Water Erosion, its Relationship to Total Suspended Solids and Water Quality in the Lower Basin of the Usumacinta River, Tabasco, Mexico

Abstract

Total suspended solids are an indicator of material constituted by sedimentable solids, suspended solids, and colloidal, whose origin is erosion, wastewater discharges, and agricultural waste. The objective of this research was to determine territorial water erosion, its relation with total suspended solids, and the water quality in the lower basin of the Usumacinta River in Tabasco. Three sampling points were established, located in the municipalities of Tenosique, Emiliano Zapata, and Jonuta, in the state of Tabasco. Water samples were collected during 12 monthly sampling campaigns in an annual cycle, and the total suspended solids were determined according to the provisions of the NMX-AA-034-SCFI-2015 standard. Water erosion was calculated based on the Universal Soil Loss Equation (USLE) and with the use of geographic information systems (GIS). The results obtained were statistically analyzed, finding that the measured maximum TSS concentrations are 130.92 mg.L-1 in Boca del Cerro, 165.28 mg.L-1 in Chablé, and 113.91 mg.L-1 in Jonuta which are within the permissible concentrations for protection of freshwater aquatic life and agricultural irrigation according to ecological criteria of water quality (CE-CCA-001/89), in Mexico. The lower basin of the Usumacinta River has areas with extreme erosion (990 tons.ha-1yr-1), with conditions that accelerate the erosion process, such as annual rainfall between 1805 mm and 2250 mm, clay soils located on slopes greater than 16%, and agricultural soils. These events cause loss of the soil fertile layer where agriculture is developed, also giving rise to the accelerated transport of suspended solids; which negatively alter the quality of the water of the Usumacinta River.