Source identification of nitrate in the upper aquifer system of the Wadi Shueib catchment area in Jordan based on stable isotope composition

Abstract

Groundwater forms the main freshwater supply in arid and semi-arid areas, and contamination of this precious resource is complicated by the slow rate of recharge in these areas. Nitrate contamination of groundwater is a global water quality problem, as it entails threat to human health as well as aquatic ecosystems. Source identification of contamination is the cornerstone and a prerequisite for any effective management program of water quality. Stable isotope composition of the dissolved nitrate (δ 15 N-NO 3 -and δ 18 O-NO 3 -) has been applied to identify NO 3 -sources and the main transformation processes in the upper aquifer system (A1/2, A4, and B2/A7 aquifers) in the Wadi Shueib catchment area, Jordan. Moreover, the stable isotope compositions of the groundwater (δ 2 H-H 2 O and δ1 8 O-H 2 O) in conjunction with the groundwater hydrochemistry were integrated to investigate the origin and evolution of the groundwater. Results revealed that groundwater in the study area is fresh and hard-very hard water, and mainly a Ca-Mg-Cl type. NO 3 -concentration was in the range of 7.0-74.0 mg/L with an average of 37.0 mg/L. Most of the samples showed concentration higher than the natural background concentration of NO 3 -(5.0-10.0 mg/L). The δ 2 H-H 2 O and δ 18 O-H 2 O values indicated that the groundwater is meteoric, and of Mediterranean origin, with a strong evaporation effect. The δ 15 N-NO 3 -values ranged between 6.0‰ and 11.3‰ with an average of 8.7‰, and the δ 18 O-NO 3 -values ranged between 1.6‰ and 5.9‰ with an average of 3.4‰. These values are in conformity with the stable isotope composition of nitrate derived the nitrification of wastewater/manure, and soil NH 4 . Nitrification and denitrification are the main transformation processes affecting nitrogen species. Statistical analysis revealed no significant differences in the δ 2 H-H 2 O and δ 18 O-H 2 O values, and δ 15 N-NO 3 -and δ 18 O-NO 3 -values for the three aquifers (A1/2, A4, and B2/A7), indicating that the groundwater of these aquifers has the same origin, and a common source of pollution.

Big Earth Data Processing Using Machine Learning for Integrated Mapping of the Dead Sea Fault, Jordan

“…The range of the topography values observed is comparable to the distribution of the most notable major topographic features in Jordan: Wadi Mujib located at the 31,4°N 35,5°E, a river canyon entering the Dead Sea from the east, Wadi Araba (Jarar et al, 1983;Atallah, 1992;Klinger et al, 1997), Wadi Shueib catchment area (Obeidat et al, 2021), a basin of the Yarmouk River, which is the largest tributary of the Jordan River on its south (Obeidat et al, 2013), Wadi Mujib (Abed, 2017), the depression of the Araba valley, situated between the Dead Sea Fault and the Gulf of Aqaba covered by alluvial and lacustrine deposits (Klinger et al, 2000a).…”

Assessment of water resources in Yarmouk River Basin using geospatial technique during the period 1980–2020

“…Using the Thiessen Polygons method, we estimated the weighted mean precipitation for YRB as 277 mm during the period 1980-2020. This is similar to the prevalent semi-arid Mediterranean conditions with the highly variable climate in Jordan (Obeidat et al, 2020). Moreover, since precipitation is one of the main climatic factors affecting water resources of a watershed (Duan et al, 2020), it's crucial to develop practices to manage scarce water resources, and increase water use efficiencies in order to conserve and sustain the already fragile water resources.…”