Total Cadmium Intake Research Articles

Exogenous Caffeine (1,3,7-Trimethylxanthine) Application Diminishes Cadmium Toxicity by Modulating Physio-Biochemical Attributes and Improving the Growth of Spinach (Spinacia oleracea L.)

Leafy vegetables usually absorb and retain heavy metals more readily than most of the other crop plants, and thus contribute ≥70% of the total cadmium (Cd) intake of humans. Caffeine mediates plant growth and has proved to be beneficial against pathogens and insects. Therefore, it was hypothesized that foliar applications of caffeine could alter metabolism and reduce Cd toxicity in spinach (Spinacia oleracea L.). Seven-day old spinach seedlings were provided with Cd (0, 50, and 100 µM) stress. Caffeine (0, 5, or 10 mM) foliar spray was given twice at after 20 days of seeds germination with an interval of one week. In results, Cd stress reduced photosynthetic pigments biosynthesis, increased oxidative stress, imbalanced nutrient retention, and inhibited plant growth. On the other hand, the caffeine-treated spinach plants showed better growth owing to the enhanced biosynthesis of chlorophylls, better oxidative defense systems, and lower accumulation and transport of Cd within the plant tissues. Furthermore, caffeine application enhanced the accumulation of the proline and ascorbic acid, but reduced MDA and H2O2 contents and Cd in plant leaves, and ultimately improved mineral nutrition of spinach plants exposed to different Cd regimes. In conclusion, exogenous application of caffeine significantly diminishes Cd stress by modulating physiological, biochemical, and growth attributes of spinach (Spinacia oleracea L.)

The association between life-time dietary cadmium intake from rice and chronic kidney disease

The association between internal cadmium exposure and chronic kidney disease (CKD) has been investigated before. However, few studies have shown the association between dietary cadmium intake and CKD. In this study, we show the association between life-time dietary cadmium intake and CKD based on a follow-up study. At baseline, we collected blood and urine samples for assays of cadmium and renal effect biomarkers. A questionnaire and food survey was given to each subject to collect diet and lifestyle information for the estimation of cadmium intake. Dietary cadmium, cadmium in blood and urine were regarded as exposure markers. Life-time dietary cadmium intake was estimated based on an individual’s daily cadmium intake and exposure time. At follow-up, 467 persons (163 men and 304 women) were finally included. CKD at follow-up was considered if the estimated glomerular filtration rate (eGFR) was less than 60 mL/min/1.73 m2. The eGFR level in subjects in the highest quartile of total dietary cadmium intake (>9.34 g) was significantly lower than in those with a moderate or low intake (p < 0.01). eGFR was negatively associated with total dietary cadmium intake (β = -0.42, 95% confidence interval (CI): -0.77 to -0.07) after adjustment with confounders. Logistic regression further showed that the risk of CKD in subjects with a high total dietary cadmium intake (>2.2 g) was higher than in those with a low intake (odds ratio (OR) = 18.16, 95%CI: 1.75–188.85). A similar association was found between the baseline urinary albumin (UALB) level and CKD incidence. A predictive model based on UALB and life-time dietary cadmium intake showed an acceptable performance (the area under the curve was 0.77 (95%CI: 0.65–0.88)). Our data show that high dietary cadmium exposure was associated with CKD after controlling for renal tubular dysfunction and internal cadmium exposure.

Exposure Assessment of Cadmium in Female Farmers in Cadmium-Polluted Areas in Northern Japan.

Akita prefecture is located in the northern part of Japan and has many cadmium-polluted areas. We herein performed an exposure assessment of cadmium in 712 and 432 female farmers in two adjacent cadmium-polluted areas (A and B, respectively), who underwent local health examinations from 2001–2004. We measured cadmium concentrations in 100 food items collected from local markets in 2003. We then multiplied the intake of each food item by its cadmium concentration in each subject to assess cadmium intake from food and summed cadmium intake from all food items to obtain the total cadmium intake. Median cadmium intake levels in areas A and B were 55.7 and 47.8 µg/day, respectively, which were both higher than that of the general population and were attributed to local agricultural products, particularly rice. We also calculated weekly cadmium intake per body weight and compared it to the previous provisional tolerable weekly intake reported by the Joint FAO (Food and Agriculture Organization)/WHO (World Health Organization) expert committee on food additives or current tolerable weekly intake in Japan of 7 µg/kg BW/week. Medians in areas A and B were 7.2 and 6.0 µg/kg BW/week, respectively. Similar estimated values were also obtained by the Monte Carlo simulation. These results demonstrated that the cadmium exposure levels among the farmers were high enough to be approximately the tolerable weekly intake.

