Non-essential Toxic Metal Research Articles

Toxic risk assessment of selected metals in infant formula milk commercially available in Lebanon: A novel approach based on feeding parameters versus toxicity

Infant formula milk (IFM) is increasingly utilized as a substitute for natural breastfeeding despite the fact that breast milk has been always recognized as the optimal nourishment method. While IFMs are fortified with essential nutrients that are crucial for proper growth, they can also harbor non-essential toxic metal contaminants from various sources during the production process. Given the heightened vulnerability of newborns to such contaminants, it is imperative to thoroughly analyze, evaluate, and minimize the toxicity associated with the consumption of such IFMs. However, classical approaches to date, have been always adopted for assessing such risks by finding first the analytical concentration of metals in the IFMs followed by multiplying it by the average daily powder intake (ADI) then dividing by the average infant weight. The outcome is then compared to an established standard such a PTWI to assess the extent of toxicity. The drawback with such studies is the use of a fixed ADI for all samples as if all samples have the same and exact preparation directions while using somewhat different infant masses.Accordingly, this study aims at assessing the toxic risk amongst newborns from IFM consumption through the identification and application of various highly important and toxicity-contributing parameters from each IFM and its directions of preparation label separately which are discussed here for the first time while providing comparisons between the classical approach versus our new approach to highlight its importance.Seventy-three IFMs (0–6 months) were analyzed for lead (Pb), cadmium (Cd), arsenic (As), and aluminum (Al) levels and unlike previous studies, this work incorporated various feeding parameters from each IFM for calculating the intakes thus, revealing potential toxicity risks even in IFMs that are considered safe by the classical approach. Metal contamination was significant, with 97.3 % of samples containing detectable Pb, 41.1 % Cd, 16.4 % As, and 93.2 % Al while highlighting Pb in exceeding its maximum allowable level (MAL). This novel approach, which considers new diverse feeding schedules/parameters that are ironically suggested by manufacturers that have been previously overlooked elsewhere, emphasized IFMs' potential as sources of heightened metal toxicity in comparison to classical approaches. Results highlighted Pb and Al as major concerns, with As and Cd of lesser concern. Findings also emphasized the importance of such new parameters for safeguarding newborn health and should be payed attention to by caregivers. The study strongly and highly recommends adherence to minimum feeding schedules (MFS) and proper scooping techniques to reduce newborn exposure to toxic metals. It also suggests continuous monitoring and stricter regulations by health authorities at the production level of such products so as to provide a safer commodity in the first degree and to also provide better and somewhat uniform and specific feeding labels and precautions on such products.

Interpretation of the adsorption process of toxic Cd2+ removal by modified sweet potato residue.

Cadmium (Cd) is a common and toxic non-essential heavy metal that must be effectively treated to reduce its threat to the environment and public health. Adsorption with an adsorbent, such as agricultural waste, is widely used to remove heavy metals from wastewater. Sweet potato, the sixth most abundant food crop worldwide, produces a large amount of waste during postharvest processing that could be used as an economic adsorbent. In this study, the feasibility of using sweet potato residue (SPR) as an adsorbent for Cd2+ adsorption was assessed. To enhance the removal rate, SPR was modified with NaOH, and the effects of the modification and adsorption conditions on the removal of Cd2+ from wastewater were investigated. The results showed that modified sweet potato residue (MSPR) could be adapted to various pH and temperatures of simulated wastewater, implying its potential for multi-faceted application. Under optimized conditions, the removal of Cd2+ by MSPR was up to 98.94% with a maximum adsorption capacity of 19.81 mg g-1. Further investigation showed that the MSPR exhibited rich functional groups, a loose surface, and a mesoporous structure, resulting in advantageous characteristics for the adsorption of Cd2+. In addition, the MSPR adsorbed Cd2+ by complexation, ion exchange, and precipitation during a monolayer chemisorption adsorption process. This work demonstrates a sustainable and environment friendly strategy for Cd2+ removal from wastewater and a simple approach for the preparation of MSPR and also revealed the adsorption mechanism of Cd2+ by MSPR, thus providing a suitable adsorbent and strategy for the removal of other heavy metals.

