Cadmium level in blood and milk from animals reared around different polluting sources in India

Cadmium in Selected Organs of Game Animals from Areas with Different Degrees of Industrialisation and Its Intake by Human Consumers

The aim of this study was to determine the concentration of cadmium (Cd) in the organs of game animals from areas with different degrees of industrialisation and to assess its intake following the consumption of the livers of these animals. The material for this study consisted of liver and kidney samples taken from roe deer (Capreolus capreolus), red deer (Cervus elaphus), and wild boar (Sus scrofa) from five regions differing in land use and industrialisation. Compared to the kidneys, the liver was an indicator of the current state of the environment and Cd intake, while the kidney was used to assess the long-term accumulation of Cd in the body. The cadmium concentration in the samples was determined by inductively coupled plasma atomic emission spectrometry. The cadmium concentrations of the organs were found to vary according to geographical location, with the highest levels being observed in Southern Poland, i.e., areas characterised by the highest degree of industrialisation and the presence of heavy industry. However, high Cd concentrations were also reported in the northeastern region. Examples of excessive cadmium levels in the kidneys were noted in all tested regions. Cd intake by humans was evaluated by calculating the estimated daily cadmium intake, and this was compared with the tolerable weekly intake (TWI). The TWI was only exceeded by children frequently consuming wild boar liver from the southwest region.

Cadmium as an ovarian toxicant: A review

Cadmium (Cd) is a ubiquitous heavy metal toxicant with no biological function in the human body. Considerably, because of its long biological half-life and very low excretion rate, Cd is inclined to accumulate and cause deleterious effects on various body organs (e.g., liver, kidney, and ovary) in humans and animals. Ovaries are the most vulnerable targets of Cd toxicity. Cd has been shown to induce oxidative stress, follicular atresia, hormonal imbalance, and impairment of oocyte growth and development. Moreover, Cd toxicity has been associated with increasing incidences of menstrual disorders, pregnancy loss, preterm births, delayed puberty, and female infertility. Therefore, it is crucial to understand how Cd poisoning impacts specific ovarian processes for the development of preventive interventions to enhance female fertility. The current review attempts to collate the recent findings on Cd-induced oxidative stress, follicular apoptosis, steroid synthesis inhibition, and teratogenic toxicity, along with their possible mechanisms in the ovarian tissue of different animal species. Additionally, the review also summarizes the studies related to the use of many antioxidants, medicinal herbs, and other compounds as remedial approaches for managing Cd-induced ovarian toxicity.

Effects of Heavy Metal Exposure from Leather Processing Plants on Serum Oxidative Stress and the Milk Fatty Acid Composition of Dairy Cows: A Preliminary Study

This study investigated whether unsaturated fatty acids in milk and the oxidative status of cows are affected by heavy metal exposure due to leather processing. The blood lead (Pb) concentrations in cows from two farms in the polluted area were 16.27 ± 8.63 μg/L, respectively, which were significantly (p < 0.05) higher than the blood Pb concentrations in cows from an unpolluted farm (6.25 ± 3.04 μg/L). There were significantly (p < 0.05) lower levels of glutathione S-transferase (GST), glutathione peroxidase (GPX), and glutathione (GSH) in the serum of cows from the polluted area compared to the levels in cows from an unpolluted area. The linoleic acid (C18:2n6c) content in milk from the polluted area was 15% lower than in the control area. There was a significant correlation between linoleic acid in milk with the blood Pb and serum GSH levels. Heavy metals can alter fatty acid synthesis through oxidative stress, which may be the mechanism by which heavy metals affect fatty acid synthesis in milk.

The Occurrence, Pathways, and Risk Assessment of Heavy Metals in Raw Milk from Industrial Areas in China

This study evaluated chromium (Cr), arsenic (As), cadmium (Cd), and lead (Pb) contamination in raw milk from industrial areas in China, identified the possible pathways of heavy metals from the environment to raw milk, and made a risk assessment of the consumption of heavy metals from milk consumption. The Cr, As, Cd, and Pb concentrations in raw milk, water and silage were analyzed using inductively coupled plasma mass spectrometry. The Cr and As in soil were analyzed by flame atomic absorption spectrometry and atomic fluorescence spectrometry, respectively. Cd and Pb in soil were determined by a Graphite furnace atomic absorption spectrophotometer. The Cr and As concentrations in milk from industrial areas were 2.41 ± 2.12 and 0.44 ± 0.31 μg/kg, respectively, which were significantly higher (p < 0.01) than those from non-industrial areas, which had levels of 1.10 ± 0.15 and 0.25 ± 0.09 μg/kg, respectively. Chromium was mainly transferred through the soil-silage-milk pathway, As was transferred through the water-silage-milk pathway, while Cd was mainly transferred through the soil (water)-silage-milk pathway. The contributions of each metal to the overall hazard index (HI) followed a descending order of As, Cr, Pb, and Cd, with values of 46.64%, 25.54%, 24.30%, and 3.52%, respectively. Children were at higher risk than adults.