The references level of cadmium intake for renal dysfunction in a Chinese population

Recent several studies indicated that a more restrictive dietary intake guideline for cadmium should be made for sufficient health protection. In the present study, we showed the references level of food cadmium intake (FCd) and total cadmium intake (TCd) for renal dysfunction by using benchmark dose (BMD) approach. 342 subjects living in a control and a cadmium polluted area were included in this study. The FCd, TCd and cadmium in urine (UCd) and blood (BCd) were calculated or determined. Urinary β2Microglobulin (UBMG) was determined as indicator of renal function. The median FCd, TCd, UCd and BCd were 1.4 g, 1.4 g, 3.1 μg/g creatinine(cr) and 1.3 μg/L in control and 3.3 g, 3.6 g, 13.5 μg/g cr and 12.1 μg/L in polluted area. The 95% lower confidence bounds of BMD (BMDLs) of FCd for renal dysfunction were 1.36–1.55 g (BMR = 10%) and 0.88–1.11 g (BMR = 5%). The BMDLs of TCd were 1.29–1.46 g (BMR = 10%) and 0.73–0.95 g (BMR = 5%). FCd and TCd are valuable markers for the predication of renal dysfunction induced by cadmium. The BMDLs of FCd were close to previous report in Japan and the BMDLs of TCd were lower than the critical standard previously reported, in particular at BMR of 5% which can be interpreted as representing the influence of smoking.

Effect of High Cadmium Loading on Performance of Free Water Surface Constructed Wetlands

This study was conducted to investigate the effect of high cadmium loading on the performance of free water surface constructed wetlands under different environmental conditions. Influents were prepared by mixing the synthetic wastewater with CdCl2 ∙ H2 O at concentrations of 5, 10, 25, and 50 mg∕L for each of the four simultaneous experiments during three runs. The performance of the wetland system was evaluated for three hydraulic retention times (HRT)—5, 7, and 10 days. Removal efficiencies of the soluble chemical oxygen demand were found to be in the range of 72–91% during the experimental period. The mean effluent cadmium concentrations varied between 0.17 and 12.73 mg∕L . The overall average cadmium removal efficiency during the three runs ranged between 75 and 97%. Most of the cadmium was accumulated in soil (56–76% of total influent cadmium). Of the total cadmium uptakes, about 14–23% of the total cadmium intake was accumulated in bulrush plants. The accumulation in soil and in plants increased wi...

CADMIUM BODY BURDEN IN RELATION TO CONCENTRATIONS IN SOIL AND VEGETABLES IN AN ENVIRONMENTALLY EXPOSED POPULATION

ISEE-122 Introduction: It is well known that cadmium exposure may cause kidney damage, initially detected as a tubular dysfunction, assessed by measuring certain proteins and enzymes in urine. Recent studies have indicated that the kidney damage may occur also at low levels of environmental cadmium exposure. Cadmium body burden can be estimated by cadmium in urine (U-Cd), and a Swedish study (the OSCAR study) has shown a dose-response relationship with a ten percent prevalence of tubular proteinuria at U-Cd = 1.0. Aim: However, the exposure pathways are less clear and the present study aimed to assess the relative impact of different pathways of exposure to cadmium on the absorbed dose and body burden in a subgroup of the OSCAR population, who lived near a battery plant. The study also aimed to evaluate the contribution of locally produced food (vegetables) to total dietary cadmium intake. Methods: Cadmium levels in urine were determined in 492 individuals living near a closed down battery factory in Sweden. For each individual we created an environmental exposure-index based on emission data from the factory and number of years living at various distances from the plant. These data, as well as information on dietary habits and confounders, were collected via questionnaires. Samples of soil, carrots and/or potatoes were collected from 38 gardens and analyzed for cadmium. Results: Cadmium concentrations in carrots, potatoes and soil were high in the area near the factory. Daily consumption of potatoes and vegetables grown in the vicinity of the battery plant was estimated to increase cadmium intake by 40-60%. Increased U-Cd concentrations of cadmium (over 1.0 nmol/mmol creatinine) were significantly associated with intake of homegrown vegetables, environmental cadmium-exposure-index, female gender, age above 30 years and smoking an amount equivalent to one pack of cigarettes for more than 10 years. No increased U-Cd levels were shown in non-smokers, who did not eat homegrown vegetables, suggesting negligible exposure via ambient air. Conclusion: The present study shows that consumption of locally grown food constituted an important exposure pathway in subjects living near a nickel-cadmium battery plant, whereas exposure via ambient air was less important.

