Metal Loid Concentrations Research Articles

Biochemical and Elemental Composition of Pelagic Sargassum Biomass Harvested across the Caribbean

Massive and recurrent strandings of pelagic Sargassum biomass have become the new norm in the Caribbean and the Western Africa since 2011, and there is no sign of this abating. These Sargassum events have negative environmental, socioeconomic and health impacts in the affected countries. In the meantime, various processing techniques and applications have been suggested for valorisation of this biomass. However, variability in quantity, quality and location creates substantial uncertainty for the development of reliable and robust industrial processes. As part of ongoing efforts to better characterise seasonal and geographical variations in the biochemical and elemental composition of the pelagic Sargassum biomass across the Caribbean, we analysed samples from Mexico, Jamaica and the Dominican Republic harvested during summer 2020 and winter 2021. Different degrees of variation were observed in the contents of ash, metals and metalloids, vitamins, fatty acids, amino acids and biogenic amines, and monosaccharides. Our results indicate that biomass is of highly variable quality depending on season and location. In this context, we suggest that biorefinery approaches geared towards controlled metal removal and focused on the extraction and purification of amino acids, fatty acids and vitamins should be prioritised to assess the potential valorisation of pelagic Sargassum biomass into standardised and high-value outputs.

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.

Alfalfa (Medicago Sativa L.): Genotypic Diversity and Transgenic Alfalfa for Phytoremediation

Soil contamination caused by industrial and agricultural activities is an environmental problem that poses a serious risk to human health and the ecosystem. Persistent organic pollutants (POPs) are organic chemicals that persist in the environment for long periods because of their high resistance to photolytic, chemical, and biological degradation. Besides POPs, high concentrations of non-essential heavy metals and metalloids, such as arsenic, cadmium, and lead, are increasingly becoming a problem worldwide. Remediation strategies for organic and inorganic pollutants in the environment have received global attention. For organic or inorganic contaminants, phytoremediation is the strategy of choice because of a green technology that uses plants and solar energy to clean hyper-accumulated toxic pollutants from the environment. Some plant species have a high capacity to grow and survive in elevated levels of contaminants. With a long cultivation history and adaptability to a wide range of territories, alfalfa has not only widely been used for animal feed and a medicinal herb but is also an ideal natural resource and model plant for remediation of contaminated soils, offering a variety of elite characteristics. This review provides, firstly, abundant genomic information on the genetic diversity and population structure of alfalfa. Secondly, we focused on the transgenic alfalfa plants for enhanced phytoremediation of POPs, such as atrazine, polychlorinated biphenyl (PCB), and trichloroethylene (TCE), as well as phytoremediation of petroleum and heavy metals. Thirdly, the future perspective of enhancement of phytoremediation efficiency was discussed in depth. This review is intended to provide a comprehensive overview of the phytoremediation capabilities of transgenic alfalfa plants, presenting fundamental information for future research studies for enhancing phytoremediation efficiency.

Assessment of Pediatric Cancer and Its Relationship to Environmental Contaminants: An Ecological Study in Idaho.

The primary aim of this study was to determine the degree to which a multivariable principal component model based on several potentially carcinogenic metals and pesticides could explain the county‐level pediatric cancer rates across Idaho. We contend that human exposure to environmental contaminants is one of the reasons for increased pediatric cancer incidence in the United States. Although several studies have been conducted to determine the relationship between environmental contaminants and carcinogenesis among children, research gaps exist in developing a meaningful association between them. For this study, pediatric cancer data was provided by the Cancer Data Registry of Idaho, concentrations of metals and metalloids in groundwater were collected from the Idaho Department of Water Resources, and pesticide use data were collected from the United States Geological Survey. Most environmental variables were significantly intercorrelated at an adjusted P‐value <0.01 (97 out of 153 comparisons). Hence, a principal component analysis was employed to summarize those variables to a smaller number of components. An environmental burden index (EBI) was constructed using these principal components, which categorized the environmental burden profiles of counties into low, medium, and high. EBI was significantly associated with pediatric cancer incidence (P‐value <0.05). The rate ratio of high EBI profile to low EBI profile for pediatric cancer incidence was estimated as 1.196, with lower and upper confidence intervals of 1.061 and 1.348, respectively. A model was also developed in the study using EBI to estimate the county‐level pediatric cancer incidence in Idaho (Nash‐Sutcliffe Efficiency = 0.97).

