The Toxicity of Oil-Contaminated Sediments During Bioremediation of a Wetland (original) (raw)
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International Oil Spill Conference Proceedings, 2001
A controlled oil spill experiment to determine natural recovery rates and the efficacy of potential remediation strategies in wetland ecosystems was initiated in June 1999 at a site on the St. Lawrence River, Canada dominated by Scirpus pungens. A weathered light crude oil (Mesa) was applied on 16 plots (5 m × 4 m) at the rate of 12 L per plot. Treatment of the plots included: natural attenuation (no treatment), nutrient amendment with granular ammonium nitrate and super triple phosphate, a similar treatment with plants continuously cut back (to evaluate the influence of plant growth on remediation), and a nutrient amendment treatment with sodium nitrate instead of ammonium nitrate. To elucidate the effect of nutrient amendments alone, four unoiled plots were fertilized with ammonium nitrate and triple super phosphate. Sediment samples were routinely recovered for chemical and toxicological analysis over a 21-week period that effectively covered the natural growth season of the plants.
Evaluation of bioremediation strategies of a controlled oil release in a wetland
Marine Pollution Bulletin, 2004
A controlled petroleum release was conducted to evaluate bioremediation in a wetland near Houston, Texas. The 140-day study was conducted using a randomized, complete block design to test three treatments with six replicates per treatment. The three treatment strategies were inorganic nutrients, inorganic nutrients with an alternative electron acceptor, and a no-action oiled control. Samples were analyzed for petroleum chemistry and inorganic nutrients. These results are discussed in the context of our related research involving toxicology and microbiology at the site during the experiment. To evaluate biodegradation, the targeted compounds were normalized to the conservative compound C 30 17a, 21b-[H]hopane, thus reducing the effects of spatial heterogeneity and physical transport. The two biostimulation treatments demonstrated statistically-higher rates of biodegradation than the oiled no-action control. For the majority of the experiment, target nutrient levels were maintained. Further research may be warranted to optimize these bioremediation strategies as well as evaluating additional treatment strategies for wetlands and other shoreline systems.
Toxicity assessment of oil-contaminated freshwater sediments
Environmental Toxicology, 2004
The performance of four microscale toxicity bioassays conducted on whole sediments was evaluated during a bioremediation project undertaken in 1999–2000 on a crude oil–contaminated freshwater shoreline of the St. Lawrence River, Quebec, Canada. The toxicity tests assessed included: (1) the Microtox® solid-phase assay (MSPT), (2) the Biotox™ Flash solid-phase test (Flash), (3) the algal solid-phase assay (ASPA), and 4) the Ostracodtoxkit solid-phase assay. Data generated with these assays were compared with those obtained using the standard endobenthic amphipod (Hyalella azteca) bioassay. Bioanalytical comparisons indicated that all five solid-phase tests were useful in detecting the toxicity of oiled sediments; however, statistical analyses distinguished a difference in response between the invertebrate (amphipod and Ostracodtoxkit) and bacterial luminescence tests (MSPT and Flash). Based on these results, it is recommended that careful selection of biotests be made in the design of the test battery for assessment of residual oil sediment toxicity. Time-series toxicity data generated with ASPA indicated that oiled sediments in the freshwater wetlands of the St. Lawrence River remained toxic to phytoplankton for at least 65 weeks and that remediation treatment was able to accelerate detoxification by 16 weeks. © 2004 Wiley Periodicals, Inc. Environ Toxicol 19: 267–273, 2004.
Proceedings, 1995
Although bioremediation for oil spill cleanup has received considerable attention in recent years, its satisfactory use in the cleanup of oil spills in the wetland environment is still questionable and generally untested. We have initiated a multidisciplinary experimental program to evaluate the use of both microbial seeding and fertilizer as means of enhancing oil biodégradation in coastal salt marshes. We are utilizing controlled greenhouse experiments as well as field trials to test the efficacy and ecological safety of these enhanced biodégradation methodologies. This paper summarizes the overall scope of the study and presents some preliminary findings concerning marsh plant response to the bioremediation agents. We shall report on the results of the first year of this three-year investigation. Sods of marsh (soil and vegetation intact), approximately 30 cm in diameter and 25 cm deep, collected from the inland zone of a Spartina alterniflora dominated salt marsh in south Louisiana were used in a greenhouse experiment to identify the effects on plant and soil responses of the following treatments, with and without oil: seeding product, fertilizer product, and control (no product). Mesocosms were sampled for petroleum hydrocarbon chemistry to identify and quantify the degree of oil biodégradation, soil microbial response to determine the effect of the bioremediation products on the microbial communities that are performing the oil biodégradation, soil chemistry to determine the effect of the bioremediation products (such as nutrients, soil reducing conditions, and soil toxins) on those factors that limit the growth of microbes and plants, and plant response to evaluate the effects of the oil and products on plant vigor and growth. This paper presents selected plant responses that demonstrated that the bioremediation products tested had no adverse impact on plant growth. Additionally, soil respiration was increased by fertilizer, but not microbial, application.
