Metalloid Research Articles

Long-term monitoring of exposure to toxic and essential metals and metalloids in the tawny owl (Strix aluco): Temporal trends and influence of spatial patterns

As a result of regulatory decisions, atmospheric deposition of most toxic metals and metalloids (MEs) has decreased in Europe over the past few decades. However, little is known about how this reduction translates into exposure at higher trophic levels in the terrestrial environment where temporal trends may be spatially heterogeneous due to local current or legacy sources of emissions (e.g., industry) or long-range transport of elements (e.g., marine transport). The aim of this study was to characterize temporal and spatial trends of exposure to MEs in terrestrial food webs using a predatory bird, the tawny owl Strix aluco, as a biomonitor. Toxic (Al, As, Cd, Hg, Pb) and essential/beneficial (B, Co, Cu, Mn, Se) elemental concentrations were measured in feathers of nest-captured females from 1986 to 2016, extending a previous study published over the time-series 1986–2005 (n = 1051), in a breeding population in Norway. A drastic decline over time was shown for the toxic MEs (−97 % for Pb, −89 % for Cd, −48 % for Al, and −43 % for As) except Hg. The beneficial elements B, Mn, and Se showed oscillations but an overall decline (−86 %, −34 %, and −12 %, respectively) whereas the essentials Co and Cu did not exhibit significant trends. The distance to potential sources of contamination influenced both the spatial patterns of concentrations in owl feathers and their temporal trends. The accumulation of As, Cd, Co, Mn and Pb was overall higher in the vicinity of sites recorded as polluted, and a greater temporal decrease of As, B, and Cd concentrations was found in the areas of further distance to polluted sites. The decrease of Pb concentrations was sharper further from the coast during the 1980s than in coastal areas, while the opposite was observed for Mn. The levels of Hg and Se were higher in coastal areas, and Hg temporal trends differed according to the distance to the coast. This study highlights the valuable insights provided by long-term survey of wildlife exposure to pollutants and landscape indicators to reveal regional or local patterns and detect unexpected events, data that are crucial for regulation and conservation of ecosystem health.

Biochar, Ochre, and Manure Maturation in an Acidic Technosol Helps Stabilize As and Pb in Soil and Allows Its Vegetation by Salix triandra

Past mining extraction activities still have a negative impact in the present time, the resulting metal(loid) contaminated soils affecting both the environment and human health. Assisted phytostabilization technology, combining soil conditioner application to immobilize metal(loid)s and plant growth to reduce erosion and leaching risks, is a useful strategy in the restoration of metal(loid) contaminated lands. However, contaminants will respond differently to a particular amendment, having their own specific characteristics. Therefore, in multi-contaminated soils, soil conditioner combination has been suggested as a good strategy for metal(loid) immobilization. In the present study, in a mesocosm experiment, organic (biochar and manure) and inorganic (ochre) amendments were evaluated in single and combined applications for their effect on metal(loid) stabilization and Salix triandra growth improvement, in an arsenic and lead highly contaminated soil. Specifically, the effects of these amendments on soil properties, metal(loid) behavior, and plant growth were evaluated after they aged in the soil for 6 months. Results showed that all amendments, except biochar alone, could reduce soil acidity, with the best outcomes obtained with the three amendments combined. The combination of the three soil conditioners has also led to reducing soil lead availability. However, only ochre, alone or combined with the other soil fertilizers, was capable of immobilizing arsenic. Moreover, amendment application enhanced plant growth, without affecting arsenic accumulation. On the contrary, plants grown on all the amended soils, except plants grown on soil added with manure alone, showed higher lead concentration in leaves, which poses a risk of return of lead into the soil when leaves will shed in autumn. Considering that the best plant growth improvement, together with the lowest increase in lead aerial accumulation, was observed in manure-treated soil, the addition of manure seems to have potential in the restoration of arsenic and lead contaminated soil.

