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1.
Selenium, copper, cadmium, and zinc concentrations were measured in mullet (Mugil cephalus) from the southern basin of Lake Macquarie, Australia, in 1997 to determine if improved ash-handling practices at an adjacent coal fired power station, implemented in 1995, had significantly lowered trace metal concentrations in mullet tissues. Mean muscle tissue concentrations of selenium (5.9 ± 0.7 μg/g dry mass), copper (3.6 ± 0.1 μg/g dry mass), and zinc (14 ± 1 μg/g dry mass) are lower than previously reported for mullet analyzed in 1993 (10 ± 2, 21 ± 3, 27 ± 3 μg/g dry mass, respectively). Cadmium concentrations in liver tissues increased from 2.3 ± 0.3 to 6 ± 2 μg/g dry mass. Significant intra-tissue correlations between metal concentrations were found for all tissues except muscle. Strong correlations of selenium, copper, and zinc concentrations were found in liver tissues, indicating a common primary source may exist for these metals, such as fly ash. All trace metals were found to have significant inter-tissue correlations, with strong correlations occurring for selenium between all tissues and for cadmium between all tissues except muscle. Regulation of copper, cadmium, and zinc appears to be occurring in muscle tissue. Selenium concentrations in mullet are still above levels considered to be of concern to human consumers. Trace metal concentrations are below that known to effect the health of fish. Mullet are directly exposed to trace metal concentrations as a result of feeding and the ingestion of contaminated sediment and detritus. Lower metal concentrations found in mullet tissues are attributed to the burial of highly contaminated sediment with material containing lower trace metal concentrations. Little of the variations in trace metal concentrations between mullet was explained by mass, gender, or age. Received: 20 August 2000/Accepted: 22 February 2001  相似文献   

2.
OBJECTIVE: To assess the phytate intake and molar ratios of phytate to calcium, iron and zinc in the diets of people in China. DESIGN: 2002 China Nationwide Nutrition and Health Survey is a cross-sectional nationwide representative survey on nutrition and health. The information on dietary intakes was collected using consecutive 3 days 24 h recall by trained interviewers. SUBJECTS: The data of 68 962 residents aged 2-101 years old from 132 counties were analyzed. RESULTS: The median daily dietary intake of phytate, calcium, iron and zinc were 1186, 338.1, 21.2 and 10.6 mg, respectively. Urban residents consumed less phytate (781 vs 1342 mg/day), more calcium (374.5 vs 324.1 mg/day) and comparable amounts of iron (21.1 vs 21.2 mg/day) and zinc (10.6 vs 10.6 mg/day) than their rural counterparts. A wide variation in phytate intake among residents from six areas was found, ranging from 648 to 1433 mg/day. The median molar ratios of phytate to calcium, iron, zinc and phytate x calcium/zinc were 0.22, 4.88, 11.1 and 89.0, respectively, with a large variation between urban and rural areas. The phytate:zinc molar ratios ranged from 6.2 to 14.2, whereas the phytate x calcium/zinc molar ratios were from 63.7 to 107.2. The proportion of subjects with ratios above the critical values of phytate to iron, phytate to calcium, phytate to zinc and phytate x calcium/zinc were 95.4, 43.7, 23.1 and 8.7%, respectively. All the phytate/mineral ratios of rural residents were higher than that of their urban counterparts. CONCLUSIONS: The dietary phytate intake of people in China was higher than those in Western developed countries and lower than those in developing countries. Phytate may impair the bioavailability of iron, calcium and zinc in the diets of people in China.  相似文献   

3.
Serum selenium as well as serum zinc, copper, magnesium, calcium and manganese were investigated in a control group of adult males and in 11 groups of patients in various disease states. Not only the change of each trace element but also the possible association between elements was studied in the various groups. All patients were fasting when sampled and studied only after the acute phase of the disease was corrected. Trace metal determinations were performed by atomic absorption spectrophometry (Mg, Ca, Cu, Zn) and by neutron activation analysis (Se, Mn). All patients showed low serum zinc when compared to controls. Cirrhotic patients had a low serum selenium level as well as low calcium, magnesium and zinc. Emphysemia and cancer patients had an elevated serum copper concentration while copper and manganese levels were elevated in congestive heart failure, infection and pschoses. To our knowledge this is the first time low serum selenium values have been demonstrated to be associated with the low serum zinc, calcium and magnesium levels found in cirrhotic patients.  相似文献   

