Total Trace Element Concentrations Research Articles

Soil Contamination and Biomarkers in Ucides cordatus in Mangroves from Baía de Todos os Santos, Bahia, Brazil

The aim of the present study was to analyze the response to exposure to pollutants (trace elements and organic pollutants) using biomarkers (micronucleated cells and glutathione S-transferase and catalase activity) in uçá crab Ucides cordatus. The study was carried out at four sites: Cacha Prego (CP) and Ponta Grossa (PG), areas with low anthropic activity; and Ilha de Maré (IM) and Pitinga (PT), areas affected by industrial activity. At each site, soil and crab samples were collected to analyze the contents of potentially toxic elements (total concentration and chemical partitioning of trace elements), polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs). Both total concentrations and geochemical fractions of Cu, Zn, and Ni in soils were significantly higher in IM. Likewise, higher reactive Pb contents were observed in mangroves both in IM and in PG. Values above quality limits were observed for organic pollutants (PAHs) in soils from CP and PT, while PCB contents were below the maximum permissible levels. Metals in crabs also showed spatial variations, with higher Cu concentrations in all tissues in IM and PT and higher Ni concentrations in hepatopancreas in PT during the dry season. PAH values in crabs did not show spatial variations; however, crustaceans with contents above maximum limits in their muscle tissue were found in CP. Crabs from the Baia de Todos Santos showed different responses in biomarker expression, with higher enzymatic activity and greater numbers of micronucleated cells in crabs from IM, suggesting oxidative stress and genotoxicity in this mangrove forest.

Size-resolved distribution of trace elements in lysimeter soil solutions under contrasting long-term agricultural management to assess their bioavailability

The chemical species of trace elements (TEs) in agricultural soils is highly variable under diverse conditions, requiring tools with clear resolution and minimal disturbance for exploration. A novel surgical (316L) stainless steel (SS) lysimeter with a 5 μm pore size was developed to collect field soil solutions. The size-resolved distribution of TEs were characterized into total (nitric acid digestion), particulate (0.45–5 μm), dissolved (<0.45 μm), colloidal (1 kDa to 0.45 μm), and mainly ionic (<1 kDa) fractions in the lysimeter soil solutions. Total concentrations of TEs (dry weight basis) in acid digested Gray Luvisolic soils were analyzed. Most TEs in lysimeter soil solutions were present in particulate phases, relevant to their geochemical affinities and occurrences in soil minerals. Among dissolved fractions, As, Ba, Co, Li, Mn, Tl, and V existed as mainly ionic species in the soil solutions. Copper, Pb, Al, Th, and U showed variable associations with dissolved organic matter (DOM) and/or inorganic colloids among agricultural treatments. Inorganic NPKS or NKS fertilizer applications with lower pH (5.25–5.74) enhanced mobility and potential bioavailability of Ba, Co, Li, Mn, and Pb present in mainly ionic species, compared with other locations (pH 5.82–6.37). Manure application exhibited a dual effect, potentially increasing bioavailability for As, Tl, and V due to probably enhanced cation exchange capacity (CEC), while also facilitating specific adsorption of Cu and U on DOM, potentially reducing their bioavailability depending on DOM molecular weight. Colloidal and ionic Al and Th concentrations were higher in forest soils than agricultural soils, with extremely low potential bioavailability of Th attributed to strong precipitation with inorganic colloids and adsorption on DOM. The lysimeter sampling and size fractionation method provided a clear insight into agricultural effects on TE distributions and enhancing understanding of agricultural soil health in terms of TE bioavailability in situ.

Estimating the bioaccessibility of atmospheric trace elements within the Athabasca bituminous sands region using the acid soluble ash fraction of Sphagnum moss

Total concentrations of trace elements in Sphagnum moss increase in concentration with distance toward bitumen mines and upgraders, but their solubility in the ash fraction after leaching in nitric acid is variable.

