Assessing the health risks of heavy metals and seasonal minerals fluctuations in Camellia sinensis cultivars during their growth seasons.

The risk assessment of heavy metals in tea is extremely imperative for the health of tea consumers. However, the effects of varietal variations and seasonal fluctuations on heavy metals and minerals in tea plants remain unclear. Inductively coupled plasma optical emission spectrometry (ICP-OES) was used to evaluate the contents of aluminum (Al), manganese (Mn), magnesium (Mg), boron (B), calcium (Ca), copper (Cu), cobalt (Co), iron (Fe), sodium (Na), zinc (Zn), arsenic (As), cadmium (Cd), chromium (Cr), nickel (Ni), and antimony (Sb) in the two categories of young leaves (YL) and mature leaves (ML) of tea (Camellia sinensis) cultivars throughout the growing seasons. The results showed significant variations in the contents of the investigated nutrients both among the different cultivars and growing seasons as well. Furthermore, the average concentrations of Al, Mn, Mg, B, Ca, Cu, Co, Fe, Na, Zn, As, Cd, Cr, Ni, and Sb in YL ranged, from 671.58-2209.12, 1260.58-1902.21, 2290.56-2995.36, 91.18-164.68, 821.95-5708.20, 2.55-3.80, 3.96-25.22, 37.95-202.84, 81.79-205.05, 27.10-69.67, 0.028-0.053, 0.065-0.127, 2.40-3.73, 10.57-12.64, 0.11-0.14 mg kg-1, respectively. In ML, the concentrations were 2626.41-7834.60, 3980.82-6473.64, 3335.38-4537.48, 327.33-501.70, 9619.89-13153.68, 4.23-8.18, 17.23-34.20, 329.39-567.19, 145.36-248.69, 40.50-81.42, 0.089-0.169, 0.23-0.27, 5.24-7.89, 18.51-23.97, 0.15-0.19 mg kg-1, respectively. The contents of all analyzed nutrients were found to be higher in ML than in YL. Target hazard quotients (THQ) of As, Cd, Cr, Ni, and Sb, as well as the hazard index (HI), were all less than one, suggesting no risk to human health via tea consumption. This research might provide the groundwork for essential minerals recommendations, as well as a better understanding and management of heavy metal risks in tea.

Pollution indices of selected metals in tea (Camellia sinensis L.) growing soils of the Upper Assam region divulge a non-trifling menace of National Highway.

The study investigated the influence of a National Highway (NH) traversing tea estates (TEs) on heavy metal (HM) contamination in the top soils of Upper Assam, India. The dispersion and accumulation of six HMs, viz. cadmium (Cd), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), and zinc (Zn), within tea-growing soils were assessed using diverse indices: contamination factor (CF), degree of contamination (DC), enrichment factor (EF), geo-accumulation index (Igeo), modified degree of contamination (MDC), Nemerow pollution index (PINemerow), pollution load index (PLI), potential ecological risk factor (Eri), and potential ecological risk index (RI). The order of HM prevalence was Fe > Mn > Zn > Ni > Cu > Cd. Elevated Cd levels near the NH prompted immediate attention, while Cd and Zn showed moderate pollution in CF, EF, and RI. The remaining metals posed minimal individual risk (Eri< 40), resulting in an overall contamination range of "nil to shallow," signifying slight contamination from the studied metals. From MDC values for investigated metals, it was found to be "zero to very low degree of contamination" at all locations except the vicinity of NH. Soil pollution, as determined by PLI, indicated unpolluted soils in both districts, yet PINemerow values indicated slight pollution. The statistical analysis revealed that there is a significant decrease in most of the indices of HM as the distance from NH increases. The application of multivariate statistical techniques namely Principal Component Analysis and Cluster Analysis showed the presence of three distinct homogenous groups of distances based on different indices. This investigation underscores NH-associated anthropogenic effects on TE soil quality due to HM deposition, warranting proactive mitigation measures.

Coupling electrokinetic remediation with flushing using green tea synthesized nano zero-valent iron/nickel to remediate Cr (VI).

