Lead, mercury, cadmium, chromium, nickel, copper, zinc, calcium, iron, manganese and chromium (VI) levels in Nigeria and United States of America cement dust

Impacts of PM2.5 exposure near cement facilities on human health and years of life lost: A case study in Brazil

Cement factories significantly contribute to atmospheric pollution by generating fine particulate matter (PM2.5), which can potentially increase the mortality risk. The lack of information on the health impacts of PM2.5 pollution from cement operations in Brazil prompted this investigation. We used corrected PM2.5 measurements from low-cost sensors from March 2021 to October 2022 in Rio Branco do Sul, city in the southern region of the country and home to Latin America's largest cement plant, to assess exposure data. Disability-adjusted life years (DALY) method was applied to estimate the years of life lost (YLL) and cost estimate due to deaths from non-accidental causes, cardiovascular and respiratory diseases. The total YLL attributable to PM2.5 concentration was estimated by calculating the attributable fraction (AF) through relative risk. We also collected PM2.5 using a Harvard impactor to evaluate health risks from toxic metals components. During the study period, the analysis of chemical characterization of PM2.5 showed enrichment factors for most elements and the possible influence of the calcination process facilities on the PM2.5 levels. The mean concentration of PM2.5 exceeded the annual WHO air quality guideline (AQG) level, accounted for 3.5%, 4.7%, and 4.3% of total YLL from all causes, cardiovascular, and respiratory diseases, which corresponded to 0.23 (95% CI: 0.17-0.26), 0.06 (95% CI: 0.05-0.07) and 0.03 (95% CI: 0.01-0.06) years loss in life expectancy, respectively. An indirect health cost attributable to PM2.5 resulted in US$ 1.4 million, equivalent to about 3.5% of the total local annual health costs in Rio Branco do Sul, underscoring the significant financial burden of PM2.5 exposures. The greatest economic loss was found in the male age group of 40-69 years and among those with cardiovascular disease, rather than those with respiratory disease. Despite this, the carcinogenic and non-carcinogenic risks from inhalation of hazardous elements were within safe ranges. This work demonstrated PurpleAir's potential for air quality and public health applications. Our findings indicate health and economic benefits from reducing PM2.5 levels by adopting WHO air pollution standards. The results can guide policies toward delivering more effective health care.

Effects of Mixtures of Emerging Pollutants and Drugs on Modulation of Biomarkers Related to Toxicity, Oxidative Stress, and Cancer

Background/Objectives: Over time, the scientific community has developed a growing interest in the effects of mixtures of different compounds, for which there is currently no established evidence or knowledge, in relation to certain categories of xenobiotics. It is well known that exposure to pollutants causes oxidative stress, resulting in the overproduction of reactive oxygen species (ROS), which can affect signaling pathways that regulate the cell cycle, apoptosis, energy balance, and cellular metabolism. The aim of this study was to investigate the effects of sub-lethal concentrations of mixtures of emerging pollutants and pharmaceuticals on the modulation of biomarkers related to toxicity, oxidative stress, and cancer. Methods: In this study, the hepatoma cell line HepG2 was exposed to increasing concentrations of polybrominated diphenyl ether 47 (BDE-47), cadmium chloride (CdCl2), and carbamazepine (CBZ), both individually and in mixtures, for 72 h to assess cytotoxicity using the MTT assay. The subsequent step, following the identification of the sub-lethal concentration, was to investigate the effects of exposure at the gene expression level, through the evaluation of molecular markers related to cell cycle and apoptosis (p53), oxidative stress (NRF2), conjugation and detoxification of xenobiotics (CYP2C9 and GST), DNA damage (RAD51 and γH2AFX), and SUMOylation processes (SUMO1 and UBC9) in order to identify any potential alterations in pathways that are normally activated at the cellular level. Results: The results showed that contaminants tend to affect the enzymatic detoxification and antioxidant system, influencing DNA repair defense mechanisms involved in resistance to oxidative stress. The combined effect of the compounds at sub-lethal doses results in a greater activation of these pathways compared to exposure to each compound alone, thereby exacerbating their cytotoxicity. Conclusions: The biomarkers analyzed could contribute to the definition of early warning markers useful for environmental monitoring, while simultaneously providing insight into the toxicity and hazard levels of these substances in the environment and associated health risks.

Cadmium neurotoxicity: Insights into behavioral effect and neurodegenerative diseases

Cadmium (Cd) induced neurotoxicity has become a growing concern due to its potential adverse effects on the Central Nervous System. Cd is a Heavy Metal (HM) that is released into the environment, through several industrial processes. It poses a risk to the health of the community by polluting air, water, and soil. Cd builds up in the brain and other neural tissues, raising concerns about its effect on the nervous system due to its prolonged biological half-life. Cd can enter into the neurons, hence increasing the production of Reactive Oxygen Species (ROS) in them and impairing their antioxidant defenses. Cd disrupts the Calcium (Ca2+) balance in neurons, affects the function of the mitochondria, and triggers cell death pathways. As a result of these pathways, the path to the development of many neurological diseases affected by environmental factors, especially Cd, such as Alzheimer's Disease (AD) and Amyotrophic Lateral Sclerosis (ALS) is facilitated. There are cognitive deficits associated with long exposure to Cd. Memory disorders are present in both animals and humans. Cd alters the brain's function and performance in critical periods. There are lifelong consequences of Cd exposure during critical brain development stages. The susceptibility to neurotoxic effects is increased by interactions with a variety of risk factors. Cd poses risks to neuronal function and behavior, potentially contributing to neurodegenerative diseases like Parkinson's disease (PD) and AD as well as cognitive issues. This article offers a comprehensive overview of Cd-induced neurotoxicity, encompassing risk assessment, adverse effect levels, and illuminating intricate pathways.

Mechanism of Mitochondrial Kinetic Imbalance and Nrf2 Signaling Pathway-Mediated Oxidative Stress in Nickel and/or Chromium-Induced Kidney Injury in Mice

Nickel and chromium are both common heavy metals that pose serious environmental and health hazards. However, the exact mechanism by which nickel and/or chromium cause renal injury is unclear. Therefore, we explored the molecular mechanisms of renal injury caused by nickel and/or chromium poisoning from the perspective of mitochondrial dynamics and the Nrf2 antioxidant pathway. In this study, eighty 6-week-old C57BL/6J mice were randomly divided into four groups: control (Con, untreated), nickel (Ni, 110 mg/L Ni2+), chromium (Cr, 50 mg/L Cr6+), and combined nickel-chromium (Ni + Cr, 110 mg/L Ni2+, 50 mg/L Cr6+). The results showed that chronic nickel and/or chromium exposure inhibited body weight gain and impaired kidney function and structure in mice. Chronic nickel and/or chromium exposure led to the disruption of mitochondrial dynamics and thus induced oxidative stress. On the other hand, the Nrf2 antioxidant pathway may play an important regulatory role in mitigating oxidative stress-induced oxidative damage in kidney. The present study partially elucidated the molecular mechanism of renal injury induced by nickel and/or chromium exposure in mice and the regulatory role of the Nrf2 pathway in inducing oxidative injury from the perspective of mitochondrial dynamics. This provides a theoretical basis for the development of prevention and control strategies, and environmental protection measures.

