Cd Intake Research Articles

The snake Bothrops jararaca (Squamata: Viperidae) is a suitable bioindicator of environmental exposure to cadmium: An experimental study

• B. jararaca has proven a feasible model for biomonitoring Cd contamination. • The righting response and damage index tests have proven suitable methods for use at experimental level. • Cd in tissues was detected in quantities as follows: liver > kidney > venon gland > fat > gallbladder > tail > blood > heart, demonstrating its bioaccumulation. • Cd content in the feces are an indicator for Cd accumulation in the tissue of the analyzed reptilian specie. Cadmium (Cd) is a highly toxic contaminant causing diverse physiologic damage through the food chain, possibly influencing the demography of wild populations. Thus study aimed to evaluate the feasibility of using Bothrops jararaca as an indicator of Cd contamination. For this purpose, 20 B. jararaca individuals were divided into four groups: a control group and three treatment groups (n = 5 in each group), which received Cd-contaminated food (900 mg kg −1 ) once, twice, or thrice, with a 15-day interval between meals. Animal fitness was evaluated by righting response behavior. In addition, genotoxic effects (comet assay damage index – DI), Cd accumulation in the kidney, liver, heart, gallbladder, fat, venom gland, blood, and tail, and Cd contents in the feces were evaluated. Righting response was negatively related to the number of received meals. Comet assay DI was significantly increased in animals that were fed two or three times. After three contaminated meals, Cd distribution within the body was as follows (µg/g – median): liver (6.24) > kidney (1.88) > venom gland (0.93) > fat (0.85) > gallbladder (0.65) > tail (0.46) > blood (0.45) > heart (0.25). Cd contents in the liver, kidney, and feces were significantly greater in animals that consumed Cd-contaminated food for two or three times. However, Cd accumulation in the liver started to appear after the first meal comprising the highest Cd concentration, while accumulation in the kidney appeared after the third feeding. It can be concluded that B. jararaca is a feasible model for biomonitoring Cd using the liver as a prognostic organ for the bioaccumulation as well as righting response and the damage index as indicators of Cd effects at an experimental level. Field monitoring feces stood out as the most suitable indicator for Cd ingestion by B. jararaca .

Influence of biochar amendment and foliar application of iron oxide nanoparticles on growth, photosynthesis, and cadmium accumulation in rice biomass

The majority studies used the biochar or nanoparticles alone in metal-contaminated soils while less is known about the combined use of these amendments in metal-contaminated soils. We aimed to explore the efficiency of iron oxide nanoparticles (Fe NPs) and biochar on cadmium (Cd) uptake in rice in pot trial. An experiment was performed under ambient environmental conditions in a Cd-contaminated soil with and without biochar addition (1.0% w/w), and different Fe NP concentrations (0, 10, 20, 30 mg/L) were foliar sprayed at different time intervals (at 3rd, 4th, and 5th weeks of nursery transplantation in the pots) during the plant growth. After harvesting, rice growth, photosynthesis, Cd and Fe contents in rice tissues, and soil bioavailable Cd and soil pH were measured. Iron NPs enhanced the dry weights of rice tissues, chlorophyll concentrations, and gas exchange characteristics and the impact of NPs was further increased when the biochar was applied along with NPs. Iron NPs significantly decreased the intake of Cd in rice shoots by 31 and 42% and in rice roots by 26 and 39% with the foliar spray of Fe NPs (30 mg/L) without and with biochar, respectively. Foliar spray of Fe NPs reduced the total Cd accumulation by shoots, whereas the total Cd accumulation in the roots increased. The co-presence of Fe NPs and Cd enhanced the Fe concentrations in shoots of rice by 52 and 33% and in roots of rice by 32 and 21% when 30 mg/L Fe NPs were supplied with and without biochar, respectively. The effects of Fe NPs were higher with biochar application than without biochar except Fe concentrations in rice seedlings where the opposite trend was observed. The increase in biomass, Fe concentrations in tissues, and decrease in Cd levels in plants clearly demonstrate that Fe NPs + biochar could be a promising technique for the utilization of Cd-contaminated soils in the future.