4.
目的 通过检测0~12岁少儿血中钙、铁、锌、镁、铜、铅和镉水平,为预防疾病,科学合理的膳食提供理论依据。方法 收集灞桥区0~12岁少儿手指血样4 210例,进行微量元素和重金属元素的检测,分为4个年龄组,分别为0~1岁,1~3岁,3~7岁,7~12岁,进行资料收集和统计分析。结果 不同年龄段儿童的微量元素和重金属元素的平均值之间存在统计学差异(P<0.05);0~12岁儿童钙、铁和锌元素的总体缺乏率分别为24.94%,19.19%和13.85%,差异有统计学意义(P<0.05);镁和铜元素的缺乏率在不同年龄段中无统计学差异;未见铅镉水平超标;男童和女童在钙、铁、锌元素的缺乏率上存在差异,镁和铜元素在男女童之间无明显差异。结论 灞桥区儿童钙、铁缺乏较为明显,锌其次,铜和镁元素基本不缺乏。应提高家长和民众对微量元素和重金属元素的认识,同时发现微量元素的缺乏,应该尽早纠正,科学补充微量元素。  相似文献   

5.
The literature indicates that phytate:zinc and phytate X calcium:zinc millimolar ratios of a diet may provide useful indexes of the bioavailability of dietary zinc. However, there is little information on the phytate:zinc and phytate X calcium:zinc millimolar ratios for total human diets. We have therefore determined the phytate:zinc and phytate X calcium:zinc millimolar ratios of self-selected diets of 29 American omnivores, 23 American vegetarians, 30 Asian Indian immigrant vegetarians, and 26 Nepalese lactating vegetarians. Criteria for selection of subjects were: good health, no extreme dietary habits, and no intake of nutrient supplements. According to the limited literature, the suggested critical values for phytate:zinc and phytate X calcium:zinc millimolar ratios in animal diets and retrospective calculations from human diets are greater than 10 and greater than 200, respectively. The mean phytate:zinc and phytate X calcium:zinc millimolar ratios of American omnivorous diets in the present study were less than 10 and 200, respectively. Confirmation of the critical molar ratios as indexes of the bioavailability of zinc in human diets has not been established by experimentation. However, if the data from animal studies are applicable to human diets, the present study suggests that phytate has little influence on zinc bioavailability of most American diets. In contrast, the mean phytate:zinc and phytate X calcium:zinc millimolar ratios of all vegetarian diets were above the proposed critical levels. Those data, therefore, suggest that phytate might increase the risk of impaired zinc bioavailability for vegetarians consuming a relatively high level of calcium.  相似文献   

6.
Heptageniid mayfly nymphs have been suggested as sensitive indicators of metal contamination in streams based on biomonitoring studies, experimentation in situ, and experimentation in microcosm. Laboratory tests were conducted to evaluate the sensitivity of Rhithrogena hageni, a heptageniid mayfly, to waterborne copper, cadmium, and zinc. Tests were conducted with soft water (hardness = 40–50 mg/L) at about 12°C. Toxicity endpoints were survival and moulting (%/day). Median 96 hr lethal concentrations were 0.137, 10.5, and 50.5 mg/L for copper, cadmium and zinc, respectively. The average daily moulting rate of survivors significantly decreased after exposure to these metals in solution.  相似文献   

7.
The availability of micronutrients from sweetpotato-based complementary foods (CFs): oven-toasted and roller-dried ComFa, and from a maize-based infant food, enriched Weanimix, was compared using phytate/mineral molar ratios, polyphenols and β-carotene levels. The phytate/calcium, iron and zinc molar ratios of approximately 0.17, 1 and 15 predict better absorption of calcium, iron and zinc respectively. Generally, the sweetpotato-based CFs had at least half the phytate/mineral ratios of enriched Weanimix. The phytate/iron ratio in both the sweetpotato- and the maize-based CFs was greater than 1. Only the ComFa formulations had phytate/zinc ratio lower than 15. The level of polyphenol (iron inhibitor) was similar for the formulations. Only the sweetpotato-based CFs contained measurable levels of β-carotene, a possible iron enhancer. The lower phytate/mineral ratios and the β-carotene level of the sweetpotato-based CFs suggest that calcium, iron and zinc absorption could be better from them than from the maize-based infant food.  相似文献   