Toxic effects of the heavy metal Cd on Apis cerana cerana (Hymenoptera: Apidae): Oxidative stress, immune disorders and disturbance of gut microbiota

Cadmium (Cd) is a toxic non-essential metal element that can enter the honey bee body through air, water and soil. Currently, there is a lack of sufficient research on the effects of Cd on A. cerana cerana, especially the potential risks of long-term exposure to sublethal concentrations. In order to ascertain the toxicological effects of the heavy metal Cd on bees, we performed laboratory-based toxicity experiments on worker bees and conducted analyses from three distinctive facets: antioxidative, immunological, and gut microbiota. The results showed that exposure of bees to high concentrations of Cd resulted in acute mortality, and the increase in mortality was concentration dependent. In long-term exposure to sublethal concentrations, Cd reduced the number of transcripts of antioxidant genes (AccSOD1, AccTPx3 and AccTPx4) and superoxide dismutase activity, causing an increase in malondialdehyde content. Simultaneously, the transcription of immune-related genes (AccAbaecin and AccApidaecin) and acetylcholinesterase activities was inhibited. Furthermore, Cd changes the structural characteristics of bacterial and fungal communities in the gut, disrupting the balance of microbial communities. In conclusion, the health and survival of honey bees are affected by Cd. This study provides a scientific basis for investigating the toxicological mechanisms and control strategies of the heavy metal Cd on honey bees, while facilitating a better understanding and protection of these valuable honey bees.

Mitigation of arsenic accumulation in rice (Oryza sativa L.) seedlings by oxygen nanobubbles in hydroponic cultures

Arsenic (As) is a toxic non-essential metal. Its accumulation in rice has not only seriously affected the growth of rice, but also poses a significant threat to human health. Many reports have been published to decrease the arsenic accumulation in the rice plant by various additives such as chemicals, fertilizers, adsorbents, microorganisms and analyzing the mechanism. Nanobubble is a new technology widely used in agriculture because of its long existence time and high mass transfer efficiency. However, a few studies have investigated the effect of nanobubbles on arsenic uptake in rice. This study investigated the effect of oxygen nanobubbles on the growth and uptake of As in rice. The oxygen nanobubbles could rupture the salinity of nutrients and produce the hydroxyl radical. The hydroxyl radical caused the oxidation of arsenic As(III) to As (V) and the oxidation of ferrous ions. At the same time, the oxidized iron adsorbing As (V) created the iron plaque on the rice roots to stop arsenic introduction into the rice plant. The results indicated that the treatment of oxygen nanobubbles increased rice biomass under As stress, while they increased the chlorophyll content and promoted plant photosynthesis. Oxygen nanobubbles reduced the As content in rice roots to 12.5% and shoots to 46.4%. In other words, it significantly decreased As accumulation in rice. Overall, oxygen nanobubbles mitigated the toxic effects of arsenic on rice and had the potential to reduce the accumulation of arsenic in rice.

The mechanism of cadmium exposure-induced lymph node necroptosis and inflammation in piglets: Activation of CYP450 through VDR / CREB1 pathway

Cadmium (Cd) is toxic non-essential heavy metal that precipitates adverse health effects in humans and animals, but the effect of Cd on lymph node toxicity of piglets is still unclear. In order to explore the possible molecular mechanism of Cd toxicity to lymph nodes of piglets, ten 6-week-old male weaned piglets were randomly divided into two groups, C group and Cd group. Group C was fed with basal diet, while group Cd was fed with basal diet supplemented with CdCl2 (20 mg/kg) for 40 days, the pigs were euthanized and the mesenteric, inguinal and submandibular lymph nodes (MLN, ILN, SLN) were collected. The results indicated that Cd could induce the inflammatory cell infiltration, microvascular hemorrhage, microthrombosis and cell necrosis in MLN, ILN and SLN of piglets, induced Cytochrome P450 proteins (CYP1A1、CYP2E1、CYP2A1 and CYP3A2) mRNA levels and the protein levels of Vitamin D receptor (VDR) and cAMP response element binding protein 1 (CREB1). In addition, Cd exposure upregulated the mRNA and protein levels of dynamin-related protein 1 (DRP1), receptor-interacting protein kinase 3 (RIP3), mixed lineage kinase domain-like protein (MLKL), and increased tumor necrosis factor-α (TNFα), interferon-γ (IFNγ), interleukin-2 (IL-2), interleukin-4 (IL-4), cyclooxygenase 2 (COX-2) protein levels, and the damage degree of three kinds of lymph nodes was similar after Cd exposure. In general, these results manifest that Cd exposure regulates VDR/CREB1 pathway, activates CYP450s, induces necroptosis of lymph nodes, and leads to inflammation.

