Cadmium Consumption Research Articles

Cadmium: A Focus on the Brown Crab (Cancer pagurus) Industry and Potential Human Health Risks.

Cadmium is a major health risk globally and is usually associated with pollution and anthropogenic activity. The presence of cadmium in food is monitored to ensure that the health and safety of consumers are maintained. Cadmium is ubiquitous in the Asian and Western diets, with the highest levels present in grains, leafy greens, and shellfish. As part of their natural lifecycle of moulting and shell renewal, all crustaceans—including the brown crab (Cancer pagurus)—bioaccumulate cadmium from their environment in their hepatopancreas. The brown crab is an important species to the crab-fishing industries of many European countries, including Ireland. However, the industry has come under scrutiny in Europe due to the presence of cadmium in the brown crab meat intended for live export to Asia. This review explores evidence regarding the effects of cadmium consumption on human health, with a focus on the brown crab. Differences in cadmium surveillance have given rise to issues in the crab industry, with economic consequences for multiple countries. Currently, evidence suggests that brown crab consumption is safe for humans in moderation, but individuals who consume diets characterised by high levels of cadmium from multiple food groups should be mindful of their dietary choices.

Association of gut microbiota characteristics and metabolites reveals the regulation mechanisms under cadmium consumption circumstance.

Cadmium is a non-biodegradable heavy metal with a long biological half-life. Although its negative impact on human health has been previously reported, the association of cadmium consumption overdose with changes in the gut microbiota and its corresponding metabolites has not been fully elucidated so far. Cadmium consumption overdose led to a reduced body weight gain accompanied by an enhanced level of the proinflammatory cytokine tumor necrosis factor-α, interleukin-6, and histamine in the serum of the rats in comparison with normal rats. Furthermore, hepatotoxicity was also observed to be induced by cadmium, which was consistent with abnormal hepatic activities of alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferase and oxidative stress. In contrast, Lactobacillus rhamnosus-fermented Ganoderma lucidum (FGL) slice supplementation improved the aforementioned physiological properties. More importantly, microbiome and metabolites analysis indicated cadmium exposure significantly reduced the generation of short-chain fatty acids in the gut, particularly butyrate. However, rats in the FGL group had the highest level of butyrate in the feces, characterized with significantly enriched probiotics (Lactobacillus, Bifidobacterium) and butyrate-producing bacteria (Roseburia). The targeted regulation of the gut microbial community and its metabolites might be the essential association for attenuating body dysfunction induced by cadmium. The supplementation of FGL, as evidenced in this study, might highlight a novel approach to this field. © 2022 Society of Chemical Industry.

Dietary Trace Element Intake and Risk of Breast Cancer: A Mini Review.

Trace elements are essentially required for various physiological and metabolic functions, and any disturbance in the trace elements homeostasis may result in the development of chronic diseases including breast cancer. Breast cancer is the most prevalent cancer type reported in women equally affecting both the high-income and low-income countries. This review therefore aimed to evaluate the impact of dietary trace element intake in relation to the incidence of breast cancer. We focused on five trace elements, thus emphasizing dietary selenium, zinc, iron, copper, and cadmium intake and risk of breast cancer. A systematic approach was applied to perform this review through entering a search term in PubMed and Scopus databases. A total of 24 articles were included after meeting the inclusion and exclusion criteria. Most of the studies regarding dietary iron intake showed a detrimental effect of increased dietary heme iron on breast cancer incidence risk. In addition, there is a limited evidence of high dietary intake of selenium and zinc to reduce the risk of breast cancer. Also, a few studies showed a relationship between high cadmium consumption and risk of breast cancer. More studies related to cadmium and copper exposure are needed to confirm this relationship. As a result, the findings of this review suggested that high dietary heme iron is a potential risk factor for breast cancer.

