Phytoremediation of Pb by Avicennia marina (Forsk.) Vierh and Spatial Variation of Pb in the Batticaloa Lagoon,Sri Lanka During Driest Periods: A Field Study

Batticaloa Lagoon (Sri Lanka) is subjected to significant pollution as a result of anticipated unplanned development works since the cessation of a civil war in May, 2009. This paper presents the effectiveness of Avicennia marina(Forsk.) Vierh in the phytoremediation of Pb and the variation of Pb in sediments and water in the intertidal zone under drier weather conditions. Four pristine areas and 4 mangroves cut areas within the Manmunai North Divisional Secretariat Division / Batticaloa Municipal Council areas were investigated. Pb levels in the sediments and plants were negligible at all locations (i.e., below the method detection limit of the AAS for sediments and plants which is 0.25 mg/kg dry weight and 0.5 mg/kg dry weight, respectively). However, the water environment showed significant contamination (0.17–0.29 mg/L and 0.26–0.34 mg/L in pristine areas and cleared areas, respectively), hence Pb bioaccumulation is likely in fish and other biota. Avicennia marina is not effective to phytoremediate Pb under significant saline conditions.