Spatial gradients of polychlorinated biphenyls (PCBs) and organochlorine pesticides were examined in the young-of-the-year (YOY) bluefish (Pomatomus saltatrix) in the vicinity of a PCB Superfund Site in New Bedford Harbor, Massachusetts, and in the adjacent waters. PCB concentrations in bluefish varied between different locations, and also among fish from a given location. A generally decreasing gradient in PCB concentrations was evident as the bluefish were collected away from the Superfund Site. The average sum of PCB concentrations were highest for bluefish collected in the Upper Harbor between Interstate-195 Bridge and Coggeshall Street Bridge (Upper Harbor), followed by bluefish in Lower Harbor from north of Popes Island Bridge (Lower Harbor), and bluefish from Outer Harbor south of Hurricane Barrier (Outer Harbor). The levels of PCBs in bluefish from Clarks Cove and PCBs in bluefish from Buzzards Bay were similar and lowest among all bluefish specimens analyzed in the present study. Pesticide concentrations were about one order of magnitude or lower than the PCB concentrations, and the gradient of pesticide concentrations generally followed the gradient of PCB concentrations. Some of the commonly detected pesticides in the order of decreasing concentrations included DDTs and metabolites, heptachlor epoxide, endosulfan sulfate, and α-chlordane. Distribution of PCBs and organochlorine pesticides were examined in the tissues of YOY bluefish from Clarks Cove. PCBs and lipids in the brain samples of YOY bluefish were generally numerically greater than PCBs in the liver samples, but these differences were not statistically significant. PCBs and lipids in hypaxial muscle samples were numerically greater than PCBs in epaxial muscle samples, although these two groups of tissues were not statistically different. Despite the higher susceptibility of lighter PCB homologs to geophysical and biogeochemical weathering processes, the relative dominance of lighter homologs in the Upper Harbor and Lower Harbor samples suggested ongoing or recent sources of these lighter PCBs, particularly Aroclor 1242 and Aroclor 1016 in this area. The presence of heavier homologs in the Upper Harbor and Lower Harbor bluefish samples could be attributed to Aroclor 1252 and Aroclor 1254 that were being used in relatively smaller quantities in the manufacture of electrical components in addition to Aroclor 1242 and Aroclor 1016. The concentration of heavier PCB homologs appears to increase in YOY bluefish the further away from the PCB Superfund Site in the Acushnet Estuary the samples were collected. Principal component analyses of PCB 153 normalized concentrations of the individual PCB congeners resulted in two general groupings; a relatively tight group comprised of YOY bluefish from Upper Harbor, Lower Harbor, and Outer Harbor, and a rather loose and more dispersed group comprised of Buzzards Bay bluefish and the tissue samples of bluefish from Clarks Cove. Principal component analyses of major pesticides suggested close groupings of bluefish from Clarks Cove and bluefish from Buzzards Bay. Pesticides in bluefish from Upper Harbor, Lower Harbor, and Outer Harbor formed a loose group, with some bluefish from these locations populating close to Clarks Cove and Buzzards Bay bluefish. Although PCBs have been implicated in various behavioral and health effects in the experimental and field studies, the deleterious effects of chronic exposure to high concentrations of PCBs and the potential for recruitment of New Bedford Harbor YOY bluefish population to the adult stock remains obscure. Adaptive or evolutionary resistance to contaminants have been documented in resident species in some highly contaminated estuaries, however similar responses have not been investigated in the migratory species like bluefish. The results of the present study provide a reference baseline for YOY bluefish for “before-and-after” comparative studies and other toxicological studies for the New Bedford Harbor Superfund Site that is currently being remediated.

Understanding the ecology of sediments that are contaminated with heavy metals is critical for bioremediating these sediments, which has become a public concern over the course of the development of modern industry. To investigate the bacterial community composition of sediments that are contaminated with heavy metals in the Xiangjiang River, a total of four sediment samples contaminated with multiple heavy metals were obtained, and a culture-independent molecular analysis, polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP), was performed. The results revealed that heavy metal pollution affected the sediment microbial community diversity, and the greatest species diversity appeared in the moderately polluted sediment X sample. The dominant family in these sediments includes α-Proteobacteria, β-Proteobacteria and Firmicutes. Moreover, α-Proteobacteria was significantly increased with increases in heavy metal. A redundancy analysis (RDA) also confirmed this phenomenon.

The exponential decay of the amount of new litter on Wadahama Beach, Nii-jima Island, Japan revealed by 20-month mark-recapture experiments demonstrates a linear response of the beach to the input of target items. Here we show the amplitude and phase characteristics of the beach as a time-invariant linear input/output system and discuss the hydrodynamic and geomorphological factors that would determine the characteristics with the aid of a diffusion equation. The characteristics are fully determined by the residence time of the items (τr=209days) and can be described as functions of the ratio of τr to the period of input variability. The decay is reproduced well by the analytical solution of the equation with a constant diffusion coefficient (D), whose order was estimated by τr and the backshore width. Generally, D would depend on hydrodynamical statistics and beach geomorphology as well as the dimensions and density of the items.