Distribution and Speciation of Trace Elements in Soils of Four Land-Use Systems

Land use has a greater impact on trace element (TE) concentration present in soils. In mountainous regions of the western Himalayas, some dominating geogenic and human-dependent anthropogenic factors are involved in the spatial distribution of TEs in various land uses. Soil samples were collected from permafrost, pasture, forest, and agricultural land-use systems of Babusar Valley and Fairy Meadows in Diamer districts and the Rama region in Astore Districts in replications for investigation of three TEs, i.e., copper (Cu), zinc (Zn), and nickel (Ni). These samples were analyzed for exchangeable, adsorbed, organically bound, carbonate precipitated, and residual forms. Significant differences among these TEs were observed. Differences in the levels of TEs within soil samples were observed to be influenced by land usage patterns. The physicochemical properties of soil samples were also investigated. Additionally, the total metals (Ni, Zn, Cu) were extracted and their concentrations were measured in all samples. The concentration of soil TEs was observed in the following order: adsorbed &lt; organically bound &lt; exchangeable &lt; residual &lt; carbonate precipitated form across all the land uses. The results indicate that the contents of TEs (Ni, Zn, Cu) in agricultural soils were greater than in the permafrost pasture and forest soil samples. The total TE concentration varied as Zn &gt; Ni &gt; Cu irrespective of the area and land uses. We believe this work will open avenues for researchers to explore TEs in various regions of the world.

Essential role of multi-element data in interpreting elevated element concentrations in areas impacted by both natural and anthropogenic influences.

This article presents a detailed analysis of a dataset consisting of 27 elements found in soils, soil eluates, and vegetables from private gardens in a region with a long history of coal mining and burning. With coal being one of the world's most significant energy sources, and previous studies highlighting elevated element levels in vegetables from this region, the objective of this study was to identify the factors that impact soil geochemistry and metal(loid) uptake in plants. Total major and trace element concentrations were analyzed in soils, soil eluates and vegetables by high resolution inductively coupled plasma mass spectrometry. The vegetable samples included six species: fennel, garlic, lettuce, parsley, onion, and radicchio. Each plant was divided into roots, stems, leaves, and/or bulbs and analyzed separately. In addition, the soil pollution status, bioavailable fractions and transfer factors from soil and soil eluates to different plant parts were determined. The comprehensive dataset revealed that, apart from the substrate enriched with various elements (Al, As, Co, Cr, Mo, Ni, Pb, Sb, Sn, Ti, U, V, and Zn), other anthropogenic factors such as the legacy of coal mining and combustion activities, associated industries in the area, transport, and agricultural practices, also influence the elevated element concentrations (Cd, Cu, Fe, Mn, and Se) in locally grown vegetables. The transfer factors based on element concentrations in aqueous soil eluates and element bioavailable fractions confirmed to be an effective tool for evaluating metal uptake in plants, emphazising to some extent the effects of plant species and revealing unique patterns for each pollution source within its environmental context (e.g., Cd, Mo, S, and Se in this case). The study highlights the crucial importance of utilizing comprehensive datasets that encompass a multitude of factors when interpreting the impacts of element uptake in edible plants.

Benthic foraminifera as proxies for assessing the effects of a pier marina construction: A case study in the naturally stressed environment of the Saco da Ribeira (Flamengo Bay, SE Brazil)

Brazilian coastal areas have been exposed to various anthropic influences including physical alteration such as marina construction. To assess the impact of the pier marina construction in the Saco da Ribeira cove (Flamengo Bay, SE Brazil), sedimentological (grain size), geochemical (organic and trace elements) parameters and benthic foraminifera were analyzed on a 50-cm-long dated sediment core covering the last century. The multiproxy approach applied to a numerical hydrodynamic model shows that the circulation in the study area underwent an overall reduction (ca. 30 %) after the pier marina construction in the 1970s, promoting an increase of mud accumulation and higher concentrations of total organic carbon and trace elements (i.e., Enrichment Factor Cu from 0.80 to 1.4) as well as a shift in the benthic foraminiferal assemblages (i.e., foraminiferal density from 63 to 23.20 specimens per 10 cm3 and dominance from 0.13 to 0.73). On the basis of these integrated data, better environmental conditions occurred before the 1970s, then an overall increase in environmental stress took place after the pier's marina construction. Our results provide a baseline for future biomonitoring projects in a stressed region and exemplify the strong capability and reliability of benthic foraminifera as bioindicators of paleoenvironmental changes in coastal environments and for understanding how human pressure might induce such changes.

