ABSTRACT

Disclaimer: The opinions expressed in this manuscript are those of the authors and do not necessarily represent the opinions and/or policies of the U.S. Environmental Protection Agency.

1. INTRODUCTION

Arsenic is the 52nd most common element in the earth’s crust with an average natural abundance of approximately 1.5-3 mg/kg. It is ubiquitous in the environment, occurring from both natural and anthropogenic sources, and both may pose a threat to human health. Numerous control mechanisms for arsenic exist in the environment but the natural cycling of this element throughout the various envi-ronmental compartments (air, water, soil, and biota) is complex and poorly understood. The main sources of human exposure to arsenic are from the drinking water supply and food.