Health risk indices and zooplankton-based assessment of a tropical rainforest river contaminated with iron, lead, cadmium, and chromium.

Oil exploration's devastation on health and the environment may far outweigh its economic benefits. An oil spill occurred at Egbokodo River in Delta State, Nigeria, thereby polluting the land and water bodies. The study was therefore aimed at evaluating the impacts of iron, lead, cadmium, and chromium on the zooplankton community structure of Egbokodo River and the potential health risks. Zooplankton and surface water samples were collected to investigate the concentrations of trace metals and zooplankton abundance. The associated carcinogenic and non-carcinogenic effects of the metals in the water were analyzed. Trace metal concentrations in the surface water were determined using atomic absorption spectroscopy (Philips model PU 9100) and zooplankton samples were collected using a hydrobios plankton net (mesh size 25 µm). Total petroleum hydrocarbons (TPH) and oil and grease (OG) were determined using Agilent 7890B gas chromatography coupled to flame ionization detector (GC-FID) and volumetric analysis respectively. The trend of the abundance of zooplanktons cross the river was 18 individuals (Station A) < 100 individuals (Station B) < 155 individuals (Station C). Cyclopoida proved to be the most resilient to the impacts of the oil spill. On a taxa basis, the order of abundance among Calanoida, Cyclopoida, Cladoceran, and Harpacticoida was Station C > Station B > Station A, except in Amphipoda where Station B > Station C > Station A was observed. Iron and lead posed significant carcinogenic risks that are liable to be inflicted by the ingestion of the water. The cumulative non-carcinogenic health risk in the male was the only significant (> 1) among the age groups. Total petroleum hydrocarbons (TPH), oil and grease (OG), iron, and lead had notable impacts on the general abundance of zooplankton in the aquatic habitat. The dominance of the Cyclopoida in the river buttressed the impact of the oil spill which warrants a prompt remediation measure. The pollution had notable ecological impacts on the zooplankton community structure of the aquatic habitat. The adults in the nearby human populations are liable to elicit carcinogenic health challenges associated with lead and iron ingestion. The males are at risk of non-carcinogenic illnesses which are associated with the combined toxicity effects of all the metals. The study suggests that the pollution in Egbokodo River was validated by the dominance of the Cyclopoida in the aquatic habitat. The study confers bioindicator reputation on the Cyclopoida for future biomonitoring studies.

Evaluation of skin irritation following weathered crude oil exposure in two mouse strains.

Petroleum crude oil spills are common and vary in size and scope. Spill response workers throughout the course of remediation are exposed to so-called weathered oil and are known to report diverse health effects, including contact dermatitis. A murine model of repeated exposure to weathered marine crude oil was employed utilizing two strains of mice, C57BL/6 and BALB/c, to investigate the pathology of this irritant and identify the principal hydrocarbon components deposited in skin. Histopathology demonstrated clear signs of irritation in oil-exposed skin from both mouse strains, characterized by prominent epidermal hyperplasia (acanthosis). BALB/c mice exposed to oil demonstrated more pronounced irritation compared with C57BL/6 mice, which was characterized by increased acanthosis as well as increased inflammatory cytokine/chemokine protein expression of IL-1ß, IL-6, CXCL10, CCL2, CCL3, CCL4, and CCL11. A gas chromatography/mass spectrometry method was developed for the identification and quantification of 42 aliphatic and EPA priority aromatic hydrocarbons from full thickness skin samples of C57BL/6 and BALB/c mice exposed to oil samples. Aromatic hydrocarbons were not detected in skin; however, aliphatic hydrocarbons in skin tended to accumulate with carbon numbers greater than C16. These preliminary data and observations suggest that weathered crude oil is a skin irritant and this may be related to specific hydrocarbon components, although immune phenotype appears to impact skin response as well.

Diatom aggregation when exposed to crude oil and chemical dispersant: Potential impacts of ocean acidification.

