Effects Of Lead Contamination Research Articles

Effects of lead contamination on histology, antioxidant and intestinal microbiota responses in freshwater crayfish, Procambarus clarkii

The red swamp crayfish (Procambarus clarkii) is an important farming species in China and there is a high degree of overlap between the main crayfish production areas and areas contaminated with the heavy metal lead (Pb), thus putting crayfish farming at potential risk of Pb contamination. To assess the toxic effects of Pb on crayfish, in this study they were exposed to different concentrations of Pb (0, 0.1, 1, 10, 50 mg/L) for 72 h, and 0.1 mg/L represents the level of Pb in the contaminated water. Histomorphology and activities of antioxidant or immune-related enzymes suggest that the damage of Pb to the hepatopancreas and intestine was dose- and time-dependent, with the intestine being more sensitive to Pb than the hepatopancreas. Notably, after a short period (24 h) of stress at low concentrations (0.1 mg/L) of Pb, the malondialdehyde (MDA) content and antioxidant enzymes such as catalase (CAT) and glutathione peroxidase (GSH-Px) in the intestine of crayfish showed significant changes, indicating that low concentrations of Pb were also highly detrimental to crayfish. High-throughput sequencing of the intestinal microbial community indicated that Pb exposure led to a disturbance in the relative abundance of intestinal bacteria, increasing the abundance of pathogenic bacteria (Bosea, Cloacibacterium, Legionella spp.) and decreasing the abundance of potentially beneficial bacteria (Chitinibacter, Chitinilyticum, Paracoccus, Microbacterium, Demequina, and Acinetobacter spp.). In conclusion, Pb damages the hepatopancreas and intestinal barrier of crayfish, leading to the destruction of their anti-stress ability and immune response, and at the same time disrupts the homeostasis of intestinal microbes, resulting in adverse effects on the gut. This study contributed to the assessment of the ecotoxicity of the heavy metal Pb to the crustacean aquatic animals.

Effect of Lead Contamination on Morphological Attributes and Biomass Allocation of Bambusa balcooa (Roxb.)

Lead contamination in the agricultural soil by anthropogenic activities, industrialization and modernization poses a great concern to human health. A pot experiment was completed to evaluate the effect of Pb concentrations (0, 150, 500, 1000, 1700 mg kg-1) of lead nitrate on Bambusa balcooa plantlets grown in earthen pots placed in a fenced enclosure. For each concentration, three replicates were taken and to reduce the heterogeneity in the results, pots were placed in randomized manner. Thereafter, plantlets were transplanted in the pots and grown in the natural condition, only rainfall was controlled by covering the fenced enclosure with polythene sheet. The result showed that a higher concentration of Pb caused a minimum increase in the number of culm (0%), nodes (25%), leaves (58.53%), length of internode (19.04%), plant height (32.89%) and leaf area (62.91%). Biomass of the plant ranged from 5.33± 0.57 to 37.33±6.42g and moisture content was found maximum in Pb 500 mg kg-1 (38.78%) throughout the experiment. Findings of the study indicates that B. balcooa can tolerate the elevated level of Pb toxicity and can be used for remediation purpose.

Bacterial and fungal diversities examined through high-throughput sequencing in response to lead contamination of tea garden soil.

Several studies have indicated that the heavy-metal content in tea is increasing gradually. Researchers examining the soil of more than 100 tea gardens in China have observed that lead content was higher in some soils. The effect of lead contamination on soil microorganisms in tea gardens was studied to determine the effect of lead on the essential functions of microorganisms in a tea garden soil ecosystem. Previous studies on pot experiments adopted the method of adding a single instance of pollution, which failed to comprehensively simulate the characteristics of the slow accumulation of heavy metals in soil. This study designed with two pollution modes (multistage and single instance) determined the content of soil lead in different forms according to the European Community Bureau of Reference extraction procedure. The community structure, species diversity and functional abundance of soil bacteria and fungi were examined by high-throughput sequencing. We observed that the content of four forms of lead was higher in the multistage contamination mode than in the single instance contamination mode. The effects of lead contamination on bacteria differed significantly (p < 0.05), and the abundance and diversity of bacteria were higher in the multistage contamination mode than in the single instance contamination mode. The community structure of fungi was more affected by lead than was that of bacteria. The content of each lead form was the environmental factor most strongly affecting soil bacteria and fungi. The predicted main function of the bacterial community was amino acid transport and metabolism, and the trophic mode of the fungal community was mainly pathotroph-saprotroph. This study revealed changes in soil microorganisms caused by different forms of lead and contamination methods in tea garden soil and provide a theoretical basis for examining the effects of lead contamination on soil microorganisms.

