Integrative biomarker assessment of the effects of chemically and mechanically dispersed crude oil in Pacific oysters, Crassostrea gigas (original) (raw)
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Journal of Marine Science and Engineering, 2020
The eastern oyster Crassostrea virginica is an ecologically and economically important species that is vulnerable to oil pollution. We assessed sublethal effects of soluble fractions of crude oil alone (WAF) and crude oil in combination with Corexit 9500 dispersant (CEWAF) on oysters at three life history stages. Veliger swimming, pediveliger settlement, and adult clearance rates were quantified after 24 h exposures to the contaminants. Veliger swimming speeds were not significantly impacted by 24 h exposures to WAF or CEWAF. A larger proportion of veligers were inactive following WAF and CEWAF exposure as compared to the control, but the effect was greater for pediveligers, and pediveliger settlement in the highest concentration CEWAF treatment decreased by 50% compared to controls. Thus, pediveligers may be particularly vulnerable to oil exposure. In the adults, we found significant clearance rates reductions that persisted 33 days after acute exposure to CEWAF. Knowledge of suble...
Journal of Nigerian Society of Physical Sciences, 2022
In this study, the physicochemical characteristics of crude oil, dispersant (Ecobest) and crude oil-dispersant testsystems,and their toxicities on representative marine organismswas assessed. The test media included mechanically dispersed crude oil-in-water(MDO) and its water accommodated fraction (WAF), chemically dispersed crude oil-in-water (CDO) and its water accommodated fraction (CEWAF), the Dispersant (D), and a reference toxicant, sodium dodecyl sulphate (SDS). These test media were used to carry out toxicity studies on Tilapia guineensis, Palaeomontesafricanus, and bacteria-heterotrophic bacteria and hydrocarbon utilizing bacteria. Physicochemical characteristics of the test media were done using standard methods. The static with renewal bioassay option was employed for toxicity tests involving Tilapia guineensis and Palaeomontesafricanus, while the static without renewal option was used for microbial bioassays.Marine organisms were exposed to the following concentrations: 100%, 50%, 25%, 12.5%, 6.25% and 0% of MDO, CDO, WAF, CEWAF and D, respectively. The 96 h LC 50 and toxicity factors were determined. Results for physicochemical characteristics of the test media showed that the pH and dissolved oxygen levels were sufficient for sustaining aquatic habitation. Pb metal was present in high amounts in D, but relatively low in CDO and CEWAF. Toxicity data showed that Ecobest was non-toxic to the test organisms relative to SDS.
Comparative Toxicity of Oil, Dispersant, and Oil Plus Dispersant to Several Marine Species
Environmental Toxicology and Chemistry, 2004
Dispersants are a preapproved chemical response agent for oil spills off portions of the U.S. coastline, including the Texas-Louisiana coast. However, questions persist regarding potential environmental risks of dispersant applications in nearshore regions (within three nautical miles of the shoreline) that support dense populations of marine organisms and are prone to spills resulting from human activities. To address these questions, a study was conducted to evaluate the relative toxicity of test media prepared with dispersant, weathered crude oil, and weathered crude oil plus dispersant. Two fish species, Cyprinodon variegatus and Menidia beryllina, and one shrimp species, Americamysis bahia (formerly Mysidopsis bahia), were used to evaluate the relative toxicity of the different media under declining and continuous exposure regimes. Microbial toxicity was evaluated using the luminescent bacteria Vibrio fisheri. The data suggested that oil media prepared with a chemical dispersant was equal to or less toxic than the oil-only test medium. Data also indicated that continuous exposures to the test media were generally more toxic than declining exposures. The toxicity of unweathered crude oil with and without dispersant was also evaluated using Menidia beryllina under declining exposure conditions. Unweathered oil-only media were dominated by soluble hydrocarbon fractions and found to be more toxic than weathered oil-only media in which colloidal oil fractions dominated. Total concentrations of petroleum hydrocarbons in oil-plus-dispersant media prepared with weathered and unweathered crude oil were both dominated by colloidal oil and showed no significant difference in toxicity. Analysis of the toxicity data suggests that the observed toxicity was a function of the soluble crude oil components and not the colloidal oil.
EFFECTS OF SPIKED EXPOSURE TO AN OIL DISPERSANT ON THE EARLY LIFE STAGES OF FOUR MARINE SPECIES
Environmental Toxicology and Chemistry, 1991
Spiked exposure, continuous flow toxicity tests using the oil dispersant Corexit 9527@ were performed during the early life stages of four California marine species Test chambers containing sensitive life stages of the giant kelp (Macrocystis pyriferu), the red abalone (Haliotis rufescens), a kelp forest rnysid (Holmesimysis costata), and the topsmelt (Atherinops nffrnis) were inoculated with concentrated dispersant, then allowed to flush with clean, filtered seawater Spectrophotometric monitoring of tests showed dispersant levels diminishing to below detection limits within 5 to 6 h or less Results showed Haliotis to be the most sensitive species tested, with Afherinops being least sensitive in terms of no-observed effect concentration (NOEC) and Holmesimysis be ing least sensitive in terms of median effect concentration, Macrocystis was intermediate in both measures When spiked exposure toxicity results were compared to those of previously reported constant-exposure tests, no consistent conversion factor that might relate spiked-and Lonstant-exposure toxicity data was found
Polish Journal of Environmental Studies
Accidental oil spillages can release millions of barrels of oil into the marine environment threatening aquatic wildlife like fisheries. As a part of the oil spill response strategy, several chemical dispersants have been recommended that have been successfully used elsewhere. However, the adverse effects of dispersed oil are unknown to fish species in Kuwait. Therefore, this study investigated the toxicity of water-accommodated fraction (WAF) and chemically enhanced water-accommodated fraction (CEWAF) of Kuwait crude oil (KCO) with three dispersants (Corexit® 9500, Corexit® 9527, and Slickgone® NS) against the larvae of the sobaity sea bream Sparidentex hasta which is of an international economic significance. Total petroleum hydrocarbons (TPH) were used for comparison of chemical compounds partitioned in WAF of dispersed and non-dispersed oil. Toxicity test results with fish larvae showed that WAF of non-dispersed oil and Corexit® 9527 treated CEWAF had similar LC 50 values (0.12 g oil. l-1) whereas CEWAF's of Corexit® 9500 and Slickgone® NS CEWAF showed lower toxicity.