Increased cancer risk in HIV-infected individuals occupationally exposed to chemicals: Depression of p53 as the key driver

The growing exposure to occupational chemicals and the spread of human immunodeficiency virus (HIV) infection are major global health issues. However, there is little data on the carcinogenic risk profile of HIV-infected individuals who have been occupationally exposed to chemical mixtures. This study therefore investigated the levels of cancer risk biomarkers in HIV-infected individuals exposed to occupational chemicals, exploring the relationship between apoptotic regulatory and oxidative response markers as a measure of cancer risk. Study participants (mean age 38.35±0.72 years) were divided into four groups according to their HIV status and occupational chemical exposure: 62 HIV-positive exposed (HPE), 66 HIV-positive unexposed (HPU), 60 HIV-negative exposed (HNE), and 60 HIV-negative unexposed (HNU). Serum p53, β-cell lymphoma-2 (bcl2), 8-hydroxydeoxyguanosine (8-OHdG), superoxide dismutase (SOD), and malondialdehyde (MDA) were measured using standard methods. Clusters of differentiation 4 (CD4+) T-lymphocytes were enumerated using flow cytometry. Serum p53 and bcl2 levels in HPE (0.91±0.11ng/ml and 122.37±15.77ng/ml) were significantly lower than HNU (1.49±0.15ng/ml and 225.52±33.67ng/ml) (p < 0.05), respectively. Wildtype p53 and bcl2 were positively and significantly correlated with 8-OHdG (r = 0.35, p<0.001; r = 0.36, p<0.001) and SOD (r = 0.38, p<0.001; r = 0.39, p<0.001). After controlling for gender, age, BMI, and cigarette smoking, both HIV status and SOD activity were significantly associated with wildtype p53 and bcl2 (p < 0.05). Malondialdehyde was significantly higher in the HPE (0.72 ± 0.01 mg/ml) than in the HNE (0.68 ± 0.01 mg/ml) and HNU (0.67 ± 0.01 mg/ml) groups (p < 0.05). The HPE group showed significantly lower CD4 counts than the HNE and HNU groups. Individuals who are HIV-infected and occupationally exposed to chemicals have a constellation of depressed immunity, elevated oxidative stress, and loss of tumour suppressive functions, which together intensify cancer risk, providing valuable scientific and public health bases for preventive measures in this vulnerable population.

Impact of cement waste on soil fertility and crop productivity: a serious concern for food security

The rapid expansion of urbanization and construction activities has led to a significant increase in cement production worldwide, resulting in a surge in cement waste generation. This study aims to provide a comprehensive analysis of the repercussions of cement waste on soil fertility and crop productivity, emphasizing its critical implications for global food security. Through a multidisciplinary approach, encompassing field surveys, laboratory experiments, and statistical modeling, we assess the physicochemical alterations induced by cement waste in agricultural soils. Our findings reveal substantial declines in crucial soil parameters, including pH levels, organic matter content, and nutrient availability, which directly translate into diminished crop yields. Furthermore, the study identifies key mechanisms underlying these detrimental effects, including altered microbial communities and disrupted nutrient cycling processes. In addition, the findings underscore the severity of the issue, revealing substantial declines in soil fertility and crop yields in areas affected by cement waste contamination. Additionally, we discuss potential mitigation strategies and policy interventions aimed at mitigating the adverse effects of cement waste on agricultural systems. By quantifying the extent of soil degradation and crop yield reduction attributed to cement waste, this research underscores the urgency for sustainable waste management practices and highlights the need for policy interventions to safeguard agricultural productivity and ensure global food security in the face of escalating urbanization and construction activities.

Red Cell Distribution Width and Mean Corpuscular Volume Alterations: Detecting Inflammation Early in Occupational Cement Dust Exposure

Introduction Cement dust emitted during cement manufacture consists of toxic components. Occupational cement dust exposure may cause inflammation in the human body, which may be detected early by observing changes in blood parameters such as red blood cell distribution width (RDW) and mean corpuscular volume (MCV). Objectives The study aims to observe the effect of occupational cement dust exposure on RDW and MCV. Methods This study was performed in the Department of Physiology of Dhaka Medical College, Dhaka, Bangladesh, and a factory in Munshiganj, Bangladesh, from September 2017 to August 2018. Ninety-two participants between 20 and 50 years were included (46 subjects were occupationally exposed to cement dust, and 46 were not exposed to cement dust). A pre-designed questionnaire was used for data collection. An independent sample t-test was used to analyze basic information, such as blood pressure and BMI. The multivariate regression model was used to analyze the effect of cement dust exposure on the study group. The impact of cement dust exposure duration was analyzed using the multivariate regression model. The level of significance was p < 0.05. The statistical analysis was performed using STATA-15 (StataCorp, College Station, TX), and the graphical presentation used GraphPad Prism v8.3.2. Results The cement dust-exposed participants had a significantly higher value of MCV by 1.19 fi (95% CI = 0.02, 4.84; p = 0.049) and a 5.92% increase in RDW (95% CI = 5.29, 6.55; p < 0.001) than that of the control group. Conclusion The study reveals that exposure to cement dust causes significant changes in RDW and MCV. These changes may indicate hemolysis due to inflammation.

Applying machine learning random forest (RF) method in predicting the cement products with a co-processing of input materials: Optimizing the hyperparameters

Co-processing recycled waste during cement production, i.e., using alternative materials such as secondary raw materials or secondary raw fuels, is widely practiced in developed countries. Alternative raw materials or fuels contain high concentrations of heavy metals and other hazardous chemicals, which might lead to the potential for dangerous heavy metals and hazardous chemicals to be transferred to clinker or cement products, resulting in exposure and emissions to people or the environment. Managing input materials and predicting which inputs affect the final concentration is essential to prevent potential hazards. We used the data of six heavy metals by input raw materials and input fuels of cement manufacturers in 2016-2017. The concentrations of Pb and Cu in cement were about 10-200 times and 4 to 200 times higher than other heavy metals (Cr, As, Cd, Hg), respectively. We profiled the influence of heavy metal concentration of each input material using the principal component analysis (PCA), which analyzed the leading causes of each heavy metal. The Random Forest (RF) ensemble model predicted cement heavy metal concentrations according to input materials. In the case of Cu, Cd, and Cr, the training performance showed R square values of 0.71, 0.71, and 0.92, respectively, as a result of predicting the cement heavy metal concentration according to the heavy metal concentration of each cement input material using the RF model, which is a machine learning model. The results of this study show that the RF model can be used to predict the amount and concentration of alternative raw materials and alternative fuels by controlling the concentration of heavy metals in cement through the concentration of heavy metals in the input materials.

Assessment of sources and health risks of heavy metals in metropolitan household dust among preschool children: The LEAPP-HIT study

The most common construction material used in Taiwan is concrete, potentially contaminated by geologic heavy metals (HMs). Younger children spend much time indoors, increasing HM exposure risks from household dust owing to their behaviors. We evaluated arsenic (As), cadmium (Cd), and lead (Pb) concentrations in fingernails among 280 preschoolers between 2017 and 2023. We also analyzed HM concentrations, including As, Cd, Pb, chromium (Cr), nickel (Ni), copper (Cu), zinc (Zn), iron (Fe), and manganese (Mn), in 90 household dust and 50 road dust samples from a residential area where children lived between 2019 and 2021 to deepen the understanding of sources and health risks of exposure to HMs from household dust. The average As, Cd, and Pb concentrations in fingernails were 0.12 ± 0.06, 0.05 ± 0.05, and 0.95 ± 0.77 μg/g, respectively. Soil parent materials, indoor construction activities, vehicle emissions, and mixed indoor combustion were the pollution sources of HMs in household dust. Higher Cr and Pb levels in household dust may pose non-carcinogenic risks to preschoolers. Addressing indoor construction and soil parent materials sources is vital for children's health. The finding of the present survey can be used for indoor environmental management to reduce the risks of HM exposure and avoid potential adverse health effects for younger children.

