Increase In Lead Concentration Research Articles

Low sedimentary accumulation of lead caused by weak downward export of organic matter in Hudson Bay, northern Canada

Atmospheric input of anthropogenic lead increased globally over the last centuries. The present study shows that the concentrations of lead in sediment cores from low-productivity Hudson Bay, northern Canada, remained relatively constant over the last centuries. The lack of imprint of the increased anthropogenic lead input in this marine environment is not consistent with the increased lead concentrations in nearby lakes over the same period. In addition, the observed trend in lead isotopic composition in our cores suggests an apparent progressive overprint of anthropogenic lead during the 1900s. In other words, isotopes clearly registered the increasingly anthropogenic nature of lead in the sedimentary record, but total lead concentrations remained constant, indicating that some process limited the export of lead to the sediment. These observations point to a long-term limitation of the downward export of particles in Hudson Bay. Given that the source of lead was the same for both Hudson Bay and neighboring high-productivity lakes, we hypothesize that the very low primary productivity of Hudson Bay waters was responsible for the low vertical export of lead to marine sediments. We further propose that primary productivity is the most important factor that generally drives the vertical export of particulate matter, and thus hydrophobic contaminants, in near-oligotrophic marine environments.

Effect of thiamine and vitamin C on tissue lead accumulation following experimental lead poisoning in Cyprinus carpio

The present study was conducted to evaluate the possible ameliorative effects of vitamin C and thiamine on lead accumulation in kidney, liver, muscle, brain and gill of experimentally lead-poisoned common carp. At the beginning of the experiment, fish (n=120) were divided into 4 groups randomly with group 1 being considered as the control group. Groups 2, 3 and 4 were exposed to lead acetate (5 mg/L, 15 days); groups 3 and 4 received vitamin C (500 mg/kg feed) and thiamine (50 mg/kg feed) during lead acetate exposure, respectively. Following this, it was observed that lead exposure caused a significant (p < 0.05) increase in lead content in all examined tissues of fish in group 2 in comparison to control group. It was also found that thiamine supplementation slight ly decreased the augmented levels of lead in the muscle, brain and gill tissues, which was not significantly different from that of the control group. Similarly, vitamin C supplementation reduced the augmented concentrations of lead in the muscle to the levels that were not significantly different from that of the control group. Based on the present results, neither thiamine nor vitamin C was effective in providing a significant reduction of tissue lead burden in groups 3 and 4 as compared to group 2. Thus, monotherapy with such vitamins cannot be proposed as a suitable therapeutic approach for the effective reduction of the tissue lead burden in common carp. However, further investigations using other dosing regimens of each vitamin or combined treatment with chelators are required to reach such a conclusion.

429 Effect of increasing lead concentrations in diets on the lead residue of the liver and feather in broiler chickens

An experiment was conducted to investigate the effect of increasing lead concentrations in diets on the lead residue of the liver and feather in broiler chickens. A total of 800 2-d-old Ross 308 broiler chicks were used and allotted to 1 of 5 dietary treatments with 16 replicates consisting of 10 birds in a completely randomized design. Dietary lead concentrations were set to 0, 50, 100, 200, or 400 mg/kg by adding lead acetate (≥ 54.6%) at the expense of the celite. The experimental diets were fed to birds for 5 weeks. At the conclusion of the experiment, 1 bird from each replicate was euthanized. Liver and feather samples were collected for the lead residue analysis. Results indicated that increasing lead concentrations in diets increased the lead residue of the liver (linear and quadratic, P < 0.05) and feather (linear, P < 0.01) in broiler chickens. Broiler chickens fed diets containing 400 mg/kg lead had greater (P < 0.05) lead residue in the liver than those fed the control diets. However, broiler chickens fed diets containing 200 mg/kg lead had greater (P < 0.05) lead residue in the feather than those fed the control diets. In conclusion, increasing lead concentrations in diets up to the level of 400 mg/kg increased the lead residue in the liver and feather tissues; however, only feather shows a dose-dependent linear response. A greater than 400 mg/kg lead in diets significantly increases the lead residue of the liver and feather in broiler chickens.

