Spatial and temporal impacts of a diesel fuel spill on stream invertebrates

1. We assessed the effects of a 26 500 L diesel fuel spill on the macroinvertebrate fauna of a small trout stream in central New York, U.S.A. To determine the spatial extent of the spill we sampled three locations (0.7, 5.0 and 11.8 km downstream of the spill), each containing a reference site (unaffected tributary) and an impact site (downstream of spill). Sampling was repeated four times over a 15‐month period to assess temporal recovery. 2. Immediately after the spill, invertebrate density at all three locations below the spill was significantly lower than reference density. Three months after the spill, density up to 5 km below the spill was still far lower (<100 individuals per sample) than reference density (800–1200 individuals per sample). A year after the spill, density was similar between reference and impact sites, suggesting that invertebrates had recovered numerically. 3. Taxonomic richness up to 5.0 km below the spill was less than half the reference taxonomic richness and this difference persisted for at least 3 months. Some significant differences between reference and impact sites were observed after 15 months, but these differences could not be attributed to the oil spill. 4. For at least 3 months following the spill, the site immediately downstream of the spill was dominated by Optioservus, a petrochemical‐tolerant riffle beetle. Twelve to 15 months after the spill, both the reference and impact sites near the spill were dominated numerically by the mayfly Ephemerella, but the degree of dominance was twice as large at the impact site. 5. We concluded that the diesel fuel spill significantly reduced the density of invertebrates (by 90%) and taxonomic richness (by 50%) at least 5.0 km downstream, but density recovered within a year. Throughout the study, however, the fauna immediately below the spill was species poor and significantly over‐represented by a single dominant taxon, suggesting that 15 months was not sufficient for full community recovery from the oil spill.     

A Tale of Two Recent Spills—Comparison of 2014 Galveston Bay and 2010 Deepwater Horizon Oil Spill Residues

Managing oil spill residues washing onto sandy beaches is a common worldwide environmental problem. In this study, we have analyzed the first-arrival oil spill residues collected from two Gulf of Mexico (GOM) beach systems following two recent oil spills: the 2014 Galveston Bay (GB) oil spill, and the 2010 Deepwater Horizon (DWH) oil spill. This is the first study to provide field observations and chemical characterization data for the 2014 GB oil spill. Here we compare the physical and chemical characteristics of GB oil spill samples with DWH oil spill samples and present their similarities and differences. Our field observations indicate that both oil spills had similar shoreline deposition patterns; however, their physical and chemical characteristics differed considerably. We highlight these differences, discuss their implications, and interpret GB data in light of lessons learned from previously published DWH oil spill studies. These analyses are further used to assess the long-term fate of GB oil spill residues and their potential environmental impacts.     

Communication Practices for Oil Spills: Stakeholder Engagement During Preparedness and Response

The Deepwater Horizon (DWH) oil spill was a pivotal moment in the expression of and reporting on stakeholder risk perceptions about oil spills, response options, and safety. Public engagement through both traditional and social media was arguably much higher than in prior spills. The DWH response organization undertook a wide variety of activities to manage risks and communicate with both the general public and those directly affected, such as commercial fishers. However, these did not fully address widespread concerns about ecological and human health risks associated with dispersant use. Consequentially the DWH spill heightened awareness of persistent risk communication problems around oil spill response, and especially dispersant use. Oil spill risk research and experience suggests that institutional and operational factors inhibit engaging communities and stakeholders during oil spill preparedness and response, and that such engagement is essential for effective risk management. In this article we review and assess current oil spill preparedness and response practices for community and stakeholder engagement, including related institutional and operational constraints. This assessment suggests five example risk management practices to improve and advance risk communications during oil spill preparedness and response activities.     

POTENTIAL IMPACT OF OIL SPILLS ON CALIFORNIA SEA OTTERS: IMPLICATIONS OF THE EXXON VALDEZ SPILL IN ALASKA

Based on the survival of sea otters held at rehabilitation centers during the 1989 Exxon Valdez oil spill in Alaska, we built two models of otter mortality. One was based on the relationship between mortality and distance from spill origin, the other was based on the relationship between mortality and time from the spill origin. These models are simplistic and are meant as first steps in arriving at realistic risk estimates and in providing a conceptual framework for relating oil spills and sea otter mortality. Using the distance model, we simulated the impact of an Exxon Valdez event occurring at different locations along the California coast. A spill at the Monterey Peninsula had the greatest impact, exposing 90% of the California sea otter population to oil and killing at least 50% of the individuals. The time model was used to predict the mortality of otters exposed to oil of various ages and for various periods of time. It suggested that efforts to rehabilitate otters should be discontinued 20-30 d after a spill. The limitations of the data available from the Exxon Valdez spill emphasize the importance of being prepared to conduct appropriate research during the next oil spill in sea otter habitat.     