Association between Cadmium Air Exposure and Prostate Cancer Stage at Diagnosis

IntroductionThere is clear evidence that high levels of occupational exposure to cadmium (Cd) lead to a more aggressive prostate cancer (PC) tumor. At levels of exposure which are more relevant to the general population, there is disputing evidence as to whether Cd causes a PC tumor to become more aggressive. In this study, we assess the relationship between ambient exposure to air Cd and PC stage at diagnosis.MethodsWe collected outcome data from the Surveillance, Epidemiology, and End Results (SEER) for reported PC cases diagnosed from 2010 to 2014. PC stage at diagnosis was categorized as metastatic or localized. Exposure data was collected from the 2011 National Air Toxics Assessment (NATA) which was developed by the EPA to review air toxics in the United States. The total exposure concentration of Cd compounds in the air was a county‐level metric calculated by the EPA using weighted averages of air Cd concentration levels measured at various point emission sources. We calculated quintiles of Cd exposure concentration for ease of interpretation. Odds Ratios (OR) and 95% confidence intervals (CI) assessing the relationship between county‐level air Cd exposure and PC stage at diagnosis were calculated using multivariable logistic regression models. Analyses were adjusted for age at diagnosis, sociodemographic status, and overall air quality and were stratified by race.ResultsThe study cohort consisted of 234,991 PC cases from 594 counties reported by SEER. Of these cases, 92.5% were localized and 7.5% metastatic at diagnosis. Higher levels of air Cd exposure were associated with an increased likelihood of a PC case being metastatic at diagnosis. The adjusted odds ratios for the 80th percentile vs 20th percentile of Cd exposure were: all races (OR 1.030, CI 1.019 – 1.040), White (1.049, CI 1.037 – 1.062), Black (1.032, CI 1.0072 – 1.057), and other races (0.965, CI 0.925 – 1.0062).ConclusionHigher Cd air exposure concentration was associated with advanced PC stage at diagnosis with effects that vary somewhat by race. Since inhalation of Cd in the air only contributes to a small percentage of total Cd intake, further studies should be conducted to investigate the effects of other forms of Cd intake such as dietary and water exposures on PC aggressiveness.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Molecular dissection of cadmium-responsive transcriptome profile in a low-cadmium-accumulating cultivar of Brassica parachinensis

Brassica parachinensis L., a daily consumed leaf vegetable, is a high-Cd accumulator that substantially threatens human health. Screening and breeding Cd pollution-safe cultivars (Cd-PSCs) of crops is a low-cost strategy to restrict human Cd intake from contaminated soils via the food chain. However, little is known about the molecular mechanisms underlying the low-Cd-accumulating traits of B. parachinensis Cd-PSCs. In the current study, we analyzed the transcriptomes of the Cd-treated (5 μM) roots and shoots of a low-Cd-accumulating cultivar (SJ19) and a high-Cd-accumulating cultivar (CX4) of B. parachinensis to reveal the molecular mechanisms in response to Cd stress. Compared to CX4, many pathways involved in carbohydrate and amino acid metabolisms were exclusively up-regulated in SJ19 roots upon exposure to low Cd concentrations, which may produce more energy and metabolites for Cd detoxification. Antioxidant enzymes in the peroxisome were up-regulated in both SJ19 and CX4 roots in response to Cd, while glutathione biosynthesis was only activated in SJ19 roots. In SJ19 shoots, pathways of photosynthesis and cell growth were activated to mitigate Cd-induced damages. Furthermore, Cd transport genes, such as MTP1, HMA3 and CAX family genes, were highly induced by Cd stress in SJ19 roots in accordance with the high Cd concentration in roots, while genes involved in root-to-shoot Cd translocation such as FRD3 and CESA3 were suppressed, which may contribute to the low Cd concertation in edible part of SJ19. Our study provides a genetic basis for further Cd-PSCs screening and breeding.

Heavy Metals Contamination and Potential Human Health Risk via Consumption of Vegetables from Selected Communities in ONELGA, Rivers State, Nigeria