Monte Carlo-based probabilistic risk assessment for cement workers exposed to heavy metals in cement dust

This study assessed the carcinogenic and non-carcinogenic health risks of cement plant workers exposed to chromium (Cr), arsenic (As), cadmium (Cd), and lead (Pb) in cement dust using a probabilistic approach. Air samples were collected according to NIOSH 7900 and OSHA ID-121 methods and analyzed by an graphite furnace atomic absorption spectrometer. The EPA inhalation risk assessment model and Monte Carlo simulation were utilized to assess the health risks. Sensitivity analysis was used to determine the influencing parameters on health risk. The average concentrations of As and Pb exceeded the occupational exposure limit (OEL), reaching a maximum of 3.4 and 1.7 times the OEL, respectively, in the cement mill. Individual metals' cancer risk exceeded the 1E-4 threshold in ascending order of Cd < As < Cr. The mean cancer risk of Cr ranged from 835E-4 (in raw mill) to 2870E-4 (in pre-heater and kiln). Except for Cd, the non-cancer risk of metals exceeded the standard (hazard index, HQ = 1) in the ascending order of Pb < As < Cr. The mean HQ of Cr ranged from 162.13 (in raw mill) to 558.73 (in pre-heater and kiln). After adjusting for control factors, the cancer and non-cancer risks remained over the respective recommended levels. Sensitivity analysis revealed that the concentration of Cr was the most influential parameter on both carcinogenic (78.5%) and non-carcinogenic (88.06%) risks. To protect the health of cement factory employees, it is recommended to minimize cement dust emissions, implement job rotation, and use raw materials with low levels of heavy metals.

An environmentally friendly approach for the characterization of construction materials: determination of trace, minor, and major elements by slurry sampling high-resolution continuum source graphite furnace atomic absorption spectrometry

A slurry sampling method was developed for the fast determination of Pb, Ni, Fe, and Mn in construction materials by high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GFAAS). For sample introduction into the GF, stable slurries were prepared by sonicating 10 mg of ground solid sample in 10.0 mL of 1% (v/v) Triton X-100 and 1% (v/v) HNO₃ solution for 1.0 min. The determination of the four elements was carried out in three measurement runs, with Ni and Fe being determined simultaneously. The HR-CS GFAAS measurements were performed using analytical lines with adequate sensitivity, considering the content of each element in the material: Pb at 283.306 nm (42%), Mn at 403.080 nm (6.7%), Ni at 232.003 nm (100%) and Fe at 232.036 nm (1.4%). The pyrolysis and atomization temperatures and the use of chemical modifiers were optimized using both aqueous standards and slurry samples. At optimal conditions, samples with concentrations of Pb from 1.5 to 80 μg g^-1, Ni from 4.0 to 75 μg g^-1, Mn from 2.0 to 600 μg g^-1, and Fe from 0.15 to 60 mg g^-1 could be determined using a unique sample suspension. To assess the validity of the method, a fly ash certified reference material (CRM) was analysed using the slurry sampling HR-CS GFAAS method; this CRM and the construction material samples were also analysed by HR-CS GFAAS after the digestion of the samples. The obtained results using both methods were statistically comparable (Student's paired t-test for two independent methods at a 95% confidence level) demonstrating the suitability of the proposed method.

Metal pollution and potential human health risk assessment in major seafood items (fish, crustaceans, and cephalopods)

Global seafood consumers are increasingly concerned about and prefer safe, high-quality, and hazard-free seafood products. This study investigated various Pakistani processing plants supplying the international market and explored commercially important seafood species (fish, crustaceans, and cephalopods) for metal content, contamination, and potential health risks. The results showed that the metal concentrations differed significantly among species. The metals loads were as Fe > Cu > Zn > Mn > Pb > Ni > Cd > Hg. Contamination factor (CF), pollution load index (PLI), and metal pollution index (MPI), verified negligible contamination of seafood. As assessed by the estimated daily intake, target hazard quotient, hazard index, and carcinogenic risk, the potential human health risks associated with the contaminated seafood were lower than the perceived threat. In conclusion, seafood processing plants export products that meet international food safety standards and are safe for consumers worldwide.

Heterogeneous Variations on Historical and Future Trends of CO2 and Multiple Air Pollutants from the Cement Production Process in China: Emission Inventory, Spatial-Temporal Characteristics, and Scenario Projections

Cement production is a major contributor to carbon dioxide (CO₂) and multiple hazardous air pollutant (HAP) emissions, threatening climate mitigation and urban/regional air quality improvement. In this study, we established a comprehensive emission inventory by coupling the unit-based bottom-up and mass balance methods, revealing that emissions of most HAPs have been remarkably controlled. However, an increasing 6.0% of atmospheric mercury emissions, as well as 14.1 and 23.7% of fuel-related and process-related CO₂ emission growth were witnessed unexpectedly. Industrial adjustment policies have imposed a great impact on the spatiotemporal changes in emission characteristics. Monthly emissions of CO₂ and multiple HAPs decreased from December to February due to the "staggered peak production," especially in northern China after implementing the intensified action plan for air pollution control in winter. Upgrading environmental technologies and adjusting capacity structures are identified as dominant driving forces for reducing HAP emissions. Besides, energy intensity improvement can help offset some of the impact caused by the increase in clinker/cement production. Furthermore, scenario analysis results show that ultra-low emission and low-carbon technology transformation constitute the keys to achieve the synergic reduction of CO₂ and multiple HAP emissions in the future.

Relationships between House Characteristics and Exposures to Metal(loid)s and Synthetic Organic Contaminants Evaluated Using Settled Indoor Dust

This study investigates associations between house characteristics and chemical contaminants in house dust, collected under the nationally representative Canadian House Dust Study (2007−2010). Vacuum samples (<80 µm fraction) were analysed for over 200 synthetic organic compounds and metal(loid)s. Spearman rank correlations between contaminant concentrations in dust and presence of children and pets, types of flooring, heating styles and other characteristics suggested a number of indoor sources, pointing to future research directions. Numerous synthetic organics were significantly associated with reported use of room deodorizers and with the presence of cats in the home. Hardwood flooring, which is a manufactured wood product, emerged as a source of metal(loid)s, phthalates, organophosphate flame retardants/plasticizers, and obsolete organochlorine pesticides such as ∑DDT (but not halogenated flame retardants). Many metal(loid)s were significantly correlated with flame-retardant compounds used in building materials and heating systems. Components of heating appliances and heat distribution systems appeared to contribute heat-resistant chemicals and alloys to settled dust. Carpets displayed a dual role as both a source and repository of dust-borne contaminants. Contaminant loadings (<80 µm fraction) were significantly elevated in heavily carpeted homes, particularly those located near industry. Depending on the chemical (and its source), the results show that increased dust mass loading may enrich or dilute chemical concentrations in dust. Research is needed to improve the characterisation of hidden indoor sources such as flame retardants used in building materials and heating systems, or undisclosed ingredients used in common household products, such as air fresheners and products used for companion animals.