Accumulation of cadmium in organs of experimental animals and its effect on the content of essential elements in the chronic intoxication

Introduction. This article presents the results of studying the effects of cadmium chloride and its accumulation in experimental animals’ liver, kidneys, and blood. The impact of cadmium consumption on basic bioelements (zinc, copper, calcium) in organs was assessed. Materials and methods. Experimental groups of white outbred rats were exposed daily for three months to a cadmium chloride solution containing 1, 10 and 100 μg of cadmium. Cadmium exposure was assessed at 1, 4, 12, 30, 60 and 90 days. The concentrations of cadmium, calcium, copper and zinc were measured by atomic absorption spectrometry. Results. Whole blood cadmium concentration was not statistically different from the control group. The accumulation of cadmium in the blood was observed only after three months of exposure to a dose of 100 μg. The accumulation of cadmium in the liver occurred after one and two months of intoxication, depending on the dose. In the kidneys, an increase in cadmium occurred in all experimental groups after one month of injection. The metal content depended on the level of exposure, but no difference was observed between the liver and kidney. The concentration of zinc and calcium decreased in the kidneys and liver. Conclusion. Changes in calcium and zinc, accompanied by elevated levels of cadmium in the liver and kidneys, suggest that cadmium may interfere with the biological processes in which these elements are involved.

Identification and immunologic property of macrophage migration inhibitory factor (MIF) in grass carp (Ctenopharynogodon idella)

Macrophage migration inhibitory factor (MIF), a pro-inflammatory cytokine, plays an important regulatory role in the activation of T cells induced by mitogenic or antigenic stimuli. However, the immunologic property of MIF in freshwater fish is limitedly known by now. In the present study, MIF gene was identified in grass carp. Bioinformatics analysis revealed that the molecular weight of grass carp MIF protein was 12.377 kDa and it could also bind to CD74. MIF gene was predominantly expressed in immune tissues including spleen and head kidney, then liver, skin, gill, intestine and blood, while a relative low level expression in heart, brain, fat and red muscle. The predicted receptor and tissues distribution of MIF implied the immunologic activity of grass carp MIF. Then grass carp MIF antigen and the polyclonal antibodies against it were prepared. Using cadmium as an immunosuppressive agent, MIF expression in spleen and head kidney was depressed in a dose-dependent manner with cadmium consumption. On the same time, white blood cell count decrease displayed a similar pattern with MIF expression, which suggested a possible positive correlation between MIF and white blood cell count. Thereafter, MIF enhanced the viability of grass carp peripheral blood leukocytes and inhibited cell apoptosis with depressed reactive oxygen species production in vitro. In addition, recombinant grass carp MIF promoted tumor necrosis factor-alpha (TNF-α), interleukin 1β (IL1β) and interleukin 6 (IL6) secretion from peripheral blood leukocytes. These results indicated the immunologic property of grass carp MIF.

The effects of zinc and magnesium ingestion on essential trace-element accumulation in the organs of white rats upon cadmium exposure

Due to high athropogenic loads on the environment, issues surrounding public health and safety in consumable products are being raised with ever-increasing frequency. One toxic metal, whose consumption results in irreparable harm to the health of animals and human is cadmium. To antagonize such toxic effects to human health, magnesium and zinc are considered being essential elements and their combination effects warrant further studies. To this end, we developed a Wistar rat model to look at the combinatorial effects of cadmium with magnesium and zinc consumption on the accumulation of iron and zinc ions in kidney and liver tissues. Our findings suggested that exposure to cadmium ions reduced zinc ion levels in the liver and kidneys, reduced iron ions in the liver (but were increased in the kidneys), decreased magnesium ions in the kidneys but increased their levels within the liver. Moreover, while the consumption of magnesium and zinc ions individually, partially reduced the effects caused by cadmium consumption alone, the simultaneous consumption of zinc and magnesium ions proved to be significantly more effective.

Antioxidant Effect of High Intensity Interval Training on Cadmium-Induced Cardiotoxicity in Rats