Background: Anthropogenic activities such as excessive oil exploration, automobile emissions with agricultural activities, etc tend to elevate the concentrations of heavy metals in the soil. These metals are accumulated by plant roots, thereby resulting to heavy metal contamination of such plants.
 Objectives: This study evaluated the concentration of heavy metals namely: Lead (Pb), Cadmium (Cd), Nickel (Ni), Arsenic (As), Iron (Fe), and Copper (Cu) in edible vegetables from selected communities in Ogba/Egbema/Ndoni Local Government Area (ONELGA), Rivers State, Nigeria, and the concentrations of these metals were used to assess the human health risk posed to the consumers of the edible vegetables.
 Materials and Methods: Sixteen different vegetable samples comprising Vernonia amygdalina, Talinum triangulare, Abelmoschus esculentus and Telfairia occidentalis were digested and analyzed for heavy metals using Flame Atomic Absorption Spectrophotometer (F-AAS). Results obtained from this study were used to estimate the human health risk of these heavy metals.
 Results: The results showed that the concentrations of Pb, Cd, Ni, As, Fe, and Cu ranged from 0.168-4.908; 0.364-2.977; 2.780-10.241; 0.157-2.633; 61.589-101.520 and 12.029-46.540 mg/kg, respectively. The concentrations of Pb, Cd, Ni and As in some of the analyzed vegetable samples exceeded the permissible limit as recommended by WHO/FAO, EC/CODEX and NAFDAC respectively. The concentration of Fe and Cu were below the permissible limit as recommended by WHO/FAO. The Estimated Daily Intake (EDI) of Pb and Cd exceeded the permissible tolerable daily intake of metals (TDI) but fall within the upper tolerable daily intake (UTDI) recommended by Institute of medicine, FDA, also Ni, Fe, and Cu fall within the recommended TDI and the UTDI. The EDI values of As exceeded the recommended TDI and the UTDI. The Target Hazard Quotient (THQ) and Hazard Index (HI) values of Pb, Cd, Cu and Ni were greater than 1. The Life Cancer Risk (LCR) of Pb were within the range of permissible predicted lifetime risks for carcinogens as recommended by US EPA.
 Conclusion: The result from the present study indicate that the exposed population may be at risk of Pb, Cd, Ni and Cu toxicity.

Producing cadmium-free Indica rice by overexpressing OsHMA3

BackgroundConsiderable proportions of rice grains produced in some areas in southern China contain high concentrations of cadmium (Cd), leading to unsafe levels of dietary Cd intake. Cultivars of Indica rice, widely grown in southern China, are particularly prone to high Cd accumulation in the grain. Effective methods are needed to decrease Cd accumulation in Indica rice. MethodsOsHMA3, encoding a tonoplast Cd transporter, was overexpressed in an elite Indica rice cultivar (Zhongjiazao 17) driven by CaMV 35S promoter. The effects on Cd translocation, accumulation and tolerance, as well as on the agronomic traits and micronutrient concentrations were evaluated. ResultsOsHMA3 overexpression markedly decreased Cd translocation from roots to shoots and increased Cd tolerance. OsHMA3 overexpression decreased Cd concentrations in brown rice by 94–98%, to levels just above the detection limit, when rice plants were grown in two Cd-contaminated paddy soils. OsHMA3 overexpression generally had no significant effect on grain yield and the concentrations of the essential micronutrients including zinc, iron, copper and manganese in field trials. ConclusionOverexpression of OsHMA3 is a highly effective method to reduce Cd accumulation in Indica rice, producing rice grains that were almost Cd free with little effect on grain yield or essential micronutrient concentrations.

Cadmium Accumulation in Peruvian Cacao (Theobroma cacao L.) and Opportunities for Mitigation

Crops are the main source of toxic cadmium for humans due to uptake from naturally or anthropogenically polluted soils. Chronic Cd ingestion causes kidney, liver, and skeletal damage along with an increased risk of cancer. Cacao is known to accumulate Cd and may therefore be potentially harmful to human health. Consequently, cocoa production on intensely polluted soils should be avoided. Cocoa products from South America in particular often exceed the limits for Cd, but the factors that drive Cd uptake are as yet poorly studied. In this study, we measured Cd concentrations in defatted cocoa powder from unfermented seeds of 40 different trees on 20 farms in the Huanuco Region, Peru, and associated the Cd levels with the farms’ soil, field management, and nearby vegetation diversity. The mean Cd concentration found in cocoa of the study region was 2.46 mg kg−1 with a range of 0.2–12.56 mg kg−1. The maximum content measured was an order of magnitude higher than the allowed limit of 1.5 mg kg−1 and was the highest reported so far in the literature. Soil Cd content was the most relevant driver of Cd concentration in cacao. In addition, fertilizer use caused significantly higher Cd concentration in cocoa. Higher biodiversity of herbs was positively correlated with Cd contents in cocoa. The study shows that, apart from the known correlation of soil conditions with Cd accumulation in cacao seeds, changes in fertilization and plant composition may be promising measures to counteract Cd contamination in regions with high soil Cd content.