Impact of agrochemicals application on soil quality indicators and trace elements level of wetlands under different uses

An attempt to boost agricultural production has led to increased agrochemical usage. Continuous agrochemical usage for decades has brought changes to soil properties. The study assessed the impact of agrochemicals (fertilizers and pesticides) on wetland characteristics in Abeokuta, Nigeria. Five wetlands under maize, plantain, rice, vegetable productions, and control site were studied. Profiles were dug on each wetland, and soil samples were collected from pedogenic horizons and analysed using appropriate techniques. The morphological properties like colour, texture, structure, and consistency differ across the wetlands. The particle size fraction showed that the sand content was higher than silt and clay contents. Soil chemical indicators like pH, OM, TN, and K were lower in agrochemicals applied fields than in the control site, whereas available P was increased in these fields. The total trace element contents were highly affected and their levels have almost reached the permissible limit of WHO standards for agricultural purposes. Nutrient depletion and trace element build-up were more prominent in agrochemicals applied fields as against the control field. Information gathered from this study can help the policymakers on the proper usage and management of these wetlands on a productive and sustainable basis. To reduce agrochemicals impact which majorly contributed to the differences in the soil quality indicators and trace elements level, it is our opinion that planning to shift toward organic agriculture with no or minimal use of agrochemicals are to be considered.

Sulfide Trace Element Signatures and S- and Pb-Isotope Geochemistry of Porphyry Copper and Epithermal Gold-Base Metal Mineralization in the Elatsite–Chelopech Ore Field (Bulgaria)

The Elatsite–Chelopech ore field in the northern part of the Panagyurishte district in Central Bulgaria comprises numerous spatially associated porphyry copper and epithermal gold deposits and prospects. In addition to the mineralization and alteration features, trace elements, lead and sulfur isotope signatures of sulfide minerals from porphyry copper, base metal and gold-base metal deposits/prospects have been studied. LA-ICP-MS analyses of pyrite, arsenopyrite and sulfosalt minerals validate them as major carriers for Au, Ag, Sb, Se and Co. Pyrite from the three types of mineralization has specific geochemical characteristics. Pyrite from the porphyry copper deposits/prospects has generally lower total trace element content compared to pyrite from the epithermal prospects, except for Se, Co and Ni. Pyrite from the base metal and gold-base metal veins is enriched in As, Au, Ag, Sb and Pb. In pyrite from the base metal deposits, Co and Ni have contents comparable to the pyrite from the porphyry copper deposits, while pyrite from the gold-base metal veins shows lower Co and Ni. Arsenopyrite from these deposits shows similar features. Similarly, sphalerite from the gold-base metal veins also has lower Co content compared to sphalerite from the base metal veins but higher In and Cu contents. In addition to the close spatial relationships between the Elatsite and Gorna Kamenitsa porphyry Cu deposits and Negarstitsa-West and Dolna Kamenitsa base metal prospects, as well as similarities in the mineralization and alteration styles, the lead isotopic (206Pb/204Pb = 18.61–18.68, 207Pb/204Pb = 15.64–15.65 for porphyry and 206Pb/204Pb = 18.55–18.67, 207Pb/204Pb = 15.64–15.68 for base metal) and sulfur isotopic (δ34S values of −3 to +1‰ for porphyry and δ34S values of −1.7 to +3.5‰ for base metal) signatures of sulfides support the idea of a genetic link between these two types of deposits. The porphyry and base-metal mineralization result from a common major ore-forming event during the Late Cretaceous, corresponding to deep/higher-temperature and shallower/distal/lower-temperature environments, respectively. In particular, more radiogenic lead (206Pb/204Pb = 18.41–18.47, 207Pb/204Pb = 15.67–15.76) and slightly different sulfur isotopic compositions (δ34S values of +3.5 to +10.6‰) of sulfides from the distal gold-base metal veins of Kordunsko Dere, Svishti Plaz and Shipkite might be a consequence of the interaction of the ore-forming fluids with an external older crustal and isotopically positive S source. Alternatively, a different fluid source/event for the formation of these gold-base metal veins may be suggested.

