Assessment of the groundwater quality for drinking and irrigation purposes in the central nile delta region, Egypt

Abstract

One hundred sixty-nine groundwater samples were collected, chemically analyzed, and classified into shallow, intermediate, and deep zones to evaluate the vertical and lateral change in groundwater quality in the central part of the middle Nile Delta. To estimate the groundwater suitability for drinking, parameter’s concentrations were evaluated according to WHO drinking water guidelines to delineate the samples of desirable and undesirable range in every zone. According to the computed WQI, most part of the shallow groundwater is unsuitable for drinking [unfit (8 wells, 14.55%), very poor (3 wells, 5.45%), and poor drinking quality (26 wells, 47.3%)]. Intermediate groundwater zone is mostly suitable [excellent (4 wells, 8.9%) and good (24 wells, 53.3%)]. The deep groundwater quality is classified into unfit (3 wells, 4%), very poor (5 wells, 7%), poor water (27 wells, 40%), good quality (30 wells, 45%), and excellent (2 wells, 3%). Groundwater suitability was also evaluated using TDS, Na%, SAR, RSC, Cl, KI, PI, MH, CAI, and CR. Irrigation water quality index (IQW) was also used as an integrated method. The studied groundwater is mostly of medium suitability where a number of samples which fall within this class are 36 (65.5%), 29 (64%), and 34 (51%) for the shallow, intermediate, and deep groundwater. Water samples have good irrigation quality which increases downward where 15 (27.2%), 13 (29%), and 32 (48%) samples are recorded in this class, respectively. Samples belonging to the poor quality class are mostly located in the northern part, and its sample numbers are 4 (7.3%), 3 (7%), and 1 (1%), respectively.