Toxic Trace Metals Research Articles

Accumulation and partitioning of toxic trace metal(loid)s in phytoliths of wheat grown in a multi-element contaminated soil

Cropland contamination by toxic trace metal (loid)s (TTMs) has attracted increasing attention due to the serious consequential threat to crop quality and human health. Mitigation of plant TTM stress by silica amendment has been proposed recently. However, the relationship between the siliceous structure of phytoliths and TTMs in plants, and the environmental implications of phytolith-occluded trace metal (loid)s (PhytTMs) remain unclear. This study assessed the accumulation of five metal (loid)s, including lead (Pb), zinc (Zn), cadmium (Cd), copper (Cu) and arsenic (As), in the organic tissues and phytoliths of wheat grown in a mixed-TTM contaminated soil under both lightly and heavily contaminated conditions. The results show that the concentrations of plant TTMs and PhytTMs were significantly (p < 0.05) positively correlated, and higher in heavily contaminated wheats than those in lightly contaminated ones. The bio-enrichment factors between phytoliths and organic tissues were higher for As (1.83), Pb (0.27) and Zn (0.30) than for Cd (0.03) and Cu (0.14), implying that As, Pb and Zn were more readily co-precipitated with silicon (Si) in phytolith structures than Cd and Cu. Network analysis of the relationship between soil and plant elements with PhytTMs showed that severe contamination could impact the homeostasis of elements in plants by altering the translocation of TTMs between soils, plants, and phytoliths. The accumulation of TTMs in phytoliths was affected by the capacity of Si deposition in tissues and chelation of TTMs with silica, which could impact the role of PhytTMs in global biogeochemical TTM cycles.

Bioelectrocatalytic Reduction of Tellurium Oxyanions toward Their Cathodic Recovery: Concentration Dependence and Anodic Electrogenic Activity

Regulation on the usage of trace toxic metals and their depletion necessitates their detoxification/recovery. Tellurium scarcity in the environmental matrix and its multitude applications depicts its worth for recovery from toxic ionic forms. Bioelectrochemical systems (BESs) facilitate metal detoxification/recovery. In this study, a novel double-chambered BES coupled with a biotic anode and abiotic cathode was operated using varied concentrations of toxic tellurite oxyanions (Te4+) as a terminal cathodic electron acceptor (CEA), facilitating bioelectroreduction of Te4+ to elemental tellurium (Te0) (cathode) and wastewater treatment (anode). Results depicted a Te0 element recovery of 45.3% with a tellurite removal of 54.7% in the abiotic cathode with a simultaneous substrate degradation of 67% in the biotic anode. The cathodic Te0 recovery with increased CEA-dependent electrotrophy has proportionally influenced the anodic microbial enzymatic activity. Bioelectrochemical characterization showed an increased anodic electrogenic performance relative to the increased CEA concentrations, achieving a comparatively higher power density of 0.044 W/m2 in the Te-C condition. Recovered Te0 samples were analytically characterized for structural/compositional functionalities and speciation variations to confirm the presence of Te0 element and its crystalline nature at the cathode. The study provided the application feasibility of BESs in favoring Te detoxification/recovery at the abiotic cathode, while regulating the anodic microbial electron/enzymatic/metabolic flux.

Characterizing copper and zinc content in forested wetland soils of North Carolina, USA

Wetlands are often located in landscape positions where they receive runoff or floodwaters, which may contain toxic trace metals and other pollutants from anthropogenic sources. Over time, this can lead to the accumulation of potentially harmful levels of metals in wetlands soils. To assess the potential risk of Cu and Zn buildup in wetland soils in North Carolina, soil data from 88 wetlands were analyzed. In a subset of 16 wetlands, more intensive sampling was conducted. Samples were analyzed for Mehlich 3 Cu and Zn, and a subset of the samples was analyzed for total Cu and Zn. Overall, Mehlich 3 Cu and Zn were low, with mean values of 0.9mg/kg for Cu and 3.2mg/kg for Zn. Warning levels for Mehlich 3 Zn were only exceeded in three of the 88 sites; elevated Mehlich Cu was not observed. Total Cu and Zn were also low, with only a few sites having elevated levels; however, there was not a strong linear relationship between Mehlich 3 and total metals. Mean levels of Mehlich 3 Cu and Zn in wetlands were much lower than for human-impacted upland soils and background threshold concentrations that might be indicative of disturbance were much lower than warning levels for agricultural soils. The very low mobile Zn and Cu in most of these wetlands indicated that these metals do not pose a risk to the biota in most North Carolina wetlands, but wetlands with a direct and significant anthropogenic source of metal contamination could be exceptions.

