Trace Metal Concentrations Research Articles

Distribution of trace and rare earth elements in the estuary of Ría de Huelva (SW Spain): Field data and geochemical modeling

The geochemistry of the Ría de Huelva estuary (Spain) has been widely studied owing to its unique conditions due to mixing of acid mine drainage (AMD), river water and seawater, which have been aggravated by the existence of an adjacent phosphate fertilizer plant and its associated phosphogypsum stack.To better understand the complex geochemistry of the overall estuarine system, we make use of (1) measured concentrations of relevant trace elements (rare earth elements (REEs) and metal(loid)s) in the sediments and waters of the estuary and (2) geochemical modeling which combines mixing and adsorption processes.Our study sheds light on the elemental distribution in the sediments and water in the water-mixing area. As seawater neutralizes the acidity of the river water (pH increases to 6.2) colloids of Fe- and Al-oxyhydroxysulphates (schwertmannite and basaluminite, respectively) precipitate as concentrations of aqueous Fe and Al increase. These phases have a high adsorption capacity and play a critical role in the geochemistry of the aquatic system by retaining Cu, Pb, Cr, As, P, REEs and smaller amounts of Zn, Co, Ni and Mn. The geochemical model reproduces the behaviour of the aqueous REEs, requiring high S/L ratios at pH ≥ 3.5 and participation of sediments and colloids in the reactions to match the field data.The evaluation of the effect of the adjacent phosphogypsum stack on the estuarine geochemistry shows that the stack has a notorious impact on the geochemistry of the surrounding estuarine environment owing to the release of high quantities of phosphate.

Determination of trace and heavy metals in bottled drinking water in Yemen by ICP-MS

This study assessed the concentrations of several trace and heavy metals in bottled drinking water. A total of 27 samples were collected from Yemeni markets. The ICP-MS (inductively coupled plasma-mass spectrometry) technique was utilized to analyze the levels of Li, Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Se, Rb, Ag, Cd, Cs, Ba, Hg, Tl, Pb, and U. Furthermore, the study also examined the levels of total dissolved solids (TDS), electrical conductivity (EC), and pH in the collected samples. The concentrations of the elements in the bottled drinking water samples were compared to the maximum allowable concentration (MAC) values for these elements in drinking water, set by the World Health Organization (WHO) and Yemen’s Ministry of Water and Environment (YMWE). The limit of detection (LOD) and recovery ranged from 0.0003 to 1.86 μg/l, 80 to 120 %, respectively. Only trace elements Mn and Pb were detected in all samples at concentrations below the LOD. Out of the elements examined, only Hg exceeded the acceptable limits defined by both the WHO and YMWE in most of the samples.

Metal mobilization from thawing permafrost to aquatic ecosystems is driving rusting of Arctic streams

Climate change in the Arctic is altering watershed hydrologic processes and biogeochemistry. Here, we present an emergent threat to Arctic watersheds based on observations from 75 streams in Alaska’s Brooks Range that recently turned orange, reflecting increased loading of iron and toxic metals. Using remote sensing, we constrain the timing of stream discoloration to the last 10 years, a period of rapid warming and snowfall, suggesting impairment is likely due to permafrost thaw. Thawing permafrost can foster chemical weathering of minerals, microbial reduction of soil iron, and groundwater transport of metals to streams. Compared to clear reference streams, orange streams have lower pH, higher turbidity, and higher sulfate, iron, and trace metal concentrations, supporting sulfide mineral weathering as a primary mobilization process. Stream discoloration was associated with dramatic declines in macroinvertebrate diversity and fish abundance. These findings have considerable implications for drinking water supplies and subsistence fisheries in rural Alaska.