Diatoms play a key role in the marine carbon cycle with their high primary productivity and release of exudates such as extracellular polymeric substances (EPS) and transparent exopolymeric particles (TEP). These exudates contribute to aggregates (marine snow) that rapidly transport organic material to the seafloor, potentially capturing contaminants like petroleum components. Ocean acidification (OA) impacts marine organisms, especially those that utilize inorganic carbon for photosynthesis and EPS production. Here we investigated the response of the diatom Thalassiosira pseudonana grown to present day and future ocean conditions in the presence of a water accommodated fraction (WAF and OAWAF) of oil and a diluted chemically enhanced WAF (DCEWAF and OADCEWAF). T. pseudonana responded to WAF/DCEWAF but not OA and no multiplicative effect of the two factors (i.e., OA and oil/dispersant) was observed. T. pseudonana released more colloidal EPS (< 0.7 µm to > 3 kDa) in the presence of WAF/DCEWAF/OAWAF/OADCEWAF than in the corresponding Controls. Colloidal EPS and particulate EPS in the oil/dispersant treatments have higher protein-to-carbohydrate ratios than those in the control treatments, and thus are likely stickier and have a greater potential to form aggregates of marine oil snow. More TEP was produced in response to WAF than in Controls; OA did not influence its production. Polyaromatic hydrocarbon (PAH) concentrations and distributions were significantly impacted by the presence of dispersants but not OA. PAHs especially Phenanthrenes, Anthracenes, Chrysenes, Fluorenes, Fluoranthenes, Pyrenes, Dibenzothiophenes and 1-Methylphenanthrene show major variations in the aggregate and surrounding seawater fraction of oil and oil plus dispersant treatments. Studies like this add to the current knowledge of the combined effects of aggregation, marine snow formation, and the potential impacts of oil spills under ocean acidification scenarios.

Micro-algal astaxanthin could improve the antioxidant capability, immunity and ammonia resistance of juvenile Chinese mitten crab, Eriocheir sinensis.

Green alga Haematococcus pluvialis is an important source of natural astaxanthin (Ast), which have been shown to be beneficial for the color formulation, survival, antioxidation, immunity and stress resistance of many crustacean. This study was conducted to investigate the effects of dietary supplementation of H. pluvialis meal on growth, antioxidant status, ammonia resistance, color parameters, and carotenoids composition of juvenile Chinese mitten crab Eriocheir sinensis. Five diets were formulated to contain 0, 30, 60, 90 and 120 mg/kg dry diets of natural Ast (defined as Diet 1-5) using H. pluvialis meal as astaxanthin source. The results showed that: (1) Although all treatments with Ast supplementation had the relatively higher growth performance and survival than the control (Diet 1 treatment), no significant differences were found on growth performance, feed conversion ratio and hepatosomatic index among all treatments. (2) The highest total antioxidant capacity (T-AOC) in hepatopancreas and hemolymph were observed in Diet 4 and 3 treatments respectively, while the lowest malondialdehyde (MDA) contents in hepatopancreas and hemolymph were also found in these two treatments. Furthermore, the significantly positive relationships were detected on acid phosphatase (ACP) activities and dietary Ast contents for hepatopancreas and hemolymph. (3) Diet 3 treatment had the highest mRNA levels of EsLecA, EsTrx, and EsPrx6 in hepatopancreas, while both Diet 3 and 4 treatments reached the peaks for mRNA expression levels of EsMyd88 and EsHc, respectively. (4) The stress test with ammonia-N indicated Diet 1 treatment had the highest mortality among all treatments, and the lowest mortality was found on Diet 3 treatment during the stress test. (5) Dietary Ast significantly improved the redness (a*) of carapace and hepatopancreas, which were consistent with the Ast contents in these tissues from the different treatments. Ast concentrations in carapace reached the plateau for Diet 3 treatment while hepatopancreatic Ast concentration kept increasing with elevating dietary Ast contents. In conclusion, natural astaxanthin could enhance the antioxidative capability, non-specific immunity, tissue Ast contents and stress resistance to ammonia-N, and these results suggested the optimal diet micro-algal astaxanthin was around 60 mg/kg for juvenile E. sinensis.

Impact of wastewater effluent pollution on stream functioning: A whole-ecosystem manipulation experiment.

