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

Traces of oil in sea turtle feces

In 2019, an oil spill hit the Brazilian Northeast coast causing impact to several ecosystems, including sea turtles' breeding and feeding areas. This study aimed to investigate whether sea turtles were impacted by this oil disaster, correlating the oil found inside feces with a sandy-oiled sample collected on the beach some days after the accident. The fecal samples were collected in the upper mid-littoral reef areas during three consecutive days in February 2020. The results suggested that sea turtles consumed algae contaminated by petroleum. Hydrocarbons composition of oil inside feces was similar to the sandy-oiled sample, suggesting they were the same. Lighter aliphatic and polycyclic aromatic compounds were missing, indicating both sandy-oiled and oil inside the feces had experienced significant evaporation prior to collection. Although the long-term damage is still unknown, the data are novel and relevant to support future research and alert authorities about the risks to sea turtles.

Polycyclic aromatic hydrocarbon (PAH) source identification and a maternal transfer case study in threatened killer whales (Orcinus orca) of British Columbia, Canada

The northeastern Pacific (NEP) Ocean spans the coast of British Columbia (Canada) and is impacted by anthropogenic activities including oil pipeline developments, maritime fossil fuel tanker traffic, industrial chemical effluents, agricultural and urban emissions in tandem with stormwater and wastewater discharges, and forest wildfires. Such events may expose surrounding marine environments to toxic polycyclic aromatic hydrocarbons (PAHs) and impact critical habitats of threatened killer whales (Orcinus orca). We analyzed skeletal muscle and liver samples from stranded Bigg's killer whales and endangered Southern Resident killer whales (SRKWs) for PAH contamination using LRMS. C3-phenanthrenes/anthracenes (mean: 632 ng/g lw), C4-dibenzothiophenes (mean: 334 ng/g lw), and C4-phenanthrenes/anthracenes (mean: 248 ng/g lw) presented the highest concentrations across all tissue samples. Diagnostic ratios indicated petrogenic-sourced contamination for SRKWs and pyrogenic-sourced burdens for Bigg's killer whales; differences between ecotypes may be attributed to habitat range, prey selection, and metabolism. A mother-fetus skeletal muscle pair provided evidence of PAH maternal transfer; low molecular weight compounds C3-fluorenes, dibenzothiophene, and naphthalene showed efficient and preferential exposure to the fetus. This indicates in-utero exposure of PAH-contamination to the fetus. Our results show that hydrocarbon-related anthropogenic activities are negatively impacting these top predators; preliminary data found here can be used to improve oil spill and other PAH pollution management and regulation efforts, and inform policy to conserve killer whale habitats in the NEP.

Synergistic and additive effects of microplastic, nickel and pyrene on survival, reproduction, and egestion of a tropical copepod

Coastal tropical ecosystems provide livelihood for millions of people but are at the same time exposed to an increasing intensity of diverse anthropogenic stressors, including pollution. Nevertheless, the combined effects of pollutants on marine ecosystems are poorly understood, particularly regarding lower trophic levels (plankton) and tropical ocean. We exposed the tropical copepod Centropages velificatus to 4-5 concentrations of a heavy metal (nickel), an oil compound (pyrene) and microplastic (PET), either alone or in combination, and measured their egestion, reproduction, and mortality rates. Microplastic alone did not have any effect on pellet or egg production of copepods, whereas nickel reduced egg production rate at concentrations ≥1 µg L-1 and pyrene reduced both egg and pellet production rates at concentrations ≥1 nM. The addition of nickel and pyrene to PET - microplastic resulted in a reduction similar to one caused by nickel or pyrene alone, suggesting an additive effect. In contrast, a combination of nickel and pyrene had a synergistic effect, with a strong reduction in survival, egg and pellet production. Our results suggest that combinations of contaminants that are commonly found in tropical coastal waters have detrimental effects on copepods-the crucial link in the pelagic food web-at lower concentrations than suggested by single stressor studies. This can have an influence on the food web productivity - the basis of fisheries that local communities rely on.

The deep dive of organohalogen compounds: Bioaccumulation in the top predators of mesopelagic trophic webs, pygmy and dwarf sperm whales, from the Southwestern Atlantic ocean

Kogia sima and Kogia breviceps are apex predators of mesopelagic trophic webs being far from most anthropogenic threats. However, chemical pollutants and naturally synthesized compounds may travel long distances. This study aimed to use kogiid whales as sentinels of mesopelagic trophic webs in the Southwestern Atlantic Ocean. Persistent organic pollutants (POPs), e.g., polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT) and metabolites, mirex, hexachlorobenzene (HCB), polybrominated diphenylethers (PBDEs), pentabromoethylbenzene (PBEB) and hexabromobenzene (HBB), and the naturally produced methoxylated BDE (MeO-BDEs) were determined in the blubber of 16 K. sima and 15 K. breviceps. Among the organochlorine compounds, DDTs were the main group found in K. sima and in K. breviceps (1636.6 and 3983.3 ng g-1 lw, respective medians), followed by PCBs (425.9 and 956.1 ng g-1 lw, respectively), mirex (184.1 and 375.6 ng g-1 lw, respectively), and HCB (132.4 and 340.3 ng g-1 lw, respectively). As for the organobromine, the natural MeO-BDEs were predominant (1676.7 and 501.6 ng g-1 lw, respectively), followed by PBDEs (13.6 and 10.3 ng g-1 lw, respectively) and PBEB (2.2 and 2.9 ng g-1 lw, respectively). In general, POPs concentration was higher in K. breviceps than in K. sima. Conversely, MeO-BDEs concentration was higher in K. sima than in K. breviceps. Differences in concentrations in these sympatric odontocetes were attributed to distinct species, sampling sites, and biological parameters and suggest some level of niche segregation. It is noteworthy the long-range reach and bioaccumulation of these synthetic compounds in an unexplored habitat, that present an increasing economic interest.

