FRONTPAGETABLEOF CONTENTS 1.INTRODUCTION1.
1.Lead as a Toxicant and PoisonLeadhas long been studied as a toxicant due to its high potential of causingvarious detrimental health effects. Chronic lead toxicity is quite common andcan lead to irreversible health afflictions relating to the renal system,Central nervous system, and hepatic system among others.
Lead acts as an enzymeinhibitor by binding to proteins including enzymes. Organic lead compoundswhich are highly toxic are taken up easily by the human body. Chronic leadpoisoning can cause anaemia, extreme fatigue, and when it gets accumulated inhigh quantities, can cause damage to various organs of the body. 1.2.Lead contamination in fishWhilethe most studied ways of lead contamination are via paints, contaminated soiland drinking water, lead in food; specifically from lean meats and fishes isbeing increasingly looked into. Toxins released into water bodies are taken upby fishes via their feed as well as through their gills. Lead, a commontoxicant is mainly found in fish muscles, gills and the liver.
Due to bioaccumulationand biomagnifications, the lead is not degraded and passes on from thecontaminated fish to other animals that consume it, including humans. 2.REVIEW OF LITERATURE2.
1.In 2005, William G. Brumbaugh and Christopher Schmitt studied and compared theconcentrations of Cadmium, Lead and Zinc in fish from mining influenced watersof Northeastern Oklahoma. Despite mining having ceased in this region more than30 years ago, the heavy metal wastes remain widely distributed.
Liver, bloodand carcass samples from common carp, bass and catfish were analysed usingInductively coupled plasma mass spectroscopy (ICP-MS). Common carp was found tohave the highest amount of lead. 2.2.From 2011-2012, Elin Boalt, et al carried out a study on the presence of lead,mercury and cadmium in Baltic herring and perch from the Bothnian sea. Thesamples tested were dorsal muscle layer, liver and carcass homogenate. Lead wasreported most often in the carcass homogenate and liver.
2.3.Rohasliney Hashim et al studied the levels of lead, cadmium and nickel in fishcollected from the Kelatan river in 2014. The dorsal muscle tissue from 13 fishspecies was the analyte and the study was carried out using a graphite furnaceatomic absorption spectrometer.
Omnivorous fish were found to have high levelsof cadmium and nickel while carnivorous fish had the highest concentration oflead. The species O. Hassetti and T.
Maculates had lead concentrations thatexceeded FAO Malaysian Food Act and WHO guidelines. 2.4.Shovan MNH et al, in the June, 2017; conducted a study to determine the levelsof heavy metals in the various organs of 3 commonly consumed fishes inBangladesh – Catla, Pangus and Rohitausing Atomic Absorption spectrophotometry. The gill of the Pangus fish wasfound to have the highest concentration of lead (~48.
3 ppm) that had farexceeded the limits of WHO. 2.5.The concentration of heavy metals in farm sediments, feed and selected heavymetals in various tissues of farmed Pangasiushypothalamus in Bangladesh werestudied by Pritika Rani Das et al in July, 2017.
The concentration of lead,cadmium, nickel and mercury were below WHO recommended limits but theirconcentration in the gills, kidney and liver of the fish were high above thetolerable level and hence the fish are unfit for human consumption. 3.AIM AND OBJECTIVES3.1.
AimTodetermine the concentration of lead (Pb) in locally consumed biologicalproducts (fish) and if they are fit for human consumption. 3.2.Objectives3.
2.1. To standardise a spectrophotometric method forthe determination of trace amounts of lead.3.2.2. To determine and compare the lead concentrationin fish carcass homogenate and fish liver.3.
2.3. To compare UV spectophotometry and AtomicAbsorption Spectophotometry as methods for the same.
To estimate whether the samples are suitablefor food or feed based on World Health Organization – Maximum Level standard. 4.MATERIALS AND METHODS4.1.Sample collection, Storage and Preparation(Nameof fish species) was obtained from a roadside fisherwoman in Anna Nagar Westwho is frequented by the residents of the place. The particular species waschosen because ____________. The fish was kept in the deep freezer until it wasto be used for the experiment. For chemical analysis, homogenization was doneusing sodium phosphate buffer and the extract filtered.
4.2.Preparation of standard Lead SolutionsA100 mL stock solution of lead was prepared by dissolving 160 mg of lead acetatein double distilled water. The solution was standardized with EDTA using methylblue as indicator to determine the concentration of lead in it. A series ofstandard solutions ranging from 25-150 ?g of lead were prepared.