Potential of biochar and humic substances for phytoremediation of trace metals in oil sands process affected water

Oil sands process affected water (OSPW) is produced during bitumen extraction and typically contains high concentrations of trace metals. Constructed wetlands have emerged as a cost effective and green technology for the treatment of metals in wastewaters. Whether the addition of amendments to constructed wetlands can improve metal removal efficiency is unknown. We investigated the synergistic effects of carbon based amendments and wetland plant species in removal of arsenic, cadmium, cobalt, chromium, copper, nickel, and selenium from OSPW. Three native wetland species (Carex aquatilis, Juncus balticus, Scirpus validus) and two amendments (canola straw biochar, nano humus) were investigated in constructed wetland mesocosms over 60 days. Amendment effect on metal removal efficiency was not significant, while plant species effect was. Phytoremediation resulted in removal efficiencies of 78.61–96.31 % for arsenic, cadmium, and cobalt. Carex aquatilis had the highest removal efficiencies for all metals. Amendments alone performed well in removing some metals and were comparable to phytoremediation for cadmium, cobalt, copper, and nickel. Metals were primarily distributed in roots with negligible translocation to shoots. Our work provides insights into the role of plants and amendments during metal remediation and their complex interactions in constructed treatment wetlands.

Variation of trace metal minerals among different soil orders under different land use systems falling in Malwa region of Punjab in North-western India

BackgroundTrace metal deficiency has become a major constraint on the productivity and sustainability of soils. Agriculture becomes more complex, advanced and intensive farming systems develop, however, the deficiency of trace metal are more frequent and extensive in different systems. MethodsThis study investigated the variation of trace metal minerals in soil profiles of diverse land use systems (LUSs), i.e. agriculture, horticulture and forestry, falling under three dominant soil orders (Entisol, Inceptisol and Aridisol) in Malwa region of Punjab. Through comprehensive analyses, we explore the intricate relationships between soil characteristics, land use practices, and the distribution of key trace metals—namely zinc (Zn), copper (Cu), iron (Fe) and manganese (Mn). ResultsThe mean values of DTPA-extractable trace metal from soil profiles of different land uses varied from 1.75 to 2.09, 1.64–2.32, 1.18–1.69 mg kg−1 for Zn; 0.59–1.02, 0.59–0.99, 0.64–0.92 mg kg−1 for Cu; 12.12–16.49, 9.84–16.05, 7.94–11.56 mg kg−1 for Fe; 7.82–9.99, 4.66–9.39, 6.51–7.46 mg kg−1for Mn in soil orders Entisol, Inceptisol and Aridisol, respectively. The concentration of trace metals in different soil orders follows the pattern of ntisol>Inceptisol>Aridisol. In contrast, there is a considerable amount of variation and no discernible pattern in the distribution of trace metals under various LUSs in each soil order. Several LUSs were examined, and agriculture land use system (ALUS) had the greatest Fe and Mn content, while the horticulture land use system (HLUS) had the highest Zn and Cu content. The Irrespective of soil orders and LUSs, the concentration of trace metals decreased as soil depth increased. Diverse LUSs and management practices have a substantial impact on the physico-chemical characteristics of soils, which in turn influence the availability of trace metals. According to the Pearson correlation studies, trace metals were positively associated with soil OC and negatively associated with soil pH, electrical conductivity (EC), and calcium carbonate (CaCO3) and there was also a positive correlation between DTPA-Zn, Cu, Fe, and Mn in the investigated soils. The results of the principal component analysis (PCA) revealed that soil CaCO3 and organic carbon (OC) content were the most variable soil parameters influencing crop trace metal availability in different soil orders and land use systems. ConclusionThe findings contribute to a nuanced understanding of the dynamic interplay between soil properties and land use, providing valuable insights for sustainable agricultural practices and environmental management in the region.

Effect of domestic heat processing techniques on the trace metals concentration in imported frozen fish products in Bayelsa State, Nigeria, and health risk assessment