Insights into mechanism of DNA damage and repair-apoptosis in digestive gland of female scallop Chlamys farreri under benzo[a]pyrene exposure during reproductive stage

As one of the most carcinogenic persistent organic pollutants (POPs), benzo[a]pyrene (B [a]P) brings high toxicity to marine bivalves. Digestive gland is the most important metabolism-related organ of aquatic animals. This study conducted the digestive gland transcriptome of Chlamys farreri under B[a]P treatment at reproductive stages. And the reproductive-stage dependence metabolism-DNA repair-apoptosis process of scallops under 0, 0.04, 0.4 and 4 μg/L B[a]P was studied by qRT-PCR. The results demonstrated that the detoxification metabolism was disturbed after ovulation except for CYP3A4. In antioxidant system, antioxidant enzyme CAT and GPX, and GGT1 (one of the non-enzymatic antioxidants synthesis gene) continuously served the function of antioxidant defense. Three types of DNA repair were activated under B[a]P stress, however, DNA strand breaks were still serious. B[a]P exposure weakened death receptor pathway as well as enhanced mitochondrial pathway, surprisingly suppressing apoptosis in scallops. In addition, ten indicators were screened by Spearman correlation analysis. This study will provide sound theoretical basis for bivalve toxicology and contribute to the biomonitoring of marine POPs pollution.

A critical review on the removal of toxic pollutants from contaminated water using magnetic hybrids

The persistence of organic/inorganic pollutants in the water has become a serious environmental issue. Among the different pollutants, dyes and heavy metal pollution in waterways are viewed as a global ecological problem that can have an impact on humans, plants, and animals. The necessity to develop a sustainable and environmentally acceptable approach to remove these toxic contaminants from the ecosystem has been raised. In the past two decades, rapid industrialization and anthropogenic activities in developed countries have aggravated environmental pollution. Industrial effluents that are discharged directly into the natural environment taint the water, which has a consequence for the water resources. Magnetic nanohybrids are broadly investigated materials used in the adsorption and photocatalytic degradation of poisonous pollutants present across water effluents. In the present review, the toxic health effects of heavy metals and dyes from the water environment have been discussed. This paper reviews the role of magnetic nanohybrids in the removal of pollutants from the water environment, providing an adequate point of view on their new advances regarding their qualities, connection methodologies, execution, and their scale-up difficulties.

Hydrocarbons in size-fractionated plankton of the Mediterranean Sea (MERITE-HIPPOCAMPE campaign)

Aliphatic and polycyclic aromatic hydrocarbons (AHs and PAHs, respectively) were analyzed in the dissolved fraction (<0.7 μm) of surface water and in various particulate/planktonic size fractions (0.7-60, 60-200, 200-500 and 500-1000 μm) collected at the deep chlorophyll maximum, along a North-South transect in the Mediterranean Sea in spring 2019 (MERITE-HIPPOCAMPE campaign). Suspended particulate matter, biomass, total chlorophyll a, particulate organic carbon, C and N isotopic ratios, and lipid biomarkers were also determined to help characterizing the size-fractionated plankton and highlight the potential link with the content in AHs and PAHs in these size fractions. Ʃ28AH concentrations ranged 18-489 ng L-1 for water, 3.9-72 μg g-1 dry weight (dw) for the size fraction 0.7-60 μm, and 3.4-55 μg g-1 dw for the fractions 60-200, 200-500 and 500-1000 μm. AH molecular profiles revealed that they were mainly of biogenic origin. Ʃ14PAH concentrations were 0.9-16 ng L-1 for water, and Ʃ27PAH concentrations were 53-220 ng g-1 dw for the fraction 0.7-60 μm and 35-255 ng g-1 dw for the three higher fractions, phenanthrene being the most abundant compound in planktonic compartment. Two processes were evidenced concerning the PAH patterns, the bioreduction, i.e., the decrease in concentrations from the small size fractions (0.7-60 and 60-200 μm) to the higher ones (200-500 μm and 500-1000 μm), and the biodilution, i.e., the decrease in concentrations in plankton at higher suspended matter or biomass, especially for the 0.7-60 and 60-200-μm size fractions. We estimated the biological pump fluxes of Ʃ27PAHs below 100-m depth in the Western Mediterranean Sea at 15 ± 10 ng m-2 day-1, which is comparable to those previously reported in the South Pacific and Indian Ocean.