Development of alginate gel beads with a potential use in the treatment against acute lead poisoning

The objective was to develop alginate beads that could adsorb lead ions in gastric pH, in view to preconize their use in gastric lavage following lead poisoning. The swelling measurements of both, dry and hydrated beads, were carried out in simulated gastric fluid (SGF). The sorption kinetics was examined at lead concentrations ranging from 50 to 200mg/l. Calcium released during the sorption process was investigated.The swelling rate of the dry beads increased considerably with time increase and reached the equilibrium at 736% after 240min; concerning the hydrated beads, the equilibrium swelling reached 139% after 180min. The adsorption of Pb (II) in SGF by dry beads increased with the increase of time and initial lead concentration. The adsorption kinetics of Pb ions by hydrated alginate beads indicated a rapid binding of Pb ions to the sorbent during the first 15min for all the concentrations, followed by a slow increase until the equilibrium was reached after 90min. The adsorption capacity of Pb ions increased with the increase of the storage time in water at 4°C and with the weight. The amount of Ca2+ released by the beads increased with the increase of Pb ions a rate.

The effect of lead and some operating parameters on cathode contamination during zinc electrowinning

The influence of various operating parameters such as lead concentrations as impurity, current density, acid concentration and temperature was investigated in acid zinc sulfate electrolyte. Nucleation overpotential (NOP) for various experimental conditions was determined using cyclic voltammetry technique. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Inductively coupled plasma (ICP) were employed to study the physical and chemical characteristics of zinc deposits. By adding lead to the electrolyte, the current efficiency (CE) was changed from 94.04% for the electrolyte without lead to 95.37% for the solution containing 0.2mgL−1 Pb (1.33% increase). However, in the presence of higher lead concentrations (0.2–0.8mgL−1), a gradual improvement of CE (0.94%) was found. The results revealed an increase of NOP up to 25mV with the increase of lead concentration up to 0.8mgL−1 in the electrolyte while the rise of acid concentration and temperature lowered the NOP for zinc deposition for 14 and 9mV, respectively. The increase of current density from 45 to 60mA improved CE from 94.59% to 95.41% while that of temperature from 35 to 45°C, enhanced the CE from 94.63% to 95.64%. However, the increase of acidity (158 to 170g) lowered the CE from 96.58% to 95.60%. The stirring rate up to 412rpm did not significantly influence the nucleation overpotential values. However, increasing the scanning rate resulted in an increase of NOP values, indicating nucleation improvement and crystal rearrangement.

Complex Permittivity to Detect Lead in Soil with Various Salt Forms and Combinations

The response of soil-water systems to an external electric field can be described as polarization and conduction. Polarization represents the electric charges stored in a material, whereas conduction is the ability of a material to conduct free charges. The combined effects of polarization and conduction can be expressed in terms of complex permittivity. Since the complex permittivity of a soil-water system is a function of soil properties, this research was undertaken to detect soil contamination using the complex permittivity measurements. The system used in this investigation to measure the complex permittivity of a lead contaminated soil consisted of an Automatic Network Analyzer (ANA), a set of coaxial cables, a personal computer (PC) for data processing and a coaxial sample holder. Two sample holders were first used: long holder and short holder. It was found that the short holder can give reliable and close measurement to the long holder. The short holder was later adopted. Soil samples were prepared in the lab and mixed with lead nitrate solutions and with hybrid blend of lead nitrate and lead chloride solutions. The relationship between the complex permittivity and lead concentration was investigated. A chemical analysis of the pore fluids for all lead contaminated soil samples was conducted to trace the presence of lead in soil. It was found that the complex permittivity is affected by lead concentration in soil, as the real part decreased and the imaginary part increased with an increase in lead concentration. Lead was not detected in the soil pore water for the soil tested, which suggested that lead was immobilized by precipitation and the adsorption mechanism.