Demographic trends of Brown Pelicans in Louisiana before and after the Deepwater Horizon oil spill

Marine oil spills may have extensive and deleterious effects on coastal waterbirds, but pre‐spill data sets are often not available for making comparisons of demographics to the period following a spill. The 2010 Deepwater Horizon oil spill allowed us to compare Brown Pelican (Pelecanus occidentalis) demographics during pre‐ and post‐spill years. We banded 1114 pelicans on Louisiana barrier islands from 2007 to 2009, tracked their distribution via band re‐sighting surveys from 2008 to 2011, and conducted age‐structure surveys. Across Louisiana coastal islands in 2011, we detected 7% of pelicans that had been oiled during the 2010 spill and released following rehabilitation. Similarly, 6% of pelicans (not oiled) banded at the same release site in 2007 were observed across coastal islands 1 yr after banding. We observed variation in proportions of pelicans that were 1, 2, and 3 or more years old among years (2008–2011) and across islands, but little variation could readily be assigned to spill‐related mortality. These Brown Pelican demographic trends one year following the Deepwater Horizon oil spill are contrary to other assessments of the impacts of oil contamination on marine birds. However, additional research is required to evaluate potential long‐term population trends.     

MORTALITY OF SEA OTTERS IN PRINCE WILLIAM SOUND FOLLOWING THE EXXON VALDEZ OIL SPILL

Abstract: This paper presents an estimate of the total number of sea otters that died as a direct consequence of the oil spill that occurred when the T/V Exxon Valdez grounded in Prince William Sound, Alaska on 24 March 1989. We compared sea otter counts conducted from small boats throughout the Sound during the summers of 1984 and 1985 to counts made after the spill during the summer of 1989. We used ratio estimators, corrected for sighting probability, to calculate otter densities and population estimates for portions of the Sound affected by the oil spill. We estimated the otter population in the portion of Prince William Sound affected by the oil was 6,546 at the time of the spill and that the post-spill population in the summer of 1989 was 3,898, yielding a loss estimate of approximately 2,650. Bootstrapping techniques were used to approximate confidence limits on the loss estimate of about 500–5,000 otters. The wide confidence limits are a result of the complex scheme required to estimate losses and limitations of the data. Despite the uncertainty of the loss estimate it is clear that a significant fraction of the otters in the spill zone survived. We observed otters persisting in relatively clean embayments throughout the oil spill zone suggesting that the highly convoluted coastline of Prince William Sound produced refuges that allowed some sea otters in the oil spill area to survive.     

Abundance and Size of Gulf Shrimp in Louisiana's Coastal Estuaries following the Deepwater Horizon Oil Spill

The Deepwater Horizon oil spill impacted Louisiana''s coastal estuaries physically, chemically, and biologically. To better understand the ecological consequences of this oil spill on Louisiana estuaries, we compared the abundance and size of two Gulf shrimp species (Farfantepeneus aztecus and Litopeneus setiferus) in heavily affected and relatively unaffected estuaries, before and after the oil spill. Two datasets were used to conduct this study: data on shrimp abundance and size before the spill were available from Louisiana Department of Wildlife and Fisheries (LDWF). Data on shrimp abundance and size from after the spill were independently collected by the authors and by LDWF. Using a Before-After-Control-Impact with Paired sampling (BACIP) design with monthly samples of two selected basins, we found brown shrimp to become more abundant and the mean size of white shrimp to become smaller. Using a BACIP with data on successive shrimp year-classes of multiple basins, we found both species to become more abundant in basins that were affected by the spill, while mean shrimp size either not change after the spill, or increased in both affected and unaffected basins. We conclude that following the oil spill abundances of both species increased within affected estuaries, whereas mean size may have been unaffected. We propose two factors that may have caused these results: 1) exposure to polycyclic aromatic hydrocarbons (PAHs) may have reduced the growth rate of shrimp, resulting in a delayed movement of shrimp to offshore habitats, and an increase of within-estuary shrimp abundance, and 2) fishing closures established immediately after the spill, may have resulted in decreased fishing effort and an increase in shrimp abundance. This study accentuates the complexities in determining ecological effects of oil spills, and the need of studies on the organismal level to reveal cause-and-effect relationships of such events.     

