Contaminant levels in Gulf of Mexico reef fish after the Deepwater Horizon oil spill as measured by a fishermen-led testing program

Emerging Chemical Methods for Petroleum and Petroleum-Derived Dissolved Organic Matter Following the Deepwater Horizon Oil Spill

Despite the fact that oil chemistry and oils spills have been studied for many years, there are still emerging techniques and unknown processes to be explored. The 2010 Deepwater Horizon oil spill in the Gulf of Mexico resulted in a revival of oil spill research across a wide range of fields. These studies provided many new insights, but unanswered questions remain. Over 1,000 journal articles related to the Deepwater Horizon spill are indexed by the Chemical Abstract Service. Numerous ecological, human health, and organismal studies were published. Analytical tools applied to the spill include mass spectrometry, chromatography, and optical spectroscopy. Owing to the large scale of studies, this review focuses on three emerging areas that have been explored but remain underutilized in oil spill characterization: excitation-emission matrix spectroscopy, black carbon analysis, and trace metal analysis using inductively coupled plasma mass spectrometry.

Regional variation in mercury bioaccumulation among NW Atlantic Golden (Lopholatilus chamaeleonticeps) and Blueline (Caulolatilus microps) Tilefish

Mercury (Hg) concentrations in fishes from the NW Atlantic Ocean pose concern due to the importance of this region to U.S. fisheries harvest. In this study, total Hg (THg) concentrations and nitrogen stable isotope (δ¹⁵N) values were quantified in muscle tissues sampled from Golden (Lopholatilus chamaeleonticeps) and Blueline (Caulolatilus microps) Tilefish collected during a fishery-independent survey conducted in the NW Atlantic to compare bioaccumulation patterns between these species. Total Hg concentrations averaged (±SD) 0.4 ± 0.4 μg/g dry weight (d.w.) for L. chamaeleonticeps and 1.1 ± 0.7 μg/g d.w. for C. microps with <2% of all sampled fish, those >70 cm fork length, exceeding the most restrictive USEPA regulatory guidelines for human consumption (THg > 0.46 μg/g w.w.), when converted to wet weight concentrations. The THg concentrations reported here for individuals from the NW Atlantic stock are comparable to those reported for similarly sized individuals collected from the SW Atlantic stock but notably lower than those reported for Gulf of Mexico L. chamaeleonticeps, indicating different Hg exposure and assimilation kinetics for fish from the NW Atlantic, and highlights the broad geographic variability of Hg bioaccumulation among Tilefish stocks. Caulolatilus microps had higher δ¹⁵N values relative to L. chamaeleonticeps and a pattern of decreasing THg concentrations was also present from south to north across the study range. It is concluded that this trophic difference and spatial pattern in Tilefish THg concentrations emphasizes the habitat and resource partitioning mechanisms described for these sympatric species that permits their coexistence in the continental shelf environment. Importantly, regional variability in THg concentrations accentuate the possible roles of fine-scale biotic and abiotic processes that can act to regulate Hg bioaccumulation among individuals and species.

A Review of Epidemiological Studies in Latin American Fishing

Objectives: Maritime health and safety research primarily comes from developed industrial countries, with sparse contributions from developing countries. The aim of this article is to give an overview of the research in Latin American fishery to point out the need for research and prevention in this part of the world.Methods: A systematic search was carried out with Medline/PubMed, Google Scholar, Google Academico, SciELO, Pan American Journal of Public Health, Medicina Maritima, and other relevant Spanish- and English-language journals in Latin America (1984-2018). By using the ICD-10 system we were able to identify the most important studies related to the research questions.Results: A total of 143 scientific articles were identified under the criteria. After duplicates, administrative reports, and conference abstracts were removed, 110 original articles were screened. Of those, 89 peer-reviewed articles on fishermen's health and safety fulfilled the inclusion criteria and were included in the final evaluation. Brazil accounted for the largest share (49), while eight other countries had one to nine studies (and the rest zero). Study objectives included occupational injuries, cancer, divers' disease, skin diseases, hearing loss, ergonomic problems, and environmental pollution. Non-fatal and fatal accident studies in fishing were absent.Conclusion: The lack of occupational injury studies is striking, and it urgently calls for establishing injury registers and monitoring safety in fishing. Among the occupational diseases, pityriasis of the eyes and different types of skin cancer (related ultraviolet radiation exposure) need critical attention and prevention. The scant number of epidemiological studies calls for collaborative international research to establish preventive polices and activities in fishing.