International Oil Spill Conference Proceedings, 2001
Biostimulation has been shown to be an effective tool for the treatment of oil spills in medium to low-energy marine environments. Little information is available on the bioremediation of oil spills in low-energy coastal wetlands. Most of the previous laboratory studies have been carried out under total flooding conditions. In this study, a tidal salt marsh was simulated in laboratory microcosms. The study was carried out in glass columns filled to a depth of 10 cm with sediment. Each microcosm was operated on a 24 hours square tidal cycle with a 12-hour submergence period. The entire sediment was mixed with weathered fuel oil No 2 (F02) to a concentration of 20 g/kg of wet sediment. Two biomarkers, 5α-cholestane and heptamethylnonane were added to the oil for data normalization. Nutrients were premixed with the soil in an amount equivalent to 1 gram as nitrogen and 0.2 grams as phosphorus per column. The experiment was conducted with a no fertilizer control and three types of ferti...
Intrinsic bioremediation of a petroleum-impacted wetland
Marine Pollution Bulletin, 2003
Following the 1994 San Jacinto River flood and oil spill in southeast Texas, a petroleum-contaminated wetland was reserved for a long-term research program to evaluate bioremediation as a viable spill response tool. The first phase of this program, presented in this paper, evaluated the intrinsic biodegradation of petroleum in the contaminated wetland. Sediment samples from six test plots were collected 11 times over an 11-month period to assess the temporal and spatial petroleum concentrations. Petroleum concentrations were evaluated using gas chromatography-mass spectrometer analyses of specific target compounds normalized to the conservative biological marker, C 30 17a,21b(H)-hopane. The analyses of specific target compounds were able to characterize that significant petroleum biodegradation had occurred at the site over the one-year period. Total resolved saturate and total resolved aromatic hydrocarbon data indicated the petroleum was degraded more than 95%. In addition, first-order biodegradation rate constants were calculated for the hopane-normalized target compounds and supported expected biodegradation patterns. The rapid degradation rates of the petroleum hydrocarbons are attributed to conditions favorable to biodegradation. Elevated nutrient levels from the flood deposition and the unconsolidated nature of the freshly deposited sediment possibly provided a nutrient rich, oxic environment. Additionally, it is suggested that an active and capable microbial community was present due to prior exposure to petroleum. These factors provided an environment conducive for the rapid bioremediation of the petroleum in the contaminated wetland.
Ecological Engineering, 1998
The combined effects of biostimulation and phytoremediation as a means of post-oil spill habitat restoration and enhancement of oil degradation in the soil were evaluated. Marsh sods of Spartina alterniflora and Spartina patens were dosed with 0, 4, 8, 16 and 24 l m − 2 of south Louisiana crude oil in the greenhouse. Plants were killed at oil dosages of 8 l m − 2 in the growing season following oil application. Two years after application of the oil, S. alterniflora and S. patens individuals were transplanted into the oiled and unoiled sods. Fertilizer was applied 1 and 7 months after transplantation. Application of the fertilizer significantly increased biomass of the transplants within 6 months and regrowth biomass of the transplants 1 year after transplantation for both plant species. The residual oil in the soil did not significantly affect the biomass of the S. patens transplants compared with that in the no oil treatment, except at the highest oil level. However, regrowth biomass of the S. alterniflora transplants treated with fertilizer was significantly higher at all oil levels up to 250 mg g − 1 than in the unoiled treatment, with or without fertilizer. The oil degradation rate in the soil was significantly enhanced by the application of fertilizer in conjunction with the presence of transplants. These results suggest that vegetative transplantation, when implemented with fertilization, can simultaneously restore oil contaminated wetlands and accelerate oil degradation in the soil.
Sustainability
This study evaluated the efficacy of using Tween 80 surfactant (TW80) and food-waste anaerobic digestate fibre (FWAD) as soil amendments for the remediation of wetlands contaminated by crude oil. A 112-day mesocosms experiment was carried out to simulate hydrocarbon degradation under typical acidified wetland conditions. Soil was spiked with 50,000 mg kg−1 crude oil and TW80 and FWAD were added to mesocosms at 10%, 20% and 30% w/w. The soil basal respiration, microbial community dynamics, environmental stress, alkanes, and PAHs degradation were monitored throughout the mesocosm experiment. Amending the mesocosms with FWAD and TW80 enabled the recovery of the soil microbial activities. This was evidenced by soil basal respiration which was the highest in the 30% FWAD and 30% TW80 mesocosms and translated into increased degradation rate of 32% and 23% for alkanes, and 33% and 26% for PAHs compared to natural attenuation, respectively. Efficient total hydrocarbon degradation was achiev...
Effect of biostimulation treatments on the toxicity of oil-contaminated mangrove sediment
Ecotoxicology and Environmental Contamination, 2018
Bioassays with the marine copepod Tisbe biminiensis were used to evaluate the efficiency of three bioremediation treatments on oil contaminated sediments. Two biostimulation treatments (adding NPK and OSMOCOTE fertilizers) and a natural attenuation treatment (experimental control, without fertilizers) were evaluated. The addition of NPK fertilizer had a strong lethal effect on T. biminiensis females probably associated to ammonium compounds, but this effect disappeared after 15 days. The OSMOCOTE releases nutrients in a gradual manner and as such, had no lethal effect on T. biminiensis females. In the natural attenuation treatment, the fecundity of T. biminiensis increased 200% and this indicates that natural attenuation treatment effectively attenuated the sub-lethal toxicity. Biostimulation treatments were not more efficient in obtaining lower toxicity levels of oil contaminated sediment compared to natural attenuation as the recovery of the endpoint affected by contamination (fecundity) increased at the same rate in the 3 treatments over time. In conclusion, adding fertilizers with high ammonium compound concentrations and rapid release is not recommended as a bioremediation treatment in mangroves.