Exposure to waterborne cadmium induce disorder of lipid metabolism, antioxidant system and autophagy in the muscle of crayfish Procambarus clarkii

Cadmium (Cd) is a non-essential toxic metal in the body, which can cause harmful effects on the aquatic environment and aquatic organisms. In this study, the effects of acute Cd exposure on lipid metabolism disorder, oxidative stress and autophagy in abdominal muscles of Procambarus clarkii were investigated, as well the underlying molecular mechanisms were explored. P. clarkii were exposed to 0 (control), 1 and 5 mg Cd/l, respectively, for 5 days. We found that TG content, fas, hsl, and cpt1 gene expression levels, as well as the Srebp1 protein content in abdominal muscle decreased with the Cd concentrations increased, indicating that acute Cd exposure induced disorder of lipid metabolism in the abdominal muscle of P. clarkii. Further studies showed that acute Cd exposure provoked oxidative stress in the abdominal muscle of P. clarkii by increasing the accumulation of malondialdehyde (MDA) in the abdominal muscle. The oxidative stress of abdominal muscle induced by acute Cd exposure may be due to the reduction of catalases (CAT) and glutathione peroxidase (GPX) enzyme activities and Nrf2 protein content in the nucleus. The expression levels of autophagy-related genes (beclin1, atg101, atg13, atg3, atg4b, atg5, atg7, lc3a, lc3c atg9a) were also affected by acute Cd exposure, suggesting that acute Cd exposure also affected autophagy activity in abdominal muscle of P. clarkii. Our research indicates that waterborne acute Cd exposure can induce lipid metabolism disorder, and oxidative stress, and inhibit the expression of genes that trigger autophagy in the abdominal muscle of P. clarkii. These results may be useful for understanding the mechanism of Cd muscular toxicity in crustaceans.

Metabolic effects of long-term cadmium exposure: an overview.

Cadmium (Cd) is a toxic non-essential heavy metal. Chronic low Cd exposure (CLCE) has been associated with distinct pathologies in many organ systems, including liver and kidney damage, osteoporosis, carcinogenicity, or reproductive toxicity. Currently, about 10% of the global population is at risk of CLCE. It is urgent to find robust and effective biomarkers for early diagnosis of Cd exposure and treatment. Metabolomics is a high-throughput method based on mass spectrometry to study the dynamic changes in a series of endogenous small molecular metabolites (typically < 1000Da) of tissues, cells, or biofluids. It can reflect the rich and complex biochemical changes in the body after exposure to heavy metals, which may be useful in screening biomarkers to monitor exposure to environmental pollutants and/or predict disease risk. Therefore, this review focuses on the changes in metabolic profiles of humans and rodents under long-term Cd exposure from the perspective of metabolomics. Furthermore, the relationship between the disturbance of metabolic pathways and the toxic mechanism of Cd is discussed. All these information will facilitate the development of reliable metabolic biomarkers for early detection and diagnosis of Cd-related diseases.

Chronic Cadmium Exposure Induces Impaired Olfactory Learning and Altered Brain Gene Expression in Honey Bees (Apis mellifera).