Zooplankton biomass, size structure, and associated metabolic fluxes with focus on its roles at the chlorophyll maximum layer during the plankton-contaminant MERITE-HIPPOCAMPE cruise

Recent studies have demonstrated that plankton can be a key pathway for the uptake and transfer of contaminants entering the marine environment up to top predators. The plankton-contaminant MERITE-HIPPOCAMPE cruise was devoted to quantifying contaminants in water and the whole plankton size range (10 size fractions) at 10 stations along a north-south transect in the western Mediterranean Sea from the French to the Tunisian coasts through the Provençal and Algerian basins. Pumping and filtering devices and net sampling have been used for collecting very high amounts of small particles and planktonic organisms in the chlorophyll maximum layer (CML). The present paper characterizes the zooplankton components for which the contaminant measurements were carried out. At each station, a horizontal towed Hydro-Bios net with a 60 μm mesh-size net was used to discriminate 5 size-fractions from 60 μm to a few mm. For each size-fraction, one part of the sample was used for dry weight measurements and the other one for estimating the contribution to biomass of detritus, phytoplankton, and among zooplankton of the major taxonomic groups based on the imagery tools ZOOSCAN and FLOWCAM. In each zooplankton size fraction, metabolic rates were calculated from the size spectrum to estimate trophic and excretion fluxes flowing through this fraction. These observations were compared to a similar analysis of tows in the upper layer (vertical) and the surface layer (horizontal). The total sampled biomass concentration at the CML was higher than in the water column (COL) and much higher than at the surface (SURF) in most of the stations, but in the CML and COL a substantial contribution was due to detritus mostly concentrated in the smallest size-fractions (60-200 μm and 200-500 μm). Absolute values of zooplankton biomass show neither a clear spatial pattern nor a significant difference between strata. The CML layer was dominated by copepods similarly to COL and SURF, but presented a higher contribution of nauplii and a near absence of appendicularians. At some stations, crustaceans and gelatinous plankton could be important contributors to CML. The zooplankton biomass composition of the two smallest fractions (<500 μm) was dominated by nauplii, small copepods and, occasionally, by small miscellaneous organisms (mostly pteropodes). In contrast, clear differences between stations appeared for the largest fractions (>500 μm) due to large crustaceans, gelatinous organisms, and chaetognaths. These changes in biomass composition according to size fractions suggest a progressive trophic shift from dominant herbivory in the smallest fractions to more contrasted trophic structure (including carnivory) in the largest fractions. The daily carbon demand and the N and P excretion of zooplankton were on average higher at the CML but with no significant difference with COL. The zooplankton grazing represented 2.7 to 22.7 % of the phytoplankton stock per day, whereas its excretion represented a daily N and P recycling compared to dissolved inorganic nitrogen and phosphorus stocks ranging respectively from 0.2 to 19 % and from 0 to 21 %. This information should help in the interpretation of the content of various contaminants in zooplankton fractions.

Concentration of polycyclic aromatic hydrocarbons (PAHs) and histological changes in Anomalocardia brasiliana and Crassostrea rhizophorae from Pernambuco, Brazil after the 2019 oil spill

The present study aimed to analyze the concentrations of polycyclic aromatic hydrocarbons (PAHs) in populations of the shellfish Anomalocardia brasiliana and oysters Crassostrea rhizophorae three years after the 2019 oil spill, as well as evaluate histopathological changes on the gill tissues of the bivalves. Individuals of both species were sampled at points along the northern and southern coast of Pernambuco, Brazil. The permanence of oil residues was confirmed, evidenced by the total concentration of PAHs in the shellfish from the northern coast, which was roughly four times higher than the southern one. Among the PAHs analyzed, the low molecular weight compounds naphthalene and anthracene were the main contributors to the total concentration. Histological changes in the gills of the bivalves, were more severe in the specimens sampled on the north coast indicating alterations in the bivalve's health, mainly on the state's northern coast.

Pressurized Liquid Extraction: A Powerful Tool to Implement Extraction and Purification of Food Contaminants

Pressurized liquid extraction (PLE) is considered an advanced extraction technique developed in the mid-1990s with the aim of saving time and reducing solvent with respect to traditional extraction processes. It is commonly used with solid and semi-solid samples and employs solvent extraction at elevated temperatures and pressures, always below the respective critical points, to maintain the solvent in a liquid state throughout the extraction procedure. The use of these particular pressure and temperature conditions changes the physicochemical properties of the extraction solvent, allowing easier and deeper penetration into the matrix to be extracted. Furthermore, the possibility to combine the extraction and clean-up steps by including a layer of an adsorbent retaining interfering compounds directly in the PLE extraction cells makes this technique extremely versatile and selective. After providing a background on the PLE technique and parameters to be optimized, the present review focuses on recent applications (published in the past 10 years) in the field of food contaminants. In particular, applications related to the extraction of environmental and processing contaminants, pesticides, residues of veterinary drugs, mycotoxins, parabens, ethyl carbamate, and fatty acid esters of 3-monochloro-1,2-propanediol and 2-monochloro-1,3-propanediol from different food matrices were considered.