溢油事故中渔业资源损失的数值模拟评估模式

海洋溢油污染不仅关系到天然渔业资源、海鸟等生物、海域环境、海岸线生态的破坏,而且对渔业、捕捞业、旅游业都会造成巨大损失,甚至会直接或间接地危害人类的健康。短期来看,一方面石油、燃料油等进入海洋后,对海洋生物资源造成影响;另一方面会危害附近海区的海洋环境,侵害海洋生物以及海鸟赖以生存和栖息的环境。长期来看,持续的海洋污染会导致的生态环境失衡,海洋的生产力也随之下降。溢油事故中的渔业资源损失评估作为追究污染事故责任,尽快恢复海域资源与环境的重要一环需要不断改进创新。为了定量确定海洋溢油事故发生后渔业资源的损失程度,将传统的评估模式与现代科学技术相结合,通过海洋动力学、流体力学、海洋生物学、环境化学等多个学科交叉融合,将流场风场模型、溢油模型、海域调查监测、卫星遥感技术、毒性效应和渔业资源的损失评估方法相结合,形成一种渔业资源损失评估的数值模拟评估模式,以完善溢油事故中渔业资源损失评估体系。在溢油事故现场监测数据的基础上,运用数学计算理论选择相对应的溢油模型,结合具体溢油事故案例的潮流数据和风场数据,模拟海上溢油污染的时空分布情况。采用卫星遥感技术根据不同油品在海水中不同的亮度表现,处理得到溢油油膜信息,与模拟得到的油膜信息进行比对验证,并对模型进行修正,通过模拟得出污染海域油浓度分布与溢油污染范围信息,结合溢油污染对不同海洋生物的毒性效应,得到渔业资源的损失程度,为溢油事故的渔业资源损失评估提供一种思路,为溢油事故发生后的损失评估和事故处理起到一定的参考辅助作用。     

Implementation of natural attenuation at a JP-4 jet fuel release after active remediation

After eighteen months of active remediation at a JP-4 jet-fuel spill, aresidual of unremediated hydrocarbon remained. Further site characterizationwas conducted to evaluate the contribution of natural attenuation to controlexposure to hazards associated with the residual contamination in thesubsurface. Activities included the detailed characterization ofground-water flow through the spill; the distribution of fuel contaminantsin groundwater; and the analysis of soluble electron acceptors moving intothe spill from upgradient. These activities allowed a rigorous evaluation ofthe transport of contaminants from the spill to the receptor of groundwater,the Pasquotank River. The transport of dissolved contaminants of concern,that is benzene, toluene, ethyl benzene, xylene isomers (BTEX) andmethyl-tertiary-butyl ether (MTBE), into the river from the source area wascontrolled by equilibrium dissolution from the fuel spill to the adjacentgroundwater, diffusion in groundwater from the spill to permeable layers inthe aquifer, and advective transport in the permeable layers. The estimatedyearly loading of BTEX compounds and MTBE into the receptor was trivial evenwithout considering biological degradation. The biodegradation ofhydrocarbon dissolved in groundwater through aerobic respiration,denitrification, sulfate reduction, and iron reduction was estimated fromchanges in ground-water chemistry along the flow path. The concentrations oftarget components in permanent monitoring wells continue to decline overtime. Long term monitoring will ensure that the plume is under control, andno further active remediation is required.     

生境等价分析在溢油生态损害评估中的应用

生境等价分析是美国国家大气与海洋局在自然资源损害评估中的常用方法之一,但在我国鲜有应用.本文基于生境等价分析的理论研究,结合我国在溢油事故中的评估实践,将该方法改进后,应用于溢油生态损害评估中生境价值的计算.以我国某海域溢油事故的相关数据资料为依据,运用该方法计算修复受损生境的工程规模,并引入生态服务当量因子对各生境进行转化,最终实现了溢油生态损害评估中生境的价值化.     

Effects of pulsed and pressed disturbances on the benthic invertebrate community following a coal spill in a small stream in northeastern USA

In September 1999, a coal-carrying train derailed and spilled 180,000–270,000 kg of coal into the Cayuga Inlet near Ithaca, New York. This study determined the immediate effects of the coal spill and the clean up procedures on the aquatic invertebrate community, and whether the stream recovered from this event after 2 years. Benthic invertebrate samples were taken both upstream and downstream of the coal spill immediately following clean-up efforts and two years later. Just after the coal spill, the total abundance and species richness of aquatic invertebrates were significantly lower downstream of the spill, suggesting that the disturbance caused increased mortality and/or emigration compared to a reference site upstream. Taxa affected most were grazers and turbidity-susceptible invertebrates. Two years later the invertebrate communities were similar upstream and downstream of the spill, except for an increase in the percent of the dominant genus, Hydropsyche(Trichoptera: Hydropsychidae). We speculate that long-term effects of channelization of the stream that occurred during the clean-up prevented the invertebrate assemblage from returning to the conditions observed in a reference site upstream of the coal spill. We propose that large scale environmental clean-ups should be designed to avoid altering ecosystems permanently, and that streams should be allowed to recover naturally without destructive human intervention.     