Determination of Total Mercury and Carbon in a National Baseline Study of Urban House Dust

Mercury (Hg) is one of the top ten chemicals of concern for public health, according to the World Health Organization. This study investigates Hg concentrations in house dust collected from urban single family homes, to better understand typical indoor residential exposures. Using direct solid sample analysis, total Hg and carbon (TC) were determined in the <80 µm fraction of settled dust samples collected under the Canadian House Dust Study. Hg concentrations displayed a log-normal distribution with median/geomean of 0.68/0.70 mg/kg (n = 995). A small subset (<1%) of homes exhibited anomalously high dust Hg concentrations (>9.0 mg/kg). A comparison of Hg concentrations in fresh dust and household vacuum dust collected from the same homes indicated no significant difference in the two sampling methods. Total carbon concentrations displayed a median/geomean of 29.3/28.5% (n = 1011). A significant correlation between total Hg and TC in house dust (p < 0.00001) reflects the association between Hg and organic carbon previously observed in soil and sediments. The results of this study indicate a 10-fold enrichment in house dust compared with the average background concentrations reported for soil and sediments (0.07 mg/kg). The observed enrichment is attributable to Hg emissions from indoor sources and/or Hg carried home from occupational sources.

Sources and composition of metals in indoor house dust in a mid-size Canadian city

House dust is an important medium for exposure to persistent pollutants, such as metals. Detailed characterization of metal composition is needed to identify sources and potential health impacts of exposure. In this study we show that specific metals in dust dominate in different locations within residential homes in a mid-size Canadian city (Fort McMurray, Alberta), up to two years after a major wildfire event in 2016. Dust samples were collected in high-traffic (e.g. bedroom, N = 186), low-traffic (e.g. basement, N = 158), and entranceway areas (N = 171) of residential homes (N = 125), and analyzed for 25 trace metal elements using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The profile of metal concentrations in the entranceway resembled that of outdoor soils, especially for crustal elements. On the other hand, Cu, Zn, and Pb concentrations in dust sampled in indoor living areas were on average three to six times higher than in other indoor locations indicating indoor sources for these elements. In general, Pb concentrations were similar or lower than in an average Canadian residence, but a substantial fraction showed anomalously high concentrations in the low-traffic areas, particularly on concrete surfaces in basements. Notably, the 2016 wildfires showed limited influence on metal concentrations in indoor dust, despite the widespread concerns in the community about long term exposure. Enrichment factor ratio calculations and principal component analysis showed two classes of sources of metals in dust that represent geogenic-outdoor sources and anthropogenic-indoor sources. Overall, we demonstrate that outdoor and indoor sources of dust impact its composition, and these influences are reflected in the different areas of a home.

Evaluating source-oriented human health risk of potentially toxic elements: A new exploration of multiple age groups division

Effective source-oriented human health risk assessment (HHRA) for people in different life stages will guide pollution control and risk prevention. This work integrated three receptor models of positive matrix factorization, Unmix, and factor analysis with nonnegative constraints for accurate source-oriented HHRA of potentially toxic elements in 6 age groups of populations (0-<1 year, 1-<6 years, 6-<12 years, 12-<18 years, 18-<44 years, and 44+ years). Four sources were identified. Natural source controlled As, Cr, and Ni in dust and soil as well as Pb and Zn in soil. Industrial-traffic emissions contributed most of Cd in dust and soil as well as Pb and Zn in dust. Hg in both dust and soil originated from coal combustion. Construction works contributed more to PTEs in soil than in dust. Noncarcinogenic and carcinogenic risk for both dust and soil changed in similar trends by age. The noncancer risk reduced with increasing age for people below 44 years. Carcinogenic risk of females over 44 years were the highest, while children from 0 to 1 year faced the lowest carcinogenic risk. Among the four origins of PTEs, natural sources contributed most to health risk of PTEs, followed by industrial-traffic sources, construction works, and coal combustion. Based on sequential Gaussian simulation (SGS), the susceptible population and risk areas were identified. Children from 0 to 6 years were identified as susceptible population. The areas with noncancer risk in dust were 19.15 km² for 0-<1 year and 3.14 km² for children from 1 to <6 years, and noncancer risk areas in soil were 30.26 km² for 0-<1 year and 0.85 km² for 1-<6 years. Relevant control and management works were demanded on children from 0 to 6 years and noncancer risk areas.

Fate of Lead and Cadmium in Precalciner Cement Plants and Their Atmospheric Releases

Disclosing the fate of lead (Pb) and cadmium (Cd) during the cement production process is the key to control their atmospheric emissions, which have not attracted much attention yet. In this study, three precalciner cement plants (CPs) using different raw materials in Guizhou Province in Southwest China were investigated. It showed that the concentrations of Pb and Cd in different raw materials and the associated total metal input of these materials were different among CPs; the behavior of Pb and Cd were almost the same during the clinker production process that there has been no accumulation of these two elements inside the system, and nearly all input of Pb and Cd were discharged by the clinker. Although the temperature of clinkerization was pretty high of 1450 °C, the atmospheric emission ratio of both metals was negligible (<0.006% for Pb and <0.002% for Cd of the total output, respectively); the main reason might be that the two elements were incorporated into the minerals of clinker, either as silicate or sulfate. The long-term environmental impacts of some high Pb-and Cd-laden clinkers and cement need to be monitored and evaluated.

Bioaccumulation of heavy metals in Stachys inflata and Scariola orientalis affected by particulate matters of a cement factory in central Iran

Industrial activities can affect accumulation of pollutants (e.g., heavy metals (HMs)) by plants and influence their entrance to the food chain. This research was carried out on accumulation of HMs including chromium (Cr), lead (Pb), and zinc (Zn) by two plants Stachys inflata and Scariola orientalis grown in natural grasslands in vicinity of a national park where they are influenced by dispersion of particulate matter (PM) through Sarooj Cement Factory in central Iran. The PM spatial dispersion of the factory was determined using the AERMOD model. Soil and vegetation samples were collected based on the modeled PM levels to analyze their HM contents. Bioconcentration factor (BCF) and transfer factor (TF) from root to shoot were determined in two widespread plants of the region: Stachys inflata and Scariola orientalis. The mean concentration of HMs in the soil samples was as follows: Zn (145.39 mg/kg) > Pb (78.52 mg/kg) > Cr (32.69 mg/kg) which was significantly correlated with simulated PM concentrations. This indicated the common source and distribution pattern of HMs which affected their accumulation in plants. TF and BCF values of the HMs were higher in Scariola orientalis than those of Stachys inflata, especially for Cr showing potentially higher risk to enter the food chain. The results showed that HM concentration in the soil as well as their accumulation by plants were correlated with the simulated PM deposition and not with linear distance from the factory.

Standardized experimental model for cement dust exposure; tissue heavy metal bioaccumulation and pulmonary pathological changes in rats

•

Exposure model is a reliable method of studying pulmonary toxicity of aerosolized xenobiotics.

•

Deposition of particles beyond the conducting zone and tissue bioaccumulation accompany exposure to cement dust (ECD).

•

Histoarchitectural alteration, body-organ weight discordance are indicators of acute ECD.

A controlled experimental model of exposure to aerosols particularly for cement dust was recently invented in a study from the laboratory that found high serum levels of heavy metals, decrease gastrointestinal motility, and altered hematological variables in cement dust exposed rats. However, reproducibility was not considered. This work aims at standardizing the model and investigating preliminary toxicological indicators. Thirty male rats used in this study were divided into 3 groups (n = 10). Group 1; control, while groups 2 and 3 were exposed to cement dust for 14 days and 28 days respectively. We assessed clinical signs of toxicity, tissue heavy metal concentration, histopathological, and body weight (BW) changes. We observed poor movement coordination, abnormal posture, cephalic fur loss. Evidence of ischemia and fibrotic pneumoconiosis were grossly observed in the lungs of the exposed groups. There was a significant increase in tissue level of heavy metals with pulmonary and gastric heavy metal content showing a trendy relationship during the period of the exposure as the value of Lead, Chromium, Cadmium, Iron, Calcium, and Nickel increased by nearly similar percentages in both tissues. Organs weights increased; the 14-day exposed (198 ± 31; 168 ± 22) and 28-day exposed (198 ± 22; 187 ± 26) groups had significantly reduced body weight at the first and second weeks of exposure compared to the control group (265 ± 26; 357 ± 40) respectively. Exposure to cement dust induced low bone density in the exposed rats (p < 0.05). Histopathological alterations include necrosis, inflammatory cellular infiltration, and alveolar hyperplasia suggestive of the proliferative response of pulmonary tissue to the dust. The operation of the standardized apparatus mimics a typical occupational exposure and the findings show that cement dust induces systemic toxicity via respiratory perturbation and body/organ weight discordance mediated by heavy metal bioaccumulation.