Accumulation, ecological-health risks assessment, and source apportionment of heavy metals in paddy soils: A case study in Hanzhong, Shaanxi, China

Contamination of agricultural soil by heavy metals has become a global issue concerning food security and human health risk. In this study, a soil investigation was conducted to evaluate metals accumulation, potential ecological and health risks as well as to identify sources of metals in paddy soils in Hanzhong City, which is located in a sedimentary basin. Ninety-two (92) surface soil samples (bulk soil) and their corresponding rice samples, 21 irrigation water samples, and 18 fertilizer samples were collected from two typical counties and quantified for the heavy metals (i.e., As, Cd, Cu, Hg, Pb, and Zn) concentrations. The results showed that As, Cd, and Zn were the main contaminants in soils in the studied area. Additionally, elevated Hg content in soils might also pose risks to the local ecosystem. Cadmium and As demonstrated high mobility, and their average contents in rice grains were slightly higher than the permissible threshold (0.20 mg kg−1). Moreover, Pb, As, and Cd intake via rice consumption might result in potential risks to local residents. Metal distribution revealed that pollution in the studied area is non-homogeneous, and agricultural activities (As, Cu, and Cd), transportation emission (Cu and Pb), coal combustion (Hg and As), and smelting activities (Zn, Pb, and Cu) were ascertained as the potential sources based on the Positive matrix factorization (PMF) analysis results.

The potential risk of heavy metals on human health due to the daily consumption of vegetables

Background: Vegetables are one of the most important components of daily food. Thus, this research was done to evaluate the potential risk of heavy metals on human health due to the consumption of vegetables distributed in the fruits and vegetables central market of Arak, Iran. Methods: In this study, a total 45 samples from edible parts of parsley, mint, chard, fenugreek, cress, basil, coriander, lettuce, and cabbage distributed in the fruits and vegetables central market of Arak were randomly collected and the concentration of heavy metals including lead (Pb), cadmium (Cd), and arsenic (As) in these crop plants was measured using atomic absorption spectrophotometer (AAS). The non-carcinogenic risk of heavy metals intake through the consumption of the studied vegetables was evaluated for male and female using the Environmental Protection Agency (EPA) method. Results: The highest and lowest Pb daily intake and Pb risk index was related to the consumption of cabbage and basil, respectively. And the highest daily intake of Cd and As was related to lettuce consumption, while the lowest daily intake of these metals was related to the consumption of coriander. Among the studied heavy metals, As had the highest hazard quotient (HQ) for non-carcinogenic diseases. The highest HQ belonged to As through lettuce consumption and the lowest one belonged to As through coriander consumption (58 g/day). The HQ for female was higher than that for male. Conclusion: According to the results, the total hazard quotient (THQ) of non-carcinogenic diseases from the total studied vegetables was above the standard level. On the other hand, the HQ for female was higher than that for male.

Accumulation of Cd in Ophiopogon Japonicus, Houttuynia Cordata and Duchesnea Indica, and Its Human Health Risk Assessment

In this paper, Chinese herbal medicines of Ophiopogon japonicus, Houttuynia cordata and Duchesnea indica were planted in the soil containg 0.847 mg/kg Cd, which is close to the grade III of Environmental Quality Standard for Soil in China (GB15618-1995). After growth a certain time, the Cd in the three plants were determined respectively. Then the human health risk of Cd intake via taking the herbal medicines was assessed using the internationally recommended method of health risk assessment, as well as accordance to the Standards of Import and Export of Green Medicinal Plants and Their Preparations (WM2-2001), and the Acceptable Daily Intake (ADI) of World Health Organization (WHO). The results showed that, after growth 90d, the Cd contents in the leaves and roots of O. japonicus and H. cordata, and all parts of D. indica were lower than the safe value of Green Trade Standards of Importing & Exporting Medicinal Plants & Preparations (WM2-2001), while that in stems of H. cordata was higher than the safe value. The human health risk of Cd in the three herbal medicines was in the order of H. cordata＞O. japonicu＞D. indica. Under the asumption of 30g as the average daily intake of the three herbal medicines for an adult, the maximum amount of Cd intake per person via O. japonica, H. cordata, and D. indica were 8.7μg, 10.5μg and 6.2μg respectively, which were lower than the allowable daily Cd intake value of WHO and the limit value recommended by the International Committee for Radiological Protection (ICRP). However, as the stem of H. cordata was slightly polluted after growth 90d in grade III soil, it was not recommended to use it as an edible Chinese herbal medicine.