Background: Cadmium is a heavy metal toxicant that effectively disturbs the body's oxidant-antioxidant status; however, high intensity interval training (HIIT) has been reported to improve antioxidant indices such as catalase (CAT) and glutathione peroxidase (GPX), which neutralize free radicals. Objectives: The present study aimed to review the effect of HIIT on CAT and GPX gene expression in the heart tissue of rats with cadmium toxicity. Methods: Twenty-five male Sprague Dawley rats were selected and were divided into five groups, of five rats (1) control, (2) sham, (3) cadmium, (4) HIIT, and (5) HIIT and cadmium. During eight weeks, rats in groups 4 and 5 performed three sessions per week of HIIT and groups 3 and 5 received 2 mg/kg of cadmium daily in peritoneum. To analyze the findings of the research One-way ANOVA with Tukey’s post hoc tests were used (P ≤ 0.05). Results: Cadmium consumption had a significant effect on reduced CAT (P = 0.03) and GPX (P = 0.004). However, HIIT had a significant effect on increased CAT (P = 0.001) and GPX (P = 0.001). Conclusions: It appears that HIIT can improve the CAT and GPX gene expression in the heart tissue of cadmium-infected rats.

Antiapoptotic Effects of Continuous Training and Selenium Consumption on the Liver Tissue of Cadmium-Exposed Rats

Background: Cadmium has negative effects on various tissues of the body while selenium has antioxidant activities. Moreover, the benefits of exercise training for apoptotic factors including caspase-3 and cytochrome c, as well as cyclin D, have been regarded. Objectives: Therefore, the present study aimed to evaluate the anti-apoptotic effects of continuous training and selenium consumption on the liver tissue of cadmium-exposed rats. Methods: In this study, 25 rats were selected and randomly divided into five groups of five rats including: (1) control, (2) selenium consumption, (3) continuous training, (4) continuous training with selenium consumption, and (5) sham. For eight weeks, groups 1 to 4 received peritoneal cadmium (2 mg/kg) daily; groups 2 and 4 received peritoneal selenium (0.23 mg/kg) daily; and groups 3 and 4 performed continuous training three sessions per week. Caspase-3, cytochrome c, and cyclin D were measured at the protein level. Results: Cadmium consumption significantly increased the protein levels of caspase-3 and cytochrome c and decreased cyclin D in rats (P = 0.001). Selenium consumption and continuous training significantly decreased the protein levels of caspase-3 and cytochrome c and increased cyclin D in rats exposed to cadmium (P = 0.001). Continuous training along with selenium consumption had interactive effects on increasing the protein levels of cyclin D in rats exposed to cadmium (P = 0.02). Conclusions: It appears that continuous training and selenium consumption have interactive anti-apoptotic effects in the liver tissue of cadmium-exposed rats.

The Effect of Interval Training with Selenium Consumption on Gene Expression of Caspase- 3 and Cyclin-D in Liver Tissue of Cadmium-Exposed Rats

Background: Cadmium is one of the heaviest metals in the natural environment that can increase DNA damage in liver cells, nevertheless, it has been reported that physical activity and nutrition can improve the damage of DNA in liver cells. Objectives: The aim of the present research was to review the effect of interval training and selenium on cyclin-D and caspase-3 gene expression in liver tissue of cadmium-exposed rats. Methods: In the present experimental research, 30 rats were divided to six groups of (1) control, (2) sham, (3) cadmium, (4) selenium consumption with cadmium, (5) interval training with cadmium consumption, and (6) interval training with selenium and cadmium consumption. For eight weeks, groups three to six received 2 mg/kg of cadmium per day; groups four and six consumed 0.23 mg/kg of selenium per day and groups five and six performed three sessions of selected interval training per week. Results: Cadmium consumption significantly increased cyclin-D and caspase-3 (P = 0.001); selenium consumption and interval training had a significant effect on decreasing caspase-3 and cyclin-D levels (P = 0.001); concurrent interval training with selenium consumption had interactive effects on the increase of cyclin-D (P = 0.001). However, there was no interactive effect on the reduction of caspase-3 (P = 0.75). Conclusions: It seems that interval training with selenium consumption has interactive effects on hepatocyte apoptotic factors in rats exposed to cadmium.