8.
BACKGROUND: Although soy formulas have been designed to meet the nutrient requirements of human infants, they also contain phytate, which may negatively affect trace element absorption. OBJECTIVE: We evaluated the effect of removing phytate on zinc and copper absorption and status in infant rhesus monkeys and suckling rat pups and evaluated differences between intact and partially hydrolyzed soy protein. DESIGN: In monkeys, regular and low-phytate soy formulas were fed exclusively for 4 mo and whole-body absorption and retention of 65Zn, 67Cu, 59Fe, 54Mn, and 47Ca were determined at different time points with a whole-body counter. Subsequently, zinc and copper absorption from several human infant formulas and the effect of phytate concentration were evaluated in suckling rat pups by using 65Zn and 64Cu. Finally, infant rhesus monkeys were fed low-phytate formulas with intact or hydrolyzed soy protein for 4 mo and plasma zinc and copper were measured monthly. RESULTS: In the first monkey study, zinc absorption at 1 mo was higher from low-phytate soy formula (36%) than from regular soy formula (22%), whereas there was no significant difference between groups in the absorption of other minerals. Plasma copper was significantly lower in monkeys fed low-phytate soy formula from 2 to 4 mo. In rat pups, zinc absorption was significantly higher from low-phytate soy formula (78%) than from regular soy formula (51%) and hydrolysis of the protein had no significant effect. Phytate content or protein hydrolysis did not significantly affect copper absorption. In the second monkey study, plasma copper concentrations were highest in monkeys fed the low-phytate, hydrolyzed-protein soy formula. CONCLUSION: Reducing the phytate content and partially hydrolyzing the protein in soy formula had a beneficial effect on zinc and copper absorption and status in infant rhesus monkeys.  相似文献   

9.
Balance studies of cadmium, copper, manganese, and zine were carried out under constant dietary conditions in eight adult males during two calcium intake levels of 200 and 800 mg/day and in an additional single case during a calcium intake of 1500 mg/day. The dietary content and the excretions of these elements in urine and stool were determined. The mean dietary content of cadmium was 32.9 micrograms/day, of copper 1020 micrograms/day, of manganese 2130 micrograms/day, and of zinc 12.4 mg/day. The ratio of the fecal/urinary cadmium excretion was approximately 1.5 and the main pathway of excretion of the other three elements was via the intestine, while the urinary excretions were very low. The different trace element balances were either slightly negative or in equilibrium, except that the zinc balances was positive in 50% of the cases. All balances should be considered maximal values, as the losses in sweat were not determined. The calcium intake level had little effect on the excretion and retention of these trace elements.  相似文献   

10.
Concentrations of zinc, copper, and cadmium were determined in soil and liver, kidney, bone and stomach contents of deer mice (Peromyscus maniculatus) from two sites near an abandoned mine and one control site, on Vancouver Island, British Columbia, Canada. Soil concentrations of copper were significantly elevated at the mine and off site vs the reference site. In contrast, there was no difference in soil cadmium and zinc concentrations between the mine and reference site. Concentrations of copper, cadmium and zinc in livers of mice from the mine site were significantly elevated relative to the reference and off site locations. Cadmium kidney concentrations tended to be greater in mice from the mine versus the off site and reference site. No differences in bone cadmium, copper and zinc and, kidney copper and zinc concentrations were noted among mice from the three locations. Diet of mice from mine and off sites contained significantly greater copper concentrations than the reference population; no differences in cadmium or zinc diet concentrations in mice from the three sites were noted. Comparison of ratios of metal concentrations in diet:soil and concentrations in liver:soil suggest that for zinc and copper, soil and diet are of equal importance as a source of metal contamination to these mice. In contrast, cadmium diet:soil and cadmium liver:soil ratios were much greater than one indicative of bioconcentration of cadmium from soil to diet and from soil to liver. For assessing routes of metal exposure, in this case for deer mice inhabiting an abandoned mine site, for copper and zinc, soil will most likely be indicative of exposure conditions. In contrast, concentrations of cadmium in diet will be more representative of amounts that the animal is potentially ingesting. Of further importance is that relative to reference sites, mice inhabiting an abandoned copper mine site have significantly elevated tissue levels of copper. This is turn will provide a route of metal exposure to canivorous birds such as owls and hawks. The toxicological significance of this exposure to birds of prey has yet to be assessed adequately.  相似文献   