IntroductionTrace metals in fish play different important roles, both for the fish itself and humans who consume them. However, some of these metals are toxic at low concentrations, and are considered as health hazards. In this study, the concentration of six trace metals (Pb, Cd, Ni, Cu, Mn and Zn) were determined in imported frozen fish species available in Bayelsa State, Nigeria. The effect of domestic heat processing techniques (cooking, frying and smoking) on the trace metals concentration, and the potential risk due to consumption of these metals in fish were also evaluated. MethodsSix different species of imported frozen fish species were purchased from wholesale and retail outlets, and were prepared as raw, cooked, fried and smoked samples. A mixture of acids was used for digestion of fish samples, while Flame atomic absorption spectrometer was used for quantification of metals. The hazard index was employed for evaluating the non-carcinogenic risk of metals in fish. ResultsThe average trace metals concentration in the raw fish samples followed the order: Zn > Cu > Cd > Ni > Mn. Pb was undetected in all fish samples. The concentration of the detected trace metals ranged as follows - Cd: 3.45–9.40 mg/kg, Ni: <0.001–13.13 mg/kg, Cu: 6.10–9.95 mg/kg, Mn: <0.001–1.05 mg/kg, and Zn: 14.50–43.65 mg/kg. The Cd concentration in all raw fish species greatly exceeded its permissible limits. The effect of domestic heat processing techniques on trace metals concentration in fish did not follow any regular pattern, and only Cd concentrations exceeded its permissible limit in all heat processed fish samples. The hazard quotient (HQ) values showed that only Cd had HQ values >1 for both child and adult exposure scenarios. ConclusionThe results suggest trace metal contamination of fish samples by Cd, with significant potential non-carcinogenic risk. Since Cd is toxic, continuous screening of imported fish products is necessary, in order to safeguard public health.

Assessment of health risks from potassium bromate and trace metals in bread consumption in Ado Ekiti, Southwest, Nigeria

IntroductionBread, a staple food consumed by a large portion of the population worldwide, including Nigeria, has emerged as one of the most popular quick meal options. The excessive intake of potassium bromate and trace metals in bread has been identified as detrimental to human health due to its heightened propensity to induce cancer in human. ObjectiveThe current study assessed the exposure to potassium bromate (KBrO3) and trace metals through bread consumption, as well as the associated risks to dietary habits among Ado Ekiti, Southwest Nigeria residents. Bread varieties commonly consumed in Ado Ekiti were randomly chosen from local bakeries. These bread samples were then analyzed in the laboratory using an Atomic Absorption Spectrophotometer to determine the levels of trace metals, including lead (Pb), manganese (Mn), nickel (Ni), chromium (Cr), zinc (Zn), cadmium (Cd), and cobalt (Co), as well as potassium bromate concentrations. ResultsThe findings revealed that cobalt (Co) had the highest mean concentration (29.35±3.59 mg.kg−1), whereas lead (Pb) exhibited the lowest mean concentration (0.06±0.02 mg.kg−1). The sequence of trace metal levels was Co > Cd > Zn > Ni > Mn > Cr > Pb. All trace metal concentrations exceeded the standards set by FAO/WHO. Regarding potassium bromate content, it ranged from 0.01 mg.kg−1 to 0.06 mg.kg−1, surpassing the maximum permissible limits of 0.02 mg.kg−1 set by the Food and Drug Administration.Although the chronic hazard quotient among adults and children was low, the hazard ratio ranged from 11 to 9 among adults and from 14 to 9 among children, suggesting the potential for carcinogenic effects with repeated consumption. Based on the hazard ratios, the estimated chances of developing cancer from daily consumption of bread samples were approximately 14 in 1,000,000, 86 in 1,000,000, 71 in 1,000,000, and 40 in 1,000,000, respectively, for the adult population, and about 20 in 1,000,000, 11 in 1,000,000, 90 in 1,000,000, and 56 in 1,000,000 for the children population. ConclusionThe study showed that trace metals Pb, Mn, Ni, Cr, Zn, Cd and Co concentrations were higher than the FAO/WHO permissible limits. The concentration of potassium bromate in all the sorted bread samples exceeded the maximum acceptable limits except one. Though chronic hazard quotient among adults and children was low, the hazard ratio among the adult and children population was high, signifying possible cancer risks when continually consumed. These findings underscore the importance of stringent oversight by Nigerian regulatory authorities over using potassium bromate as an ingredient in bakeries.

Mapping soil trace metal distribution using remote sensing and multivariate analysis.

