Influence of dispersant application on the toxicity to sea urchin embryos of crude and bunker oils representative of prospective oil spill threats in Arctic and Sub-Arctic seas (original) (raw)
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Archives of Environmental Contamination and Toxicology, 1998
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Water, Air, and Soil Pollution, 2006
An evaluation of the toxicity of seawater and sand sampled from an area of the Galician coast (NW Iberian Peninsula), highly impacted by the Prestige fuel-oil spill, was attempted by using marine invertebrate embryogenesis bioassays with bivalves and sea urchins. Water samples were frozen and toxicity testing was delayed until the reproductive season of the sea urchins. Sand samples were elutriated and tested within 13 d from sampling, using bivalves from commercial stocks. Sand elutriates were non toxic for embryos despite visual presence of small tar balls. In contrast, seawater from the most impacted site was highly toxic during the first days after the spill, with complete inhibition of embryogenesis even after 4-fold dilution. In a lower degree toxicity persisted for two months in light-exposed coastal water. These findings stress the impact to water column organisms of the less conspicuous and frequently overlooked water-accommodated fraction, rather than the more visible oil slick.
Predicting the Aquatic Toxicity of Crude Oils
International Oil Spill Conference Proceedings, 2001
Aquatic toxicity information is critical to provide scientifically defensible estimates of ecological impact and natural resource injury to aquatic organisms resulting from a petroleum spill. For most crude oils, the availability of aquatic toxicity information is a significant data gap. As part of Chevron's oil-specific properties summary sheet project, a series of marine fish (silversides, top smelt) and invertebrate (mysid shrimp) acute toxicity tests on five crude oils with extensive chemical analysis (e.g., VPH C6–C9, CROSERF VOCs, EPH C10–C32, PAHs) of exposure concentrations have been performed. Acute toxicity studies were conducted under standard test guidelines. ASTM D 6081 procedures were used to prepare individual water extracts, also called water-accommodated fractions (WAFs), of each test concentration to which the test organisms were exposed. WAF preparation and testing was done in tightly closed containers with minimal headspace to reduce volatilization and mainta...
Environmental Toxicology and Chemistry, 2013
The acute toxicity of physically and chemically dispersed crude oil and the dispersant Corexit 9500 were evaluated for key Arctic species. The copepod Calanus glacialis, juvenile Arctic cod (Boreogadus saida), and larval sculpin (Myoxocephalus sp.) were tested under conditions representative of the Beaufort and Chukchi Seas during the ice-free season. The toxicity of 3 water-accommodated fractions (WAF) of Alaska North Slope crude oil was examined with spiked, declining exposures. A dispersant-only test was conducted with the copepod C. glacialis. Each preparation with oil (WAF, breaking wave WAF [BWWAF], and chemically enhanced WAF [CEWAF]) produced distinct suites of hydrocarbon constituents; the total concentrations of oil were lowest in WAF and highest in CEWAF preparations. The relative sensitivity for the different species and age classes was similar within each WAF type. Median lethal concentration values based on total petroleum hydrocarbons ranged from 1.6 mg/L to 4.0 mg/L for WAF and BWWAF treatments and from 22 mg/L to 62 mg/L for CEWAF. For Corexit 9500 exposures, median lethal concentration values ranged from 17 mg/L to 50 mg/L. The differences in the relative toxicity among the accommodated fractions indicated that the majority of petroleum hydrocarbons in the CEWAF are in less acutely toxic forms than the components that dominate the WAF or BWWAF. Further evaluation showed that the parent polycyclic aromatic hydrocarbon compounds, specifically naphthalene, were highly correlated to acute toxicity.
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