analysis of heavy metals in fish

Description

ABSTRACT

As a cheap source of high-quality protein, healthy fats and essential nutrients, fish is a common item in the daily diet of Nigeria populace. In this study, five different tilapia fish were sampled. Concentration of Cu, Pb, Ni, Cd, Cr and Zn were determined in water and fish samples. The analyses of metals in water and fish samples were carried out by both; furnace atomic absorption spectrometry and flame atomic absorption spectrometry. The concentration of the studied metals was also found in moderate limit. The probable source of contamination is the leaching from the drying pans into the fish samples, atmospheric deposition, anthropogenic contamination and other human activities. Periodic monitoring of trace metals in the aquatic organisms along with fish is recommended to avoid any unexpected health hazards caused by the toxic heavy metals via fish consumption.

 

 

 

 

 

 

 

TABLE OF CONTENTS

COVER PAGE

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWLEDGEMENT

ABSTRACT

TABLE OF CONTENTS

CHAPTER ONE

GENERAL INTRODUCTION

• BACKGROUND OF THE STUDY

1.2     SOURCES OF     CONTAMINATION      OF     HEAVY      METALS     ON GROUNDWATER

1.3     WELL WATER HEAVY METALS

1.4     STATEMENT OF THE PROBLEM

1.5      AIM AND OBJECTIVES

1.6     LIMITATION OF THE STUDY

CHAPTER TWO

2.0     LITERATURE REVIEW

2.1   REVIEW OF THE STUDY

CHAPTER THREE

3.0     MATERIALS AND METHODS

3.1     STUDY AREA

3.2   COLLECTION OF SAMPLES

3.3   INSTRUMENTATIONS AND APPARATUS

3.4     PREPARATION OF SAMPLES

3.5     DIGESTION OF FISH SAMPLES

3.6     ANALYSIS OF HEAVY METALS

CHAPTER FOUR

4.0       RESULT AND DISCUSSION

4.1   RESULT

4.2        DISCUSSION

CHAPTER FIVE

5.1     CONCLUSION

REFERENCES

 

 

CHAPTER ONE

1.0                                    INTRODUCTION

1.1 Background of study

Fish is widely accepted because of its high palatability, low cholesterol and tender flesh, it is the cheapest source of animal protein and other essential nutrients required in human diet (Saduku and Olademeli, 1991). Fish may be sold and/ or affordable source of animal protein for poor house hold in urban and semi urban areas (Bene and Heck, 2005). The pollution has mainly been caused by industrial processes and industrial waste, typically from rubber and oil palm mills (Tariq et al., 1996). Heavy metals may accumulate in aquatic species, enter the food chain and cause serious harm to human health when contamination content and exposure are significant (Goyer 1997; Papagiannis et al., 2004; Turkmen et al., 2005; Fenandes et al., 2007) consequently, they have been listed by the US environmental Agency (USEPA) based on their potential for human exposure and health risk (Birungi et al., 2007). The levels of heavy metal accumulation in fish depend on the growth rate, metabolism, feeding pattern and ecological requirements of a given fish species (Yilmal et al., 2005, 2010). Another factor is the difference in life history patterns among species (including tropic and geographical distribution of life stages) which influence their exposure to heavy metal (Allen – Gil and Martynov, 1995).

The harmful effect of trace metals when consumed above the recommended limit can be toxic (acute, chronic or subchronic) and heavy metals can be neurotoxic, carcinogenic, mitagenic or teratogenic. The general symptoms of human related to metal poisoning include vomiting, convulsions, paralysis, ataxia, gastrointestinal disorder, diarrhea, stomatitis, depression and pneumonia (McCluggate, 1991).

Water is one of the most important and abundant compounds of the ecosystem. All living organisms on the earth need water for their survival and growth. As of now only earth is the planet having about 70 % of water (Patil, et.al 2012).

Water is the second essential factor for life after oxygen. If this essential factor is not available, many organisms die. Human beings are not excluded from this marvelous factor. People obtain their water from different sources and water is of paramount importance especially in developing countries where water supplies still pose an issue (Allamin et.al 2015).

