis identified three components in pore water DOM, C1 (long wavelength humic-like), C2 (short wavelength humic-like), and C3 (protein-like), which were dominant respectively in the P1J1, JK, and PM-added soil. A principal component analysis (PCA) confirmed that the PM and P1J1 had similar performance and were more associated with releasing P and Mg and specific DOM components (C1 and C3). Meanwhile, P1J1 supplemented soil OM/OC and K, similar to JK. The results of this study suggest that combined biochar P1J1 can comprehensively enhance soil quality, embodying the advantages of pure PM and JK biochar while overcoming their shortcomings.

A comprehensive approach to quantify the source identification and human health risk assessment of toxic elements in park dust

In this research, enrichment factor (EF) and pollution load index were utilized to explore the contamination characteristics of toxic elements (TEs) in park dust. The results exhibited that park dust in the study area was mainly moderately polluted, and the EF values of dust Cd, Zn, Pb, Cu and Sb were all > 1. The concentrations of Cr, Cu, Zn and Pb increased with the decrease of dust particle size. The investigation results of chemical speciation and bioavailability of TEs showed that Zn had the highest bioavailability. Three sources of TEs were determined by positive matrix factorization model, Pearson correlation analysis and geostatistical analysis, comprising factor 1 mixed sources of industrial and transportation activities (46.62%), factor 2 natural source (25.56%) and factor 3 mixed source of agricultural activities and the aging of park infrastructures (27.82%). Potential ecological risk (PER) and human health risk (HHR) models based on source apportionment were exploited to estimate PER and HHR of TEs from different sources. The mean PER value of TEs in the park dust was 114, indicating that ecological risk in the study area was relatively high. Factor 1 contributed the most to PER, and the pollution of Cd was the most serious. There were no significant carcinogenic and non-carcinogenic risks for children and adults in the study area. And factor 3 was the biggest source of non-carcinogenic risk, and As, Cr and Pb were the chief contributor to non-carcinogenic risk. The primary source of carcinogenic risk was factor 2, and Cr was the cardinal cancer risk element.

Considerations for environmental biogeochemistry and food security for aquaculture around Lake Victoria, Kenya

The impact of population expansion through economic growth and development has been identified as one of the key drivers of both water and sediment contamination from potentially harmful elements (PHEs). This presents a major hazard not only to aquatic ecosystems but local riparian communities and beyond who rely heavily on this natural resource for drinking water and fish-a valuable source of dietary micronutrients and protein. The present study measured biogeochemical concentration of PHEs in water, sediment and fish from locations pooled into four zones within Winam Gulf and Lake Victoria area of Kenya. Captured fish were used as a sentinel receptor of lake health to evaluate potential risks to fisheries and aquaculture food security. In water, concentrations of arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu) and lead (Pb) were observed above the United States Environmental Protection Agency (US EPA) maximum contamination level drinking water guidelines (MCL), with aluminium (Al) observed above the Aquatic Life Criteria in all four zones. Similarly, sediment concentrations in all four zones exceeded the US EPA Effects range low (ERL) threshold guidelines for Cu, nickel (Ni), zinc (Zn) and Pb, with Cu, Zn and Pb classed at moderate contamination levels using the contamination factor. Fish tissue concentrations from the four zones were calculated using recommended daily intakes (RDI) and for PHEs as provisional maximum tolerable intakes (PMTIs) and indicated most macro- and micronutrients were at or below 10% RDI from aquaculture and wild fish, with Se indicating a greater RDI (16-29%) in all the zones. Contributions of PHEs to PMTIs were below threshold guidelines for both aquaculture and wild fish with only Cd, Cr and Pb levels being above the PMTI thresholds. There is a need to assess the long-term effects of persistent anthropogenic PHE input into Winam Gulf and the wider Lake Victoria basin. Continued monitoring of PHEs using both historical and more recent data will enable future management policies to be implemented through improved mitigation strategies to reduce their impact on water quality, fish health and subsequent human health.

Foliar application of nanoceria attenuated cadmium stress in okra (Abelmoschus esculentus L.)

Foliar application of nanoparticles (NPs) as a means for ameliorating abiotic stress is increasingly employed in crop production. In this study, the potential of CeO₂-NPs as stress suppressants for cadmium (Cd)-stressed okra (Abelmoschus esculentus) plants was investigated, using two cycles of foliar application of CeO₂-NPs at 200, 400, and 600 mg/l. Compared to untreated stressed plants, Cd-stressed plants treated with CeO₂-NPs presented higher pigments (chlorophyll a and carotenoids). In contrast, foliar applications did not alter Cd root uptake and leaf bioaccumulation. Foliar CeO₂-NPs application modulated stress enzymes (APX, SOD, and GPx) in both roots and leaves of Cd-stressed plants, and led to decreases in Cd toxicity in plant's tissues. In addition, foliar application of CeO₂-NPs in Cd-stressed okra plants decreased fruit Cd contents, and improved fruit mineral elements and bioactive compounds. The infrared spectroscopic analysis of fruit tissues showed that foliar-applied CeO₂-NPs treatments did not induce chemical changes but induced conformational changes in fruit macromolecules. Additionally, CeO₂-NPs applications did not alter the eating quality indicator (Mg/K ratio) of okra fruits. Conclusively, the present study demonstrated that foliar application of CeO₂-NPs has the potential to ameliorate Cd toxicity in tissues and improve fruits of okra plants.

Elemental Analysis of Laryngeal Cancer Patients in Comparison with Controls Using Scalp Hair as an Analytical Tool

Laryngeal cancer, a rare form of head and neck cancer, is more common in men, and various factors play important roles in its etiology. In the current study, trace elemental contents in the scalp hair of laryngeal cancer patients and healthy subjects were evaluated. Selected essential and toxic elements were measured using flame atomic absorption spectrophotometry after the hair samples were digested with HNO₃-HClO₄. The mean/median levels of Pb in the scalp hair of patients were significantly higher than the healthy donors, but Sr, Zn, and Co exhibited comparatively lower levels in the laryngeal cancer patients. In comparison to healthy donors, the correlation pattern among the elements in the hair of the patients exhibited diverse mutual relationships. The multivariate apportionment of the elemental levels in the scalp hair of both donor groups was significantly divergent. The average elemental levels varied significantly among the cancer types (glottic, supraglottic, transglottic, and subglottic) as well as the cancer stages (I, II, III, IV). The average levels of the elements also exhibited considerable variations depending on the donors' habitat, gender, food, and smoking habits. Overall, the study revealed significantly divergent disparities among the elemental contents in the scalp hair of the laryngeal cancer patients in comparison with counterpart controls.