Heavy metals in blood, milk and cow's urine reared in irrigated areas with wastewater

The aim of this work was to determine the content of lead (Pb), chromium (Cr), cadmium (Cd), arsenic (As), copper (Cu), strontium (Sr) and thallio (Tl) in blood, milk and urine from cows fed forage irrigated with sewage water and cultivated in the vicinity of the Popocatépetl volcano and determine the rate of transfer of these elements from blood to milk and urine. Digestion was performed in a microwave oven (CEM-MarsX). The determination was made using an ICP -OES. The Cd in the blood was significantly higher than in milk and urine. The Cr in the blood was higher than in the urine. In milk the content of Pb and Cu was significantly higher than in blood. Sr and Tl concentration in the urine was higher than that detected in milk and blood and Pb in blood. Milk transfer Index revealed a significant difference in relation to the TI values found in the urine and only in the case of Cu in milk was TI > 1. In urine, the values found of Sr and Tl were higher than milk TI. It is concluded that when metals are ingested by cows in fodder, they are easily transferred to milk and urine through the blood. Presence of heavy metals in the different matrices determines the degree of environmental and trofic chain contamination with which we can consider the cow a biomarker.

Risk assessment of heavy metals in milk from cows reared around industrial areas in India

This study assessed the health risk associated with exposure to heavy metals through consumption of milk from cows reared around industrial areas in India. Heavy metals, namely Cu, Zn, Cr, Pb, and Cd, were determined in water and forage from four locations as well as in milk produced by dairy cattle raised in these locations, using inductively coupled plasma-mass spectrometry. A quantitative risk assessment using probabilistic approaches was performed to assess the exposure of adults and children to the heavy metals via milk consumption. In milk samples, the highest levels of Cd and Pb were 0.18 mg L^-1 and 0.37 mg L^-1, respectively, which were above the international permissible levels. Possible sources of Pb in the milk could be the industrial by-products and wastes or automobiles exhaust gas. Significant (P < 0.05) positive relationships were found between the concentration of Cu, Cr, Pb, and Cd in milk and in the environmental samples (water or forage). Exposure assessment showed that milk consumers were mostly exposed to Zn, Cd, and Pb, with 63.7%, 51.2%, and 41.2% of children exposed to a dose greater than the references dose for these metals, respectively. Our results suggest that industrial activities lead to possible transfer of heavy metals to cows from their rearing environment (water, plant), which can be accumulated and cause potential health risks to milk consumers. The outcome of this study can be used by policy makers to manage the potential health risk.

MAPK/iNOS pathway is involved in swine kidney necrosis caused by cadmium exposure

Cadmium (Cd) pollution in the environment could cause toxic damage to animals and humans. MAPK pathways could regulate their downstream inflammatory factors, and plays a crucial role in necrosis. Since the swine kidney tissue is an important accumulation site of Cd and target organ of its toxic damage, but the damage form of Cd to swine kidney and the role of MAPK pathways in it are still not clear, we selected six week old weaned piglets as the research object, and fed a diet supplemented CdCl₂ (20 mg/kg) to establish the model of liver injury induced by Cd. The expressions and phosphorylation of MAPK pathways (ERK, JNK, p38), expression levels of inflammatory factors (TNF-α, NF-κB, iNOS, COX-2 and PTGE) and necrosis related genes (MLKL, RIPK1, RIPK3 and FADD) and heat shock proteins (HSPs) were detected by RT-PCR and Western blot. H.E. staining was used to determine the damage of kidney caused by Cd exposure. The results showed that Cd exposure could activate p38 and JNK pathway phosphorylation, rather than ERK 1/2, up regulated the expressions of inflammatory factors, finally induced programmed necrosis (increasing the expressions of MLKL, RIPK1, RIPK3 and FADD) in swine kidney. Our study elucidated the mechanism of Cd-damage to swine kidney and the relationship among MAPK pathways, inflammatory factors and programmed necrosis in swine.

