Abstract:
Pollution of water, soil and air by petrochemical effluents, oil spills and gas flare
containing heavy metals is a common occurrence in oil producing areas such as Delta
State, Nigeria. The Drinking Water (DW) are thus inadvertently polluted with heavy
metals with resultant systemic poisoning of life. Ethylenediaminetetraacetic acid (EDTA)
and Activated Charcoal (AC) have the potential to reduce Heavy Metal Concentration
(HMC) in DW. However, report on theiruse as chelators when incorporated in the DW of
chickens during production is scanty. Hence, the effectiveness of EDTA and AC as
chelators in DW of chickens during management was evaluated.
Twenty-one Local Government Areas (LGA) in Delta State, were purposively selected
based on the intensity of crude oil exploration and grouped into seven zones: Urhobo,
Isoko, Ijaw, Itsekiri, Ukwani, Aniocha and Ika. Samples of DW, eggs and meat were
collected from each zone and analysed forHMC (ppm) using standard procedures, and
results were compared with World Health Organization (WHO) standards. Water
Relatively High in: Vanadium (WRHV), Cadmium (WRHC) and Iron (WRHI) were each
treated with or without either 50 mg/l EDTA or AC. One-day old Arbor Acres broiler
chicks (n=288) were randomly allotted to the treatments with four replicates in a
completely randomised design and fed for 42 days. At day 35, two chickens were selected
and housed in cages. The total excreta were collected, dried and stored. At day 42, two
chickens were randomly selected per replicate and slaughtered. Deboned thighs of
slaughtered chickens and excreta were assayedfor HMC using standard procedures. Data
were analysed using descriptive statistics andANOVA at α0.05.
Vanadium, cadmium and Iron concentrations in the DW ranged from 0.02±0.0001
(Aniocha) to 29.29±0.0042 (Itsekiri), 7.86±0.2903 (Aniocha) to 15.68±0.3900 (Urhobo),
497.80±0.0043 (Aniocha) to 2002.20±12.0031 (Isoko), respectively. In the eggs,
vanadium, cadmium and Iron concentrations ranged from 0.01±0.001 (Ika) to 0.08±0.001
(Itsekiri), 10.96±0.020 (Aniocha) to 21.03±0.032 (Urhobo) and 3060.40±4.001 (Ukwani)
to 4594.40±7.001 (Isoko), respectively. In the meat, vanadium content ranged from non detection (Ika) to 0.48±0.01 (Ijaw), cadmium ranged from non-detection (Aniocha) to
1.49±0.01 (Urhobo), while iron ranged from 1.41±0.01 (Ika) to 1.75±0.02 (Isoko). The
HMC levels were higher than WHO tolerable levels of 0.34 (vanadium), 0.01 (cadmium)
and 0.30 (iron). The EDTA reduced vanadium (25.0%), cadmium (50.0%) and iron
(11.0%) concentrations in chicken meat. Similarly, AC reduced vanadium from
0.011±0.010 to 0.010±0.001 (10.0%), cadmium from 0.052±0.031 to 0.030±0.001
(42.0%) and iron from 0.209±0.070 to 0.057±0.021 (73.0%) in chicken. Voided vanadium
of broiler on WRHV+EDTA (10.62±0.20) was significantly higher than WRHV+AC
(0.67±0.012) and WRHV (0.007±0.001). Voided cadmium ranged from 0.001±0.001
(WRHC+EDTA) to 1.100±0.100 (WRHC+AC), while iron increased from 193.66±3.001
(WRHI+EDTA) to 622.20±8.020 (WRHI+AC). Chelation by activated charcoal increased
concentration of vanadium, cadmium and iron by 99.0%, 99.0% and 17%, respectively in
excreta.
Ethylenediaminetetraacetic acid was more effective in chelating cadmium while, activated
charcoal was potent in chelating cadmium and iron in the drinking water and subsequent
lowered concentration in chicken meat. Therefore,a combination of these chelators in
drinking water of chicken is recommended.