Receptor model-oriented sources and risks evaluation of metals in sediments of an industrial affected riverine system in Bangladesh

Toxic metals in river sediments may represent significant ecological concerns, although there has been limited research on the source-oriented ecological hazards of metals in sediments. Surface sediments from an industrial affected Rupsa River were utilized in this study to conduct a complete investigation of toxic metals with source-specific ecological risk assessment. The findings indicated that the average concentration of Ni, Cr, Cd, Zn, As, Cu, Mn and Pb were 50.60 ± 10.97, 53.41 ± 7.76, 3.25 ± 1.73, 147.76 ± 36.78, 6.41 ± 1.85, 59.78 ± 17.77, 832.43 ± 71.56 and 25.64 ± 7.98 mg/kg, respectively and Cd, Ni, Cu, Pb and Zn concentration were higher than average shale value. Based on sediment quality guidelines, the mean effective range median (ERM) quotient (1.29) and Mean probable effect level (PEL) quotient (2.18) showed medium-high contamination in sediment. Ecological indexes like toxic risk index (20.73), Nemerow integrated risk index (427.59) and potential ecological risk index (610.66) posed very high sediment pollution. The absolute principle component score-multiple linear regression (APCS-MLR) and positive matrix factorization (PMF) model indicated that Zn (64.21%), Cd (51.58%), Cu (67.32%) and Ni (58.49%) in APCS-MLR model whereas Zn (49.5%), Cd (52.7%), Cu (57.4%) and Ni (44.6%) in PMF model were derived from traffic emission, agricultural activities, industrial source and mixed sources. PMF model-based Nemerow integrated risk index (NIRI) reported that industrial emission posed considerable and high risks for 87.27% and 12.72% of sediment samples. This work will provide a model-based guidelines for identifying and assessing metal sources which would be suitable for mitigating future pollution hazards in Riverine sediments in Bangladesh.

Probabilistic health risk assessment for residents exposed to potentially toxic elements near typical mining areas in China

Public health problems caused by toxic elements in mining areas have always been an important topic worldwide. However, existing studies have focused on single exposure routes and common toxic elements, which might underestimate the risks faced by residents. In this study, three typical mining areas in central China were selected to assess the health risks of 14 potentially toxic elements through five exposure routes using Monte Carlo simulations. The results indicated that the 95th percentile non-carcinogenic risk values to humans via rice and vegetable ingestion ranged from 9.8 to 26.0 and 6.2 to 19.0. The corresponding carcinogenic risks ranged from 1.4E-2 to 6.3E-2 and from 2.9E-3 to 2.3E-2, respectively. Therefore, residents face serious health risks. Multi-element analysis showed that cadmium (Cd), boron (B), and arsenic (As) were the main contributors to rice non-carcinogenicity, whereas Cd and nickel (Ni) were the main elements of rice carcinogenicity. B and lead (Pb) played an essential role in the non-carcinogenesis of vegetables, and B, Ni, and Cd played an essential role in carcinogenesis. Accidental ingestion is the main route of soil exposure. In these three areas, the probability of non-carcinogenic risk faced by adults was 40%, 0%, and 1%, respectively, while the probabilities for children were 100%, 62%, and 83%, respectively. Regarding carcinogenicity, the risk for both adults and children was up to 100%. This study emphasizes the overall health risks in polluted areas via multi-route and multi-element analysis. This conclusion is helpful to comprehensively assess the potential health risks faced by residents in mining areas and provide baseline data support and a scientific basis for formulating reasonable risk control measures.

Updated interim reference levels for dietary lead to support FDA's Closer to Zero action plan

The Centers for Disease Control and Prevention (CDC) utilizes a blood lead reference value (BLRV) to identify children with elevated blood lead levels (BLLs). At or above the BLRV, the CDC recommends actions be taken to reduce children's BLLs. In 2021, the CDC updated its BLRV to 3.5 μg/dL. To align with the CDC's updated BLRV, the FDA is updating its interim reference levels (IRLs) for lead from food to 2.2 μg/day for children and 8.8 μg/day for females of childbearing age. The updated FDA IRLs for lead will serve as a benchmark to evaluate whether lead exposure from food is a potential concern. The children's BLL associated with the updated IRL is less than those predicted by other agencies to result in 1 intelligence quotient point loss. Dietary lead exposure estimates for children in the U.S. suggest exposures greater than the mean may exceed the updated FDA IRL for children, indicating a need for additional efforts to reduce lead in foods consumed by young children. The US FDA is addressing this need by implementing its Closer to Zero action plan to reduce babies' and children's dietary exposure to toxic elements (e.g., lead, cadmium, arsenic, mercury) over time.

Brevundimonas diminuta isolated from mines polluted soil immobilized cadmium (Cd2+) and zinc (Zn2+) through calcium carbonate precipitation: Microscopic and spectroscopic investigations

The toxic metal(loid)s TMs resistant bacterium Brevundimonas diminuta was isolated for the first time from mines polluted soil in Fengxian, China, and assessed for its potential for Cd and Zn precipitation in Cd and Zn co-contaminated aqueous solution at various Cd and Zn levels (20, 40, 80, 160, and 200 mg L^-1), pH values (5, 6, 7, 8, and 9), and temperatures (20, 25, 30, and 35 °C). B. diminuta showed a high resistance to both Cd and Zn and was able to precipitate up to 99.2 and 99.7% of dissolved Cd and Zn respectively, at a pH of 7 and temperature of 30 °C. B. diminuta reduced the dissolved concentrations of Cd and Zn below the threshold levels in water. The 3D-EEM analysis revealed the presence of extracellular polymeric substances (EPS) such as tryptophan indicating bacterial growth under Cd/Zn stress. FTIR showed polysaccharides, CO₃^2-, CaCO₃, PO₄^3-, and proteins, which may enhance bacterial growth and metal precipitation. SEM-EDS confirmed the leaf-like and granular shape of the biological precipitation and reduction in the percent weight of TMs, which promoted the adhesion/adsorption of Cd²⁺, Zn²⁺, and Ca²⁺. Moreover, XRD analysis confirmed the precipitation of Cd, Zn, and Ca in the form of CdCO₃/Cd₃(PO₄)₂, ZnCO₃/ZnHPO₄/Zn₂(OH)PO₄/Zn₃(PO₄)₂, and CaCO₃/Ca₅(PO₃)₄OH, respectively. These findings indicate that Brevundimonas diminuta can be used for the bioremediation of TMs-contaminated aquatic environments.

