Chemical Quality of Waters of the Atoyac-Verde River As It Passes Through Forest Ecosystems of Oaxaca, Mexico

Abstract In granitic regions, water salinity typically ranges from 30 to 40 mg L −1 at the surface and 300 500 for groundwater. Technogenic activity in Oaxaca has altered concentration chemical composition, which explains occurrence of salinization processes contamination natural waters. To determine physical–chemical composition Atoyac-Verde river, fifty-two samples were collected tributaries semi-deep wells basin. The pH, electrical conductivity (EC), major cations anions, total dissolved solids (TDS), residual sodium carbonate (RSC), adsorption ratio (SAR) identified. Likewise, osmotic potential (Ψπ) was evaluated, effective (ES) (PS) indexes. Results indicate that basin is bicarbonate-magnesium-calcium. Of 52 analyzed, only 2 identified high relief points presented levels alkalinity with a pH 8.1, EC 2320 µS cm , Ψπ − 0.08 MPa, SAR 3.74 (mmol c ) 1/2 RSC 0.53, ES 9.88, PS 7.79 mmol indicating restriction its use agricultural domestic activities. meso relief, did not present restrictive anthropic use, while low two use. conclusion, greatest alteration detected areas close city lesser extent adjacent riverside populations more than 2500 inhabitants.