Scheelite trace element compositions: A robust new tool for mineral exploration

Scheelite is a widespread accessory tungstate mineral that contains a variety of trace elements. Scheelites from the major types of magmatic-hydrothermal mineral deposits (86 deposits, including quartz-vein and greisen, porphyry, skarn and orogenic Au deposits) have been collected and analyzed using laser ablation-inductively coupled plasma mass spectrometry (3270 data, including 584 analyses). Discriminant analysis using Mo, Sr, Nb, La, Ce, Eu, Dy, Yb, Y, Ta, Pb, (Ce/Yb)N, (La/Sm)N, (Gd/Yb)N, Eu anomaly, Ce anomaly, (La/Yb)N, LREE/HREE, Y/Ho and Mo + Sr + Nd + rare-earth elements (REE) + Y + Ta + Pb reveals that scheelites from different mineral deposits can be distinguished. Scheelites from quartz-vein and greisen deposits have high total contents of trace elements that partition onto the Ca sites (Mo, Sr, Nd, REE, Y, Ta, Pb). Scheelites from the porphyry W ± Cu ± Mo deposits, which have been studied in this work, are characterized by low Mo and positive Eu than scheelites from porphyry Cu ± Mo deposits. This indicates that large scale tungsten deposits are related to reduced hydrothermal fluids, in contrast to the oxidized fluids associated with porphyry Cu ± Mo deposits. Scheelites from skarn W ± Sn ± Mo deposits typically exhibit a wide range of Y/Ho ratio and a higher sum of the elements Mo, Sr, Nd, REE, Y, Ta, and Pb compared to that from the skarn Cu ± Mo ± W deposits, indicating that increased amount of fluorine probably leads to large-scale W, Mo, and Sn mineralization during magmatic-hydrothermal processes. Scheelites from the greisen W-Sn polymetallic deposits tend to have more restricted Sr compositions and Eu anomalies than those from the quartz vein W-Sn deposits, as well as relatively high Gd, Tb, Dy and Ho contents, which coincide with extensive hydrothermal alteration, indicating intense fluid-rock interaction during mineralization. Using Discriminant projection analysis (DPA), scheelites from many ore deposits can be readily separated from each other. This study demonstrates that heavy-mineral scheelite grains collected during regional geochemical surveys are effective in identifying specific types of buried mineral deposits in potential mineralization area. Scheelite geochemistry with DPA provides an effective guidance for mineral exploration.

Soil Contaminated with Hazardous Waste Materials at Rio Tinto Mine (Spain) Is a Persistent Secondary Source of Acid and Heavy Metals to the Environment

Mineralogical analysis and laboratory-based leaching tests coupled with speciation modeling were undertaken to quantify the potential for short-term acid generation and the release of trace elements from soils heavily contaminated with mine waste at Rio Tinto. Three different waste materials were considered as case studies: roasted pyrite, copper slags, and leached sulfide ores. The results showed elevated values of net acid generation (up to 663 mmol H+/kg), the major pools being potential sulfidic acidity and acidity retained in jarosite. Remarkable contents of As and toxic heavy metals were found especially in the slag-contaminated soil. Copper, Zn, and Pb were the most abundant metals in the acid leach solutions resulting from mine soil-water interaction, with peak values of 55.6 mg L−1, 2.77 mg L−1, and 2.62 mg L−1, respectively. Despite the high total contents of trace elements occurring in soil, the mobile fraction was limited to maximum release values of 12.60% for Cd and 10.27% for Cu, according to the test leaching. Speciation calculations indicated that free metal ions (M2+) and sulfate species (MSO40) accounted for most of the dissolved load. Acid soil drainage is a secondary source of acid and heavy metals in the mine site and, therefore, an effective land reclamation program should ensure that acidity and metal mobility are reduced to environmentally sustainable levels.

Characterization of the short-term temporal variability of road dust chemical mixtures and meteorological profiles in a near-road urban site in British Columbia

ABSTRACT Springtime road dust is a common air quality concern for northern latitudes communities. Traction material, brake wear, tire wear, and other particles entrained in snow during winter become re-suspended into the air as the snow melts. Characterization of within-season variability of road dust composition and weather conditions is critical to understanding its acute health impacts. Sixty 24-hour samples of PM10 were collected with a high-volume sampler at a near-road site in Prince George, British Columbia. Near-road samples were collected intermittently in winter and daily in spring. All samples were analyzed for 18 trace elements. We used data from a nearby regulatory monitor to estimate daily coarse fraction (PM10–2.5). Proportion of PM10–2.5 in PM10 was used to classify days as high or low road dust based on a threshold of 65% PM10–2.5. We identified clusters of near-road samples based on weather parameters and PM10 components using Bayesian profile regression (BPR). Twenty-one near-road PM10 samples were classified as high road dust days and 34 as low road dust days. Concentrations of total trace elements and specific trace elements were significantly higher on high road dust days (aluminum, chromium, iron, lead, tin, vanadium, and zinc). High road dust days also had low relative humidity and precipitation and higher temperature and air pressure. We identified five clusters of near-road PM10 mixtures that suggested an interaction between temperature and humidity for road dust impacts. Samples from a near-road site indicated days highly affected by springtime road dust are distinct from other days based on particulate mixtures and meteorological factors. Higher loading of trace element mixtures in PM10 on high road dust days has important implications for acute toxicity of road dust. Relationships between road dust and weather may facilitate further research into health effects of road dust as the climate changes. Implications: Non-tailpipe emissions driven by springtime road dust in northern latitude communities is increasing in importance for air pollution control and improving our understanding of the health effects of chemical mixtures from particulate matter exposure. High-volume samples from a near-road site indicated that days affected by springtime road dust are substantively different from other days with respect to particulate matter mixture composition and meteorological drivers. The high load of trace elements in PM10 on high road dust days has important implications for the acute toxicity of inhaled air and subsequent health effects. The complex relationships between road dust and weather identified in this study may facilitate further research on the health effects of chemical mixtures related to road dust while also highlighting potential changes in this unique form of air pollution as the climate changes.