Single toxicity of arsenic and combined trace metal exposure to a microalga of ecological and commercial interest: Diacronema lutheri

Eco-toxicological assays with species of economic interest such as Diacronema lutheri are essential for industries that produce aquaculture feed, natural food additives and also in drug developing industries. Our study involved the exposure of a single and combined toxicity of arsenic (As V) to D. lutheri for the entire algal growth phase and highlighted that a combined exposure of As V with other essential (Copper, Cu; Nickel, Ni) and non-essential (Cadmium, Cd; Lead, Pb) trace metals reduced significantly the cell number, chlorophyll a content, and also significantly increased the de-epoxidation ratio (DR) as a stress response when compared to the single toxicity of As V. Arsenic, as one of the ubiquitous trace metal and an active industrial effluent is reported to have an increased bio-concentration factor when in mixture with other trace metals in this study. In the combined exposure, the concentration of total As bio-accumulated by D. lutheri was higher than in the single exposure. Hence, polluted areas with the prevalence of multiple contaminants along with the highly toxic trace metals like As can impose a greater risk to the exposed organisms that may get further bio-magnified in the food chain. Our study highlights the consequences and the response of D. lutheri in terms of contamination from single and multiple trace metals in order to obtain a safer biomass production for the growing need of natural derivatives.

Evaluating the Accumulation of Antioxidant and Macro- and Trace Elements in Vaccinium myrtillus L.

This study was conducted in order to characterise the accumulation ability of Vaccinium myrtillus L for trace elements such as Al, Cd, Cu, Fe, Mn, Pb and Zn and selected macroelements Ca, K, Mg, Na and P. The accumulation of nutrient elements and trace elements (ANE and ATE) and changes in the ecophysiological responses in bilberry in differently polluted areas were compared. The accumulation of the elements in the roots, stems and leaves of bilberry from four sites (in the nearest vicinity of a zinc smelter, a Mining and Metallurgical Plant, a main road with a high traffic volume and an unprotected natural forest community) were measured using optical emission spectrometry with excitation using inductively coupled argon plasma after wet acid digestion. The highest Cd, Cu, Pb and Zn concentrations were found in the V. myrtillus samples that were growing under the influence of the emissions from the zinc smelter. Moreover, the level of the total accumulated trace metals (ATE—17.09 mmolc kg−1) was also highest for the bilberry at this site. However, in the same area, the sum of the accumulated macronutrients (ANE—296.92 mmolc kg−1) was lower than at the other sampling sites. An EF > 2 was found for Cd, Pb, Zn and Mn, which suggests that bilberries may be enriched in these metals. According to the translocation factor, V. myrtillus was an accumulator of Cd, Zn and Mn. An analysis of the ecophysiological responses showed that the greatest concentration of ascorbic acid was found in the leaves of V. myrtillus at the most contaminated site (3.32 mg g−1 fresh weight). There were no significant differences in the total phenols between the contaminated and non-contaminated sites. However, the lowest value of the total phenolic content (490.77 mg g−1 dry weight) was recorded at the site where the highest Fe concentration was detected in the leaves. A significantly positive correlation between the Cd, Pb and Zn concentrations and a strong negative correlation between the Mn concentration and ascorbic acid content in the leaves of bilberry was also observed. The results provide evidence that the ANE method, which is used to interpret the chemical composition of bilberry has made determining the impact of toxic trace metals on the mineral composition of V. myrtillus significantly easier and also that a non-enzymatic antioxidant such as ascorbic acid can be a good biomarker for determining the oxidative stress that is caused by toxic trace metals.

