Study was conducted to assess lead (Pb) and cadmium (Cd) status and its effect on blood biochemical parameters of cattle inhabiting around industrial effluent contaminated area. Blood samples (90) were collected from villages located near the industrial effluent contaminated Kali river which were divided into three areas viz Area 1(adjacent to river), Area 2(within 1km from the river) and Area 3(> 2 km from the river). Samples (11) were collected from rural locality away from the river to serve as control. The mean blood Pb and Cd levels in area 1 and area 2 were significantly higher (P<0.05) as compared to control animals. Significantly (P<0.05) higher AST, AKP activities and decreased total protein, albumin were recorded in the animals of Area1 and Area 2 in comparison to area3 and control animals. The BUN and creatinine were significantly (P<0.05) elevated in the animals of Area1 and Area2 as compared to control animals.
The developmental activities such as industrialization and urbanization carried out during the past few decades have given rise to serious problems of environmental pollution (Azmat et al., 2005). Lead (Pb) and cadmium (Cd) are the two most abundant toxic metals in the environment. Pb and Cd do not have any detectable beneficial biological roles in the body. On the contrary, their detrimental effects on physiological, biochemical, and behavioral dysfunctions in animals and humans have been documented (Kaji et al., 2004, Kramarova et al., 2005). Meerut district stands first in Uttar Pradesh and 39 in all India with about 8,244 small scale industrial units. All domestic and industrial waste water is discharged in the Kali river and used for growing fodders which in turn are used for rearing animals. The use of sewage sludge in the fodder crop has been considered as a major source of intake of heavy metals by dairy cattle (Kotwal et al., 2005). Heavy metal like lead and cadmium are the major toxic metals posing threat to human health causing illness like gastrointestinal diseases, infertility and cancer. In the local studies carried out in the recent past, toxic levels of heavy metals have been reported in the water, agricultural soil, vegetables in the Kali river area of Meerut (Kumar et al., 2014; Kulshreshtha et al., 2015; Maurya and Malik, 2016). However, no study has been carried out on the heavy metal status of cattle in the region. The present study was taken to assess the heavy metal residues in blood and their effect on biochemical profile of cattle reared in the villages in the vicinity of industrial effluent contaminated area.
Materials and Methods
The study site was located in the vicinity of polluted Kali river in which all the domestic sewage and highly toxic untreated industrial effluents of Meerut city were discharged. The toxic untreated effluents from the river are used as irrigation water by local villagers. Cattle reared in the villages situated near the river were used for the study. A total of 90 blood samples were collected from villages located near the Kali river. Based on the distance of the villages from the Kali river, they were divided into three areas viz Area 1(villages adjacent to river), Area 2(villages within 1km distance from the river) and Area 3(villages more than 2 Km from the river). A random 11 samples were collected from cattle reared in rural locality away from the river to serve as control for comparison. Blood samples were collected from cattle maintained at least for preceding 3 years in the area of study. The animals included in the study were more than 3 years of age. The animals were being given wheat straw and available green fodder along with home prepared concentrate mixture. Animals were not given mineral mixture regularly. Animals were vaccinated regularly for Foot and Mouth Disease and Hemorrhagic Septicemia. Animals were being dewormed regularly.
Blood samples were collected in nitric acid washed vials using heparin as anticoagulant. The vials were sealed immediately after collecting samples and carried to laboratory in a container packed with ice. 5 ml whole blood was used for estimation of lead and cadmium. 10 ml heparinised blood was processed for separation of plasma and stored at -20 0C for further analysis. Blood samples were wet digested with nitric and perchloric acid mixture (Kolmer et al., 1951). The toxic heavy metals, lead and cadmium in the digested samples were estimated using atomic absorption spectrophotometer (GBC Scientific) at the wave length of 217.0, 228.8 respectively with 6 mA current. Blood biochemical parameters like Aspartate Amino Transferase(AST), Alkaline Phosphatase(AKP), Total Protein, Albumin, Blood Urea Nitrogen(BUN) and Creatinine were estimated by biochemical analyzer(Star 21 plus, Biogen Scientific Ltd) using commercially available kits(Erba Transasia biomedical Ltd). The data were analyzed using analysis of variance followed by a Duncan post hoc test to determine significant difference in all the parameters recorded between groups using the SPSS/PC computer programme (Version 16, SPSS, Chicago, IL, USA). Differences with values of p<0.05 were considered to be statistically significant.
Results and Discussion
The mean values of blood lead, cadmium and biochemical parameters of cattle are given in Table 1. The mean blood Pb levels of animals of Area 1 and Area 2 were significantly higher (P<0.05) as compared to control animals. The mean blood Pb level of animals of Area 3 was not significantly different from control values. Significantly higher (P<0.05) cadmium concentration was recorded in the animals from Area1 and Area 2 as compared to Area3 and control animals (Table1).