Lead, isotopes and ice: a deadly legacy revealed

Abstract The earliest known use of lead was in the Neolithic period; by Roman times it was in widespread use, despite recognition that it could have adverse effects on human health. The early smelting processes were inefficient, giving rise to atmospheric pollution; as this reduced with modern improvements in furnace design, so pollution due to the addition of tetraethyl lead to motor fuel emerged. The military use of lead was a further source of environmental contamination, while individuals were exposed to lead from water pipes, paint and solder in food cans. Studies of lead in ice cores recovered from Greenland demonstrated a 200-fold increase in lead concentration from 800 BCE to the 1960s, with the greatest increase occurring after 1940. The isotope signatures of lead enabled the sources of environmental contamination to be determined: industrial lead was responsible throughout most of the last millennium, with lead in fuel making the greatest contribution in recent times. The human impact was demonstrated in studies of archaeological and modern skeletal lead levels. This paper explores the history of the use of lead and the development of an understanding of its toxicity, and examines its impact on human health.

Effect of occupational lead exposure on the blood pressure of lead-exposed workers

Objective: To investigate the effect of occupational lead exposure on blood pressure and pro-vide supportive evidence of health protection on lead - exposed workers. Methods: 612 workers (452 lead - ex-posed workers, 160 workers as control) were recruited in the battery factory. The blood lead concentration and blood pressure were detected by occupational health examination and biological monitoring. The relationship of blood lead concentration and blood pressure wasanalyzed. Results: The blood lead concentration in the exposed group (249.84±137.74) μg/L was higher than that of the control group (117.25±70.15) μg/L, and the differ-ence was statistically significant (P<0.01) . The difference of abnormal blood pressure and diastolic pressure among the exposed and the control group was statistically significant (P<0.05) . The abnormal blood pressure rate, systolic pressure rate and diastolic pressure rate in the 400~726 μg/L group was higher than that of the 6~199 μg/L and 200~399 μg/L group, and the difference was statistically significant (P<0.01) . Multiple lin-ear regression analysis showed that the influencing factors of the systolic pressure followed by sex, age, length of service and blood lead concentration, diastolic pressure followed by sex, age, smoke and blood lead concen-tration. Conclusion: These findings suggest that long - term occupational lead exposure may result in the in-crease of blood lead concentration.

Growth, Survival, Protein Content, and Phytoremediation Potency of Various Rangeland Plant Species (Medicago polymorpha L., Medicago rigidula L., and Onobrychis sativa L.) Grown in Vermicompost-Containing Potting Media

ABSTRACTA pot experiment based on completely randomized factorial arrangement design with four replications was conducted under greenhouse condition at Malayer University, Malayer, Iran. Pots contained a mixture of soil and different concentrations (0% and 60% w/w) of vermicompost. Plants were exposed to three lead nitrate concentrations: 0, 4, and 8 mM. Based on the results of this research, shoot height and root length of the studied plants significantly decreased with increased lead concentrations in all vermicompost application levels. Generally, plants exposed to lower levels of lead and vermicompost application had higher root:shoot ratio. The survival capacity of all the studied plants was significantly reduced with increased lead concentrations, but increased with increased vermicompost application level. The total protein content increased with decrease in lead nitrate concentration, but decreased with decrease in vermicompost application. Generally, translocation factor increased significantly as vermicompost application rate increased. The highest root concentration factor of lead was found in V1×Pb2 as compared to the other treatment levels. Generally, tolerance index values of all the studied plants were significantly higher in the lower lead concentration treatments.

USING OF THE ISOLATED FUNGI FROM PROBABLE CONTAMINATED REGIONS IN THE BIOLOGICAL TREATMENT OF LEAD AND CHROMIUM CONTAMINATION IN RAMADI CITY

The study included isolate and diagnose some fungi from possible contamination sites in Al-Ramadi city. And inoculated the liquid culture media contaminated with differing concentrations of lead and chromium by this fungus and two periods 7 and 14 days. results showed the fungus Fusarium sp. records the highest rate of removal of lead and chromium, and the duration of has no effect mentioned on the rate of removal of the lead and chromium, as the relationship between increase in lead and chromium concentration in the liquid media and the ability of fungi on removal was inverse.