This study focuses on a flushing-electrokinetic remediation technology of hexavalent chromium from the chromium slag dump site. A suspension of nanoscale zero-valent iron/nickel fabricated from green tea (GT-nZVI/Ni), was employed as an eluent to degrade Cr (VI) and enhance the remediation effectiveness of a single EK. The removal efficiency of Cr (VI) was compared under different voltages, electrode spacings and pH values of the anolyte. The results demonstrated that the combined flushing and EK achieved a removal rate of Cr (VI) in the soil throughout all the experiments ranging from 83.08 to 96.97% after 120 h. The optimal result was obtained when the voltage was 28 V, the pH value of anolyte was 3 and the electrode spacing was 15 cm. The removal of Cr (VI) reached 91.49% and the energy consumption was 0.32606 kW·h·g-1. The underlying mechanisms responsible for the removal of Cr (VI) by GT-nZVI/Ni flushing-EK primarily involved electromigration, reduction and adsorption co-precipitation processes. The fractionation analysis of Cr (VI) concentration in the soil after remediation showed that the presence of GT-nZVI/Ni facilitated the conversion of Cr (VI) into oxidizable and residual states with low mobility and toxicity. The results of toxicity characteristic leaching procedure (TCLP) indicated that the leaching concentration of Cr (VI) was below 1 mg·L-1, complying with the standards set by the Environmental Protection Agency. Additionally, the phytotoxicity testing revealed that the germination index (GI) of the remediated soil reached 54.75%, indicating no potential harm to plants.

Environmental bioavailability of arsenic, nickel and chromium in soils impacted by high geogenic and anthropogenic background contents.

High arsenic, chromium and nickel in soils can pose a hazard to the ecosystem and/or human health. Large areas can be affected by elevated potentially toxic elements (PTE) background contents, entailing a significant effort for managing the potential risk. Assessing the environmental hazard associated to PTE-contaminated soils requires the determination of soil PTE environmental bioavailability, which reflects the capacity of these elements to be transferred to living organisms. Here we assess the environmental bioavailability of As, Cr and Ni in topsoils from the Liège basin and Belgian Lorraine, two areas in Wallonia, Belgium, affected by elevated As, Cr and Ni background contents. The source of soil As, Cr and Ni differs in Liège and Lorraine: anthropogenic in the former location and geogenic in the latter. The environmental bioavailability of PTE was determined using two complementary approaches: (1) by chemical fractionation with the Community Bureau of Reference (BCR) three-step sequential extraction protocol and (2) by estimating the phytoavailability using a plant-based biotest (Lolium multiflorum as plant model). The results show that total As (6-130 mg·kg-1), Cr (15-268 mg·kg-1), and Ni (8-140 mg·kg-1) contents in the Liège and Lorraine soils frequently exceed the soil clean-up standards. However, no positive correlation was found between the total contents and BCR extraction results or rye-grass contents, except for As in Liège soils. Total As, Cr or Ni contents surpassing soil standards do not necessarily result in elevated mobile, potentially mobilizable and phytoavailable contents. In general, environmental bioavailability of As, Cr and Ni is higher in soils from Liège basin compared to those sampled in Belgian Lorraine. The mobile and potentially mobilizable fractions of As, Cr and Ni account for <30 % of their total contents following the BCR extractions. Our study provides valuable information for sustainable management at the regional scale of soils containing high PTE contents.

Metal(loid) Analysis of Commercial Rice from Malaysia using ICP-MS: Potential Health Risk Evaluation.