Detrimental effects of long-term exposure to heavy metals on histology, size and trace elements of testes and sperm parameters in Kermani Sheep

Exposure to endocrine-disrupting chemicals (EDCs) has been hypothesized as a cause of declining sheep reproductive efficiency. Understanding the long-term effects of EDCs such as heavy metals on reproductive health requires investigation in 'real life' of sheep that are reared in industrial areas. The aim of this study was to evaluate the effect of long-term exposure of Kermani rams to high levels of environmental heavy metals probably emitted from a copper smelter at KhatoonAbad in ShahreBabak, Kerman province. Testicular characteristics were determined in randomly-selected rams (3-4 years old) at 4 directions (south, north, east, and west) and 4 distances (10, 20, 30, and 40 km) from the smelter. Testicular trace element contents, size, serum testosterone, histological attributes and seminal characteristics, except semen volume, were affected by both the direction and the distance from the smelter (P < 0.05). Testicular contents of Pb, Cd, Cr, and Ni, and sperm abnormalities were higher at 10 km south from the smelter and lower at 40 km west. Other parameters were higher at 40 km west and lower at 10 km south. Interestingly, the testicular contents of Cu at 10 km south were lower and associated with higher sperm abnormalities in the rams reared closer to the smelter. The highest weight, length and circumference of the testis were found at 40 km west. The lowest concentration of testosterone was observed at 10 km south, being 92.6% lower than the highest values obtained at 40 km west. The diameter of seminiferous tubules and epithelial height at 10 km south were 8.9% and 27.5% lower than the highest values obtained at 40 km west. A positive correlation between Pb, Cd, Cr and Ni contents in the testis with sperm abnormalities, and a negative correlation between these elements with the other parameters were found. It was concluded that long-term exposure to heavy metals might have been a cause of decreased fertility in rams and probably other living species in this region.

Concentrations of toxic metals and essential elements in raw cow milk from areas with potentially undisturbed and highly disturbed environment in Slovakia

Dietary composition and husbandry practices largely determine the essential trace element status and the toxic metal exposure of livestock and consequently their concentrations in animal products. The main objective of this study was to determine the real contamination of selected areas of Slovakia compared with existing Environmental regionalization of the Slovak Republic (SR) created by the Ministry of the Environment SR. Another aim of this study was to determine the content of essential and toxic metals in feed and milk of dairy cows on selected farms in Slovakia referred to the suitability of the use of milk from these areas to other food processing. This article deals with the analysis of the content of selected elements in feed and milk of dairy cows in the area of Novoť (Northern Slovakia; area with undisturbed environment) and Čečejovce (Eastern Slovakia; highly disturbed environment). Eleven elements have been analyzed (essential elements: calcium, zinc, magnesium, selenium, iron, copper; toxic elements: arsenic, cadmium, mercury, lead, nickel). Samples of feed and milk were collected five times during the spring season and five times during the autumn season in 2016. Analysis of samples was performed in Eurofins Bel/Novamann (Nové Zámky, Slovak Republic). Analyses were performed by atomic absorption spectroscopy and atomic emission spectrometry. The obtained values of the individual elements in the feed and milk were evaluated by Student's t test. Significantly higher contents of essential elements Ca, Zn, Fe, Mg, and Cu were found in the feed of dairy cows in Čečejovce (P < 0.001). Significantly higher (P < 0.001) As and Ni content in feed in Čečejovce in autumn season was also recorded. However, the content of these elements in feed did not affect their milk content. The content of Ca, Zn, and Mg in milk was significantly (P < 0.001) higher in Novoť in both investigated seasons. Some essential elements and toxic elements in feed and milk were below the LOQ (limit of quantification). Reduced content of Ca and Zn in milk in both farms compared with optimal limits, decreased Ca and Mg content in feed in Novoť, and a significant increase of Ca and Mg in feed in Čečejovce in autumn season were found. It can be concluded, due to the low content of toxic elements on these farms, that the use of milk of dairy cows from these areas for direct use or for dairy product processing is appropriate and poses no health risk to the consumers.

Bioaccumulation of selected heavy metals and histopathological and hematobiochemical alterations in backyard chickens reared in an industrial area, India

