Over the past few decades, pollution of water resources due to disposal of heavy metals, especially from industrial activities, has been causing worldwide concern. Unlike organic water pollutants, which are generally susceptible to biodegradation and photodegradation, heavy metals cannot be destroyed. Heavy metals are a great threat to aquatic life even at relatively low concentrations. Some heavy metals are capable of being assimilated, stored, and concentrated in human bodies, causing erythrocyte destruction, nausea, salivation, muscular cramps, renal degradation, chronic pulmonary problems, and skeletal deformity. Transition metals such as arsenic (As), chromium

(Cr), copper (Cu), lead (Pb), and mercury (Hg) are considered to be toxic to human and aquatic life. Several methods have been employed for the removal of heavy metals in water. The widely used methods for heavy-metal uptake from aqueous solutions include chemical precipitation, membrane iltration, ion exchange, and adsorption among others. Adsorption is one of the most effective and simplest approaches for the removal of toxic and recalcitrant pollutants from aqueous systems. Several adsorbents for removal of arsenic, cadmium, and lead from contaminated waters have been reported. Adsorption is the most commonly used technique because potentially there are several materials that can function as adsorbents for heavy metals. Another adsorbent slowly gaining popularity in water treatment is polymerclay nanocomposite (PCN). This chapter looks into the possibility of using PCNs in wastewater treatment speciically for the removal of heavy metals.