Nasturtium officinale R.Br. ve Mentha aquatica L. taksonlarının farklı kurşun elementi konsantrasyonlarındaki tepkilerinin araştırılması

In this study, it was aimed to determine the morphological and physiological effects of agricultural activities and lead pollution on Nasturtium officinale and Mentha aquatica macrophytes living in Umurbey Stream (Çanakkale), and also the competition between plants in this region was investigated. Macrophytes were collected between May-June 2016 from the lower part of Gökköy Passage, which is covered with orchards on both sides of Çanakkale province, Umurbey district, Umurbey Stream. The macrophytes were left in the nutrient solution for 3 days for the adaptation process. In the first stage, the effect of lead contamination on the morphology and physiology of macrophyte species was investigated in a single culture at 1, 5 and 10 ppm Pb concentrations. Then, the competitiveness of two macrophyte species at an intermediate dose of 5 ppm Pb in a mixed culture was examined. In addition to the amount of, chlorophyll a and b, carotenoid, free proline, protein, total phenolic compound amount, adsorbed lead amount and total potassium, phosphorus, iron and magnesium amounts were examined. P, Fe, Mg, K, Pb and protein content reached the highest level at the dose of 5 ppm Pb where N. officinale was affected the most morphologically. At the same time, N officinale minimized the photosynthetic pigment and free proline levels at this dose. The dose at which M. aquatica was most affected morphologically was 10 ppm Pb dose. P, Fe, Mg and K contents of M. aquatica at that dose reached the highest value. This study proved that M. aquatica was morphologically and physiologically more resistant in two control groups where there was no lead stress and aquatic plants were grown together. Morphologically and physiologically, it has been shown that N. officinale was more combative when lead was applied as stress. With this study, it was determined that watercress is a good lead accumulator by adsorbing more than twice the lead amount absorbed by water mint.

Hazardous Effects of Lead (Pb) on Hematological and Biochemical Parameters in Awassi Sheep Grazing in the Najaf Center

This study was aimed to compare between lead blood levels and its hazardous effects on hematological and biochemical parameters in Awassi sheep grazed on pastures located in Najaf center and sheep grazed in desert of Al-Najaf province-Iraq. The results showed that the lower blood lead levels in sheep grazed on desert with values enclosed in generally within the normal limits, while, higher blood lead levels were shown in sheep grazed on pasture located in the city center of Al-Najaf, with average values significantly higher than the maximum limits. On the other hand, there are a significant decrease (p<0.05) in hematological parameters (Red blood cells (RBCs), hemoglobin (Hb), packed cell volume (PCV), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC), also, a significant increase (p<0.05) in biochemical parameters (alanine aminotransferase (ALT), aspartate aminotransferase (AST), sorbitol dehydrogenase (SDH), blood urea nitrogen (BUN) and creatinine) but decrease in total protein (TP) in sheep grazed on pasture located in the city center compared with sheep grazing in desert Al-Najaf. Thus, the current study showed that elevated mean blood lead level above the acceptable limit of (0.1 ppm) in all Sheep living in the city Centre, suggesting that iron deficiency anemia may amplify the effect of lead contamination in the environment.

The effect of lead contamination on bioturbation by Lumbriculus variegatus in a freshwater microcosm

The present study investigated the effect of lead (Pb) on bioturbation by the oligochaete worm Lumbriculus variegatus, using freshwater microcosms. The experiment used lead at “0”, 140, 700, and 3500 μg/g in sediment, and used two different laboratory populations of L. variegatus. A molecular genetic analysis and bioassays were conducted to determine if the two populations differed genetically and whether they differed in Pb-sensitivity. The bioturbation of L. variegatus was estimated using luminophores placed at the sediment-water interface at the beginning of the experiment. After the 14 d experiment the luminophore profiles in sediment were used to estimate the biodiffusion and bioadvection coefficients, using the diffusion-advection model. The results showed that the biodiffusion and bioadvection coefficients were generally negatively related to the Pb concentrations in the sediment. Lead at 700 and 3500 μg/g reduced both coefficients, while Pb at 140 μg/g did not. Luminophore profiles in the “0” and 140 μg/g treatments were indicative of a non-local transport, while a diffusive transport was observed at the higher Pb levels. The two laboratory populations of L. variegatus used in the experiment differed in their sensitivity to Pb when mortality was used as the endpoint, but they did not differ in sediment bioturbation or the Pb-sensitivity of this process. Moreover, the genetic analysis did not detect any genetic differences between the populations. This study demonstrated that elevated levels of Pb can impact ecosystem functioning by decreasing the bioturbation activity of benthic organisms such as L. variegatus.

