Non-essential Elements Research Articles

A preliminary study of metal accumulation in fish from Cimanuk and Cimandiri, West Java, Indonesia

Fish is known to be a source of animal protein consisting of low cholesterol and non fatty acid. It also promotes sustainable consumption in coastal communities. Metal contamination in aquatic bodies, particularly rivers and oceans, is made more likely by anthropogenic factors. Metal may accumulate in fish as a result of the food web, posing a health risk to humans. Metal contamination in ingested fish should be monitored as part of risk mitigation. The goal of this research was to investigate six elements (Cr, Cu, Se, Pb, Cd, and As) in the edible tissues of fish from Cimanuk and Cimandiri, West Java. Karangsong and Palabuhan Ratu were two locus of fishing ports in Cimanuk and Cimandiri, respectively. In April of 2017, commercial demersal fish were obtained. Three fish from Palabuhan ratu and four fish from Karangsong were captured. Metal analysis was conducted using Inductively Coupled Plasma-Optical Emission Spectrometry (ICP OES). The results revealed that the non-essential elements such as cadmium (Cd) and arsenic (As) had exceeded the permissible limits of the BPOM. Practically, organic arsenic (arsenobetain) is the most common arsenic found in fish (90-95%), and relatively safe compared to inorganic arsenic. Indications of Cd enrichment can come from anthropogenic factors and reinforce the necessity for environmental monitoring of habitats around fishing areas. Essential metals like selenium, copper, and chromium are maintained at a certain concentration based on metabolic activity and vary according to fish body homeostasis.

Risk and benefit assessment of seafood consumption harvested from the Pertuis Charentais region of France

Seafood is well recognized as a major source of Long Chain n-3 Polyunsaturated Fatty Acids (LC n-3 PUFA, especially ecosapentaenoic acid, i.e. EPA and docosaheaxaenoic acid, i.e. DHA) and essential trace elements (As, Cu, Fe, Mn, Se, and Zn). It is also a source of non-essential trace elements (Ag, Cd, Hg, Pb) that can be deleterious for health even at low concentrations. Edible parts of sixteen species (fish, cephalopods, crustaceans and bivalves) of great importance in the Pertuis Charentais region, one of the main shellfish farming and fishing areas along the french coastline, were sampled in winter and analyzed to determine their fatty acid (FA) composition and trace element concentrations. Based on these analyses, a suite of indices was calculated to estimate risk and benefit of seafood consumption: the n-6/n-3 ratio, the atherogenic index, the thrombogenic index, the EPA + DHA daily recommended portion, as well as the maximum safe consumption. The results showed that fish contributed the most to LC n-3 PUFA supply, while bivalves and crustaceans were more beneficial in essential trace elements. Whatever the species, the concentrations of non-essential elements were not limiting for seafood consumption, as important amounts of the analyzed species can be eaten daily or weekly before becoming hazardous to consumers. Yet, concentrations of Hg in dogfish and seabass can become a concern for frequent seafood consumers (>three meals a week), confirming that varying seafood items is a key point for consumers to optimize the benefits of diverse seafood resources. Considering FA composition, whiting and pilchard are the most beneficial fish species for human diet, while surmullet was the least beneficial one. However, using an index integrating the relative risk due to Hg content, the surmullet appears as one of the most beneficial. This study provides a temporal shot of the quality of marine resources consumed in winter period in the studied area and highlights the complexity of a quantitative risk and benefit assessment with respect to the biochemical attributes of selected seafood.

Comparison of the Mineral and Nutraceutical Profiles of Elephant Garlic (Allium ampeloprasum L.) Grown in Organic and Conventional Fields of Valdichiana, a Traditional Cultivation Area of Tuscany, Italy.

