Study for The Efficiency of Different Methods of Mercury Preconcentration Techniques in Aquatic Environmental Samples

Abstract

Mercury is a well known environmental pollutant and is very toxic in very low concentration. The present study is concerned with the evaluation of some methods of the hard problem of preconcentration of mercury from aqueous samples due to the very tow levels of mercury in environment which are difficult to be detected directiy.

This study in the present thesis is divided into 3 chapters.

Chapter 1: is an introductory part divided into two sections. Section A:deals with different properties of mercury such as General properties, sources to the marine environment, Hg

species, toxification, detoxification, bioaccumulaiton, toxicity, Hg distribution in atmosphere and aquatic systems, Hg in industry, policies dealing with Hg pollution, Hg threshold limit value {TLV}, fate of mercury in aquatic systems and an example for the determination of mercury in Egypt. Section B: A review of preconcentration of mercury from aquatic

samples and the methods of mercury determination.

Chapter II: deals with the experimental part and study area. Section (1):Experimental part. This includes the study of different trials with many chelating agents such as: Diphenylthiocarbazone (Dithizone) (DZ), Sodium diethyfdithiocarbamate (NaDDC) and Ammonium pyrrolidine dithiocarbamate (APDC) and loading them on the supporting materials XAD-2 or XAD-4. Then using them as Hg preconcentrating agents. The trials aimed to reach the most optimum conditions leading to the best recovery of Hg from aquatic samples putting in consideration the economicity of the chemicals used.