Fluctuating Asymmetry in Menidia beryllina before and after the 2010 Deepwater Horizon Oil Spill

Assessing the impacts of the Deepwater Horizon oil spill with a dependable baseline comparison can provide reliable insight into environmental stressors on organisms that were potentially affected by the spill. Fluctuating asymmetry (small, non-random deviations from perfect bilateral symmetry) is an informative metric sensitive to contaminants that can be used to assess environmental stress levels. For this study, the well-studied and common Gulf of Mexico estuarine fish, Menidia beryllina, was used with pre and post-oil spill collections. Comparisons of fluctuating asymmetry in three traits (eye diameter, pectoral fin length, and pelvic fin length) were made pre and post-oil spill across two sites (Old Fort Bayou and the Pascagoula River), as well as between years of collection (2011, 2012)-one and two years, respectfully, after the spill in 2010. We hypothesized that fluctuating asymmetry would be higher in post-Deepwater Horizon samples, and that this will be replicated in both study areas along the Mississippi Gulf coast. We also predicted that fluctuating asymmetry would decrease through time after the oil spill as the oil decomposed and/or was removed. Analyses performed on 1135 fish (220 pre and 915 post Deepwater Horizon) showed significantly higher post spill fluctuating asymmetry in the eye but no difference for the pectoral or pelvic fins. There was also higher fluctuating asymmetry in one of the two sites both pre and post-spill, indicating observed asymmetry may be the product of multiple stressors. Fluctuating asymmetry decreased in 2012 compared to 2011. Fluctuating asymmetry is a sensitive measure of sub lethal stress, and the observed variability in this study (pre vs. post-spill or between sites) could be due to a combination of oil, dispersants, or other unknown stressors.     

Investigating a lotic microbial community following a severe detergent spill

A large non-ionic detergent spill affected the Yarqon stream, where water sampling was performed prior to the spill as a part of the stream’s routine sampling and during and after the event. Following the spill, a large foam layer was observed for about 3–4 days accompanied by death of all fauna in the stream. Despite a large quantity of freshwater that was introduced to the stream as an emergency measure, a drastic decrease in dissolved oxygen was also observed. A rapid reduction in bacterial diversity and richness, as measured by automated ribosomal intergenic spacer analysis, was also evident, as microbial assemblages changes accompanied pollutant exposure. However, this analysis showed that the microbial assemblages of the stream were quick to recover and became similar to pre-spill communities as early as a week after the spill. These findings suggest that bacterial assemblages are much more robust to large anthropogenic disturbances than expected.     

Population trends and reproductive success of the European shag Phalacrocorax aristotelis on the Iberian Peninsula following the Prestige oil spill

In 2003, immediately following the Prestige oil spill in Galicia, Spain, we studied the population trends and reproductive performance of European shags (Phalacrocorax aristotelis) at oiled and unoiled colonies. This bird is an important member of the nearshore marine community, breeding in the area affected by the Prestige oil spill. The European shag feeds around the breeding colonies throughout the year, making it a useful indicator of environmental change. Before the oil spill, population trends were similar between oiled and unoiled colonies. Nevertheless, colonies located within the path of the oil suffered greater declines (ca. 10%) compared with pre-spill trends and with population trends at unoiled colonies. In 2003, the breeding success was 50% lower in oiled colonies compared with unoiled colonies. The data available from pre-spill years suggest that the annual reproductive success did not differ among colonies before the impact. European shags breeding at colonies affected by oil showed a negative initial impact from the Prestige oil spill. The reduction in reproductive success at oiled colonies may be due to sub-lethal effects of oil exposure or low food availability after the oil spill.     