Glazed clay pottery and lead exposure in Mexico: Current experimental evidence

Objectives: Lead exposure remains a significant environmental problem; lead is neurotoxic, especially in developing humans. In Mexico, lead in human blood is still a concern. Historically, much of the lead exposure is attributed to the use of handcrafted clay pottery for cooking, storing and serving food. However, experimental cause-and-effect demonstration is lacking. The present study explores this issue with a prospective experimental approach.Methods: We used handcrafted clay containers to prepare and store lemonade, which was supplied as drinking water to pregnant rats throughout the gestational period.Results and discussion: We found that clay pots, jars, and mugs leached on average 200 µg/l lead, and exposure to the lemonade resulted in 2.5 µg/dl of lead in the pregnant rats’ blood. Neonates also showed increased lead content in the hippocampus and cerebellum. Caspase-3 activity was found to be statistically increased in the hippocampus in prenatally exposed neonates, suggesting increased apoptosis in that brain region. Glazed ceramics are still an important source of lead exposure in Mexico, and our results confirm that pregnancy is a vulnerable period for brain development.

Behaviour mechanisms and correlation between lead (Pb) and its isotope 210Pb in industrial residue as an indicator for waste characterization

ABSTRACTTotal lead and 210Pb concentrations were determined in various ash fractions (collected from two of the world’s largest oil shale-fired power plants) by inductively coupled plasma mass-spectrometry (ICP-MS) and gamma spectrometry. Results show a clear increase in total lead (values up to 193 ppm in filter ashes) and 210Pb (values up to 148 Bq kg−1 in filter ashes) concentrations in the ash fractions from the furnace towards the filter ashes. A strong positive linear correlation (Pearson’s bivariate correlation remained between 0.86 and 0.99) was determined between total lead concentration (ppm) and 210Pb activity concentration (Bq kg−1) within all the boilers under observation. The constant concentration ratio between total lead and 210Pb remained around one (with minor exceptions), independent of the sampling location and the used combustion technology. The determined concentration ratio can be applicable as an indicative tool in waste material characterization. It also provides multiple additions to the general material characterization approach, by integrating radiological and elemental studies and providing an option to rapidly obtain initial indicative information about the residues. This in turn helps to generate the initial information to work out the next steps in waste material management.

Positive anomalous concentrations of Pb in some gabbroic rocks of Afikpo basin southeastern Nigeria.

Gabbroic rocks have intruded the sedimentary sequence at Ameta in Afikpo basin southeastern Nigeria. Petrographic and geochemical features of the rocks were studied in order to evaluate their genetic and geotectonic history. The petrographic results show that the rocks contain plagioclase, olivine, pyroxene, biotite, iron oxide, and traces of quartz in three samples. Major element characteristics show that the rocks are subalkaline. In addition, the rocks have geochemical characteristics similar to basaltic andesites. The trace elements results show inconsistent concentrations of high field strength elements (Zr, Nb, Th, Ta), moderate enrichment of large-ion lithophile elements (Rb, Sr, Ba) and low concentrations of Ni and Cr. Rare earth element results show that the rocks are characterized by enrichment of light rare earth elements, middle rare earth elements enrichment, and depletion of heavy rare earth elements with slight positive europium anomalies. Zinc concentrations are within the normal range in basaltic rocks. There are extremely high concentrations of Pb in three of the rock samples. The high Pb concentrations in some of these rocks could be as a result of last episodes of magmatic crystallization. The rocks intruded the Asu River Group; organic components in the sedimentary sequence probably contain Pb which has been assimilated into the magma at the evolutionary stage of the magma. Weathering of some rocks that contain galena could lead to an increase in the concentration of lead in the gabbroic rocks, especially when the migration and crystallization of magma take place in an aqueous environment. Nevertheless, high concentration of lead is hazardous to health and environment.