Effects of lead contamination in soils on dry biomass, concentration and amounts of lead accumulated in three tropical pasture grasses

AbstractA greenhouse pot‐experiment was conducted to evaluate the phytoremediation abilities of three tropical pasture grasses (signalgrass, napiergrass and atratum) in response to two types of soils (Kunigami‐maji and Shimajiri‐maji) contaminated with three levels of lead (0, 150 and 300 mg kg–1). The results demonstrated that the dry biomass, lead concentration and the accumulated amounts were different among the plant species and between the soil types. The amounts of dry matter in three tropical pasture grasses grown on Kunigami‐maji soil were higher than that on Shimajiri‐maji soil. On both soils, lead concentration of roots was higher than that of shoots, and it was suggested that transportation of lead from roots to shoots was restricted in these plants. The lead accumulated amounts per plant grown on Kunigami‐maji soil were higher than that on Shimajiri‐maji soil. And, on Kunigami‐maji soil, accumulation of lead was relatively high in both shoots and roots of signalgrass and atratum, while, in napiergrass, the high level of lead was found only in roots. Amounts of lead extracted from the shoots of signalgrass, napiergrass and atratum grown on Kunigami‐maji soil contaminated with the highest lead level of 300 mg kg–1 were 1.64, 0.17 and 0.92 mg plant–1, respectively. As Kunigami‐maji had lower soil pH than Shimajiri‐maji, it can be suggested that lower soil pH may enhance lead bioavailability and uptake by the tropical pasture grasses. In conclusion, signalgrass and atratum could be useful for phytoremediation of lead contaminated soil, especially on Kunigami‐maji soil.

Effects of lead contamination on the clonal propagative ability of Phragmites australis (common reed) grown in wet and dry environments.

Clonal propagation is important for the survival and maintenance of the common reed Phragmites australis. Pot culture experiments were conducted to investigate the effects of lead (Pb) concentration (0, 500, 1500, 3000, 4500 mg·kg(-1) ) and water stress on the clonal reproductive ability of this species. The Pb concentration found in plant organs, in decreasing order, was roots >shoots >rhizomes. There was a negative relationship between the growth of clonal propagative modules (excluding axillary shoot buds) and Pb concentrations, which caused a decrease in biomass, rhizome growth and number of axillary and apical rhizome buds. Daughter axillary shoots exhibited a tolerance strategy, with no significant change in their number; the axillary and apical rhizome buds, daughter apical rhizome shoots and rhizomes exhibited compensatory growth during the late stage of Pb (excluding 4500 mg·kg(-1) ) treatment in a wet environment. Pb applications above 500 mg·kg(-1) reduced these parameters significantly in the drought treatment, except for the number of axillary shoot buds, which did not change. Our results indicate that clonal propagative resistance to Pb contamination can occur via tolerance strategies, compensatory growth and a Pb allocation strategy, enabling these reeds to maintain population stability in wet environments. However, clonal modular growth and reproductive ability were inhibited significantly by the interaction between drought and Pb, which would cause a decline in P. australis populations in a dry environment. Lead concentrations of 4500 and 500 mg·kg(-1) in soils might meet or exceed the Pb tolerance threshold of clonally propagated reeds in wet and dry environments, respectively.

