Does Alumina-Refining Waste Increase the Nutrient Level in Tropical Mesotrophic Floodplain Lakes?

Several floodplain lakes of the Orinoco River have been impacted by alkaline alumina-refining waste including red mud, a by-product from the Bayer process. Some of these impacted lakes have undergone algal overgrowth, which has been detected due to the unusual green color of water and the dissolved oxygen oversaturation. Thus, we conducted sampling campaigns in impacted and non-impacted lakes to measure the concentration of nitrogen (N) and phosphorous (P) in water to detect any change in the nutrient levels.

Survey of trace metals in drinking water supplied to rural populations in the eastern Llanos of Venezuela.

To ascertain the water quality for human consumption, chemical parameters such as pH, conductivity and total dissolved calcium, magnesium, iron, aluminum, zinc, copper and manganese were measured during four sampling periods (November 2002; March, May and July 2003) in drinking water wells which supply several forest camps and rural populations located in the eastern Llanos of Venezuela. Copper levels in drinking water in November 2002 were found to be significantly higher (P<0.05) than the other assessed periods.