Effects of Resistance and Endurance Training on HIF-1α and VEGF in Heart Tissues of Pregnant Rats with Cadmium Toxicity

Background: Exposure to cadmium can cause cardiovascular disorders, including possible risks of angiogenesis abnormalities associated with Hypoxia Inducible Factor (HIF), in pregnancy period. Objectives: This study aimed to investigate the effects of resistance and endurance training on HIF-1α and vascular endothelial growth factor (VEGF) levels in heart tissue of pregnant rats with cadmium toxicity. Methods: In this study, 48 female rats were selected and divided into 6 groups of 8 rats, including (1) cadmium, (2) resistance training, (3) resistance training with cadmium consumption, (4) endurance training, (5) endurance training with cadmium consumption, and (6) control. Groups 2, 3, 4, and 5 performed three weeks of resistance and endurance training, five sessions per week. Also, groups 1, 3, and 5 received cadmium as cadmium chloride dissolved in water as 400 mg per liter through drinking water. To analyze the data, Kolmogorov-Smirnov, One-way ANOVA, and Tukey’s post hoc tests were used and P ≤ 0.05 was considered statistically significant. Results: Cadmium had a significant effect on the increase of HIF1-α and VEGF (P = 0.001); resistance training had a significant effect on the increase of HIF1-α (P = 0.03), resistance training (P = 0.02) and endurance training (P = 0.001) had a significant effect on the increase of VEGF. Also, resistance training with cadmium consumption as well as endurance training with cadmium consumption significantly decreased HIF1-α (P = 0.001) and VEGF (P = 0.001), compared with cadmium consumption. Conclusions: Cadmium appears to lead to an abnormal increase in HIF-1α and VEGF in the heart tissues of pregnant rats, which can stimulate abnormal angiogenesis of tumors; however, resistance and endurance training can reduce the severity of cadmium effects on abnormal angiogenesis of the heart tissue of pregnant rats.

The Effect of Endurance Training Along with Cadmium Consumption on Bcl-2 and Bax Gene Expressions in Heart Tissue of Rats

Background: Exposure to environmental pollution is a very important factor that disrupts human metabolism. Cadmium is one of the toxic elements of the environment that has deleterious effects on various organs of the body, induces oxidative stress in the cell, and ultimately causes apoptosis. Objectives: The aim of this research was to investigate the effect of endurance exercise along with cadmium consumption on the expression of Bcl-2 and Bax genes in the heart tissue of rats. Methods: In the present experimental research, 25 rats were randomly selected and divided into five groups of five rats (1) control, (2) sham, (3) cadmium consumption, (4) endurance training along with cadmium consumption, and (5) endurance training alone. Groups 3 and 4 received 2 mg/kg of cadmium per day peritoneally and groups 4 and 5 ran on the treadmill for three sessions of 60 minutes per week for eight weeks. For statistical analysis, Kolmogorov-Smirnov, One-way ANOVA, and Tukey's post hoc tests were used (P ≤ 0.05). Results: Cadmium significantly reduced the Bcl-2 gene expression (P = 0.003) and increased the Bax gene expression (P = 0.001) in the heart tissue of rats. On the other hand, endurance training significantly increased the Bcl-2 gene expression (P = 0.002) and reduced the Bax gene expression (P = 0.002) in the heart tissue of the rats. Conclusions: Eight weeks of endurance training can improve the Bcl-2 and Bax gene expressions in the heart tissue of rats exposed to cadmium.

Drastic difference in cadmium concentration in mussels (Mytilus chilensis) observed between seasons in natural bed and aquaculture systems in Chile.

Globally, Chile is the second largest producer of mussels, with 99% of production concentrated in the inland sea of the Los Lagos Region, Southern Chile. This study reveals that seasons produce a drastic difference in the cadmium concentration (Cd) in marine mussels in bay, channel, and fjord ecosystems in this area. As the global mussel industry continues its rapid expansion, a complete understanding of cadmium pathways is critical in order to minimize the cadmium content in harvests. In this study, biweekly sampling was conducted in Chiloé (Southern Chile), during five consecutive seasons from June 2014 to November 2015. Cadmium in the soft tissues (ST) and in the content of the digestive gland (CDG) of Mytilus chilensis were investigated, in addition to resuspensions and seston to determine the effect of the seasons on metal bioassimilation capacity. In spring, the (Cd) between CDG and ST varied by approximately 2mg Cd kg-1 dry mass (DM). In summer and autumn, the (Cd) in CDG increased from 3 to 6mg Cd kg-1 while the (Cd) in ST decreased from 2.5 to 1.5mg Cd kg-1 DM. The three ecosystems showed the same cadmium bioconcentration trends in all seasons, revealing coherent global trends. These findings should caution the industry and coastal populations about the seasonal variability and intensity of cadmium metal transfer to biofilters, especially because of the adverse effects of cadmium consumption on human health. Additionally, this study found that mussels in natural beds concentrate more Cd (> 1mg Cd kg-1 DM) than in industrial facilities. Multiregression analysis showed and explained the cadmium in CDG for three ecosystems: channel (R2 0.9537), bay (R2 0.5962), and fjord (R2 0.4009). The independent variable nocturnal seston was able to explain the increase in cadmium.