Nutritional status and risks of potentially toxic elements in some paddy soils and rice tissues

This experiment was conducted to investigate the potential risk of toxic elements in paddy soils and rice straws, bran, and husked grains in Kuchesfahan, Gilan, Iran. The average content of total and DTPA-extractable of Cd, Cu, Fe, Mn, Ni, Pb, and Zn were 7.0, 26.3, 20728.8, 1516.7, 43.8, 16.6, and 211.8 mg kg−1, and 0.32, 14.1, 97.3, 63.4, 1.7, 4.8, and 56.2 mg kg−1, respectively. In addition, the average content of Cd, Cu, Fe, Mn, Ni, Pb, and Zn in rice grain was 0.16, 2.4, 135.5, 34.1, 2.0, 0.6, and 15.0 mg kg−1, respectively. The average transfer factor for Cd, Cu, Fe, Mn, Ni, Pb, and Zn from soil to straw was 0.38, 0.16, 0.004, 0.13, 0.3, 0.04, and 0.09, respectively. The average values of estimated daily intake for Cd, Cu, Fe, Mn, Ni, Pb, and Zn through rice consumption for adult are respectively, estimated to be 0.0004, 0.005, 0.32, 0.08, 0.005, 0.0015, and 0.035 mg kg−1 body weight per day. There was no health risk index (HRI) values for adult greater than 1 (except three samples for Fe, and one sample for Mn and Cd); indicated that intake of single metal through the consumption of rice was safe. The average of heath index (HI) value for rice consumption was 0.33 and 0.35 for adult and children, respectively. Therefore, combination of several potentially toxic elements may not cause risk to local residents. Spatial distributions of HRI were obtained for potentially toxic metals in husked grains.

Cadmium and Lead Hazardous Impact Assessment of Pond Fish Species.

The current study aims to assess the concentration of cadmium (Cd) and lead (Pb) in five tissues of Cirrhinus mrigala, Labeo rohita, and Catla catla collected from fishponds of Jamshoro and Larkana, Sindh, Pakistan. Meanwhile, the levels of Cd and Pb in feeding materials, water, and sediments of fishponds of both areas were also studied. The daily intake and hazardous impact assessment of Cd and Pb by muscles of three fish species of fishponds of both areas were estimated. The concentration of Cd in tissues of C. mrigala and C. catla of Larkana were higher than that in tissues of same fish species of Jamshoro whilst Pb contents in tissues of fishes of Jamshoro were high (p > 0.05). The feeding materials of fishponds of Larkana were enriched with Cd whilst Pb was high in feeding material of fishponds of Jamshoro. The estimated bioaccumulation factor, average daily intake, and hazardous quotient of Pb were high as compared to Cd in all studied fish species of fishponds of Larkana and Jamshoro. The hazardous quotient of Pb indicated that the local population of both areas might have a potential toxic risk. Graphical abstract ᅟ.

Impact of the coal mining-contaminated soil on the food safety in Shaanxi, China.