Elevated blood lead and metal/metalloid levels and environmental exposure sources in urban Ecuadorian school-age children and mothers

BACKGROUND

Lead and other toxic and potentially toxic metals and metalloids are significant contributors to the global burden of disease and disability. Studies characterizing blood metal/metalloid levels and potential sources of environmental exposures are limited for populations living in the major urban centers of Andean-area countries.

METHODS

We used ICP-MS to quantify blood levels of lead (PbB), cadmium (CdB), manganese (MnB), total arsenic (AsB), and total mercury (HgB) in school-age children (n = 47) and their reproductive-age mothers (n = 49) from low-resource households in Quito, Ecuador. These were compared to published 95th percentile reference values (RV95) and for PbB, also to CDC reference values. We used a detailed environmental questionnaire to examine the contribution of residential and neighborhood environmental exposure sources with participant blood metal/metalloid levels. We used ICP-MS to measure Pb levels in residential windowsill dust, floor dust, and drinking water samples and used XRF for paint samples.

RESULTS

Forty-five percent of the mothers had PbBs ≥ 5 μg/dL; 14.3% had PbBs ≥10 μg/dL. Maternal blood levels exceeded RV95s for PbB (76%), CdB (41%), MnB (88%), HgB (57%), and AsB (90%). Of children, 68% had PbBs ≥ 5 μg/dL, and 21.3% had PbB ≥10 μg/dL. Most child blood levels exceeded the RV95s for PbB (100%), CdB (100%), MnB (94%), and total HgB (94%) and AsB (98%). Most mothers (97%) and all children had blood levels indicating exposure to multiple metal/metalloid mixtures. Maternal and child PbBs were moderately correlated with each other but the other four metals/metalloids were not. Factors associated with maternal blood metal/metalloid levels were residence in a home with an earthen floor (PbB) or bare cement block walls (MnB), living near a dirt-paved or cobblestone street (PbB), <50 m from a heavily trafficked major roadway (PbB, HgB), living in the Los Chillos (PbB) or Cotocollao neighborhoods (PbB, HgB), or in areas where street vendors grilled food using charcoal (MnB). Factors associated with child blood metal/metalloid levels were residence in a dirt floor home (PbB, CdB, AsB), living near a dirt-paved or cobblestone street (PbB), living in the El Camal or Cotocollao neighborhoods (AsB), or in local neighborhoods where scrap metal smelters (MnB) and LPG gas depositories (PbB) were present.

CONCLUSIONS

The elevated blood levels of PbB, other metal/metalloids, and metal/metalloid mixtures identified mothers and children in this exploratory study is an urgent public health and clinical concern. The exposure patterns suggest that traffic-related exposures, especially the resuspension of legacy Pb in dust, as well as other anthropogenic and geogenic sources may be important environmental contributors to metal/metalloid exposures in urban Ecuadorian mothers and children. Future studies are needed to confirm these findings and explore other potential exposure sources. Biomonitoring is also needed in order to formulate effective intervention strategies to reduce population exposure to toxic levels of environmental metals/metalloids.

Potential risk of exposure to heavy metals from co-processing of secondary wastes in the Republic of Korea

The co-processing of secondary wastes during ordinary Portland cement (OPC) can result in high heavy metal concentrations in OPC products. However, earlier studies have not evaluated the concentrations of heavy metals (HMs) in OPC as a function of secondary input materials. Further, the health risk assessment (HRA) model has, thus far, has not been employed to assess the potential health risks associated with secondary raw materials and secondary fuels in OPC. Hence, to address these knowledge gaps, herein, monthly data for six HMs in the input materials and fuels from seven OPC manufacturers in the Republic of Korea were analyzed and modeled. Pb and Cu concentrations were found to be approximately 10-200 and 4-200 times higher than those of the other HMs, respectively. Furthermore, maximum Pb and Cu concentrations were 2-3 and 2-5 times higher than those reported in other countries, respectively. The quantity of input material had a significant influence on the observed patterns, and secondary raw materials, secondary additives, and secondary fuels were also determined to be important. Based on HRA assessment, although the risk levels were within permissible ranges, carcinogenic hazards attributable to Cr and Pb were not negligible. The results can aid in informed decision making and in implementing effective measures for managing risks associated with HMs in the OPC industry, thereby ameliorating threats to human health and environment.

Human health risk visualization of potentially toxic elements in farmland soil: A combined method of source and probability

Human health is adversely affected by potentially toxic elements (PTEs) in the topsoil, entering the bodies via inhalation, ingestion, and dermal contact. To visualize human health risks, we investigated five PTEs (Cd, As, Pb, Hg, and Cr) in 72 farmland topsoil samples from a town in Chongqing City, southwest China. Based on the human health risk assessment model, sequential indicator simulation (SIS) and the positive matrix factorization model (PMF) were used to construct the spatial health risks and to analyze the sources of PTEs; finally, health risks were combined with the source by ArcGIS. Based on our results, the use of SIS is feasible for the prediction of the spatial distribution of PTEs. Among the risks, the non-cancer risk of As for children most likely exceeded the accepted level in some areas, making As a priority pollutant. Although the health risks of soil Cd were acceptable in the region, the spatial probability distribution of Cd> 0.3 mg/kg represents a threat as Cd enters the human food chain. Even if the industrial discharge was the lowest individual contributor (29.33%), due to the impact of industrial discharge, the total non-cancer risk with a high probability (>0.85) for children still exceeded the accepted level in the northwestern area, which should be regarded as the priority pollution source. The combined method was useful to reduce efforts in environmental management, thus providing a basis for soil remediation and pollution source control.

Modeling the air pollutant concentration near a cement plant co-processing wastes

In this study, for the first time, we conducted full life-cycle studies on pollutants in a cement plant co-processing hazardous waste (HW) via the combined use of thermodynamic equilibrium calculations and the American Meteorological Society/Environmental Protection Regulatory Model. Results showed that the potential toxic elements (PTEs) can be classified into three categories: (1) non-volatized elements, Co; (2) semi-volatized elements, Cr and Ni; and (3) volatized elements, Cd, Pb and As. Besides, the spatial distributions of pollutants were strongly influenced by the prevalent wind direction and the size of the particulate matter they were absorbed on. The highest concentrations of most pollutants tended to be centralized at a distance in the range of 400 to 800 m away from the cement plant. Finally, validated results indicated that there is good agreement between the simulated and observed concentrations in this study. These findings can facilitate and assist local government authorities and policy makers with the management of urban air quality.

Renal bioaccumulation of trace elements in urban and rural Sri Lankan populations: A preliminary study based on post mortem tissue analysis

INTRODUCTION

Environmental pollution, especially by toxic trace elements, is a global health concern. Heavy metals such as Cadmium (Cd), Arsenic (As) and Lead (Pb) are associated with numerous disorders and are considered by some as an aetiological factor for the Chronic Kidney Disease (CKDu1) epidemic in Sri Lanka. This study explores patterns of bioaccumulation of six trace elements in kidneys obtained during forensic autopsies from urban and rural regions in Sri Lanka.