Simple SummaryIn Valdichiana, an agricultural area of Tuscany (C Italy), an antique landrace of elephant garlic (A. ampeloprasum L.) locally known as “Aglione della Valdichiana” has been cultivated for a long time, and has been recently recognized as a traditional agri-food product of Tuscany and of Italy. Two methods of cultivation of elephant garlic are currently in use in Valdichiana: conventional and organic, the latter not making use of mineral fertilizers and chemical pesticides, even if the cultivation of elephant garlic is a low impact one. This paper aimed at testing if there are differences in the mineral and nutraceutical profiles of elephant garlic cultivated conventionally and organically in the Valdichiana area. Our results indicated only small differences and no evidence of healthier food or superior nutraceutical quality for organically grown elephant garlic.In the Valdichiana area (Tuscany, Italy) an ancient native landrace of elephant garlic (Allium ampeloprasum L.), locally known as “Aglione della Valdichiana”, has long been cultivated. The aim of this study was to check whether there are differences in the mineral and nutraceutical profiles of the Aglione della Valdichiana cultivated conventionally and organically. Based on the analysis by ICP-MS of a wide array of major, minor, essential, and non-essential trace elements as well as rare earth elements, and the evaluation of the content of polyphenols, flavonoids, antioxidants, soluble proteins, soluble sugars, and starch, as well as the weight and water content, it was concluded that differences in the mineral and nutraceutical profiles of organically and conventionally grown bulbs were very limited. Only a statistically (p < 0.05) higher concentration of Cd (+2620%), Co (+113%), Mn (+55%), Rb (+180%), and Sb (+180%), as well as glucose (+37%) in conventionally cultivated bulbs emerged. Cadmium was the only element slightly higher than in the “reference plant,” but with a negligible risk (three orders of magnitude lower) for human health based on consumption. It is concluded that we failed to find evidence of healthier food or a higher nutraceutical quality for organically cultivated elephant garlic.

Concentration and Distribution of Cu, Zn, Pb, and Cd in Mackerel Icefish (Champsocephalus gunnari) in South Georgia, Antarctic, During Winter.

Knowledge of the essential and nonessential elements distribution and behavior in Antarctic fish is important for understanding the essentiality and requirements of minerals in the diet of those species, as well as the bioavailability and storage of trace minerals in the tissues of fishes. In this study, the levels of zinc, copper, cadmium, and lead in muscle, intestine, liver, gill, and skin of mackerel icefish Champsocephalus gunnari (Lönnberg, 1905) in South Georgia were determined during winter. The following element concentration ranking was recorded: Zn > Cu > Cd > Pb in the muscle, Zn > Cu > Cd > Pb in the skin, Zn > Cu > Cd > Pb in the intestine, Zn > Cu > Pb > Cd in liver, and Zn > Cu > Cd > Pb in the gill. The concentration of Zn is higher by about two orders of magnitude than that of the other three elements for the tissues. Generally, apart from Cu levels in the liver and Cd levels in the intestine, the correlation of elements in tissues with both size and weight of C. gunnari is not observed. The levels of elements were compared to those reported for C. gunnari in the Kerguelen waters.

Calcium-permeable cation channels are involved in uranium uptake in Arabidopsis thaliana

Uranium (U) is a non-essential and toxic element that is taken up by plants from the environment. The assimilation pathway of U is still unknown in plants. In this study, we provide several evidences that U is taken up by the roots of Arabidopsis thaliana through Ca2+-permeable cation channels. First, we showed that deprivation of Arabidopsis plants with calcium induces a 1.5-fold increase in the capacity of roots to accumulate U, suggesting that calcium deficiency promotes the radionuclide import pathway. Second, we showed that external calcium inhibits U accumulation in roots, suggesting a common route for the uptake of both cations. Third, we found that gadolinium, nifedipine and verapamil inhibit the absorption of U, suggesting that different types of Ca2+-permeable channels serve as a route for U uptake. Last, we showed that U bioaccumulation in Arabidopsis mutants deficient for the Ca2+-permeable channels MCA1 and ANN1 is decreased by 40%. This suggests that MCA1 and ANN1 contribute to the absorption of U in different zones and cell layers of the root. Together, our results describe for the first time the involvement of Ca2+-permeable cation channels in the cellular uptake of U.