Lead and cadmium contamination in a large sample of United States infant formulas and baby foods

Data is limited on lead and cadmium contamination in baby food, a population uniquely susceptible to the toxic effects of heavy metals. The goal of this study was to examine lead and cadmium concentrations in a large convenience sample of US baby foods. We identified the number of baby food product samples that exceeded US FDA and California Proposition 65 limits for daily lead consumption across a range of servings/calories, and the number of samples that exceeded World Health Organization and California Proposition 65 limits for daily cadmium consumption across a range of servings/calories. In total, 564 baby foods were tested across infant and toddler formula, cereals, meals, juices/drinks, jars, pouches, snacks, and electrolyte water. ICP-MS analysis of lead and cadmium was completed using a modified version of EPA method 6020A. Samples were analyzed using kinetic energy distribution mode. Lead was detected in 37% of samples (median = non-detect, 75% = 5.6, maximum = 183.6 μg/kg), and cadmium in 57% (25% = non-detect, median = 2.8, 75% = 9.5, maximum = 103.90 μg/kg). Of 91 infant formula samples, none exceeded FDA lead consumption guidelines in 31 oz, but 22% exceeded the Proposition 65 lead guidelines, 23% exceeded the Proposition 65 cadmium guidelines, and 14% exceeded the WHO tolerable cadmium intake levels for a four-month-old baby. In the solid baby food samples, 1% exceeded FDA lead guidelines in two servings (26% exceeded CA Proposition 65 limits), 3% in 300 cal (34% exceeded CA Proposition 65 limits). For cadmium, 6% exceeded Proposition 65 guidelines in two servings, 8% in 300 cal. There was no association between whether the product was certified organic and its heavy metal concentration. Products containing rice were higher in both lead and cadmium concentrations. Further research is needed to understand the long-term health effects of this chronic daily low level heavy metal exposure in babies.

Effect of Calcium Silicate-biological Humus Fertilizer Composite on Uptake of Cd by Shallots from Contaminated Agricultural Soil

The safety of vegetable production is a key link in reducing cadmium consumption through the food chains. Field experiments were conducted to investigate the effects of composite materials (calcium silicate-biological humus fertilizer) on the growth of shallots and the uptake of Cd by shallots from contaminated agricultural soil. Four treatments (T1: 0.5% calcium silicate+0.5% biological humus fertilizer; T2: 0.5% calcium silicate+1.0% biological humus fertilizer; T3: 1.0% calcium silicate+0.5% biological humus fertilizer; and T4: 1.0% calcium silicate+1.0% biological humus fertilizer) and a control group (CK) were adopted. The changes in soil pH, DTPA-extractable Cd, biomass of shallots, and cadmium concentrations in shallots over time under different treatments were analyzed. The results show that the application of composite amendments decreased the concentrations of DTPA-extractable Cd in the soil. In particular, after T3 treatment, the concentrations of soil DTPA-extractable Cd decreased by 60.71%, 49.54%, 44.63%, and 58.94% after 14, 28, 42, and 56 d, respectively. The biomass of the shallots aboveground increased significantly by 107.99% and 107.19% after T3 and T4 treatment, respectively. The composite amendments exhibited different effects on the uptake of Cd by the shallots from the soil, and the T4 treatment was the most effective in immobilizing Cd and inhibiting translocation of Cd into the shallots. The cadmium concentration in the shallots decreased by 43.80% after 56 d with the T4 treatment. In conclusion, T4 is the optimum treatment for soil cadmium immobilization.