Level, source, and risk assessment of toxic elements in traditional agricultural soils and coping strategies

The level, source, and risk of toxic elements in traditional agricultural soils are particularly crucial for the sustainable development of agriculture. An important agricultural production base was selected, a total of 251 topsoil samples were collected, eight toxic elements (As, Cd, Cr, Cu, Hg, Ni, Pb, Zn) in soil were analyzed, and environmental and health risk assessments were conducted. Results showed that all concentrations of eight elements in soil samples were lower than the risk screening values with negligible pollution risk. Approximately 83.8% of Hg in soil was originated from atmospheric deposition related to industrial emissions, 53.2% of Cd was derived from direct industrial activities, and the other elements came from soil parent materials or agricultural activities. Accumulation risk of As in agricultural products, potential ecological risk from Cd, and As's ingestion risk and Cr's dermal contact risk should be paid more attention. More stricter monitoring and coping countermeasures and strategies should be established to ensure the sustainable development of agriculture.

Concentration of Potentially Harmful Elements (PHEs) in Trout Fillet (Rainbow and Brown) Fish: a Global Systematic Review and Meta-analysis and Health Risk Assessment

In this work, articles regarding the concentration on potentially harmful elements (PHEs) in fillet trout (rainbow and brown) fishes were retrieved from Cochrane, Scopus, and PubMed databases between 1 January 1983 and 30 April 2020. The pooled concentration of PHEs in fillet trout fishes was meta-analyzed using a random-effect model (REM) and following the non-carcinogenic and carcinogenic risks was calculated using the Monte Carlo simulation (MCS) method. The meta-analysis of 42 articles (43 data report) revealed that a sort of PHEs in fillet trout was 19,996.64 μg/kg ww for Fe; 1834.75 μg/kg ww for Co; 772.21 μg/kg ww for Cu; 335.78 μg/kg ww for Ni; 290.46 μg/kg ww for Se; 226.20for Cr; 178.11 μg/kg ww for Pb; 77.40 μg/kg ww for Hg; 19.40 μg/kg ww for Cd; and 3.66 μg/kg ww for inorganic As. The non-carcinogenic risk assessment indicated that the lowest and highest hazard index (HI) in the adults was Pakistan (0.0012) and Turkey (0.2388), respectively, and in children was Pakistan (0.0057) and Turkey (1.114), respectively. The non-carcinogenic risk was acceptable for adult consumers in all countries (HI > 1 value) but non-carcinogenic risk for children was not acceptable in Turkey. The sort of countries based on carcinogenic risk in the adults due to inorganic As was China (1.44E-06) > Iran (9.14E-08) > Turkey (4.45E-08) > Portugal (9.04E-10). The carcinogenic risk was threshold for adult consumers in China (CR < 10^-6). Consumption of fillet trout (rainbow and brown) content of PHEs in many countries cannot endanger the health of consumers.

Brazilian Genetic Diversity for Desirable and Undesirable Elements in the Wheat Grain

Micronutrient deficiency affects billions of people, especially in countries where the diet is low in diversity with inadequate consumption of fruits, vegetables, and animal-source foods, and higher consumption of staple food, i.e., cereals, that have low concentrations of micronutrients. Genetic biofortification is a strategy to mitigate this problem and ensure nutritional security. Wheat is a target of genetic biofortification since it contributes significantly to the caloric requirement. The biofortification process involves a screening related to the presence of genetic variability for grain mineral content. Also, the accumulation of toxic elements must be considered to ensure food safety, because if ingested above the allowed concentrations, it represents health risks. In this sense, this study aimed to quantify the micronutrients iron, zinc, copper, selenium, and manganese and toxic elements arsenic and cadmium in a Brazilian wheat panel grown in Southern Brazil. The presence of genetic variability for the accumulation of micronutrients in the grain was detected; however, we observed that only the copper and manganese accumulation meet the human daily requirements. Iron, zinc, and selenium were detected in insufficient concentration to meet the daily demand. Arsenic and cadmium accumulation were not detected in wheat grain. The wheat genotypes grown in Brazil displayed a similar profile to that found in other countries which may be due to common high-yield breeding goals and the narrowing of the genetic variability, observed worldwide. Thus, the wheat genetic biofortification success in Brazil depends on the introduction of foreign genotypes, landraces, and wild relatives.

Pollution status and health risk caused by heavy elements in the flooded soil and vegetables from typical agricultural region in Vojvodina Province, Serbia

The investigation conducted in the Vojvodina Province, as a typical European and one of the biggest agricultural regions in the Balkans, offers the research methodology that could be used for any non/flooded agricultural region. The flood impact on heavy elements (HE) content in the flooded arable soil (n = 16) in relation to the control soil (n = 16) was examined, as well as their accumulation in the most often cultivated vegetables (n = 96) in the studied area. Results revealed that the flood did not significantly change the pseudo total HEs concentration in the soil as well as their amounts accumulated in different soil fractions. In both soils, only the average content of Ni exceeded the maximum permissible values set by Serbian soil quality standard which is in line with the Dutch standard. In comparison with the background values, notable enrichment is found for most of analyzed elements in both soils. Soil pollution status was assessed through several indices indicating that contamination range was in the domain from a moderate to a highly polluted. The principal component analysis demonstrated that soil contamination was probably originated from agricultural/anthropogenic activities (Cd, Cu, As, Pb), apart from Ni, Cr, and Co which came from natural weathering of the parent material. Carcinogenic and non-carcinogenic risks of selected HEs for Serbian population in the investigated region were below the threshold values. The average levels of Pb in investigated potato and carrot samples were higher than the maximum allowable concentrations established by EU/Serbian regulation. The total hazard quotients (THQ) of HEs through intake of analyzed vegetables were below the safe threshold (˂ 1), suggesting the absence of adverse health effects.

