Physico-chemical assessment of waters used to irrigate agricultural lands of Amazon

Abstract

The use of pesticides / fertilizers in plantations has become a problem in maintaining the quality of surface water. Thus, the objective of this study was to evaluate the water quality for irrigation purposes in the Rio Apéu microbasin – Para. The physico-chemical parameters evaluated were: pH, DO, SAR, TDS and EC measured in situ and the metals Al, Fe, Na, Ca, Mg determined in the laboratory Evandro Chagas Institute, according to the method of APHA. The average levels of pH (5.51), OD (5.04 mg L-1) are indications of normal condition in Amazonian waters. The results of Al (332 mg L-1) and Fe (5.74 mg L -1) imply the leaching of sediments from the geological formation of the region rich in these minerals, even though they present values above what is recommended by the legislation. The Richard classification allowed us to define that the waters of the study area have low salinity and sodicity, so they are not restricted to use. Thus, the results of the water quality analysis in the watershed can be concluded that it does not offer environmental problems in the use for irrigation activity