Quantifying and characterising metal concentrations in Derwent Estuary sediments using portable X-ray fluorescence spectrometry

The Derwent Estuary is highly enriched in potentially toxic elements, such as Zn, Pb, Cu, As, Hg and Cd, owing to inputs from historical industrial activity adjacent to the river, predominantly prior to strict environmental protections introduced in the 1970s. Contaminants are now buried at shallow depths within the sediment profile, in one or two highly concentrated layers decreasing in concentration away from an electrolytic zinc refinery, regarded as the main source of the contaminants. Enriched metals (Zn, Pb, Cu, Cd and As) in the estuary were estimated from data collected from 37 sediment cores using a portable X-ray fluorescence spectrometer that was validated against inductively coupled plasma mass spectrometer analyses. The thickness of the metal and metalloid enriched layers ranges from 32.5 to 107.5 cm, with an average thickness of 63 cm. Sedimentation rates based on this layer and the time since the start of zinc processing are approximately 0.46 cm/year. Sedimentation rates based on the thickness since maximum metal and metalloid concentrations are between 0.17 and 1.64 cm/year. Based on these sedimentation rates, the average time it will take for surface sediments to return to background metal and metalloid concentrations, if left undisturbed, is approximately 123 years. KEY POINTS Metal contaminant concentrations in Derwent Estuary sediments have two clear peaks in concentrations at depth, where estuary sediments have been enriched at varying rates over the last 97 years. The contaminated layer varies in thickness throughout the estuary, but has an average thickness of 63 cm, a maximum thickness of 107.5 cm and a minimum thickness of 32.5 cm, from surface sediments to the bottom of contamination. All surface sediments were enriched in metals or metalloids, but the overall trend in metal concentrations is decreasing from a major enrichment peak to moderate concentrations at the sediment–water interface. The time required for surface sediments to return to acceptable concentrations as defined by the ISQG is estimated to be on average 123 ± 88 years for the whole estuary with different parts of the estuary returning to background at different times.

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.

Effects of living in industrial and vehicular traffic areas and increasing of carcinogenic and non-carcinogenic diseases in children

We investigated the 123 male children from Ahvaz, average age 7.56, and its relation with metalloids' levels in children's blood. In this study, seven metalloids (As, Cd, Cr, Co, Hg, Ni and Pb) in children blood were measured and calculated non-cancer and cancer risks due to metalloids exposure atmosphere regions including industrial (Padad), vehicle traffic (Golestan) and reference (Kianpars). The higher concentrations of metals in the Padad ambient air As, Cd, Co, Cr, Hg and Ni coincided with the higher concentrations of the same metals in exposed children (P < 0.05) versus the reference. Children in Golestan had the highest blood lead concentrations (P < 0.05). Non-cancer risk (HIinhal) of atmospheric metalloids in the Padad were 1.78 times (P < 0.001) and cancer risk (ILCRinhal) assigned to As, Co, Cd and Ni were 112.1, 1.66, 1.81 and 1.55 times, respectively higher than those of Kianpars. The spatial distribution of children's blood metalloids concentrations showed an abnormal increase of 12–35 ng/mL, 5–10 ng/mL, 15–35 ng/mL, 5–10.5 μg L−1, 1–3.5 μg L−1 and 12–40 ng/mL for BAs, BCd, BCo, BCr, BHg and BNi respectively in the industrial area which children in the industrial area are prone to chronic diseases.

Toxic elements and trace elements in Macrolepiota procera mushrooms from southern Spain and northern Morocco

Anthropogenic activities, such as mining and fossil fuel combustion, produce large amounts of pollutants that affect environmental homeostasis. Wild edible mushrooms fructify exposed to environmental conditions, proving to be efficient accumulators of trace elements and toxic and potentially toxic elements. Due to the increasing consumption of mushrooms worldwide, this is of public health concern. In this work, the total content of chromium (Cr), arsenic (As), cadmium (Cd), mercury (Hg), lead (Pb), copper (Cu), zinc (Zn), and selenium (Se) was determined by ICP-MS in the caps and stipes of the high valued wild edible mushroom Macrolepiota procera collected in several locations of the South of Spain and the North of Morocco. The results obtained have indicated that the cap of M. procera contains a broad spectrum of both toxic elements and trace elements, occurring in higher contents in this part of the fruiting body with respect to the stipe. Moreover, Cu was the predominant element found in the samples studied, followed by Zn in most of the cases. The one-way ANOVA/Kruskal-Wallis test indicated that there were no significant differences in metal and metalloid content between the geographical areas studied. In addition, the results obtained through Hierarchical Cluster Analysis (HCA) and Principal Component Analysis (PCA) support the conclusions drawn through univariate statistical studies, indicating that there is no obvious clustering trend for the M. procera cap samples based on the sampling area. The health risk assessment for M. procera caps showed a cause for concern related to Cr, Cd, As, and Hg due to frequent consumption of around 300 g of fresh caps per day during the mushrooming season.

