Soft-tissue accumulation of lead in the blue tilapia,Oreochromis aureus (steindachner), and the modifying effects of cadmium and mercury

The interaction of mercury and cadmium with lead was investigated by exposingOreochromis aureus to two heavy metals simulataneously. The chronic accumulation prolife of lead was determined by analyzing the liver, brain, gill filaments, intestine, caudal muscle, spleen, trunk kidney, and gonads following exposure to lead alone and in mixtures with mercury and cadmium. Nominal exposure concentrations of lead were 0.05, 0.10, 0.50, and 1.00 mg/L. Mixtures of lead (0.50 or 0.05 mg/L) with cadmium (0.05 mg/L) and lead (0.50 or 0.05 mg/L) with mercury (0.05 mg/L) were also used. Following 140 d of exposure to lead, the highest concentrations of lead consistently accumulated in the trunk kidney. The concentration of lead in the kidney was decreased by coexposure to mercury or cadmium, but increased in the muscle and liver. Under all exposure regimes, the median concentration of lead in the muscle exceeded safety levels recommended for human consumption. In a food fish, such asO. aureus, a knowledge of toxic metal accumulation patterns is of great importance.     

Comparative and interactive effects of mercury, cadmium and lead on tissue GSH levels in Oreochromis aureus (Steindachner): implications for monitoring heavy metal pollution

The effects of 45 days exposure to mercury, cadmium and lead on tissue GSH levels were studied in Oreochromis aureus (Steindachner). Liver, brain, gill filaments, intestine and caudal muscle were assayed after exposure to these heavy metals singly, or in combination. Significant increases in intestinal GSH concentrations consistently occurred after exposure to mixtures of heavy metals. Exposure to cadmium or lead did not change hepatic GSH levels, while exposure to two different concentrations of mercury caused significant increases in hepatic GSH.     

Spatial Distribution and Correlative Study of the Total and the Available Heavy Metals in Soil From a Typical Lead Smelting Area,China

Representative soil samples (n = 453) were collected from a lead smelting area in central China. The total and the available contents of several hazardous elements, including lead, cadmium, arsenic and mercury were determined. Inorganic acid were used for the pretreatment of the total element analysis. DTPA (Diethylene triamine pentacetate acid) digestion, an effective pretreatment procedure for the biological availability assessment of heavy metals, was used for bio-available assessment in this study. Graphite furnace atomic absorption spectrometry (GFAAS), inductively coupled plasma-optical emission spectrometer (ICP-OES) and inductively coupled plasma-mass spectrometry (ICP-MS) were employed for the instrumental analysis. The results indicated that the soil samples were seriously polluted by mercury, arsenic, lead and cadmium around the smelting factories, comparing to many other cities in China. Spatial distributions of the metal contents were then illustrated with maps. For 220 samples in pollution areas, average bio-effectiveness rates of cadmium, lead, mercury and arsenic in soils were 25.9%, 17.2%, 0.58% and 0.11%, respectively. The relationships of the total and the available contents of metals were investigated, among which lead and cadmium were found to can be expressed as linear and power function. These equations were tested inversely and further verified by the data from six randomly selected sites. The results will be helpful to assess the bioavailable contents of lead and cadmium fast and accurately only by the total contents and functional calculation in similar study.     

Report on the levels of cadmium, lead, and mercury in imported rice grain samples

In an attempt to know whether highly consumed food might contribute to metal exposure, we analyzed cadmium, lead, and mercury in 27 rice grain samples commonly consumed in Saudi Arabia by atomic absorption spectrometry after acid digestion. The mean concentrations and ranges of cadmium, lead, and mercury in tested rice samples were 20.261 (range <DL-178.026 μg/kg), 134.819 (range 23.1–1529.0 μg/kg), and 3.186 (range <DL-43.573 μg/kg), respectively. The results showed high concentrations of metals and in some cases exceeded the Provisional Tolerance Weekly Intake (PTWI) recommended by FAO/WHO. It was also noted that different rice grain samples had varying concentrations of these metals. Because the bulk of literature warns against the cumulative effects of prolonged heavy metal exposure, regular consumption of rice by local populations might pose potential health problems.     