Per- and polyfluoroalkyl substances (PFAS), trace elements and life history parameters of mass-stranded common dolphins (Delphinus delphis) in New Zealand

Profiles of 33 PFAS analytes and 12 essential and non-essential trace elements were measured in livers of stranded common dolphins (Delphinus delphis) from New Zealand. PFAS concentrations reported were largely comparable to those measured in other marine mammal species globally and composed mostly of long-chain compounds including perfluorooctanesulfonic acid (PFOS), perfluorododecanoic acid (PFDoDA), perfluorotridecanoic acid (PFTrDA) and perfluorooctanesulfonamide (FOSA). PFAS profiles did not vary significantly by location, body condition, or life history. Notably, significant positive correlations were observed within respective PFAS and trace elements. However, only negative correlations were evident between these two contaminant types, suggesting different exposure and metabolic pathways. Age-associated concentrations were found for PFTrDA and four trace elements, i.e. silver, mercury, cadmium, selenium, indicating differences in the bioaccumulation biomagnification mechanisms. Overall, our results contribute to global understanding of accumulation of PFAS by offering first insights of PFAS exposure in cetaceans living within South Pacific Australasian waters.

Trace elements (Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) in Mytilus galloprovincialis and Tapes decussatus from Faro and Ganzirri Lakes (Sicily, Italy): Flow cytometry applied for hemocytes analysis

BackgroundTrace elements present in sessile molluscs, are important because they are used in human consumption and it has significantly increased in recent years. While their filtering of the water can lead to their build-up of organic and inorganic materials that can be sampled and analyzed, this can also lead to bioaccumulation of harmful substances, such as essential and non-essential elements, that can harm the human health if in taken in high concentrations or for a long period of time. MethodsIn the present study, the trace metal content (Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) of two sessile crustaceans, 20 Mytilus galloprovincialis (mussel) and 20 Tapes decussatus (clam) in Faro and Ganzirri Lakes (Messina, Sicily, Italy) were analyzed. Haemolymph samples were taken on both molluscs in order to analyze the haemocyte population by flow cytometric analysis. Unpaired t-tests were used to determine significant differences for the essential and non-essential metallic elements concentrations in the lake waters and in the tissues of M. galloprovincialis and T. decussatus and for hemocyte populations R1 (halinocytes) and R2 (granulocytes). ResultsThe results suggested that that in Faro Lake, the tissue Al, Cr and Pb levels in M. galloprovincialis were higher than those for T. decussatus, in contrast to Mn, Fe, Ni, Cu, Zn and Cd, which were higher in T. decussatus. Unpaired t-tests showed that there were significantly higher proportions of halinocytes in M. galloprovincialis versus T. decussatus for both Faro Lake (41.8 % vs. 24.3 %; P < 0.001) and Ganzirri Lake (43.0 % vs. 22.4 %; P < 0.001). In contrast, while there were significantly higher proportions of granulocytes in Faro Lake (21.2 % vs. 9.1 %; P < 0.001), this difference was not seen for the granulocytes of M. galloprovincialis versus T. decussatus in Ganzirri Lake (9.6 % vs. 13.0 %). ConclusionThis study shows that M. galloprovincialis and T. decussatus can indeed bioaccumulate some of these metal, such that activation of the immune responses is specific to certain cell types. Future research must focus on the balance of trace elements in the consumption of these shellfish, and analyzes with more sophisticated tools can be used to diagnose the increased concentration of trace elements and the quantification of trace metals from shellfish to clams.