Enhancing the rheology and leachability of fly ash slurry using natural – synthetic mixed surfactant systemfor hydraulic stowing in underground mines

ABSTRACT The present investigation is intended to develop the stabilization and transportation behavior of fly ash slurry (FAS) using the mixture of the surfactants, namely, Sapindus laurifolia (S. laurifolia, natural) and sodium dodecyl sulfate (SDS, synthetic). In addition to the rheological study, an attempt has been made to remove the toxic and other trace metals through the leaching method to address the safe disposal of FAS for mining backfilling applications. The data obtained from the different rheological studies of ash concentrations in the range of 45–65.8% were fitted to the Bingham plastic model. Addition of synthetic surfactant SDS to natural surfactant S. Laurifolia does enhance the wettability of fly ash (FA) particles by decreasing the surface tension and increasing the zeta potential of the slurry. The effect of other parameters like temperature, mixed surfactant concentration, and FA concentration on the formulation, stability, and leachability of FAS was investigated and reported. The results from the present investigation revealed that the optimum dosages of surfactants for both leaching and transportation of FAS is 0.009 g/cc of saponin and 0.008 g/cc of SDS. The stabilization interaction and leaching mechanism were proposed considering the hydrophobic/hydrophilic property of FA, S. laurifolia, and SDS. Abbreviations CMC: Critical micellar concentration; S. laurifolia: Sapindus laurifolia; SDS: Sodium dodecyl sulfate; FA: Fly ash; FAS: Fly ash slurry; η: Dynamic viscosity; τ0: Yield stress; γ: Applied shear rate; ζ: Zeta potential; τ: Shear stress

Ecological risk assessment of trace metals in sediment from the Old Brahmaputra River in Bangladesh

ABSTRACT The assessment of trace metal contamination in river sediments is crucial for suggesting effective strategies to protect aquatic ecosystem health. In this study, six toxic trace metals (As, Cd, Cr, Hg, Ni and Pb) in the surface sediments from the Old Brahmaputra River in Bangladesh were examined to evaluate the potential ecological risks. Sediment samples were collected in September 2018 and analysed by an atomic absorption spectrometer. Mean concentrations (mg/kg dw) of trace metals were in the order of Ni (43.49) > Cr (30.25) > Pb (14.29) > As (3.74) > Hg (0.16) > Cd (0.03). Spatially the sedimentary metals did not vary significantly. Source analyses revealed anthropogenic origin for most of the metals. The contamination factor, enrichment factor and geoaccumulation index (I geo) revealed a low degree of contamination for all cases except Hg, which showed a moderate degree of contamination. According to the sediment quality guidelines and sediment screening values, only Cr, Hg and Ni were high enough to cause detrimental effects in aquatic organisms. The potential ecological risk factor (Er i ) and potential ecological risk also revealed low to moderate ecological risk. Comprehensively, the river was in the uncontaminated to moderately contaminated level with low ecological risk.

Compositions, source apportionment and health risks assessment of fine particulate matter in naturally-ventilated schools

Good indoor air quality in school environment is crucial for teaching and learning processes, as well as student development. This study aims to identify the composition of PM2.5 and the main sources of it which influence the indoor and outdoor school environment. The PM2.5 sampling was conducted using a portable low volume air sampler and took place at three different primary schools. The chemical composition of PM2.5 is comprised of water-soluble inorganic ions (WSII) and potentially toxic trace metals. WSII (Cl−, NO3−, SO42−, Na+, NH4+, K+, Mg2+, Ca2+) were analysed using ion chromatography (IC) and trace metals concentrations (Al, Fe, Zn, Cr, Cu, Mn, Pb, Ni, As, Co, Cd) using inductively coupled plasma-mass spectrometry (ICP-MS). The results showed that the highest average for PM2.5 concentrations in an indoor classroom was recorded at the school located in the industrial area (23.5 μg/m3) followed by urban (18.6 μg/m3) and suburban (9.58 μg/m3). The indoor to outdoor (I/O) ratio values for PM2.5 concentrations were slightly above one, indicating that open doors and windows highly affected indoor PM2.5 concentrations. Source apportionment analysis indicated that the sources of both indoor and outdoor PM2.5 were mixed of natural (crustal, mineral dust and sea salt) and anthropogenic (vehicle, industrial and biomass burning). The hazard quotient (HQ) value was lower than the acceptable limits. The excess lifetime cancer risk (ELCR) value for all three stations, however, was found to be slightly higher than the acceptable level (1.0E-06) for Cr and Ni.