Rice is a predominant staple food in many countries. It is a great source of energy but can also accumulate toxic and trace metal(loid)s from the environment and pose serious health hazards to consumers if overdosed. This study aims to determine the concentration of toxic metal(loid)s [arsenic (As), cadmium (Cd), nickel (Ni)] and essential metal(loid)s [iron (Fe), selenium (Se), copper (Cu), chromium (Cr), cobalt (Co)] in various types of commercially available rice (basmati, glutinous, brown, local whites, and fragrant rice) in Malaysia, and to assess the potential human health risk. Rice samples were digested following the USEPA 3050B acid digestion method and the concentrations of metal(loid)s were analyzed using an inductively coupled plasma mass spectrometry (ICP-MS). Mean concentrations (mg/kg as dry weight) of metal(loid)s (n=45) across all rice types were found in the order of Fe (41.37)>Cu (6.51)>Cr (1.91)>Ni (0.38)>As (0.35)>Se (0.07)>Cd (0.03)>Co (0.02). Thirty-three percent and none of the rice samples surpassed, respectively, the FAO/WHO recommended limits of As and Cd. This study revealed that rice could be a primary exposure pathway to toxic metal(loid)s, leading to either noncarcinogenic or carcinogenic health problems. The non-carcinogenic health risk was mainly associated with As which contributed 63% to the hazard index followed by Cr (34%), Cd (2%), and Ni (1%). The carcinogenic risk to adults was high (>10-4) for As, Cr, Cd, and Ni. The cancer risk (CR) for each element was 5 to 8 times higher than the upper limit of cancer risk for an environmental carcinogen (<10-4). The findings from this study could provide the metal(loid)s pollution status of various types of rice which are beneficial to relevant authorities in addressing food safety and security-related issues.

Preparation of COF-coated nickel foam adsorbents for dispersive solid-phase extraction of 16 polycyclic aromatic hydrocarbons from Chinese herbal medicines.

Covalent organic framework coated nickel foam (NF@COF) was prepared as a sorbent for the dispersive solid phase extraction (DSPE) of polycyclic aromatic hydrocarbons (PAHs) from Chinese herbal medicines (CHMs) prior to their determination by gas chromatography-mass spectrometry (GC-MS). The structure and morphology of the as-synthesized NF@COF were characterized by different techniques. Various key parameters affecting the performance of the DSPE method, including the amount of sorbent, desorption solvent, desorption volume and time, extraction time, and sample volume, were investigated. Under the optimized conditions, NF@COF combined with GC-MS was successfully applied to the determination of 16 PAHs in CHMs. The method showed wide linearity (20-2000 ng mL-1), low limits of determination (0.3-2.7 ng mL-1), and high recoveries (78.0-124%). These results revealed that NF@COF has the potential for efficient extraction of PAHs from complex samples.

Simultaneous immobilization of heavy metals and nutrient elements in contaminated sediment using a novel composite agent product.

In this research, an innovative type of sediment resource treatment agent (SRA) was synthesized successfully, which could immobilize ammonia nitrogen (NH3-N), total phosphorus (TP), potassium (K), and simultaneously stabilize cadmium (Cd), lead (Pb), chromium (Cr), copper (Cu), nickel (Ni), and zinc (Zn) in dredged sediment. The effects of SRA dosage on stabilizing the nutrient elements and heavy metals were investigated. The results demonstrated that the increase of SRA dosage significantly enhanced the stabilization of nutrients and heavy metals. The 14-day rainwater infiltration and rainwater scouring experiments were carried out. With the simulation test of rainwater infiltration, the stabilization ratios of Cr, Cu, Ni, Pb, Zn, Cd, NH3-N, TP, and K with 2% SRA addition reached 80.8%, 76.8%, 80.3%, 77.5%, 78.0%, 72.7%, 64.3%, 73.9%, and 73.9%, respectively. Under the action of rainwater scouring, the stabilization ratios of Cr, Cu, Ni, Pb, Zn, Cd, NH3-N, TP, and K with 6.4% SRA addition reached 84.6%, 84.0%, 77.6%, 87.3%, 80.0%, 61.5%, 76.2%, 77.8%, and 91.7%, respectively. Therefore, the results demonstrate that SRA is an excellent composite material in stabilizing heavy metals while reserving the nutrients in dredged sediment, thus showing great potential in the application for dredged sediment resource treatment.

The Effects of Nickel and Copper on Tropical Marine and Freshwater Microalgae Using Single and Multispecies Tests.