Comparative Toxicity of Oil, Dispersant, and Dispersed Oil to Texas Marine Species
International Oil Spill Conference Proceedings, 2001
Dispersants are one class of chemical response agents currently approved for use on offshore oil spills. However, questions persist regarding potential environmental risks of nearshore dispersant applications. To address these questions, the relative toxicity of weathered crude oil, dispersant, and weathered crude oil plus dispersant were compared. This study included one luminescent marine bacteria (Vibrio fisheri), two marine vertebrate (Cyprinodon variegatus and Menidia beryllina), and one invertebrate test species (Mysidopsis bahia). Both the vertebrate and invertebrate species were tested under spiked (short episodic) exposure regimes and 96-hour continuous exposure regimes using protocols developed by the Chemical Response to Oil Spills: Ecological Effects Research Forum (CROSERF) and U.S. Environmental Protection Agency (EPA), respectively. Toxicity to the marine bacteria was evaluated after a 15-minute exposure using the Microbics Microtox® system. Results showed no signific...
Effect of Size on the Acute Toxicity of Crude Oil to the Mangrove Oyster, Carasostrea gasar
Journal of Applied Sciences …, 2004
The acute toxic effects of a Nigerian crude oil (Egbogoro Liner II) to the mangrove oyster Crassostrea gasar were studied in bioassays. Tests were conducted over a 96-hr period after acclimatization of individuals in the laboratory, initially with a population comprising a broad size categories (11-60 mm) in range finding tests. The tests were semi-static bioassays in which the exposure media were replaced every 24 hours, at which the oysters were also examined for mortality. Subsequent experimentation was designed to compare the toxicities of oil to small (10-30 mm) and large (41-60 mm) oysters. LC 50 values were obtained by graphical interpolation. Significant differences in effects at each time interval between small and large oysters were determined using the Man-Whitney tests on percentage mortality values. Relative toxicity tests showed consistently lower mortalities for small oysters at 24-hr, 48-hr and 96-hr periods, with Mann-Withney tests showing significant differences (p<0.05) in mortality in 48 and 96 hr bioassays. The 96-hr LC 50 value for the larger oysters (135 ppm) was lower than that of the smaller ones (545 ppm), implying that smaller oysters (in the size ranges used) were more tolerant to crude oil than the larger ones. @JASEM
Marine Environmental Research, 2015
Concentration dependent differences in acute and long-term effects of a 48 h exposure to mechanically or chemically dispersed crude oil were assessed on juvenile lumpsucker (Cyclopterus lumpus). Acute or post-exposure mortality was only observed at oil concentrations representing higher concentrations than reported after real oil spills. Acute mortality was more apparent in chemically than mechanically dispersed oil treatments whereas comparable EC 50 s were observed for narcosis. There was a positive correlation between EROD activity and muscle PAH concentration for the lower oil concentrations whereas higher concentrations inhibited the enzyme activity. The incidence of gill tissue lesions was low with no difference between dispersion methods or oil concentrations. A concentration dependent decrease in swimming-and feeding behavior and in SGR was observed at the start of the post-exposure period, but with no differences between corresponding oil treatments. Three weeks post-exposure, fish from all treatments showed as high SGR as the control fish.
TOXICITY OF AN OIL DISPERSANT TO THE EARLY LIFE STAGES OF FOUR CALIFORNIA MARINE SPECIES
Environmental Toxicology and Chemistry, 1990
Continuous-flow toxicity tests using the oil dispersant Corex~t 9527° were performed on the early life stages of four California marine species. Newly released zoospores of the giant kelp, Macrocystispyrifera, embryos of the red abalone, Haliotis rufescens, 4-d-old juveniles of the mysid, Holmes~mysis costata and 10-d-old larvae of the topsmelt, Athermops affinis, were all used in triplicate 48-and 96-h tests. Quantitative verification of dispersant concentrations using UV spectrophotometry was performed twice daily during testing. Results indicated growth of kelp gametophytes was significantly reduced at <2.4 ppm after a 48-h exposure. Of the three animals tested, developing red abalone were the most sensitive (NOEC = 0.63 to 1.50 ppm; LC50 = 1.60 to 2.20 pprn). Mysid juveniles were intermediate in sensitivity (NOEC = 1.66 to 4.20 ppm; LC50 = 4.26 to 7.26 ppm), whereas topsmelt larvae were the least sensitive (NOEC = 12.27 to 14.18 ppm; LC50 = 25.51 to 40.63 ppm). Reproducibility of test data was very high (coefficient of variation = 15.7 to 27.1%).