Physico-chemical properties and transboundary transport of PM2.5 in Bien Hoa City, Dong Nai Province, Southeastern Vietnam.

Air pollution is one of the most concerning environmental issues, wherein PM2.5 concentration plays an important role. This study monitored and evaluated the PM2.5 concentration trends in Bien Hoa City, Dong Nai Province, Vietnam. Twenty 24-h PM2.5 samples were continuously collected during the rainy (15 Oct. to 25 Oct. 2021) and dry (19 Mar. to 29 Mar. 2022) seasons. The PM2.5 samples were analyzed by scanning electron microscopy to determine the surface pattern and size distributions were analyzed using ImageJ software. The water-soluble fractions of 15 trace metal(oid)s concentrations (Al, Cu, Ni, K, Ca, Co, Mn, Cr, As, Zn, Pb, Cd, Na, Fe, and Mg) bound to PM2.5 were analyzed by inductively coupled plasma-mass spectrometry. The results showed that the 24-h fine fraction PM2.5 concentrations were 24.1 ± 12.2μg/m3 and 63.0 ± 18.7μg/m3 in the rainy and dry seasons, respectively. The results indicate that the size distributions of the particles of 2.0-2.5μm are minor, and the majority are ultrafine particles with aerodynamic diameter ≤ 1.0μm. Overall, the mass concentration level of the water-soluble fraction of trace metal(oid)s in PM2.5 in the rainy season was higher than that in the dry season. Among these, Ca, K, and Na were the most abundant earth crustal elements in PM2.5 in the rainy and dry seasons, accounting for 85% and 41.2% of the total trace element concentrations, respectively. The major sources of PM2.5 are local and regional sources of thermal power plants, industrial parks, and waterborne transportation (domestic rivers and marine). The activities undertaken to remove Agent Orange (e.g., soil excavation, transportation, and rotary kiln incinerators) at the Bien Hoa airbase area also cause increases in the PM2.5 level in the atmosphere of Bien Hoa City.

Sequential chemical extraction of copper from clay: an overview

In general, the total content of heavy metals and trace elements in soils is useful, but the speciation (bioavailability) is also in need for agricultural purpose, for example. The present paper studies the efficiency of some soil remediation treatments on soils polluted, especially with copper, by using sequential chemical extraction (SCE). Usually, SCE is fractioned, according to Tessier, in five fractions: exchangeable, carbonate bound, Fe and Mn oxide bound, organic matter bound and residual. Copper (Cu) is one of the contaminants found in many soils around the world. In small concentration, it is an essential microelement for plants and organisms, but in high concentrations, it is harmful for the entire ecosystem. Because the concentrations of Cu are associated with soil texture and several other parameters, many remediation soil treatments are based on organic mixture, by converting the element into a less exchangeable form, and thus less bioavailable. In this study, the efficiency of organic amendments such as organic matter (OM), zero-valent iron with organic matter (OMZ), dolomite (DL) and organic matter with dolomite (OMDL) are investigated. These treatments were applied on soils affected by Cu pollution. The results indicated that OMDL and OMZ treatments had the best efficiency on Cu pollution, by enhancing the stability of the element, decreasing the level of bioavailability.

Composition of Three Common Chinese Herbal Medicines and the Influence of Preparation Types on the Bioaccessibility of Trace Elements.