Stable isotope fractionation of thallium as novel evidence for its geochemical transfer during lead‑zinc smelting activities

Thallium (Tl) is a highly toxic trace metal. Lead (Pb)‑zinc (Zn) smelting, which is a pillar industry in various countries, is regarded as one of the dominant anthropogenic sources of Tl contamination in the environment. In this study, thallium isotope data have been evaluated for raw material and a set of industrial wastes produced at different stages of Pb-Zn smelting in a representative large facility located by the North River, South China, in order to capture Tl isotope signatures of such typical anthropogenic origin for laying the foundation of tracking Tl pollution. Large variations in Tl isotopic compositions of raw Pb-Zn ores and solid smelting wastes produced along the process chain were observed. The ε205Tl values of raw Pb-Zn ores and return fines are −0.87 ± 0.26 and −1.0 ± 0.17, respectively, contrasted by increasingly more negative values for electrostatic precipitator dust (ε205Tl = −2.03 ± 0.14), lime neutralizing slag (ε205Tl = −2.36 ± 0.18), and acid sludge (ε205Tl = −4.62 ± 0.76). The heaviest ε205Tl (1.12 ± 0.51) was found in clinker. These results show that isotopic fractionation occurs during the smelting processes. Obviously, the lighter Tl isotope is enriched in the vapor phase (−3.75 ε205Tl units). Further XPS and STEM-EDS analyses show that Tl isotope fractionation conforms to the Rayleigh fractionation model, and adsorption of 205Tl onto hematite (Fe2O3) may play an important role in the enrichment of the heavier Tl isotope. The findings demonstrate that Tl isotope analysis is a robust tool to aid our understanding of Tl behavior in smelting processes and to provide a basis for source apportionment of Tl contaminations.

Modulatory Effects of Mercury (II) Chloride (HgCl2 ) on Chicken Macrophage and B-Lymphocyte Cell Lines with Viral-Like Challenges In Vitro.

Mercury (Hg) is a toxic trace metal ubiquitously distributed in the environment. Inorganic mercury (as HgCl2) can cause immunotoxicity in birds, but the mechanisms of action are still not fully resolved, especially with respect to responses to viral infections. To investigate the potential immunomodulatory effects of Hg2+ on specific cell types of the avian immune system, chicken macrophage (HD‐11) and B‐lymphocyte (DT40) cell lines were applied as in vitro models for the innate and adaptive immune systems, respectively. The cells were stimulated with synthetic double‐stranded RNA, which can be recognized by toll‐like receptor‐3 to mimic a viral infection. The Hg2+ showed concentration‐dependent cytotoxicity in both cell lines, with similar median effect concentrations at 30 µM. The cytotoxicity of Hg2+ was closely related to glutathione (GSH) depletion and reactive oxygen species induction, whereas the de novo synthesis of GSH acted as a primary protective strategy. Nitric oxide produced by activated macrophages was strongly inhibited by Hg2+, and was also influenced by cellular GSH levels. Cell proliferation, gene expression of microRNA‐155, and cellular IgM levels in B cells were decreased at noncytotoxic Hg2+ concentrations. The secretion of antiviral interferon‐α was induced by Hg2+ in both cell lines. Overall, our results suggest that Hg2+ exposure can cause immunomodulatory effects in birds by disrupting immune cell proliferation and cytokine production, and might result in disorders of the avian immune system. Environ Toxicol Chem 2021;40:2813–2824. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Contribution of industrial and traffic emissions to ultrafine, fine, coarse particles in the vicinity of industrial areas in Japan