The ecological effects of wastewater treatment plant (WWTP) effluents on stream ecosystems cause growing concern. However, it is difficult to assess these effects as most streams receiving WWTP effluents are also affected by other stressors. We performed a whole-ecosystem manipulation experiment following a BACI design (Before-After/Control-Impact) in order to exclude the influence of other potentially confounding factors. We diverted part of the effluent of a large tertiary urban WWTP into a small, unpolluted stream, and studied its effects on ecosystem structure and functioning over two years (i.e., one year before and one year after the effluent diversion). Although highly diluted (final concentration in the receiving stream averaged 3%), the effluent promoted biofilm chlorophyll-a and biomass (2.3 and 2.1 times, respectively), exo-enzymatic activities (phosphatase 2.2 and glucosidase 4.2 times) and invertebrate-mediated organic matter decomposition (1.4 times), but reduced phosphorus uptake capacity of the epilithic biofilm down to 0.5 of the initial values. Biofilm metabolism, reach-scale nutrient uptake and microbially-mediated organic matter decomposition were not affected. Our results indicate that even well treated and highly diluted WWTP effluents can also affect the structure of the biofilm community and stream ecosystem functioning.

Parental stressor exposure simultaneously conveys both adaptive and maladaptive larval phenotypes through epigenetic inheritance in the zebrafish (Danio rerio).

Genomic modifications occur slowly across generations, whereas short-term epigenetic inheritance of adaptive phenotypes may be immediately beneficial to large numbers of individuals, acting as a bridge for survival when adverse environments occur. In the present study, crude oil was used as an example of an environmental stressor. Adult zebrafish (P0) were dietarily exposed for 3 weeks to no, low, medium or high concentrations of crude oil. The F1 offspring obtained from the P0 groups were then assessed for transgenerational epigenetic transfer of oil-induced phenotypes. The exposure did not alter body length, body and organ mass or condition factor in the P0 groups. However, the P0 fecundity of both sexes decreased in proportion to the amount of oil fed. The F1 larvae from each P0 were then exposed from 3 hpf to 5 dpf to oil in their ambient water. Remarkably, F1 larvae derived from oil-exposed parents, when reared in oiled water, showed a 30% enhanced survival compared with controls (P<0.001). Unexpectedly, from day 3 to 5 of exposure, F1 larvae from oil-exposed parents showed poorer survival in clean water (up to 55% decreased survival). Additionally, parental oil exposure induced bradycardia (presumably maladaptive) in F1 larvae in both clean and oiled water. We conclude that epigenetic transgenerational inheritance can lead to an immediate and simultaneous inheritance of both beneficial and maladaptive traits in a large proportion of the F1 larvae. The adaptive responses may help fish populations survive when facing transient environmental stressors.

Oil degradation potential of microbial communities in water and sediment of Baltic Sea coastal area.

Two long-term potentially oil exposed Baltic Sea coastal sites near old oil refineries and harbours were compared to nearby less exposed sites in terms of bacterial, archaeal and fungal microbiomes and oil degradation potential. The bacterial, archaeal and fungal diversities were similar in oil exposed and less exposed sampling sites based on bacterial and archaeal 16S rRNA gene and fungal 5.8S rRNA gene amplicon sequencing from both DNA and RNA fractions. The number of genes participating in alkane degradation (alkB) or PAH-ring hydroxylation (PAH-RHDα) were detected by qPCR in all water and sediment samples. These numbers correlated with the number of bacterial 16S rRNA gene copies in sediment samples but not with the concentration of petroleum hydrocarbons or PAHs. This indicates that both the clean and the more polluted sites at the Baltic Sea coastal areas have a potential for petroleum hydrocarbon degradation. The active community (based on RNA) of the coastal Baltic Sea water differed largely from the total community (based on DNA). The most noticeable difference was seen in the bacterial community in the water samples were the active community was dominated by Cyanobacteria and Proteobacteria whereas in total bacterial community Actinobacteria was the most abundant phylum. The abundance, richness and diversity of Fungi present in water and sediment samples was in general lower than that of Bacteria and Archaea. Furthermore, the sampling location influenced the fungal community composition, whereas the bacterial and archaeal communities were not influenced. This may indicate that the fungal species that are adapted to the Baltic Sea environments are few and that Fungi are potentially more vulnerable to or affected by the Baltic Sea conditions than Bacteria and Archaea.

Phosphorus enriched effluents increase eutrophication risks for mangrove systems in northeastern Brazil.