Analyzing the Influence of Diatomite and Mineral Fertilizers on the Features of Cadmium-Contaminated Urban Lawns

Contamination with heavy metals is among key anthropogenic pressures, experienced by urban lawns. It results in depletion of their environmental quality and functions. Implementation of fertilizers, containing silicon, is a promising approach to increase urban lawns’ sustainability to heavy metals’ pollution. Based on the field experiment, an influence of cadmium contamination on the chemical features and biomass quality of modeled urban green lawn ecosystems was studied. We demonstrated an increase of cadmium consumption by biomass on the second year of observations as the result of diatomite implementation together with mineral fertilizers. Both total sugar and disaccharides’ content in biomass was 15-20% higher for the contaminated plots where diatomite was implemented together with mineral fertilizers, compared to the uncontaminated control. This evidences a positive effect of the implemented reclaiming on stress tolerance of the green lawns.

Toxicity of oral cadmium intake: Impact on gut immunity

Gastrointestinal tract is one of the main targets of cadmium (Cd), an important food and drinking water contaminant. In the present study, the effect of subchronic (30 days) oral (in water) intake of 5ppm and 50ppm of cadmium on immune responses in the gut was examined in rats. Cadmium consumption resulted in reduction of bacteria corresponding to Lactobacillus strain, tissue damage and intestinal inflammation [increases in high mobility group box 1 (HMGB1 molecules), superoxide dismutase (SOD) and catalase (CAT) activity and proinflammatory cytokine (TNF, IL-1β, IFN-γ, IL-17) content]. Draining (mesenteric) lymph node (MLN) stress response was observed [elevation of MLN glutathione (GSH) and metallothionein (MT) mRNA levels] and stimulation of both adaptive [cellularity, proliferation, proinflammatory (IFN-γ and IL-17) MLN cell cytokine responses] as well as innate immune activity (increases in numbers of NK and CD68+ cells, oxidative activities, IL-1β). In contrast to proinflammatory milieu in MLN, decreased or unchanged antiinflammatory IL-10 response was observed. Stimulation of immune activities of MLN cells have, most probably, resulted from sensing of cadmium-induced tissue injury, but also from bacterial antigens that breached compromised intestinal barrier. These effects of cadmium should be taken into account when assessing dietary cadmium as health risk factor.

Dietary Cadmium Exposure and Risk of Breast, Endometrial, and Ovarian Cancer in the Women’s Health Initiative

Background: In vitro and animal data suggest that cadmium, a heavy metal that contaminates some foods and tobacco plants, is an estrogenic endocrine disruptor. Elevated estrogen exposure is associated with breast, endometrial, and ovarian cancer risk.Objectives: We examined the association between dietary cadmium intake and risk of these cancers in the large, well-characterized Women’s Health Initiative (WHI).Methods: A total of 155,069 postmenopausal women, 50–79 years of age, who were enrolled in the WHI clinical trials or observational study, participated in this study. We estimated dietary cadmium consumption by combining baseline food frequency questionnaire responses with U.S. Food and Drug Administration data on food cadmium content. Participants reported incident invasive breast, endometrial, or ovarian cancer, and WHI centrally adjudicated all cases through August 2009. We applied Cox regression to estimate adjusted hazard ratios (HRs) and 95% CIs for each cancer, comparing quintiles of energy-adjusted dietary cadmium intake.Results: Over an average of 10.5 years, 6,658 invasive breast cancers, 1,198 endometrial cancers, and 735 ovarian cancers were reported. We observed no statistically significant associations between dietary cadmium and risk of any of these cancers after adjustment for potential confounders including total dietary energy intake. Results did not differ in any subgroup of women examined.Conclusions: We found little evidence that dietary cadmium is a risk factor for breast, endometrial, or ovarian cancers in postmenopausal women. Misclassification in dietary cadmium assessment may have attenuated observed associations.Citation: Adams SV, Quraishi SM, Shafer MM, Passarelli MN, Freney EP, Chlebowski RT, Luo J, Meliker JR, Mu L, Neuhouser ML, Newcomb PA. 2014. Dietary cadmium exposure and risk of breast, endometrial, and ovarian cancer in the Women’s Health Initiative. Environ Health Perspect 122:594–600; http://dx.doi.org/10.1289/ehp.1307054

