DETERMINATION OF METAL CONTENTS AND CHEMICAL-PHYSICAL PARAMETERS IN SEDIMENTS OF LAGUNA DE BUSTILLOS IN CHIHUAHUA, MEXICO

The Laguna de Bustillos is a priority aquatic system in Chihuahua State. This ecosystem is essential for different human activities such as fishing, but is also crucial for migratory birds and aquatic flora and fauna. The objective of this research was to determine the quantity of heavy metals in sediments of the Laguna de Bustillos located in Chihuahua, Mexico. The parameters of pH, electrical conductivity (EC) and granulometry were also quantified. A total of 56 sediment samples were collected from 28 randomly selected sampling sites. The sediment sites were close to the cities of Anahuac and Cuauhtemoc city, the community of Ejidos and Mennonite colonies. In each site two samples were collected at two depths; 0-15 and 15-30 cm. The following 17 elements were quantified Ag, As, Al, B, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Si and Zn, using an Inductively Coupled Plasma-Optical Emission Spectrometer (ICP-OES). The results were compared to standards established by Mexican, US and Canadian laws. The statistical analysis considered a factorial treatment design where factor A was the location with four levels and factor B was the depth with two levels. In general, the results showed statistical differences only for sites (P<0.05). The elements that exceeded one or more standards for sediments were: As (15.7±1.7 mg k^-1; Mennonite colonies), B (19.3±2.2 mg k^-1; Anahuac), Cd (1.2±0.23 mg k^-1; Anahuac) and Cr (46.15±2.5 mg k^-1; Cuauhtemoc). The granulometry was mostly clay (29%). The average pH was for Cuauhtemoc 9.1±0.15; for Anahuac 9.06±0.16; for Ejidos 8.6±0.1 and for Mennonite colonies 8.6±0.12. The EC means were 0.39±0.09 mS cm^-1 for Anahuac; 0.37±0.07 mS cm^-1 for Cuauhtemoc; 0.20±0.034 mS cm^-1 for Ejidos and 0.15±0.019 mS cm^-1 for the Mennonite colonies. It can be concluded that the concentrations of some elements were at levels that could damage the ecology of the area in the medium and long terms.