Characterization of metal(loid)s and antibiotic resistance in bacteria of human gut microbiota from chronic kidney disease subjects

BackgroundHuman Gut Microbiota (HGM) is composed of more than one thousand species, playing an important role in the health status of individuals. Dysbiosis (an HGM imbalance) is augmented as chronic kidney disease (CKD) progresses, as loss of kidney function accelerates. Increased antibiotic use in CKD subjects and consumption of nephrotoxic heavy metals and metalloids such as lead, cadmium, arsenic, and mercury in tap water increases the dysbiosis state. Studies in people with stage 3 CKD are complex to carry out, mainly because patients are self-reliant who rarely consult a specialist. The current work focused on this type of patient.ResultsLead and arsenic-resistant bacteria were obtained from self-reliant (that stands on its own) stage 3 CKD subjects. Pathogen-related Firmicutes and Proteobacteria genus bacteria were observed. Resistance and potentiation of antibiotic effects in the presence of metal(loid)s in vitro were found. Furthermore, the presence of the following genes markers for antibiotic and metal(loid) resistance were identified by qPCR: oxa10, qnrB1, mphB, ermB, mefE1, arr2, sulll, tetA, floR, strB, dhfr1, acrB, cadA2k, cadA3k, arsC, pbrA. We observed a decrease in the number of metal resistance markers.ConclusionsThe presence of cadA and arsC genetic markers of antibiotics and metal(loid)s resistance were detected in samples from stage 3 CKD subjects. Lower gene amplification in advanced stages of CKD were also observed, possibly associated with a decrease in resident HGM during kidney disease progression.

Risk of heavy metal(loid)s, morphology, and mineral composition in atmospheric dustfall from university campuses in Wuhan, China

Risk of heavy metal(loid)s, morphology, and mineral composition in atmospheric dustfall from university campuses in Wuhan, China

Spatio-temporal monitoring of mercury and other stable metal(loid)s and radionuclides in a Croatian terrestrial ecosystem around a natural gas treatment plant.

The natural gas industry bears a certain contamination risk to human and biota due to, among others, mercury, arsenic, and naturally occurring radioactive material content in gas. We tracked multiple stabile metal(loid)s and radionuclides within the natural gas treatment plant Molve, Croatia, ecosystem during the last decade through a comprehensive monitoring of soil, earthworms, moss, livestock (blood, milk, hair, urine, and feces from cows), and wildlife animals (brain, muscle, liver, and kidney of European hare and pheasant). The level of mercury and other stable metal(loid)s has shown temporal variation, but without an obvious trend. The found spatial differences in soil and earthworms were based on the differing soil characteristics of the sampled locations and exceeded the maximal allowable concentration of arsenic and zinc for agricultural soil. The status of essential copper, selenium, and zinc in cows, hares, and pheasants inclined towards deficiency. The measured stable metal(loid) levels in soil and animal samples were generally in the same range of values reported in earlier decades from the same area or non-polluted areas across Europe. The consumption of local cow and game products (e.g., milk, meat) can be considered safe for human health, although game offal is advised to be avoided as a food item due to the low risk of lead and cadmium's adverse effects. Although the activity concentrations of some radionuclides in moss were higher than reported for pristine areas, transfer from soil to moss was assessed as average (except for lead-210). Radiological risk to human and biota around the gas treatment plant Molve was estimated as negligible.

Design of Pb(II)-Specific E. coli-Based Biosensors by Engineering Regulatory Proteins and Host Cells.