Trace metal soil contamination poses significant risks to human health and ecosystems, necessitating thorough investigation and management strategies. Researchers have increasingly utilized advanced techniques like remote sensing (RS), geographic information systems (GIS), geostatistical analysis, and multivariate analysis to address this issue. RS tools play a crucial role in collecting spectral data aiding in the analysis of trace metal distribution in soil. Spectroscopy offers an effective understanding of environmental contamination by analyzing trace metal distribution in soil. The spatial distribution of trace metals in soil has been a key focus of these studies, with factors influencing this distribution identified as soil type, pH levels, organic matter content, land use patterns, and concentrations of trace metals. While progress has been made, further research is needed to fully recognize the potential of integrated geospatial imaging spectroscopy and multivariate statistical analysis for assessing trace metal distribution in soils. Future directions include mapping multivariate results in GIS, identifying specific anthropogenic sources, analyzing temporal trends, and exploring alternative multivariate analysis tools. In conclusion, this review highlights the significance of integrated GIS and multivariate analysis in addressing trace metal contamination in soils, advocating for continued research to enhance assessment and management strategies.

Assessment of groundwater quality for drinking purposes of Malda District, India: Using WQI and GIS technique

AbstractWater, an essential life‐sustaining resource, holds global significance. Groundwater, a crucial component, provides substantial benefits to communities worldwide. This study focuses on evaluating the quality and suitability of groundwater for drinking purposes in the Malda district, employing methodologies that include the water quality index and geographic information systems. The data collected from West Bengal's groundwater yearbook for March 2020–2021 form the basis of this investigation. Following World Health Organization and Bureau of Indian Standards standard procedures, the study examines physicochemical characteristics and identifies hazardous elements such as potential of hydrogen, electrical conductivity, total hardness, Ca+, Na+, HCO3, F, Fe, SO4, K+, total dissolved solids, NO3, and Mg+. The findings reveal an alkaline nature in the groundwater of the Malda district, with dominant ions including HCO3−, F−, SO4−, and Cl−. Major cation chemistry is observed in Mg+, Ca+, and K+. Using the water quality index method, the results indicate 39% falling within the “excellent” category, 13% in “good” water quality, 34% considered “unsuitable,” 8% categorized as “poor,” and 4% falling into the “very poor” water quality bracket. The study's correlation and cluster analyses reveal complex relationships and distinct groupings among various parameters, emphasizing the need for comprehensive groundwater management. The study underscores the necessity for appropriate remediation measures to address high concentrations of trace metals in groundwater, posing potential health risks for domestic use. The incorporation of geographic information systems methodologies enhances the spatial understanding of these findings. This research contributes valuable insights for sustainable water resource management in the Malda district.

Comparing nitric acid treatment and microwave digestion for efficiency of metal extraction from bioprocess samples

Metal ions may act as enzyme cofactors and influence the kinetics of biochemical reactions that may also influence the biological production of therapeutic proteins and quality attributes such as glycosylation. Because sample preparation is a significant step in the reliable analysis of metals, we compared two sample preparation procedures for metal analysis of bioreactor culture media samples by ICP-MS: (i) samples were diluted in 2 % nitric acid (treatment with nitric acid, TNA); and (ii) samples were mixed with equal volume of 5 % nitric acid and closed vessel digestion was performed in a microwave (closed vessel digestion, CVD). In the comparison of extraction efficiencies between TNA and CVD procedures, CVD showed better extraction for Ca and Cu among bulk metals (∼30 %) and for Ni among the trace metals (∼65 %) for the bioreactor broth supernatant samples. For the cell pellet samples, the CVD procedure was found to be better for extraction of Fe (∼65 % more) among bulk metals, Zn (∼20 % more) among minor metals and Co (∼60 % more) and Ni (∼45 % more) among trace metals. Differences between the two procedures were less than 10 % and TNA was better for all other metals quantified from both supernatant samples and cell pellet samples. The current study helps bring more clarity to the methodology on comprehensive metal analysis to monitor and maintain trace metal content for biologics production.