The relation of individual cadmium concentration in urine with total cadmium intake in Kakehashi River basin, Japan

The aim of the present study was to clarify the relationship between urinary cadmium concentration (U-Cd) and total cadmium intake (T-Cd) based on individual data of Cd in urine. Morning urine specimens were collected from 198 persons (100 men with average age of 45.8 years and 98 women with average age of 50.7 years) living in the Kakehashi River basin in Ishikawa Prefecture, Japan. The method used to calculate T-Cd basically mirrored that used in our previous study. Correlation coefficients between U-Cd and T-Cd of 0.879 and 0.835 were obtained in men and women, respectively, with both values statistically significant. Therefore, T-Cd is confirmed to be a useful indicator for external Cd exposure even on the basis of individual data of U-Cd.

Cadmium intake of moose hunters in Finland from consumption of moose meat, liver and kidney

Although the average cadmium intake in Finland is about 10 μg day−1, some risk groups can be identified. This study assessed cadmium intake from the consumption of moose meat, liver and kidneys by moose hunters. Consumption data from a postal questionnaire were combined with a representative database on moose cadmium concentrations. Cadmium intakes were calculated as point estimates for all respondents (n = 711), for those consuming moose meat, liver and/or kidneys, and for the highest decile of those. Probabilistic modelling using the Monte Carlo technique was used to simulate the distribution of dietary cadmium exposure. Of the respondents, 69% consumed moose liver and only 23% moose kidneys. The consumption of moose liver or kidneys significantly increased cadmium intake, whereas moose meat (median consumption 17 kg year-1 person-1) contributed only slightly (0.16 μg day-1 person-1) to the daily total cadmium intake. In the simulation, 10% of the moose hunters had an intake of > 8.76 μg day-1 (14.6% of PTWI for a 60-kg person) from moose. Point estimates provided only a partial understanding of the potential exposure. Simulated distributions of intake were more useful in characterizing exposure. The study revealed that heavy users of moose organs have a relatively narrow safety margin from the levels of cadmium probably causing adverse health effects.

Total cadmium intake and mortality among residents in the Jinzu River Basin, Japan.

This study investigated the relationship between total cadmium intake and mortality among rural inhabitants of the Jinzu River Basin, Japan. A follow-up survey was conducted for 6,128 days on 3,236 inhabitants. The rural communities were divided into 2 groups, one with a total cadmium intake of < 2.0 gm and the other > or = 2.0 gm. Standardized mortality ratios and a Cox's proportional hazard model indicated mortality risk was greater in the > or = 2.0 gm group, compared with the < 2.0 gm group. In the Jinzu River Basin, a total cadmium intake > or = 2.0 gm exerts an adverse influence on life prognosis.

Association between total cadmium intake calculated from the cadmium concentration in household rice and mortality among inhabitants of the cadmium-polluted Jinzu River basin of Japan

A follow-up survey was conducted to investigate the relationship between total Cd intake and mortality in the Jinzu River basin for 6128 days among 757 inhabitants who ingested household rice. When the subjects were divided into two groups, standardized mortality ratios (SMRs) were 0.94 in men and 1.36 in women for the ≥2.0 g group and 0.68 in men and 0.29 in women for the <2.0 g group (significant in the women). Cox's hazard ratios for men, women, and men+women for the ≥2.0 g group relative to those in the <2.0 g group were 1.406, 3.955 and 1.950 (significant in the men+women). Using total Cd intake as a continuous variable, the hazard ratios were 1.045, 1.146 and 1.049 in men, women, and men+women (significant in the women), respectively. In the Jinzu River basin, increased total Cd intake appears to exert an adverse influence on life prognosis.

