1.1 INTRODUCTION
Arsenic is an element that has attracted people’s interest since ancient times. Public opinion used to consider it a powerful poison, and it is in the news again now as a result of the biggest arsenic calamity in the world, reported in Asian areas. This has led to a rediscovery of arsenic by the public, despite the fact that it has always existed in the environment as a “silent” toxin in numerous regions in the world. Every year, new areas are detected in which the presence of arsenic exceeds the levels considered normal by international organizations.
Since the discovery of arsenic contamination in West Bengal there has been apprehension about arsenic contamination in Bangladesh groundwater as well, particularly in the western border districts. The Department of Public Health Engineering (DPHE) made the first discovery by testing a few wells from Baragharia mauza of Nawabganj in 1993. (Kazi Matinuddin Ahmed, banglapedia).
As 2006, the First International Congress on Arsenic in the Environment, was held in Mexico City in 2006, focusing on “Natural Arsenic in Ground waters of Latin America”. Hence the present announcement of the Second International Congress, As 2008, with the title “Arsenic from Nature to Humans”, which will be held in Valencia (Spain) from 21 to 23 May 2008.
Arsenic is a naturally occurring element widely distributed in the earth’s crust. In the environment, arsenic is combined with oxygen, chlorine, and sulfur to form inorganic arsenic Compounds. Arsenic in animals and plants combines with carbon and hydrogen to form organic arsenic compounds. It is commonly classed as a metal (one of the so-called “heavy metals”), but it has some non-metal characteristics. Arsenic is chemically similar to Phosphorus, one of the essential components of life processes. Arsenic commonly moves around in the environment as an anion (negatively charged ion), in combination with oxygen. (ATSDR Aug, 2007).
Arsenic is sourced both from man-made (anthropogenic) and natural sources. It is used in a variety of industries including lumber, agriculture, livestock and general industries. Some natural sources of arsenic include volcanism, forest fires, ground water, hydrothermal vents, and water which is in close proximity to highly mineralised areas.
Figure -1: Arsenic affected areas of Bangladesh with different contamination level
1.2 OBJECTIVE
This project was done on the basis of two major objectives. These are-
1. To determine the level of Arsenic (As) concentration in different samples belongs to different categories (human, water, livestock, agro crop, forest crop, soil and aquatic animal) and to investigate whether the concentration is in toxic level or not.
2. To identify the possible impacts of As contamination upon these components as well as on bio diversity.
