Survey of the water bodies for ecotoxic metals by laser-induced breakdown spectroscopy

Laser-induced breakdown spectroscopy (LIBS) was applied to the analysis of ecotoxic metals in water samples, an issue of major importance for environmental monitoring. Pollution in water bodies around Dhaka city, Bangladesh (Lat 23.7N, Long 90.4 E), was surveyed. Water samples were collected from Dhaka, the capital city of Bangladesh: Hazaribagh tannery area, Hatirjheel, Kamrangirchar, Dholaikhal, Sadar Ghat, and Showari Ghat. Apart from naturally occurring elements (e.g., Ca, Fe, Mg, Ti, Sr, Si, Al, Na, K, Li, and C), hazardous elements Cr, Co, and Ni were also found in these samples. To determine the concentration of chromium, we did quantitative analyses of the sample by atomic absorption spectroscopy. We found that the overall concentration of Cr is about 0.30ppm or 0.30mg/L in the Hazaribagh area in the rainy season, which is several times higher than the permissible limit of Cr (0.1mg/L by EPA and 0.05mg/L established by the World Health Organization) for drinking water. We did not detect lead in our samples, probably because the concentration of lead was below the detection limit of our LIBS system.