Possible influence of shipping operations on trace metals gradients along the Commodore Channel, Lagos State, Nigeria

The impact of shipping operations on the level of trace metals along the Commodore Channel of the Lagos lagoon is a topic that requires careful consideration. Shipping activities can have a significant impact on the water quality of the lagoon, which in turn can affect the health of the flora and fauna that depend on it. This study attempts to assess the impact of shipping operations on the level of trace metals along the Commodore Channel of the Lagos lagoon. Concentrations of trace metals in the Lagos Lagoon specifically the Commodore channel were determined in March 2016, and the downstream variation was compared. Trace metals (Pb, Cd, Fe, Zn and Co) were determined using Atomic Absorption Spectroscopy (AAS). The concentration of trace metals were found to be beyond the permissible limits stipulated by World Health Organization (WHO) and European Union (EU). There exists an exception in the mean level of Zn (0.23±0.1107mg/L) in the harbor water which was lower than the WHO standard of 5mg/L as at the time of this study. The trace metals showed the decreasing order of Pb &gt; Fe &gt; Zn &gt; Co &gt; Cd with concentration of 1.0±0.6mg/L, 0.62±0.2mg/L. 0.23±0.1107, 0.14±0.12mg/L and 0.05±0.02mg/L respectively. The result of contamination factor showed the harbor water had very high degree of Pb and Cd contamination. This high CF can be caused by the shipping and vessel transportation route and gateway of the harbor into the country. Continuous monitoring is required to assess environmental quality and adopt suitable management techniques in order to prevent the negative impacts of shipping operations on trace metal occurrence in harbors.

Impact of air quality on the health of present-day workers in an Asbestos roof manufacturing industry, Sri Lanka.

The study's objective was to determine the air quality in an asbestos-related industry and its impact on current workers' respiratory health. Seventy-seven air and 65 dust samples were collected at 5-day intervals in an asbestos roofing sheets production factory in Sri Lanka having two production facilities. Sampling was performed in ten sites: Defective sheets-storage, Production-plant, Pulverizer, Cement-silo, and Loading-area. A detailed questionnaire and medical screening were conducted on 264 workers, including Lung Function Tests (LFT) and chest X-rays. Asbestos fibres were observed in deposited dust samples collected from seven sites. Free chrysotile fibres were absent in the breathing air samples. Scanning Electron Microscopy confirmed the presence of asbestos fibres, and the Energy Dispersive X-ray analysis revealed Mg, O, and Si in depositions. The average concentrations of trace metals were Cd-2.74, Pb-17.18, Ni-46.68, Cr-81.01, As-7.12, Co-6.77, and Cu-43.04mg/kg. The average Zn, Al, Mg, and Fe concentrations were within 0.2-163g/kg. The highest concentrations of PM2.52.5 and PM1010, 258 and 387µg/m3, respectively, were observed in the Pulverizer site. Forty-four workers had respiratory symptoms, 64 presented LFT abnormalities, 5 indicated chest irregularities, 35.98% were smokers, and 37.5% of workers with abnormal LFT results were smokers. The correlation coefficients between LFT results and work duration with respiratory symptoms and work duration and chest X-ray results were 0.022 and 0.011, respectively. In conclusion, most pulmonary disorders observed cannot directly correlate to Asbestos exposure due to negligible fibres in breathing air, but fibres in the depositions and dust can influence the pulmonary health of the employees.

Paleoceanographic Significance of Calcareous Nannofossil Assemblages in the Tropic Shale of Utah during Oceanic Anoxic Event 2 at the Cenomanian/Turonian Boundary

Oceanic Anoxic Event 2 (OAE2) at the Cenomanian/Turonian Boundary (CTB: 93.9Ma) involved the global deposition of organic carbon-rich sediments, a distinctive positive shift in carbon isotope values, and significant species turnover, including changes in calcareous nannofossil assemblages. While it is thought that volcanism triggered organic C-rich sediment deposition during OAE2, it is unclear whether enhanced productivity, increased stratification, of some combination of the two increased organic matter preservation. Calcareous nannofossil assemblages have the potential to qualitatively assess changes in ocean nutrient and temperature conditions to disentangle such ecological dynamics during OAE2. Here we study an expanded section of the Tropic Shale in a drill core in southern Utah near the western margin of the Western Interior Seaway (WIS) to understand how circulation changed during the event and how this may have influenced primary productivity and organic carbon burial. Relative abundance data of well-preserved nannoplankton are complemented with measurements of trace metal, and organic carbon and carbonate concentrations to determine changes in temperature and water column structure, as well as controls on surface water productivity. Detailed statistical analysis helps refine species paleoecologies combined with information from planktic and benthic foraminiferal assemblages and organic biomarkers. Changes in calcareous nannofossil assemblages indicate that near the start of OAE2 the western WIS surface ocean actually cooled for a short time. Following this, surface waters became warmer and more stratified as a Tethyan water mass invaded the seaway. Assemblages suggest that warmth persisted for much of the OAE2 interval, while stratification waxed and waned. The local seaway cooled near the end of OAE2 as Boreal water masses streamed along the western margin. Variations, including the decrease in the abundance of Biscutum constans and short-lived peaks in the abundance of Eprolithus spp. are super regional or possibly global in extent. There is no correlation between calcareous nannofossil assemblages and trace metal concentrations, suggesting they were unaffected by volcanism-related nutrient inputs. Assemblages support other data that suggest increased stratification influenced organic carbon burial in the Western Interior Seaway, and possibly elsewhere, during OAE2.