Bacterial cell-based biosensors have been widely developed for detecting environmental toxic materials. The znt-operon in Escherichia coli is a Zn(II)-responsive genetic system and is employed in Zn(II), Cd(II), and Hg(II)-sensing biosensors. In this study, point mutations were introduced in the regulatory protein ZntR to modulate its target selectivity, and metal ion-exporting genes, such as copA and zntA, in host cells were deleted to increase cellular metal ion levels and enhance specificity. Thus, the overall responses of the E. coli cell-based biosensors toward metal(loid) ions were increased, and their selectivity, which was originally for Cd(II) and Hg(II), was shifted to Pb(II). The gene encoding ZntA, known as the Zn(II)-translocating P-type ATPase, showed an impact on the ability of E. coli to export Pb(II), whereas copA deletion showed no significant impact. Noteworthily, the newly generated biosensors employing ZntR Cys115Ile showed the capacity to detect under 5 nM Pb(II) in solution, without response to other tested metal ions within 0–100 nM. To understand the marked effect of single point mutations on ZntR, computational modeling was employed. Although it did not provide clear answers, changes in the sequences of the metal-binding loops of ZntR modulated its transcriptional strength and target selectivity. In summary, the approaches proposed in this study can be valuable to generate new target-sensing biosensors with superior selectivity and specificity, which can in turn broaden the applicability of cell-based biosensors to monitor Pb(II) in environmental systems.

Comparative Spatial Assessment of Trace Metal(loid) Pollution in the Sediments of the Lower Olifants River Basin in South Africa

Globally, many freshwater ecosystems are facing chemical pollution from both natural and anthropogenic sources. The Olifants River Basin in South Africa is experiencing degradation due to mining, industrial, agricultural, and domestic activities. The impacts of these activities coupled with climate change is likely to shift the hydrological cycle that may increase accumulation of toxic chemicals in the sediments. The aim of the study was to assess the contamination of As, Cr, Cu, Fe, Mn, Ni, Pb, and Zn in the sediments collected at the upstream, midstream and downstream of four rivers of the Lower Olifants River Basin; the Blyde, Mohalpitsi, Ga-Selati, and Steelpoort rivers. The highest concentrations of most of the trace metal (loid)s assessed were from the Steelpoort River followed by the Blyde River. Significant differences in metal concentrations were found across study sites and rivers. The overall assessment of the sub-catchment, which is characterised mainly by mining and agricultural activities shows significantly elevated levels of As, Cr, Mn, and Ni in the sediments and may cause secondary pollution in the water. Using enrichment factor (EF) and geo-accumulation index (Igeo), some of the sediments were severely enriched and extremely contaminated respectively with As, Cr, and Ni. This may risk the lives of aquatic biota and humans, especially rural communities that rely on these rivers for drinking water. The findings provide baseline information for effective management control of metal(loid) pollution in the Olifants River Basin.

SANTORY: SANTORini’s Seafloor Volcanic ObservatorY

Submarine hydrothermal systems along active volcanic ridges and arcs are highly dynamic, responding to both oceanographic (e.g., currents, tides) and deep-seated geological forcing (e.g., magma eruption, seismicity, hydrothermalism, and crustal deformation, etc.). In particular, volcanic and hydrothermal activity may also pose profoundly negative societal impacts (tsunamis, the release of climate-relevant gases and toxic metal(loid)s). These risks are particularly significant in shallow (<1000m) coastal environments, as demonstrated by the January 2022 submarine paroxysmal eruption by the Hunga Tonga-Hunga Ha’apai Volcano that destroyed part of the island, and the October 2011 submarine eruption of El Hierro (Canary Islands) that caused vigorous upwelling, floating lava bombs, and natural seawater acidification. Volcanic hazards may be posed by the Kolumbo submarine volcano, which is part of the subduction-related Hellenic Volcanic Arc at the intersection between the Eurasian and African tectonic plates. There, the Kolumbo submarine volcano, 7 km NE of Santorini and part of Santorini’s volcanic complex, hosts an active hydrothermal vent field (HVF) on its crater floor (~500m b.s.l.), which degasses boiling CO2–dominated fluids at high temperatures (~265°C) with a clear mantle signature. Kolumbo’s HVF hosts actively forming seafloor massive sulfide deposits with high contents of potentially toxic, volatile metal(loid)s (As, Sb, Pb, Ag, Hg, and Tl). The proximity to highly populated/tourist areas at Santorini poses significant risks. However, we have limited knowledge of the potential impacts of this type of magmatic and hydrothermal activity, including those from magmatic gases and seismicity. To better evaluate such risks the activity of the submarine system must be continuously monitored with multidisciplinary and high resolution instrumentation as part of an in-situ observatory supported by discrete sampling and measurements. This paper is a design study that describes a new long-term seafloor observatory that will be installed within the Kolumbo volcano, including cutting-edge and innovative marine-technology that integrates hyperspectral imaging, temperature sensors, a radiation spectrometer, fluid/gas samplers, and pressure gauges. These instruments will be integrated into a hazard monitoring platform aimed at identifying the precursors of potentially disastrous explosive volcanic eruptions, earthquakes, landslides of the hydrothermally weakened volcanic edifice and the release of potentially toxic elements into the water column.