Mercury bioaccumulation in tilefish from the northeastern Gulf of Mexico 2 years after the Deepwater Horizon oil spill: Insights from Hg, C, N and S stable isotopes

Mercury (Hg) concentration in fish of the Gulf of the Mexico (GoM) is a major concern due to the importance of the GoM for U.S. fisheries. The Deepwater Horizon (DWH) oil spill in April 2010 in the northern GoM resulted in large amounts of oil and dispersant released to the water column, which potentially modified Hg bioaccumulation patterns in affected areas. We measured Hg species (methylmercury (MMHg) and inorganic Hg (IHg)) concentrations, and light (C, N and S) and Hg stable isotopes in muscle and liver tissues from tilefish (Lopholatilus chamaleonticeps) sampled in 2012 and 2013 along the shelf break of the northeastern GoM. Fish located close to the mouth of the Mississippi River (MR) and northwest of the DWH well-head (47 km) showed significantly lower Hg levels in muscle and liver than fish located further northeast of the DWH (>109 km), where 98% of tilefish had Hg levels in the muscle above US consumption advisory thresholds (50% for tilefish close to the DWH). Differences in light and Hg stable isotopes signatures were observed between these two areas, showing higher δ¹⁵N, and lower δ²⁰²Hg, Δ¹⁹⁹Hg and δ³⁴S in fish close to the DWH/MR. This suggests that suspended particles from the MR reduces Hg bioavailability at the base of the GoM food chains. This phenomenon can be locally enhanced by the DWH that resulted in increased particles in the water column as evidenced by the marine snow layer in the sediments. On the other hand, freshly deposited Hg associated with organic matter in more oligotrophic marine waters enhanced Hg bioaccumulation in local food webs. Comparing Hg isotopic composition in liver and muscle of fish indicates specific metabolic response in fish having accumulated high levels of MMHg.

Evaluation of New Diagnostic Ratios of Naphthalenes and Fluorenes by Identifying Severely Weathered Oils Collected in Laboratory Simulations and Coastal Weathering Experiments

The composition and physical properties of spilled oil have great changes during the seriously weathering process. It brings great difficulties to the source identification of oil spill. So, the stable and trustworthy diagnostic ratios (DRs) for accurate identification of severely weathered spilled oils are very important. The explosion of Sinopec pipeline happened on November 22, 2013 at Qingdao, China. Local beaches at Jiaozhou Bay were polluted by spilled oils. We have collected original spilled oil samples from an area free from human interference near the oil leakage point after the accident. Synchronized with actual beach weathering, laboratory experiments were conducted to simulate oil weathering for 360 days by using the collected original spilled oil samples. Based on the t test and the repeatability limit method, 65 DRs of naphthalenes and fluorenes were screened. Fifteen DRs, namely, C2Nap/(C2Nap + C3Nap), C2Nap/(C2Nap + C4Nap), C2Nap/total Nap, C3Nap/(C3Nap + C4Nap), C3Nap/total Nap, C4Nap/total Nap, C2Flu/(C2Flu + C3Flu), C2Flu/total Flu, C2Nap/(C2Nap + Flu), C2Nap/(C2Nap + C1Flu), C2Nap/(C2Nap + C2Flu), C2Nap/(C2Nap + C3Flu), C3Nap/(C3Nap + Flu),C3Nap/(C3Nap + C1Flu), total Nap/(total Nap + total Flu), have maintained remarkable stability during the simulated weathering experiments and field weathering process. These stable ratios can retain the characteristics of oil source during weathering. They are very beneficial to improve the accuracy of identifying the source of severely weathered oil and can be used as an effective supplement to existing index system for source identification.