Effects of lead contamination in feed on laying performance, lead retention of organs and eggs, protein metabolism, and hormone levels of laying hens

SUMMARY Five hundred seventy-six Hy-Line Brown hens, 40 wk old, were randomly allotted to 4 groups, each of which included 4 replicates of 36 hens. The groups were given a basal corn-soybean meal diet supplemented with 0 (control group), 15, 30, and 60 mg/kg of lead. No differences were observed for laying rate and FCR among the treatments, whereas adding 15, 30, and 60 mg/kg of lead decreased ADFI. Lead concentrations in albumen, yolk, liver, kidney, oviduct, and ovary of the treatment groups were higher than those of the control group. The addition of lead at 60 mg/kg resulted in increased levels of serum urea nitrogen, urea acid, and glutamic oxalacetic transaminase activity. Levels of serum progesterone, follicle-stimulating hormone, and luteinizing hormone in the control group were significantly higher than those of the treatment groups. In conclusion, we indicate that lead concentrations in tissues and eggs have a positive correlation with dietary lead levels, and lead may affect the reproductive performance of hens by reducing the levels of endocrine hormones.

Effect of Lead Contamination on Soil Microbial Activity Measured by Microcalorimetry

AbstractMicrocalorimetry was used to investigate the microbial activity in three types of soil (orchard soil, crop soil, forest soil) in Wuhan, China, and to evaluate the influence of different concentrations of lead (Pb2+) on soil microbial activity. The experimental results revealed that due to different physical and chemical characteristics of the soils, soil microbial activity in three soil samples were in a descending sequence: orchards soil, crops soil, forest soil. Six levels of Pb viz. 0, 10, 20, 40, 80, 160 μg·g−1 were applied in these soils, and the results showed that an increase of the amount of Pb2+ is associated with a decrease in microbial activity in the soils due to the toxic effect of Pb2+. In order to gain further insight of the sequential change of microorganisms, determination of colony forming units (CFU) was performed to provide a negative linear correlation between the heat effect and the respective number of microorganisms in the system.

Condition for Lead-Induced Corrosion of Alloy 690 in an Alkaline Steam Generator Crevice Solution

Abstract The effects of dissolved lead on the anodic dissolution behavior of Alloy 690 (UNS N06690) were experimentally investigated in an alkaline solution that is used to simulate the environment in a nuclear steam generator crevice. Lead inoculation and scratch techniques were applied to exclude the inference of the impact of oxidization of the metallic lead deposit. It has been found that lead deposit can promote transient dissolution on the bare metal surface in the alkaline crevice solution before a fully passive state is achieved. The experimental measurements suggest that the promoted transient dissolution is likely to result from the selected dissolution of nickel. The presence of dissolved lead contamination may retard the passivation or repassivation of the alloy. The effect of lead contamination is very limited on the uniform anodic dissolution of the alloy at stable passive state in the alkaline crevice solution.

Efeito do chumbo sobre a fertilização artificial e incubação de ovos de jundiá cinza (&lt;em&gt;Rhamdia quelen&lt;/em&gt;)

Aquatic environmental pollution affects the reproductive potential of various species of fish. The present experiment was carried out to evaluate the effect of lead contamination of the water used in artificial fertilization and initial egg incubation of gray jundia ( Rhamdia quelen ). Two assays were carried out distributed in randomly experimental designs, composed by six treatments, with four and six replications, for the first and second assays, respectively. The first assay consisted of the contamination of artificial fertilization water with 0.00; 0.01; 0.02; 0.03; 0.04 and 0.05 mg of Pb L -1 and egg incubation in pure water. The second assay consisted of the contamination of artificial fertilization water and egg incubation water with 0.00; 0.15; 0.30; 0.45; 0.60 and 0.75 mg of Pb L -1 . Only the second assay was affected (p -1 . A linear reduction of the fertilization rate was verified in levels of lead contamination of water above 0.25 mg of Pb L -1 . Lead concentrations levels above 0.25 mg of Pb L -1 cause deleterious effects on the artificial fertilization of gray jundia.

Effects of lead contamination on soil enzymatic activities, microbial biomass, and rice physiological indices in soil–lead–rice ( Oryza sativa L.) system

The effect of lead (Pb) treatment on the soil enzymatic activities, soil microbial biomass, rice physiological indices and rice biomass were studied in a greenhouse pot experiment. Six levels of Pb viz. 0(CK), 100, 300, 500, 700, 900 mg/kg soil were applied in two types of paddy soils. The results showed that Pb treatment had a stimulating effect on soil enzymatic activities and microbial biomass carbon (Cmic) at low concentration and an inhibitory influence at higher concentration. The degree of influence on enzymatic activities and Cmic by Pb was related to the clay and organic matter contents of the soils. When the Pb treatment was raised to the level of 500 mg/kg, ecological risk appeared both to soil microorganisms and plants. The results also revealed a consistent trend of increased chlorophyll contents and rice biomass initially, maximum at a certain Pb treatment, and then decreased gradually with the increase in Pb concentration. Pb was effective in inducing proline accumulation and its toxicity causes oxidative stress in rice plants. Therefore, it was concluded that soil enzymatic activities, Cmic and rice physiological indices, could be sensitive indicators to reflect environmental stress in soil–lead–rice system.

