INTRODUCTION AND LITERATURE REVIEW
Heavy metals are toxic agent. They are toxic to humans and animals. Heavy metals which establishes toxic actions to humans include; cadmium (Stohs and Bagchi,1995), lead ( Ferner, 2001) and mercury (Hawkes, 1997). Each of these has been studied in isolation for toxicity (Huton and Symon, 1986; Nriagu and Pacyna, 1988; Nriagu, 1989). But, in the eco…