The solid-state partitioning, distribution, and mineralogical associations of arsenic and antimony: Integrated findings from the Altiplano Puna, South America and international comparisons

Arsenic (As) and antimony (Sb) are potentially hazardous metalloids and their presence in the environment is often related to mineral deposits, mines, and thermal springs. Despite their similar chemical properties, the distribution and behavior of As and Sb in nature has been shown to differ. In order to contribute to a better understanding of As and Sb in the environment as well as the important parameters controlling their mobility, this study presents a synthesis of geochemical results in the Altiplano-Puna of Chile and Bolivian Sb belt. Analyses include (i) solid-state partitioning, (ii) mineralogical studies and (iii) concentrations of both metalloids in groundwater, surface water, porewater, and fluvial and lake sediments in distinct seasons. Consistencies were found between the mobilization patterns of As and Sb in the studied sites where As is generally more mobile than Sb; however, mining-affected areas in the Bolivian Sb belt tend to be associated with a higher proportion of mobile Sb. From a mineralogical standpoint, As is generally associated with iron oxides and hydroxides and As-bearing pyrites, while Sb is linked to iron oxides, hydroxides, and clay-sized phyllosilicates. When compared to different metallogenic settings outside the Altiplano-Puna plateau (the Loa River Basin of northern Chile and Xikuangshan Mine in China), the following conclusions are consistent with the results obtained from the Altiplano-Puna: dissolved Sb concentrations tend to decrease with distance from the respective mining facility, the mobility of Sb is typically lower than As, and the preferred mineralogical associations are iron oxides and hydroxides. Finally, based on the seasonal analysis of As and Sb, it is conceptualized that wetlands behave as a source of As and as a sink and source of Sb depending on the water column; in addition, consideration must be taken regarding aeolian weathering.

Variability of metal and metalloid content in sludge as affected by sources and seasons

Variability of metal and metalloid content in sludge as affected by sources and seasons

Assessing the level of contamination of metals in surface soils at thermal power area: Evidence from developing country (India)

The purpose of this study was to determine the concentrations and contamination level of heavy metals and metalloid (i.e., Zn, Fe, Cu, Mn, Pb and As) in sediment samples taken from a thermal power station's 5 km buffer area (Bandel thermal power station-BTPS) in West Bengal, India. The atomic absorption spectrophotometer (AAS) was used to determine the presence of heavy metals in soil samples. Heavy metal and metalloid concentrations such as Zn, Fe, Cu, Mn, Pb and As were studied using various contamination and pollution-related indexes such as geo-accumulation index, enrichment factor, contamination factor, contamination degree, modified degree of contamination index, and pollution load index, and spatial distribution was presented using interpolation technique. An ecological risk index for all metals and a forecasted ecological risk index are also used to investigate the impact of heavy metals on biological elements in the soil. ANOVA and the Kruskal-Wallis test were among the multivariate statistical procedures used. Hierarchical cluster analysis was used to estimate the spatial similarity of sample locations, and Pearson's correlation was used to determine the relationship between different metal concentrations and soil physico-chemical parameters. Almost all of the sample sites had soils of very good to medium quality, according to the study. All heavy metals at this research site, with the exception of arsenic and lead, behave as plant micronutrients. Furthermore, no heavy metal band, with the exception of As, had a consistent concentration. Almost all of the sampling locations had extremely low to very low levels of pollution. • The current study investigates the impact of a thermal power station on the soil quality in the surrounding area. • Geo-accumulation, enrichment factor, contamination factor, and pollution load index applied to illustrate soil contamination • The average soil quality rating implies that soil quality has degraded insignificantly across a radius of 0–2 km. • Almost every sampling point in the study area had pollution levels that were extremely low to low.

