Levels of Heavy Metals in Pasta Available in the Nigerian Market
Levels of Heavy Metals in Pasta Available in the Nigerian Market.
ABSTRACT
The concentrations of Ni, Mn, Cd, Cu, Zn, Pb and Cr, were determined in some pastas consumed in Nigeria, with a view to providing information on the dietary intakes of heavy metals and exposure of humans to toxic metals.
The concentrations of these seven (7) elements were determined by atomic spectrometry after nitric acid/perchloric acid digestion.
The concentrations of the metals (µg/g) in the locally manufactured pasta samples were in the following ranges: Ni (0.109 – 0.344); Mn (0.377 – 2.279); Cd (Nd to 0.011); Cu (0.115 – 0.287); Zn (0.162 – 4.846); Pb (0.315 – 0.542); Cr (0.003 – 0.178).
The concentrations of the metals (µg/g) in the imported pasta samples were in the following ranges: Ni (0.077 – 0.234); Mn (Nd – 1.118); Cd (Nd – 0.779); Cu (0.028 – 0.289); Zn (0.015 – 2.141); Pb (0.328 – 0.847); Cr (Nd – 0.125).
The estimated daily intakes of metals (µg/kg bw/day) from the consumption of local pasta were in these ranges, for noodles: (0.003 – 1.366) for generally exposed children and adults; (0.005 – 2.342) for typically exposed children and adult;
For spaghetti (0.003 – 3.382) for generally exposed children and adults; (0.005 – 6.764) for typically exposed children and adult; for macaroni: (0.007 – 6.118) for generally exposed children and adults; (0.014 – 12.236) for typically exposed children and adults.
The estimated daily intakes of metals (µg/kg bw/day) from the consumption of imported pasta were in these ranges, for noodles: (0.002 – 2.375) for generally exposed children and adult; (0.004 – 4.75)
TABLE OF CONTENTS
Title Page
Declaration
Certification
Dedication
Acknowledgement
Abstract
Table of Contents
List of Tables
List of Figures
CHAPTER ONE
- Introduction……………………………………………………………………………………………………………… 1
- Background of the Study………………………………………………………………………………………… 1
- Statement of the Problem……………………………………………………………………………………….. 3
- Objective of Study………………………………………………………………………………………………….. 4
CHAPTER TWO
- Literature Review…………………………………………………………………………………………………. 6
- Heavy Metals……………………………………………………………………………………………………. 9
- Chemical Toxicity………………………………………………………………………………………………. 10
- Preferred Minerals (Essential Minerals)………………………………………………………………… 10
- Modern Diets and Heavy Metals………………………………………………………………………….. 11
- Health Implications of Heavy Metals in Food Products………………………………………….. 12
- Pasta and Pasta Processing…………………………………………………………………………………… 14
- Pasta Raw Material…………………………………………………………………………………………….. 15
- Durum wheat and semolina…………………………………………………………………………………. 16
- Wheat Milling Operations……………………………………………………………………………………. 16
- Additives Used in Pasta………………………………………………………………………………………. 18
- The Manufacturing Process of Making Pasta………………………………………………………… 21
- Mixing and Kneading………………………………………………………………………………………… 21
- Flavoring and Coloring Pasta……………………………………………………………………………… 21
- Rolling Process of Making Pasta………………………………………………………………………….. 22
- Pasteurization Process of Making Pasta………………………………………………………………… 22
- Cutting Process of Making Pasta…………………………………………………………………………. 22
- Drying………………………………………………………………………………………………………………. 24
- Packaging…………………………………………………………………………………………………………. 24
- Quality Control………………………………………………………………………………………………….. 24
- The Health Benefits of Pasta………………………………………………………………………………… 26
- Possible Contamination Sources during Pasta Production…………………………………………………………. 27
CHAPTER THREE
- Analysis…………………………………………………………………………………………………………… 28
- Heavy Metal Analysis…………………………………………………………………………………………. 28
- Sample Collection………………………………………………………………………………………………. 28
- Washing of glass wares……………………………………………………………………………………….. 29
- Sample Preparation……………………………………………………………………………………………. 29
- Digestion of Samples……………………………………………………………………………………….. 29
- Preparation for Standard Solutions for Heavy Metal Recovery Experiments………………. 30
- Cadmium Standard Solution…………………………………………………………………….. 30
- Zinc Standard Solution…………………………………………………………………………….. 30
- Copper Standard Solution………………………………………………………………………. 31
- Manganese Standard Solution……………………………………………………………………. 31
- Nickel Standard Solution………………………………………………………………………….. 31
- Chromium Standard Solution……………………………………………………………………. 31
- Lead Standard Solution…………………………………………………………………………….. 32
- Preparation of Mixed Standard Solution……………………………………………………. 32
- Recovery Experiments…………………………………………………………………………….. 32
- Statistical Analysis……………………………………………………………………………………………… 33
- Estimation of Dietary Intake………………………………………………………………………………… 33
- Hazard Quotient (HQ)…………………………………………………………………………………………. 34
- Total Hazard Index (THI)……………………………………………………………………………………. 34
CHAPTER FOUR
- Results of Metal Analysis……………………………………………………………………………………. 35
- Recovery…………………………………………………………………………………………………………… 35
- Metal Analysis…………………………………………………………………………………………………… 36
- Statistical Analysis……………………………………………………………………………………………… 47
- Result of Statistical Analysis……………………………………………………………………………….. 47
- Estimation of Potential Health Risks…………………………………………………………………….. 51
CHAPTER FIVE
Conclusion 58
INTRODUCTION
1.1 Background of the Study
In line with industrial development; pollution in the environment, and consequently agricultural raw materials, leads to high levels of food contamination across the world from the food safety viewpoint.
Cases of environmental pollution confronted very frequently and threatening food safety is due to heavy metals.
As a result of soil, atmosphere, underground and surface water pollution, our foods and beverages are getting contaminated by heavy metals.
Heavy metals occur in all food as natural or inherent component of plant and animal tissues and fluids and also maybe present as a result of contamination or deliberate addition.
Heavy metal is a term given to a group of metals and metalloids which in their standard states have atomic density greater than 5g/cm3, usually associated with pollution and toxicological problems.
ASTDR states that heavy metals are a group of metals and semi-metals associated with contaminations and are potentially toxic.
Based on these definitions and observations, heavy metals are therefore classified as essentials if they play the basic role as components of vital biochemical or enzymatic activities in human body,
for example, Fe, Mn, Mo, Cr, V, Zn and as non-essential if they metals are classified as with no biological, chemical and physiological importance to man, for example, Cd, Pb, As and Hg.
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