Direct determination of Al and Pb in waste printed circuit boards (PCB) by laser-induced breakdown spectroscopy (LIBS): Evaluation of calibration strategies and economic - environmental questions

Matrix-matching calibration (MMC), two-point calibration transfer (TP CT), one-point and multi-line calibration (OP MLC), single-sample calibration (SSC) and calibration free (CF) were evaluated in order to overcome matrix effects in laser-induced breakdown spectroscopy (LIBS). These calibration strategies were evaluated for direct determination of Al and Pb in waste printed circuit boards (PCB) using direct solids analysis by LIBS. Each strategy has limitations and advantages of its implementation, for the correction of matrix effects, so that it allows elementary determination with adequate accuracy. The MMC and CF proved to be excellent calibration strategies for the determination of strategic (Al) and toxic (Pb) elements by LIBS, with good recoveries (ranging from 80-120%) and low relative standard deviation (RSD%) values. A detailed discussion of the advantages and limitations of each of these five calibration strategies evaluated for LIBS is presented in this study. Lead concentrations in waste PCB samples are 5-12 times higher than established by Directive 2011/65/EU, and the samples analyzed contain between 3 and 55 g kg^-1 Al, being an interesting economic and recycling source for this metal.

Effect of arsenic stress on 5-methylcytosine, photosynthetic parameters and nutrient content in arsenic hyperaccumulator Pteris cretica (L.) var. Albo-lineata

BACKGROUND

Arsenic toxicity induces a range of metabolic responses in plants, including DNA methylation. The focus of this paper was on the relationship between As-induced stress and plant senescence in the hyperaccumulator Pteris cretica var. Albo-lineata (Pc-Al). We assume difference in physiological parameters and level of DNA methylation in young and old fronds as symptoms of As toxicity.

RESULTS

The As accumulation of Pc-Al fronds, grown in pots of haplic chernozem contaminated with 100 mg As kg- 1 for 122 days, decreased with age. Content of As was higher in young than old fronds for variants with 100 mg As kg- 1 (2800 and 2000 mg As kg- 1 dry matter, respectively). The highest As content was determined in old fronds of Pc-Al grown in pots with 250 mg As kg- 1. The increase with age was confirmed for determined nutrients - Cu, Mg, Mn, S and Zn. A significant elevation of all analysed nutrients was showed in old fronds. Arsenic accumulation affected DNA methylation status in fronds, but content of 5-methylcytosine (5mC) decreased only in old fronds of Pc-Al (from 25 to 12%). Determined photosynthetic processes showed a decrease of fluorescence, photosynthetic rate and chlorophylls of As treatments in young and old fronds. Water potential was decreased by As in both fronds. Thinning of the sclerenchymatous inner cortex and a reduction in average tracheid metaxylem in the vascular cylinder was showed in roots of As treatment. Irrespective to fronds age, physiological parameters positively correlated with a 5mC while negatively with direct As toxicity. Opposite results were found for contents of Cu, Mg, Mn, S and Zn.

CONCLUSIONS

The results of this paper point to changes in the metabolism of the hyperaccumulator plant Pc-Al, upon low and high exposure to As contamination. The significant impact of As on DNA methylation was found in old fronds. Irrespective to fronds age, significant correlations were confirmed for 5mC and As toxicity. Our analysis of the very low water potential values and lignification of cell walls in roots showed that transports of assimilated metabolites and water between roots and fronds were reduced. As was showed by our results, epigenetic changes could affect studied parameters of the As hyperaccumulator plant Pc-Al, especially in old fronds.

Mineralogical phase separation and leaching characteristics of typical toxic elements in Chinese lignite fly ash

To investigate the distribution characteristics of typical toxic elements in different mineralogical phases of fly ash is of significance when fly ash is comprehensively utilized. In this study, lignite fly ash can be preliminarily separated into three mineralogical phases: unburned lignite, iron microbeads and aluminate-silicate microbeads by two methods namely screening and dry magnetic separation. Then, the aluminate-silicate microbeads were subjected to two-step leaching. The first step was to investigate whether toxic elements migrated easily in the environment by column leaching test. In the second step, the aluminate-silicate microbeads were stripped from the surface of the particles to the internal by the acid-base combined leaching method, then the structural characteristics of the product and the trend of toxic elements content were explored. The results showed that there were few toxic elements in unburned lignite and the toxic elements Cr, Ni, Mo and Cd had a relatively high proportion in the iron microbeads. Column leaching results showed that the toxic elements V, Cr, Mn, Co, Cu, Hg and Pb had higher leaching rates, which proved that these elements were significantly enriched on the surface of the particles and easily migrated in the environment. Cr, Mo, Cd and W were highly enriched in the quartz-mullite mixture. Mn, Co, Ni, Cu, Zn and As were highly enriched in the amorphous component. The toxic elements exhibited different leaching rules during the acid-base combined leaching process revealing the complex embedded relationship with constant elements.

A comparative study of elemental pollution and health risk assessment in urban dust of different land-uses in Tehran's urban area

Pollution levels of potentially toxic metals (PTMs) were studied performing enrichment factor, geo-accumulation index and ecological risk index. The most enriched elements which categorize as very high and extremely high enriched in different land-uses were in order of: commercial Cu (73.79)>Hg (66.55)>Pb (55.73)>Zn (46.15)>Cd (37.31); residential Pb (48.35)>Zn (34.79)>Cu (27.69)>Hg (22.96)>Cd (22.61) and industrial Zn (55.43)>Pb (51.52)>Cu (40.20)>Cd (26.29). In green lands sampling points, there weren't any elements with enrichment factor more than twenty. Based on the result of geo-accumulation index, commercial land-use appeared to be highly polluted with Cu, Pb and Zn. Residential land-use were highly polluted just in case of lead and industrial land-use were categorized as highly polluted in case of Zn, Pb and Cu. Hakanson's ecological risk index classified all of the land-uses except for green lands as very high ecological risk category. Factor analysis revealed that Cr, Mn, Ni, Fe and to a lesser extent Pb, Zn and As are from similar anthropogenic sources. Carcinogenic risk of Cr, Pb, As, Ni and Cd were found to be negligible for all land-uses for adult and children except for chromium in commercial land-use which exceed the safe level and need more attention in the future.