Rapid evolutionary loss of metal resistance revealed by hatching decades-old eggs.

We investigated the evolutionary response of an ecologically important freshwater crustacean, Daphnia, to a rapidly changing toxin environment. From the 1920s until the 1960s, the use of leaded gasoline caused the aquatic concentration of Pb to increase at least fivefold, presumably exerting rapid selective pressure on organisms for resistance. We predicted that Daphnia from this time of intense pollution would display greater resistance than those hatched from times of lower pollution. This question was addressed directly using the resurrection ecology approach, whereby dormant propagules from focal time periods were hatched and compared. We hatched several Daphnia genotypes from each of two Swiss lakes, during times of higher (1960s /1980s) and lower (2000s) lead stress, and compared their life histories under different laboratory levels of this stressor. Modern Daphnia had significantly reduced fitness, measured as the population growth rate (λ), when exposed to lead, whereas those genotypes hatched from times of high lead pollution did not display this reduction. These phenotypic differences contrast with only slight differences measured at neutral loci. We infer that Daphnia in these lakes were able to rapidly adapt to increasing lead concentrations, and just as rapidly lost this adaptation when the stressor was removed.

Lead, cadmium, and arsenic in commercial algae of the Sea of Japan

The concentrations of toxic elements (arsenic, cadmium, lead) in commercial algae Saccharina japonica and Ahnfeltia tobuchiensis from different habitats of the Sea of Japan have been determined. Bioaccumulation of heavy metals has been analyzed with respect to the habitat and growth conditions. The lead content of Sascharina japonica from all habitats and arsenic content of the same alga species from the Ol’ga Bay, Kievka Bay, and Tatar Strait have been found to exceed maximum permissible levels. Increased lead concentrations have been detected in Ahnfeltia tobuchiensis. Samples of Ahnfeltia tobuchiensis collected from the bottom layer contain more toxic elements than those from the upper layer.

Was Moshyttan the earliest iron blast furnace in Sweden? The sediment record as an archeological toolbox

Recently, archeological study of the establishment and spread of iron blast furnace technology in Sweden has suggested a phase of rapid expansion from AD 1150 to 1350, mainly in the historically important “Bergslagen” region in central Sweden. But the geographical extent and earliest development remains debated. One archeological investigation of Moshyttan, in the less studied western part of Bergslagen, suggested that it may have been established before 1150. To independently study the timing of blast furnace establishment at Moshyttan, and also the vegetation history of the area, we performed a multiproxy analysis of the sediment record from Fickeln, a small lake immediately downstream of the smelter site. We present radiocarbon dating (macrofossils and bulk sediment), pollen, charcoal particles and geochemistry. To establish a reliable age-depth model, ages of the bulk samples were corrected for old carbon and the model was validated by comparison to chronological markers (immigration of Picea abies and airborne lead-pollution) in other lakes with varved or otherwise robust chronologies. Based on markedly increasing lead concentrations, decreases in the 206Pb/207Pb ratio towards values resembling Bergslagen ores, increasing charcoal particle counts and increases in iron and zinc concentrations, the establishment of the blast furnace is estimated to AD 1250–1300 with an age-depth model probability of 91%. This places the establishment of the blast furnace at Moshyttan within the known period of early expansion of iron blast furnaces in Sweden, rather than earlier as suggested by the earliest dates from the archeological study. The first signs of a human presence in the area can be seen in pollen associated with forest grazing from ca. 170BC, and the first signs of cultivation appear ca. AD 1020, preceding the blast furnace by 200years.

