Integrated Assessment of Whole Effluent Toxicity Tests and Chemical Characterization of Treated Permian Basin Produced Water

Produced water (PW)
from energy extraction operations
in the Permian
basin is managed using a range of treatment, recycle, and disposal
options. There is interest in the research community to evaluate the
beneficial use of treated PW outside the oil field. The present work
provides a detailed chemical characterization of the PW that has undergone
treatment to remove salts, organics, and other constituents. The treated
PW was further evaluated using a range of whole effluent toxicity
test species, such as fish and invertebrates, terrestrial species,
and in vitro bioassays. Toxicity modeling was used to integrate analysis
of the chemical and toxicology data to estimate the relative contribution
of different chemical constituents in the treated PW. The results
indicate that ammonia is the largest contributor to the observed aquatic
toxicity in the treated PW and that other constituent classes like
hydrocarbons and metals are minor contributors to the observed toxicity
to aquatic organisms. There was no observed cytotoxicity tested with
extracts of the organic chemicals from the treated PW, which is consistent
with the aquatic toxicity tests, and the terrestrial species were
less sensitive than the aquatic species. These results can inform
management options for the treated PW including potential end-use
considerations.