Determining water quality of the lower basin of the Usumacinta River in Tabasco, Mexico: Determinación de la calidad del agua de la cuenca baja del Río Usumacinta en Tabasco, México

Objective: The objective of this study was to determine the water quality of the lower basin of the Usumacinta River, based on its physicochemical and microbiological characteristics. Design/methodology/approach: There were taken 11 monthly samplings of surface water during the rainy season, from June to December, 2017 and in the dry season, from April to May, 2018, in three different sites. The parameters of temperature, pH, Electrical Conductivity (EC), Total Dissolved Solids (TDS), Total Suspended Solids (TSS), total phosphorus (TP) and Nitrogen nitrate (N-nitrate) were evaluated. Significant statistical differences (p≤0.05) between seasons and between sites were determined. Results: The results obtained were compared with Mexican regulations and Ecological Criteria for water quality. The parameters such as EC, TDS, TSS and total phosphorus showed substantial differences among seasons. The temperature, pH, EC and N-nitrate, did not exceed the maximum permissible limits for the use of irrigation water, urban public use and protection of aquatic life. However, the presence of E. coli and total coliforms from 530 to> 24 196 MPN/100 ml was recorded throughout the study period. Findings/conclusions: Parameters under study did not show significant differences between sites. The rainy season had an important effect on the increase in concentrations of TSS, TP, N-nitrate and total coliforms. Also, that maximum concentrations were recorded during the study period in the sampling sites of Boca del Cerro (R1) and Puente Chablé (R2).Objective: To determine the water quality of the lower basin of the Usumacinta River (Tabasco, Mexico), based on its physicochemical and microbiological characteristics. Design/methodology/approach: There were taken 11 monthly samplings of surface water during the rainy season, from June to December, 2017 and in the dry season, from April to May, 2018, in three different sites. The parameters of temperature, Hydrogen potential (pH), Electrical Conductivity (EC), Total Dissolved Solids (TDS), Total Suspended Solids (TSS), total phosphorus (TP) and Nitrogen nitrate (N-nitrate) were evaluated. Significant statistical differences (p ≤ 0.05) between seasons and among sites were determined. Results: The results obtained were compared with Mexican regulations and Ecological Criteria for water quality. The parameters such as EC, TDS, TSS and TP showed substantial differences among seasons. Values for temperature, pH, EC and N-nitrate, did not exceed the maximum permissible limits for the use of irrigation water, urban public use and protection of aquatic life. However, the presence of E. coli and total coliforms from 530 to > 24,196 MPN 100 mL-1 were recorded throughout the study period. Findings/conclusions: Parameters under study did not show significant differences among sites. The rainy season had an important effect on the increase in concentrations of TSS, TP, N-nitrate and total coliforms. Also, maximum concentrations were recorded during the study period in the sampling sites of Boca del Cerro (R1) and Puente Chablé (R2)