Bioaccumulation characterization of cadmium by growing Bacillus cereus RC-1 and its mechanism

In an effort to explore the protective mechanism of growing Bacillus cereus RC-1 against the toxicity of different Cd(II) concentrations, bacterial growth, cadmium consumption, surface interactions and intra- and extra-cellular Cd(II) contents were examined. Cellular morphology and growth were evidently affected by the initial metal concentrations above 20mgL−1, according to the analysis of SEM, AFM, TEM and UV spectrophotometer. Surface complexation and electrostatic attraction played an important role in the different Cd(II) concentrations, as determined by the FTIR and Zeta potential analysis. Intracellular accumulation was the predominant mechanism in culture with lower metal concentrations (below 20mgL−1), but was overshadowed by extracellular adsorption at higher concentrations. This suggested that the growing cells might employ one dominant mechanism at lower concentrations and then shift to another at higher concentrations. These results suggest options could be exploited for bioremediation of aqueous solution in which the Cd(II) concentration is less than 20mgL−1.

Long-term Dietary Cadmium Intake and Cancer Incidence

Cadmium, a ubiquitous environmental pollutant, is classified as a carcinogenic substance. Several laboratory and epidemiologic studies of workers and subjects in polluted areas have suggested a positive association between cadmium exposure and risk of several cancers. However, data from general populations are sparse. We prospectively examined the association between cadmium exposure and incidence of cancer in a Japanese population with a relatively high dietary intake of cadmium. We conducted a population-based prospective study in 90,383 Japanese men and women 45-74 years of age. Participants responded to a validated questionnaire that included 138 food items. We estimated dietary cadmium intake from 6 food groups, based on the questionnaire data. During 9 years of follow-up, 5849 cancer cases were identified. Hazard ratios (HRs) and 95% confidence intervals (CIs) for cancer were calculated by Cox proportional hazards modeling. There was no evidence of an association of cadmium consumption and total cancer, with HRs in the highest versus lowest cadmium intake group of 0.94 (95% CI = 0.82 to 1.08; test for trend, P = 0.46) for men and 0.96 (0.81 to 1.15; 0.60) for women. No site-specific cancers were associated with cadmium intake in men or women. We found no associations of cancer with cadmium, at least at the exposure levels observed in a general population in Japan.

Dietary cadmium and risk of invasive postmenopausal breast cancer in the VITAL cohort.

The aim of the study was to estimate the association between dietary intake of cadmium, a carcinogenic heavy metal, and risk of invasive postmenopausal breast cancer. Study subjects were 30,543 postmenopausal women in the VITamins And Lifestyle (VITAL) cohort who completed a food frequency questionnaire (FFQ) at baseline (2000-2002). Dietary cadmium consumption was estimated by combining FFQ responses with US Food and Drug Administration data on food cadmium content. Incidence of invasive breast cancer was ascertained through linkage of the cohort to the western Washington Surveillance, Epidemiology, and End Results cancer registry through 31 December 2009. Cox regression was applied to estimate adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) for breast cancer with increasing dietary cadmium intake, adjusted for total energy intake, smoking history, consumption of vegetables, potatoes, and whole grains, multivitamin use, education, race, body mass index, physical activity, age at first birth, postmenopausal hormone use, and mammography. Vegetables and grains together contributed an average of 66% of estimated dietary cadmium. During a mean of 7.5years of follow-up, 1,026 invasive postmenopausal breast cancers were identified. Among 899 cases with complete covariate information, no evidence of an association between dietary cadmium intake and breast cancer risk was observed (aHR (95% CI), highest to lowest quartile cadmium: 1.00 (0.72-1.41), p (trend)=0.95). No evidence was found for interactions between dietary cadmium and breast cancer risk factors, smoking habits, or total intake of calcium, iron, or zinc from diet, supplements, and multivitamins. This study does not support the hypothesis that dietary cadmium intake is a risk factor for breast cancer. However, non-differential measurement error in the estimate of cadmium intake is likely the most important factor that could have obscured an association.