Decision Pattern for Changing Polluted Areas into Recreational Places

There are many enclaves in the Mediterranean basin with soils contaminated with heavy metal(loid)s, most of these in natural areas of great beauty that have suffered the consequences of industrial and mining activity for years. These soils pose a risk to human and animal health due to the transfer of metal(loid)s condemning these areas to isolation. The rehabilitation by means of phytoremediation is one of the most used techniques, but phytoremediation must be part of a comprehensive strategy of steps that guide owners and administrations in the recovery of ecosystem services. An easily replicable decision-making methodology is defined, considering the initial conditions, the preferences of the decision makers or typologies from among six possibilities and the different models of use, typified in 13 categories. As a result, a landscape is obtained that integrates phytostabilization and areas with recreational and/or educational uses. Two case studies from the southeast of Spain are presented as validation, a deposit of mining sludge residues and the channel of a river contaminated by industrial discharges. Both enclaves are included in the tourist and cultural offer of their area, thus achieving an environmental and socioeconomic benefit and have been visited by more than 1000 people in a two-year period.

Analyzing pesticides and metal(loid)s in imported tobacco to Saudi Arabia and risk assessment of inhalation exposure to certain metals

Exposure to toxic chemicals through smoked tobacco is a significant global public health issue due to their genotoxic and carcinogenic properties. The study aims to (1) measure Arsenic (As), Cadmium (Cd), Cobalt (Co), Chromium (Cr), Mercury (Hg), Nickle (Ni), lead (Pb), and 407 pesticides in tobacco commercialized in Saudi Arabia; and (2) evaluate human health risks associated with smoking tobacco. Thus, we analyzed 60 tobacco samples per brand from eight of the most popular tobacco brands in the Saudi market. The analyzed tobacco contained significant concentrations of toxic metal (loid)s and banned pesticides. Twenty-three out of 407 pesticide residues were found, with an average concentration of 0.004–1.155 µg/g. Average concentrations of As, Cd, Co, Cr, Hg, Ni, and Pb for all brands were 0.16, 0.57, 0.75, 1.36, 1.94, 0.01, and 0.37 µg/g, respectively. The risk assessment indicated that high cancer risks are associated with exposure to As, Cd, Cr, and Ni, while lower risks are associated with Pb. Additionally, the potential cancer risk estimated for Cr was higher than other toxic elements. The cumulative cancer risks (95%) under three different cases for all brands were greater than the permissible limits (=10−4). The chances of getting cancer through inhalation of particulate As, Cd, Cr, Ni, and Pb was 4 in 10 000 cases in the best case scenario (1 cigarette per day). Therefore, metal content in cigarette tobacco should be reduced to improve public health. HIGHLIGHTS All tested brands contained banned pesticide residues except for brand C. Tobacco samples contained significant concentrations of toxic metal(loid)s. A high risk of developing cancer is associated with exposure to As, Cd, Cr, and Ni, while a lower risk is associated with exposure to Pb.