Similarities and differences of potentially toxic elements contents in leaves of Fraxinus excelsior L. and Platanus orientalis L. in an urban environment

The recognition of the features and capabilities of potentially toxic elements (PTE) uptake from urban tree leaves is crucial for mitigating pollution and optimizing the allocation of green infrastructures of an urban environment. Therefore, Pb, Ni, Mo, Cu, Zn contents and spatiotemporal variation were investigated in the leaves of the most widespread urban trees in Yerevan (Armenia) (Fraxinus excelsior L. and Platanus orientalis L.) by means of a chemical approach based on atomic-absorption spectroscopy, after having washed them. The obtained results showed similarities in leaves Ni, Cu, Pb and Mo uptake. Meanwhile, only biologically non-essential elements (Mo and Pb) tend to accumulate in leaves during the vegetation season. This allows for the identification of localized pollution sources. Spatiotemporal variation of Zn contents suggested that P. orientalis L. is the less efficient tree species in Zn uptake. The study of the relationship of Pb, Ni, Mo, Cu, and land use by means of clr-biplots showed the absence of any potential links. Moreover, it was revealed that the element contents of leaves in green areas are similar to those observed in industrial and residential sites. The latter highlighted the need for the expansion of green areas with the use of scientifically justified species as a means of nature-based solution for pollution mitigation and better urban environmental management.

Change in cotton plant quality in response to application of anaerobically digested sewage sludge

Treated municipal sewage sludge (TSS) was applied to the cotton plant at rates of 10, 20 and 30 t/ha per year. Seed cotton yield (71.4%), lint yield (67.7%) and cottonseed yield (74.1%) were increased significantly when sludge was applied at a rate of 30 t/ha (TSS3). The effects of TSS applications on seed yield, lint yield and cottonseed yield were listed as TSS3 > TSS2 > CF > TSS1 > C according to the applications. The increasing TSS levels had a positive effect and increased the total N concentration compared to the control. The highest N value was observed in TSS3 plots, while the lowest value was recorded in control (C) plots. The highest P value was found in control (C) at 0.80% and in 10 t/ha (TSS1) at 0.80%, while the lowest value was found in the TSS2 application (0.70%). The K concentration of cottonseed increased with the increasing TSS rates, from 1.56% in control plots to 2.20% in 20 t/ha application (TSS2). Corresponding to the TSS levels, the calcium of plant tissues was determined by a range of 0.12–0.13%. The treatments of TSS and mineral fertilizer had similar effects on the Mg content of cottonseed, which was in the range of 0.38–0.43%. Na content in plant tissue increased with increasing dose of sludge application compared to control soils. Increasing doses of TSS had no significant effect on the concentrations of iron (Fe), copper (Cu), zinc (Zn), manganese (Mn) and boron (B) in cottonseed. The order of the elements with respect to their amounts in cottonseed was as follows: Fe > Zn > Na > B > Mn > Cu. The concentrations of non-essential elements (Ni, Cd, Cr, Pb, Hg and As) in cottonseed were below the permissible limits.

Cadmium interference with iron sensing reveals transcriptional programs sensitive and insensitive to reactive oxygen species

Iron (Fe) is an essential micronutrient whose uptake is tightly regulated to prevent either deficiency or toxicity. Cadmium (Cd) is a non-essential element that induces both Fe deficiency and toxicity; however, the mechanisms behind these Fe/Cd-induced responses are still elusive. Here we explored Cd- and Fe-associated responses in wild-type Arabidopsis and in a mutant that overaccumulates Fe (opt3-2). Gene expression profiling revealed a large overlap between transcripts induced by Fe deficiency and Cd exposure. Interestingly, the use of opt3-2 allowed us to identify additional gene clusters originally induced by Cd in the wild type but repressed in the opt3-2 background. Based on the high levels of H2O2 found in opt3-2, we propose a model where reactive oxygen species prevent the induction of genes that are induced in the wild type by either Fe deficiency or Cd. Interestingly, a defined cluster of Fe-responsive genes was found to be insensitive to this negative feedback, suggesting that their induction by Cd is more likely to be the result of an impaired Fe sensing. Overall, our data suggest that Fe deficiency responses are governed by multiple inputs and that a hierarchical regulation of Fe homeostasis prevents the induction of specific networks when Fe and H2O2 levels are elevated.

