Determination of Organochlorine Pesticides in Cattle Liver Obtained From Zango, Zaria. Nigeria
CHAPTER ONE
Objectives of the Study
The research was designed to achieve the following objectives:
- Determination of the physicochemical properties of liver of cattle
- Determination of organochlorine pesticide residues in the liver of cattle
- Comparison of bioaccumulation levels of the organochlorine pesticide residues in the male cattle using age and the physicochemical parameters determined as a factor of categorization. Bioaccumulation of the OCPs are expected to increase as the duration of exposure increases hence, higher concentration of OCPs are expected as the age of the cattle
- Evaluation of the intake of OCP residues through cattle liver to human beings per kilogram consumed.
- To compare results obtained to Maximum Residual Limits as set by FAO (Food and Agriculture Organization ) and WHO (World HealthOrganization)
CHAPTER TWO
LITERATURE REVIEW
Various investigations have been conducted in various countries to understand the status of organochlorine pesticides contamination in foodstuffs and its exposure to human. In previous decades, organochlorine pesticide had been used intensively for agricultural and industries purpose both in developed and developing countries, and caused significant contamination of food products.
Review of Previous Studies on OCPs in Fruits and Vegetable
In Nigeria, Adeyeye and Osibanjo (1999) determined residue levels of organochlorine pesticides in raw fruits, vegetables and tubers from markets in Nigeria. In the fruits, total HCH, aldrin and total DDT were detected in 77, 38 and 30% of all samples, respectively. In the vegetables, total HCH, HCB, total DDT and aldrin were detected from 95, 53, 50 and 30%, respectively, of all samples. Aldrin + dieldrin, total HCH, and total DDT were detected from 98, 79 and 49%, respectively, of all tuber samples. Other pesticides were below their detection limits. The average levels were generally low and none were above the FAOs maximum residue limits.
In China, a study by Odhiambo et al. (2007) determined residual levels of organochlorine pesticides (OCPs) in 34 samples of 19 varieties of vegetables collected from selected sites around Deyang city and Yanting County, Southwest China. The determinations were done using a gas chromatograph with electron capture detector (GC-ECD). The results indicated that all the vegetable samples had some levels of one or more OCPs in them. Residues of DDTs were found in 94.12% while HCHs were in 91.18% of all the samples analyzed indicating high incidence of these xenobiotics in the vegetables from the areas investigated. Among the HCH isomers, γ-
HCH was the most prevalent but β-HCH was the most abundant indicating both old and fresh inputs of HCHs. DDT metabolites p,p-DDE and p,p„-DDD were more prevalent than the parent material, p,p-DDT suggesting minimal fresh inputs of DDT. The OCPs residue levels in the vegetables were generally low (≤ 1.3 ng/g wet weight) except in one sample of green pepper (Capsicum annum L) in which the concentrations (ng/g wet weight) of o,p„-DDT (82.59), p,p„- DDE (61.41) and total DDT (148.44), all exceeded the Chinese Extraneous Maximum Residue Limit of 50 ng/g for DDTs in vegetables according to the guidelines of the Chinese quality standard for food (GB 2763-2005).
In Albania, a preliminary study by Marku and Nuro (2005) determined the concentrations of chlorinated pesticides in the sediments and some fish species of Shkodra Lake. Seven sediment stations were chosen to represent different conditions of the lake. Biota samples were taken from the fat tissue of nine fish species. The concentrations of the chlorinated pesticides (except DDTs and Lindane) were found to be generally low. The total concentration of chlorinated pesticides in sediments was lower than the average values reported for the sediments in the Adriatic Sea.
A study conducted by Barkat (2005) in Pakistan determined residue levels of insecticides in fresh fruit and vegetable samples. Six hundred and eight samples of vegetables and fruits were analyzed using high performance thin layer chromatography (HPTLC) methods. The most commonly detected residues were those of methamidophos (9.8% of 608 samples), cypermethrin (8.5%), endosulfan (4.9%), chlorpyrifos (4.4%), trichlorfon (3.3%), methidathion and methomyl (2.8%), dimethoate (2.6%) and λ-cyhalothrin(1.8%) depending on the type of insecticide being used by the grower. Of all analyzed fruit and vegetable samples (608), 250 samples (41%) contained detectable residues. Of these, 13.8% had residues that exceeded Codex maximum
CHAPTER THREE
MATERIALS AND METHODS
Materials
Blender
Analytical balance (range 0 – 120g, precision ± 0.001g) (Denver Instrument xp-200) Analytical balance (range 0 – 500g, precision ± 0.1g) (Denver Instrument xp-600) Balance (range 0 – 1,200g, precision ± 0.1g) (Denver Instrument xp-2000)
Soxhlet apparatus and Soxhlet thimble
Round bottom flasks: volumes 10ml, 50ml, 100ml, 250ml Pasteur pipette: length 150mm and 250mm
Glass bottles (sample vials with Teflon seal) Rotary evaporator (Buchi, Switzerland) Desiccators
Florisil (Merck)
Oven (Gallenkamp, England) Pipette
Muffle furnace (Carbolite, England) Quartz fiber crucible
Glass funnels
CHAPTER FOUR
RESULTS
Proximate Parameters of Liver Samples
Percentage lipid content
Tables 4.1 shows the results for the average percentage lipid content of the liver samples collected in the age groups. All results were expressed in mean ± Standard Deviation (mean ± S.D.).