11.
To determine the influence of wide variations in dietary levels of calcium, zinc and phytic acid (as sodium phytate) on growth and cataract incidence, juvenile chinook salmon held at 10-11 degrees C were fed daily to satiation for 105 d one of nine purified diets containing one of three levels (grams/kilogram) of calcium (averaged 4.8, 17.7, 50.2), zinc (averaged 0.05, 0.15, 0.39) and phytic acid (1.62, 6.46, 25.8). Diets were formulated to have a calcium-phosphorus ratio of close to unity when considering phosphorus sources other than sodium phytate. High dietary phytic acid concentration (25.8 g/kg) depressed chinook salmon growth, food and protein conversion [protein efficiency ratio (PER)] and thyroid function, increased mortality, promoted cataract formation (zinc at 0.05 g/kg) and induced anomalies in pyloric cecal structure. Calcium at 51 g/kg (or phosphorus) exacerbated the effects of high dietary phytate and low dietary zinc on cataract incidence. Moreover, high dietary levels of calcium (48-51 g/kg) coupled with phosphorus significantly impaired the growth and appetite of low phytic acid (1.62 g/kg) groups and led to nephrocalcinosis in low and high phytic acid groups. Plasma zinc levels were directly related to dietary zinc concentration and inversely related to dietary phytic acid level. Calcium (51 g/kg) and/or phosphorus reduced zinc bioavailability when the diet concurrently contained 0.05 g zinc and 25.8 g of phytic acid per kilogram. It is concluded that zinc is essential for normal eye development in juvenile chinook salmon. Further, zinc deficiency could not be induced in chinook salmon fed diets with high ratios of calcium (or phosphorus) to zinc alone. This required the simultaneous presence of a strong mineral (zinc)-binding agent.  相似文献   

12.
Central composite designs were used to develop surface response relationships for predicting the chronic toxicity of mixtures of zinc, cadmium, copper, and lead to the potworm Enchytraeus albidus. Surface response relationships were obtained for all binary mixtures of zinc, cadmium, copper, and lead as well as for mixtures with all four metals. For the binary mixture of zinc and cadmium, this approach and the toxit unit approach gave similar results. However, with the toxit unit approach no such surface response models can be developed. The experimental results indicated that effect predictions based on the concentration addition model were always higher than those obtained with the independent action model. The observed effect was lower than the effect predicted by the concentration addition model for all metal mixtures. Therefore it can be concluded that the concentration addition model represents a reasonable worst-case scenario for the risk assessment of metal mixtures in terrestrial ecosystems.  相似文献   

13.
The present study was performed to assess the effect of short-term ethanol administration on cadmium retention and accumulation as well as on bioelement metabolism (zinc, copper, calcium, and magnesium) in rats exposed to an aqueous solution of cadmium chloride for 8 weeks. Intoxication with cadmium led to accumulation of this toxic metal, particularly in the liver and kidney, which was linked to metallothionein synthesis as well as to a disturbance in the metabolism of zinc, copper, and calcium. These effects were dependent on the level of exposure. The administration of ethanol in the final phase of cadmium treatment increased cadmium retention and accumulation in the body with simultaneous elevation in liver and kidney metallothionein concentration. Ethanol alone or with cadmium caused or intensified the cadmium-induced changes in metabolism of zinc and copper. Calcium metabolism disturbed by cadmium was not influenced by ethanol. Neither agents had any effect on magnesium metabolism. We conclude that even short-term ethanol consumption in conditions of exposure to cadmium can increase this heavy metal body burden and lead to more serious disturbances in metabolism of important elements such as zinc and copper. Cadmium- and ethanol-induced changes in the homeostasis of these microelements are probably connected with the ability of both xenobiotics to cause metallothionein induction.  相似文献   