Spatiotemporal patterns in the prevalence of microscopic hepatic changes in Gulf of Mexico Tilefish (Lopholatilus chamaeleonticeps) and associations with hepatic PAHs

Following the 2010 Deepwater Horizon blowout, demersal longline surveys were conducted across the Gulf of Mexico (GoM) continental shelf to evaluate polycyclic aromatic hydrocarbon (PAH) exposure, tissue accumulation, and health indices in demersal fishes. Tilefish (Lopholatilus chamaeleonticeps), a target species due to Gulf-wide distribution with documented high exposure to PAHs, were collected in the north central GoM at repeat stations 2012 to 2015, and from the northwest GoM, Bay of Campeche, and Yucatán Shelf in 2015 and 2016. Liver samples (n = 239) were analyzed for microscopic hepatic changes (MHCs) by a board-certified veterinary pathologist. Histological analyzes identified 14 MHCs. Prevalence of MHCs was generally uniform throughout the GoM, except for low prevalence on the Yucatán Shelf. Inflammatory and vacuolar changes were most prevalent, while pre-neoplasia and neoplasia were rare. Tilefish sampled annually in the north central GoM showed increases in inflammatory MHCs and glycogen-type vacuolar change over time, while lipid-type vacuolar change decreased over time. Short-term exposure to PAHs was assessed by measuring PAH metabolites in bile (n = 100) using high performance liquid chromatography with fluorescence detection. Longer-term accumulation of PAHs in tissue was assessed by analyzing liver (n = 111) for PAHs and alkylated homologs using QuEChERS extractions and gas chromatography tandem mass spectrometry. Six MHCs including glycogen-type vacuolar change, biliary fibrosis, foci of cellular alteration, parasites, hepatocellular atrophy, and necrosis were significantly associated with hepatic PAH accumulation in Tilefish from the northern central GoM; however, no MHCs were associated with biliary PAH metabolites. Combined with previous studies of PAH exposure and health indices in north central GoM Tilefish post-Deepwater Horizon, which also identified decreases in hepatic lipid storage and Fulton's condition factor that were correlated to increasing PAH exposure, these data indicate concerning temporal trends and changes in hepatic energy storage.

Analysis of polycyclic aromatic hydrocarbons (PAHs) in surface sediments and edible aquatic species in an oil-contaminated mangrove ecosystem in Bodo, Niger Delta, Nigeria: Bioaccumulation and human health risk assessment

This work investigated the occurrence and risks associated with polycyclic aromatic hydrocarbons (PAHs) in tissues from five commonly consumed aquatic species (swimming crabs, estuarine shrimp, tiger prawns, periwinkles, and tilapia) and sediment across six sites in the area around Bodo town, in the Niger Delta region of Nigeria. We aimed to establish a relationship between PAH concentrations in sediment and biota, and to derive biota-sediment accumulation factors (BSAFs). Risks to human health associated with consumption of impacted food sources were assessed based on measured biotic concentrations of PAHs. The average concentration of PAHs and the number of PAHs measured above the limit of quantification varied greatly between different biota, with the lowest average concentrations observed in tilapia, followed by tiger prawns, crabs, estuarine shrimp, and the highest concentrations were observed in periwinkles. Similar to biotic concentrations, BSAFs were found to vary greatly across species, sites, and PAHs, though BSAFs for all organisms except periwinkles were below a value of 1. In periwinkles, BSAFs exceeded a value of 1 for phenanthrene (BSAF = 1.7), pyrene (1.5) and benzo[k]fluoranthene (1.7). Risks to human health associated with consumption of these species were assessed using the BaP toxic-equivalent approach for cancer risks and the toxic unit approach which jointly considered carcinogenic but also non-cancer hazards. The BaP toxic-equivalent approach showed that the excess lifetime cancer risk resulting from daily consumption of 0.2 kg of seafood ranged between 1.3 × 10^-6 for tiger prawn and tilapia to 4.1 × 10^-6 for periwinkles, which is below the excess lifetime cancer risk of 10^-4 used by Dutch and Nigerian authorities for sediment intervention values. This finding is supported by the results obtained from the toxic unit approach which indicates that the ratios of the estimated dose and the maximal permissible risk level for summed PAHs never exceeded 1.

A comprehensive petrochemical vulnerability index for marine fishes in the Gulf of Mexico

Oil and gas extraction activities occur across the globe, yet species-specific toxicological information on the biological and ecological impacts of exposure to petrochemicals is lacking for the vast majority of marine species. To help prioritize species for recovery, mitigation, and conservation in light of significant toxicological data gaps, a trait-based petrochemical vulnerability index was developed and applied to the more than 1700 marine fishes present across the entire Gulf of Mexico, including all known bony fishes, sharks, rays and chimaeras. Using life history and other traits related to likelihood of exposure, physiological sensitivity to exposure, and population resiliency, final calculated petrochemical vulnerability scores can be used to provide information on the relative sensitivity, or resilience, of marine fish populations across the Gulf of Mexico to oil and gas activities. Based on current knowledge of traits, marine fishes with the highest vulnerability scores primarily occur in areas of high petrochemical activity, are found at or near the surface, and have low reproductive turnover rates and/or highly specialized diet and habitat requirements. Relative population vulnerability scores for marine fishes can be improved with additional toxicokinetic studies, including those that account for the synergistic or additive effect of multiple stressors, as well as increased research on ecological and life history traits, especially for deep living species.