METHODS

Kidney samples obtained from one urban district (n = 13) and three rural districts (n = 18) were lyophilized, microwave digested and profiled by ICP-MS techniques.

RESULTS AND DISCUSSION

The mean age of the sampled population was 47.9 ± 11.3 yrs. Median (IQR) for Cd, As, Pb, Cr, Zn and Se were, 14.67(8.04-22.47) μg/g, 0.44(0.29-0.56) μg/g, 0.11(0.07-0.30) μg/g, 0.15(0.1096-0.3274), 25.55(17.24-39.35) μg/g and 0.52(0.37-0.84) μg/g, respectively. Cd, Zn and Se levels were significantly higher (p < 0.05) among the urban samples compared to that of the rural group. Zn and Se levels were higher among younger age groups. As, Pb and Cr did not show any significant differences between the two cohorts nor any correlations with age.

CONCLUSION

This population-specific baseline study provides an insight into the differences in exposure to toxic trace elements and essential elements between urban and rural populations. Residents in CKDu affected rural districts did not appear to be at risk of toxic heavy metal exposure, however their renal bioaccumulation of nephroprotective essential elements was lower than urban residents.

Isotope tracers for lead and strontium sources in the Tieguanyin tea garden soils and tea leaves

The concentrations of Pb & Sr in Tieguanyin tea leaves and soils from 15 tea gardens of Anxi, China, were determined and the sources of Pb & Sr in soil and leaf samples were analysed using isotope tracing technology. The results showed pH in soils had significant correlations to both acid-extractable Pb & Sr in soils and new leaves. The Pb concentration in leaves was significantly lower than that in soils, especially the acid-extractable Pb in soils. The low Bio-concentration Factor (BCF) indicated the bioavailable Pb in soils could not easily be transferred to leaves. The contribution rates of parent material were 61%-100% and 45%-100% for total Pb isotope and acid-extractable Pb isotope in soils, respectively, indicating a low impact of human activity. A sizeable influence of parent material for leaves was also observed, suggesting that Pb may be present in the dust-fall. Although Sr concentrations in leaves were not high, they exceeded that in soils. The high BCF also indicated that tea has a high capacity to accumulate Sr, with the coincidence that Sr⁸⁷/Sr⁸⁶ in the acid-extractable isotope in soils were similar to new leaves. A Pb-Sr joint tracer indicated that Sr in old and new leaves may be influenced by parent material and anthropogenic sources, respectively.

Heavy metal toxicity in the water column and benthic sediments of a degraded tropical stream

Agriculture and other anthropogenic activities on riparian corridors pose a great ecotoxicological risk to freshwater ecosystem and human health. Using the atomic absorption spectroscopy, concentrations of heavy metals (Cd, Cu, Fe, Zn, Pb and As) in the water column and benthic sediments of a degraded tropical stream (Opa Stream, Ile-Ife, Nigeria), were assessed with a view to determining the stream's health status. Three metals (Cu, Pb, and As) showed significant positive correlations between concentrations in the water column and the benthic sediments. All but one heavy metal (i.e. Zn) had reached disturbing concentrations in the stream's water column and exceeded their recommended limits in surface freshwaters. The geo-accumulation index (I_geo) and contamination factor (CF) indicated that the stream was moderately contaminated with Cd (0 <I_geo< 1; CF much closer to 1). This study concludes that the stream was impacted with heavy metals in its water column and slightly impacted with Cd on its bed, thus raising health concerns for plankton, benthic organisms and all users of the surface water. More conservation attention by relevant stakeholders through monitoring and regulation of human activities in river basins, is recommended for the sustenance of tropical freshwater ecosystem and human health.

Long-term impact of cement plant emissions on the elemental composition of both soils and pine stands and on the formation of Scots pine seeds

We investigated the long-term impact of the largest Russian cement plant on mesopodzol sandy soils and Scots pine stands. We determined the distributions of the total and available pools of Ca, Mg, K, Na, Mn, Fe, Zn, Ni, Cu, Pb and Cd in the soil profile to a depth of 60 cm (illuvial horizon) as well as the accumulation patterns of these elements in the vegetative and generative organs of Scots pine trees. High Ca accumulation in the impact zone soils was a result of CaO emissions by a cement plant. Also, CaO became the main cause of soil profile alkalization due to neutralization of soil acids and formation of calcium hydroxide or carbonates. Alkalization immobilized substantial amounts of Fe, Mn, Zn and Ni in the soil, reducing their availability. The most prominent effect of long-term cement production was a prominent Mn deficiency in vegetative and generative Scots pine organs due to the exhaustion of the available Mn pool in the illuvial horizon. The miniaturization of cones, a decrease in seed yield and a reduction in seed germinability were observed in the emission impact zones. Pretreatment of Mn-deficient seeds with manganese eliminated Mn deficiency but did not increase seed germination.

Heavy metal quantification of classroom dust in school environment and its impacts on children health from Rawang (Malaysia)

This study aimed to determine bioavailable heavy metal concentrations (As, Cd, Co, Cu, Cr, Ni, Pb, Zn) and their potential sources in classroom dust collected from children's hand palms in Rawang (Malaysia). This study also aimed to determine the association between bioavailable heavy metal concentration in classroom dust and children's respiratory symptoms. Health risk assessment (HRA) was applied to evaluate health risks (non-carcinogenic and carcinogenic) due to heavy metals in classroom dust. The mean of bioavailable heavy metal concentrations in classroom dust found on children's hand palms was shown in the following order: Zn (1.25E + 01 μg/g) > Cu (9.59E-01 μg/g) > Ni (5.34E-01 μg/g) > Cr (4.72E-02 μg/g) > Co (2.34E-02 μg/g) > As (1.77E-02 μg/g) > Cd (9.60E-03 μg/g) > Pb (5.00E-03 μg/g). Hierarchical cluster analysis has clustered 17 sampling locations into three clusters, whereby cluster 1 (S3, S4, S6, S15) located in residential areas and near to roads exposed to vehicle emissions, cluster 2 (S10, S12, S9, S7) located near Rawang town and cluster 3 (S13, S16, S1, S2, S8, S14, S11, S17, S5) located near industrial, residential and plantation areas. Emissions from vehicles, plantations and industrial activities were found as the main sources of heavy metals in classroom dust in Rawang. There is no association found between bioavailable heavy metal concentrations and respiratory symptoms, except for Cu (OR = 0.03). Health risks (non-carcinogenic and carcinogenic risks) indicated that there are no potential non-carcinogenic and carcinogenic risks of heavy metals in classroom dust toward children health.

Cadmium induced damage in Wistar rats, ameliorative potentials of progesterone

Asides the increased human exposure to Cadmium containing products; the adverse effects of Cadmium on human health is further exacerbated by its toxicity at low dosage, long biologic half-life and low rate of excretion from the body. This study investigated the protective potential of progesterone on cadmium-induced damage in Wistar rats. Adult male Wistar rats received CdCl₂ once daily for 21 days. Progesterone was given 30 min. after administration of CdCl₂ while 3 other groups were given distilled water, CdCl₂ and progesterone alone. Blood samples were collected from the animals for the determination of liver function and antioxidant status while the liver, kidney, cerebellar and hippocampal tissues were excised and fixed in Neutral buffered formalin for histopathological studies. While Cadmium caused changes in liver function parameters which were indicative of oxidative stress, pre-treatment with progesterone caused restoration to values which were non-significant to the control. Similar findings were made for G6PD, GSH, SOD, CAT and MDA. Histopathology revealed tissue damage in the Cd treated group; this was attenuated by prior treatment with progesterone. Progesterone ameliorated the free radical induced oxidative stress and tissue injury arising from exposure to Cadmium; attention should be given to its antioxidant role in Cadmium toxicity.