Assessment of hydrochemical characteristics and trace metals of Punpun River water – a tributary of the Ganga River

ABSTRACT This manuscript presents the first inventory of dissolved ions (cations and anions) and trace metals (Pb, Mn, Cr, Co, Ni, Cu and Zn) in the Punpun River water to assess its irrigational suitability, pollution sources and hydrogeochemical processes. For this, the physicochemical parameters and trace metals in river water were analysed in the pre- and post-monsoon seasons. The results showed that the concentrations of cations and anions were Ca2+ &amp;gt; Na+ &amp;gt; Mg2+ &amp;gt; K+ and HCO3− &amp;gt; SO42- &amp;gt; Cl− &amp;gt; NO3− &amp;gt; PO43-, respectively, in both the pre- and post-monsoon seasons. However, trace metal concentration in pre- and post-monsoon followed the trend of Pb &amp;gt; Mn &amp;gt; Cr &amp;gt; Ni &amp;gt; Cu &amp;gt; Zn &amp;gt; Co and Pb &amp;gt; Ni &amp;gt; Mn &amp;gt; Cr &amp;gt; Zn &amp;gt; Co &amp;gt; Cu, respectively. The results reveal that combined effects of rock weathering and evaporation-concentration influence hydrochemistry, along with anthropogenic factors like industrial effluents, urban domestic sewage and agricultural runoff. Piper and Durov plots suggest that the river water is dominated by Ca–Mg–HCO3− type, and the processes were governed by simple ion dissolution and mixing. However, the Gibbs plot shows that silicate and carbonate weathering govern the hydrochemical properties. Irrigational indices like sodium adsorption ratio, %Na, residual sodium carbonate, Kelly's ratio, magnesium hazard, and trace metals indicate that most of the water samples are suitable for irrigation. Comprehensive pollution index values suggest that the river water quality ranges from sub-clean to slightly to moderately polluted.

Assessment of Societal Health Risks: Spatial Distribution and Potential Hazards of Toxic Metals in Street Dust Across Diverse Communities

On a global scale, the urban design of city centers is a topic of discussion concerning various aspects such development and its impact on public health. This research examines the health effects of urban agglomeration in city centers with compact, close development. In this work, the potentially toxic metals in street dust were studied by collecting and measuring street dust samples, measuring trace metal concentrations, and using index assessment, spatial analysis, correlation analysis, and health risk assessment models. Eskişehir, located in the part of Central Anatolia close to the Aegean region, west Türkiye, has been widely recognized as one of the most popular, known for having many narrow and old buildings in urban environments. The present paper investigates the atmospheric dust-related chemical speciation, urban environmental pollution, and human health risks in Eskişehir City by studying 66 dust samples collected at 11 points in the selected streets in August 2023. the study found that the concentrations of trace elements followed the order Cr > Ni > Pb > Cd > Cu. The primary source of these high levels is believed to be traffic-related contamination involving Cd, Pb, and Ni. The assessment of non-carcinogenic health risks has shown that the significant sources of potential toxic metals exposure for both children and adults are i) through ingestion and ii) dermal contact. The Hazard index (HI) for selected metals decreased in the order Cr > Pb > Ni > Cd > Cu for both children and adults without imposing possible non-carcinogenic risk (HI<1). On the contrary, Cr posed cancer risks above the safety threshold (> 10-4) through ingestion. Based on the available findings, Eskişehir still suffers from considerable environmental and ecological degradation and severe health risks due to street dust contamination. However, while high pollution was detected in the city center, where there is commercial land use, low values were observed in the region, rich with the water surface, bicycle paths, landscape design, and where traffic is slowed down.