Biochar-induced metal immobilization and soil biogeochemical process: An integrated mechanistic approach

The nature of biochar-derived dissolved organic matter (DOM) has a crucial role in the interactions between biochar and metal immobilization, carbon dynamics, and microbial communities in soil. This study utilized excitation-emission matrix coupled with parallel factor analysis (EEM-PARAFAC) modeling to provide mechanistic evidence of biochar-induced influences on main soil biogeochemical processes. Three biochars produced from rice straw, wood, and grass residues were added to sandy and sandy loam soils and incubated for 473 d. Microbial and terrestrial humic-like fluorescent components were identified in the soils after incubation. The sandy loam soil exhibited a higher DOM with microbial sources than did the sandy soil. All biochars reduced Pb bioavailability, whereas the rice straw biochar enhanced the As bioavailability in the sandy loam soil. The biochar-derived aliphatic-DOM positively correlated with As bioavailability (r = 0.82) in the sandy loam soil and enhanced the cumulative CO₂-C (r = 0.59) in the sandy soil. The promoted cumulative CO₂-C in the sandy soil with all biochars correlated with the enhanced microbial communities, in particular, gram-positive (r = 0.59) and gram-negative (r = 0.59) bacteria. Our results suggest that the integration of EEM-PARAFAC with spectroscopic indices could be useful for a comprehensive interpretation of the soil quality changes in response to the application of biochar.

Evaluation of human health risk assessment of potential toxic metals in commonly consumed crayfish (Palaemon hastatus) in Nigeria

Concentrations of potentially toxic metals were determined in crayfish (Palaemon hastatus) commonly consumed in Nigeria using Atomic Absorption Spectrophotometry. Results revealed that Fe had the highest mean value of 18.88 ± 0.10 μg/g, while Pb had the least (0.91 ± 0.01 μg/g). Cluster analysis showed close inter-element relationships between the metals, indicating similar chemical properties and/or genetic origin. Correlation matrix indicated positive and significant correlations between Cr/Cd, Fe/Cd, Fe/Cr, Pb/Cd, Pb/Fe and Cu/Zn, establishing chemical affinity. Estimated daily intake, target hazard quotient and cancer risk showed that there was no health risk associated with the consumption of the crayfish. Relative risk showed that potential health risk could be attributed only to Cd level. The study concluded that consumption of the crayfish may not pose health risk to human health at the levels of the analysed metals, but should be consumed moderately to prevent bioaccumulation of the metals most importantly Cd.

Examining the link between dose-dependent dietary iron intake and Alzheimer's disease through oxidative stress in the rat cortex

BACKGROUND

Neurodegenerative diseases such as Alzheimer's and Parkinson's disease are characterized by the progressive deterioration of the structure and function of the nervous system. A number of environmental risk factors including potentially toxic elements such as iron, lead to negative effects on many metabolic reactions as well as neuroprotection. The aim of this study is to reveal whether long-term iron overload is one of the underlying factors in the pathogenesis of Alzheimer's disease (AD).

METHODS

15 young-adult male rats were randomly divided into 5 groups treated with iron through drinking water for 4 months. Following feeding, the iron content, reduced glutathione (GSH), and hydrogen peroxide (H₂O₂) levels of cortex tissues were measured. Specific enzyme activities were determined spectrophotometrically. mRNA expression profiles were measured using real-time PCR (qPCR).

RESULTS

Iron levels were elevated in case of non-toxic (0.87 and 3 μg/mL) iron administration. However, no changes were observed in toxic (30 and 300 μg/mL) iron administration. GSH and H₂O₂ levels altered with long-term iron overload. Glutathione peroxidase (GPx) enzyme activities significantly increased in all groups, while glutathione S-transferase (GST) activity increased only in case of 0.87 and 30 μg/mL iron administration. Expression levels of neuroprotective and AD-related genes were altered by 3 μg/mL iron overload in a dose-dependent manner. The expression and activity of acetylcholinesterase (AChE) were elevated at 3 μg/mL iron concentration.

CONCLUSION

The findings of the present study allow us to conclude that long-term dietary iron intake, especially at a dose of 3 μg/mL demonstrates negative effects on the rat cortex by provoking antioxidant metabolism and AD pathology in a dose-dependently.

Risk-based prediction of metal toxicity in sediment and impact on human health due to consumption of seafood (Saccostrea cucullata) found in two highly industrialised coastal estuarine regions of Eastern India: a food safety issue

Estuarine ecosystems of the Bay of Bengal, India, are considered as the most productive environment, which have been persistently threatened by substantial anthropogenic activity. This study aims to investigate the metal contamination in the sediment of two estuaries and possible biomagnifications in the indigenous edible oyster Saccostrea cucullata and related health hazards due to its consumption. The accumulative ecological risks indicated that the sediment is moderate to strongly contaminated with cadmium and lead. The sediment pollution index and pollution load index suggested that the sediment possesses a little ecological stress on the exposed flora and fauna. The statistical interpretation highlights the most metals which have a similar source of origin and are bound to the finer fractions of the sediment, except nickel. Bioaccumulation of sediment-associated Cu and Zn in oyster reflects their potential biomagnifications through aquatic food chain. HPI range was below the critical limit of safe human consumption. The non-carcinogenic (THQ) and carcinogenic (CR) health hazards were estimated from the PTDI provided by USEPA. Except Cr, Hg and Zn, the THQ of all other metals was > 1 suggesting detrimental non-carcinogenic health effects on humans. The TCR of Cr and Cd above safety limit indicates the exposed population might be under severe carcinogenic threat due to those metals.