Cadmium in organs and tissues of horses slaughtered in Italy

The cadmium content of muscle, liver, kidney and blood samples from 62 horses slaughtered in Italy was investigated. Cadmium was determined by graphite furnace atomic absorption spectrometry (GFAAS) after wet digestion of the samples. The mean and median contents of all samples were (on a fresh weight basis) 75 and 41 μgkg-1 for muscle, 2.46 and 2.10 mgkg-1 for liver, 20.0 and 13.5 mgkg-1 for kidney. The cadmium level in blood samples was always below 6 μgl-1. The cadmium concentrations in muscle, liver and kidney were found to be related to the life span of the specimens and increased with age. Females exhibited higher levels than males, but this difference was significant only in the case of muscle tissue. The geographical origin was recognized as the main factor influencing the cadmium content of the equine specimens analysed. The differences between horses coming from the three main breeding countries considered in this study (Poland, Lithuania, Hungary) were marked and statistically significant. The average intake of cadmium from equine meat was estimated for the general population and for population groups resident in areas with high consumption of this food item. While the cadmium intake from equine meat for the average consumer accounts for about 1% of the total cadmium intake estimated for Italy, in the latter case the enhanced consumption of equine muscle is often accompanied with the consumption of substantial quantities of equine liver and this may lead to high cadmium intakes.

Risk assessment of cadmium exposure in Fort Resolution, Northwest Territories, Canada

The aim of this study is to investigate the cadmium (Cd) exposure level from traditional food in Fort Resolution, Northwest Territories. We used 24‐h dietary recalls and traditional food use frequency to obtain information on traditional food consumption, and analysed cadmium concentrations in traditional food. We also estimated total cadmium intake via market and traditional food, and cigarette smoking. Traditional food accounted for only 10% of the dietary energy. About 30 species of wildlife and plants were used. The most important foods in the community were moose, caribou, and whitefish. The range of cadmium concentrations measured was 0 to 1869 μg/g wet weight, with the lowest found in cranberry, and the highest in moose kidney. Cadmium concentrations in traditional food groups were comparable with those of Canadian market food. Highest levels of cadmium were found in the liver and kidney of caribou and moose. Cadmium intakes from traditional food estimated by dietary recall ranged from 001 to 1713 μg/g/day/person. Average cadmium intakes for women and men from traditional food were estimated to be 9% and 6% respectively, of the Provisional Tolerable Weekly Intake (PTWI, 400–500 μg) established by the World Health Organization. The average cadmium inhaled from cigarette smoking was 2.31 ± 1.00 μg/day/person. There was no difference between the total cadmium intakes of smokers and non‐smokers. The total cadmium intake via market and traditional food and cigarette smoking was 136.6 μg/ week, which was lower than the PTWI. However, about 20% of the population may consume caribou and moose organ more frequently than the others. The potential health effects on this sub‐population needs further clarification.

Dietary Intake of Cadmium and Lead among the General Population in Korea

This survey was conducted in Seoul, Pusan, Chunan, and Haman in Korea to clarify cadmium and lead burden in the general Korean populations in terms of dietary intake of cadmium and lead and the concentrations of the two metals in blood. People who participated in the study were 141 healthy nonsmoking women aged 21-56 years. Determination of cadmium and lead in 24-hr food duplicates and blood samples was carried out by graphite furnace atomic absorption spectrophotometry. The geometric means for the four sites in combination were 21.2 μg/day for dietary cadmium, 20.5 μg/day for dietary lead, 1.27 ng/ml for blood cadmium, and 44.3 ng/ml for blood lead. Cadmium intake from boiled rice accounted for 23% of total daily cadmium intake. The counterpart value for lead intake from boiled rice was 12%. Blood cadmium levels and dietary cadmium intake were lower and blood lead level and dietary lead intake were higher in Korean women than in Japanese women. The values for dietary cadmium are similar to, and the values for dietary lead are somewhat lower than, the levels reported from Europe and the United States. Dietary intake was the main source of cadmium exposure, whereas lead exposure was from both ambient air and foods in the Korean population.