The honey bee (Apis mellifera) plays vital ecological roles in the pollination of crops and the maintenance of ecological balance, and adult honey bees may be exposed to exogenous chemicals including heavy metals during their foraging activities. Cadmium (Cd) is regarded as a nonessential toxic metal and is readily accumulated in plants; honey bees can therefore acquire Cd through the collection of contaminated nectar. In the present study, honey bees were chronically exposed to Cd to investigate the effects of sublethal cadmium doses on the olfactory learning and brain gene expression profiles of honey bees. The results showed that Cd-treated bees exhibited significantly impaired olfactory learning performances in comparison with control bees. Moreover, the head weight was significantly lower in Cd-treated bees than in control bees after chronic exposure to Cd. Gene expression profiles between the Cd treatment and the control revealed that 79 genes were significantly differentially expressed. Genes encoding chemoreceptors and olfactory proteins were downregulated, whereas genes involved in response to oxidative stress were upregulated in Cd-treated bees. The results suggest that Cd exposure exerts oxidative stress in the brain of honey bees, and the dysregulated expression of genes encoding chemoreceptors, olfactory proteins, and cytochrome P450 enzymes is probably associated with impaired olfactory learning in honey bees.

The rice heavy-metal transporter OsNRAMP1 regulates disease resistance by modulating ROS homoeostasis.

Crop diseases threaten food security and sustainable agriculture. Consumption of crops containing nonessential toxic metals leads to health risks for humans. Therefore, cultivation of disease-resistant and toxic metal-safe crops is a double-gain strategy that can contribute to food security. Here, we show that rice heavy-metal transporter OsNRAMP1 plays an important role in plant immunity by modulating metal ion and reactive oxygen species (ROS) homoeostasis. OsNRAMP1 expression was induced after pathogenic bacteria and fungi infections. The osnramp1 mutants had an increased content of H2 O2 and activity of superoxide dismutase, but decreased activity of catalase, showing enhanced broad-spectrum resistance against bacterial and fungal pathogens. RNA-seq analysis identified a number of differentially expressed genes that were involved in metal ion and ROS homoeostasis. Altered expression of metal ion-dependent ROS-scavenging enzymes genes and lower accumulation of cations such as Mn together induced compromised metal ion-dependent enzyme-catalysing activity and modulated ROS homoeostasis, which together contributed towards disease resistance in osnramp1 mutants. Furthermore, the osnramp1 mutants contained lower levels of toxic heavy metals Cd and Pb and micronutrients Ni and Mn in leaves and grains. Taken together, a proof of concept was achieved that broad-spectrum disease-resistant and toxic heavy-metal-safe rice was engineered by removal of the OsNRAMP1 gene.

Protective Role of the Essential Trace Elements in the Obviation of Cadmium Toxicity: Glimpses of Mechanisms.

Cadmium (Cd) is toxic non-essential heavy metal that precipitates adverse health effects in humans and animals. Chelation therapy, the typical treatment for cadmium toxicity, has certain safety and efficacy issues to treat long term cadmium toxicity, in particular. Recent studies have shown that essential trace elements can play important roles in obviating experimental Cd toxicity. This study organizes and reviews the prototypical evidences of the protective effects of essential trace elements against Cd toxicity in animals and attempts to point out the underlying mechanisms. Zinc, selenium, iron, and combinations thereof are reported to be active. The major mechanisms elucidated inter alia are-induction of metallothionein (MT) synthesis and Cd-MT binding (for zinc), modulation of oxidative stress and apoptosis, interference in cadmium absorption and accumulation from body-thereby maintenance of essential metal homeostasis and cytoprotection. Based on the findings, essential trace elements can be recommended for the susceptible population. The application of these trace elements appears beneficial for both the prevention and remediation of long-term Cd toxicity operative via multiple mechanisms with no or minimal adverse effects as compared to the conventional chelation therapy.