A prophylactic multi-strain probiotic treatment to reduce the absorption of toxic elements: In-vitro study and biomonitoring of breast milk and infant stools

Potential exposure to toxic elements initially occurs during gestation and after birth via breast milk, which is the principal source of nutrients for infants during the first months of life. In this study, we evaluated whether maternal oral supplementation with a multi-strain probiotic product can protect infants from exposure to arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb) via breast milk. In-vitro studies of the bacterial strains present in this probiotic product showed a high bacterial tolerance for As, Cd, Hg, and Pb, and good binding capacity for Cd, Hg, and Pb (72%, 81%, and 64%, respectively) within 1 h of contact. We evaluated concentrations (5 mg L^-1 for Cd and Pb, and 2 mg L^-1 for Hg) that largely exceeded the provisional tolerable weekly intake of these toxic elements via food or water applicable for human consumption. Changes in the levels of these elements in breast milk and newborn stools were evaluated in the control (orally supplemented with placebo) and experimental (orally supplemented with probiotic) groups at birth (t0), 15 days (t15), and 30 days (t30) after delivery. Elemental analysis of breast milk did not show significant differences between the control and experimental groups at different stages of lactation; however, stool samples obtained from newborns of mothers supplemented with the probiotic product showed that Cd levels were significantly reduced (by 26%) at t15 compared with the levels of the controls. Our data did not show an association between concentration of toxic elements in breast milk and that in newborn stools. Indeed, the concentration of Cd, Hg, and Pb in breast milk decreased during the lactation period, whereas the levels of these elements in newborn stools were stable over time. Although our in-vitro data indicate that the consortium of these probiotic strains can absorb toxic compounds, this study was limited by its small sample size and potential uncontrolled confounding effects, such as maternal diet and lifestyle. Therefore, we could not confirm whether prophylactic use of this probiotic product can reduce the absorption of toxic elements. The risk assessment in the studied population evidenced a margin of exposure (MOE) of 1, or between 1 and 10 for Pb, and lower than 50 for As. This poses a potential risk for breastfed infants, indicating that interventions aimed to avoid breastfeeding-related health risks remain a major challenge in public health.

Prevalence and Factors Associated with High Levels of Aluminum, Arsenic, Cadmium, Lead, and Mercury in Hair Samples of Well-Nourished Thai Children in Bangkok and Perimeters

Toxic element exposure increases risk of neurodevelopmental disorders. However, hair element profiles of well-nourished urban resident children were largely unknown. We identified prevalence and the contributing factors of high hair aluminum (Al), arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg) levels in 111 Thai children (aged 3-7 years old). Most participants were well-nourished with high socioeconomic status. Since ROC curve of hair element data showed inadequate sensitivity for cutoff set-up, US reference hair levels were used to categorize high and low level groups. Nevertheless, compared to the current reference at 5 μg/dL, blood lead cutoff at 2.15 μg/dL provided more consistent results with that of hair lead levels. High As and Pb levels were the first and second most prevalent element, while Al was the element found in highest amount in hair. High hair Al (12% prevalence) levels were associated with being male regardless of age or nutritional status. High hair As levels were associated with living in Bangkok (OR = 6.57) regardless of school type. High hair Pb levels were associated with being under 5 years old and living in Bangkok (OR = 3.06). However, no associations were found between blood Pb, hair Cd, Hg, and tested factors. These findings suggested that under 5-year-old boys living in capital city like Bangkok may be at risk of exposure to multiple toxic elements. Future studies in these children are warranted to identify their exposure sources and proper risk management strategies.

Post-depositional changes in elemental leaching from recovered soils separated from disaster waste and tsunami deposits generated by the Great East Japan Earthquake and tsunami

The Great East Japan Earthquake and subsequent tsunami in 2011 generated massive amounts of disaster waste and tsunami deposits, one-third of which comprised soil and sediment, which are expected to be re-used; however, there has been no previous experience or knowledge of recovered soil. In this study, up-flow column leaching tests were conducted to investigate the elemental leaching behavior in this soil and sediment following its separation and treatment (hereafter termed "recovered soil") to assess whether it can be safely re-used without posing any environmental risk. The pH of the leaching water was slightly alkaline throughout the test period, regardless of the source of the recovered soil. Concentrations of calcium and sulfate ions in the leaching water varied in a similar way to the electrical conductivity (EC), with a stable state being observed initially followed by a rapid decrease until typical concentrations were reached, whereas sodium and chloride ions derived from seawater made a relatively small contribution to the EC. In terms of toxic elements, zinc and copper concentrations decreased as the volume of leaching water increased, whereas lead, fluoride, and arsenic concentrations increased as the concentration of calcium and sulfate ions decreased, indicating that the dissolution of large quantities of compounds such as calcium sulfate controlled the toxic element behavior in the recovered soils. Consequently, there is a need for continuous and careful monitoring of areas where recovered soil is re-used or treatment of the recovered soil prior to its re-use.

Volatilization of toxic elements from coal samples of Thar coal field, after burning at different temperature and their mobility from ash: Risk assessment

In present study, the volatilization of arsenic (As), cadmium (Cd), mercury (Hg) and lead (Pb) by the burning of coal samples in the electric furnace was evaluated. The coal samples were obtained from different blocks of newly developed Thar coal field, Pakistan. The replicate coal samples were heated/burned in an electric furnace at laboratory scale for three temperature intervals (200, 400 and 900 °C). The ash obtained after each temperature intervals were analyzed for selected toxic elements. The resulted data indicated that the total contents of As, Cd, and Pb in coal samples of block X and XI were found in the range of 16.8-18.5, 4.21-4.72, and 14.2-18.8 mg/kg, respectively. Whereas, 67.8-79.7%, 34.3-36.8% and 9.89-10.8% of As, Cd, and Pb, respectively, were volatized out after combustion of coal samples at 900 °C. The total contents of Hg in selected coal samples of block X and XI were observed in the range of 0.985-1.46 and 0.992-1.41 mg/kg, respectively. The contents of Hg volatilized out via burning in a furnace at 200 °C and 400 °C, were observed in the range of 32.0-36.5% and >91.0% of its total contents, respectively, whereas at 900 °C, it was not detected in ash. The partitioning and mobility of studied toxic elements in residue termed as (laboratory made ash) obtained after burning at 900 °C, was carried out by three-step sequential extraction scheme. The resulted data of present study will give a better knowledge about the quality of coal and its burning product, which may help to take measure to reduce the adverse effects on the environment in future.