High inter-species variability in elemental composition of the twilight zone fauna varies implications for predators and exploitation by humans

While the importance of oceanic micronektonic species in biogeochemical cycles and in the transfer of matter in food webs is globally recognized, specific knowledge on elemental concentrations and their variability within this community is still poorly documented. Here, we report for the first time in the Bay of Biscay, North-East Atlantic, the body composition in various biological parameters and chemical elements of a meso-to bathypelagic micronektonic community. Stable carbon and nitrogen isotope compositions (δ¹³C, δ¹⁵N), C:N ratios, energy density, as well as the concentrations in 6 macro-minerals and 13 trace elements including essential (micro-nutrients) and non-essential elements (undesirables, with no know biological function) were measured in whole organisms of 4 crustacean and 11 fish species caught simultaneously around 800 m depth. The results showed a low variability of δ¹³C values, confirming that all studied species share the same habitat. On the contrary, large differences were observed among species for several elements. Trace elements showed the greatest variability (i.e. larger range of values), especially silver (Ag), arsenic (As), cadmium (Cd), cobalt and vanadium. Significant differences were also revealed among taxa for Ag, As, Cd, copper and strontium concentrations (with crustaceans > fish), as well as for δ¹⁵N values and phosphorus concentrations (with fish > crustaceans). Although concentrations varied greatly among species, they could be grouped according to their energy density and composition in 19 chemical elements, through hierarchical clustering analysis. Six functional groups of species have been thus identified, reflecting contrasted nutritional benefit and/or exposure to undesirables for predators feeding on this deep pelagic community. Finally, the concentrations measured for the potentially toxic trace elements (undesirables) exceeded the existing European thresholds for Cd and to a lesser extent mercury (Hg), which point out potential risks in the perspective of a future exploitation of these deep living resources by humans.

Characterizing the long-term occurrence of polycyclic aromatic hydrocarbons and their driving forces in surface waters

As carcinogenic and ubiquitous pollutants, an in-depth understanding of the long-term environmental behaviors of polycyclic aromatic hydrocarbons (PAHs) and their driving forces is crucial for reducing human health risks. Based on long-term monitoring data from 2001 to 2016, this study systematically investigated the temporal and seasonal trends, periodic oscillation, source apportionment, and human health risks of PAHs in eight rivers in the Free State of Saxony, Germany. The results showed that the annual average ∑₁₆PAHs (sum of 16 PAH concentrations) ranged from 28.2 ng L^-1 to 202 ng L^-1. Using the Mann-Kendall test, a trend of decreasing PAH concentrations was determined (slope range: -0.103 to -0.0159). Wavelet analysis indicated that the most significant periodic oscillation of PAHs was 10-30 months, with more pollution in winter. Source apportionment analysis suggested that vehicular emissions and coal combustion contributed the most to PAH concentrations (20.6-40.3% and 21.7-41.4%, respectively) and related health risks (54.1-80.1% and 5.61-37.9%, respectively). Furthermore, the risks (oral lifetime: 4.24×10^-7-1.34×10^-6; dermal lifetime: 2.86×10^-5-9.05×10^-5) were determined to be low. The data revealed that the substitution of petroleum and coal with cleaner energy would facilitate the mitigation of PAHs.

Polycyclic aromatic hydrocarbons (PAHs) in fishery resources affected by the 2019 oil spill in Brazil: Short-term environmental health and seafood safety

We present herein a short-term impact on marketed fisheries and human health safety in the first three months following the 2019 oil spill in Brazil. Total PAHs in the edible tissues of 34 finfish and shellfish species ranged from 8.71 to 418 ng g^-1 wet weight, with robust evidence supporting crude oil contamination. A prevalence of low molecular weight PAHs was observed, mainly naphthalenes. A decreasing trend in mean total PAHs from mollusks (134 ng g^-1) to crustaceans (73.9 ng g^-1) and to fishes (45.3 ng g^-1) was noted. The spilled oil caused immediate negative impacts on the local seafood market, despite less than 3% of samples exhibited concentrations above levels of concern, revealing a low probability for human health risks. These findings demonstrate that governments must be prepared to provide not only science-based quick responses but also effective science communication for society upon environmental disasters.

Seasonal distribution pattern and bioaccumulation of Polycyclic aromatic hydrocarbons (PAHs) in four bioindicator coastal fishes of Argentina

Polycyclic aromatic hydrocarbons (PAHs) are pollutants of global concern in coastal environments. They have a wide range of biological toxicity and due to their inherent properties, can easily bioaccumulate in organisms and concentrate in the environment. This work evaluated, in an integrated way, the seasonal PAH distribution patterns in sediments and four bioindicators fish species in a highly impacted estuary of Argentina; besides, their bioaccumulation patterns were assessed for the first time as indicator of ecological risk. The highest PAH levels in fish were found for Ramnogaster arcuata with an average of 64 ng g^-1 w.w., followed by Micropogonias furnieri (45 ng g^-1 w.w.), Cynoscion guatucupa (28 ng g^-1 w.w.), and Mustelus schmitti (16 ng g^-1 w.w.). Fish presented the highest PAH levels in fall with a predominance of petrogenic PAHs in colder seasons and pyrolytic PAHs in warmer seasons. Sediments presented an average of 233 ng g^-1 d.w. with the same seasonal composition pattern of the fish tissues. Additionally, the data suggested that the main source of PAHs are wastewater discharges. The bioaccumulation factor (BAF) of PAHs in the tested fishes were found to range from 0.3 to 8. The highest values were observed during fall and winter, while bioaccumulation did not occur in moist spring and summer samples, which would suggest a high biotransformation process during these seasons. Results suggested that class III of juvenile C. guatucupa and M. furnieri, and adults R. arcuata are more sensitive bioindicators of chronic PAH contamination and that their bioaccumulation is independent of the compound hydrophobicity; this could have a positively influence on the criteria used for biological monitoring programs along the Atlantic coast. In addition, the presented BAF data on the target species will serve as a useful pollution indicator for South Atlantic coastal fish.

