ABSTRACT
Arsenic (As) is a ubiquitous element, and its presence in soils is due to both natural and anthropogenic inputs. The properties of some arsenic compounds have been known and used for thousands of years. Arsenic sulfide was mentioned by Aristotle in the fourth century B.C., and Discorides first named it arsenicum in the first century A.D. (1). Arsenic compounds have been used for extremely varied purposes: as medicine, poison, insecticide, herbicide, fungicide, and recently, to produce semiconductors. The ancient Greeks used As as a medicine (2), and for many years Flower's solution (containing https://www.w3.org/1998/Math/MathML"> 1 % https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429080050/6559e41b-64b9-4256-96a3-5980cbb6d757/content/eq4846.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/> As trioxide) was one of the most frequently dispensed medicine in Western countries (3). Calcium and lead arsenates were the most commonly used insecticides at the beginning of this century, until the advent of organic pesticides in the 1940s (4). Arsenical herbicides such as monosodium methylarsine (MSMA), disodium methylarsine (DMSA), and cacodylic acid were largely produced in the mid-1970s (5). The organic arsenicals are still registered in the United States as herbicides (6). While the use of arsenical insecticides and herbicides has substantially decreased during the last decades, the utilization of As-containing wood preservatives is increasing (2).
