1.1 Introduction
Heavy metals are natural elements with atomic number greater than 20, characterized by a relatively high density (at least 5 g cm−3), and are toxic even at low concentrations (Koller et al. 2018). They are characteristically existing components found in changing variation in the environments and are part of human daily activities, they are also found in important structures and in a range of other artificial mixes (Govind et al., 2014). The activities of human have greatly impacted on some heavy metal biochemical cycles and equalization of which a great number of heavy metals have found its use in various items such as cars and batteries (Oyeleke et al., 2016).
As a prelude to other parts of this study, this chapter will discuss the background upon which this study was initiated, the statement of problems that led to this study, the Aim and Objectives of the study. Others are Significance of the study, Scope of work, Research hypothesis and questions, Limitations of the Study and Definition of technical terms.
1.2 Background of Study
Bread is a baked staple food made from wheat flour and is widely consumed in all parts of Nigeria among all socio- economic groups. Wheat flour, apart from its use in bread- making, is also used in pastries and confectionaries such as cakes, biscuits, doughnuts, etc (Tomori et al., 2015). It is similarly utilized in the creation of infant nourishments and in brewing professions as a substitution for chipped barley or maize (Doe et al., 2013). Measurable examination in Nigeria demonstrated that bread is one of the most expended nourishment types in homes, eateries and inns with dominating utilization among poor people (Oyekunle et al., 2014) and youthful ones who comprise over 70% of more than 150 million individuals in Nigeria. Bread is typically produced using low protein wheat flour and different fixings which are normally joined, including table salts, sugars, flavors, yeast and at the minimum a flour improver such as the potassium bromate (Buddrick, 2014) to better the quality.
Aside from the bromate content, materials utilized in bread making and the conditions where these pastry shops are found, are not free from fluctuating degrees of heavy metals pollutions. Heavy metal pollution could come from the crude materials utilized in bread making, or they could be included because of unhygienic states of the preparing conditions or on the grounds that sufficient careful steps are not taken to thwart cross-pollutions from other ambient sources (Oyekunle et al., 2014). The major route for humans’ exposure to heavy metals is through the food pathway (Magomya et al., 2011). Contamination of bread by heavy metals could arise from flour which may have been produced from contaminated raw materials.
Heavy metals receive specific consideration all over the world because of their universal nature and poisonous impacts even at low fixations (Tchounwou et al., 2012). There are accounts of a few instances of human infections, issues, failure and abnormality of organs because of metals’ poisonous quality (Duruibe et al., 2007). Elements such as Cadmium (Cd), Chromium (Cr) and Lead (Pb) are considered as carcinogenic, while Iron (Fe), Copper (Cu), Zinc (Zn), Nikel (Ni) and Mangenese (Mn) are considered as fundamental metals. Be that as it may, if the groupings of the later components are higher than their reasonable breaking points, they may make lethal impacts in people (Magomya et al., 2011). Individual metals show explicit indications of their poisonousness. Poisoning in Pb, Arsenic (As), Mercury (Hg), Zn, Cu and Aluminum (Al) have been involved with gastrointestinal issues, looseness of the bowels, stomatitis, tremor, hemoglobinuria causing a rust-red color to stool, ataxia, loss of motion, retching and spasm, gloom, and pneumonia (Singh, 2010).
Metals occur naturally in the earth's crust, and their contents in the environment can vary between different regions resulting in spatial variations of background concentrations. The distribution of metals in the environment is governed by the properties of the metal and influences of environmental factors (Khlifi & Hamza-Chaffai, 2010). Of the 92 naturally occurring elements, approximately 30 metals and metalloids are potentially toxic to humans, Be, B, Li, Al, Ti, V, Cr, Mn, Co, Ni, Cu, As, Se, Sr, Mo, Pd, Ag, Cd, Sn, Sb, Te, Cs, Ba, W, Pt, Au, Hg, Pb, and Bi. Heavy metals is the generic term for metallic elements having an atomic weight higher than 40.04 (the atomic mass of Ca) (Ming-Ho, 2005).
Therefore, in Enugu Metropolis where the research was carried out, the activities that was conducted is to evaluate the Bromate and Heavy Metal Contents of Different Bread Samples.
1.3 Statement of Problems
The concentration of heavy metals may very well be too low to be of significant concern, but it’s definitely a legitimate reason to avoid eating sizable portions of chocolate on a regular basis. Furthermore, because the cacao beans used to make chocolate come from all over the world, the amounts of heavy metals that they contain can vary widely. Although there’s no guarantee, certified organic chocolate is less likely to be produced from cacao beans that have been grown in a contaminated environment or exposed to contaminants during processing (Carter-Pokras et al., 2007).
The major heavy metals of concern include lead, cadmium, arsenic, mercury, copper and chromium because of their toxic impact on human health; for instance, environmental exposure to high concentrations of heavy metals has been linked with various cancers and kidney issues (García et al., 2016). Heavy metals have also greatly affected soil microorganisms and plants growth and development (Sharma et al., 2018). The presence of heavy metals in the environment has been a source of concern over the past few decades due to their persistence, potential harm and toxicological hazards (Ali et al., 2019). Besides the fact that they are non-biodegradable, they may also undergo microbial or chemical transformation (Nwidi et al., 2015). Recently, Hasani et al. (2019) and Nath et al. (2019) reported that heavy metal polluted environments activate co-selection process and cause a decrease in microbial tolerance to antibiotics due to their ability to co-regulate genes responsible for antibiotic resistance.
1.4 Aim and Objectives of Study
The aim of the study is to evaluate the Bromate and Heavy Metal Contents of Different Bread Samples in Enugu Metropolis. In achieving this aim, the following specific objectives were laid out as follows:
- To evaluate the levels of potassium bromate and heavy metals in bread and flour
- To determine the levels of exposure of these products by the people living in Enugu metropolis to the risk of potassium bromate, Zn, Pb, Mn, Cu and Co.
1.5 Significance of Study
This study will be of immense benefit to other researchers who intend to know more on this study and can also be used by non-researchers to build more on their research work. This study contributes to knowledge and could serve as a guide for other study.
Finally, this research work will be of immense importance to the researchers, since it is a practical requirement for the award of Ordinary National Diploma (OND) in Science Technology of the Institute of Management and Technology (IMT), Enugu.
1.6 Scope of Study
The study focuses on the Evaluation of Bromate and Heavy Metal Contents of Different Bread Samples in Enugu Metropolis.
1.7 Limitations of the Study
During the course of this study, many things militated against its completion, some of which are:
- Time Constraint: The time frame given to accomplish this project was very short due to school academic calendar and it was carried out under pressure which made the researcher not to implement some necessary features.
- Research material: availability of research material is a major setback to the scope of the study.
- Frequent power failure: This made the researcher append more money on fuel to ensure sustainable power.
- Financial Constraint: Insufficient fund tends to impede the efficiency of the researcher in sourcing for the relevant materials, literature or information and in the process of data collection (internet).