The study aimed to investigate the impacts of coal mining-contaminated soil on the locally grown food crops and humans health. For the active investigation and assessment, the study collected 175 samples including contaminated and control soil and various types of food crops (corn, wheat, mixed food (egg, pork meat, potato, pepper)) from Shaanxi Province. All these samples were analyzed through ICP-MS and ICP-OES. Results show that in Weibei soil, the average concentration (mgkg-1) of Cr (194 ± 94), Cu (27 ± 13), Cd (0.6 ± 0.3), Ni (83 ± 35), Be (1.98 ± 0.8), Rb (115 ± 68), Li (74 ± 78), Sr (148.5 ± 67), and Zn (3056 ± 2380) was higher than that of the Chinese soil standard (CSS) and upper continental crust (UCC) (P < 0.01-0.05). In Langao soil, the averageconcentration (mgkg-1) of Cr (99.5 ± 48), Cu (77 ± 32), Ni (113 ± 37), Pb (45 ± 19.8), Cd (2.9 ± 1.7), Co (13.9 ± 2.4), Mo (28.7 ± 16), Be (2.98±0.5), Li (81.8 ± 9.7), V (430 ± 166), Zn (255 ± 105), and Ba (1347 ± 445) was higher than that of the CSS and UCC. However, in Binxian Jurassic all the toxic trace elements (TTE) were higher than the CSS and UCC. In Langao contaminated vegetable, Na, Cd, Tl, In, Mo, Li, U, Bi, and Th may cause very high risk, whereas Al, Mn, P, Fe, Ca, Cr, Ni, Pb, Co, Cs, Rb, and Ba may cause considerable risk. However, the average daily intake (ADI) of Al, Mn, P, Fe, Cd, Mo, and Ba was higher than the No Observable Adverse Effect Level (NOAEL). However, the non-carcinogenic risk of Al, Mn, P, Fe, Cr, Cu, Ni, Pb, Cd, Co, Tl, Mo, Li, V, Ba, and Th was higher than acceptable level (HQ = 1). In Binxian wheat, Al, Tl, Cs, Bi, and Th may cause very high risk, and Ti, Na, K, Fe, Ca, Cr, Ni, Cd, Pb, Sr, Bi, and U may cause considerable risk. However, ADI of Al, Mn, P, Ti, Fe, Cu, Ni, Pb, Mo, Ba, and U for both adults and children was higher than the NOAEL. In Weibei, the wheat crops are prone to considerable-to-moderate elemental risk. The non-carcinogenic risk of Al, Mn, P, Fe, Cr, Cu, Pb, Co, Tl, Mo, Li, Zn, and Th was higher than the acceptable level. In countryside adults and children, ADI was lower than the NOAEL except Al, P, and Zn. The study concluded that human activities of coal mining release a high amount of TTE to the soil. Majority of arable land, grain food and vegetable were contaminated through TTE, which may cause high risks to human's health and the environment.

Disulfiram partially improves oxidative but not androgen status in rats exposed to cadmium

We investigated the effect of disulfiram (DSF) on reproductive toxicity induced by subchronic exposure to cadmium (Cd). We examined the redox status and systemic testosterone changes in the testes and plasma of Cd-treated male Wistar rats. Rats were treated with 1 mg CdCl2/kg body weight (bw)/day (intraperitoneal administration) for 42 days; in the second experimental group, rats were given 178.5 mg DSF/kg bw/day by oral gavage for 21 days; in the third group, after administration of Cd for 21 days, DSF treatment was introduced on day 22 and lasted until day 42, with continuous Cd intake. Each experimental group had a matching control: untreated rats, rats that received for 21 days olive oil, the solvent for DSF; rats that started with olive oil intake from days 22-42. Exposure of rats to DSF modulated the oxidative status in the testes; thus, coexposure increased the Cd-induced reduction in total superoxide dismutase (tSOD), catalase (CAT), glutathione reductase (GR) and total glutathione-S-transferase (tGST) activities, and lowered the Cd-increased superoxide anion radical (O2 ??) and malondialdehyde (MDA) concentrations. DSF did not affect testosterone production diminished by Cd, as Leydig cells, once impaired by Cd, could not be reactivated by DSF. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III41018] &lt;br&gt;&lt;br&gt;&lt;font color="red"&gt;&lt;b&gt; This article has been corrected. Link to the correction &lt;u&gt;&lt;a href="http://dx.doi.org/10.2298/ABS200226010E"&gt;10.2298/ABS200226010E&lt;/a&gt;&lt;u&gt;&lt;/b&gt;&lt;/font&gt;

Effects of boron, silicon and their interactions on cadmium accumulation and toxicity in rice plants.

Cadmium (Cd) is a highly toxic heavy metal for both animals and plants. Rice consumption is a major source of Cd intake for human. Minimization of Cd accumulation in rice is key to reduce Cd hazard to human. Here we showed alleviating effects of boron (B), silicon (Si) and their mixture on Cd accumulation and toxicity in hydroponically-cultured rice plants. Cd treatment (100 μM) led to Cd accumulation in roots and shoots, as well as significant reduction in plant growth. However, amendment of either B or Si significantly alleviated Cd accumulation and toxicity. Moreover, simultaneous supply of B and Si showed better alleviating effect. However, addition of B and Si alleviated Cd-induced oxidative stress in Cd-treated plants as reflected by reduced MDA, H2O2 and O2-, as well as increased activities of major antioxidant enzymes. Cd exposure induced the expression of Cd transporter genes of OsHMA2, OsHMA3, OsNramp1 and OsNramp5. In contrast, simultaneous supplement of B and Si in Cd-treated plants compromised the gene expression. Our results show that both B and Si alleviate Cd accumulation and toxicity by improving oxidative stress and suppressing Cd uptake and transport, and the two elements display joint effect.