BcNRAMP1 promotes the absorption of cadmium and manganese in Arabidopsis

Cadmium (Cd) is a toxic nonessential metal that poses a health risk for humans. Cd is easily accumulated in leaf vegetables than in other vegetables. Leafy vegetables are one of the major dietary Cd sources for the human body. In this study, pak choi was used as our experimental material as it is an important leafy vegetable, especially in Asia. A NRAMP transporter – BcNRAMP1 was identified in pak choi, which is involved in manganese (Mn) and Cd uptake in yeast and in planta. BcNRAMP1 is expressed in the whole plant body of pak choi, with a higher abundance in root tissues than in shoots. Mn deficiency and Cd exposure strongly induced BcNRAMP1 transcription levels. Through transient expression of BcNRAMP1-GFP fusion protein in tobacco leaf epidermal cells, BcNRAMP1 was revealed as a plasma membrane protein. Expressing BcNRAMP1 in yeast enhanced yeast cells to absorb Mn, Cd, and iron (Fe). Overexpression of BcNRAMP1 in Arabidopsis wild-type and nramp1 mutant increased and complemented Mn and Cd transportation and accumulation, respectively. Using noninvasive microelectrode ion flux measurements, a direct evidence that BcNRAMP1 acts on Cd influx in Arabidopsis root cells was provided. The results of this study reveal that BcNRAMP1 functions as a NRAMP protein in planta, absorbing nutrient metal Mn and the toxic metal Cd.

Seasonal comparision of levels of cadmium chloride in fresh water fish Catla catla of Bilawali and Sirpur Lake

Fresh water bodies are facing serious type of pollution of heavy metal. Heavy metals are a metal of relatively high density, relative atomic weight or atomic number. Heavy metal are either essential nutrients (like cobalt, zinc) and other may be toxic (like cadmium, mercury, lead). Heavy metals cannot be easily removed by processes like oxidation, precipitation or other processes because they are stable compounds. For aquatic organisms and humans, Cadmium is a toxic non-essential heavy metal that is introduced to environment as a result of the weathering of soil/ rocks, from volcanic eruption /from various human activities involving mining and processing of ore, use of fertilizers and pesticides. Cadmium can affect biological functions in fish and cause severe histopathological, biological and physiological changes in various fish species. The three body parts of fish had been taken gills, muscle and liver because the heavy metal enter in body by three possible ways gills, skin and digestive tract in fish and then transported by blood to either a storage point such as bone, or to liver for transportation. The mean highest values of concentrations of heavy metal in dry tissues of all sampled fish species collected from Sirpur Lake and Bilawali Lake is pointed out in results. These levels might be due to anthropogenic inputs and industrial activity around the lake. The change in season may also contribute to differences in uptake of heavy metal. The purpose of this study is to check the tissue-specific heavy metal accumulation in the fresh water fish (Catla catla) in two different seasons.

Effect of calcium and iron-enriched biochar on arsenic and cadmium accumulation from soil to rice paddy tissues

Arsenic (As) and cadmium (Cd) are nonessential toxic metal(loids) that are carcinogenic to humans. Hence, reducing the bioavailability of these metal(loids) in soils and decreasing their accumulation in rice grains is essential for agroecology, food safety, and human health. Iron (Fe)-enriched corncob biochar (FCB), Fe-enriched charred eggshell (FEB), and Fe-enriched corncob-eggshell biochar (FCEB) were prepared for soil amelioration. The amendment materials were applied at 1% and 2% application rates to observe their alleviation effects on As and Cd loads in rice paddy tissues and yield improvements using pot trials. The FCEB treatment increased paddy yields compared to those of FCB (9–12%) and FEB (3–36%); this could be because it contains more plant essential nutrients than FCB and a lower calcite content than that of FEB. In addition, FCEB significantly reduced brown rice As (AsBR, 29–60%) and Cd (CdBR, 57–81%) contents compared to those of the untreated control (CON). At a 2% application rate, FCEB reduced the average mobility of As (56%) and Cd (62%) in rhizosphere porewater and enhanced root Fe-plaque formation (76%) compared to those of CON. Moreover, the enhanced Fe-plaque sequestered a substantial amount of As (171.4%) and Cd (90.8%) in the 2% FCEB amendment compared to that of CON. Pearson correlation coefficients and regression analysis indicated that two key mechanisms likely control AsBR and CdBR accumulations. First, rhizosphere soil pH and Eh controlled As and Cd availabilities in porewaters and their speciation in the soil. Second, greater Fe-plaque formation in paddy roots grown in the amended soils provided a barrier for plant uptake of the metal(loids). These observations demonstrate that soil amendment with Fe-enriched corncob-eggshell biochar (e.g., 2% FCEB) is a prospective approach for the remediation of metal accumulation from the soil to grain system while simultaneously increasing paddy yield.