Heavy metals occur in the environment both as a result of natural processes as well as contaminants from human beings activities (Franc et al., 2005). Some heavy metals are known as potentially toxic include arsenic, lead, aluminium and cadmium, others are essential such as nickel, zinc and chromium (Abduljaleel and Shuhaimi-Othman, 2011). Heavy Metal has positive and negative effect on human health and surroundings (Abduljaleel et al., 2011). The accumulation of heavy metals in fish has been extensively studied and well documented. However, the research has been generally focused on the muscle tissue, while the distribution pattern among other tissues, such as liver and gills have been mainly neglected (Jaric et al., 2011).

Furthermore, the contaminants also concentrate in some of the organs of fish and can cause lethal and a range of sub lethal effects (Ozmen et al., 2008). It was known that active metabolite body parts such as liver, gill and kidney concentrate more on an amount of heavy metal than other parts like muscle (Dural et al., 2007). Fishes are often seen at the top of the aquatic food chain and may accumulate large amount of heavy metals from its environment (Mansour and Sidky, 2002). In addition, fishes are one of the most indicative aspects in freshwater ambience, for the evaluation of heavy metals pollution and health risk potential of human consumption (Papagiannis et al., 2004). Tilapia Oreochromis niloticus as commercially important fish species (Christopher et al., 2009) can survive at adverse environmental conditions because their resistance to disease is strong, their respiratory demands are slight so that they can tolerate low oxygen, high ammonia levels and wide range of salinities (Zhou et al., 1998). Tilapia fish have a greater capacity for metal bioaccumulation than tiger prawn (Mokhtar et al., 2009). Heavy metals are accumulated through different organs of the fish because of the affinity between them. In this process, all heavy metals are concentrating at a different levels in different organs of the fish body parts (Rao and Padmaja, 2000). Most studies have been concerted only on the accumulation of heavy metals in the edible part (muscle), in view of the fact that it is the main fish part that is consumed by human beings (Keskin et al., 2007). Muscle is not always a good indicator of the entire body fish contaminations and therefore, it is vital to analyze other body parts as well, such as the gills and liver (Has-Schon et al., 2006). Due to the existence of metal-binding proteins in some tissues, for an example metallothioneins in the liver can accumulate significantly higher heavy metal concentration than the muscles (Ploetz et al., 2007; Uysal et al., 2008a). The metal content in the fish dorsal muscle was estimated because of its significance for human consumption and the fish liver was also measured since this organ tends to concentrate metals, it is also a good indicator of chronic exposure to heavy metals because it is the site of metal metabolism (Usero et al., 2003). Whereas, the concentration of metals in gills represents the concentration of metals in water

(Uysal et al., 2008b). Malaysia as a developing country is facing various forms of

contaminations risk (Ahmad and Shuhaimi-Othman, 2010). Hence, the main aim of this study was to evaluate heavy metal contamination and to compare metal levels

within and between liver, gill and muscle tissues of tilapia fish (Oreochromis niloticus) in four local markets in Malaysia in February 2010.

The pollution has mainly been caused by industrial processes and industrial waste, typically from rubber and oil palm mills (Tariq et al., 1996). Heavy metals may accumulate in aquatic species, enter the food chain and cause serious harm to human health when contamination content and exposure are significant (Goyer 1997; Papagiannis et al., 2004; Turkmen et al., 2005; Fenandes et al., 2007) consequently, they have been listed by the US environmental Agency (USEPA) based on their potential for human exposure and health risk (Birungi et al., 2007)

1   .2   SOURCES  OF  CONTAMINATION    OF HEAVY     METALS        ON GROUNDWATER

Groundwater is an important source of drinking water in many nations and may be heavily contaminated in many industrialized nations by industrial waste pits, septic tanks, oil wells, landfills, etc. Aquifers supply drinking water for about 120 million Americans (Lawson, 1982) and supply a quarter of the annual water demands in the United States. They are also a major supplier of water   in   many   other countries. United States groundwater, scientists are now reporting, is increasingly threatened by pollution. Many pollutants are present at much higher concentrations in groundwater than they are in most contaminated surface supplies (Moyer, & Morita, 2000).   Also, many contaminants are tasteless and odorless at concentrations thought to be threatening human health.