14.
500例城市学前儿童血清钙锌铜铁含量调查   总被引:4,自引:1,他引:3  
目的 :测定城市学前儿童血清钙、铁、锌、铜的含量以便了解必需元素的营养水平。方法 :采用化学比色法 ,在日立 71 70全自动生化分析仪上测定。结果 :钙、锌、铜、铁的含量分别为2 .38± 0 .1 5 mmol/L、1 5 .86± 3.2 4、1 5 .2 0± 4.5 6、1 7.73± 4.1 1 μmol/L;大多数结果均在正常参考范围内 ( x± 2 s)。轻度缺乏的比例分别为 4.4%、1 .6%、0 %、5 .6%。结论 :大多数城市学前儿童血清中钙、锌、铜、铁的水平正常 ,仅有很少数儿童血清中钙、锌、铁轻度缺乏  相似文献   

15.
Twenty-two rabbits were given repeated subcutaneous injection of cadmium chloride. The cumulative cadmium dose given ranged from 13 to 214 mumole/kg body weight. Five rabbits served as controls. The treatment resulted in cadmium concentrations in kidney cortex that ranged from 0.3 to 3.2 mmole Cd/kg and a subsequent production of metallothionein. The molar ratio of cadmium, zinc, and copper in metallothionein fractions from kidneys with different concentrations of cadmium was determined. At low concentrations of cadmium in rabbit kidneys, zinc was the dominating metal bound to metallothionein (70-90%). At high concentrations of cadmium in kidneys, cadmium was the dominating metal in metallothionein. Evidence of kidney toxicity, in the form of beta2-microglobulinuria, was seen when cadmium constituted 85% of the metal ions recovered from metallothionein fractions. The remaining 15% was zinc. This indicates that at most six of the seven metal-binding sites in mammalian metallothionein are occupied by cadmium and that the remaining site is occupied by zinc. Our data provide further support for the hypothesis that chronic cadmium nephrotoxicity develops when there is a lack of metal-binding sites available for cadmium in metallothionein.  相似文献   

16.
Oysters, Crassostrea rhizophorae, were reciprocally transplanted to two different sites: a contaminated site in the Cotegipe Channel at Aratu Bay and an uncontaminated site at Cacha-Prego, inside and outside of Todos os Santos Bay (Brazil), respectively. Trace metal accumulation was measured after 0, 15, 30, and 60 days of exposure at the contaminated site. Oysters transplanted for 60 days from the clean to the contaminated site had accumulated cadmium and lead to similar concentrations as found in the native oysters. They had also accumulated copper and zinc, but to lower levels compared to native specimens. Elimination experiments were carried out by transplanting oysters in the reverse direction. After 30 days, concentrations of cadmium and lead had decreased to levels comparable to those in the native specimen, whereas concentrations of copper and zinc did not diminish. A second elimination experiment, bringing back to Cacha-Prego oysters that had been exposed 60 days at Cotegipe Channel, indicated stronger decreases of copper and lead, but no clear changes of cadmium and zinc concentrations. The accumulation experiment with C. rhizophorae is useful to estimate trace metal bioavailability and changes in concentrations as a function of time at the contaminated site. The different results of elimination experiments in the uncontaminated site suggest different degrees of trace metal fixation after long-term and short-term accumulation periods. Received: 1 July 1998/Accepted: 12 May 1999  相似文献   