Impact of secondary generated minerals on toxic element immobilization for air pollution control fly ash of a municipal solid waste incinerator

Impacts of secondary generated minerals on mineralogical and physical immobilization of toxic elements were investigated for chelate-treated air pollution control (APC) fly ash of a municipal solid waste incinerator. Scanning electron microscope (SEM) observation showed that ettringite was generated after the moistening treatment with/without chelate. Although ettringite can incorporate toxic elements into its structure, elemental analysis by energy dispersive X-ray could not find concentrated points of toxic elements in ettringite structure. This implies that mineralogical immobilization of toxic element by the encapsulation to ettringite structure seems to be limited. Physical immobilization was also investigated by SEM observation of the same APC fly ash particles before and after the moistening treatment. The transfer of soluble elements was inhibited only when insoluble minerals such as gypsum were generated and covered the surface of fly ash particles. Neoformed insoluble minerals prevented soluble elements from leaching and transfer. However, such physical immobilization seems to be limited because insoluble mineral formation with surface coverage was monitored only one time of more than 20 observations. Although uncertainty owing to limited samples with limited observations should be considered, this study concludes that mineralogical and physical immobilization of toxic elements by secondary minerals is limited although secondary minerals are always generated on the surface of APC fly ash particles during chelate treatment.

Assessment of trace elements in terminal tap water of Hunan Province, South China, and the potential health risks

A total of 116 terminal tap water (TTW) samples from Xiangjiang, Zijiang, Yuanjiang, and Lishui river basins of Hunan province were collected and concentrations of As, Cd, Cr, Pb, Mn, Zn, Fe, Al, and Cu were determined using inductively coupled plasma mass spectrometry. The results showed that 10% of the water samples exceeded the limit level of Cd established by World Health Organization (WHO) of 0.003 mg L^-1. Three percent of the samples had Fe level and 1% had As level above the WHO limits of 0.3 and 0.01 mg L^-1, respectively. Multivariate statistic approach (cluster analysis and principal component analysis) results revealed that anthropogenic activities and pipeline corrosion were major sources of TTW contamination in Hunan province. The individual and total hazard quotient values estimated by deterministic and probabilistic approaches were both less than 1. However, the mean cancer risk values of Cd were 2.2 × 10^-4 and 1.4 × 10^-4 for Xiangjiang and Yuanjiang river basin, respectively, both greater than 10^-4. The 95th percentile value of cancer risk for Cr was slightly greater than 10^-4 in Xiangjiang river basins. Long-term exposure to Cd and Cr through tap water consumption poses moderate carcinogenic health risks to the local residents.

Status, source identification, and health risks of potentially toxic element concentrations in road dust in a medium-sized city in a developing country

This study aims to determine the status of potentially toxic element concentrations of road dust in a medium-sized city (Rawang, Malaysia). This study adopts source identification via enrichment factor, Pearson correlation analysis, and Fourier spectral analysis to identify sources of potentially toxic element concentrations in road dust in Rawang City, Malaysia. Health risk assessment was conducted to determine potential health risks (carcinogenic and non-carcinogenic risks) among adults and children via multiple pathways (i.e., ingestion, dermal contact, and inhalation). Mean of potentially toxic element concentrations were found in the order of Pb > Zn > Cr(IV) > Cu > Ni > Cd > As > Co. Source identification revealed that Cu, Cd, Pb, Zn, Ni, and Cr(IV) are associated with anthropogenic sources in industrial and highly populated areas in northern and southern Rawang, cement factories in southern Rawang, as well as the rapid development and population growth in northwestern Rawang, which have resulted in high traffic congestion. Cobalt, Fe, and As are related to geological background and lithologies in Rawang. Pathway orders for both carcinogenic and non-carcinogenic risks are ingestion, dermal contact, and inhalation, involving adults and children. Non-carcinogenic health risks in adults were attributed to Cr(IV), Pb, and Cd, whereas Cu, Cd, Cr(IV), Pb, and Zn were found to have non-carcinogenic health risks for children. Cd, Cr(IV), Pb, and As may induce carcinogenic risks in adults and children, and the total lifetime cancer risk values exceeded incremental lifetime.

Occurrence and mobility of toxic elements in coals from endemic fluorosis areas in the Three Gorges Region, SW China

Fluorine (F) is a topic of great interest in coal-combustion related endemic fluorosis areas. However, little extent research exists regarding the environmental geochemistry of toxic elements that are enriched in coals and coal wastes in traditional endemic fluorosis areas, particularly focusing on their occurrences and mobilities during the weathering-leaching processes of coals and coal wastes in the surface environment. This paper addressed the issue of toxic elements in coals and coal wastes in the Three Gorges Region, Southwest (SW) China, where endemic fluorosis has historically prevailed, and investigated the distribution, occurrence, mobility features, and associated potential health risks. For this purpose, a modified experiment combined with long-term humidity cell test and column leaching trial was applied to elucidate the mobility of toxic elements in coals and coal wastes. In addition, sequential chemical extraction (SCE) was used to ascertain the modes of occurrence of toxic elements. The results demonstrated that the contents of toxic elements in the study area followed the order: stone coals > gangues > coal balls > coals. Furthermore, modes of occurrence of toxic elements were obviously different in coals and coal wastes. For example, cadmium (Cd) was mainly associated with monosulfide fraction in coals, molybdenum (Mo) and arsenic (As) were mainly associated with carbonate and silicate in coal gangues and stone coals, chromium (Cr) mainly existed in silicate and insoluble matter in coal gangues and coal balls, thallium (Tl) mainly occurred in organic matter in stone coals and sulfide in coals, and the occurrence of antimony (Sb) varied with different kinds of samples. Moreover, a large amount of toxic elements released to the leachates during the weathering and leaching process, which might pollute the environment and threaten human health. Based on the geo-accumulation index (I_geo), single factor index (P_i) and Nemerow index (P_N), soils _in the study area were mainly polluted by Cd, which constituted a potential risk to locally planted crops.