Discharge of effluents loaded with phosphorus (P) from anthropogenic activities constitutes serious eutrophication risks in marine and terrestrial ecosystems, including mangroves. Three mangroves in NE-Brazil were studied to evaluate the impact of P-rich-effluents from shrimp farming and domestic sewage, in relation to a control area (natural mangrove). Soil phosphorus fractionation and water chemical analysis were performed to assess potential pollution. We observed the most labile P forms increased gradually and significantly from control to sewage to shrimp farm impacted mangroves as observed by increasingly dissolved orthophosphate (PO43-) content in water and the exchangeable/soluble P (Exch-P) extracted from soils, which is supported by the discriminant analysis. Exch-P results were correlated to Humic-Acid-P, which can release more labile P forms when mineralized. Our results demonstrate a substantial impact of aquiculture and sewage effluents in mangroves at both organic and inorganic P fractions, raising important concerns regarding pollution for these marine ecosystems.

Temporal changes in biological traits of diatom communities in response to an oil spill in a subtropical river.

Diatom growth strategies, which are used as a proxy to analyze disturbances and environmental impacts, can also provide reliable information about environmental gradients. In this study, we used diatom communities and biological traits to assess the structure of epilithic diatoms after an oil spill in a large tributary of the Iguaçu River (Paraná, Brazil). Epilithon and water samples were taken on July 12th, 2004, and after an unexpected oil spill, on the following days: 09/19, 10/03, and 10/13/2004. We observed that the spill caused a distinct shift in both diatom composition and guild group. Diversity decreased and pollution-tolerant diatoms of the motile group became dominant in response to the elevated nutrient levels and reduced light. Tube-forming diatoms, which are strong competitors for light, dominated the epilithon 24 days after the oil spill. Both diatom guilds and growth forms were successfully used to predict the environmental conditions. While diatom guilds responded to disturbances along a temporal gradient, changes inside the guilds were the main factor for understanding the environmental gradient.

High fat diet worsens the adverse effects of antibiotic on intestinal health in juvenile Nile tilapia (Oreochromis niloticus).

Antibiotics and high fat diets are commonly used independently in global aquaculture production for fish health management and to spare the use of costly protein as energy sources, respectively, causing relatively similar metabolic effects and stresses. However, it is unknown whether dietary high fat worsens or attenuates the adverse effects caused by antibiotics in fish. We determined the ability of high fat diet to influence the adverse effects of oxytetracycline on Nile tilapia, Oreochromis niloticus. Thirty Nile tilapia weighing 8.45 ±â€¯0.15 g were fed on medium fat (MF; 70 g/kg) and high fat (HF; 120 g/kg) diets and the same fat levels supplemented with 2.00 g/kg diet of OTC (80 mg/kg body weight/day) hereafter, MFO and HFO for 65 days. The general growth performance, feed efficiency and intestinal health of fish were evaluated. The Nile tilapia fed on HFO diet had significantly lower growth rate, body protein content and feed efficiency compared to those fed on MFO diet. Dietary HFO affected the intestine histomorphology, which decreased dramatically the tight junction proteins of Nile tilapia and induced microbiota dysbiosis compared to MFO diet. The Nile tilapia fed on HFO diet had increased oxidative stress, which stimulated drug detoxification response, caused endoplasmic reticulum stress and apoptosis compared to those fed on MFO diet. The new findings from our study demonstrate that, the adverse effects of antibiotics in fish are different at medium and high fat contents. Feeding fish with high fat diets with antibiotics worsen the adverse effects. This enlightens our understanding on the risks of antibiotics misuse and also suggests that antibiotics should be more strictly limited in aquaculture, in which high fat diets are currently widely used in fish production worldwide.

Response of a novel selenium-dependent glutathione peroxidase from thick shell mussel Mytilus coruscus exposed to lipopolysaccharide, copper and benzo[α]pyrene.

Glutathione peroxidase (GPx) plays an important antioxidant role in cellular defense against environmental stress. In the present study, a novel selenium-dependent glutathione peroxidase termed McSeGPx firstly identified in thick shell mussel Mytilus coruscus. McSeGPx consists of 197 amino acid residues, characterized with one selenocysteine residue encoded by an opal stop codon TGA, one selenocysteine insertion sequence (SECIS) in the 3' untranslated region (UTR), two active site motifs and one signature sequence motif. McSeGPx transcripts were constitutively expressed in all examined tissues, and were significantly induced in gills and digestive glands with the stimulations of lipopolysaccharide (LPS), copper (Cu) and benzo[α]pyrene (B[α]P). Additionally, rough increases in McSeGPx activity were detected in both tissues under the challenge of LPS, Cu and B[α]P. Collectively, these results suggested that McSeGPx affiliate to selenocysteine dependent GPx (SeGPx) family and might play an important role in mediating the environmental stressors and antioxidant response in M. coruscus.