The high concentration of trace elements in Chinese herbal medicine (CHM) is an important research topic for quality control. This study investigated the total concentration of trace elements in three herbs used as both medicine and supplementary food, including Astragalus membranaceus, Glycyrrhiza, and Isatidis. Further, the effects of different preparation ways, such as decoct, granule, and oral liquid, on the bioaccessibility of trace elements in CHM were disclosed. Results indicated that the total concentrations of trace elements in these three herbs were lower than the medical standards, but the concentrations of As and Pb in CHMs were higher than the standards for supplementary food. Different preparations ways affect bioaccessibility. Powder and oral liquid show a high bioaccessibility possibly because of the grinding process and the repeated extraction with ethanol. Among the three different CHMs, Isatidis showed higher bioaccessibility of As, which may be related to the sulfur fumigation process of this CHM. The three investigated CHMs were found to be safe as medicine but presented risks as supplementary food. The apparent influence of preparation procedures on the bioaccessibility of trace elements indicated that it is necessary to appropriately regulate preparation processes for CHMs.

Recycling of bottom sediment to agriculture: effects on plant growth and soil properties

PurposeThe use of bottom sediments in agriculture reduces the storage of excavated material and allows the nutrients it contains to be applied for soil fertilisation and improvement. However, the direct application of sediments to soil may cause numerous problems. Therefore, the addition of other waste materials may be a promising and useful method in the production of bottom-sediment-based growing media. The aim of the study was to evaluate the effect of growing media prepared on the basis of bottom sediments and various waste materials on the properties of soil as well as on the yield and chemical composition of courgette biomass.MethodsThe growing media were prepared with substrates in the form of mixtures with bottom sediments taken from the Rożnów reservoir. The effect of mixtures on plant growth was determined in a laboratory pot experiment. Air-dry mixtures (M1—bottom sediment with water treatment sludge (BS + SW); M2—bottom sediment with biomass ash (BS + BA); M3—bottom sediment with coffee hulls (BS + CH)) were mixed with soil (S) in the following proportions: combination I—25%, combination II—50%, combination III—75%, and combination IV—100% mixture.ResultsThe media did not have harmful effects on the plant or the soil environment. They had deacidifying properties; high contents of calcium, magnesium, potassium, and phosphorus; low total trace element content; and posed little risk of metal mobility. Heterocypris incongruens was the organism most sensitive to the substances contained in the studied media. The use of bottom-sediment-based media reduced the biomass of the test plant and, at the same time, limited the accumulation of trace elements in its aboveground parts.ConclusionMost of the analysed media were low-toxic to the test organisms and can potentially be used in agriculture, horticulture, or the reclamation of degraded land.

Measurement report: Size-resolved chemical characterisation of aerosols in low-income urban settlements in South Africa

Abstract. Naturally and anthropogenically emitted aerosols, which are determined by their physical and chemical properties, have an impact on both air quality and the radiative properties of the earth. An important source of atmospheric particulate matter (PM) in South Africa is household combustion for space heating and cooking, which predominantly occurs in low-income urban settlements. The aim of this study was to conduct a detailed size-resolved assessment of chemical characteristics of aerosols associated with household combustion through the collection of particulates in low-income urban settlements in South Africa to quantify the extent of the impacts of atmospheric pollution. Outdoor (ambient) and indoor aerosols in different size fractions were collected during summer and winter in four low-income urban settlements located in the north-eastern interior on the South African Highveld, i.e. Kwadela, Kwazamokuhle, Zamdela, and Jouberton. Mass concentration and chemical composition was determined for three size fractions, namely, PM1, PM2.5, and PM2.5−10. The highest concentrations of particulates were measured indoors with the highest mass concentration determined in the indoor PM2.5−10 (coarse) size fraction. However, the highest mass concentrations were determined in PM1 in all outdoor aerosol samples collected during winter and summer, and in indoor samples collected during summer. Significantly higher concentrations were determined for SO4-2 in outdoor and indoor particulates compared to other ionic species, with NH4+ and NO3- being the second most abundant. SO4-2 and NH4+ almost exclusively occurred in the PM1 size fraction, while NO3- was the major constituent in the larger size fractions. The highest SO4-2 levels were recorded for the winter and summer outdoor campaigns conducted at Zamdela, while NO3- and NH4+ concentrations were higher during the winter outdoor campaign. The combined concentrations of trace elements were higher for indoor particulates compared to outdoor aerosols, while the total trace element concentrations in PM1 were substantially higher than levels thereof in the two larger size fractions of particulates collected during all sampling campaigns. No distinct seasonal trend was observed for the concentrations of trace elements. Na, Ca, and Cr had the highest concentrations in particulates collected during outdoor and indoor sampling campaigns. Ni concentrations in outdoor and indoor aerosols exceeded the annual average European standard. PM1 collected during all sampling campaigns in low-income urban settlements had the highest organic carbon (OC) and elemental carbon (EC) concentrations. The highest OC and EC levels were determined in PM1 collected during the winter indoor campaign. OC and EC concentrations were highest during winter, which can be attributed to changes in meteorological patterns and increased household combustion during winter. Low OC/EC ratios determined for particulates collected in low-income urban settlements are indicative of OC and EC being mainly associated with local sources of these species. OC concentrations determined in this study were an order of magnitude lower than OC concentrations determined for ambient aerosols collected in the north-eastern interior of South Africa, while similar EC levels were measured. According to estimated dust concentrations, it was indicated that dust is the major constituent in all size ranges of particulates collected in this study, while trace elements were the second most abundant. However, trace elements made the highest contribution to indoor PM1 and PM1−2.5 mass. Mass concentrations and chemical concentrations determined for aerosols collected in low-income settlements reflect the regional impacts of anthropogenic sources in the north-eastern interior of South Africa and the influence of local sources.

