Introduction

The steady increase in pollution necessitates the analysis and monitoring of toxic species that could become a serious potential hazard if not controlled.

(Van Staden and Botha, 1999). Lead is one of the most toxic elements, has an accumulative effect and is an environmental priority pollutant (Chen et al., 2005). The harmful effects on human health, caused by lead contamination, are well-known and among them, the reduction of the enzymatic activity, the kidneys function and the neuromuscular difficulties have been reported (Comitre andReis, 2005). The US Environmental Protection Agency (EPA) has classified lead as a group B2 (probable) human carcinogen (Naseri et al., 2008). Nowadays, there are legal restrictions concerning lead release to the environment. Nevertheless, it is used as a raw material in the manufacturing industry such as automotive batteries, ceramic and ink (Comitre and Reis, 2005). Furthermore, lead is a leftover of some industrial processes in the production of fertilizers and pesticides. In both cases, it could be either delivered to the environment by inadequate manufacturing processes or caused by accident (Naseri et al., 2008). The environmental and health problems arise fundamentally from the use of gasoline antiknock products and paint pigments (Nezio et al., 2004). As a consequence, the world health organization (WHO) has established the maximum allowable limit of 10 ng mL1 for lead in drinking water (WHO, 1996). It is, therefore, important to monitor the lead level in the environmental samples