The effects of age and sex on seven elements of Sprague-Dawley rat organs

This study reports age-related changes in 7 element (iron, copper, zinc, manganese, mercury, cadmium and lead) concentrations in the liver, kidney and brain of male and female Sprague-Dawley rats from 1 to 364 days of age. Atomic absorption spectrometry was used for the measurements. Copper, mercury and cadmium in the male and female kidneys increased from weaning until 127 days of age, as did iron concentrations in the female liver and kidney. After 127 days, especially, the copper concentration in the female kidney and cadmium concentration in the male and female kidney increased further. Consistent and statistically significant (P less than 0.05) sex differences in element concentrations were found for three elements (iron, copper and zinc). Except for the zinc concentration in the liver from 50 to 72 days, iron (in liver and kidney), zinc (in kidney) and copper (in liver, kidney and brain) concentrations in female rats during the adult stage, were all higher than those of male rats. Isolated differences for other elements (manganese, mercury and cadmium) were also found. The data will be helpful when setting up long-term animal investigations of the biological effect of elements.     

Blood and placental concentrations of cadmium, lead, and mercury in mothers and their newborns

Placental transfer of cadmium, lead and mercury was studied under the conditions of environmental exposures of pregnant women to these heavy metals. Fifty pregnant women from industrial area and a similar control group from a semirural area were examined. Cadmium, lead and total mercury levels were determined in maternal erythrocytes and plasma, in placenta, and in erythrocytes and plasma of umbilical cord blood using atomic absorption spectrophotometry. Except for the cadmium plasma concentration in the control area, levels of the three metals were higher in maternal than in cord blood. The mean plasma values (arithmetic mean) of cadmium, lead, and mercury in industrial area were 0.53, 6.37, and 0.37 micrograms.100 ml-1 in maternal blood and 0.30, 4.82, and 0.31 micrograms.100 ml-1 in cord blood. Highest values of the correlation coefficients were found between the cadmium and mercury concentrations in maternal and cord blood erythrocytes. No striking effect of the place of residence of pregnant women on the heavy metal concentrations in biological materials could be found.     

Biological monitoring,by in vivo XRF measurements,of occupational exposure to lead,cadmium, and mercury

In vivo X-ray fluorescence (XRF) techniques were used for biological monitoring of lead, cadmium, and mercury. Lead accumulates in bone, the level of which may thus be used for monitoring of exposure. However, there was no close association between lead levels in bone and exposure time, partly because of differences in exposure patterns and partly, probably, because of variations in the toxicokinetics of lead. There are at least two separate bone lead compartments. The average over-all half-time is probably 5–10 yr. The finger bone level may be an index of the lead status of the total skeleton. In lead workers, the mobilization of bone lead causes an “internal” lead exposure and affects the blood lead level considerably. In cadmium workers, in vivo XRF is a sensitive and risk-free method for assessment of accumulation in kidney cortex, the critical tissue as to toxic effects; workers displayed increased levels. However, there was no clear association with duration and intensity of exposure, cadmium levels in urine, or microglobulinuria. Determinations of kidney cadmium may add important information on the state of accumulation and, thus, risk of kidney damage. Workers exposed to elemental mercury vapor, as well as fishermen exposed to methyl mercury, had mercury levels in bone below the detection limit of the XRF method.     

Hair Toxic Element Content in Adult Men and Women in Relation to Body Mass Index

The primary objective of the current study was to estimate the hair toxic metal content in adults in relation to body mass index. A total of 1,229 persons including 719 women and 510 men were examined. All subjects were divided into two age groups: 1 and 2 periods of adulthood. All men and women were also subdivided into groups in relation to their values of body mass index (BMI): underweight, normal weight, overweight and obese. Hair aluminium (Al), beryllium (Be), cadmium (Cd), mercury (Hg), lead (Pb) and tin (Sn) content was evaluated using mass spectrometry with inductively coupled plasma. It has been shown that increase in body weight is accompanied by elevated hair cadmium content in women. At the same time, no significant alteration of hair cadmium concentration was observed in males. Higher values of scalp hair mercury and lead content were observed in men and women with increased body mass index independently of their age. BMI-related elevation of hair tin content was registered only in men of the first period of adulthood. A significant correlation between hair metal content and the values of BMI was observed for mercury independently of the gender of the subjects, whereas BMI values correlated significantly with hair cadmium levels in women and lead and tin levels in men. It has been also estimated that hair cadmium, mercury and lead levels in men exceed the respective values in women.     