This study was carried out to determine the concentrations of four heavy metals, cadmium (Cd), lead (Pb), copper (Cu), and cobalt (Co), and histopathological lesions in tissues of chickens reared in an industrial area of West Bengal, India. In particular, Mejhia Block was selected as a heavy metal-exposed area and Vatar Block (120 km away from industrially polluted areas) as a reference site. Samples were collected from the backyard chickens in these areas. Concentrations of heavy metals in soil, water, feedstuffs, tissues (liver, kidney, spleen, lung, and muscle), and droppings were greater (p < 0.05) in the polluted site than in the reference site. The greatest tissue concentrations of Cd and Pb were noted in the kidney, followed by the liver, lung, spleen, and muscle, whereas Cu and Co concentrations accumulated in these tissues resulted in the following: liver > kidney > lung > spleen > muscle. Heavy metal concentrations were greater in older chickens (> 1 year) than in young chickens (< 1 year). Packed cell volume, total erythrocyte counts, hemoglobin, total protein, and total leucocyte counts were significantly (p < 0.01) lower in the blood picture of chickens in the exposed area. Different serum enzymes and biochemical profiles were altered due to heavy metal exposure. Histological changes revealed necrotic lesions and tubulitis in the kidney, degeneration and necrosis in liver parenchyma, and periarteriolitis, peribronchiolitis, and presence of hemosiderin pigment in the lung of chickens in the exposed site. Results indicated that backyard chickens in heavy metal-exposed site may show pathological lesions in different tissues due to accumulation of heavy metals, and thus, the consumption of chicken meat from the industrially exposed site may pose a potential health risk to local residents of polluted sites.

Application of in-plant control measures in some Egyptian micro-scale dairy enterprises and its impact on heavy metal contents of their products

Egypt is encouraging micro-scale enterprises as proved to be one of the most important reasons of economic growth. Most of the annual milk production is processed in micro-scale dairy enterprises located in squatter areas with high health risks and negative environmental impact. The aim of this study was to assess the effectiveness of in-plant control measures in controlling lead and cadmium levels in dairy products from nine Egyptian micro-scale enterprises. The results revealed that white cheese enterprises had the highest mean lead and cadmium contents; both in their raw milk (0.712 and 0.134 mg/L, respectively) and final products (0.419 and 0.061 mg/kg). Higher compliance percentages were found with cadmium levels specified in the Egyptian standards than with lead levels and ranged from 59.4% in raw milk to 100% in dry milk for cadmium levels and from 8.3% in white cheese to 66.7% in ice cream for lead; moreover, none of the collected raw milk samples were complying with the lead levels. After implementation of in-plant control measures, lower lead levels were found in all samples with reduction percentages ranging from 35.2% in raw milk from the ice cream enterprises to 73.2% in yoghurt; moreover, higher percentages of samples complied with cadmium levels. This study highlights the urgent need for applying in-plant control measures to the Egyptian micro-scale dairy enterprises to improve both safety and quality of their products.

Accumulation and Depletion of Cadmium in the Blood, Milk, Hair, Feces, and Urine of Cows During and After Treatment

The objective of this study was to assess the accumulation and depletion of cadmium in the blood, milk, hair, feces, and urine of Holstein cows during and after treatment. Three Holstein cows received daily oral cadmium administrations (as cadmium chloride) of 0.182 mg/kg body weight/day for 21 days followed by a 63-day withdrawal period. Blood, milk, hair, feces, and urine were collected during treatment and withdrawal periods. Cadmium concentrations were measured by inductively coupled plasma mass spectrometry (ICP-MS). Cadmium concentrations in blood (0.61-1.12 μg/L), milk (0.39-1.04 μg/L), and urine (0.41-2.05 μg/L) were low. Comparatively, cadmium concentrations in feces were higher, especially on treatment day 14 (20.11 mg/kg dry matter). Fecal cadmium concentrations decreased to baseline levels (0.12 mg/kg dry matter) on withdrawal day 21. Hair cadmium concentrations increased with treatment, reaching the highest levels on withdrawal day 7 (24.33 μg/kg). Most of the cadmium was excreted via the feces and very little was present in urine or milk. Cadmium residues were detected in blood and milk more than 63 days after cadmium withdrawal. Hair cadmium concentrations may reflect exposure to the metal.

Alterations in antioxidant defense system of workers chronically exposed to arsenic, cadmium and mercury from coal flying ash

Humans are exposed to different stress factors that are responsible for over-production of reactive oxygen species. Exposure to heavy metals is one of these factors. The aim of the study was to analyze the effect of chronic exposure to heavy metals through coal flying ash on the efficiency of antioxidative defensive mechanisms, represented by the activity of superoxide dismutase, glutathione peroxidase and ascorbic acid. Nonessential elements such as arsenic and mercury levels showed a significant increase (p > 0.001) in the power plant workers rather than in the control subjects. There were no significant differences of blood cadmium between power plant workers and control subjects. We found a significant positive correlation (p < 0.05) between BAs/SZn (r = 0.211), BAs/BSe (r = 0.287), BCd/SCu (r = 0.32) and BHg/BSe (r = 0.263) in the plant workers. Red blood cell antioxidant enzymes and plasma ascorbic acid were significantly lower in power plants workers than in the control group (p < 0.002). We can conclude that levels of mercury, arsenic and cadmium in blood, despite their concentration within the reference values, significantly affect plasma ascorbic acid concentration, superoxide dismutase and glutathione peroxidase activity, which are able to increase the risk of oxidative stress.

