Fate and Fathead Minnow Embryotoxicity of Weathering Crude Oil in a Pilot‐Scale Spill Tank

Abstract

For several years now, the Natural Resources Canada research facility at CanmetENERGY Devon (AB, Canada) has been performing experiments in a pilot-scale spill tank using 1200 L of river water to examine the physical and chemical behaviors of various crude oil/water mixtures under varying water temperature regimes. Because oil toxicity can be modulated by weathering of the petroleum products, the present study aimed to assess changes in fish embryotoxicity to mixed sweet blend crude oil as it weathered at air and water temperatures of 14°C and 15°C, respectively, for 28 d. The physicochemical behavior of the oil was also monitored. Water samples were taken from the spill tank 5 times during the 28-d experiment on days 1, 6, 14, 21, and 28 and were used to perform toxicity exposures using fathead minnow embryos (Pimephales promelas). For each water sampling day, newly fertilized embryos were exposed to a serial dilution of the spill tank water, noncontaminated river water (used in the spill tank), and a reconstituted water laboratory control. Embryos were raised until hatching. Although mortality was not significantly altered by the oil contamination over the time period, malformation occurrence and severity showed concentration-dependent responses to all contaminated water collected. The results suggest that days 14, 21, and 28 were the most toxic time periods for the fish embryos, which corresponded to increasing concentrations of unidentified oxidized organic compounds detected by a quadropole-time-of-flight system. The present study highlights a novel area for oil research, which could help us to better understand the toxicity associated with oil weathering for aquatic species.

The effects of dissolved petroleum hydrocarbons on benthic organisms: Chironomids and amphipods

“…As expected, PACs and VOCs rapidly disappeared from the water column of the experimental chambers. Several studies have also observed this rapid disappearance (e.g., Lara-Jacobo et al, 2021;Redman and Parkerton, 2015;Robidoux et al, 2018) due to the hydrocarbon volatilization, sedimentation, or adhesion to the test chamber glass. Volatilization concerns the very light fractions of the hydrocarbons (Fingas, 2013;NAS, 2016).…”

“…Everitt et al (2020) when exposing the epibenthic amphipod Hyalella azteca to a water-soluble fraction (WSF, similar to WAF but excluding droplets or particulate oil) of a weathered diluted bitumen containing 1.08 μg/L total PAHs did not observe lethality. Overall, few studies have compared the toxicity of dissolved compounds in diluted bitumen with conventional oil to aquatic organisms (Berube et al, 2021;Lara-Jacobo et al, 2021) and, to our knowledge, there are none on benthic invertebrates. Most current literature on the toxicity of diluted bitumen on aquatic species is on fish (Wallace et al, 2020).…”

“…Most current literature on the toxicity of diluted bitumen on aquatic species is on fish (Wallace et al, 2020). The most recent studies have shown that diluted bitumen induce embryotoxicity, deformities, cardiotoxicity, DNA damage, and impaired reproduction in fish (Berube et al, 2021;Dew et al, 2015;Lara-Jacobo et al, 2021;Madison et al, 2017;NAS, 2016;Wallace et al, 2020).…”

Freshwater Sediment Toxicity Evaluation from Meso‐Scale Spill Tests of Diluted Bitumen and Conventional Crude

“…The use of the meso-scale spill tanks at the CanmetE-NERGY Devon facility has been described in previous studies (Lara-Jacobo et al, 2020). In short, the stainless-steel spill tank (Figure 1) is 3 × 1 × 1.5 m in length × width × height with one narrow end of the tank built at an incline to simulate a shoreline situation.…”

“…The particle size (Supporting Information, Figure S1) and mineral distribution (Supporting Information, Table S1) of the river sediment were determined using previously established protocols prior to being used in the spill tests (Lara-Jacobo et al, 2020). Both the oil dissolved and/or dispersed in the water column and the oil associated with bottom sediment were quantified using a dichloromethane extraction method.…”