Social Media,Public Participation,and the 2010 BP Deepwater Horizon Oil Spill

This research examines how information about an oil spill, its impacts, and the use of dispersants to treat the oil, moved through social media and the surrounding Internet during the 2010 BP Deepwater Horizon oil spill. Using a collection of tweets captured during the spill, we employ a mixed-method approach including an in-depth qualitative analysis to examine the content of Twitter posts, the connections that Twitter users made with each other, and the links between Twitter content and the surrounding Internet. This article offers a range of findings to help practitioners and others understand how social media is used by a variety of different actors during a slow-moving, long-term, environmental disaster. We enumerate some of the most salient themes in the Twitter data, noting that concerns about health impacts were more likely to be communicated in tweets about dispersant use, than in the larger conversation. We describe the accounts and behaviors of highly retweeted Twitter users, noting how locals helped to shape the network and the conversation. Importantly, our results show the online crowd wanting to participate in and contribute to response efforts, a finding with implications for future oil spill response.     

A Comparison of Hydrocarbon Vapor Attenuation in the Field with Predictions from Vapor Diffusion Models

This study used field data from three sites in Southern California to evaluate vapor phase transport from: (1) free product (die-sel and gasoline spill) on groundwater; (2) dissolved benzene (gasoline spill) in groundwater; and (3) hydrocarbon-impacted soil (gasoline spill) in the vadose zone. A sampling program to evaluate the vapor pathway included the following: vertical profile data, minimal purging prior to sample collection, field analysis of data, confirmation of field data using a fixed laboratory analysis, and soil physical property data. Comparison of hydrocarbon vapor concentrations measured in this field study with those calculated using vapor diffusion models suggest that an additional attenuation factor of between 500 and 35,000 is needed to account for observed concentrations. Comparison of hydrocarbon profiles with oxygen, carbon dioxide, and methane values is consistent with the interpretation that biodegradation is primarily responsible for the observed attenuation. Therefore, vapor pathway models that do not account for bioattenuation will result in a large overesti-mation of the risk at spill sites and will not be consistent with field data.     

溢油对南海海洋生态系统的影响及珠江口溢油现状

详细介绍了溢油的化学组成及其进入水体后的变化过程,在此基础上简述了溢油对海洋中的初级生产力、鸟类、贝类和鱼类等生物的影响,以及对红树林和珊瑚礁等重要生态系统的破坏,并说明了溢油对生物和生态系统的破坏机制.统计了近年来在珠江口及其附近海域发生的溢油事件,综述了国内外有关的研究成果并科学阐明了溢油对南海海洋生态系统可能产生的影响,为相关部门研究相应的溢油应急对策及控制方法提供参考.     

What-If Scenario Modeling to Support Oil Spill Preparedness and Response Decision-Making

Scenario analysis (SA) is the process of developing plausible futures around the forces affecting an organization in the face of uncertainties over which it has little control. SA is widely used in the private sector and increasingly a tool of environmental planners grappling with problems of great complexity and uncertainty. SA ideally marries expert judgment with the broader perspectives engaged stakeholders bring. While the 1990 Oil Pollution Act (OPA) brought substantive improvement to oil spill contingency planning, many issues remain. Reguatorily prescribed definitions of ‘worst case’ lead to SA practice that seldom achieves the full promise of the SA approach. Contingency planning overly focused on tactical and operational considerations can leave response managers little prepared to deal with public concerns that emerge in the event of a major spill, concerns increasingly magnified through social media. Politics continues to contribute to poorly conceived contingency planning in which adopted scenarios bear little resemblance to events that subsequently transpire. Risk attenuation and risk amplification both inhibit scenario-based planning around oil spills, evinced by the Deepwater Horizon spill. Improvements in pre-planning in the aftermath of the Exxon Valdez oil spill nevertheless provide a foundation for more effective use of SA.     

DNA damage in eelpout (Zoarces viviparus) from Göteborg harbour

The relationship between DNA damage and the exposure of marine organisms to environmental contaminants was examined in the G?teborg harbour area. This research is part of a wider ecotoxicological study planned to evaluate the biological impact of chemical contamination in the River G?ta estuary, following a bunker oil (10-100 tonnes) spill occurred in June 2003. Here we present data on the DNA strand breaks derived using the comet assay and the presence of apoptotic cells using the diffusion assay in nucleated erythrocytes of the eelpout (Zoarces viviparus) from the study area and at a clean reference site. Polycyclic aromatic hydrocarbon metabolites were also analyzed in the bile of exposed fish. The results showed a high level of damaged DNA, paralleled by a peak in bile PAH metabolites, in fish from the most impacted site, 3 weeks after the oil spill. A significant recovery was observed in specimens from the spill site, 5 months later, but not in fish caught in the middle part of G?teborg harbour, which is chronically subjected to heavy chemical pollution. The levels of apoptic cells did not show any marked variations, but a significant recovery was observed in fish from the oil impacted site 5 months after the spill.