Biosurfactant-modified palygorskite clay as solid-stabilizers for effective oil spill dispersion.

An effective and conventional remediation technique in marine oil spills is to apply chemical dispersants to emulsify oil slicks into small oil droplets. Still, the potential hazards of chemical dispersants onto the marine ecosystem have motivated the research for environmentally friendly alternative while keeping exceptional dispersion ability. Here, we showed that the mixture of palygorskite (PAL) and rhamnolipid (Rha) formed a biocompatible alternative to synthetic surfactants used for oil spill dispersion. The oil droplets dispersed by R-PAL presented a small average size and long-term stability, which illustrated the synergistic interactions between Rha and PAL acting as an efficient dispersant in artificial sea water (ASW). Due to the strong flocculation caused by high salinity, PAL alone was not effective emulsifiers in ASW. A small amount of Rha could played a major role in modifying the surface characteristics of PAL and decreasing oil-water interfacial tension. Therefore, PAL particles irreversibly adsorbed onto the oil-ASW interface and formed a rigid interfacial film around oil droplets in the presence of Rha, which offered an efficient barrier to droplet coalescence. The synergistic interactions between PAL and Rha could enable the dispersion of tetradecane in ASW. Such a functionality was further tested in dispersing crude oil in ASW. The study presents a new strategy of using a mixture of PAL and Rha for oil dispersion, thus providing an ecofriendly alternative to conventional dispersants.

From collection to discharge: physical, chemical, and biological analyses for fish farm water quality monitoring.

The use of chemical substances for the management of fish farming activities may compromise the quality of the tank water itself and of water bodies that receive the effluents. As studies that assess the environmental effect caused by pisciculture are scarce, the present study aimed at evaluating the water quality in two fish farms in the region of Grande Dourados, Brazil, from the site of water collection to the site of water disposal. The tools used for this purpose were the analysis of land use and cover and the determination of physical, chemical, and biological parameters of water samples. Maps of land use and cover were created, and water samples were collected at four sampling sites in two fish farms. The Allium cepa test, assays with Astyanax lacustris, and the Salmonella/microsome assay were performed. In addition, physical and chemical parameters were measured and metal and emerging contaminants in the water samples were investigated. The A. lacustris demonstrated the genotoxicity and the Salmonella/microsome assay suggested the mutagenic potential of water samples from the fish farms and indicated higher genotoxicity in the disposal tanks than in the collection tanks of the Brilhante fish farm. However, all the samples at the Dourados fish farm were genotoxic, and mutagenicity was shown to start at the water collection site. With regard to the A. cepa test, there was no statistical difference between the collection sites in both fish farms. Moreover, the observed genetic damage may be associated with the presence of metals and emerging contaminants in the water samples, which suggests that these chemicals have potential genotoxic and mutagenic effects that are related to the type of land use and cover in the area of the region studied. Considering that contaminated waters can potentially disturb the structure and functioning of natural ecosystems, the present study demonstrated the importance of treating fish farm effluent to minimize the negative effect of this activity on water bodies.

Interactions between Microcystis aeruginosa and coexisting bisphenol A at different phosphorus levels.