Metal concentrations and histopathological changes in goats (Capra hircus) reared near an industrial area of West Bengal, India

The present investigation was performed to assess the concentrations of four heavy metals-lead (Pb), cadmium (Cd), copper (Cu), and cobalt (Co)-in goats reared in the vicinity of an industrial area of West Bengal, India, including soil, water, and feedstuffs; tissues of liver, kidney, lung, spleen, and muscle; and milk and faeces. In addition, histopathological changes in liver, lung, kidney, spleen, and muscle samples were examined. Mejia block as an industrial polluted site and Vatar block as a reference site (without any industrial activities and 120 km away from the polluted site) were selected for this study. The results showed that concentrations of these heavy metals in soil, water feedstuffs, all tissues, milk, and faeces were greater (P < 0.05) in the polluted site than the reference site. The largest concentrations of Cd and Pb were found in kidney followed by liver, lung, spleen, and muscle. However, Co and Cu accumulations in the tissues were in following order: liver > kidney > lung > spleen > muscle. Concentrations of heavy metals were greater in older animals than in young ones. Haemoglobin, total protein, packed cell volume, total erythrocyte counts, and total leucocytes counts were significantly (P < 0.01) decreased in blood of goats in the polluted site compared with the reference site. Serum glucose, creatinine, aspartate amino transferase, alanine amino transferase, and alkanline phosphatase were significantly (P < 0.05 to P < 0.01) increased. Histological examination showed several pathological alterations including degeneration, vacuolation, and tubulitis in kidney; congestion, degeneration, periportal necrosis, and focal haemorrhages in liver; and congestion and diffuse haemorrhage in lungs. It was concluded that natural exposure to these environmental heavy metals significantly increases toxic heavy-metal concentrations in several visceral organs resulting in pathological changes in these tissues. Thus, consumption of the meat of goats reared in the polluted site may pose human health hazards.

Changes in blood metals, hematology and hepatic enzyme activities in lactating cows reared in the vicinity of a lead-zinc smelter

The present study examines blood metals levels and health parameters in dairy cows reared in areas around a Pb-Zn industrial complex located near the city of Zanjan-Iran. Blood samples (n = 27) were collected from cows reared around the smelter. Blood samples (n = 25) were also collected from cows reared in areas where chances of Pb contamination of soil, water and fodder do not exist, to serve as reference. The mean blood Pb level in cows around the smelter (1.09 ± 0.26 µg/mL) was higher than the cows from the reference area (0.72 ± 0.25 µg/mL). Hematocrit (PCV) levels decreased in cows reared in the near of smelter (24.37 % ± 2.22 %) compared to the reference site (27.54 % ± 2.87 %). Hemoglobin (Hb) concentration and mean corpuscular Hb concentration value in cows from the area around the smelter were statistically lower than the cows reared in reference area. Activities of alanine transaminase and aspartate aminotransferase (IU/l) were significantly higher in cows around the smelter as compared to reference animals.

The impact of lead and cadmium on selected motility, prooxidant and antioxidant parameters of bovine seminal plasma and spermatozoa

The aim of this study was to investigate the effects of lead (Pb) and cadmium (Cd) content on basic motility characteristics (motility-MOT, progressive motility-PROG) as well as selected markers of the prooxidant-antioxidant balance (catalase-CAT, glutathione-GSH, malondialdehyde-MDA) in bovine seminal plasma and spermatozoa. Twenty five semen samples were collected from breeding bulls and used in the study. Motility analysis was carried out using the Computer Assisted Sperm Analysis (CASA) system. The samples were centrifuged, fractions of seminal plasma and spermatozoa were separated, lysates were prepared from the sperm cell fractions. Pb and Cd concentrations were determined by the voltametric method (ASV), antioxidants and MDA were analyzed by UV/Vis spectrophotometry. The analysis showed that the average concentration of Pb in the seminal plasma was 0.23 ± 0.02 μg/mL, while its amount in the sperm cells was significantly higher (0.41 ± 0.07 μg/mL; P < 0.05). The average Cd content in bovine seminal fractions was similar and non-significant: 0.09 ± 0.01 μg/mL in the seminal plasma and 0.11 ± 0.01 μg/mL in spermatozoa (P > 0.05). The correlation analysis revealed that both heavy metals were significantly negatively correlated with MOT and PROG (P < 0.05; P < 0.01; P < 0.001), CAT (P < 0.05; P < 0.01) as well as GSH (P < 0.05; P < 0.01) but significantly positively associated with MDA as the marker of lipid peroxidation (P < 0.05; P < 0.01). Moreover the samples were categorized in three quality groups (Excellent, Good, Moderate) according to their motility values. The lowest Pb, Cd and MDA concentrations but the best antioxidant characteristics were found in samples of the best quality, moderate quality samples exhibited the highest Pb, Cd and MDA content together with the worst antioxidant capacity. This study demonstrates that Pb and Cd are serious toxic elements, which are able to increase the risk of seminal oxidative stress development and a subsequent decrease of male fertility.