Harvest index and remobilization of 13 elements during wheat grain filling: Experiences from ozone experiments in China and Sweden

• Nutrient elements generally have higher harvest index (HI) than non-essentials elements. • Element HI is strongly element specific. • Ozone significantly reduces HI for nutrient elements and Cd. • No ozone effect on total aboveground element pool, except for P. Wheat efficiently remobilize and allocate a large fraction of aboveground biomass and nutrients into their grains during maturation. This senescence process has been streamlined through crop breeding, which lead to increasing harvest index (HI) for biomass. With field data from two ozone exposure experiments, we derived HI for 13 elements, both nutrients and non-essential, to determine how efficiently they are allocated into the wheat grain in two different agro-ecological environments (Sweden and China) and under different ozone exposure regimes. Element HI ranged from 10 to 90 %, with highest rates for P, N and Zn (90 %, 80 % and 70 %, respectively), while HI was low for the non-mobile elements Ba, Sr and Ca (<10 %). HI for biomass was about 50 %, and the non-essential and toxic element Cd was in the same range (∼40 %). Overall element HI was very similar in Chinese and Swedish wheat cultivars. This was also the case when comparing the two Chinese genotypes. We conclude that element HI for wheat crops are highly element specific and not strongly dependent on site or cultivar. Ozone exposure significantly reduced HI for both macronutrients (Ca, K, Mg, N, P) and micronutrients (Cu, Mn, Mo, Zn), but also for Cd, while there was no ozone effect on the total aboveground pool for any element except P and Ba. Consequently, the reduction in grain element yield induced by elevated ozone, observed in previous studies, can be explained by lower remobilization rates rather than reduced total uptake. Our results provide new insights of nutrient use efficiency in wheat crops in general and under ozone exposure, which can be implemented in crop modelling and also useful for breeding strategies aiming to improve the nutritional value of food crops.

Potential elemental exposure and health risk associated with the consumption of groundnut paste processed with local milling machines within the Kumasi metropolis

This study sought to determine the influence of commercial milling machines on metal contamination of locally produced groundnut paste, and the potential risk associated with consumption. A total of 30 composite groundnut samples were collected from 9 markets within the Kumasi Metropolis and 1 nearby district market. Metal content was determined with X-ray Florescence Technique, which allowed scanning for 25 elements from Sulphur to uranium as stated on the ThermoFisher Scientific website [45]. The samples contained essential elements; Molybdenum, Zinc, Iron, Calcium and Potassium with mean concentrations of 4.64±0.58 mg/kg, 25.24±1.94 mg/kg, 486.44±333.42 mg/kg, 2023.26±485.98 mg/kg and 22,867.25±5309.73 mg/kg respectively, and non-essential elements; Niobium, Zirconium, Strontium, Titanium and Rubidium with mean concentrations of 3.36±0.66 mg/kg, 3.30±0.46 mg/kg, 6.01±1.19 mg/kg, 64.27±18.04 mg/kg and 6.71±1.24 mg/kg respectively. When compared to control samples processed using porcelain pestle and mortar, results suggest an increase in metal concentration due to the milling process. Health risk assessment indicated no likely health hazard. Metals such as Chromium, Nickel, Cadmium and Lead were not detected.

A State-of-the-Science Review on Metal Biomarkers Used in Epidemiological Mixtures Analyses: Best Practices and Common Pitfalls