Assessment of seasonal relationship between polycyclic aromatic hydrocarbon accumulation and expression patterns of oxidative stress-related genes in muscle tissues of red mullet (M. barbatus) from the Northern Adriatic Sea

In this study, we examined the seasonal association between Polycyclic Aromatic Hydrocarbon (PAH) concentrations and mRNA expression profiles of some antioxidant genes (i.e. CAT, GST and SOD), as well as lipid peroxidation (LPO), in muscle of sexually inactive females of red mullet (Mullus barbatus). Fish were captured in a fishery area of the Northern Adriatic Sea during both winter and summer. We found significantly (p < 0.05) higher ∑HMW-PAHs concentrations in muscle of specimens caught during winter than summer. On the basis of sampling season, red mullets exhibited different gene expression profiles of antioxidant enzymes showing lower levels of both CAT and GST in winter than in summer. Accordingly, CAT was found to be negatively associated with ∑PAH concentrations, especially ∑LMW-PAH, in individuals collected during winter. Seasonal-related downregulation of some oxidative stress biomarker expression is suggestive of greater susceptibility of red mullets to PAHs during winter.

A multi-taxonomic framework for assessing relative petrochemical vulnerability of marine biodiversity in the Gulf of Mexico

A fundamental understanding of the impact of petrochemicals and other stressors on marine biodiversity is critical for effective management, restoration, recovery, and mitigation initiatives. As species-specific information on levels of petrochemical exposure and toxicological response are lacking for the majority of marine species, a trait-based assessment to rank species vulnerabilities to petrochemical activities in the Gulf of Mexico can provide a more comprehensive and effective means to prioritize species, habitats, and ecosystems for improved management, restoration and recovery. To initiate and standardize this process, we developed a trait-based framework, applicable to a wide range of vertebrate and invertebrate species, that can be used to rank relative population vulnerabilities of species to petrochemical activities in the Gulf of Mexico. Through expert consultation, 18 traits related to likelihood of exposure, individual sensitivity, and population resilience were identified and defined. The resulting multi-taxonomic petrochemical vulnerability framework can be adapted and applied to a wide variety of species groups and geographic regions. Additional recommendations and guidance on the application of the framework to rank species vulnerabilities under specific petrochemical exposure scenarios, management needs or data limitations are also discussed.

Contribution of Dietary Uptake to PAH Bioaccumulation in a Simplified Pelagic Food Chain: Modeling the Influences of Continuous vs Intermittent Feeding in Zooplankton and Fish

Dietary uptake is important for trophic transfer of polycyclic aromatic hydrocarbons (PAHs) in the freshwater pelagic ecosystem. In this study, we hypothesized that both the dietary uptake rate and interval significantly influenced its relative contribution to bioaccumulation. We developed a toxicokinetic model framework for the bioaccumulation of deuterated PAHs (PAHs-d₁₀) in aquatic organisms considering different feeding intervals ranging from none for phytoplankton to approximately continuous for zooplankton to discrete for fish and built a simple artificial freshwater pelagic food chain composed of algae Chlorella vulgaris, zooplankton Daphnia magna, and zebrafish. We conducted bioaccumulation experiments and simulations for Daphnia magna and zebrafish under different algal densities based on our model. The results showed that intermittent feeding led to a large fluctuation in the PAH-d₁₀ concentrations in zebrafish compared to a leveled-off pattern in Daphnia magna because of approximately continuous feeding. Trophic dilution of PAHs-d₁₀ occurred in the food chain when there was waterborne-only uptake, but dietary uptake largely mitigated its extent that depended on dietary uptake rates. The assimilation efficiency, dietary uptake rate, and its relative contribution to bioaccumulation of PAHs-d₁₀ in zebrafish were all higher than those in Daphnia magna, suggesting that dietary uptake played a more important role in bioaccumulation of PAHs at higher trophic-level organisms.

PAH and PCB body-burdens in epibenthic deep-sea invertebrates from the northern Gulf of Mexico

There is a paucity of information on the levels of PAHs and PCBs in the deep-sea (≥200 m). In this study, the body-burdens of 16 PAHs and 29 PCBs were measured in: Actinaria (sea anemones), Holothuroidea (sea cucumber), Pennatulacea (sea pens), and Crinoidea (sea lilies) in the deep Gulf of Mexico. All epibenthic species were collected at depths of approximately 2000 m. The PAH and PCB congener profile displayed a similar pattern of bioaccumulation across all four taxa. The high molecular weight PAH, dibenz[a,h]anthracene, was the most abundant PAH in all organisms, ranging from 36 to 53% of sum total PAHs. PCBs 101 and 138 exhibited the highest levels at 20-25% of total congener concentrations in all taxa. The exposure to PAHs and PCBs is likely attributed to contaminated particulate organic matter that is consumed by the deposit and filter feeding epibenthic megafauna sampled in this study.

Marine Snow Aggregates are Enriched in Polycyclic Aromatic Hydrocarbons (PAHs) in Oil Contaminated Waters: Insights from a Mesocosm Study

Marine snow was implicated in the transport of oil to the seafloor during the Deepwater Horizon oil spill, but the exact processes remain controversial. In this study, we investigated the concentrations and distributions of the 16 USEPA priority polycyclic aromatic hydrocarbons (PAHs) in marine snow aggregates collected during a mesocosm experiment. Seawater only, oil in a water accommodated fraction (WAF), and Corexit-enhanced WAF (DCEWAF) were incubated for 16 d. Both WAF and DCEWAF aggregates were enriched in heavy molecular weight PAHs but depleted in naphthalene. DCEWAF aggregates had 2.6 times more total 16 PAHs than the WAF (20.5 vs. 7.8 µg/g). Aggregates in the WAF and DCEWAF incorporated 4.4% and 19.3%, respectively of the total PAHs in the mesocosm tanks. Our results revealed that marine snow sorbed and scavenged heavy molecular weight PAHs in the water column and the application of Corexit enhanced the incorporation of PAHs into the sinking aggregates.