Microcystis aeruginosa is known as the main contributor to cyanobacterial bloom, which is prevalent globally and degrades freshwater systems worldwide. The argument that the introduction of anthropogenic contaminants in fresh water stimulates cyanobacterial growth and microcystin production has attracted widespread attention. Bisphenol A (BPA), one of the most abundant endocrine-disrupting compounds, is often detected in various water bodies due to its notably high annual levels of production and use. Research on the combined effects of endocrine-disrupting compounds and environmental factors on cyanobacteria remains limited. To investigate the mechanism of interactions between contaminants and cyanobacteria at the cellular and proteomic levels, the growth rate, chlorophyll-a content, photosynthetic activities, microcystin-LR (MC-LR) production and release, reactive oxygen species (ROS) content, superoxide dismutase (SOD) activities, malondialdehyde (MDA) content, and proteome expression of M. aeruginosa under 1 µM BPA stress at a standard phosphorus level were investigated. The results showed that stress responses to BPA included increases in the growth rate, chlorophyll-a content, and Fv/Fm and rETRmax values under the low phosphorus condition. Responses involving ROS, SOD, and MDA indicated that phosphorus sufficiency and BPA caused oxidative stress in M. aeruginosa. Moreover, phosphorus sufficiency and BPA stimulated the production and release of MCs. Compared to levels in the non-BPA-treated group, exposure of M. aeruginosa to BPA caused 72 up-regulated proteins, which were primarily associated with photosynthesis, ribosome, fatty acid biosynthesis, glycolysis/glyconeogenesis, and carbon fixation in photosynthetic organisms. The 105 down-regulated proteins were related to quorum sensing, base excision repair, ABC transporters, longevity regulating and cell cycle-caulobacter, suggesting that the cytotoxicity of cyanobacterial cells induced by BPA was significantly increased. These findings provide insights into the molecular mechanism of the effects of BPA and phosphorus on M. aeruginosa, suggesting that coexisting pollutants may cause greater harm to and health risks in the environment.

Nitrate in drinking water and vegetables: intake and risk assessment in rural and urban areas of Nagpur and Bhandara districts of India.

The study focuses on the estimation of health risk from nitrate present in the drinking water and vegetables in Nagpur and Bhandara districts in the state of Maharashtra, India. Drinking water samples from 77 locations from the rural as well as urban areas and 22 varieties of vegetable were collected and analyzed for the presence of nitrate for a period of 1 year (two seasons). The daily intake of nitrate from these water and vegetable samples was then computed and compared with standard acceptable intake levels to assess the associated health risk. The mean nitrate concentration of 59 drinking water samples exceeded the Bureau of Indian Standards limit of 45 mg/L in drinking water. The rural and urban areas were found to have mean nitrate concentration in drinking water as 45.69 ± 2.08 and 22.53 ± 1.97 mg/L, respectively. The estimated daily intake of drinking water samples from 55 study sites had nitrate concentration far below the safety margin indicating serious health risk. The sanitation survey conducted in 12 households reported contaminated source with positive E. coli count in 20 samples as the major factor of health risk. The average nitrate concentration was maximum in beetroot (1349.38 mg/kg) followed by spinach (1288.75 mg/kg) and amaranthus (1007.64 mg/kg). Among the samples, four varieties of the vegetables exceeded the acceptable daily intake (ADI) with an assumption of 0.5 kg consumption of vegetables for an average of a 60-kg individual. Therefore, irrigation of these locally grown vegetables should be monitored periodically for nitrogen accumulation by the crop above the ADI limit. The application of nitrogenous fertilizers should also be minimized in the rural areas to help protect the nitrate contamination in groundwater sources.

Deepwater Horizon oil spill exposures and nonfatal myocardial infarction in the GuLF STUDY.

BACKGROUND: Workers involved in the response and clean-up of the 2010 Deepwater Horizon oil spill faced possible exposures to crude oil, burning oil, dispersants and other pollutants in addition to physical and emotional stress. These exposures may have increased risk of myocardial infarction (MI) among oil spill workers. METHODS: Gulf Long-term Follow-up (GuLF) STUDY participants comprise individuals who either participated in the Deepwater Horizon response efforts or registered for safety training but were not hired. Oil spill-related exposures were assessed during enrollment interviews conducted in 2011-2013. We estimated risk ratios (RR) and 95% confidence intervals for the associations of clean-up work characteristics with self-reported nonfatal MI up to three years post-spill. RESULTS: Among 31,109 participants without history of MI prior to the spill, 77% worked on the oil spill. There were 192 self-reported MI during the study period; 151 among workers. Among the full cohort, working on the oil spill clean-up (vs not working on the clean-up) and living in proximity to the oil spill (vs further away) were suggestively associated with a possible increased risk of nonfatal MI [RR: 1.22 (0.86, 1.73) and 1.15 (0.82, 1.60), respectively]. Among oil spill workers, working for > 180 days was associated with MI [RR for > 180 days (vs 1-30 days): 2.05 (1.05, 4.01)], as was stopping working due to heat [RR: 1.99 (1.43, 2.78)]. There were suggestive associations of maximum total hydrocarbon exposure ≥3.00 ppm (vs < 0.30 ppm) [RR: 1.69 (0.90, 3.19)] and working on decontaminating oiled equipment (vs administrative support) [1.72 (0.96, 3.09)] with nonfatal MI. CONCLUSION: This is the first study to assess the associations between oil spill exposures and MI. Results suggest that working on the spill for > 180 days and stopping work due to heat increased risk of nonfatal MI. Future research should evaluate whether the observed associations are related to specific chemical exposures or other stressors associated with the spill.