Main components of PM10 in an area influenced by a cement plant in Catalonia, Spain: Seasonal and daily variations

Particulate matter (PM) composition has a key role in a wide range of health outcomes, such as asthma, chronic obstructive pulmonary disease, lung cancer, cardiovascular disease, and death, among others. Montcada i Reixac, a municipality located in the Barcelona metropolitan area (Catalonia, Spain), for its location and orography, is an interesting case- study to investigate air pollution. The area is also characterized by the presence of different industrial emission sources, including a cement factory and a large waste management plant, as well as an intense traffic. In this study, PM₁₀ levels, trace elements, ions, and carbonaceous particles were determined for a long time period (2013-2016) in this highly polluted area. PM₁₀ samples were collected during six consecutive days in two campaigns (cold and warm) per year. A number of elements (As, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cs, Cu, Dy, Er, Eu, Fe, Ga, Gd, Ge, Hf, Hg, Ho, K, La, Li, Hg, Mg, Mn, Mo, Nb, Nd, Ni, Pb, Pr, Rb, Sb, Sc, Se, Sm, Sn, Sr, Tb, Th, Ti, Tl, U, V, W, Y, Yb, and Zr), ions (Cl^-, SO₄^2-, NO₃^-, and NH₄⁺), and carbonaceous content (total carbon, organic plus elemental carbon, and CO₃^2-), were analysed. These data were used to identify the PM₁₀ main components: mineral matter, sea spray, secondary inorganic aerosols, organic matter plus elemental carbon, trace elements or indeterminate fraction. Although a clear seasonality (cold vs. warm periods) was found, there were no differences between working days and weekends. Obviously, the cement plant influences the surrounding environment. However, no differences in trace elements related with the cement plant activity (Al, Ca, Ni and V) between weekdays and weekends were noted. However, some traffic-related elements (i.e., Co, Cr, Mn, and Sb) showed significantly higher concentrations in weekdays.

Assessment of blood levels of heavy metals including lead and manganese in healthy children living in the Katanga settlement of Kampala, Uganda

Background

Exposure to environmental heavy metals is common among African children. Although many of these metals are known neurotoxicants, to date, monitoring of this exposure is limited, even in countries such as Uganda that are undergoing rapid industrialization. An assessment of the burden and potential causes of metal exposure is a critical first step in gauging the public health burden of metal exposure and in guiding its elimination.

Methods

In May 2016, we enrolled 100 children between the ages of 6 and 59 months living in the Katanga urban settlement of Kampala, Uganda. We measured whole blood concentrations of antimony, arsenic, barium, cadmium, cesium, chromium, cobalt, copper, lead, manganese, nickel, selenium, and zinc. Applying reference cutoffs, we identified metals whose prevalence of elevated blood concentrations was > 10%. We also administered an environmental questionnaire to each child’s caregiver to assess potential exposures, including source of drinking water, cooking location and fuel, materials used for roof, walls, and floor, and proximity to potential pollution sources such as main roads, garbage landfills, and fuel stations. We compared log-transformed blood metal concentrations by exposure category, using t-test for dichotomous comparisons and ANOVA for comparisons of three categories, using Tukeys test to adjust for multiple comparisons.

Results

The prevalence of high blood levels was elevated for six of the metals: antimony (99%), copper (12%), cadmium (17%), cobalt (19.2%), lead (97%), and manganese (36.4%). Higher blood manganese was significantly associated with having cement walls (p = 0.04) or floors (p = 0.04). Cadmium was greater among children who attended school (< 0.01), and cobalt was higher among children who lived near a garbage landfill (p = 0.01).

Conclusions

Heavy metal exposure is prevalent in the Katanga settlement and may limit neurodevelopment of children living there. Future studies are needed to definitively identify the sources of exposure and to correct potential nutritional deficiencies that may worsen metal absorption.

Electronic supplementary material

The online version of this article (10.1186/s12889-018-5589-0) contains supplementary material, which is available to authorized users.

Study on Cr(VI) Leaching from Cement and Cement Composites

This paper reports an experimental study on hexavalent chromium leaching from cement samples and cement composites containing silica fume and zeolite additions that were subjected to various leaching agents. The water-soluble Cr(VI) concentrations in cements ranged from 0.2 to 3.2 mg/kg and represented only 1.8% of the total chromium content. The presence of chromium compounds with both chromium oxidation states of III and VI was detected in the cement samples by X-ray photoelectron spectroscopy (XPS). Leaching tests were performed in a Britton-Robinson buffer to simulate natural conditions and showed increased dissolution of Cr(VI) up to 6 mg/kg. The highest amount of leached hexavalent chromium was detected after leaching in HCl. The findings revealed that the leaching of chromium from cements was higher by 55⁻80% than that from the cement composites. A minimum concentration was observed for all cement samples when studying the relationship between the soluble Cr(VI) and the cement storage time.

The role of forest in mitigating the impact of atmospheric dust pollution in a mixed landscape

Atmospheric dust pollution, especially particulate matter below 2.5 μm, causes 3.3 million premature deaths per year worldwide. Although pollution sources are increasingly well known, the role of ecosystems in mitigating their impact is still poorly known. Our objective was to investigate the role of forests located in the surrounding of industrial and urban areas in reducing atmospheric dust pollution. This was tested using lichen transplants as biomonitors in a Mediterranean regional area with high levels of dry deposition. After a multivariate analysis, we have modeled the maximum pollution load expected for each site taking into consideration nearby pollutant sources. The difference between maximum expected pollution load and the observed values was explained by the deposition in nearby forests. Both the dust pollution and the ameliorating effect of forested areas were then mapped. The results showed that forest located nearby pollution sources plays an important role in reducing atmospheric dust pollution, highlighting their importance in the provision of the ecosystem service of air purification.

Leaf structural traits of tropical woody species resistant to cement dust

Cement industries located nearby limestone outcrops in Brazil have contributed to the coating of cement dust over native plant species. However, little is known about the extent of the response of tropical woody plants to such environmental pollutant particularly during the first stages of plant development and establishment. This work focused on the investigation of possible alterations in leaf structural and ultrastructural traits of 5-month-old Guazuma ulmifolia Lam. (Malvaceae), 6-month-old Myracrodruon urundeuva Allemão (Anacardiaceae), and 9-month-old Trichilia hirta L. (Meliaceae) challenged superficially with cement dust during new leaf development. Leaf surface of plants, the soil or both (leaf plus soil), were treated (or not) for 60 days, under controlled conditions, with cement dust at 2.5 or 5.0 mg cm(-2). After exposure, no significant structural changes were observed in plant leaves. Also, no plant death was recorded by the end of the experiment. There was also some evidence of localized leaf necrosis in G. ulmifolia and T. hirta, leaf curling in M. urundeuva and T. hirta, and bulges formation on epidermal surface of T. hirta, after cement dust contact with plant shoots. All species studied exhibited stomata obliteration while T. hirta, in particular, presented early leaf abscission, changes in cellular relief, and organization and content of midrib cells. No significant ultrastructural alterations were detected under the experimental conditions studied. Indeed, mesophyll cells presented plastids with intact membrane systems. The high plant survival rates, together with mild morphoanatomic traits alterations in leaves, indicate that G. ulmifolia is more resistant to cement dust pollutant, followed by M. urundeuva and T. hirta. Thus, the three plant species are promising for being used to revegetate areas impacted by cement industries activities.