Evaluation of the diagnostic ratios of adamantanes for identifying seriously weathered spilled oils from simulated experiment and actual oil spills

The composition and physical properties of spilled oil have great changes during the seriously weathering process. It brings great difficulties to the source identification of oil spill. So the stable and trustworthy diagnostic ratios (DRs) for accurate identification of severely weathered spilled oils are very important. The explosion of Sinopec pipeline happened on November 22, 2013 at Qingdao, China. Local beaches at Jiaozhou Bay were polluted by spilled oils. We have collected original spilled oil samples from an area free from human interference near the oil leakage point after the accident. Synchronized with actual beach weathering, laboratory experiments were conducted to simulate oil weathering for 360 days by using the collected original spilled oil samples. Based on t test and the repeatability limit method, 50 diagnostic ratios (DRs) of adamantanes were screened. Four DRs, namely 1,3-dimethyladamantane/total dimethyladamantane, 1-methyladamantane/(1-methyladamantane + 1,3-dimethyladamantane), dialkyl diamantane/total diamantane, and diamantane/(diamantane + dialkyl diamantane), have maintained remarkable stability during the simulated weathering experiments and field weathering process. These stable ratios can retain the characteristics of oil source during weathering. They are very beneficial to improve the accuracy of identifying the source of severely weathered oil and can be used as an effective supplement to existing index system for source identification.

Decadal Assessment of Polycyclic Aromatic Hydrocarbons in Mesopelagic Fishes from the Gulf of Mexico Reveals Exposure to Oil-Derived Sources

This study characterizes a decadal assessment of polycyclic aromatic hydrocarbons (PAHs) in the muscle tissues of mesopelagic fish species as indicators of the environmental health of the Gulf of Mexico (GoM) deep-pelagic ecosystem. Mesopelagic fishes were collected prior to the Deepwater Horizon (DWH) oil spill (2007), immediately post-spill (2010), 1 year after the spill (2011), and 5-6 years post-spill (2015-2016) to assess if the mesopelagic ecosystem was exposed to, and retained, PAH compounds from the DWH spill. Results indicated that a 7- to 10-fold increase in PAHs in fish muscle tissues occurred in 2010-2011 (4972 ± 1477 ng/g) compared to 2007 (630 ± 236 ng/g). In 2015-2016, PAH concentrations decreased close to the levels measured in 2007 samples (827 ± 138 ng/g); however, the composition of PAHs still resembles a petrogenic source similar to samples collected in 2010-2011. PAH composition in muscle samples indicated that natural sources (e.g., Mississippi River and natural seeps) or spatial variability within the GoM do not explain the temporal variability of PAHs observed from 2007 to 2016. Furthermore, analysis of different fish tissues indicated the dietary intake and maternal transfer of PAHs as the primary mechanisms for bioaccumulation in 2015-2016, explaining the elevated levels and composition of PAHs in ovarian eggs.

Consumption of Fish and Shrimp from Southeast Louisiana Poses No Unacceptable Lifetime Cancer Risks Attributable to High-Priority Polycyclic Aromatic Hydrocarbons