Biomarkers of oxidative stress and bioaccumulation of trace metals in waterbirds from different rice fields systems

AbstractWe compared trace metal concentrations (Pb, Zn, Cd, Cu) in feathers and biomarkers in muscle and liver tissue of waterbirds from organic and conventional irrigated rice farms in South Brazil. Cu and Pb concentrations were higher in waterbirds from conventional farms, whereas Cd and Zn levels were elevated in organic farms. Birds foraging in organic farms exhibited lower CAT and SOD activity and higher NPSH, LPO, and PC concentrations compared to those in conventional farms. Higher Cu and Pb concentrations were associated with elevated SOD and CAT activity, more prevalent in birds frequenting conventional farms. Conversely, birds with higher Cd and Zn concentrations showed increased NPSH, LPO, and PC levels and were more common in organic farms. Our study underscores complex differences in trace metal accumulation and oxidative stress biomarkers among waterbirds in organic and conventional rice crops.

Influence of the Atlantic inflow on trace metal enrichments in sediments and particulate matter of the NW Alboran Sea (SW Mediterranean)

Trace metal contents and fluxes in downward particulate matter and dated sediment cores of the NW Alboran Sea are analysed in this study with the aim of assessing the role of the Atlantic inflow on their transport. Increases in Zn, Cu and Pb were detected in downward particulate matter collected by sediment traps after river flooding events and after the Aznalcollar mining spill. Their arrival coincided within the recently estimated time range for river particles discharged into the Gulf of Cádiz to reach the Alboran Sea, indicating that their transfer is enhanced during events of increased river inputs of contaminated particulate matter. This also suggests that the effects of potential tailing dam failures in the Gulf of Cádiz watersheds could reach the Alboran Sea. These trace metals also increased in the sediment cores from the continental rise since the second half of the 19th century, suggesting that contaminated particles have been continuously transferred towards the Mediterranean Sea since that time, when mining concessions and production increased in the SW Iberian Pyrite Belt.

Biogeochemistry of dissolved trace metals in the Bay of Bengal

The pronounced seasonal variation over the Bay of Bengal affects trace metals concentration and distribution. Trace metals distribution in the Bay of Bengal has been best characterized during spring and fall intermonsoon, while limited studies were conducted during the southwest monsoon. This study reports the full-depth profiles of trace metals, including dissolved iron, manganese, lead, cadmium, copper, and zinc (Fe, Mn, Pb, Cd, Cu, and Zn) in the Bay of Bengal (BoB) during southwest monsoon, from July to August 2013. At coastal and ocean scales, transect observations covering the entire water depth provided a comprehensive picture of the circulation and biogeochemical cycles of these elements in seawater during the southwest monsoon. Water samples were obtained from one station in the northeastern Indian Ocean (NR-1) and from three shallow coastal stations with maximum depths <60 m (BA-1, BA-3, and BA-5), as well as from three offshore stations with maximum depths exceeding 2000 m (MY-7, MY-9, and MY-11). In the surface layer (5 m depth), the trace metal concentrations at the shallow near-coastal station BA-5 were higher than those at the ocean station NR-1. Surface trace metal concentrations in offshore regions encompassing stations MY-11, MY-9, and MY-7 were relatively higher than those reported for other seasons in a similar salinity region, indicating seasonal variation associated with freshwater intrusion and coastal-derived input. Below the mixed layer depth, the trace metal/phosphate (P) ratio was higher than that previously reported in the eastern Indian Ocean, suggesting an input from continental margins and mildly reducing sediments, particularly for Fe, Mn, and Cu. Moreover, at intermediate depths (190–800 m), where the North Indian Central Water (NICW) is the main water mass, the Cd/P ratio (0.55 ± 0.11 nmol/μmol) deviated from the global trend (∼0.3 nmol/μmol) owing to oxygen-deficient conditions. Intriguingly, at some stations, specifically MY-9 and MY-7, the intermediate dFe concentrations were relatively higher than those at station NR-1 at the same depth. Continental margin sediment, water mass movement, and ventilation may control the transport of Fe from locations with high Fe concentrations, including near the continental shelf (station MY-11 in this study) and the Andaman Sea.

