Chemical and isotopic characterization of produced water from the Permian Basin: Environmental implications and lithium recovery potential

This study characterizes the chemical and isotopic composition of produced water from the Permian Basin to evaluate environmental quality and resource recovery potential. Analyses of dissolved samples included major and trace elements, dissolved organic carbon (DOC), total dissolved nitrogen (TDN), and water isotopes (δ²H and δ¹⁸O). Produced water chemistry varied across sites, reflecting geological and operational factors. Water isotopic values averaged -16.91±1.24‰ (δ²H) and 3.83±1.19‰ (δ¹⁸O), suggesting multiple water sources. Concentrations of DOC ranged from 7.5 to 96.5 ppm (mean 38.52±23.53 ppm) and TDN varied from 216 to 559 ppm (average 460±208 ppm), far exceeding surface water levels, suggesting residual oil and nitrogen source. Major cations (Na, K, Ca, Mg) were significantly higher than seawater, with a Ca/Mg molar ratio (3.75±0.62) distinct from marine signatures. Most heavy metals were below detection limits, except Hg, Pb, and Zn at selected sites. Lithium concentrations averaged 17.83±0.23 ppm, which is 2-3 orders of magnitude above seawater highlighting resource recovery potential. These findings underscore the need for targeted treatment strategies to enable water reuse and mitigate environmental impacts, positioning produced water as a valuable resource rather than waste.