Effect of Pyrolysis Temperature on Cadmium and Lead Concentration Distribution of Some Selected Tobacco Cigarettes in Nigeria

Consumption of tobacco as cigarette or otherwise has been demonstrated to contribute to air pollution via smoke generation resulting in adverse health effect. Therefore, this study investigates the effect of pyrolysis temperature on the concentration, distribution of cadmium and lead between ash residue and smoke in some selected cigarettes in Nigeria. Four samples consisting of three different brands of cigarette, Benson, Excel, London and fresh tobacco leaves were considered. Each of the samples was pyrolyzed at different temperatures of 300, 400 and 500°C and ash residues were collected and digested for determination of cadmium and lead concentrations using atomic adsorption spectrometer consequent upon which concentration in the smoke were calculated. For all the samples considered, it was observed that increasing the pyrolysis temperature from 300 to 500°C resulted in a decrease in concentration of cadmium and lead in ash residue and an increase in concentration of cadmium and lead in the smoke. Key words : Tobacco, cigarette, ash residue, smoke, combustion.

Lead-resistant strain KQBT-3 inoculants of Tricholoma lobayensis Heim that enhance remediation of lead-contaminated soil

To enhance lead-detoxifying efficiency of Tricholoma lobayensis Heim, one lead-resistant strain KQBT-3 (Bacillus thuringiensis) was applied owing to its excellent ability to tolerate Pb. KQBT-3 domesticated in liquid medium with increasing lead concentrations could tolerate Pb(NO3)2 up to a concentration of 800 mg L−1. Pot experiments showed that the KQBT-3 not only could promote the growth of T. lobayensis, but also could enhance its Pb accumulation ability under heavy metal stress. Biomass and accumulation of Pb increased 47.3% and 33.2%, respectively. In addition, after inoculation of KQBT-3, the significant decrease of malondialdehyde indicated KQBT-3 could alleviate lipid peroxidation in T. lobayensis. What is interesting is that superoxide dismutase and peroxidase activities in T. lobayensis inoculated with KQBT-3 were increased, and the maximum increasing rate was 121.71% and 117.29%, respectively. However, the catalase activity increased slightly. This revealed that inoculating KQBT-3 further induced oxidative response in T. lobayensis due to Pb accumulation. Therefore, the present work showed that KQBT-3 made a major contribution to promote growth and lead uptake of T. lobayensis and alleviate the oxidative stress. This kind of auxiliary effect on macrofungi can be developed into a novel bioremediation strategy.

Effect of pressure on the parameters of the superconducting transition in In-doped PbzSn1−zTe semiconducting solid solutions

The effect of hydrostatic pressures up to 10 kbar and lead content on the superconducting and electrical characteristics of indium-doped (5 at. %) PbzSn1−zTe semiconducting solid solutions is studied. Experimental correlations are found for these pressure dependences. When the pressure is raised to P = 6.8 kbar in this material with a lead content z = 0.45 the superconductivity threshold increases to Tc = 1.7 K, which is typical of the compound with z = 0.05 at atmospheric pressure. Increasing the hydrostatic pressure P &amp;gt; 3 kbar in (Pb0.05Sn0.95)0.95In0.05Te causes Tc to fall below 1 K. These features, along with the bell-shaped Tc(P) curve for z = 0.3, are explained by a shift in the energy EIn of the quasilocal states and the Fermi level which is stabilized by them, from the L-band into the Σ-valence band with a high density of states (most noticeable for z = 0.45). A concentration threshold for emergence of the Fermi level from the Σ-valence band with increasing lead content was found using Hall effect measurements at T = 77 K.

Strength and elongation of spray formed Al-Si-Pb alloys

The strength and elongation to fracture of spray deposited Al-Si-Pb alloys were studied as a function of lead content, silicon content, and distance from the centre to periphery of the deposit. It is found that the ultimate tensile strength, proof stress and elongation to fracture decrease, linearly and exponentially, with the increase in lead content and porosity of the deposit, respectively. Both the strengths and elongation to fracture linearly increase with increasing distance from the centre to periphery of the deposit. The ultimate tensile strength and proof stress are higher at a higher silicon content and they have a linear relationship with the hardness of the deposit.