Table 1: Blood Lead and Cadmium concentration and biochemical profile of cattle (Mean ± S.E)
|Total Protein(g/dl)||6.13± 0.04a
Figures in parenthesis indicate range, Observations with different small letter as superscript in a row differ significantly (P< 0.05),Area1- Villages located adjacent to river, Area2- Villages within 1km distance from the river, Area3- Villages more than 2 km distance from the river, Control- Villages away from the river.
In the present study, the possible sources of heavy metal content were identified as various industrial units are located in the nearby area of Meerut and the industrial effluents are dumped into Kali river without any predisposal effluent treatment. Significantly higher Pb and Cd in the blood of cattle might be due to high contents of these toxic metals in the industrial effluents of the river which is used by the local villagers for irrigation purposes (Sharma and Shukla, 2013; Maurya and Malik, 2016). These metals may have reached to the animal body through ingestion of contaminated fodder and water. It was also observed that the animals had direct access to the river water for drinking. The uptake of heavy metal residues in the soil, fodder and other herbage produced in the area along the river may have a definite role in the increased blood heavy metal concentration. Sharma and Shukla (2013) reported high level of lead (11.33ppm) and Cadmium (18.33ppm) in the waste water of Kali river. Maurya and Malik (2016) also reported high levels of Pb and Cd in water (0.34ppm, 0.024ppm) and sediments (81.53ppm, 3.38ppm) respectively in Kali river of western U.P. Animals are often exposed to toxic heavy metals which are disseminated into environment from a number of sources like distilleries, sugar, pulp and papers, fertilizer, automobile emissions, oil refineries, petro-chemicals, pesticides, tanneries, paint industries, discarded batteries (Swarup, 2002). The results of present study indicate that animal population kept in polluted area are exposed to toxic heavy metals such as Pb and Cd and may carry higher concentration of these heavy metals in the blood. Although no apparent toxicity could be seen in the animals during the present study, possibility of subclinical effects due to higher levels of Pb and Cd cannot be ruled out. In this investigation, most of the animals were apparently normal and frank clinical signs of lead and cadmium toxicity were not seen. However some animals had poor skin conditions including rough hair coat, cachexia, lameness, depigmentation, repeat breeding etc. Patra et al. (2005) and Swarup et al. (2007) reported high level of Pb and Cd in blood and hair of cattle reared around different industrial units in India.
Significantly (P<0.05) higher AST, AKP activities and decreased total protein, albumin were recorded in the animals of Area1 and Area 2 in comparison to animals of area3 and control animals. The BUN and Creatinine were found elevated in the animals of Area1 and Area2 as compared to control animals. The liver and renal biochemical parameters of animals of Area3 and control group were not significantly different (Table 1). Serum AST, AKP activities are considered as biomarker for liver functions in cattle and synthesis of albumin largely depend on the liver function status. Lead has been incriminated to induce hepatic dysfunction in experimental studies (Flora et al., 2012). Hypoalbuminemia is seen in hepatocellular liver diseases due to defective albumin synthesis. The present findings of significantly higher levels of AST, AKP activities and reduced protein and albumin clearly suggested the hepatic dysfunction in cattle with higher blood lead and cadmium levels. Lead and Cadmium induces increased protein excretion by causing tubular degeneration. Membrane damage to vital organs like heart liver, kidney causes 2 to 4 fold increase in AST. So the enzyme values higher than normal indicate some degree of tissue or cellular disruption. Cadmium bind with meatllothionein and this complex was found to cause tubular dysfunctions and liver degeneration (Godt et al., 2006). Mild changes in the kidney cause an increase in urea and creatinine. Cadmium found to exert toxic effect by inhibiting sulphydril group of enzymes. It also inhibit serum protein metabolism. It was found that cadmium induced increased protein excretion by causing tubular dysfunction (Godt et al., 2006). Similar findings of altered hepatic and renal function parameters of cattle environmentally exposed to heavy metal contamination have been reported earlier also (Swarup et al., 2007, Nisha et al., 2009)
From the present study it is concluded that there is increased level of Pb and Cd in the blood of cattle reared within 1 km distance from industrial effluent contaminated Kali River. Increased blood Pb and Cd were found to be associated with altered hepatic and renal function parameters in cattle. Data emphasize the necessity to implement measures to detoxicate and treat both the industrial and domestic effluents before being dumped into the river for reducing environmental contamination with these metals and consequent effect on human and animal health.
We are thankful to the Director, ICAR- Central Institute for Research on Cattle for providing necessary facilities to conduct research work. Assistance from the staff of State Animal Husbandry Department in collection of samples is thankfully acknowledged.