Following oil spills such as the Deepwater Horizon accident (DWH), contamination of seafood resources and possible increased health risks attributable to consumption of seafood in spill areas are major concerns. In this study, locally harvested finfish and shrimp were collected from research participants in southeast Louisiana and analyzed for polycyclic aromatic hydrocarbons (PAHs). PAHs are some of the most important chemicals of concern regarding oil-spill-contaminated seafood resources during and following oil spills. Some PAHs are considered carcinogens for risk assessment purposes, and currently, seven of these can be combined in lifetime cancer risk assessments using EPA approaches. Most PAHs were not detected in these samples (minimum detection limits ranged from 1.2 to 2.1 PPB) and of those that were detected, they were generally below 10 PPB. The pattern of detected PAHs suggested that the source of these chemicals in these seafood samples was not a result of direct contact with crude oil. Lifetime cancer risks were assessed using conservative assumptions and models in a probabilistic framework for the seven carcinogenic PAHs. Lifetime health risks modeled using this framework did not exceed a 1/10,000 cancer risk threshold. Conservative, health-protective deterministic estimates of the levels of concern for PAH chemical concentration and seafood intake rates were above the concentrations and intake rates modeled under this probabilistic framework. Taken together, consumption of finfish and shrimp harvested from southeast Louisiana following the DWH does not pose unacceptable lifetime cancer risks from these seven carcinogenic PAHs even for the heaviest possible consumers.

Post-Deepwater Horizon Oil Spill Exposure Patterns Among Children in Mobile County, Alabama

OBJECTIVE

The aim of this study was to characterize environmental exposure from Deepwater Horizon oil spill among pre-K to fourth-grade children from six schools in Mobile County, Alabama.

METHODS

A mail-in survey administered 11 months post-oil spill to children's parents/caregivers elicited information on exposure-related activities. Descriptive and multivariable analyses were performed.

RESULTS

Overall, 180 children (coastal schools, 90; inland schools, 90) completed the survey. During the post-oil spill period, children in coastal schools were less likely to reduce their exposure-related activities, including fishing; eating and selling caught fish; visiting beaches; and parental participation in cleanup activities, than children in inland schools. Particularly, fishing and eating caught fish were significantly associated with the coastal group (odds ratio = 2.28; 95% confidence interval = 1.54 to 3.36).

CONCLUSION

Proximity to the shoreline may serve as an indicator for potential exposure in oil spills among vulnerable populations including children.

A three year study of metal levels in skin biopsies of whales in the Gulf of Mexico after the Deepwater Horizon oil crisis

In response to the explosion of the Deepwater Horizon and the massive release of oil that followed, we conducted three annual research voyages to investigate how the oil spill would impact the marine offshore environment. Most investigations into the ecological and toxicological impacts of the Deepwater Horizon Oil crisis have mainly focused on the fate of the oil and dispersants, but few have considered the release of metals into the environment. From studies of previous oil spills, other marine oil industries, and analyses of oil compositions, it is evident that metals are frequently encountered. Several metals have been reported in the MC252 oil from the Deepwater Horizon oil spill, including the nonessential metals aluminum, arsenic, chromium, nickel, and lead; genotoxic metals, such as these are able to damage DNA and can bioaccumulate in organisms resulting in persistent exposure. In the Gulf of Mexico, whales are the apex species; hence we collected skin biopsies from sperm whales (Physeter macrocephalus), short-finned pilot whales (Globicephala macrorhynchus), and Bryde's whales (Balaenoptera edeni). The results from our three-year study of monitoring metal levels in whale skin show (1) genotoxic metals at concentrations higher than global averages previously reported and (2) patterns for MC252-relevant metal concentrations decreasing with time from the oil spill.

Evaluation of diagnostic ratios of phenanthrenes and chrysenes for the identification of severely weathered spilled oils from the simulation weathering and the Sinopec pipeline explosion at Huangdao, 2013

The composition and physical properties of spilled oil undergo great changes during a serious weathering process. This causes great difficulties for identifying the source of an oil spill. So stable and trustworthy diagnostic ratios (DRs) for the accurate identification of severely weathered spilled oils are very important. An explosion in the Sinopec pipeline happened on November 22, 2013 at Qingdao, China. Local beaches at Jiaozhou Bay were polluted by spilled oils. After the accident we collected original spilled oil samples from an area free from human interference near the oil leakage point. Synchronized with actual beach weathering, laboratory experiments were conducted to simulate oil weathering for 360 days by using the collected original spilled oil samples. Based on the t-test and the repeatability limit method, 46 diagnostic ratios (DRs) of phenanthrenes and chrysenes were screened. 18 DRs maintained remarkable stability during the simulated weathering experiments and field weathering process. These stable ratios can retain the characteristics of the oil source during weathering. They are very beneficial for improving the accuracy of identifying the source of severely weathered oil and can be used as an effective supplement to the existing index system for source identification.