Dose-response relationship between total cadmium intake and prevalence of renal dysfunction using general linear models.

To determine the maximum allowable intake limits for chronic dietary exposure to cadmium (Cd), the dose-response relationship between total Cd intake and prevalence of renal dysfunction was examined using general linear models considering the effect of age as a confounder. The target population comprised 1850 Cd-exposed and 294 non-exposed inhabitants of Ishikawa, Japan. They were divided into 96 subgroups by sex, age (four categories) cadmium concentrations in rice (three categories) and length of residence (four categories). As indicators of the cadmium-induced renal dysfunction, glucose, total protein, amino nitrogen, beta 2-microglobulin and metallothionein in urine were employed. General linear models were fitted statistically to the relationship among prevalence of renal dysfunction, sex, age and total Cd intake. Prevalence of abnormal urinary findings other than glucosuria had significant associations with total Cd intake. When total Cd intake corresponding to the mean prevalence of each abnormal urinary finding in the non-exposed subjects was calculated using general linear models, total Cd intakes corresponding to glucosuria, proteinuria, aminoaciduria (men only) and proteinuria with glucosuria were determined to be ca. 2.2-3.8 g and those corresponding to prevalence of metallothioneinuria were calculated as ca. 1.5-2.6 g. The low-molecular-weight protein in urine was confirmed to be a more sensitive indicator of renal dysfunction, and these total Cd intake values were close to those calculated previously by simple regression analysis, suggesting them to be reasonable values as the maximum allowable intake of Cd.

Dose-response relationship between total cadmium intake and β 2-microglobulinuria using logistic regression analysis

The dose-response relationship between total cadmium intake and β 2-microglobulinuria was investigated using logistic regression analysis in order to consider the effect of age on this association. The target population consisted of 1850 inhabitants of the cadmium-polluted Kakehashi River basin in Ishikawa prefecture, Japan. They were divided into 58 subgroups (27 in the men and 31 in the women) by four factors of sex, age, rice cadmium concentration and length of residence in cadmium-polluted areas. Logistic regression analysis was performed for this dose-response relationship, and both age and total cadmium intake were significantly associated with β 2-microglobulinuria. It was confirmed that total cadmium intake had a significant association with β 2-microglobulinuria, independent of the aging effect.

Dose-response relationship between total cadmium intake and metallothioneinuria using logistic regression analysis

The dose-response relationship for environmental cadmium exposure was assessed using logistic regression analysis. The prevalence of metallothioneinuria was employed as a response variable, while age and total cadmium intake, calculated from the average cadmium concentration in rice and duration of residence in the cadmium-polluted area, were used as explanatory variables. The target population comprised of 1843 cadmium-exposed and 240 non-exposed inhabitants of Ishikawa, Japan. The individuals were divided into 96 subgroups by sex, age (4 categories), cadmium concentrations in rice (3 categories) and length of residence in the polluted area (4 categories). Only total cadmium intake had a significant association with the prevalence of metallothioneinuria. In the non-exposed subjects total cadmium intakes corresponding to 2.5% prevalence of metallothioneinuria were calculated. Based on metallothionein levels expressed as either μg/l urine or μg/g creatinine, the total intakes were: 2.221 or 2.207 g in men and 2.365 or 0.319 g in women, respectively. Most of these values were similar to those reported by us previously, employing simple regression analysis. It is concluded, therefore, that a maximum allowable intake of about 2 g cadmium is a reasonable estimate for preventing the cadmium-induced renal dysfunction.

Lead and cadmium in some cereal products on the Finnish market 1990-91.