BACKGROUND AND AIM: Researchers are increasingly using innovative statistical methods to understand how exposure to real-world metal mixtures may affect human health. Although these new statistical approaches, such as Bayesian Kernel Machine Regression and Weighted Quantile Sums Regression, allow for researchers to include a wide panel of metals in their analysis, metals have unique sources and routes of exposure, different adsorption and elimination pathways and not all biomarkers are effective measures of exposure. This review aims to move the field of metal epidemiology forward by summarizing the most up-to-date research available on several metals, particularly highlighting the strengths and limitations of metal biomarkers and discussing potential existing evidence of interactions with other metals and environmental exposures. METHODS: We reviewed observational and experimental studies from database searches and citations regarding exposure to 12 different metals, including 8 non-essential elements (arsenic, barium, cadmium, lead, mercury, nickel, tin, uranium) and 4 essential trace elements (manganese, molybdenum, selenium, and zinc). We included more than 500 studies. RESULTS:In this review, we discuss in depth major environmental sources of exposure, biotransformation and elimination, biomarkers of exposure, and known interactions with other metals and environmental exposures for 12 metals increasingly used in metal-mixtures analyses. CONCLUSIONS:As metal epidemiology moves towards embracing a multi-metal approach it is important for researchers to have a strong knowledge base about the metals they are including in their analysis. This review provides researchers with sufficient background knowledge on several metals to appropriately inform their analysis planning, statistical approach, and interpretation of results. KEYWORDS: Heavy metals, Chemical exposures, Biomarkers of exposure, Mixtures, Toxicology

Combined exposure to low level neurotoxic chemicals and child's neuropsychological performance

BACKGROUND AND AIM: Generally, early life exposures to environmental pollutants occur at low levels and their contribution to child’s cognitive abilities, still largely unknown, is a subject of many on-going studies. At low exposures, accounting for multiple neurotoxicants, as well as beneficial elements and genetic variability is important. This study explored prenatal and childhood exposure to trace elements, organophosphate and pyrethroid pesticides and its association with neuropsychological scores. METHODS: Children were recruited in the Ljubljana Maternity Hospital (Slovenia) at birth and were assessed for neuropsychological performance at 7-8 years of age (WISC IV, n=178). Extensive information on life-style was obtained for both periods. Essential and non-essential trace element levels were determined at birth (cord blood), and at follow-up in peripheral whole blood, plasma and urine. Organophosphate and pyrethroid pesticides metabolites were determined in children’s urine at follow-up. RESULTS:Among the potentially neurotoxic substances, 4-nitrophenol, representing parathion exposure, showed negative association with full scale IQ of the children (coeff=-2.09, p=0.022) in a model adjusted for plasma selenium (coeff=16.5, p=0.037) and whole blood copper (coeff=-14.5, p=0.033) (Model R²=0.10, p=0.005). Additional adjustment revealed borderline significant positive effect of breastfeeding in infancy, language classes, and negative effect of watching TV during weekdays, and resulted in a stronger correlation coefficient between 4-nitrophenol and IQ (coeff=-3.03, p=0.004) and stronger overall model (R²=0.27, p0.001). Mercury exposure in prenatal period was positively associated with IQ in the same model (coeff=2.77, p=0.046), most probably indicating beneficial effect of fish consumption during pregnancy. CONCLUSIONS:Although the majority of children had their exposure estimates below the known health-based values, this study demonstrated an importance of evaluating mixed exposures, essential elements as well as child’s cognitive activities along the critical periods of development when estimating their neuropsychological impacts. Continuing this work, paraoxonase genetic polymorphism will be considered and model outcomes will be verified using machine learning approaches. KEYWORDS: trace elements, pesticides, nutrients, neuropsyhological performance

Differential strategies of two species of arbuscular mycorrhizal fungi in the protection of maize plants grown in chromium-contaminated soils.

Chromium (Cr) is a nonessential element for plants that is extremely toxic at high concentrations. Zea mays L. is a species of plant that has developed adaptive mechanisms to increase its tolerance and absorption capacity for this metal. One effective mechanism is to form associations with arbuscular mycorrhizal fungi (AMF), which help the plant cope with stress from heavy metals such as Cr. However, it is still not clear which species of AMF are more efficient as bioremediating agents for plants of agricultural importance. Here, we evaluated the effect of Gigaspora gigantea and Rhizophagus irregularis as protective agents of maize plants in soils contaminated with Cr at concentrations of 0, 48.5, 97 and 194mgkg-1 under greenhouse conditions. Maize tolerance to Cr was corroborated, as well as increased absorption of this element by plants associated with both species of AMF. G. gigantea caused an increase in nitrogen content and greater translocation of Cr to the aerial part of the plant; R. irregularis registered an increase in the formation of arbuscules and vesicles with increasing metal concentration and greater retention of Cr in the roots of the plants. Based on these results, we can conclude that the analyzed species of fungi use different strategies, with similar effectiveness, to enhance the absorption capacity of Cr by the plant and influence the differential deposition of this metal in various parts of the plant.