The composition and physical properties of spilled oil undergo great changes during a serious weathering process.

Correlations of Biomarkers and Self-Reported Seafood Consumption among Pregnant and Non-Pregnant Women in Southeastern Louisiana after the Gulf Oil Spill: The GROWH Study

Seafood contains health-promoting fatty acids, but is often contaminated with mercury (Hg), complicating recommendations and choices around fish consumption during pregnancy. Self-reported diet may be subject to inaccuracy and this inaccuracy could differ according to pregnancy status. We investigated correlations between self-reported seafood consumption and blood levels of Hg and n-3 polyunsaturated fatty acids (PUFAs) in women affected by the Deepwater Horizon oil spill. Spearman correlation coefficients were calculated comparing log blood Hg and n-3 PUFAs to seafood consumption, then stratified by pregnancy status. Crude and adjusted linear regression models were constructed using biomarkers of Hg and n-3 PUFA and seafood consumption, adjusting for age and pregnancy status. Weak but significant correlations were found between log Hg levels and intake of Hg-containing seafood ( r = 0.15) and were slightly stronger among pregnant women ( r = 0.22, vs. r = 0.10). Biomarkers for n-3 PUFAs were significantly correlated with seafood consumption ( r = 0.12). Hg-containing seafood consumption was associated with increased blood level Hg in the highest quartile in both unadjusted (β = 0.34, 95% CI: 0.15-0.53) and adjusted models (β = 0.28, 95% CI: 0.08-0.48). Self-reported seafood consumption was correlated with biomarkers of both n-3 PUFA and Hg, but this association was different when stratified by pregnancy status. Pregnant women may have better recall of Hg-containing seafood compared to nonpregnant women.

Associations between metal exposure and lesion formation in offshore Gulf of Mexico fishes collected after the Deepwater Horizon oil spill

The objectives of this study were to: (1) examine patterns of short- and long-term metal exposure within the otoliths of six offshore fish species in varying states of health, as indicated by the presence of external skin lesions, and (2) determine if there was a change in otolith metal concentrations concurrent with the Deepwater Horizon (DWH) oil spill. Otoliths collected from 2011 to 2013 in the Gulf of Mexico (GOM) were analyzed for a suite of trace metals known to be associated with DWH oil. We found that lesioned fish often had elevated levels of otolith ⁶⁰Ni and ⁶⁴Zn before, during, and after the DWH oil spill. In addition, metal exposure varied according to species-specific life history patterns. These findings indicate that lesioned individuals were exposed to a persistent source of trace-metals in the GoM prior to the oil spill.

Environmental effects of the Deepwater Horizon oil spill: A review

The Deepwater Horizon oil spill constituted an ecosystem-level injury in the northern Gulf of Mexico. Much oil spread at 1100-1300m depth, contaminating and affecting deepwater habitats. Factors such as oil-biodegradation, ocean currents and response measures (dispersants, burning) reduced coastal oiling. Still, >2100km of shoreline and many coastal habitats were affected. Research demonstrates that oiling caused a wide range of biological effects, although worst-case impact scenarios did not materialize. Biomarkers in individual organisms were more informative about oiling stress than population and community indices. Salt marshes and seabird populations were hard hit, but were also quite resilient to oiling effects. Monitoring demonstrated little contamination of seafood. Certain impacts are still understudied, such as effects on seagrass communities. Concerns of long-term impacts remain for large fish species, deep-sea corals, sea turtles and cetaceans. These species and their habitats should continue to receive attention (monitoring and research) for years to come.