17.
Chlorella pyrenoidosa cultures grown at pH 7 in the presence of 0, 0.25, 0.50, and 1.00 mg of Cd/liter had doubling times of 11, 21, 22, and 35 hours, respectively, whereas similarly exposed cultures grown at pH 8 had doubling times of 11, 16, 17, and 25 hours, respectively. C. pyrenoidosa is capable of concentrating cadmium, and the amount accumulated is directly proportional to the concentration of metal present initially and is dependent upon the pH of the medium. No accumulation occurs in the dark, at 4°C, or in dead cells. Cadmium accumulation is not affected by the concentration of calcium, magnesium, molybdenum, copper, zinc, or cobalt in the growth medium, whereas a level of manganese equal to 0.20 mg/liter completely blocks cadmium accumulation; iron may also play a role in regulating cadmium accumulation. Cells which had accumulated cadmium could still fix atmospheric CO2, albeit at reduced rates; O2 evolution was also inhibited, but to a lesser extent. The ability of C. pyrenoidosa to accumulate large concentrations of cadmium before showing adverse effects may be related to the presence of cadmium-sequestering agent(s) within the cell. The concentration of cadmium by C. pyrenoidosa could pose a hazard to the freshwater food chain.  相似文献   

18.
During August–November 1992 and August 1993, bed sediment and fish liver were sampled in the South Platte River Basin and analyzed for 45 elements in bed sediment and 19 elements in fish liver. The results for aluminum, arsenic, cadmium, chromium, copper, iron, lead, manganese, selenium, silver, uranium, and zinc are presented here. All 12 trace elements were detected in bed sediment, but not all were detected in fish liver or in all species of fish. A background concentration of trace elements in bed sediment was calculated using the cumulative frequency curves of trace element concentrations at all sites. Arsenic, cadmium, copper, lead, manganese, silver, uranium, and zinc concentrations were greater than background concentrations at sites in mining areas or at sites that have natural sources of these elements. Trace element concentrations in fish liver generally did not follow the same patterns as concentrations in bed sediment, although concentrations of aluminum and cadmium were higher in fish liver collected at mountain sites that had been disturbed by mining. Concentrations of aluminum, arsenic, cadmium, chromium, copper, iron, lead, silver, and zinc increased in bed sediments in urban areas. Iron, silver, and zinc concentrations in fish liver also increased in urban areas. Concentrations of cadmium, copper, silver, and zinc in fish liver increased in the agricultural areas of the basin. Downstream changes in trace element concentrations may be the result of geological changes in addition to changes in land use along the river. Received: 5 April 1996/Revised: 27 July 1996  相似文献   

19.
目的:探讨深圳市早孕妇女微量元素含量,指导孕妇合理补充。方法:应用元素分析仪,监测105例早孕妇女血清微量元素铜、锌、铁、钙、镁、铅、镉等含量作为研究组,选择同期正常妇女105例作为对照组,对照分析两组微量元素缺乏的种类及发生率。结果:研究组铜、锌平均含量高于对照组,钙、镁、铁则低于对照组;研究组和对照组缺锌发生率均较高,达21.90%和23.81%;研究组缺铁发生率明显高于对照组、缺铜的发生率低于对照组。结论:深圳市早孕妇女以缺铁、缺锌、缺铜为主,缺钙者不多,通过饮食补充微量元素是最安全的有效途径。  相似文献   

20.
The content of zinc, iron, calcium and phytate in the 16 most consumed foods from 5 villages in a tropical rural area of Bolivia was analyzed. The food items were selected according to a completed food frequency questionnaire. Minerals were analyzed by atomic absorption and phytates by HPIC chromatography. The molar ratios of phytate:mineral are presented as indication of the mineral bioavailability. Within the analyzed food, quinoa is a potential source of minerals: zinc 3.65, iron 5.40 and calcium 176 mg/100 g; however, it also has the highest content of phytate 2060 mg/100 g. Cereals and legumes showed high concentration of phytates (from 142 to 2070 mg/100 g), roots and tubers have lower concentrations (from 77 to 427 mg/100 g). In general, both phytate contents and molar ratios Phy:Zn (phytate:zinc), Phy:Fe (phytate:iron) and Phy:Ca (phytate:calcium) in most of the analyzed foods were at levels likely to inhibit the absorption of these minerals. Significant positive associations (p < 0.01) were found between the level of phytate and minerals in food, for zinc (r = 0.714), iron (r = 0.650) and calcium (r = 0.415). The results compared to data from USA or from Bolivia showed some discrepancies, confirming the need for more reliable data for dietary evaluations and interventions.  相似文献   

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