Iron nanoparticles to recover a co-contaminated soil with Cr and PCBs

Little attention has been given to the development of remediation strategies for soils polluted with mixture of pollution (metal(loid)s and organic compounds). The present study evaluates the effectiveness of different types of commercial iron nanoparticles (nanoscale zero valent iron (nZVI), bimetallic nZVI-Pd, and nano-magnetite (nFe3O4)), for the remediation of an industrial soil co-contaminated with Cr and PCBs. Soil samples were mixed with nZVI, nZVI-Pd, or nFe3O4 at doses selected according to their reactivity with PCBs, homogenized, saturated with water and incubated at controlled conditions for 15, 45 and 70 days. For each sampling time, PCBs and chromium were analyzed in aqueous and soil fractions. Cr(VI) and Cr leachability (TCLP test) were determined in the soil samples. The treatment with the three types of iron nanoparticles showed significant reduction in Cr concentration in aqueous extracts at the three sampling times (> 98%), compared to the control samples. The leachability of Cr in treated soil samples also decreased and was stable throughout the experiment. Results suggested that nZVI and nZVI-Pd immobilized Cr through adsorption of Cr(VI) on the shell and reduction to Cr(III). The mechanism of interaction of nFe3O4 and Cr(VI) included adsorption and reduction although its reducing character was lower than those of ZVI nanoparticles. PCBs significantly decreased in soil samples (up to 68%), after 15 days of treatment with the three types of nanoparticles. However, nFe3O4 evidenced reversible adsorption of PCBs after 45 days. In general, nZVI-Pd reduced PCB concentration in soil faster than nZVI. Control soils showed a similar reduction in PCBs concentration as those obtained with nZVI and nZVI-Pd after a longer time (45 days). This is likely due to natural bioremediation, although it was not effective for Cr remediation. Results suggest that the addition of nZVI or nZVI-Pd and pseudo-anaerobic conditions could be used for the recovery of soil co-contaminated with Cr and PCBs.

Genome-wide in silico analysis indicates the involvement of OsSWEET transporters in abiotic and heavy metal (loid) stress responses in rice

Genome-wide in silico analysis indicates the involvement of OsSWEET transporters in abiotic and heavy metal (loid) stress responses in rice

Application of Biochar for the Restoration of Metal(loid)s Contaminated Soils

Biochar has recently aroused great interest for the restoration of contaminated soils since it improves soil properties and induces the immobilization of pollutants. This study evaluates the use of biochar from plant pruning, applied as an amendment, for immobilizing metal(loid)s in a highly contaminated soil as well as for reducing the phytotoxicity of these pollutants by promoting natural revegetation. For this purpose, a bioassay with Trifolium pratense L. was used to test the effectiveness of the soil amendment in greenhouse conditions. Three treatments were carried out including soil contaminated with metal(loid)s (RA), and this soil was amended with biochar at different dosage: 4% (RA4B) and 8% (RA8B). A non-contaminated soil (NC) from a nearby area not affected by contamination was used as a control. The results show that biochar increased soil pH by several units depending on the dose used, 8% being the most effective one. Biochar treatments also reduced soluble and bioavailable forms of Zn and Cu. Likewise, phytotoxicity was significantly reduced, promoting seed germination and biomass with plant growth values similar to the non-polluted soil. In light of the results obtained, the evaluation of the bioremediation potential of biochar under field conditions can be considered.

Health Risk Assessment From Heavy Metals Derived From Drinking Water and Rice, and Correlation With CKDu

Rice is the staple food of most Asians, including Sri Lankans. It is cultivated extensively in the dry zonal regions in Sri Lanka such as the Polonnaruwa district, where the prevalence of chronic kidney disease of unknown etiology (CKDu) is higher. We investigated the concentrations of potentially toxic heavy metal(loid)s in groundwater and locally produced rice and correlated their exposure with the prevalence of CKDu. We studied human health exposure risks such as total daily intake (TDI), hazard quotient, hazard index, and carcinogenic risk (CR) from the consumption of groundwater and rice. In well-water, the concentrations of heavy metal(loid)s, cadmium (Cd), arsenic (As), and lead (Pb) were below the World Health Organization (WHO) stipulated allowable limits. Except for Pb, contents of other heavy metal(loid) in all rice samples were lower than maximum permissible limits by the WHO (0.02 mg/kg). Twenty-three per cent (23%) of rice samples analyzed exceeded the permissible limit for TDI of Pb, and analysis of hazard index for Cd, As, and Pb revealed 26% of rice samples could result in a health risk through the consumption of rice in this population. Further, the outcome depicted no CR of Cd, As, and Pb by consuming rice in this study area. We recommended further studies and investigations to minimize or eliminate potential risks from chronic Pb exposure to consumers.