Assessment and Evaluation of Atmospheric Trace Metals Pollution in Lapai Metropolis, Niger State Using Foliose Epiphytic Lichen (Parmelia sulcata)

The levels of atmospheric trace metals were determined using foliose epiphytic lichens (Parmelia sulcata) samples collected in eight (8) different locations within the residential areas and two control locations outside the residential area of Lapai town in Lapai local government of Niger State. A stratified random sampling technique was adopted and the analysis of the samples with atomic absorption spectrophotometer (AAS) gives the concentration range of the metals as follows; 1.123-7.837 mg/kg for Fe, 4.579-6.627 mg/kg for Pb, 0.210-2.152 mg/kg for Cr, 0.491-1.171 mg/kg for Ni, 0.018-0.983 mg/kg for Cd, 0.057-1.471 mg/kg Zn, 0.198-1.287 mg/kg for Mn, and 0.098-2.583 mg/kg for Cu but Selenium was not detected in all the samples. The levels of some of these metals were slightly higher compared to recommend USEPA (1993) limits but lower than FEPA (1991) limits. However, the distribution of these metals was not uniform across the samples, though their level was still at the background and very low compared to the reports on similar studies from industrialized areas of South-south and South-west Nigeria and other European countries. The variation in concentration of these metals at P≤0.05 indicates their source is mainly anthropogenic in origin. Epiphytic lichens validate the cost-effectiveness of this method for evaluating, assessing, and identifying depositional sources of the metals in the environment. The study revealed the atmospheric trace metal concentration of the area under study to be at a threshold level and hence the environment is still very safe from atmospheric trace metal pollution.

Nutritional composition and mineral bioavailability of selected root and tuber crops in the Bicol Region, Philippines

Filipinos consume root and tuber crops as inexpensive sources of nourishment. However, the limited information on the nutritional and mineral bioavailability of root and tuber crops inhibits their optimal utilization in what could possibly address nutrient deficiencies among the populations. This study determined the proximate composition of cassava, sweet potato, taro, giant swamp taro, cocoyam, and purple yam through the Association of the Analytical Chemists (AOAC) standard method. The mineral bioavailability was determined in vitro by simulating digestion from the oral up to the intestinal phase. Mineral and trace metal contents were quantified using a Microwave Plasma Atomic Emission Spectrometer (MP-AES). The crops’ ash, protein, fat, and total dietary fiber contents ranged from 1.23-3.53%, 2.01-9.32%, 0.18-0.83%, and 4.23-19.3%, respectively. Taro (9.32%) and purple yam (6.71%) have the highest protein contents among the crops examined and can be considered as sources of protein based on the recommended nutrient intake (RENI) for Filipino adults. Except for cassava, most of the studied crops were high sources of total dietary fiber, with the giant swamp taro (48% RENI) as the highest. Total minerals such as K, Ca, Mg, Na, and considerable quantities of Zn, Mn, Fe, and Cu were detected. The mineral bioavailability varied for Zn (47.0-98.0%), Cu (37.5-86.8%), Mn (31.5-91.8%), Mg (31.9-90.2%), Ca (2.54-31.1%) and Fe (4.7-20.7%). Consumption of 100 g of the examined crops, except for giant swamp taro and cassava, can contribute to the daily Cu for adults aged 19-29. Taro contributes to the daily nutritional requirement for bioavailable Ca and Mg, while giant swamp taro contributes to Zn and Mn requirements. None of the examined crops contained sufficient bioavailable Fe to contribute to Filipinos’ daily requirements. The study can help address the limited information on the nutritional and mineral bioavailability of root and tuber crops, which hampers their utilization to address some nutrient deficiency among the Filipino population, and emphasizes the consumption of these crops to enhance dietary diversification, which can alleviate some nutrient deficiencies in the country.