Cadmium distribution in soils, soil litter and cacao beans: a case study from Colombia

Cadmium is a toxic non-essential metal for almost all living systems. It is one of the biggest challenges for farmlands and the food chain because of its toxic effect on human health. This research aims to determine the Cd content in soils, litter and cacao beans, following the Cd fluxes within each cacao system using the two-dimensional electrical resistivity tomography technique. The study was carried out in four farms located in the Magdalena basin in Antioquia, Colombia. The farms showed a heterogeneity in relation to cacao cultivars, altitude, topography and geology. The soil cation electrical capacity, pH and soil organic matter levels, as well as the Al, Al3+H+, Ca, K, Mg and P contents were measured at different depths. Moreover, the Cd content was correlated to the resistivity values of samples taken in situ using ERT. Soil Al3+H+ and the altitude of the farms fitted as the best predictors of the beans’ Cd content. Furthermore, the Cd content in soils from the assessed farms ranged between 1.22 and 2.03 mg kg−1. The Cd content in cocoa beans ranged from 0.07 to 1.44 mg kg−1, with a value of 0.40 mg kg−1 on average. The resistivity values obtained in field showed a high correlation with the soil Cd content determined (R2 = 0.82). The predictive tomography plots highlighted topsoil Cd dynamics between litter, amendments and fertilizers. Therefore, these results underlie the utility of the combined geophysical techniques and soil chemical properties including the analysis of fertilizer amendments to improve the understanding of Cd dynamic.

Identification of QTLs for Cadmium Tolerance During Seedling Stage and Validation of qCDSL1 in Rice

Cadmium (Cd) is a non-essential toxic metal that is harmful to plants. To investigate the genetic mechanism of Cd tolerance in rice, quantitative trait loci (QTLs) associated with Cd tolerance at the seedling stage were analyzed using a recombinant inbred line (RIL) population derived from a cross between PA64s and 93-11. A total of 36 QTLs associated with shoot length, root length, shoot dry weight, root dry weight and total dry weight were detected in Hangzhou and Lingshui of China. Among them, 15 QTLs were identified under the control condition and 15 QTLs were identified under the Cd stress condition, and 6 QTLs for Cd tolerant coefficient were detected on chromosomes 1, 3, 7 and 9. The qCDSL1.1 and qCDSL1.2 were identified in Hangzhou and Lingshui, respectively, and had overlapping intervals on chromosome 1. To further confirm the effects of qCDSL1.1 and qCDSL1.2, we developed a chromosome segment substitution line (CSSL), CSSLqCDSL1, in 93-11 background harboring qCDSL1.1/qCDSL1.2 from PA64s. Compared to 93-11, CSSLqCDSL1 had increased shoot length under the Cd stress condition. These results pave the way for further isolation of those genes controlling Cd tolerance in rice and marker-assistant selection of rice elite varieties with Cd tolerance.