Atmospheric particulate matter (PM) in industrial areas is typically enriched with potentially toxic trace metals. However, measurements of ultrafine particles (PM0.1) in industrial areas, and the source apportionment of PM0.1 based on these results, are limited. Robust source apportionment studies are therefore necessary in order to identify the source of toxic emissions and to develop measures for reducing such emissions. The present study sought to clarify the contributions to PM mass of ultrafine, fine (PM2.5), and coarse particles (PM10 – PM2.5) in an urban–industrial area with multiple emission sources. We performed both online measurements of PM at a high temporal resolution and size-resolved offline measurements. Source apportionments were then performed for each particle size range by combining a positive matrix factorization method applied to organic aerosol data measured using an aerosol mass spectrometer, a twin-site study, and elemental tracer methods, and then assigning PM mass concentrations to 13 emission sources. The major contributing emission sources for PM0.1 were automobile exhaust (30%) and coal combustion, possibly related to integrated steelworks (24%), in winter, and fuel combustion (39%) and automobile exhaust (11%) in summer. Despite conducting measurements at one of the most heavily polluted traffic intersections in Japan, more than half of the anthropogenic primary emissions of PM0.1 and PM2.5 measured at the intersection were derived from sources other than automobile exhaust emissions. Since PM emissions from stationary-source flue gas has historically been less well regulated than automobile exhaust emissions, further mitigation measures need to be implemented in order to reduce atmospheric PM levels.

Association between placental metal exposure and NICU Network Neurobehavioral Scales (NNNS) profiles in the Rhode Island Child Health Study (RICHS)

BACKGROUND AND AIM: Exposure to even low levels of toxic metals has been linked to cognitive and behavioral deficits in children. Our prior work has demonstrated the placenta’s role in programming newborn health, and that placenta function can be affected by metals exposures. In this study, we hypothesized that placental trace metals can lead to poor neurobehavioral performance and so assessed the associations between placental toxic trace metals, cadmium, manganese, and lead, and neurobehavioral performance indicated through the NNNS in newborns. METHODS: A hospital-based birth cohort, RICHS enrolled infants 37 weeks gestation and oversampled for infants born either small or large for gestational age (n= 840). Placental tissue was collected within 2 hours of birth, and 24 metals’, metalloids’, and nutrient elements’ concentrations were determined using inductively couple plasma mass spectrometry. NNNS assessment was carried out by certified psychometrists from 24-72 hours after birth (n=625). Latent profile analysis (LPA) was used to define neurobehavior profiles based on 12 NNNS summary scales. Multinomial regression was used to examine the association between placental metals concentrations and neurobehavioral profile membership controlled for confounders (infant sex, maternal age, race, BMI, education status and tobacco smoking during pregnancy). RESULTS:The optimal LPA fit was a 5-profile model. The 12 NNNS summary scores were significantly different across the five profiles. Adjusted models showed that a doubling of placental cadmium concentration was associated with a 2.4 fold increased odds of newborns belonging to the atypical neurobehavioral profile compared to the typical performing profile (95%CI: [1.4, 3.4]). Participants with detectable placental lead levels also had increased odds of belonging to the atypical profile (OR: 3.4, 95%CI: [2.1, 4.8]). CONCLUSIONS:Placental toxic heavy metals including cadmium and lead were associated with atypical neurobehavioral performance at birth and provided additional evidence of the importance of the placenta in newborn health. KEYWORDS: heavy metals, children's environmental health, neurodevelopmental outcomes, environmental epidemiology

Secondary Sulfate Minerals from Pyrite Oxidation in Lanmuchang Hg-Tl Deposit, Southwest Guizhou Province, China: Geochemistry and Environmental Significance

Thallium (Tl) is a highly toxic trace metal posing a significant threat to human health. Tl pollution in soils and chronic Tl poisoning related to Tl-rich sulfides weathering in the Lanmuchang mine of southwest Guizhou province, China, have been intensively studied in recent years. And yet, there are few studies on the role of secondary sulfate minerals associated with Tl mobility in this area. The sulfate minerals were characterized by XRD and SEM-EDS. The concentrations of Tl and other elements were determined by ICP-MS. The results show that sulfate minerals are predominantly melanterite, halotrichite, and fibroferrite. The average contents of Tl in rock, sulfate minerals, and soil samples were 156.4, 0.11, and 72.1µg g-1, respectively. This study suggests that Tl in the mineralized rocks entered soils by pyrite oxidation with less scavenged of the sulfate minerals. The dissolution of the ferric sulfate minerals accelerates pyrite oxidation and maintains soil acidity, and this likely enhances Tl mobility from soil to crops.