Microalgae are key components of aquatic food chains and are known to be sensitive to a range of contaminants. Much of the available data on metal toxicity to microalgae have been derived from temperate single-species tests with temperate data used to supplement tropical toxicity data sets to derive guideline values. In the present study, we used single-species and multispecies tests to investigate the toxicity of nickel and copper to tropical freshwater and marine microalgae, including the free-swimming stage of Symbiodinium sp., a worldwide coral endosymbiont. Based on the 10% effect concentration (EC10) for growth rate, copper was two to four times more toxic than nickel to all species tested. The temperate strain of Ceratoneis closterium was eight to 10 times more sensitive to nickel than the two tropical strains. Freshwater Monoraphidium arcuatum was less sensitive to copper and nickel in the multispecies tests compared with the single-species tests (EC10 values increasing from 0.45 to 1.4 µg Cu/L and from 62 to 330 µg Ni/L). The Symbiodinium sp. was sensitive to copper (EC10 of 3.1 µg Cu/L) and less sensitive to nickel (EC50 >1600 µg Ni/L). This is an important contribution of data on the chronic toxicity of nickel to Symbiodinium sp. A key result from the present study was that three microalgal species had EC10 values below the current copper water quality guideline value for 95% species protection in slightly to moderately disturbed systems in Australia and New Zealand, indicating that they may not be adequately protected by the current copper guideline value. By contrast, toxicity of nickel to microalgae is unlikely to occur at exposure concentrations typically found in fresh and marine waters. Environ Toxicol Chem 2023;42:901-913. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Determination of polycyclic aromatic hydrocarbons in Chinese herbal medicines by gas chromatography-mass spectrometry with graphene-functionalized nickel foam.

Graphene-functionalized nickel foam (NF) sorbent materials were prepared and characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Thermogravimetric analysis. For the separation and detection of polycyclic aromatic hydrocarbons (PAHs) in five Chinese medicine samples, namely dandelion, fructus aurantii, peppermint, mulberry leaf and embryo chrysanthemum, a method combining dispersive micro-solid phase extraction and gas chromatography-mass spectrometry (GC-MS) was developed. Four conditions affecting the extraction efficiency, such as the type of desorption solvent, the amount of sorbent, the extraction time and the volume of water sample, were optimized. The results of the methodological validation showed that NF@SiO2@G was able to adsorb PAHs well and with good reproducibility. All analytes showed good linearity in the concentration range of 20-2000 ng/mL with coefficient of determination R2≥0.9956. The limit of detection was 0.98-13.34 ng/mL, and the limit of quantification ranged from 3.25 to 44.47 ng/mL. Both the intra-day and inter-day precision were lower than 15.46%, and the spiked recoveries were in the range of 75.5-118.4%. The total contents of the 16 PAHs contained in these five Chinese herbal medicines (CHMs) were varied from 450 to 1557 µg/kg. The results indicated that the graphene-functionalized NF sorbent combined with GC-MS can effectively detect PAHs in CHMs.

Phytoextraction of nickel, lead, and chromium from contaminated soil using sunflower, marigold, and spinach: comparison of efficiency and fractionation study.

Heavy metals in soil pose a serious threat through their toxic effect on the human food chain. Phytoremediation is a clean and green potentially cost-effective technology in remediating the heavy metal-contaminated soil. However, the efficiency of phytoextraction is very often limited by low phytoavailability of heavy metals in soil, slow growth, and small biomass production of hyper-accumulator plants. To solve these issues, accumulator plant(s) with high biomass production and amendment(s) which can solubilize metals in soil is required for better phytoextraction. A pot experiment was conducted to assess the efficiency of phytoextraction of sunflower, marigold, and spinach as affected by the incorporation of Sesbania (solubilizer) and addition of gypsum (solubilizer) in nickel (Ni)-, lead (Pb)-, and chromium (Cr)-contaminated soil. A fractionation study was conducted to study the bioavailability of the heavy metals in contaminated soil after growing the accumulator plants and as affected by using soil amendments (Sesbania and gypsum). Results showed that marigold was the most efficient among the three accumulator plants in phytoextraction of the heavy metals in the contaminated soil. Both sunflower and marigold were able to reduce the bioavailability of the heavy metals in the post-harvest soil, which was reflected in their (heavy metals) lower concentration in subsequently grown paddy crop (straw). The fractionation study revealed that carbonate and organically bound fractions of the heavy metals control the bioavailability of the heavy metals in the experimental soil. Both Sesbania and gypsum were not effective in solubilizing the heavy metals in the experimental soil. Therefore, the possibility of using Sesbania and gypsum for solubilizing heavy metals in contaminated soil is ruled out.