The impact of the Deepwater Horizon blowout on historic shipwreck-associated sediment microbiomes in the northern Gulf of Mexico.

More than 2,000 historic shipwrecks spanning 500 years of history, rest on the Gulf of Mexico seafloor. Shipwrecks serve as artificial reefs and hotspots of biodiversity by providing hard substrate, something rare in deep ocean regions. The Deepwater Horizon (DWH) spill discharged crude oil into the deep Gulf. Because of physical, biological, and chemical interactions, DWH oil was deposited on the seafloor, where historic shipwrecks are present. This study examined sediment microbiomes at seven historic shipwrecks. Steel-hulled, World War II-era shipwrecks and wooden-hulled, 19th century shipwrecks within and outside of the surface oiled area and subsurface plume were examined. Analysis of 16S rRNA sequence libraries, sediment radiocarbon age data, sedimentation rates, and hydrocarbons revealed that the German U-boat U-166 and the wooden-hulled sailing vessel known as the Mardi Gras Wreck, both in the Mississippi Canyon leasing area, were exposed to deposited oil during a rapid sedimentation event. Impacts to shipwreck microbiomes included a significant increase in Piscirickettsiaceae-related sequences in surface sediments, and reduced biodiversity relative to unimpacted sites. This study is the first to address the impact of the spill on shipwreck-associated microbiomes, and to explore how shipwrecks themselves influence microbiome diversity in the deep sea.

Immuno-protective role of biologically synthesized dietary selenium nanoparticles against multiple stressors in Pangasinodon hypophthalmus.

An environment friendly and sustainable approach is being emerged in the area of nanotechnology for accelerated growth and development of culturable aquatic animals hence green chemistry is gaining momentum in recent years. The present study has been carried out to delineate the effects of selenium nanoparticles (Se-NPs) on growth performance, antioxidative status and immunity of fish reared under lead (Pb) and high temperature (34 °C). Three hundred and fifteen fish were equally distributed in seven treatments in triplicates. Three isocaloric and isonitrogenous experimental diets viz. control (Se-NPs-0 mg/kg), Se-NPs at 1 mg/kg and Se-NPs at 2 mg/kg were formulated. The fish were reared under lead (Pb, 1/21st of LC50 (4 ppm)) and high temperature (34 °C) stress and fed with or without dietary Se-NPs. The effects of dietary Se-NPs were studied in terms of growth performance (Weight gain %, feed conversion ratio, protein efficiency ratio and specific growth rate), antioxidative status (catalase, superoxide dismutase, glutathione-S-transferase and glutathione peroxidase), neurotransmitter enzymes (AChE), stress biomarkers (heat shock protein 70, serum cortisol, blood glucose, vitamin C), immunological status (total protein, A/G ratio and respiratory burst activity) in Pangasinodon hypophthalmus post challenge with Aeromonas veronii biovar sobria. Results of the investigation demonstrated significant improvement of growth performance, antioxidative status, neurotransmitter enzyme activity, stress markers and more importantly enhanced immunity of the fish with dietary incorporation of Se-NPs at 1 mg/kg. In addition, post bacterial infection, the relative % survival increased and cumulative mortality % decreased in the group fed with Se-NPs at 1 mg/kg diet. Pb and high temperature treated and fed with control diet group showed devastating impact on the growth performance, antioxidative status, stress markers and immunity of the fish. Similarly, application of Se-NPs at 2 mg/kg showed poor growth performance and elevated level of oxidative stress and other stress biomarkers including other biochemical attributes. Inclusive results indicated that, Se-NPs at 1 mg/kg has capability to enhance overall performance and alleviate multiple stresses in P. hypophthalmus. Hence, Se-NPs at optimum level have ability to develop green chemistry in feed industry for better growth performance of the fish.