Assessment of particulate emissions from a sinter plant in steelmaking works in China

In this paper, five particulate emission points from a sinter plant in China, including anthracite crusher, raw material blender, sinter strand, screener, and circular cooler, were selected for particle sampling. The particle size distribution, the toxic element content (As, Cd, Co, Cr, Cu, Ni, Pb, Ti, and Zn), and the morphology of the samples were determined by the gravimetric method, the ICP-OES, and the SEM-EDS, respectively. In addition, the gray relational analysis method was used to evaluate the rank of the particulate emission points in the sinter plant. The results show that the emission factor of PM_TSP, PM₁₀, and PM_2.5 of the whole sintering process is 0.121, 0.075, and 0.039 kg/t-sinter, respectively. Furthermore, the total toxic element emission factor is 5282.49 mg/t-sinter. The sinter strand is the most important emitter and contributes 43.8% of PM_TSP, 53.3% of PM₁₀, 56.4% of PM_2.5, and 81.1% of total toxic element in the sinter plant. Nevertheless, particles emitted from the post-sintering process are non-negligible and contribute 48.8% of PM_TSP, 41.3% of PM₁₀, 38.5% of PM_2.5, and 15.5% of total toxic element in the sinter plant.

Determination of essential and toxic elements in Hungarian honeys

The aim of this present study was determination of essential and toxic element concentrations in 34 mono- and multi-floral honey samples from four geographical regions of Hungary, and examination of the connection between the floral origin and the element content. Ten elements (Al, Ca, Cu, Fe, K, Mg, Mn, P, S and Zn) were identified by ICP-OES and six (As, Cd, Cr, Mo, Pb, Se) were analysed by ICP-MS. Potassium, calcium, and phosphorus were the most abundant elements with mean concentrations of 372, 47.9 and 44.3 mg kg(-1), respectively. The essential element content was very low in the analysed samples and generally below literature values. The concentrations of toxic elements were sufficiently low as to pose no risk to human health. The concentrations of aluminium, arsenic, cadmium and lead were low, with mean concentrations of 1028, 15.6, 0.746 and 45.5 μg kg(-1), respectively. Three honey groups (acacia, rape and sunflower) were distinguished by linear discriminant analysis from their element content.

Cisplatin administration influences on toxic and non-essential element metabolism in rats

Nowadays several papers deal with the effectiveness and side effects of metal complexes, especially cisplatin, in cancer therapy. The excretion of essential metal elements from the body is a serious problem in the treatment, but there are no data concerning the distribution and metabolism of toxic and nonessential elements. Therefore our aim was to study the concentration of some of these elements after treatment with cisplatin. Male Wistar rats (n=20, 175-190 g) were randomly divided into 2 groups (n=10/group). The control group received 1% (w/v) methyl cellulose at 10 mL/kg body weight, p.o. by gastric gavage twice daily for 14 days, while cisplatin was injected i.p. in a single dose of 6.5 mg/kg body weight. Inductively coupled plasma optical emission spectrometry (ICP-OES) was used for measuring Al, B, Ba, Cr, Li, Ni, Pb, Pt, Sb, Si, Sn, Sr and V content in plasma, liver and kidney. Liver total scavenger capacity, diene conjugate content and malondialdehyde concentration were also determined. Cisplatin elevated the free radical reactions in the liver, although redox balance did not change significantly. According to the study it seems that the metabolism of Al, Ba, Cr, Ni, Pb, Sr were changed by the effect of cisplatin, and the most notable alterations were found for Al and Pb. Therefore, besides the toxic effect of and free radical induction by Pt, the side effects of increased levels of other toxic and non-essential elements have to be taken into consideration.

The long-term effect of zinc soil contamination on selected free amino acids playing an important role in plant adaptation to stress and senescence

Increased endogenous plant cytokinin (CK) content through transformation with an isopentyl transferase (ipt) gene has been associated with improved plant stress tolerance. The objective of this study is to determine amino acid changes associated with elevated CK production in ipt transgenic tobacco (Nicotiana tabacum L., cv. Wisconsin 38). Nontransformed (WT) and transformed tobacco plants with ipt gene controlled by senescence-activated promoter (SAG) were exposed to zinc soil contamination (tested levels Zn1=250, Zn2=500, Zn3=750 mg kg(-1) soil). The Zn effect on plant stress metabolism resulted in changes in levels of selected free amino acids playing an important role in adaptation to stress and plant senescence (alanine, leucine, proline, methionine and γ-aminobutyrate) and differed for transformed and nontransformed tobacco plants. Analyses of amino acids confirmed that SAG tobacco plants had improved zinc tolerance compared with the WT plants. The enhanced Zn tolerance of SAG plants was associated with the maintenance of accumulation of proline, methionine and γ-aminobutyrate. The concentrations of leucine and alanine did not show significant differences between plant lines.

The environmental characteristics of usage of coal gangue in bricking-making: a case study at Huainan, China

The behaviors of natural radionuclides and toxic elements during coal gangue brick making processes are described. A simulation experiment of coal gangue brick firing was carried out to evaluate the enrichments of natural radionuclides and volatilizations of elements. Simultaneous sampling of coal gangue and corresponding combustion product (slag) was performed. The radioactivities of the radionuclide were determined by high-purity germanium gamma ray spectrometer, and the concentrations of toxic elements were analyzed by ICP-MS. Results have shown that the level of natural radionuclides may not cause immediate or acute environmental impacts because the Raeq values and Hex (in the brick) are 345 Bq kg(-1) and 0.89, lower than the limit values of 370 Bq kg(-1) and 1, respectively. However, the Raeq and Hex values are near the limit values, their chronic-environmental and health impacts should be considered noteworthy. The elements found in the emission could be categorized into two types: non-volatilized elements (Co, Cr, Mn and V) and volatilized elements (As, Cd, Cu, Ni, Se, Sn and Zn). Understanding the behaviors of natural radionuclides and toxic elements during brick making processes is helpful for the assessment of their potential impacts to human health and the environment.