Evaluation of the acute toxicity of oilfield-produced water using a recombinant luminescent Escherichia coli sensor.

Abstract

Oilfield-produced water, a byproduct of oil and gas extraction, contains organic contaminants and inorganic metals that can pose a risk to the human health and environmental safety. Luminescent bacteria are frequently utilized as bioassay species in toxicity assessments, particularly in the context of wastewater, water streams, contaminated sites, and chemical substances. Given the disadvantages associated with the reliance of marine luminescent bacteria on high salinity, herein, the luxCDABE recombinant Escherichia coli strains were employed as the bioassay species for toxicity assessment. In this study, a widespread sodium chloride (NaCl)-tolerant, pH-adaptable and steady-luminescent Escherichia coli sensor, Escherichia coli DH5a (pGENlux), was recombined. This strain exhibited a comparatively higher sensitivity to the toxicity of oilfield-produced water than the typical toxicity test species Photobacterium phosphoreum 502. In contrast to freshwater samples, the recombined luminescent E. coli sensor was a better choice to determine the toxicity of salinity-sensitive wastewater samples. In addition, depending on the chemical compositions and physicochemical parameters of the PW samples, the primary intoxicants were analyzed by correlating the toxicity values with the concentrations of arsenic and boron. The findings underscored the imperative for the employment of suitable bioassays to optimize the categorization of the produced water, with a view to reduce leakage and associated environmental hazards.