Occurrences of potentially toxic trace metals in groundwater of the state of Punjab in northern India

In present study, a total of 275 representative water samples (263 groundwater, 8 canal water, 2 samples from Sutlej River and 2 samples from Buddha Nala) were collected and analysed. The sampling was carried out in the month of August, September, and October of 2019. These samples were analysed for the Arsenic (As-total), Aluminium (Al), Iron (Fe), Manganese (Mn), Zinc (Zn), Copper (Cu), Chromium (Cr), Cadmium (Cd), Nickel (Ni), and Lead (Pb). The result found that 3.8 % of the analysed groundwater samples have As concentrations above acceptable limit (10 μg/L) and ~0.38 % samples exceeded the permissible limit of 50 μg/L. Iron concentration exceeded the acceptable limit of 0.3 mg/L for drinking water in ~14.83 % groundwater samples. The mean concentration of iron was found 252 μg/L and 3810 μg/L for groundwater and canal water, respectively. It was observed that some samples have concentrations more than acceptable limits in the cities of Ludhiana, SBS Nagar, Rupnagar, SAS Nagar districts and in parts of Mansa, Amristar and Gurdaspur districts of the state of Punjab. Iron was found exceeding the permissible limit in the villages like, Moran wara (Firozepur), Churian (Firozepur), Manewal (Ludhiana), PandKhokhan (Muktsar) and Pakki Kalan (Faridkot).

Toxic Elements in Soil and Rice in Ecuador

The concentration of trace toxic metals (Cr, Zn, As, Pb, Cd, Cu, and Ni) in soil and rice plants, including the stems, leaves, and grain, from the main rice-producing provinces in Ecuador, was determined. Additionally, the soils were analyzed to determine their properties, composition, total content, bioavailable fraction, and geochemical fractions of toxic elements. Approximately 30% of soil samples in the case of Cr and Cu and 10% of samples in the case of Ni exceeded the legal thresholds for Ecuador. Moreover, for Cr and Cu, approximately 4% and 13% of samples, respectively, exceeded the threshold value of 100 mg kg−1 proposed for these two elements in several international regulations. Concentrations of As, Pb, and Cd in the soils were below the threshold values established both by Ecuadorian laws and by other countries. The concentrations of metals in rice plants did not correlate linearly with the total metal concentrations in the soil, nor with their bioavailability. However, the bioconcentration factors for As, Cd, Cu, Ni, and Zn could be predicted from bioavailability by a power law with exponents ranging from −0.724 to −1.625, which is typical of accumulator plants, where trace metal homeostasis plays an important role.

Health risk assessment induced by trace toxic metals in tap drinking water: Condorcet principle development

Acute exposure to trace metals (TMs) in water is hazardous to human health. The average concentrations (Cavg.) and carcinogenic (CAR) and non-carcinogenic (non-CAR) risks of eight TMs to World Health Organization's (WHO) guidelines and national standard limits (NSLs)were determined. The Cavg. and (the range) of As, Hg, Cd, Pb, Co, Cr, Ni, and Zn were measured as 4.29 ± 0.57 μg L−1 (1.12–10.27 μg L−1), 0.22 ± 0.10 μg L−1 (ND-1.05 μg L−1), 0.31 ± 0.18 μg L−1 (ND-1.80 μg L−1), 4.66 ± 0.32 μg L−1 (0.10–14.22 μg L−1), 24.61 ± 4.65 μg L−1 (3.11–67.25 μg L−1), 16.86 ± 5.54 μg L−1 (5.12–34.61 μg L−1), 14.07 ± 4.37 μg L−1 (3.79–31.39 μg L−1), and 268.42 ± 75.82 (87.29–561.22 μg L−1), respectively. The Cavg. of Co and Hg exceeded the WHO and NSLs. The non-CAR risk assessment was used to order the TMs according to the total target hazard quotient (TTHQ) As > Pb > Cr > Co > Zn > Hg > Ni > Cd. None of the investigated age groups are at risk As there is a low Cavg of all trace metals (i.e., the THQ is > 1). The age groups were ranked based on THQ and incremental lifetime cancer risk (ILCR) As < 1 year, >1–10 years, > 11–19 years, and > + 20 years. The ILCR of As for all the age groups was >10−4, whereas for Pb it was <10−6. Cumulative carcinogenic risk (CCR) for As and Pb was at a safe threshold risk (>10−4) for all the age groups.