Body Fat Percentage and Hemoglobin Levels Are Related to Blood Lead, Cadmium, and Mercury Concentrations in a Korean Adult Population (KNHANES 2008–2010)

Body stores of lead, cadmium, and mercury are determined by the levels in the circulation, and their levels in blood may be related to hemoglobin levels and their absorption by soft tissue and bone. We investigated the association of body fat percentage, hemoglobin levels, and nutrient intakes with the blood concentrations of lead, cadmium, and mercury in a Korean adult population. This study was based on data from the 2008–2010 Korean National Health and Nutritional Examination Survey (n?=?4,522, aged ≥20 years), which examined nutritional, biochemical, and health-related parameters. A multiple regression analysis after controlling for covariates of age, body mass index, residence area, education level, smoking and drinking status, and bone mineral density for men, with menopausal status added for women in addition to covariates for men indicated that blood lead and mercury levels were negatively associated with body fat percentage only in men, and blood lead, cadmium, and mercury levels were positively related to hemoglobin levels in both genders. Additionally, blood lead levels were negatively associated with fat and carbohydrate intake in both men and women but blood mercury levels were only in men, but not women. Sodium intake was a positive predictor of blood lead levels in both genders but was a positive predictor of blood cadmium levels only in men. In conclusion, body fat percentage and hemoglobin levels need to be recognized as confounding factors when considering blood levels of lead, cadmium and mercury as biomarkers for their exposure. Fat, carbohydrates and sodium intakes are also associated with heavy metal levels in the circulation.     

Detoxification of mercury, cadmium, and lead in Klebsiella aerogenes NCTC 418 growing in continuous culture

Klebsiella aerogenes NCTC 418 growing in the presence of cadmium under glucose-, sulfate-, or phosphate-limited conditions in continuous culture exhibited sulfide formation and Pi accumulation as the only demonstrable detoxification mechanisms. In the presence of mercury under similar conditions only HgS formation could be confirmed, by an increased sensitivity to mercury under sulfate-limited conditions, among others. The fact that the cells were most sensitive to cadmium under conditions of phosphate limitation and most sensitive to mercury under conditions of sulfate limitation led to the hypothesis that these inorganic detoxification mechanisms generally depended on a kind of "facilitated precipitation". The process was coined thus because heavy metals were probably accumulated and precipitated near the cell perimeter due to the relatively high local concentrations of sulfide and phosphate there. Depending on the growth-limiting nutrient, mercury proved to be 25-fold (phosphate limitation), 75-fold (glycerol limitation), or 150-fold (sulfate limitation) more toxic than cadmium to this organism. In the presence of lead, PbS formation was suggested. Since no other detoxification mechanisms were detected, for example, rendering heavy metal ions innocuous as metallo-organic compounds, it was concluded that formation of heavy metal precipitates is crucially important to this organism. In addition, it was observed that several components of a defined mineral medium were able to reduce mercuric ions to elemental mercury. This abiotic mercury volatilization was studied in detail, and its general and environmental implications are discussed.     

Detoxification of mercury, cadmium, and lead in Klebsiella aerogenes NCTC 418 growing in continuous culture.

Klebsiella aerogenes NCTC 418 growing in the presence of cadmium under glucose-, sulfate-, or phosphate-limited conditions in continuous culture exhibited sulfide formation and Pi accumulation as the only demonstrable detoxification mechanisms. In the presence of mercury under similar conditions only HgS formation could be confirmed, by an increased sensitivity to mercury under sulfate-limited conditions, among others. The fact that the cells were most sensitive to cadmium under conditions of phosphate limitation and most sensitive to mercury under conditions of sulfate limitation led to the hypothesis that these inorganic detoxification mechanisms generally depended on a kind of "facilitated precipitation". The process was coined thus because heavy metals were probably accumulated and precipitated near the cell perimeter due to the relatively high local concentrations of sulfide and phosphate there. Depending on the growth-limiting nutrient, mercury proved to be 25-fold (phosphate limitation), 75-fold (glycerol limitation), or 150-fold (sulfate limitation) more toxic than cadmium to this organism. In the presence of lead, PbS formation was suggested. Since no other detoxification mechanisms were detected, for example, rendering heavy metal ions innocuous as metallo-organic compounds, it was concluded that formation of heavy metal precipitates is crucially important to this organism. In addition, it was observed that several components of a defined mineral medium were able to reduce mercuric ions to elemental mercury. This abiotic mercury volatilization was studied in detail, and its general and environmental implications are discussed.     