Dietary Cadmium Intake and Sources in the US.

Cadmium (Cd) is a toxic heavy metal that can contribute to numerous diseases as well as increased mortality. Diet is the primary source of Cd exposure for most individuals, yet little is known about the foods and food groups that contribute most substantially to dietary Cd intake in the US. Therefore, the objective of this study was to estimate dietary Cd intake and identify major food sources of Cd in the US population and among subgroups of the population. Individuals aged 2 years and older from the National Health and Nutrition Examination Survey (NHANES) 2007–2012 were included in this study (n = 12,523). Cd intakes were estimated from two days of 24-h dietary recalls by matching intake data with the Cd database of the Food and Drug Administration (FDA)’s Total Diet Study 2006 through 2013. The average dietary Cd consumption in the population was 4.63 μg/day, or 0.54 μg/kg body weight/week, which is 22% of the tolerable weekly intake (TWI) of 2.5 μg/kg body weight/week. Greater daily Cd intakes were observed in older adults, males, those with higher income, higher education, or higher body mass index. The highest Cd intakes on a body weight basis were observed in children 10 years and younger (38% of TWI), underweight individuals (38% of TWI), and alcohol non-consumers (24% of TWI). The food groups that contributed most to Cd intake were cereals and bread (34%), leafy vegetables (20%), potatoes (11%), legumes and nuts (7%), and stem/root vegetables (6%). The foods that contributed most to total Cd intake were lettuce (14%), spaghetti (8%), bread (7%), and potatoes (6%). Lettuce was the major Cd source for Caucasians and Blacks, whereas tortillas were the top source for Hispanics, and rice was the top contributor among other ethnic subgroups including Asians. This study provides important information on the dietary Cd exposure of Americans, and identifies the groups with the greatest dietary Cd exposure as well as the major sources of dietary Cd among sociodemographic subgroups.

Evaluation of Possible Human Health Risk of Heavy Metals from the Consumption of Two Marine Fish Species Tenualosa ilisha and Dorosoma cepedianum.

In order to study the effects of contaminants on human health, fish is considered as a powerful model among all available species for risk-benefit assessments. Tenualosa ilisha and Dorosoma cepedianum are two fish species of great economic importance as they are found in undeveloped, developing and developed countries. Concentrations of heavy metals lead (Pb), cadmium (Cd), chromium (Cr), arsenic (As) and mercury (Hg) were determined using validated and accredited test methods in order to assess the potential human health risk from the dietary intake of these two selected fish species. The estimated daily intake (EDI) of all the five heavy metals was measured from the consumption of the two species considering the mean fish consumption of 61gperson-1day-1 defined for European population. The EDI indicates that no risk to people's health with respect to the EDI of Pb, Cd, Cr, As and Hg through the consumption of the two fish species. The estimation of target hazard quotient (THQ) demonstrating the non-carcinogenic risk indicates that intake of Pb, Cd, Cr and Hg through the consumption of two fish species is safe for human health, whereas, consumption of As suggests potential risk to consumers. The estimation of carcinogenic risk of Cd, Cr and As due to the consumption of two selected fish species indicates that consumers remain at risk of cancer. Thus, these fish species should not be considered safe for human consumption.