Pollution impact assessment of secondary iron smelting on soil and some medicinal herbs grown at Fasina community in Ile-Ife, Nigeria.

Use of medicinal herbs is now gaining popularity especially among the low-income people because it is cheap, readily available and its "seeming" lack of side effects. However, environmental pollution is a potential threat to its continued use. This study examines the effect of air pollution on the soil and consequently on the medicinal herbs grown on such soils. Soil and four medicinal herbs, Chromolaena odorata, Vernonia amygdalina, Carica papaya and Ocimum gratissimum, commonly used in the south western part of Nigeria either as purely medicinal herbs, soup vegetables or both were carefully harvested from Fasina, a polluted area, and Moro, a relatively unpolluted area, all in Ile-Ife, Nigeria. Samples were prepared following standard practice and analysed for nickel, chromium, cadmium and lead using atomic absorption spectroscopy (AAS). The results showed that elemental concentrations at the two locations were within the permissible limit for both soil and herbs, the statistical test also established no significant difference between the two locations. However, toxic metals concentrations (chromium, cadmium and lead) were found higher at the polluted site while that of the essential metal, nickel, was higher at the unpolluted site. Of the four metals, cadmium has the highest transfer ratio (0.39 and 0.34) while lead has the least (0.21 and 0.25) for Moro and Fasina sites respectively. Similarly, Chromolaena odorata has the highest transfer ratio (0.34) while Carica papaya has the least (0.28). In conclusion, gradual build-up of the toxic metals at the polluted site is evident and may eventually contaminate the herbs.

Comparison and Risk Assessment of Macroelements and Trace Metals in Commercial Teas from Different Regions of China.

Tea (Camellia sinensis L.) is one of the most widely consumed non-alcoholic beverages worldwide. In the present study, 73 commercial tea samples were collected from tea plantations in the Southwest, South, Jiangnan, and Jiangbei regions of China. The contents of four macroelements (phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg)) and 15 trace metals (arsenic (As), cadmium (Cd), chromium (Cr), mercury (Hg), lead (Pb), zinc (Zn), aluminium (Al), copper (Cu), manganese (Mn), iron (Fe), nickel (Ni), thorium (Th), thallium (Tl), rubidium (Rb) and barium (Ba)) in tea samples were determined. The mean concentrations of As, Cd, Cr, Hg, Pb, Zn, Al, Cu, Mn, Fe, Ni, Th, Tl, Rb and Ba were in the range of 0.02-0.61, 0.008-0.126, 0.09-1.12, 0.001-0.012, 0.07-1.62, 19.5-73.2, 170-2100, 5.9-43.3, 228-2040, 60-337, 2.09-17.95, 0.002-0.08, 0.004-0.409, 0-150.50 and 3.1-41.2 µg/g, respectively, which were all lower than the maximum permissible limits stipulated by China (NY/T 288-2012, NY 659-2003). The target hazard quotients of each heavy metal were lower than one, and the combined risk hazard index of all heavy metals for adults was in the range of 0.10-0.85; therefore, there was no significant carcinogenic health risks to tea drinking consumers under the current dietary intake. Significant differences were found in the content of trace elements (Zn, Cu, Fe, Ni, Th, Tl, Rb and Ba) (p < 0.05); however, no significant differences were found in the content of macroelements (P, K, Ca and Mg) and trace metals (As, Cd, Cr, Hg, Pb, Al and Mn) in teas from different regions. Therefore, the region did not affect the heavy metal exposure risk. Correlation coefficient and principal component analyses were performed to determine the source of the elements. Three principal factors were obtained: factor 1 was positively related to Ca, Mg, As, Cd, Cr, Hg, Pb, Al, Mn, Fe and Th (32.63%); factor 2 to P, Zn, Cu and Ni (18.64%) and factor 3 to K and Rb (10.10%). Thus, the elements in the same factor might originate from the same source. This study provides an essential basis to understand the variance and potential risks of different elements in tea from different regions of China.

Occurrence and Distribution of Heavy Metals in Mining Degraded Soil and Medicinal Plants: A Case Study of Pb/Zn Sulfide Terrain Northern Areas, Pakistan.

