Bioaccumulation Study of Produced Water Discharges from Southeastern Brazilian Offshore Petroleum Industry Using Feral Fishes.

The main effluent of oil and gas production is the discharge of produced water (PW). Despite the potential environmental impact, the structure of oil and gas platforms can act as artificial reefs. Two species of fish, Caranx crysos and Tylosurus acus, were captured under two discharging platforms at Campos Basin, P19 and P40. A nondischarging platform, P25, was taken as reference. The highest median concentration of PAH in muscle tissue was observed for C. Crysos at P40 (219.38 ng g-1) followed by P19 (68.26 ng g-1). For T. acus, the highest median concentrations were 40.07 and 42.21 ng g-1 from P19 and P40 respectively. P25 presented the smallest recorded concentrations. The results of PAH in the muscle tissue of C. crysos enabled to distinguish the platforms with PW discharge from the platform without discharge. Trace elements concentrations reflected the background levels and were not influenced by the PW release.

Monitoring of polycyclic aromatic hydrocarbons in a produced water disposal area in the Potiguar Basin, Brazilian equatorial margin.

The Potiguar Basin has oil and gas production fields offshore and onshore. All treated produced water (PW) from these fields is discharged through submarine outfalls. Although polycyclic aromatic hydrocarbons (PAHs) are minor constituents of PW, their input into the marine ecosystem is environmentally critical due to potential ecological hazards. A 2-year monitoring program was conducted in the vicinity of the outfalls to evaluate PAH bioaccumulation in marine life from PW discharges. The study was performed using transplanted bivalves Crassostrea brasiliana and semipermeable membrane devices (SPMDs) to measure PAH concentrations via bioaccumulation and in seawater. The bioaccumulation of PAH in transplanted bivalves reached up to 1105 ng g(-1) in the vicinity of the monitored outfall. Significantly lower PAH concentrations were found in the reference area in comparison to the studied area around the outfalls. Time-integrated PAH concentrations in seawater ranged from 38 to 0.3 ng L(-1) near the outfalls and from 10 ng L(-1) to not detected in the reference area. Both measurement techniques were found to be effective for determining a gradient of descending PAH concentrations from the outfalls. In addition, this study also evaluated the bioavailability of PAH for local marine biota and provided information about the influence of PW discharges on the water quality of marine ecosystems.