Low-dose cadmium disrupts mitochondrial citric acid cycle and lipid metabolism in mouse lung

Cadmium (Cd) causes acute and chronic lung toxicities at occupational exposure levels, yet the impacts of Cd exposure at low levels through dietary intake remain largely uncharacterized. Health concerns arise because humans do not have an effective Cd elimination mechanism, resulting in a long (10- to 35-y) biological half-life. Previous studies showed increased mitochondrial oxidative stress and cell death by Cd yet the details of mitochondrial alterations by low levels of Cd remain unexplored. In the current study, we examined the impacts of Cd burden at a low environmental level on lung metabolome, redox proteome, and inflammation in mice given Cd at low levels by drinking water (0, 0.2, 0.6 and 2.0 mg Cd/L) for 16 weeks. The results showed that mice accumulated lung Cd comparable to non-smoking humans and showed inflammation in lung by histopathology at 2 mg Cd/L. The results of high resolution metabolomics combined with bioinformatics showed that mice treated with 2 mg Cd/L increased levels of lipids in the lung, accompanied by disruption in mitochondrial energy metabolism. In addition, targeted metabolomic analysis showed that these mice had increased accumulation of mitochondrial carnitine and citric acid cycle intermediates. The results of redox proteomics showed that Cd at 2 mg/L stimulated oxidation of isocitrate dehydrogenase, malate dehydrogenase and ATP synthase. Taken together, the results showed impaired mitochondrial function and accumulation of lipids in the lung with a Cd dose response relevant to non-smokers without occupational exposures. These findings suggest that dietary Cd intake could be an important variable contributing to human pulmonary disorders.

Soil contamination near the Kabwe Pb-Zn smelter in Zambia: Environmental impacts and remediation measures proposal

Kabwe Town and its surroundings (central Zambia) belong to the most contaminated districts in Africa due to mining and smelting of local Pb-Zn ores. To assess the extent and intensity of this anthropogenic contamination, samples of topsoil (from a depth of 0 to 3 cm), together with reference subsurface soil from a depth of 70–90 cm, were collected in the area. In the Kitwe Town and downwind, the Pb and Zn contents in topsoils were found to be significantly higher compared to the permissible ecological limits used in Canada with regard to various land uses. Other elements (Cu, Fe, Mn, Cr, Ni and Ba) in topsoil demarcate only a small area of the former ore processing and smelter grounds.The gastric bioaccessibility of metals in topsoils was tested by a US EPA-adopted in vitro method using a simulated gastric fluid. The results revealed that the intake of Cd, Cu, Zn, Co, and As does not exceed the tolerable daily intake (TDI) values for children but, for Pb, almost 50% of the samples exceeded TDI. Therefore, the concentrations of gastric bioaccessible Pb in highly contaminated topsoils or in resuspended soil-derived dust particles may be considered to be an important health risk in the Kabwe area.The amounts of plant-available metals in topsoils were established by extraction with a diethylentriaminopentanacetic acid (DTPA) and triethanolamine (TEA) solution. These tests showed that the amounts of plant-available metals increase (median values, in mg kg−1) in the sequence: Cd (0.7) → Cu (3.9) → Mn (76) → Fe (79) → Zn (110) → Pb (126). Chemical stabilization of the pollutants in soils using a phosphate amendment caused a significant reduction of the plant-available fraction of Pb and Cd, but did not suppress their gastric bioaccessibility. Based on our results, various measures were suggested to reduce the impact of the pollution on the Kabwe Town population.

Heavy metals in human urine, foods and drinking water from an e-waste dismantling area: Identification of exposure sources and metal-induced health risk

Electronic waste or e-waste dismantling activities are known to release metals. However, the human exposure pathways of metals, and their association with oxidative stress in e-waste dismantling areas (EDAs) remain unclear. In this study, our results revealed elevated geometric mean concentrations in vegetables (Cd 0.096 and Pb 0.35 µg/g fw), rice (Cd 0.15, Pb 0.20, and 12.3 µg/g fw), hen eggs (Cd 0.006 and Pb 0.071 µg/g fw), and human urine (Cd 2.12, Pb 4.98, Cu 22.2, and Sb 0.20 ng/mL). Our calculations indicate that rice consumption source accounted for the overwhelming proportion of daily intakes (DIs) of Cd (61–64%), Cu (85–89%), and Zn (75–80%) in children and adults living in EDA; vegetables were the primary contributors to the DIs of Cd (30–32%); and rice (20–29%), vegetables (28–38%), and dust ingestion (26–45%) were all important exposure sources of Pb. Risk assessment predicted that DIs of Cd, Pb, Cu, and Zn via food consumption poses health risks to local residents of EDAs, and the urinary concentrations of analyzed metals were significantly (Pearson correlation coefficient: r = 0.324–0.710; p < 0.01) associated with elevated 8-OHdG, a biomarker of oxidative stress in humans.