Mining activities have serious environmental impacts, thus releasing heavy metals (HMs) such as cadmium (Cd), lead (Pb), chromium (Cr), zinc (Zn) and nickel (Ni) into the surrounding environment. The current paper investigated the impacts of mining activities of Pb-Zn sulfide on soil and medicinal plants. Hence, soil samples (n = 36) and medicinal plants (n = 36) samples were collected, acid extracted and were analyzed through Inductively Coupled Plasma Mass Spectrometry (ICP-MS) for HMs quantification. Our results showed that mineralized zones showed high HMs enrichment levels as compared to non-mineralized zones. Various Indices for HMs assessment revealed that the contaminated soil of the study area had low to extreme level. The mean concentrations of HMs in mining degraded soil and medicinal plants were significantly higher (p ≤ 0.01) and were found in order of Zn > Pb > Cr > Ni > Cd and Cr > Zn > Pb > Ni > Cd respectively. Similarly, some widely consumable medicinal plants showed good metal accumulation for Cd, Cr and Pb i.e., 3.57 mg kg1, 350 mg kg-1 and 335 mg kg-1 in C. sativa, while 5.9 mg kg-1, 276.9 mg kg-1 and 188.7 mg kg-1 in R. hestatus respectively. Hence, the present study recommended that medicinal plants grown in mining areas should be analyzed for HMs concentration before consumption.

Novel metallomic profiling and non-carcinogenic risk assessment of botanical ingredients for use in herbal, phytopharmaceutical and dietary products using HR-ICP-SFMS.

Knowledge of element concentrations in botanical extracts is relevant to assure consumer protection given the increased interest in plant-based ingredients. This study demonstrates successful multi-element investigations in order to address the lack of comprehensive profiling data for botanical extracts, while reporting for the first time the metallomic profile(s) of arnica, bush vetch, sweet cicely, yellow rattle, bogbean, rock-tea and tufted catchfly. Key element compositions were quantified using a validated HR-ICP-SFMS method (µg kg-1) and were found highly variable between the different plants: Lithium (18-3964); Beryllium (3-121); Molybdenum (75-4505); Cadmium (5-325); Tin (6-165); Barium (747-4646); Platinum (2-33); Mercury (5-30); Thallium (3-91); Lead (12-4248); Bismuth (2-30); Titanium (131-5827); Vanadium (15-1758); Chromium (100-4534); Cobalt (21-652); Nickel (230-6060) and Copper (1910-6340). Compendial permissible limits were not exceeded. Overall, no evidence of a health risk to consumers could be determined from consumption of the investigated plants at reasonable intake rates. Mathematical risk modelling (EDI, CDI, HQ, HI) estimated levels above safe oral thresholds only for Cd (16%) and Pb (8%) from higher intakes of the respective plant-derived material. Following high consumption of certain plants, 42% of the samples were categorised as potentially unsafe due to cumulative exposure to Cu, Cd, Hg and Pb. PCA suggested a potential influence of post-harvest processing on Cr, Ti and V levels in commercially-acquired plant material compared to wild-collected and farm-grown plants. Moreover, a strong correlation was observed between Pb-Bi, Be-V, Bi-Sn, and Tl-Mo occurrence. This study may support future research by providing both robust methodology and accompanying reference profile(s) suitable for the quality evaluation of essential elements and/or metal contaminants in botanical ingredients.

Mobile trace elements in sediments from lakes Hawassa, Koka, and Ziway in the Ethiopian Rift Valley.