Maternal occupational exposure to polycyclic aromatic hydrocarbons and the risk of isolated congenital heart defects among offspring

BACKGROUND

Although there is evidence in experimental model systems that exposure to polycyclic aromatic hydrocarbons (PAHs) is linked with congenital heart defects (CHDs), few studies have examined the association in humans. We conducted a case-control study to examine the association between maternal exposure to PAHs and CHDs in offspring using data from the National Birth Defects Prevention Study (NBDPS) (1997-2011).

METHODS

We obtained detailed information on maternal occupation during the month before to three months after conception. Expert raters, masked to case-control status, assessed job descriptions to assign categorical levels of exposure. Categories were quantitatively mapped to estimate cumulative exposure to PAHs, incorporating exposure intensity, frequency, work duration, and work hours. Quartiles were generated for cumulative maternal exposure to PAHs. Crude and adjusted odds ratios (ORs) with 95% confidence intervals (CIs) were estimated using unconditional logistic regression for quartiles of PAH exposure and six CHD groupings (e.g. conotruncal) and specific subtypes (e.g. tetralogy of Fallot [ToF]). Final models were adjusted for maternal age, race/ethnicity, education, smoking, anticonvulsant use, folic acid supplementation, and study center.

RESULTS

There were 4,775 case and 7,734 control infants eligible for the study. The prevalence of occupational exposure to PAHs was 10.2% among both case and control mothers. In adjusted analysis, compared to mothers with no occupational PAH exposure, those in the highest quartile of exposure were more likely to have offspring in the conotruncal heart defects group (OR 1.41; 95% CI 1.00-2.00), and with ToF (OR 1.83; 95% CI 1.21-2.78).

CONCLUSIONS

Women in the highest quartile of estimated cumulative occupational PAH exposure during early pregnancy were more likely to have offspring with conotruncal heart defects, specifically ToF, compared to women with no occupational PAH exposure. Other comparisons between PAHs and other CHDs subgroups did not show any statistically precise associations.

Effects of biological factors and seasonality on the level of polycyclic aromatic hydrocarbons in red mullet (Mullus barbatus)

This study evaluates the effects of biological factors of fish and seasonality on Polycyclic Aromatic Hydrocarbon (PAH) accumulation in red mullet (Mullus barbatus) tissue. Specimens were collected monthly with a bottom trawl net in an offshore fishing ground in the Northern and Central Adriatic Sea (Geographical Sub Area 17) throughout 2016. The edible fillets of 380 individuals were analyzed for the concentrations of individual PAH, total PAH, and low, medium and high molecular weight (MW) PAHs. PAH bioaccumulation was related to their physicochemical characteristics (MW, and logarithm of the octanol-water partition coefficient, log K_ow), some biological parameters of fish (body size, age, sex, reproductive stage and total lipid content), and catch season. The PAH bioaccumulation pattern and the effects of the different factors varied according to PAH MW. The heavier (medium and high MW) PAHs showed higher levels in winter-autumn and in pre-spawners compared with spawners and post-spawners. Our findings suggest that an important detoxification mechanism, albeit limited to the heavier PAHs, acts in the spawning and post-spawning stage. Low MW PAHs appeared to be unaffected by reproductive stage, lipid content and seasonality. Reproductive stage and seasonality seem to play an important role in the accumulation of heavier PAH, whereas total lipid content and age seem to exert a limited influence, and body size no effect at all.

Toxicities of Polycyclic Aromatic Hydrocarbons for Aquatic Animals

Polycyclic aromatic hydrocarbons (PAHs) are organic compounds that are widely distributed in the air, water, and soil. Recently, the amount of PAHs derived from fuels and from incomplete combustion processes is increasing. In the aquatic environment, oil spills directly cause PAH pollution and affect marine organisms. Oil spills correlate very well with the major shipping routes. Furthermore, accidental oil spills can seriously impact the marine environment toxicologically. Here, we describe PAH toxicities and related bioaccumulation properties in aquatic animals, including invertebrates. Recent studies have revealed the toxicity of PAHs, including endocrine disruption and tissue-specific toxicity, although researchers have mainly focused on the carcinogenic toxicity of PAHs. We summarize the toxicity of PAHs regarding these aspects. Additionally, the bioaccumulation properties of PAHs for organisms, including invertebrates, are important factors when considering PAH toxicity. In this review, we describe the bioaccumulation properties of PAHs in aquatic animals. Recently, microplastics have been the most concerning environmental problem in the aquatic ecosystem, and the vector effect of microplastics for lipophilic compounds is an emerging environmental issue. Here, we describe the correlation between PAHs and microplastics. Thus, we concluded that PAHs have a toxicity for aquatic animals, indicating that we should emphasize the prevention of aquatic PAH pollution.