Influence of silver,mercury, lead,cadmium, and selenium on glutathione peroxidase and transferase activities in rats

At the levels used in the experiments, mercury and silver significantly depressed the activity of glutathione peroxidase (assayed with either H₂O₂ or cumene-OOH) in rat tissues, whereas cadmium or lead had no effect on this activity. The most pronounced effects of mercury and silver on glutathione peroxidase were found in the liver and kidneys, with much less effect in the testes and erythrocytes. Similar trends for the effects of these metals were noted for tissue selenium levels. Silver and mercury significantly depressed the selenium concentrations, but cadmium and lead had no effect upon the selenium levels. Mercury and silver had no effect upon the activity of glutathione transferase in liver and testes, but mercury caused a significant initial increase of its activity in the kidneys. At no time did silver have any significant effect on its activity in this organ.     

Alterations in plasma sodium and potassium levels following chronic oral ingestion of lead, mercury and cadmium in male albino rats.

Adult male albino rats were orally administered 0, 25, 50 and 100 ppm of lead nitrate, mercuric chloride and cadmium chloride for 60, 120 and 180 days. The plasma sodium levels were decreased in rats exposed to varying doses of lead and mercury up to 180 days, while animals which consumed cadmium chloride showed an increase in sodium levels. In lead and mercury treated animals, plasma potassium levels were increased up to 180 days. The levels were decreased in cadmium exposed rats. These observations suggest that chronic exposure to these heavy metals considerably influences plasma sodium and potassium levels depending on the dose and duration of exposure.     

Heavy metal concentrations in the breast milk of Saudi women

Lead, cadmium, and mercury concentrations were determined in breast milk of Saudi lactating mothers from Riyadh and Al-Ehssa regions in Saudi Arabia who were not occupationally exposed. The mean levels for cadmium, lead, and mercury were 1.732 μg/L, 31.671 μg/L, and 3.100 μg/L, respectively. In contrast to mercury, mothers living in the Al-Ehssa region had significantly higher cadmium and lead concentrations in their breast milk than those in the Riyadh region. The estimated weekly intakes of cadmium, lead, and mercury of breast-fed infants in this study were in some cases higher than the Provisional Tolerance Weekly Intake (PTWI) recommended by FAO/WHO, which pose a threat to their health. This necessitates the urgent need to undertake a comprehensive study to determine the sources of exposure to these heavy metals. Breast-feeding is of great benefical value for the infant’s development; therefore, efforts should be made to prevent its contamination with environmental pollutants.     

Toxic effects of mercury(II), cadmium(II) and lead(II) porphyrins on Trypanosoma brucei brucei growth

The effects of free mercury(II), cadmium(II) and lead(II) ions and their metalloporphyrin-derivatives on Trypanosoma brucei brucei growth in culture were studied. All experiments were conducted in the dark. IC(50) values on growth obtained in 24-h time-course experiments were 1.5 x 10(-7), 2.4 x 10(-6), 4.4 x 10(-6) and 2.6 x 10(-5) M for mercury(II) porphyrin, cadmium(II) porphyrin, lead(II) porphyrin and free base porphyrin, respectively. While the IC50 values for Hg2+, Cd2+ and Pb2+ were 3.6 x 10(-6), 1.5 x 10(-5) and 1.6 x 10(-5) M, respectively. These results clearly indicate that the toxicity of the metalloporphyrin complexes of mercury(II), cadmium(II) and lead(II) to T. b. brucei parasites was much higher compared to their free metal ions and free base porphyrin at low concentrations. It was also observed after 8 h incubation that the metalloporphyrins were effective in inhibiting the division of the parasites at concentrations >1.25 x 10(-7) M for mercury(II) porphyrin, concentrations >1.2 x 10(-6) M for cadmium(II) and lead(II) porphyrins and at concentrations >3.6 x 10(-6) M for Hg2+ ion. These observations were not detected in samples treated with the free metal ions and the free base porphyrin at the same concentrations. Interestingly, trypanosomes treated with metalloporphyrin complexes displayed different morphological features from those cells treated with free base porphyrin or metal ions. The chemotherapeutic potential of the metalloporphyrins of H2TMPyP for treatment of African trypanosomiasis is discussed.     

Action toxique de quatre métaux lourds (cadmium,cuivre, mercure,plomb) sur la croissance d'Asparagopsis armata Harvey (Rhodophycée: Bonnemaisoniale) en culture

The increase in length of Asparagopsis armata Harvey (Rhodophyceae: Bonnemaisoniale) was measured in various concentrations of lead, mercury, cadmium, and copper. Significant reductions of growth rate compared with controls were observed at 3.70 mg · 1^?1 of lead, 0.31 mg · 1^?1 of cadmium, and 0.092 mg · 1^?1 of copper. The minimal lethal concentration is 0.0296 mg · 1^?1 for mercury, 18.3 mg · 1^?1 for cadmium, and 1.85 mg · 1^?1 of copper.     