Lead and cadmium contents were determined in representatively collected (commercial mills, wholesalers) samples of rye flour, breakfast cereals, porridge flakes, muesli cereals and pasta products. The samples were digested by heating them overnight in concentrated HNO3. Lead and cadmium concentrations were determined by GFAAS using a platform and (NH4)H2PO4 as a matrix modifier. ARC/CL coded wheat flour and other reference materials (NBS 1567a, BCR no. 189, BCR no. 191) were employed for the analytical quality control. Lead and cadmium contents found in the above samples were generally much lower than the present tolerance limits in Finland (300 micrograms/kg and 100 micrograms/kg respectively). The mean cadmium and lead contents of rye flours studied were very low, being 9 micrograms/kg and 16 micrograms/kg respectively. The mean contents of lead and cadmium in wheat-based breakfast cereals were 22 and 42, in rye products 19 and 26, in oats 17 and 2, in maize products 11 and 18 and in rice products 31 and 10 micrograms/kg, respectively. The mean contents of lead and cadmium in muesli cereals were 34 and 27 micrograms/kg. Remarkably high cadmium contents were found in some pastas made from imported durum wheat. The mean cadmium content of all past products was 79 micrograms/kg with a range of 26-182 micrograms/kg. Lead contents were low, with a mean of 18 micrograms/kg, and a range of 8 to 66 micrograms/kg. Cereals contribute about 59% of the average total dietary cadmium intake in Finland. Nearly 60% of the total cereal consumption is wheat and 27% rye. Since rye has a lower cadmium content than wheat, rye is preferable to wheat. About 15% of lead is derived from cereals. As the total intake of heavy metals is very low in Finland, there is no need to alter cereal consumption.

Significance of urinary cadmium concentration in a Japanese population environmentally exposed to cadmium.

An epidemiological study was performed on 1,815 cadmium-exposed and 240 nonexposed inhabitants of the Kakehashi River basin in Ishikawa, Japan. The significance of urinary cadmium concentration as an indicator of internal dose in a general environment polluted by cadmium was investigated. The mean urinary cadmium concentration (Cd-U) increased in a dose-related manner when the subjects were classified according to the average cadmium concentration in their village rice and according to their period of residence in the polluted area. As total cadmium intake increased, Cd-U also increased, and strong correlations were found (r = .93 in men and r = .88 in women). Therefore, it was concluded that, on a group basis, Cd-U is a useful indicator of the internal dose of environmental cadmium exposure.

Dose-response relationship between dietary cadmium intake and metallothioneinuria in a population from a cadmium-polluted area of Japan

An epidemiology study to examine the dose-response relationship for environmental cadmium exposure was performed in 1843 cadmium-exposed and 240 non-exposed inhabitants of the Kakehashi River basin in Ishikawa, Japan. The average cadmium concentration in rice from each village was employed as an indicator of cadmium exposure and the individuals were grouped according to the length of residence in the polluted area. Metallothioneinuria was used as an index of renal tubular dysfunction produced by the chronic exposure to cadmium. A dose-related increase in metallothioneinuria was observed. he chronic total cadmium intake resulting in metallothioneimura in this population was calculated to be approximately 2 g for both men and women. The cumulative lifetime dose of 2 g cadmium over a 50-year period, means an average daily intake of 110 μg. Thus, these values may be regarded as the maximum allowable lifetime and daily intake limits, respectively for chronic dietary exposure to cadmium.

Cadmium content in rice and its daily intake in various countries

Man ingests cadmium daily from foods and beverages. The major source of cadmium intake is rice for rice eating countries. Cadmium in rice comes from soil via rice plant roots. Rice may thus be the best indicator for the environmental monitoring of cadmium especially in rice eating countries. It is also easy to sample, transport and conserve. Several recent surveys on cadmium content in rice and daily cadmium intake have been reported. However, little data are available on geographical differences in daily cadmium intake from rice. The tolerable weekly intake for cadmium as proposed by FAO/WHO is 400-500 micrograms/person or 57-71 micrograms/day/person weighing 70 kg. Ninety two percent of world rice production is from the Asia-Pacific region, from which samples were obtained for the present study. The following countries were included: India, China, Bangladesh, Thailand, Indonesia, Philippines, Japan, and Korea. This study was conducted to determine cadmium content in rice from the above countries and based on the data obtained, daily cadmium intake from rice and the total daily cadmium intake were calculated.