Selected heavy metals versus antioxidant parameters in bull seminal plasma - a comparative study

To investigate the effects of lead (Pb) and cadmium (Cd) content on basic motility characteristics (motility, progressive motility) and selected antioxidant parameters (total antioxidant status - TAS, superoxide dismutase - SOD, albumin - ALB) in the bovine seminal plasma semen samples were collected from breeding bulls and used in the study. Motility analysis was carried out using the Computer Assisted Sperm Analysis (CASA) system. Subsequently, the samples were centrifuged and fractions of seminal plasma were collected. Pb and Cd concentrations were determined by the voltametric method (ASV), antioxidant parameters were analyzed by UV/VIS spectrophotometry using commercial kits. The analysis showed that the average concentrations of the trace elements were 0.57 ± 0.01 μg/mL for Pb and 0.11 ± 0.01 μg/mL for Cd. The correlation analysis revealed that both heavy metals were negatively correlated with motility (r = -0.777; P < 0.001 for Pb and r = -0.786; P < 0.001 for Cd), progressive motility (r = -0.763; P < 0.001 for Pb and r = -0.792; P < 0.001 for Cd), TAS (r = -0.375; p > 0.05 and r = -0.334; P > 0.05, respectively), SOD (r = -0.746; P < 0.001 and r = -0.537; P < 0.05, respectively) as well as with ALB (r = -0.609; P < 0.01 and r = -0.699; P < 0.001, respectively). Moreover the samples were categorized in three quality groups (Excellent, Good, Medium) according to their motility values. The lowest Pb and Cd concentrations but the best antioxidant characteristics were found in samples of excellent quality, medium quality samples were described by the highest Pb and Cd concentration and the worst antioxidant power. This study demonstrates that Pb and Cd are serious toxic elements, which are able to increase the risk of oxidative stress development and a subsequent decrease of semen quality.

Oxidative stress in lead and cadmium toxicity and its amelioration

Oxidative stress has been implicated to play a role, at least in part, in pathogenesis of many disease conditions and toxicities in animals. Overproduction of reactive oxygen species and free radicals beyond the cells intrinsic capacity to neutralize following xenobiotics exposure leads to a state of oxidative stress and resultant damages of lipids, protein, and DNA. Lead and cadmium are the common environmental heavy metal pollutants and have widespread distribution. Both natural and anthropogenic sources including mining, smelting, and other industrial processes are responsible for human and animal exposure. These pollutants, many a times, are copollutants leading to concurrent exposure to living beings and resultant synergistic deleterious health effects. Several mechanisms have been explained for the damaging effects on the body system. Of late, oxidative stress has been implicated in the pathogenesis of the lead- and cadmium-induced pathotoxicity. Several ameliorative measures to counteract the oxidative damage to the body system aftermath or during exposure to these toxicants have been assessed with the use of antioxidants. The present review focuses on mechanism of lead- and cadmium-induced oxidate damages and the ameliorative measures to counteract the oxidative damage and pathotoxicity with the use of supplemented antioxidants for their beneficial effects.

Effects of exposure to heavy metals on viability, maturation, fertilization, and embryonic development of buffalo (Bubalus bubalis) oocytes in vitro