Blood Levels of Lead, Cadmium, and Mercury in Residents of Tehran

Monitoring of toxic trace elements for human blood has been of interest to researchers in the fields of environmental chemistry and medical science. The amount of blood toxic elements can reflect the disease state of the person or the environment where that person resides or works. Chronic, low-level exposure to toxic metals such as lead (Pb), cadmium (Cd), and mercury (Hg) is an increasing global problem. This study focuses on obtaining the usual value of Pb, Cd, and Hg in normal human blood. These elements were determined in 61 male and 40 female volunteers resident in Tehran (Iran). The subjects were non-drug abusers and aged 6-62 years old. Procedures were developed for the collection, storage, and preanalytical treatment of samples. The lead and cadmium were determined by graphite furnace atomic absorption spectrometry, and mercury was measured by cold vapor atomic absorption spectrometry technique. The blood levels of Pb, Cd, and Hg in normal volunteers living in Tehran were 123.75 +/- 56.42, 1.82 +/- 0.67, and 8.48 +/- 4.42 microg/L. There was no significant gender-related difference in blood Cd and Hg concentrations (p < 0.06 and p < 0.41). However, the results indicated significantly higher content of Pb in blood of males compared to females (138.11 +/- 65.43 and 101.84 +/- 51.38 microg/L, respectively, p < 0.05).     

四种重金属在金针菇栽培过程中的迁移规律

为了掌握铅、镉、砷、汞4种有害重金属元素在金针菇栽培过程中的富集和迁移,为金针菇产品质量控制提供依据。采用在培养料中添加一定量的铅、镉、汞、砷栽培金针菇,测定其在各栽培阶段培养料、金针菇子实体中的含量。结果表明,在试验的浓度范围内,金针菇子实体中4种重金属的含量随着培养料中添加量的增加而增加,说明金针菇子实体中4种重金属主要是来源于培养料,但金针菇子实体对不同重金属的吸收富集能力不同,对汞的吸收富集能力最强,富集系数最高达到7.590,富集能力大小依次为汞>镉>砷>铅。     

In vitro study on the interactive effects of heavy metals on catalase activity of Sarotherodon mossambicus (Peters)

The in vitro effects of individual heavy metal ions as well as their combinations on catalase activity were investigated. Copper was found to be the strongest inhibitor of catalase activity followed by mercury, iron, chromium and cadmium. Copper toxicity on catalase activity was reduced in the presence of all the other metal ions. However, the addition of cadmium, chromium, iron, manganese, lead to mercury and cadmium, iron, manganese, nickel, lead, zinc to chromium increased their inhibitory effects on catalase activity.     

Survey of metal tolerance in moderately halophilic eubacteria

The tolerance patterns, expressed as MICs, for 250 moderately halophilic eubacteria to 10 heavy metals were surveyed by using an agar dilution method. The moderate halophiles tested included 12 culture collection strains and fresh isolates representative of Deleya halophila (37 strains), Acinetobacter sp. (24 strains), Flavobacterium sp. (28 strains), and 149 moderately halophilic gram-positive cocci included in the genera Marinococcus, Sporosarcina, Micrococcus, and Staphylococcus. On the basis of the MICs, the collection strains showed, overall, similar responses to silver, cobalt, mercury, nickel, lead, and zinc. All were sensitive to silver, mercury, and zinc and tolerant of lead. The response to arsenate, cadmium, chromium, and copper was very heterogeneous. The metal susceptibility levels of the 238 freshly isolated strains were, in general, very heterogeneous among the four taxonomic groups as well as within the strains included in each group. The highest toxicities were found with mercury, silver, and zinc, while arsenate showed the lowest activity. All these strains were tolerant of nickel, lead, and chromium and sensitive to silver and mercury. Acinetobacter sp. strains were the most heavy-metal tolerant, with the majority of them showing tolerance of eight different metal ions. In contrast, Flavobacterium sp. strains were the most metal sensitive. The influence of salinity and yeast extract concentrations of the culture medium on the toxicity of the heavy metals tested for some representative strains was also studied. Lowering the salinity, in general, led to enhanced sensitivity to cadmium and, in some cases, to cobalt and copper. However, increasing the salinity resulted in only a slight decrease in the cadmium, copper, and nickel toxicities.(ABSTRACT TRUNCATED AT 250 WORDS)