Assessment of the phytoremediation effectiveness in the restoration of uranium mine tailings

Uranium (U) contamination due to mining and metallurgical operations is a serious problem and poses a high potential threat to humans and other organisms. The application of amendments and/or plants, known as assisted phytoremediation, can accelerate the adsorption, complexation and precipitation processes in soil, and therefore can facilitate the restoration of U mining areas. This study located in the central-west of peninsular Spain was focussed on two different U mine waste dumps (MWD), where the assisted phytoremediation process was implemented. At each MWD, an area of 10 ha (approx.) was selected for sugar lime (SL) application, at a rate of 75 T ha −1. In addition, after SL addition, common grasses Cynodon dactylon, Secale cereale, and the leguminosae Vicia sativa were seeded. Evolution of soil physico-chemical properties and plant development was monitored for 69 months in Top, Medium and Low areas of both MWDs. The main results indicated a positive effect of the amendment, improving the development of the spontaneous and induced vegetation and the accumulation of soil organic matter. Values of pH were maintained in the range of the neutrality during all the experimentation period. In general, total concentrations of trace elements (including U) presented a high variability. Values were similar in the different studied areas of each MWD (Top, Medium and Low) and did not change in time. Trace elements contents were, in general, higher than those found in non-contaminated soils. However, U and Mn availability decreased with time, as well as the accumulation of trace elements (especially U and Mn) in the studied plants. Moreover, these contents were lower than the permitted limit for animal consumption. In conclusion, application of phytoremediation contributed to the stabilization of U within the soil-plant system, mainly by its positive effects on vegetation cover and the consequent increase in soil organic matter.

Impact of Car Traffic on Metal Accumulation in Soils and Plants Growing Close to a Motorway (Eastern Slovakia).

The paper evaluates the impact of car transport on the distribution and accumulation of Zn, Cu, Pb and Cd in soils, as well as in the vegetation near a newly built R4 motorway Košice-Milhosť (Slovakia). Samples were taken from surface humus layer (litter) and 0–5, 10–20 and 20–30 cm mineral layers of Cambisol and Luvisol, as well as from assimilatory organs of Fraxinus excelsior, Quercus cerris, Quercus rubra, Negundo aceroides and Anthriscus sylvestris growing in the segments of geobiocoenosis Querci-Fageta Typica. The concentrations of total Zn and Cu were determined using SensAA AAS and the total concentrations of Cd and Pb using an instrument iCE 3000 Series AAS-F. Contamination factor (CF) values showed that surface humus layer of both soil units is moderately contaminated with Zn (1 ≤ CF ˂ 3), low contaminated with Cu (CF ˂ 1) and considerably contaminated with Pb and Cd (3 ≤ CF ˂ 6). Contamination of the surface humus layer of Luvisol with Pb is very high (CF > 6), while in the case of mineral layers with Zn and Cu it is low (CF ˂ 1). The mineral layers of Luvisol are moderately contaminated with Pb and Cd (1 ≤ CF ˂ 3) and Cambisol layers with Zn, Cu, Pb and Cd. For the group of 5 tested plants, higher values of toxic elements in the leaves were observed on Luvisol compared to Cambisol. However, only Cu conconcentrations in Luvisol significantly correlated with Cu concentrations in plants (r > 0.4 or r < 0.6). The same can be said for Zn concentrations in Cambisol (r > 0.8). The best indicator of the environment polluted by car traffic appears to be A. sylvestris. Transfer coefficients (TC ˃ 1) revealed that this species concentrated the most Zn and Cu on Luvisol and close to 1 are also the TC values found for Cu in F. excelsior and Q. cerris leaves taken on Luvisol. Lead is accumulated most efficiently in N. aceroides leaves and Cd in A. sylvestris leaves regardless of soil unit. Compared to background values, the total concentrations of trace elements in soils and plants were significantly higher and point to the pollution of forest ecosystems already in the initial stage of motorway operation.