According to Miller (1997), about 4500 billion liters of contaminated water seeps into the ground in the United States every day from septic tanks, cesspools, oil wells, landfills, agriculture, and ponds holding hazardous wastes.   Unfortunately, very little is known about the extent of groundwater contamination. The Environmental Protection Agency of the United States of America (USEPA) estimates one percent (1%) of the drinking water wells in the United States has contaminants that exceed the standard designed to protect human health. Although that may seem small, 1% of hundreds of thousands of wells is a large number. In fact, one study reported that at least 8000 private, public and industrial wells in the U.S are contaminated (Miller, 1997).

1.3             SURVIVAL       OF                             MICROORGANISMS OF         HEAVY       METALS   IN GROUNDWATER

Due to the long time the indigenous bacteria have had to degrade the organic matter originally     present,     subsurface     environments     contain     little     organic matter. Furthermore, when percolating through the porous media, water containing organic matter encounters attached bacteria which remove most of this organic matter. Thus, subsurface systems are oligotrophic and the intermediate aquifer flow systems are among the most oligotrophic microbial environments that have ever been described (Morita, 1997). The average concentration of Dissolved Organic

Carbon (DOC) for various types of consolidated rock aquifers ranges from 0.1 to 0.7 mg/l. Chemical analysis of the organic carbon in any environmental sample certainly does not determine what portion is available for use by the autochthonous bacteria.   Most of the organic matter in subsurface environments, other than the readily labile compounds such as free amino acids, free carbohydrates, and free fatty acids, is humic, polymeric material high in molecular mass and refractory, i.e. resistant to breakdown.   Humic substances have extremely complex structures, and can be divided into three major fractions defined in terms of their solubility in water: humic acid, fulvic acid and humin. In the subsurface environments, it can be supposed that the unavailable humic and fulvic acids make up more than 50% of the total organic carbon (Morita, 1997).

Microbes have evolved longer than any other living organism, so in all probability, the nonspore-forming heterotrophic bacteria must have developed mechanisms to survive long periods when no energy or nutrients were available. Thus, the concept of starvation – survival is fundamental for the evolutionary point of view.      In order to provide a pragmatic approach to this concept, a definition has been provided by Morita (op cit.):            ‘starvation – survival is a physiological state resulting from an insufficient amount of nutrients, especially energy, to permit growth (cell size increase) and/or reproduction’.   There are various degrees of starvation, starting with cells that just utilized the last amount of nutrients for growth, to cells that have been deprived of nutrients for long periods of time (Morita, op cit.).

1.4   WELL WATER HEAVY METALS

Well are used for a variety of purposes including exploration for mineral resources, drainage, disposal and water supply, it can be shallow deep well. Well water is stagnant it may contain a lot of clay and other mineral salt it may also contain the remains of dead organisms which might have fallen into it. It may as well be hard as a result have fallen into it. It may as well be hard as a result of the presence of lime stone on the bed, thus well water requires treatment to be suitable for both domestic and industrial uses, according to (tranal et al 1966) it may contain acid and an abundance of trace element including poisonous arsenic it occur in saturated treat called aquifer which is present nearly everywhere. Well is very where. Well is very difficult to protect from contamination because they may be polluted by surface water flow through an inadequately sealed well cover by seepage polluted ground water etc (lay and mitarb 1967) well maintenance is very important through sanitary protection maintenance of the well seal and connection, protection from surface drainage are extremely important, since detraction of well safety component may allow it to become polluted (William 1999).

1.5  STATEMENT OF THE PROBLEM

For four consecutive years since 2006, six cases of enormous floating dead fish have been reported of how heavy metals affect tilapia fish Besides the concern on biodiversity depletion, the cases also resulted in many complaints from the nearby residents regarding the unsightly phenomenon and unbearable smell. Fish are often at the top of the aquatic food chain and many concentrate large amount of heavy metals from polluted water that build up by ingestion, ion-exchange of dissolved metals across lipophilic membranes and absorption on tissue and membrane surface .

1.6   AIM AND OBJECTIVES

The aim of this study is the Analysis of heavy metals on tilapia fish such as The levels of heavy metal accumulation in fish depend on the growth rate, metabolism, feeding pattern and ecological requirements of a given fish species.

1.7   LIMITATION

Fewer samples were worked on because the study was limited to that, and the parameters were limited to nine including bacteriological analysis, which is also limited.