The aim of the present study was to examine the effect of heavy metals, cadmium and lead, on buffalo oocyte viability and in vitro development. Oocytes were aspirated from ovaries of slaughtered buffaloes. Only viable and metabolically active oocytes with more than three layers of cumulus cell layers and homogeneous ooplasm were selected. Effects of nine concentrations (0, 0.005, 0.05, 0.5, 1.0, 1.5, 2.5, 5, and 10 microg/mL) of cadmium or lead on buffalo oocyte viability, morphological abnormities, maturation, and embryonic development in vitro were studied. Oocytes were cultured for 24 h and then checked for viability (0.05% trypan blue staining for 2 min), morphological abnormalities, and reduction assay by MTT test in experiment 1. The doses of cadmium and lead causing 100% oocyte death (1-day culture) were determined (experiment 2). In experiment 3, viable oocytes were matured in vitro in media containing different levels of cadmium or lead and then inseminated in vitro with frozen-thawed spermatozoa, and the resultant cleaved embryos were cultured in a control embryo culture medium for 8 days. In experiment 4, oocytes were cultured in control oocyte maturation medium, then fertilized, and the resultant embryos were cultured in media containing different levels of cadmium or lead for 8 days. The number of cells in the trophectoderm and inner cell mass (ICM) and the total cell counts (TCN) of blastocysts derived by in vitro culture of two- to four-cell-stage embryos (produced in control medium) in media containing 0, 0.005, 0.05, 0.5, and 1.0 microg/mL of cadmium or lead were analyzed by differential staining technique (experiment 5). Cadmium and lead were found to have a dose-dependent effect on viability, morphological abnormities, maturation, cleavage and morula/blastocyst yield, and blastocyst hatching. A significant decline in viability of oocytes was observed at 1.0 mg/mL cadmium or lead compared to the control group. The doses of cadmium and lead causing 100% oocyte death (1-day culture) were 18 and 32 microg/mL, respectively. Cadmium and lead at 1.0 and 2.5 microg/mL, respectively, caused a significant reduction of maturation of oocytes compared to the lower concentrations. No cleavage or morulae/blastocysts were produced when the oocytes/embryos were cultured in media containing 2.5 and 5.0 mg/mL of either cadmium or lead, respectively. Similarly, no morulae/blastocysts were produced from cleaved embryos cultured in media containing 2.5 and 5.0 microg/mL cadmium and lead, respectively. The developmental block, degeneration, and asynchronous divisions were higher in embryos exposed to cadmium than in those exposed to lead. TCN and number of cells in ICM were significantly lower in blastocysts derived from two- to four-cell-stage embryos cultured in media containing heavy metals. In conclusion, cadmium and lead lowered the viability and development of buffalo oocytes but at a concentration higher than that estimated in the body fluids and environment. Cadmium was found to be more ovotoxic than lead.

Milk trace elements in lactating cows environmentally exposed to higher level of lead and cadmium around different industrial units

The present investigation was carried out to assess the trace mineral profile of milk from lactating cows reared around different industrial units and to examine the effect of blood and milk concentration of lead and cadmium on copper, cobalt, zinc and iron levels in milk. Respective blood and milk samples were collected from a total of 201 apparently healthy lactating cows above 3 years of age including 52 cows reared in areas supposed to be free from pollution. The highest milk lead (0.85+/-0.11 microg/ml) and cadmium (0.23+/-0.02 microg/ml) levels were recorded in lactating cows reared around lead-zinc smelter and steel manufacturing plant, respectively. Significantly (P<0.05) higher concentration of milk copper, cobalt, zinc and iron compared to control animals was recorded in cows around closed lead cum operational zinc smelter. Analysis of correlation between lead and other trace elements in milk from lactating cows with the blood lead level>0.20 microg/ml (n=79) revealed a significant negative correlations between milk iron and milk lead (r=-0.273, P=0.015). However, such trend was not recorded with blood lead level<0.20 microg/ml (n=122). The milk cobalt concentration was significantly correlated (r=0.365, P<0.001) with cadmium level in milk and the highest milk cadmium (>0.10 to 0.39 microg/ml) group had significantly (P<0.05) increased milk cobalt. It is concluded that increased blood and milk lead or cadmium level as a result of natural exposure of lactating cows to these environmental toxicants significantly influences trace minerals composition of milk and such alterations affect the milk quality and nutritional values.

Changes in plasma hormones profile and liver function in cows naturally exposed to lead and cadmium around different industrial areas