Effects of lead contamination on soil microbial activity and rice physiological indices in soil–Pb–rice ( Oryza sativa L.) system

The effect of lead (Pb) treatment on the soil microbial activities (soil microbial biomass and soil basal respiration) and rice physiological indices were studied by greenhouse pot experiment. Pb was applied as lead acetate at six different levels in two different paddy soils, namely 0 (control), 100, 300, 500, 700, 900 mg kg −1 soil. The results showed that the application of Pb at lower level (<300 mg kg −1) as lead acetate resulted in a slight increase in soil microbial activities compared with the control, and had an inhibitory influence at high concentration (>500 mg Pb kg −1 soil), which might be the critical concentration of Pb causing a significant decline in the soil microbial activities. However, the degree of influence on soil microbial activities by Pb was related to the clay and organic matter contents of the soils. On the other hand, when the level of Pb treatments increased to 500 mg kg −1, there was ecological risk for both soil microbial activities and plants. The results also revealed that there was a consistent trend that the chlorophyll contents increased initially, and then decreased gradually with increase in Pb concentration. Pb was effective in inducing proline accumulation and its toxicity causes oxidative stress in rice plants. In a word, soil microbial activities and rice physiological indices, therefore, may be sensitive indicators reflecting environmental stress in soil–Pb–rice system.

Challenges posed by the precautionary principle and accountability in ecological risk assessment

AbstractIn order to protect the environment, type II errors, e.g. a species is not listed as endangered (H0) when it is in fact endangered (H1), are avoided at the risk of making a type I error. However, it is almost impossible to determine if management efforts have been efficient or if many type II errors have occurred. Applying the precautionary principle to environmental protection without full scientific certainty requires a new academic code for scientists. If we manage ecosystems or bioresources under uncertainty, we need to incorporate new knowledge (accountability) and to change actions with ecosystem states (adaptability). This is called adaptive management. The extinction risk of exploited species under adaptive management is much lower than that under constant exploitation. The revised management procedure (RMP) in whaling and the deer management program in Hokkaido, Japan, share the merit of adaptive management. Under the RMP, the period allowed in considering the extinction risk of the southern hemisphere minke whale is far too long. Population management of over‐abundant deer threatened endangered eagles, because of lead contamination from bullets. Although the effect of lead contamination on the extinction risk of eagles was uncertain, the Hokkaido Government prohibited the use of lead bullets in deer hunting. When designing management programs, it is also important to consider cost–benefit measures in the ecological risks. The value of biodiversity is often much higher than the economic benefit from exploiting the bioresource by agriculture, forestry or fisheries. Copyright © 2003 John Wiley &amp; Sons, Ltd.

Effects of lead contamination on the growth of Lythrum salicaria (purple loosestrife)

The ability of individual species to tolerate or accumulate heavy metal pollutants has been investigated widely. Although invasive species may become established more easily in disturbed environments, relatively little is known about how an ability to tolerate pollutants might give invasive species a competitive advantage. This study is part of a series of experiments investigating native and invasive species interactions with chemical pollution and other forms of disturbance. The purpose of this experiment was to investigate the effects of lead on the growth of Lythrum salicaria. We exposed plants to different concentrations of lead and measured different growth parameters, such as biomass, length, leaf number, and biomass allocation to roots. For most measures, plants grown in lead-free conditions were larger than plants exposed to lead. Plants in the low (500 mg/l) and medium (1000 mg/l) lead treatments did not differ from each other, while plants in the high (2000 mg/l) lead treatment were significantly smaller. However, the biomass allocation to roots was not significantly different among treatments. Although their growth is affected, individuals of Lythrum salicaria demonstrated tolerance to lead contamination, which may aid in their colonization in lead-polluted wetlands.