Growth and nutritional responses of wild and domesticated cacao genotypes to soil Cd stress

Cadmium (Cd), a toxic non-essential metal, is easily accumulated in cacao tissues. This represents a risk for cacao exportation, and consequently it affects the economic well-being of the resource-poor-small-producers in Latin America. A greenhouse experiment was conducted with 53 wild and domesticated cacao genotypes to determine their response to Cd in terms of growth and Cd and essential nutrients accumulation. Cacao seedlings were grown for 6 months in an acidic soil with or without added Cd. The total concentration of macro (Ca, K, Mg, N and P) and micronutrients (B, Cu, Fe, Mn and Zn) as well as Cd were measured in shoots along with growth (biometric) parameters after harvest. The results revealed that even if there was a wide range of Cd concentrations among genotypes, there was a reduction in the concentration of essential nutrients in genotypes grown in Cd spiked soils, however these concentrations were not significantly different from the control. In the case of growth parameters, the effects of Cd were diverse across all genotypes some of them being more tolerant to Cd stress than others. Thus, different growth responses to Cd stress are related to a genotype effect. Based on their lower Cd concentration, a total of 11 cacao genotypes (AYP-22, PAS-105, UGU-126, ICT-1026, ICT-1087, ICT-1189, ICT-1292, PH-17, CCN-51, ICS-39 and TSH-565) are proposed here as low Cd-accumulating genotypes. Therefore, these genotypes are potentially useful as rootstock to reduce uptake and transport of Cd, especially in economically important cacao cultivars.

Interactive effects of cadmium and Benzo[a]pyrene in adult zebrafish (Danio rerio) during short-term aqueous co-exposure.

Environmental water quality guidelines often work under the assumption that the toxicity of environmental pollutants is identical when present in isolation or in a complex chemical mixture. Thus, there is a crucial gap in our knowledge regarding how these toxicants interact and alter the toxicological effects in aquatic organisms. The present study examined the effects of acute (72-hr) aqueous exposures of Cadmium (Cd), a highly toxic non-essential trace metal, and Benzo[a]Pyrene (B[a]P), a prototypical polycyclic aromatic hydrocarbon (PAH) in adult zebrafish. Following a range-finding series of individual single-toxicant exposures, a second series was carried out using select concentrations in binary mixture exposures (using 5.8 or 22μg/L for Cd; 0.44 or 1.07μg/L for B[a]P). Our results demonstrated that tissue accumulation of both toxicants increased significantly in the presence of the second toxicant relative to single-toxicant exposures. Cd-only and B[a]P-only single toxicant exposures caused a significant downregulation of cytochrome p4501a (CYP1A1) and metallothionein-2 (MT2) mRNA in the gills, respectively, however binary co-exposures using both toxicants resulted in strong up-regulation of CYP1A1 and MT2. Additionally, co-exposures caused a strong induction of SOD1 and CAT mRNA transcript levels in the gill. The observed increase in body burden and transcript modulation did not translate into additive or more-than-additive toxic effects (oxidative stress) in zebrafish.

Foliar application of abscisic acid mitigates cadmium stress and increases food safety of cadmium-sensitive lettuce (Lactuca sativa L.) genotype.

Cadmium (Cd2 +) is among the toxic non-essential heavy metals that adversely affect plants metabolic processes and the safety of produce. However, plant hormones can improve plant’s tolerance to various stresses. This study investigated the effect of exogenous abscisic acid (ABA) on the biochemical and physiological processes and food safety of cadmium (Cd2 +)-sensitive lettuce genotype (Lüsu). Seedlings were subjected to five treatments: [(i) Control (untreated plants), (ii) 100 µM CdCl2, (iii) 100 µM CdCl2+10 µg L−1 ABA (iv) 10 µg L−1 ABA, and (v) 0.01 g L−1 ABA-inhibitor (fluridone)] for fourteen days in hydroponic system. The 100 µM CdCl2 increased the contents of hydrogen peroxide (H2O2) and malondialdehyde (MDA), decreased photosynthesis and plant biomass. Moreover, it decreased the contents of essential nutrients (except copper) in the leaves but increased the contents of toxic Cd2 + in the leaves and roots of the plants. Foliar application of fluridone (0.01 g L−1) also caused oxidative stress by increasing the contents of H2O2 and MDA. It also decreased the contents of nutrient elements in the leaves of the plants. However, exogenous ABA (10 µg L−1) mitigated the Cd2 +-induced stress, increased antioxidant enzymes activities, photosynthesis and plant biomass under CdCl2 treatment. Remarkably, exogenous ABA increased the contents of essential nutrient elements but decreased the Cd2 + content in leaves under the CdCl2 treatment. Our results have demonstrated that foliar application of ABA mitigates Cd2 + stress and increases the nutritional quality and food safety of Cd2 +-sensitive lettuce genotype under CdCl2 treatment.