The partitioning behavior of trace element and its distribution in the surrounding soil of a cement plant integrated utilization of hazardous wastes

In the present study, the trace elements partitioning behavior during cement manufacture process were systemically investigated as well as their distribution behaviors in the soil surrounding a cement plant using hazardous waste as raw materials. In addition to the experimental analysis, the thermodynamic equilibrium calculations were simultaneously conducted. The results demonstrate that in the industrial-scale cement manufacture process, the trace elements can be classified into three groups according to their releasing behaviors. Hg is recognized as a highly volatile element, which almost totally partitions into the vapor phase. Co, Cu, Mn, V, and Cr are considered to be non-volatile elements, which are largely incorporated into the clinker. Meanwhile, Cd, Ba, As, Ni, Pb, and Zn can be classified into semi-volatile elements, as they are trapped into clinker to various degrees. Furthermore, the trace elements emitted into the flue gas can be adsorbed onto the fine particles, transport and deposit in the soil, and it is clarified here that the soil around the cement plant is moderately polluted by Cd, slightly polluted by As, Cr, Ba, Zn, yet rarely influenced by Co, Mn, Ni, Cu, Hg, and V elements. It was also estimated that the addition of wastes can efficiently reduce the consumption of raw materials and energy. The deciphered results can thus provide important insights for estimating the environmental impacts of the cement plant on its surroundings by utilizing wastes as raw materials.

Dependence among total polyphenols content, total antioxidant capacity and heavy metals content in potatoes

Polyphenols belong to the most significant compounds with antioxidant effects in potatoes. Their content depends on several factors. The most important factor is the variety of potatoes and the conditions of their growing such as temperature, rainfall, altitude, agronomic and chemical characteristics of the soil. We have compared two potato cultivars in the study which have been grown in the Slovak localities Dolné Obdokovce and Vrbová nad Váhom (cv. Agria) and Nitra, Radošina and Vrbová nad Váhom (cv. Impala). In lyophilized samples of potatoes total polyphenols content in ethanolic extracts using Folin-Ciocalteu agens and in methanolic extracts total antioxidant capacity using DPPH were spectrophotometrically determined. The average total polyphenols content in the potato variety Impala was 604.26 ±120.70 mg.kg-1 dry matter (DM) and 529.37 ±59.35 mg.kg-1 DM in the variety Agria. The average value of total antioxidant capacity, expressed in % inhibition, was 8.44 ±1.68% in the potato variety Impala and 8.09 ±1.14% in Agria. The results obtained were evaluated by One-way analysis of variance ANOVA (LSD-test), using Statistical Analysis Software Statgraphics. Mutual correlations among the total polyphenols content, total antioxidant capacity and heavy metals concent (Pb, Ni, Cd - determined using atomic absorption spectrometry (AAS) method: Cd, Pb: GF-AAS and Ni F-AAS) were evaluated using the correlation and regression analysis (Microsoft Excel). Statistically significant interdependence (p <0.05) was only confirmed between the Cd content and total antioxidant capacity in both cultivars, or between the Ni content and total antioxidant capacity in the variety Impala.

Elevated prenatal methylmercury exposure in Nigeria: evidence from maternal and cord blood

Methylmercury is a neurodevelopmental toxicant that is globally distributed though little is known about prenatal exposures in sub-Saharan Africa. The objective of the current study was to measure total mercury levels in cord blood and maternal blood from 95 mother-newborn pairs recruited from hospitals in Nnewi, Nigeria. The secondary aims of the study were to explore if demographic and dietary factors were associated with blood mercury levels, and to explore if mercury levels were associated with any self-reported health outcome and childbirth outcome. Maternal blood mercury levels averaged 3.6 μg L(-1) and ranged from 1.1 μg L(-1) to 9.5 μg L(-1). Cord blood mercury averaged 5.1 μg L(-1) and ranged from 1.2 μg L(-1) to 10.6 μg L(-1). The mean ratio of mercury in paired cord blood to maternal blood was 1.5 and it ranged from 0.4 to 3.2. Mercury in maternal and cord blood were significantly correlated (r=0.471). More than one-third of mothers reported eating fish at least once per day, and a weak (p=0.08) fish consumption-related increase in blood mercury was found. Cord blood mercury was positively and significantly associated with birth weight and length, and head and chest circumference. Mercury levels in 36% of the participants exceeded the biomonitoring guideline associated with the United States Environmental Protection Agency (U.S. EPA) reference dose for mercury. The study shows that pregnant women and their newborns are exposed to methylmercury and that their exposures are higher compared to general populations sampled from other regions of the world.

The effectiveness of the stabilization/solidification process on the leachability and toxicity of the tannery sludge chromium

A stabilization/solidification (S/S) process by using cement was applied to tannery sludge in order to find a safer way of landfilling this waste. The effects of three parameters on the process effectiveness were analysed in terms of leachate toxicity and chromium retention (%). The parameters studied were the relative amount of added water (30-50 wt.%), cement (10-60 wt.% in the solid components), and the use of three different types of cement (clinker with additions of limestone, with additions of limestone and fly ashes, and with additions of pozzolans). Statistical analysis performed by variance analysis and categorical multifactorial tests reveals that all the studied parameters significantly influence the effectiveness of the process. Results showed that chromium retention decreases as the relative amount of cement and water increases, probably due to additional chromium provided by cement and increased in the porosity of the mixtures. Leachate toxicity showed the same minimum value for mixtures with 30% or 40% cement, depending on the type of cement, showing that clinker is the main material responsible for the process effectiveness, and additives (pozzolans or fly ashes) do not improve it. The volume increase is lower as less sludge is replaced by cement and the relative amount of water decreases, and for the cement without additions of fly ashes or pozzolans. Therefore, the latter seems to be the most appropriate cement in spite of being more expensive. This is due to the fact that the minimum toxicity value is achieved with a lower amount of cement; and moreover, the volume increase in the mixtures is lower, minimizing the disposal cost to a landfill.

Particles internalization, oxidative stress, apoptosis and pro-inflammatory cytokines in alveolar macrophages exposed to cement dust

Exposure to cement dust is one of the most common occupational dust exposures worldwide, but the mechanism of toxicity has not been fully elucidated. Cement dust (N) and clinker (C) samples collected from Nigeria and another sample of cement dust (U) collected from USA were evaluated using alveolar macrophage (NR8383) cell culture to determine the contribution of different sources of cement dust in the severity of cement dust toxicity. Cement dust particles internalization and morphologic alterations using transmission electron microscopy (TEM), cytotoxicity, apoptotic cells induction, intracellular reactive oxygen species generation, glutathione reduction, TNF-α, IL-1β, and CINC-3 secretion in alveolar macrophages (NR8383) exposed to cement dust and clinker samples were determined. Particles were internalized into the cytoplasmic vacuoles, with cells exposed to U showing increased cell membrane blebbing. Also, NR8383 exposed to U show more significant ROS generation, apoptotic cells induction and decreased glutathione. Interleukin-1β and TNF-α secretion were significantly more in cells exposed to both cement dust samples compared with clinker, while CINC-3 secretion was significantly more in cells exposed to clinker (p < 0.05). Endocytosis, oxidative stress induced-apoptosis and induction of pro-inflammatory cytokines may be key mechanisms of cement dust immunotoxicity in the lung and toxicity may be factory dependent.