Experimental Approaches for Characterizing the Endocrine-Disrupting Effects of Environmental Chemicals in Fish

Increasing industrial and agricultural activities have led to a disturbing increase of pollutant discharges into the environment. Most of these pollutants can induce short-term, sustained or delayed impacts on developmental, physiological, and behavioral processes that are often regulated by the endocrine system in vertebrates, including fish, thus they are termed endocrine-disrupting chemicals (EDCs). Physiological impacts resulting from the exposure of these vertebrates to EDCs include abnormalities in growth and reproductive development, as many of the prevalent chemicals are capable of binding the receptors to sex steroid hormones. The approaches employed to investigate the action and impact of EDCs is largely dependent on the specific life history and habitat of each species, and the type of chemical that organisms are exposed to. Aquatic vertebrates, such as fish, are among the first organisms to be affected by waterborne EDCs, an attribute that has justified their wide-spread use as sentinel species. Many fish species are exposed to these chemicals in the wild, for either short or prolonged periods as larvae, adults, or both, thus, studies are typically designed to focus on either acute or chronic exposure at distinct developmental stages. The aim of this review is to provide an overview of the approaches and experimental methods commonly used to characterize the effects of some of the environmentally prevalent and emerging EDCs, including 17 α-ethinylestradiol, nonylphenol, BPA, phthalates, and arsenic; and the pervasive and potential carriers of EDCs, microplastics, on reproduction and growth. In vivo and in vitro studies are designed and employed to elucidate the direct effects of EDCs at the organismal and cellular levels, respectively. In silico approaches, on the other hand, comprise computational methods that have been more recently applied with the potential to replace extensive in vitro screening of EDCs. These approaches are discussed in light of model species, age and duration of EDC exposure.

Effects of pollution on marine organisms

This review covers selected 2018 articles on the biological effects of pollutants, including human physical disturbances, on marine and estuarine plants, animals, ecosystems, and habitats. The review, based largely on journal articles, covers field and laboratory measurement activities (bioaccumulation of contaminants, field assessment surveys, toxicity testing, and biomarkers) as well as pollution issues of current interest including endocrine disrupters, emerging contaminants, wastewater discharges, marine debris, dredging, and disposal. Special emphasis is placed on effects of oil spills and marine debris due largely to the 2010 Deepwater Horizon oil blowout in the Gulf of Mexico and proliferation of data on the assimilation and effects of marine debris. Several topical areas reviewed in the past (e.g., mass mortalities ocean acidification) were dropped this year. The focus of this review is on effects, not on pollutant sources, chemistry, fate, or transport. There is considerable overlap across subject areas (e.g., some bioaccumulation data may be appear in other topical categories such as effects of wastewater discharges, or biomarker studies appearing in oil toxicity literature). Therefore, we strongly urge readers to use keyword searching of the text and references to locate related but distributed information. Although nearly 400 papers are cited, these now represent a fraction of the literature on these subjects. Use this review mainly as a starting point. And please consult the original papers before citing them.

Assemblage structure, vertical distributions and stable-isotope compositions of anguilliform leptocephali in the Gulf of Mexico

In August 2007, October 2008 and September-October 2010, 241 Tucker trawl and plankton net tows were conducted at the surface to depths of 1377 m at six locations in the northern and eastern Gulf of Mexico (GOM) to document leptocephalus diversity and determine how assemblage structure, larval size, abundance and isotopic signatures differ across the region and with depth. Overall, 2696 leptocephali representing 59 distinct taxa from 10 families were collected. Five families accounted for 96% of the total catch with Congridae and Ophichthidae being the most abundant. The top four most abundant species composed 59% of the total catch and included: Ariosoma balearicum, Paraconger caudilimbatus, Rhynchoconger flavus and Ophichthus gomesii. Four anguilliform species not previously documented in the GOM as adults or leptocephali were collected in this study, including Monopenchelys acuta, Quassiremus ascensionis, Saurenchelys stylura and one leptocephalus only known from its larval stage, Leptocephalus proboscideus. Leptocephalus catches were significantly greater at night than during the day. Catches at night were concentrated in the upper 200 m of the water column and significantly declined with increasing depth. Leptocephali abundances and assemblages were significantly different between sites on the upper continental slope (c. 500 m depth) and sites on the middle to lower continental slope (c. 1500-2300 m). Sites on the lower continental slope had a mixture of deep-sea demersal, bathypelagic and coastal species, whereas upper-slope sites contained several numerically dominant species (e.g., A. balearicum, P. caudilimbatus) that probably spawn over the continental shelf and upper slope of the GOM. Standard lengths of the four dominant species differed between sites and years, indicating heterochronic reproduction and potential larval source pools within and outside of the GOM. Stable-isotope analyses (δ¹³ C and δ¹⁵ N) conducted on 185 specimens from six families revealed that leptocephali had a wide range of isotopic values at the family and size-class levels. Species in the families Muraenidae, Congridae and Ophichthidae had similar δ¹⁵ N values compared with the broad range of δ¹⁵ N values seen in the deep-sea families Nemichthyidae, Nettastomatidae and Synaphobranchidae. Stable-isotope values were variably related to length, with δ¹⁵ N values being positively size correlated in ophichthids and δ¹³ C values being negatively size correlated in A. balearicum and P. caudilimbatus. Results suggest that leptocephali feed in various water depths and masses, and on different components of POM, which could lead to niche partitioning. Ecological aspects of these important members of the plankton community provide insight into larval connectivity in the GOM as well as the early life history of Anguilliformes.