Assessment of the Ecotoxicity of Pollution by Potentially Toxic Elements by Biological Indicators of Haplic Chernozem of Southern Russia (Rostov region).

The content of various chemical elements such as metals, metalloids, and nonmetals in the environment is associated with natural and anthropogenic sources. It is necessary to normalize the content of metals, metalloids, and nonmetals as potentially toxic elements (PTE) in the Haplic Chernozem. The soils of the Southern Russia are of high quality and fertility. However, this type of soil, like Haplic Chernozem, is subject to contamination with a wide range of PTE. The aim of the work was to rank metals, metalloids, and nonmetals by ecotoxicity in Haplic Chernozem. To assess the ecotoxicity of chernozem, data for 15 years (2005–2020) were used. Biological indicators used to assess the ecotoxicity of Haplic Chernozem: catalase activity, cellulolytic activity, number of bacteria, Azotobacter spp. abundance, to change of length of radish’s roots. Based on these biological indicators, an integral indicator of the state of Haplic Chernozem was calculated. The ecotoxicity of 23 metals (Cd, Hg, Pb, Cr, Cu, Zn, Ni, Co, Mo, Mn, Ba, Sr, Sn, V, W, Ag, Bi, Ga, Nb, Sc, Tl, Y, Yb), 5 metalloids (B, As, Ge, Sb, Te) and 2 nonmetals (F, Se) as priority pollutants. It is proposed to distinguish three hazard classes of metals, metalloids, and nonmetals to Haplic Chernozem: I class — Te, Ag, Se, Cr, Bi, Ge, Sn, Tl, Hg, Yb, W, Cd; II class — As, Co, Sc, Sb, Cu, Ni, B, Nb, Pb, Ga; III class — Sr, Y, Mo, Zn, V, Ba, Mn, F. It is advisable to use the results of the study for predictive assessment of the impact of metals, metalloids, and nonmetals on the ecological state of the soil during pollution.

Биогеохимическая характеристика корнеобитаемого слоя травянистых растений на рекультивированных участках техногенных отходов

The introduction of the work substantiates the relevance of studying the biogeochemistry of the root layer of herbaceous plants growing on man-made waste from coal mining and iron ore enrichment after 40 years of reclamation. The main part of the report is devoted to the results of determining the gross content of heavy metals and metalloids, Sorg., residual toxicity, occurrence and growth characteristics of the bacterium Azotobacter chroococcum in embryos and background soil under similar plants. It is shown that during the long-term development of embryosems on waste of different origin, a high pool of heavy metals and metals is preserved in them, and Sorghum accumulates. In the area of coal mining around the roots of the clover, the maximum concentrations of Pb are detected, while cereals - Br. On the forested tails of the iron ore agglomeration, the trend is different: Ca, Ni, Cu, Mn, Zn are concentrated around the roots of cereals, and As is near the roots of the clover. However, the residual toxicity is manifested only on the tailings of the iron ore agglomeration. It has been established that the occurrence of azotobacter in the root layer of different plants is ubiquitous, but in the embryos of the forested tailings pond, the bacterial populations are heterogeneous, they contain donkey strains showing luminescence, rhizoid growth type and antagonism. Around the roots of the clover, conditions were formed that were less favorable for reproduction than under cereals. The data obtained expand knowledge about the role of phytobiomes in the migration of chemical elements at man-made facilities, can be taken into account when developing toxicity neutralization and in predicting the effectiveness of biological reclamation.

Guideline Values for the Content of Chemical Elements in Soils of Urban Functional Zones: A Review