Accumulation potential of heavy metals at different growth stages of Pacific white leg shrimp, Penaeus vannamei farmed along the Southeast coast of Peninsular India: A report on ecotoxicology and human health risk assessment

This study compared the heavy metal concentration in water, sediment, and shrimp at different growth stages of culture and subsequently evaluated the ecotoxicological and human health risk status. Total trace element concentration in the water, sediment and shrimp ranged from not detected (ND) (Hg) to 91.05 (Fe) μg/L, 0.01 (Hg) to 19, 246.33 (Fe) mg/kg, and ND (Hg) to 13.98 (Fe) mg/kg, respectively. Toxic metals such as, Cd, Hg, and Pb in shrimps ranged from ND to 2.11 mg/kg, ND to 0.158 mg/kg, ND to 0.088 mg/kg, and ND to 0.469 mg/kg, respectively. Toxic heavy metals at all the growth stages of shrimps (days of culture (DOC)-01 to DOC-90) were found below the maximum residual limit (MRL) of 0.5 mg/kg set by the European Commission (EC). Similarly, Cu, Zn, and As concentrations in shrimp were also far below the MRLs of 30 mg/kg, 100 mg/kg, and 76 mg/kg set by the World Health Organization and Food Safety and Standard Authority of India, respectively. The concentration of heavy metals increased from DOC-01 to DOC-90 and was positively correlated with the length and weight of the shrimps (p < 0.05). The risk assessment was estimated for both Indians and Americans and found no carcinogenic (lifetime cancer risk (LCR) < 10−4) and non-carcinogenic (THQ and TTHQ<1) health risks through consumption of shrimp cultured in this region. The hazard quotient (HQdermal < 1), hazard index (HI < 1), and LCR (<10−4) values of the heavy metals indicated that the dermal absorption might not be a concern for the local fishermen and marine fish/shrimp farmworkers. Water and sediment quality indices were applied to assess the surface water and sediment quality, and their results were found nil to low levels of heavy metal contamination at all the sampling sites. All heavy metals studied in sediments were < effect range low (ERL) and < threshold effect level (TEL), indicating no adverse biological effects on aquatic organisms. Therefore, regular monitoring of the shrimp aquaculture system throughout the crop will provide evidence of heavy metals bioaccumulation in shrimps. This research will provide baseline data to help farmers establish the optimal aquaculture practices and regulatory authorities to formulate legislation and strategies to reduce heavy metal biomagnification in shrimps from farm to fork.

Occurrence and human health risk assessment of mineral elements and pesticides residues in bee pollen

Bee pollen contains a diversity of bioactive components. Nevertheless, since pollen is retrieved from a variety of plants, including the cultivated ones which are subjected to agrochemical treatments, its contamination is unavoidable. In this context, 45 samples of pollen were analysed with optimized analytical methods for trace and macro elements (ICP-MS), pesticides and metabolites residues (LC & GC-MS/MS) content. According to the results, potassium and iron were the most abundant in terms of concentration and frequency of detection, while the contribution of the most hazardous elements, such as lead, arsenic, cadmium and mercury, to the total concentration of trace elements was lower than 1%. For pesticides, coumaphos was the most frequently detected in the examined samples (22%), followed by propargite, azoxystrobin, dimethoate and cypermethrin. Non-carcinogenic health risk assessment demonstrated in the majority of cases negligible risk for adults and children. On the contrary, carcinogenic risk assessment considering a worst case scenario disclosed nickel and in less extent chromium and arsenic, as risk drivers, exhibiting in several samples carcinogenic risk values for adults above the safety threshold. Yet, regarding that both adults and children unlikely will daily consume such pollen quantities, especially on a long-term basis, an overestimation of risk should be appraised.