Effects of cadmium on antioxidant and non-specific immunity of Macrobrachium nipponense

As a non-essential and toxic element, cadmium poses an important threat to aquatic organisms and human food safety. In this study, the effects of cadmium on antioxidant and non-specific immunity of Macrobrachium nipponense were studied from the physiological and biochemical indexes, histology and expression of related genes. These results showed that low concentrations (0.01, 0.02 mg/L) of cadmium have a positive effect on the non-specific immunity of M. nipponense, but high concentration (0.04 mg/L) of cadmium could inhibit or even damage the non-specific immunity of M. nipponense. The cadmium could induce oxidative stress in M. nipponense, and M. nipponense actived the antioxidant defense system to deal with oxidative stress, but high concentration (0.04 mg/L) of cadmium could inhibit the antioxidant defense system of M. nipponense, leading to oxidative damage, and may induce apoptosis in severe case. At the same time, the results of histology showed that cadmium can damage the structure of gill and hepatopancreas tissues of M. nipponense. This study provides theoretical data for evaluating the influences of heavy metal cadmium on M. nipponense and the toxic mechanism of heavy metal cadmium.

Effects of Silicon and Silicon-Based Nanoparticles on Rhizosphere Microbiome, Plant Stress and Growth.

Simple SummaryAbiotic and biotic stresses are a major challenge for agricultural production. To deal with stressed conditions, many techniques, including the use of nanoparticles (NPs), could be considered to mitigate the adversities mediated by these stresses. The application of silicon (Si) and Si-NPs has emerged as a common agronomic technique as it is regarded as a sustainable option. Because of their innumerable benefits, the usage of Si and Si-NPs has attracted a great deal of interest. As a result, their application has been found to minimize the detrimental effects of various stressors by modifying morpho-physiological indices in plants and rhizospheric microbiome characteristics.Silicon (Si) is considered a non-essential element similar to cadmium, arsenic, lead, etc., for plants, yet Si is beneficial to plant growth, so it is also referred to as a quasi-essential element (similar to aluminum, cobalt, sodium and selenium). An element is considered quasi-essential if it is not required by plants but its absence results in significant negative consequences or anomalies in plant growth, reproduction and development. Si is reported to reduce the negative impacts of different stresses in plants. The significant accumulation of Si on the plant tissue surface is primarily responsible for these positive influences in plants, such as increasing antioxidant activity while reducing soil pollutant absorption. Because of these advantageous properties, the application of Si-based nanoparticles (Si-NPs) in agricultural and food production has received a great deal of interest. Furthermore, conventional Si fertilizers are reported to have low bioavailability; therefore, the development and implementation of nano-Si fertilizers with high bioavailability could be crucial for viable agricultural production. Thus, in this context, the objectives of this review are to summarize the effects of both Si and Si-NPs on soil microbes, soil properties, plant growth and various plant pathogens and diseases. Si-NPs and Si are reported to change the microbial colonies and biomass, could influence rhizospheric microbes and biomass content and are able to improve soil fertility.

Health Risk Assessment of Exposure to Trace Elements from Drinking Black and Green Tea Marketed in Three Countries.