Profiling of Circulatory Elements Reveals Alteration of Essential and Toxic Trace Metals in Crohn’s Disease

The status of essential and toxic trace metals in the blood of Crohn's disease (CD) patients is unexplained. This study aimed to provide the first elemental profiling of the most recognized essential elements (Mn, Cu, Zn, Se) and selected toxic trace elements (As, Cd, Pb, and U) in sera and cell lysate (CL) samples of CD patients (n = 84). The results were compared with sex- and age-matched samples from the control group (CG). CD sera contained significantly higher levels of Mn, As, Cd, Pb, and U than did CG sera. An identical pattern, with the added inclusion of Cu (also higher in CD patients than in the CG), was obtained for CL samples. However, the most important finding was hypermanganesemia, which indicates that Mn could act as a toxic trace metal in CD. As, Cd, and U were the most significant toxic elements that showed antagonistic effects on the extrusion of essential Mn and Cu. Circulatory system screening markers for CD are hereby proposed (Mn/Cu, Mn/As, and Mn/Pb ratios). These three metal ratios were strongly and significantly correlated with F-Calprotectin levels, and deserve consideration as new markers of CD. The target metals and metal ratios should be taken into consideration as novel initiating and/or modifying factors for CD.

Agronomic performance and food safety of strawberry cultivated on a remediated sediment

A marine sediment phytoremediated and homogenized by landfarming was tested for its potential recycle as growing media in horticulture. Two strawberry cultivars, Camarosa and Monterey, were grown on remediated sediment alone (TS100), commercial peat/pumice based growing medium (TS0) and a mixture 1:1 in volume of sediment and peat (TS50). Chemical fertility and strawberry production and safety of produced food were monitored for three consecutive productive seasons on the same growing media. During the first year of cultivation, plants grown on sediment-based media showed a significantly lower biomass production and fruit yield compared with peat, mainly due to the sediment low fertility. In the subsequent two years, the plant re-cultivation improved the sediment structure and N mineralization, and on the third cultivation year both strawberry cultivars showed higher fruit productivity and no accumulation of potentially toxic trace metals. The produced fruits did non accumulate high concentrations of trace metals, and risk assessment showed no risks for human health related to the consumption of strawberry produced on sediment-based growing media. We concluded that a phytoremediated sediment could be recycled as an ingredient of soilless growing media for reducing the environmental impact of plant nursery production and posing no risks for human health. These results show that reclaimed sediments could be reconsidered as a component material category in the new EU regulation on fertilizers.

Effects of chemical and natural ageing on the release of potentially toxic metal additives in commercial PVC microplastics

Various chemical substances, such as potentially toxic trace metals, are used as plastic additives to improve the performance of polymers and extend the service life of plastic products. However, these added trace metals are likely released from plastic into the environment when the plastic becomes a pollutant, although the process is poorly understood. In this study, chemical ageing of commercial polyvinyl chloride (PVC) microplastics using hydrogen peroxide (H2O2) and natural ageing of PVC that had been added to an alkaline paddy soil were undertaken to evaluate the potential release of trace metals from PVC. Enhanced release of trace metals from PVC with the increasing H2O2 concentrations was observed, in which the released Pb was 1–2 orders of magnitude higher than other metals (p < 0.01). The released Cr, Ni, Pb, Cu, Zn, Cd and Mn accounted for 87.37%, 79.27%, 22.02%, 20.93%, 17.06%, 15.11%, and 11.02% of their total concentrations (0.28 ± 0.03, 0.08 ± 0.01, 13.67 ± 0.18, 1.07 ± 0.02, 2.20 ± 0.18, 0.05 ± 0.00 and 1.26 ± 0.08 mmol kg−1) in PVC after ageing with 30% H2O2, respectively. Compared with the control treatment without PVC addition, the concentrations of CaCl2-extractable Cu, Mn, Ni, Pb, and Zn in the soil treated with 5% PVC are significantly increased after incubation for 60 days (p < 0.01). In conclusion, chemical and natural ageing have the potential to lead to the release of Cu, Mn, Ni, Pb, and Zn from the commercial PVC into aquatic and terrestrial environments.

Impact of Essential and Toxic Trace Metals on Thyroid Health and Cancer: A Review

Impact of Essential and Toxic Trace Metals on Thyroid Health and Cancer: A Review