Speciation of Two Heavy Metals in Pastures and Animals: An Assessment of Health Risk

The aim of study was access the cobalt and lead contamination in soil, forages and animals. Heavy 12 metal pollution is a matter of prime significance in natural environment. Through food chain 13 toxicity of heavy metals and their bioaccumulation potential are transferred into humans .Higher 14 concentrations of metallic compounds are toxic to living organisms but these are essential to 15 maintain body metabolism. Intake of food crops polluted with heavy metals is chief food chain 16 channel for human exposure. Animals are exposed to heavy metal stress by the intake of richly 17 contaminated food crops those are chief part of food chain. We collected samples of soil, plant, 18 animal blood, hair and faeces to find contamination through wet digestion process in lab and metal 19 analysis. Different forages were collected to study Zn amount in forages whilst soil and animals 20 in Mianwali Pakistan. The health risk index (HRI) calculation was our major concern in this study. 21 Our present findings also emphasized on the assessment of bio-concentration factor (BCF). We 22 also calculated other significant indices i.e. Pollution load index (PLI), daily intake of metal 23 (DIM), Health Risk Index (HRI) and Enrichment factor (EF). While the experimentation result 24 showed different concentrations of metal in different seasons. When the Zn concentration in 25 forages was (32.59-42.17mg/kg) and in soil (21.82-35.09 mg/kg). Soil samples showed higher 26 level of (PLI) Pollution load index. Bio-concentration of zinc was (1.03-1.57mg/kg). It can be 27 concluded as regular monitoring of the level metal is essential evaluate the contamination status.

Macronutrients and micronutrients of all types fulfill the particular nutritious needs of animals and 64 forages. In soil-forage-animal continuum heavy metals and other mineral nutrients perform a 65 significant role in metabolic, catabolic, biochemical, biological, chemical and enzymatic activities 66 of living cell in organisms (Pais and Jones 1997). Division. Temperature of this area ranges from 47°C maximum and 19°C minimum per annum. 73 In Mianwali the maximum rain fall occur in July about 6.6mm annual mean rain fall is about 3.3 74 mm. Soil condition of this area characterize as loamy, sandy and clay soil. Pea nut, mung, mash, 75 mustard, Eruca, fennel, wheat, barley and oat are important crops. Forest cover area is very low 76 because trees are used as fuel and timber. Canal irrigation system is very less developed, only a 77 little area is irrigated with Indus river irrigation system (Ghani et al. 2016;Qureshi et al. 2007).

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Sample collection from sites 79 In district Mianwali four sites were selected for sampling. The 3 samples of agricultural soil, 80 forages and animal blood, hair and faeces were taken to examine the metal profile of soil-forage-81 animal continuum. The samples were taken from Wan bhachran site, Mianwali, Esakhel and 82 Piplan. S1 (Summer), S2 (Autumn) and S3 (Winter) was selected for sampling. The samples were 83 taken randomly from sites.

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Soil sample collection 85 In the district Mianwali four sites were selected to collect the samples. 3 samples of soil were 86 collected with equal distances in the field. Stainless steel auger was used to dig up the upper layer 87 of soil about 12-15 cm (Siddique et al. 2019). These samples were packed into plastic bags to avoid 88 the mixing of other chemical compounds into it. Samples were stored in laboratory and labeled 89 then metal analysis was performed. For each sample three composite samples were made. The collected samples were firstly air then oven drying at 72 0 C for 2 days. The samples were placed in 91 incubators at 70 0 C temperature for 5 days. Whatman filter paper of 42 µm was used. Then this prepared solution was kept in plastic bottles 133 for metal profile evaluation.

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Blood samples collected from the Mianwali district were stored and freezed at -20 0 C. For digestion 135 process the samples were from freezer and digested with same standard procedure as applied to 136 soil and forages (Siddique et al. 2019).Hair sample was sun dried and was cut into pieces of 1.0-137 2.9 cm. De-ionized water was used to wash the samples and ethanol was also applied to wash.

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Oven drying process was carried out and for 4 hours and then desiccator cooling was performed and oven dry the samples were submitted for digestion (Nicholson et al. 1999).
The prepared samples were then analyzed for metal contents by Atomic Absorption Spectrophotometer (Perkin-Elmer Corp., 1980). Nutritional minerals that were evaluated in the  The apparatus is convenient for analysis. Any radiation that is emitted by flame had no effect on 151 the working of apparatus. The absorption method is independent of the excitation potential of the 152 spectral line used. Cmetal is the concentration of metals in forages,

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Dfood intake is the daily intake of forages,

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Baverage weight is the average body weight.

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For calculating this daily intake of metal the conversion factor was taken 0.085 (Jan et al. 2010).

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Daily intake metal for cow was calculated by using animal body weight 600 kg and daily forage        and Season × Animal × Source (Table 1).

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The level of Zn in soil samples varied within range 21.82 mg/kg minimum and 35.09 mg/kg 221 maximum ( Table 2). The minimum Zn value was noticed in soil of Z. jujube in S1 and its maximum 222 value was observed in soil of Z. jujube during S3 (Fig 1). The present study had the Zn value below 223 the permissible limits of 300 mg/kg suggested by WHO /FAO (2001). 2.48 mg/kg correspondingly. The minimum level of blood was present in sheep during S1 and 237 maximum level was observed in cow blood of S3 (Table 3).The present investigation of Zn was 238 found in the range of permissible limit 1.45 mg/l as suggested by NRC (2007). The Zn level in 239 hair sample was ranged minimum to maximum 1.03-2.84 mg/kg (Fig 3). In S1 season the sheep  (Table 4).The daily intake of metal for Zn ranged from 0.048-0.081 259 from minimum to maximum. The lowest value of daily intake of metal was depicted by sheep 260 during S1 while the highest DIM was noticed in buffalo during S3.The health risk index for Zn 261 ranged from 0.160-0.272 from lower to higher values. The health risk index (HRI) was depicted 262 lowest in sheep during S1 while the highest value found in the buffalo during S3 (Table 5).

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The current concentration of Zn in soil was found lower as compared to concentration of Zn (0.83-

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The found value of daily metal intake was lower than the daily intake metal of Zn  The Zn concentration in Animals blood, hair and faeces in different seasons