Health risks of adults in Hong Kong related to inhalation of particle-bound heavy metal(loid)s

Heterogeneity between ambient and personal exposure to heavy metals has been documented. However, few studies have investigated potential health risks posed by inhalational exposure to airborne heavy metal(loid)s at the individual level. A total of 404 personal fine particles (PM2.5) samples were collected from 61 adult residents (aged 18–63 years) in Hong Kong during 2014–2015. Heavy metal(loid)s were analyzed using energy dispersive X-ray fluorescence. Among the analyzed heavy metal(loid)s, zinc (Zn) was the most abundant component in personal PM2.5, followed by lead (Pb), copper (Cu), and vanadium (V); cobalt (Co) and cadmium (Cd) were not detectable. Health risks of personal exposure to heavy metal(loid)s via inhalation were assessed for adults, including non-cancer risks that were characterized by hazard quotient (HQ) and hazard index (HI). The results indicated that non-cancer risks of heavy metal(loid)s were attributable to Cu, with a 95th HQ value > 1. Arsenic (As) and hexavalent chromium [Cr (VI)] were also significant contributors to inhalation cancer risks (> 1 × 10−6) for the adult participants. Finally, we employed a Monte Carlo simulation to evaluate the uncertainty associated with health risk assessment. The mean and median upper-bound lifetime cancer risk associated with inhalation exposure to carcinogenic heavy metal(loid)s exceeded the acceptable level (1 × 10−6) for adults. Traffic emission (including non-tailpipe exhaust), shipping emission, and regional pollution were significant sources of heavy metals. These findings suggest that emission controls targeting local vehicles and vessels should be given priority in Hong Kong.

Alfalfa Biochar Supported Mg-Fe Layered Double Hydroxide as Filter Media to Remove Trace Metal(Loid)S from Stormwater

Alfalfa Biochar Supported Mg-Fe Layered Double Hydroxide as Filter Media to Remove Trace Metal(Loid)S from Stormwater

Risks for Using FeCl3 Under a Submerged Condition, and Different Water Management to Reduce Uptake of Antimony and Cadmium in a Rice Plant

Soil pollution by multiple metal(loid)s is a common problem, and it is not easy to synchronously reduce their uptake in crops. Compounds containing iron (Fe) are often used to efficiently remediate soil metal(loid) pollution; however, its associated risks did not receive much attention especially under unsuitable soil water conditions. Pot experiments were set up using an antimony (Sb) and cadmium (Cd) co-contaminated soil treated with a continued submergence condition plus 5, 10, or 20 mg kg−1 FeCl3 (Experiment I), or treated with different water management including submergence, intermittent irrigation, and dry farming (Experiment II). Our results showed that the continued submergence resulted in excessive accumulation of arsenic (As) in different tissues of rice plants even if the soil As background concentration is low. High soil moisture content increased the available concentrations of Sb and As, but reduced that of Cd in rhizosphere soils, which was in line with their concentrations in different tissues of rice plants (Experiment II). Under a continued submergence condition, FeCl3 significantly stimulated As concentration in the shoots, roots (excluded Fe20 treatment), and husks, but reduced it in the grains. FeCl3 reduced Sb concentration only in the roots and grains, and reduced Cd concentration only in the husks, suggesting a limited efficiency of FeCl3 to reduce Cd uptake under a submergence condition. In this study, the dynamic changes of As, Sb, and Cd concentrations in soil solution, their available concentrations in rhizosphere soils, their accumulation in root iron/manganese plaques, and the relationships among the above parameters were also discussed. We suggested that if FeCl3 would be used to remediate the contaminated soils by Sb and Cd, dry farming for a short time is needed to avoid As accumulation, and intermittent irrigation is a potential choice to avoid the excessive accumulation of As, Sb, and Cd in the edible parts of rice plants.