Respiratory, acid–base and metabolic responses of the freshwater crayfish Cherax destructor to lead contamination

The effects of lead contamination on respiratory, acid–base and metabolic status were investigated in the freshwater Australian crayfish, Cherax destructor. Lead has been found to perturb sodium balance in C. destructor and it seemed likely, given the link between ion regulation and gas exchange in aquatic crustaceans, that respiration and acid–base balance would be compromised. Exposure of C. destructor to either 100 or 0.5 mg l −1 Pb in the water caused a reduction in oxygen consumption ( M ̇ O 2 ) of at least 50% within 24 h, and after 21 days M ̇ O 2 was only 30% of pre-exposure levels. The reduced M ̇ O 2 was accompanied by a decrease in heart rate from 66±9 to 29±6 beats min −1 in the initial 24 h but ventilation rate remained unchanged (23±5 beats min −1). Concomitantly there was a marked reduction of the oxygen transfer factor ( TO 2) across the gills from 2.69×10 −2 μmol Pa −1, typical of crustaceans, to 1.08×10 −2 μmol Pa −1 in impacted crayfish after 21 days exposure. Despite the reduced M ̇ O 2 and TO 2, there was almost no change in the acid–base status of Pb impacted crayfish in comparison to controls. While part of the normal response of C. destructor to hypoxia is a hyperventilation leading to lowered M ̇ O 2 , the apparent hypoxia caused by Pb impact did not elicit any increase in ventilation and thereby no attempt was made to maintain a ‘normoxic’ M ̇ O 2 . Metabolism was not supplemented by anaerobiosis and thus overall energetic demand must have been lowered. This response strongly suggests that Pb promotes a hypometabolic state as well as an elevation of the threshold PO 2 at which anaerobiosis would be initiated. Lead contamination would therefore exclude C. destructor from waters prone to hypoxia.

Determination of Organic Acids in Xylem Sap of Cucumber: Effect of Lead Contamination

Abstract Lead, iron, and organic acid concentrations were determined in low-volume xylem sap samples of cucumbers grown in both “lead-free” and lead-contaminated nutrient solutions containing either Fe-citrate or Fe-EDTA by total reflection X-ray fluorescence spectrometry (iron and lead), graphite furnace atomic absorption spectrometry (lead), and reversed-phase high-performance liquid chromatography (organic acids). Three acids of the Krebs cycle—citric, fumaric, and malic acids—were detected and measured. In presence of Fe-citrate the lead contamination results in about three times higher organic acid production in the cucumber compared with the uncontaminated plants. At the same time the amount of transported iron decreases with about 20%. In presence of Fe-EDTA, the same amount of lead leads to a small change in organic acid production; however, the uptake and the transport processes of iron are considerably hindered (∼35%). Lead transport in the xylem channel was more than one order of magnitude higher when iron was added to the nutrient solution as citrate instead of EDTA complex. These phenomena can be attributed to the participation of the organic acids in the translocation processes of the metals investigated.

A theoretical analysis of the environmental effects of lead contamination over time on IQ, education and crime in America: a viewpoint

Lead poisoning and contamination is a major factor which partly explains why racial minorities in the U.S.A. have lower than average IQ's, social mobility, educational success and economic prosperity. When combined with the factors of low birth weight and childhood neglect/physical abuse, higher minority crime rates are partially explained. The major conclusion is that government war on poverty/economic education and opportunity programs for minorities only occurs after negative, detrimental environmental impacts, such as lead contamination‐poisoning have severely impacted the physical and mental health of minorities as children. If the government authorities are serious about a “War on Poverty”, government programs must be in place to protect and nurture minority children before they are born and through age 6.

The effect of lead on zinc deposit structures obtained from high purity synthetic and industrial acid sulphate electrolytes

Zinc deposits contaminated with lead were found to have characteristic morphologies and orientations which were dependent on the amount of lead present in the zinc deposits and to a lesser extent on the presence of other impurities such as antimony and glue in the deposits. Increasing lead in the zinc deposits progressively changed the orientations from (1 1 2) to (1 0 1) to (1 0 0) to finally a poorly crystalline (0 0 2) structure. The lead content of the zinc deposits was dependent on both the concentration and chemical composition of lead added to the electrolyte, the current density and also on the presence of antimony or glue in the electrolyte. A relationship was shown to exist between the effect of lead contamination on zinc deposit morphology and orientation and on the overpotentials associated with zinc electrodeposition in the presence of lead.