INTRODUCTION The past or present human activities, especially industrial, agricultural and domestic as well as, release into the environment of products and potentially dangerous substances, pollutants or contaminants known. These are released into natural environments (water and soil). Their presence, particularly in groundwater, a problem at the interface of disciplinary ecosystems and water resources. In fact, attention has turned ORIENTAL JOURNAL OF CHEMISTRY www.orientjchem.org An International Open Free Access, Peer Reviewed Research Journal ISSN: 0970-020 X CODEN: OJCHEG 2014, Vol. 30, No. (3): Pg. 1125-1132 Study of Quality of Water Pond Sebkha Oran in Period of Low-water Mark Using Physic-chemical Parameters with Chadha’s Diagram and Larson Index BOUALLA NABILA Department Civil Engineering, Laboratory Materials, Soil and Thermal, University of Science and Technology, USTOMB, Oran 31000, Algeria. *Corresponding author E-mail: nibrasnabila@yahoo.fr http://dx.doi.org/10.13005/ojc/300324 (Received: July 06, 2014; Accepted: August 06, 2014) ABSTRACT The present study deals with the physical and chemical characteristics of the water of sebkha of Oran ponds. In an attempt to study the environmental impact on water quality, fifty samples were collected and analyzed. The values obtained were compared with values recommended in water quality standards by WHO. The findings of the study show that the water resources in the study area are evolved from Mg-HCO 3 water types to Mg-Cl- water types through Mg-HCO 3 -Cl- water types. The salinization is the main source of the pollution in this basin. It is related to aquifer conditions. Key words: Salinity, Ground-water quality, Physic-chemical parameters, Piezometry, Chadha’s diagram, Larson Index. increasingly to underground aquatic environments, including groundwater and runoff in streams with the development of appropriate methods, which have been developed (Cvetkova, 1968; Boutin and Boulanouar, 1983). The study area has experienced in recent years some economic growth, particularly agricultural, after application of the National Development of Agriculture (PNDA) in July 2000. This, on the one hand, increased demand for water