Distribution and ecological risk of heavy metal(loid)s in surface sediments of the Hai Phong coastal area, North Vietnam

ABSTRACT Surface sediment samples were collected from the Hai Phong coastal area, and grain size and heavy metal content were analyzed to estimate the effects of natural and anthropogenic activities. The area comprised five sediment types: fine sand, very fine sand, very coarse silt, coarse silt, and medium silt. Ten heavy metal(loid)s (Fe, Cu, Pb, Zn, Cd, As, Cr, Co, Mn, Mo) were assessed. The average concentration of followed the order of Fe > Mn > Zn > Pb > Cu > Cr > As > Co > Mo > Cd. Cu, Pb, and As were over Interim Sediment Quality Guideline (ISQGs), while Cr, Zn, and Cd were below ISQG levels. Three sediment groups with three levels of heavy metal(loid)s were identified: group 1 was distributed in the river and nearshore, with coarse silt and the highest heavy metal(loid) concentration; group 2 was distributed in the river, nearshore, and offshore, with very coarse silt and high heavy metal concentrations; and group 3 was distributed in the river and offshore, with very fine sand and the lowest heavy metal concentrations. Runoff from the mainland had a significant effect with a high contamination of As, Cu, and Pb in Hai Phong coastal area.

Assessment of sediment arsenic and iron occurrence and leaching potential in a potable water treatment plant wastewater stabilization pond system

Wastewater stabilization ponds (WSPs) are commonly used to reduce wastewater metal(loid) concentrations from drinking water treatment plants (DWTPs) through sedimentation. However, this results in increased sediment concentrations that can be released back into the overlying water. Thus, our goal was to evaluate the WSP metal(loid)s occurrence and leaching potential. Currently, a Saskatchewan based DWTP’s WSP system was investigated given historically elevated effluent As and Fe concentrations. The WSP consists of five ponds that were sampled on six occasions in 2019 and 2020. In addition, sediments were used in laboratory-based experiments to determine their leaching potential. Overall, the sediments were found to contain elevated concentrations of As and Fe of 25 to 400 mg/kg and 10 000 to 45 000 mg/kg, respectively. Leaching experiments indicated that the pond sediments could potentially release As and Fe with log Kd values ranging from 2.21 to 4.31 L/kg, whereas Fe ranged from 3.32 to 5.53 L/kg.

A geostatistical approach to estimating source apportionment in urban and peri-urban soils using the Czech Republic as an example

Unhealthy soils in peri-urban and urban areas expose individuals to potentially toxic elements (PTEs), which have a significant influence on the health of children and adults. Hundred and fifteen (n = 115) soil samples were collected from the district of Frydek Mistek at a depth of 0–20 cm and measured for PTEs content using Inductively coupled plasma—optical emission spectroscopy. The Pearson correlation matrix of the eleven relevant cross-correlations suggested that the interaction between the metal(loids) ranged from moderate (0.541) correlation to high correlation (0.91). PTEs sources were calculated using parent receptor model positive matrix factorization (PMF) and hybridized geostatistical based receptor model such as ordinary kriging-positive matrix factorization (OK-PMF) and empirical Bayesian kriging-positive matrix factorization (EBK-PMF). Based on the source apportionment, geogenic, vehicular traffic, phosphate fertilizer, steel industry, atmospheric deposits, metal works, and waste disposal are the primary sources that contribute to soil pollution in peri-urban and urban areas. The receptor models employed in the study complemented each other. Comparatively, OK-PMF identified more PTEs in the factor loadings than EBK-PMF and PMF. The receptor models performance via support vector machine regression (SVMR) and multiple linear regression (MLR) using root mean square error (RMSE), R square (R2) and mean square error (MAE) suggested that EBK-PMF was optimal. The hybridized receptor model increased prediction efficiency and reduced error significantly. EBK-PMF is a robust receptor model that can assess environmental risks and controls to mitigate ecological performance.