Although tea can be beneficial for our health, consuming excess trace elements in tea can be harmful. In this study, the carcinogenic and noncarcinogenic health risk for trace elements in tea influenced by the country of origin, tea type, and infusion process was assessed. Tea (Camellia sinensis) purchased from China, India, and the USA, including black and green tea, were analyzed for essential micronutrients (Cu, Se, and Zn) and nonessential trace elements (Ag, As, Ba, Cd, Cr, and Pb) in leaves and three types of infusions. The results showed that country of origin, tea type, and infusion process had a significant influence on the trace element contents in tea leaves and infusions, also on health risk. Country of origin had a significant influence on Ba, Cr, Pb, and Zn contents in tea leaves and on As, Ba, Cd, Cr, Pb, and Zn contents in tea infusions. Black tea had significantly higher (p < 0.05) Cr and Cu content in tea leaves than green tea, but only Cr content was significantly higher (p < 0.05) than that of green tea in tea infusion. The trace element contents were the highest in the first infusion and decreased as the number of infusion steps increased. The results showed that the consumption of tea infusion was not likely to cause noncarcinogenic risk. However, the carcinogenic risk for As was of concern. Our results indicate that avoiding drinking the first infusion can help to reduce both carcinogenic and noncarcinogenic health risks for trace elements.

Assessment of Essential and Non-essential Elements as Risk Evaluation Indices in Men with Prostate Cancer in Calabar South-South Nigeria

Background: Heavy metal (HM) toxicity has been described as a risk factor for the development of prostate disease in men and its assessment could predict susceptibility to prostate cancer (PCa). The current study aimed to assess the levels of HM (selenium [Se], copper [Cu], chromium [Cr] and lead [Pb], iron [Fe], zinc [Zn], magnesium [Mg], and cobalt [Co]) in men with PCa. Method: 90 men aged 40 to 75 years, including 30 men with PCa, 30 with benign prostatic hyperplasia (BPH), and 30 controls, were recruited in this case-control study. Prostate specific antigen (PSA) was estimated via enzyme linked immunosorbent assay and heavy metals with atomic absorption spectrophotometry. Body mass index (BMI) was also determined. Results: The men with PCa had significantly higher BMI, PSA, Fe, and Pb and lower Mg, Zn, Cu, and Se compared to the controls. They also had higher PSA, Fe, and Co compared to the BPH (P < 0.05). Those with BPH had higher BMI, PSA, and Fe and lower Mg, Zn, Cu, Se, and Co compared to the controls (P < 0.05). Zn was positively correlated with Mg (r = 0.937, P < 0.001, Cu (r = 0.548, P = 0.002), Se (r = 0.731, P < 0.001, and Co (r=0.733, P < 0.001 only in the men with PCa. Levels of Cu, Mg, and Se were associated with the risk of BPH and PCa. Conclusion: The men with prostate disease were found to have higher levels of lead and iron and lower magnesium, copper, selenium, and zinc, which necessitate assessment of these elements for early detection prostate cancer and monitoring the progression of the disease.

How and why plant ionomes vary across North American grasslands and its implications for herbivore abundance.

Plant elemental content can vary up to 1,000-fold across grasslands, with implications for the herbivores the plants feed. We contrast the regulation, in grasses and forbs, of 12 elements essential to plants and animals (henceforth plant-essential), 7 essential to animals but not plants (animal-essential) and 6 with no known metabolic function (nonessential). Four hypotheses accounted for up to two thirds of the variation in grass and forb ionomes across 54 North American grasslands. Consistent with the supply-side hypothesis, the plant-essential ionome of both forbs and grasses tracked soil availability. Grass ionomes were more likely to harvest even nonessential elements like Cd and Sr. Consistent with the grazing hypothesis, cattle-grazed grasslands also accumulated a handful of metals like Cu and Cr. Consistent with the NP-catalysis hypothesis, increases in the macronutrients N and P in grasses were associated with higher densities of cofactors like Zn and Cu. The plant-essential elements of forbs, in contrast, consistently varied as per the nutrient-dilution hypothesis-there was a decrease in elemental parts per million with increasing local carbohydrate production. Combined, these data fit a working hypothesis that grasses maintain lower elemental densities and survive on nutrient-poor patches by opportunistically harvesting soil nutrients. In contrast, nutrient-rich forbs use episodes of high precipitation and temperature to build new carbohydrate biomass, raising leaves higher to compete for light, but diluting the nutrient content in every bite of tissue. Herbivores of forbs may thus be particularly prone to increases in pCO2 via nutrient dilution.