Seafood consumption is associated with higher follicular fluid arsenic (As) and mercury (Hg) concentrations in women undergoing in vitro fertilization (IVF)

Human exposure to non-essential toxic metals such as cadmium (Cd), mercury (Hg), and lead (Pb), and metalloids such as arsenic (As) commonly occurs through diet. Toxic trace element exposures have been reported in association with fertility and fecundity in epidemiologic studies even at low to moderate levels. While most previous studies employed blood and urine biomarkers of exposure, few have assessed toxic trace elements in ovarian follicular fluid (FF), which surrounds the developing oocyte and hence may better reflect concentrations potentially affecting reproductive outcomes. Our objective was to identify dietary predictors of FF toxic trace elements in n = 56 women (mean age: 38.3 years) undergoing in vitro fertilization (IVF) at the University of California at San Francisco. We determined As, Hg, Cd, and Pb in 197 FF specimens, collected on the day of oocyte retrieval, using inductively coupled plasma tandem mass spectrometry. A comprehensive food frequency questionnaire was used to assess the weekly and annual dietary “patterns” of participants. Consumption of specific seafood items and turkey were correlated with individual FF toxic trace elements. We also found that each unit higher seafood consumption in the past week dominated by mollusks, shrimp, and bass was associated with 60% higher FF As (95% confidence interval (CI): 25%, 105%) and FF Hg (95%CI: 7%, 136%) concentrations. Higher annual seafood consumption dominated by urchin, crab, and trout was associated with 16% higher FF As (95%CI: −2%, 38%) and 31% higher FF Hg (95%CI: 7%, 60%) concentrations per unit intake. No associations were noted between diet and Cd and Pb levels in FF. Overall, our results suggest that higher seafood consumption contributes to elevated levels of As and Hg in FF. These findings are consistent with previous IVF studies that assessed toxic trace element exposures in blood and urine. To our knowledge, this is the first study to report that diet might be a source of As, Hg, Cd, and Pb in FF.

Protective effect of Antigonon leptopus (Hook et. Arn) in cadmium induced hepatotoxicity and nephrotoxicity in rats

BackgroundAntigonon leptopus is a medicinal plant its leaves has not been reported for protective effects against cadmium induced hepatorenal toxicity. Cadmium (Cd) is a non-essential toxic metal used in industrial process, causes severe risk to human health with high levels. It is accumulated primarily in liver and kidney.MethodsMale Wistar albino rats (200-250 g) were divided into 6 groups (n = 6) and had free access to diet and water. Cadmium chloride (5 mg/kg b.w/day) was administered orally for 21 days and methanolic extract of Antigonon leptopus (ALME) was administered to groups of cadmium treated rats at daily doses of 100, 200 and 400 mg/kg b.w;p.o. for 21 days. At the end, liver and kidney markers along with antioxidant parameters are evaluated.ResultsThe results indicated that, administration of cadmium significantly (p < 0.05) increased the levels liver enzymes in serum and bilirubin levels, decreases in total proteins and albumin; in addition to the levels of uric acid, urea and creatinine were increased in the serum. Glutathione (GSH) levels and the enzyme catalase activities were significantly(p < 0.05) decreased while lipid peroxidation was increased in hepatic and renal tissues of cadmium treated rats. The pre-administration of ALME at all the three test doses, alleviated hepatorenal toxicity in cadmium treated rats, used Silymarin (100 mg/kg) as standard. Moreover, ALME treatment was able to reverse the histopathological changes in liver and kidney tissues, and increased the red blood cells, hemoglobin content and decreased prothrombin time and white blood cells.ConclusionAmong all the three test doses, ALME at 200 mg/kg have shown significant antioxidant effect and also exerts beneficial effect against cadmium induced hepatorenal toxicity.