The present study was carried out to assess the endocrine status and liver function in adult cows reared in polluted environment around different industrial units in India. The effect on endocrine system was examined by determination of plasma level of thyroid hormones, thyroxin (T4) (n=269) and triidothyronin (T3) (n=269), stress hormone cortisol (n=266), and reproductive hormones such as estradiol (n=84) and progesterone (n=84) in cows (>3 years) reared around different polluted industrial and non-polluted areas. The respective blood lead and cadmium concentration was also determined in all the cows. The mean plasma levels of both T3 and T4 were significantly (P<0.05) higher around lead zinc smelter (2.43+/-0.26 and 41.1+/-2.9nmol/L) and closed lead cum operational zinc smelter (1.81+/-0.16 and 42.4+/-6.2nmol/L), where the mean blood lead level (0.86+/-0.06 and 0.51+/-0.09mug/ml) was also significantly higher than that of cows (0.07+/-0.01mug/ml) from unpolluted areas. Regression analysis of data from 269 cows revealed a significant (P<0.01) positive correlation between the blood lead and plasma T3 (r=0.287) and T4 (r=0.173). The correlation between thyroidal hormones and the blood cadmium concentration (r=-0.079 and -0.48; P>0.05) was not significant. Plasma cortisol level had also a non-significant (P>0.05) correlation (r=-0.092) with blood lead level.However, the mean cortisol level (4.02+/-1.96nmol/L) of cows in phosphate rock mining areas was significantly (P<0.05) higher than that of controls (1.98+/-0.70nmol/L). The mean plasma estradiol level was significantly (P<0.05) higher in cows around closed lead cum operational zinc smelter (47.1+/-19.5pg/ml) than that of the control animals (21.8+/-3.9pg/ml) and in rest of the areas, the difference did not reach the statistical significance (P>0.05). The serum biochemical analysis in 36 cows around lead-zinc smelter with the highest mean blood lead level (0.86+/-0.06mug/ml) amongst all the industrial/urban areas surveyed, and in 15 animals from non-polluted areas revealed a significant positive correlation between blood lead and serum ALT (alanine transaminase) (r=0.688, P<0.01) and AST (aspartate transaminase) (r=0.390, P<0.01) and a negative correlation with serum total lipids (r=-0.337, P<0.05), total protein (r=-0.449, P<0.01) and albumin(r=-0.662, P<0.01). It is concluded from the study that the natural exposure to lead in polluted environments disturbs the endocrine profile and the higher blood lead level alters serum biochemical parameters indicative of liver functions.

Tail hair as an indicator of environmental exposure of cows to lead and cadmium in different industrial areas

This study examines the use of tail hair from cows as a possible biomarker of environmental exposure to lead and cadmium around different industrial areas. Respective blood and tail hair samples were collected from a total of 317 apparently healthy cows above 3 years of age. This includes 287 cows reared in industrial and urban areas and 30 cows from areas free from polluting sources. Significantly (P<0.05) higher lead and cadmium residues were recorded in hair from cows reared around lead-zinc smelter and closed lead cum operational zinc smelter. However, cows from those areas had significantly (P<0.05) higher blood lead but not cadmium concentration as compared to respective control value. Although mean blood lead concentration in cows around aluminum processing plant and urban cum small industrial areas and that of cadmium around steel processing plant were significantly (P<0.05) higher than respective control, the mean hair lead and cadmium content remained statistically (P>0.05) comparable to that of respective control values. The blood lead was significantly correlated with hair lead (r = 0.672, P<0.01) and cadmium (r = 0.309, P<0.05). There was a significant correlation between lead and cadmium concentration (r = 0.610, P<0.01) in hair and a nonsignificant correlation between blood and hair cadmium suggesting that cadmium accumulation in hair was influenced by blood and hair lead concentrations in cows environmentally exposed to lead.

Trace Mineral Profile in Blood and Hair from Cattle Environmentally Exposed to Lead and Cadmium Around Different Industrial Units

The present investigation was carried out to assess the trace mineral profile in blood and hair from cows environmentally exposed to lead and cadmium and to examine if these toxic heavy metals in blood and hair could affect blood copper, cobalt, zinc and iron concentrations and their accumulation in hair. Respective blood and tail hair samples were collected from adult cows above 3 years, reared in different industrial localities. Samples were also collected from urban areas with small industrial units (n = 55) and areas supposed to be free from pollution. The concomitant exposure of animals to both the heavy metal pollutants was not recorded in either of the industrial or urban locality. Blood lead was significantly (P < 0.01) correlated with blood copper (r = -0.339), cobalt (r = -0.224) and iron (r = -0.497). The increasing blood lead concentrations, irrespective of area of collection of samples, was associated with declining blood copper and iron, and cows with blood lead level above 0.60 mug/ml had significantly (P < 0.05) lower blood copper and iron. The higher blood lead but not cadmium significantly influenced the accumulation of lead (r = 0.323, P < 0.01) and cadmium (r = 0.204, P < 0.01) in hair possibly leading to significantly (P < 0.05) higher accumulation of both lead and cadmium in hair from cattle around lead-zinc smelters and closed lead-cum-operational zinc smelter, where blood cadmium level was comparable with that from unpolluted area. Concentration of zinc (r = 0.237, P < 0.01) and iron (r = 0.183, P < 0.01) but not copper and cobalt in tail hair was significantly influenced by their respective blood concentration. Both the hair lead and cadmium had a significant (P < 0.01) positive correlation with hair copper (r = 0.234, 0.294), zinc (r = 0.489, 0.775), and iron (r = 0.385, 0.643) concentrations. Thus, it is concluded from the present study that the higher blood lead concentrations in cattle irrespective of locality/industrial operations areas affected trace elements profile in blood and hair.