—The Russian soil quality assessment system, where the guideline values for the content of heavy metals and metalloids derived for arable lands (mostly, in terms of the general sanitary indicator of harmfulness) are applied to soils of the residential area and the protected area of water supply sources, can be updated using international experience, e.g., substantiation of generic values for urban functional zones since, with a few exceptions, the Russian soil quality guidelines are the same for all soils of the country. In order to assess the applicability of foreign approaches to Russian realities, we have thoroughly analyzed the original and most developed legislation systems of the soil quality control in cities of Germany, Canada, and the United States, as well as the systems of Australia, New Zealand, Republic of South Africa, and the countries of the European Union, where the values are land use specific. In this paper, we summarize the principles of soil quality assessment for the contents of chemical elements, brief the methodology used in different countries and the consequences of exceeding the standards, and highlight some clues for improving the Russian soil quality assessment system. The Russian soil quality assessment system can be improved and updated by substantiating (i) the land use specific standards for cities with the focus on actual subjects of standardization (the health of ecosystems, children, or adults); (ii) the standards for different geochemical environments taking into account the specific features of migration of substances; and (iii) the standards for the soil materials used to construct lawns and roadside areas. In addition, we suggest (i) developing a comprehensive system of management decisions for the case when soil quality standards are exceeded; (ii) legitimizing the concept of historical pollution that existed before the commencement of business activities; and (iii) establishing the minimum volume of soil and the depth or set of soil horizons to be remediated or removed due to pollution.

High density metals and arsenic in algae of the White, Barents and Kara Seas

The analysis of the content of heavy metals (Cd, Cu, Mn, Pb, Zn) and metalloid As in the most common algae of the White Sea, as well as in algae found in the band of storm emissions at various points of the coast of the island Severny of the Novaya Zemlya archipelago, was carried out. The series of decreasing concentrations of the studied elements in the thalloms of phycobionts are constructed. It has been established that Zn is the dominant element in the algae of the White Sea. Mn prevails in the conditions of the Barents Sea. In the group of stable sequences, the position of As is very unstable, which can be explained by the different origin of the algae samples, the different ecological state of their original habitats, as well as the fact that the metalloid As in the algae is represented in anionic form.

A review of microplastic fibres: generation, transport, and vectors for metal(loid)s in terrestrial environments.

The laundering of synthetic fabrics has been identified as an important and diffuse source of microplastic (<5 mm) fibre contamination to wastewater systems. Home laundering can release up to 13 million fibres per kg of fabric, which end up in wastewater treatment plants. During treatment, 72-99% of microplastics are retained in the residual sewage sludge, which can contain upwards of 56 000 microplastics per kg. Sewage sludge is commonly disposed of by application to agricultural land as a soil amendment. In some European countries, application rates are up to 91%, representing an important pathway for microplastics to enter the terrestrial environment, which urgently requires quantification. Sewage sludge also often contains elevated concentrations of metals and metalloids, and some studies have quantified metal(loid) sorption onto various microplastics. The sorption of metals and metalloids is strongly influenced by the chemical properties of the sorbate, the solution chemistry, and the physicochemical properties of the microplastics themselves. Plastic-water partition coefficients for the sorption of cadmium, mercury and lead onto microplastics are up to 8, 32, and 217 mL g-1 respectively. Sorptive capacities of microplastics may increase over time, due to environmental degradation processes increasing the specific surface area and surface density of oxygen-containing functional groups. A range of metal(loid)s, including cadmium, chromium, and zinc, have been shown to readily desorb from microplastics under acidic conditions. Sorbed metal(loid)s may therefore become more bioavailable to soil organisms when the microplastics are ingested, due to the acidic gut conditions facilitating desorption. Polyester (polyethylene terephthalate) should be of particular focus for future research, as few quantitative sorption studies currently exist, it is potentially overlooked from density separation studies due to its high density, and it is by far the most widely used fibre in apparel textiles production.

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.

Infrared thermographic investigation of the oxidation behaviour of sulfide minerals from antimony-bearing rocks exemplified by the Podkozara deposit, Bosnia-Herzegovina

