Title: Effects on the zooplankton community of pollutant disposal into the Jose Antonio Alzate dam, Mexico

Authors: S. Alberto Rodriguez, Pedro Avila-Perez, Irma A. Velazquez-Olvera

Addresses: Environmental Sciences, National Institute of Nuclear Research, P.O. Box 18-1027, Col. Escandon, Deleg. Miguel Hidalgo, Mexico 11801, D.F., Mexico. ' Environmental Sciences, National Institute of Nuclear Research, P.O. Box 18-1027, Col. Escandon, Deleg. Miguel Hidalgo, Mexico 11801, D.F., Mexico. ' Environmental Sciences, National Institute of Nuclear Research, P.O. Box 18-1027, Col. Escandon, Deleg. Miguel Hidalgo, Mexico 11801, D.F., Mexico

Abstract: To study the influence of pollutants on water quality from the Jose Antonio Alzate dam in Mexico, plankton samples were taken from locations along an approximately 9 km in a downstream direction. Determinations were made of pH, dissolved oxygen, biochemical oxygen demand, transparency, conductivity, and metal levels in plankton. The dam waters were generally hard, with high levels of electrolytes to a near-neutral pH level. A geographical distribution pattern was observed of zooplankton with the highest concentrations of metals at the confluence of the dam and the Lerma river, their primary source. These values were correlated with the zooplankton taxonomic composition, suggesting that the changes in species diversity and abundance were consistently dependent on the nutrient status. A comparison of net rates of dissolved metals in the dam water indicated that zooplankton responds to changes in water quality, and is quantitatively important in the downstream transport of pollutants.

Keywords: eutrophication; planktonic life; water quality; zooplankton; pollutants; dam waters; Mexico; pollutant dispersal.

DOI: 10.1504/IJEP.2001.004918

International Journal of Environment and Pollution, 2001 Vol.15 No.5, pp.497 - 504

Available online: 19 Jul 2004 *

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