CHAPTER FIVE
DISCUSSION
Discussion
Table 4.1 shows the average percentage lipid content of the liver samples for the three age groups (below 11months, between 12 -20months and above 24months) used in the research. Samples from cattle above 24months had the highest percentage lipid content. The steady increase in lipid content observed within the groups was important in explaining the observed increase in OCP concentrations observed in Table 4.5.
Table 4.2 and Table 4.3 shows the average percentage ash and moisture content of the liver samples for the three age groups (below 11months, between 12 -20months and above 24months) used in the research. Although no correlation was observed between the OCP concentrations and the percentage moisture and ash content (Table 4.6), it was important to see if a relationship existed between them.
CHAPTER SIX
SUMMARY, CONCLUSION AND RECOMMENDATION
Summary
The result obtained showed the presence of the OCPs in the Liver samples and their respective quantities. Also, proximate analysis carried out revealed the physicochemical parameters of the Liver samples.
The concentration of the OCPs were α-BHC 0.01 – 0.21 mg/kg, β-BHC 0.09 – 0.90 mg/kg, Lindane 0.05 – 0.24 mg/kg, chlorothalonil 0.04 – 0.32 mg/kg, δ-BHC 0.06 – 0.40 mg/kg,
heptachlor 0.10 – 1.12 mg/kg, Aldrin 0.26 – 0.61 mg/kg, heptachlor epoxide 0.13 – 1.16 mg/kg,
endosulfan 0.13 – 3.79 mg/kg, dieldrin 0.12 – 1.72 mg/kg, endrin 0.03 – 7.88 mg/kg, endosulfan
II 0.12 – 1.116 mg/kg, p,p‟-DDD 0.12 – 0.73 mg/kg, endosulfan sulfate 0.12 – 1.38 mg/kg, p.p‟-
DDT 0.12 – 1.20 mg/kg, lambda cyhalothrin 0.07- 0.37 mg/kg and permethrin 0.02 – 0.28 mg/kg. This result shows the high concentrations of these OCPs to be greater than their respective MRLs (5 mg/kg DDT and its metabolites, 0.2 mg/kg Aldrin and Dieldrin, 0.2 mg/kg Chlorothalonil, 0.05 mg/kg Cyhalothrin, 0.1 mg/kg Endosulfan, 0.1 mg/kg Endrin, 0.2 mg/kg Heptachlor, 0.1 mg/kg Lindane and 1.0 mg/kg Permethrin) as set by FAO/WHO in 2013.
CHAPTER SIX
SUMMARY, CONCLUSION AND RECOMMENDATION
Summary
The result obtained showed the presence of the OCPs in the Liver samples and their respective quantities. Also, proximate analysis carried out revealed the physicochemical parameters of the Liver samples.
The concentration of the OCPs were α-BHC 0.01 – 0.21 mg/kg, β-BHC 0.09 – 0.90 mg/kg, Lindane 0.05 – 0.24 mg/kg, chlorothalonil 0.04 – 0.32 mg/kg, δ-BHC 0.06 – 0.40 mg/kg,
heptachlor 0.10 – 1.12 mg/kg, Aldrin 0.26 – 0.61 mg/kg, heptachlor epoxide 0.13 – 1.16 mg/kg,
endosulfan 0.13 – 3.79 mg/kg, dieldrin 0.12 – 1.72 mg/kg, endrin 0.03 – 7.88 mg/kg, endosulfan
II 0.12 – 1.116 mg/kg, p,p‟-DDD 0.12 – 0.73 mg/kg, endosulfan sulfate 0.12 – 1.38 mg/kg, p.p‟-
DDT 0.12 – 1.20 mg/kg, lambda cyhalothrin 0.07- 0.37 mg/kg and permethrin 0.02 – 0.28 mg/kg. This result shows the high concentrations of these OCPs to be greater than their respective MRLs (5 mg/kg DDT and its metabolites, 0.2 mg/kg Aldrin and Dieldrin, 0.2 mg/kg Chlorothalonil, 0.05 mg/kg Cyhalothrin, 0.1 mg/kg Endosulfan, 0.1 mg/kg Endrin, 0.2 mg/kg Heptachlor, 0.1 mg/kg Lindane and 1.0 mg/kg Permethrin) as set by FAO/WHO in 2013.
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