To date, prediction of the drainage chemistry of geologic materials at mine sites commonly relies upon well-established mineralogical and geochemical test work. Antimony (Sb) deposits require water quality risk assessments that consider the contaminant's solubility and mobility behaviour. To investigate the oxidation reaction of sulfides, a newly designed infrared (IR) thermographic test protocol was used to visualise oxidising sulfide minerals and to classify the rock types from the Podkozara Sb project, Bosnia-Herzegovina according to their oxidation reactivity. Furthermore, the sample materials were geochemically and mineralogically analysed using pXRF, powder XRD, ICP-AES, ICP-MS and NAGpH techniques. Four rock types have been recognised in the deposit: (i) stibnite mineralised quartz veins (SMQV); (ii) stibnite mineralised carbonate rocks (SMCR); (iii) pyritic phyllites; and (iv) mylonitic marbles. As indicated by the defined rock types, stibnite and pyrite are the only two sulfide minerals detected in the sample materials, causing reactions of varying intensities during IR testing. The intensity and duration of the oxidation reaction depends on various factors, including the sulfide mineral itself, the ore content and galvanic reactions between the sulfide minerals. Based on IR testing, it could be demonstrated that SMQV and SMCR are highly reactive and have a high risk for sulfide oxidation and associated Sb release into waters in any pH environment. Pyritic phyllites and tailings show less oxidation reaction intensities and no oxidation reactions could be recorded for marbles. Tailings pose a low risk and pyritic phyllites as well as marbles do not show a risk at all for Sb deportment. For pyritic phyllites, however, a release of Fe must be considered. In addition, underground mine and local surface waters were analysed for their pH, Eh as well as dissolved metal, metalloid and sulfate contents. The mine waters possess especially strongly elevated Sb values (5–244 μg/L) at neutral to alkaline pH values (7.0–8.1). Thus, in the Podkozara deposit, there is a general excess of neutralising carbonate minerals that result in adequate buffering of generated sulfuric acid, limiting mobility of base metal cations in solution but this supports the mobilisation of Sb into mine waters. In this study, complementary conventional mineralogical and geochemical testing as well as novel IR visualisation of possible sulfide oxidation have revealed useful information on the likelihood of different rock types causing metalliferous drainage issues. In particular, IR thermographic testing provides valuable insights on the presence of oxidising Sb- and Fe-sulfides in ores and wastes. This information can be used to prepare suitable mitigation strategies for Sb-rich neutral mine drainage waters and serves as a sample pre-selection for long-term environmental studies and tests. Furthermore, this analysis shows that different management and separate disposal plans will be needed for different lithological wastes.

Cement and oil refining industries as the predominant sources of trace metal pollution in the Red Sea: A systematic study of element concentrations in the Red Sea zooplankton

The Red Sea is exposed to metals from a large variety of natural and anthropogenic sources. In this study, we analyzed 19 common element concentrations in 14 Red Sea zooplankton samples using inductively coupled plasma-optical emission spectrometry (ICP-OES). The average metal or metalloid concentrations of the Red Sea zooplankton were: Ca > Sr > Fe > Al > Zn > As > Cu > Mn > Cr > Mo > Ni > Pb > Cd. The As, Ca, and Cu concentrations significantly increased with increasing latitude, while Cd concentrations decreased (p < 0.01). Our study indicated that anthropogenic activities (i.e., cement factories and oil refining industries) might be the predominant sources of significantly high Cr (1718 mg/kg), Fe (11,274 mg/kg), Mn (57.3 mg/kg), Mo (286 mg/kg), Ni (226 mg/kg), Pb (332 mg/kg), and Zn (17,046 mg/kg) concentrations that recorded in the Central to North Red Sea zooplankton.

Metal and metalloid pollution in shelf sediments from the Gulf of Cádiz (Southwest Spain): Long-lasting effects of a historical mining area

The Gulf of Cádiz is an area historically affected by acid mine drainage and also by the discharge of two important rivers, the Guadiana and the Guadalquivir. Metal and metalloid (As, Cd, Hg, Pb, Zn, Cu, Cr, Ni, Mn, Fe, Al and Li) concentrations were measured in 33 surface sediment samples, collected in the continental shelf, inside the Ría de Huelva and the Bay of Cádiz, to assess the metal pollution status of this area. Geographical distribution was identified for different groups of metals: Cu, Cd, Zn, Hg and As were mainly associated with discharges of the Tinto and Odiel rivers, which have been historically affected by mining, into the Ría de Huelva. Sediments inside this Ría presented the highest concentrations of the whole area for these metals, and enrichment factors revealed that Hg and Cu pollution spread up to 20 km away from the mouth of this Ría, into the continental shelf. On the contrary, the distribution of Ni, Cr and Mn did not show a clear gradient with distance from a pollution source, and was mainly explained by geochemical factors, such as their association with fine materials. The comparison of metal concentrations with sediment quality guidelines, predicts that adverse ecological effects due to the metal pollution may be occurring in a group of stations located in the northwest corner of the studied area. Local background levels for metals in the Gulf of Cádiz were proposed and the information obtained will be useful to identify those areas where sampling must be intensified in ongoing Marine Strategy Framework Directive (MSFD) monitoring programs. These results corroborate that metal pollution is still a serious problem in the Gulf of Cádiz.