The present work focuses on total concentrations of trace elements such as chromium (Cr), manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), selenium (Se), cadmium (Cd), and lead (Pb) and their operationally defined speciation in surface sediments from three Ethiopian Rift Valley Lakes (Hawassa, Koka, and Ziway). Total concentrations were determined using inductively coupled plasma-mass spectrometer (ICP-MS). A six-step sequential extraction was also applied to evaluate the mobilization potential of these elements. Compared with the consensus-based sediment quality guidelines (SQGs) developed for freshwater ecosystems, the total Zn concentration in sediments from Lakes Hawassa and Ziway, as well as Cr, Ni, and Zn in sediments from Lake Koka, was higher than the probable effect concentration (PEC), suggesting that these elements could have a negative effect on benthic organisms. The sequential extraction results showed that Cd, Mn, and Se were to a certain extent associated with the reversible fractions (F1-F3) in sediments, and thereby more mobile than the other investigated trace elements. Predictions of mobility of trace elements using the distribution coefficients (Kd) values were also in agreement with the sequential extraction results. Furthermore, multivariate statistical analyses showed that redox-sensitive fractions (F4 and F6) and the residual fraction (F7) were the dominant factors controlling most trace element mobility. Finally, applying the Risk Assessment Code (RAC) classification system, results showed that Mn in Lake Koka could pose a high risk, while Cd and Mn in Lake Hawassa as well as Cd, Mn, and Se in Lake Ziway sediments could pose medium risk to benthic organisms.

Nano-modified feather keratin derived green and sustainable biosorbents for the remediation of heavy metals from synthetic wastewater.

In this study, we employed a facile method to synthesize feather keratin derived biosorbents using water dispersed graphene oxide. The successful cross-linking of feather keratin with graphene oxide was investigated through X-ray photoelectrons spectroscopy (XPS), scanning and transmission electron microscopy, and Brunauer-Emmett-Teller (BET) analysis. The modifications resulted in increased surface area of the keratin proteins with substantial morphological changes including the development of cracked and rough patches on the surface. The chicken feather keratin/graphene oxide based biosorbents exhibited excellent performance for the simultaneous removal of metal oxyanions including arsenic (As), selenium (Se), chromium (Cr) and cations including nickel (Ni), cobalt (Co), lead (Pb), cadmium (Cd) and zinc (Zn) up to 99%, from polluted synthetic water containing 600 µgL-1 of each metal concentration in 24 h. The insights into the biosorption mechanism revealed that the electrostatic interaction, chelation and complexation primarily contributed to the removal of multiple heavy metal ions in a single treatment. This study has demonstrated that modification of chicken feather keratin with graphene oxide is an effective way to improve its sorption capacity for removing multiple trace metal ions from contaminated water.

Evaluation of hair analysis for determination of trace mineral status and exposure to toxic heavy metals in horses in the Netherlands.

Analysis of hair to gain insight into the trace mineral status and exposure to toxic heavy metals of horses is attractive because hair is an easily accessible sample material. To investigate the potential value of hair analysis in horses for determination of trace mineral and heavy metal concentrations, we analyzed mane hair and liver samples from 62 horses presented for slaughter at a facility in the Netherlands that receives horses from all regions of the country. Hair samples were cleaned in warm water. After acid digestion of hair and liver specimens, we quantified, with inductively coupled plasma-mass spectrometry, arsenic, cadmium, chromium, cobalt, copper, iron, lead, manganese, molybdenum, nickel, selenium, vanadium, and zinc in the digests. Based on Pearson product moment correlations, we found no statistically significant correlations between concentrations of trace minerals in liver and hair, with the exception of a slight correlation for copper that was too weak to be of clinical relevance. Our results do not support the use of hair to determine trace mineral status and exposure to toxic heavy metals in the horse under field conditions.

Ribosomal DNA copy number associated with blood metal levels in school-age children: A follow-up study on a municipal waste incinerator in Zhejiang, China.

To evaluate the body burdens of heavy metals and explore the impact of environmental metal exposure on ribosomal DNA (rDNA) or mitochondrial DNA (mtDNA) copy number (CN) variation in school-age children living near a municipal waste incinerator (MWI), we conducted a follow-up study in 2019. A total of 146 sixth-grade children from a primary school located 1.2 km away from the MWI were recruited for our study. Metals, including vanadium (V), chromium (Cr), manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), selenium (Se), cadmium (Cd), stannum (Sn), stibium (Sb), thallium (Tl), and lead (Pb), were determined by an inductively coupled plasma mass spectrometer method. Real-time qPCR was used to measure the rDNA and mtDNA CN. The blood metal levels followed this order: Zn > Cu > Se > Pb > Mn > Sb > As > Ni > Cd > Co > Cr > Sn > V > Tl. Blood Cr level was significantly correlated with 18 S, 2.5 S, and 45 S CN (ß = -0.25, -0.22, -0.26, p < 0.05); Ni was correlated with 5 S (ß = -0.36, p < 0.01); Cu was correlated with 28 S, 18 S, and 5.8 S (ß = -0.24, -0.24, -0.23, p < 0.05); while Zn was correlated with 18 S, 5.8 S, and 45 S (ß = -0.28, -0.32, -0.26, p < 0.05). In conclusion, school-age children living near the MWI had lower blood metal levels compared to children recruited in 2013, while rDNA CN loss was found to be correlated to several heavy metals in these children.

Aerosol mass and size-resolved metal content in urban Bangkok, Thailand.

Inhalable particulate matter (PM) is a health concern, and people living in large cities such as Bangkok are exposed to high concentrations. This exposure has been linked to respiratory and cardiac diseases and cancers of the lung and brain. Throughout 2018, PM was measured in northern Bangkok near a toll road (13.87°N, 100.58°E) covering all three seasons (cool, hot and rainy). PM10 was measured in 24- and 72-h samples. On selected dates aerodynamic size and mass distribution were measured as 3-day samples from a fixed 5th floor inlet. Particle number concentration was measured from the 5th floor inlet and in roadside survey measurements. There was a large fraction of particle number concentration in the sub-micron range, which showed the greatest variability compared with larger fractions. Metals associated with combustion sources were most found on the smaller size fraction of particles, which may have implications for associated adverse health outcomes because of the likely location of aerosol deposition in the distal airways of the lung. PM10 samples varied between 30 and 100 µg m-3, with highest concentrations in the cool season. The largest metal fractions present in the PM10 measurements were calcium, iron and magnesium during the hot season with average airborne concentrations of 13.2, 3.6 and 2.0 µg m-3, respectively. Copper, zinc, arsenic, selenium, molybdenum, cadmium, antimony and lead had large non-crustal sources. Principal component analysis (PCA) identified likely sources of the metals as crustal minerals, tailpipe exhaust and non-combustion traffic. A health risk analysis showed a higher risk of both carcinogenic and non-carcinogenic health effects in the drier seasons than the wet season due to ingestion of nickel, arsenic, cadmium and lead.

Urinary metals as influencing factors of coronary heart disease among a population in Guangzhou, China.

The cardiovascular system is highly sensitive to toxic metal exposure and trace element dysregulation. However, previous findings relating to metal exposure and coronary heart disease (CHD) have partially been conflicting and difficult to exhibit the combined effect of metal mixtures. This case-control study investigated urinary concentrations of ten metal/metalloids among clinically-diagnosed CHD patients and healthy adults during May to December 2021 in Guangzhou, China. We found that cadmium (Cd) status in urine from CHD patients was remarkably higher than its reference, while chromium (Cr), nickel (Ni), copper (Cu) and selenium (Se) concentrations were lower (p < 0.05). Spearman correlation analysis showed that urinary arsenic (As) and Se were highly correlated (rs=0.830, p < 0.001), indicating their similar sources. Principal component analysis (PCA) exhibited denser distribution of Cd-Sn in cases than in controls. Logistic regression analysis exhibited significant associations between urinary Cd (adjusted OR: 1.965, 95% CI: 1.222-3.162), Se (0.787, 95% CI: 0.695-0.893), Ni (0.493, 95% CI: 0.265-0.916) and CHD risk. Quantile g-computation showed negative joint effect of metal mixtures on CHD (adjusted OR: 0.383, 95% CI: 0.159-0.932) (p < 0.05), suggesting the need for supplementing essential trace elements. The negative partial effect was primarily attributed to Se and Ni, while positive partial effect was mainly due to tin (Sn) and Cd. Nevertheless, we also found a quantile increase of Cd-Sn level was negatively correlated with 8.26% (95% CI: 3.44-13.08%) decrease of high-density lipoprotein cholesterol (p < 0.001), and 71.2% of the joint effect attributed to Cd. Based on random forest, Se, Cd and Ni were found to be the dominant influencing factors of CHD. The role of Ni in CHD is yet to be uncovered, while excessive Cd exposure and low Se status among CHD patients need to be mitigated.