This paper reanalyzes data from an earlier study that used effluents from oiled-gravel columns to assess the toxicity of aqueous fractions of weathered crude oil to Pacific herring embryos and larvae. This reanalysis has implications for future similar investigations, including the observance of two distinct dose–response curves for lethal and sublethal endpoints for different exposures in the same experiment, and the need to consider both potency and slope of dose–response curves for components of a toxicant mixture that shows potentially different toxicity mechanisms/causation. Contrary to conclusions of the original study, the aqueous concentration data cannot support the hypothesis that polycyclic aromatic hydrocarbons (PAHs) were the sole cause of toxicity and that oil toxicity increased with weathering. Confounding issues associated with the oiled gravel columns include changes in the concentration and composition of chemicals in exposure water, which interfere with the production of reliable and reproducible results relevant to the field.

This study evaluated the efficiency of Avicennia schaueriana in the implementation of phytoremediation compared with intrinsic bioremediation in mangrove sediments contaminated by total petroleum hydrocarbons (TPHs). The experiment was conducted for 3months at a pilot scale under conditions similar to a mangrove: the dynamics of the tides were simulated, and physical, chemical, microbiological and biogeochemical parameters were monitored. After the 90days, it was found that the phytoremediation was more efficient in the degradation of the TPHs compared to bioremediation, reducing the initial concentration of 32.2–4.2mg/g. A. schaueriana was also more efficient in mediating the degradation of different fractions of hydrocarbons, achieving a removal efficiency of 87%. The microbiological results consisted of a higher growth in the model with the plants, demonstrating the phytostimulation ability of the plants. Finally, the experiment showed that phytoremediation is a promising alternative in mangrove impacted by oil.

Mercury (Hg), selenium (Se) and nitrogen (δ15N) stable isotope were assessed in a tropical food web of Rio de Janeiro’s north coast. Isotopic data on muscle suggest a difference related to this parameter along the food web; where top-predators (cetacean and voracious fish) displayed heavier δ15N over the entire food web. Both top-predators presented similar δ15N values. Cetacean displayed higher Hg and lower Se than voracious fish. Five trophic positions (TP) were found in relation to primary consumer as baseline, ranging from 2.0 to 4.0. Positive relationships were found between trace-element and δ15N. The slope of regression equations (0.11 for Se and 0.21 for Hg) and food web magnification factors (2.4 for Se and 5.4 for Hg) showed that Hg presented higher rate of increase over the food web. Simultaneous measurements of trace-elements and ecological tracers emphasize the importance of TP into the trophic structure and distribution of Hg and Se throughout the food web.

Plastic marine debris is presently widely recognised as an important environmental pollutant. Such debris is reported in every habitat of the oceans, from urban tourist beaches to remote islands and from the ocean surface to submarine canyons, and is found buried and deposited on sandy and cobble beaches. Plastic marine debris varies from micrometres to several metres in length and is potentially ingested by animals of every level of the marine food web. Here, we show that synthetic polymers are present in subsurface plankton samples around Saint Peter and Saint Paul Archipelago in the Equatorial Atlantic Ocean. To explain the distribution of microplastics around the Archipelago, we proposed a generalised linear model (GLM) that suggests the existence of an outward gradient of mean plastic-particle densities. Plastic items can be autochthonous or transported over large oceanic distances. One probable source is the small but persistent fishing fleet using the area.

We analyzed stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) as well as mercury (Hg) concentration in the scalp hair of Japanese who consumed whale meat and those who did not, and investigated the relationships among the δ13C and δ15N values and Hg concentration. The average δ15N and δ13C values of whale meat-eaters (10.11‰ and −18.5‰) were significantly higher than those of non-eaters (9.28‰ and −18.9‰), respectively. The average Hg concentration of whale meat-eaters (20.6μg/g) was significantly higher than that of non-eaters (2.20μg/g). Significant positive correlations were found between the δ13C and δ15N values and between the δ15N value and Hg concentration in the hair of whale meat-eaters, while the correlation between the δ15N value and Hg concentration was not statistically significant in the non-eaters. The consumption of whale meat may increase Hg concentration as well as δ15N and δ13C values in scalp hair.

Oil spills are treated as a widespread problem that poses a great threat to any ecosystem. Following first response actions, bioremediation has emerged as the best strategy for combating oil spills and can be enhanced by the following two complementary approaches: bioaugmentation and biostimulation. Bioaugmentation is one of the most controversial issues of bioremediation. Studies that compare the relative performance of bioaugmentation and biostimulation suggest that nutrient addition alone has a greater effect on oil biodegradation than the addition of microbial products because the survival and degradation ability of microbes introduced to a contaminated site are highly dependent on environmental conditions. Microbial populations grown in rich media under laboratory conditions become stressed when exposed to field conditions in which nutrient concentrations are substantially lower. There is increasing evidence that the best approach to overcoming these barriers is the use of microorganisms from the polluted area, an approach proposed as autochthonous bioaugmentation (ABA) and defined as a bioaugmentation technology that exclusively uses microorganisms indigenous to the sites (soil, sand, and water) slated for decontamination. In this work, we examined the effectiveness of strategies combining autochthonous bioaugmentation with biostimulation for successful remediation of polluted marine environments. Seawater was collected from a pristine area (Agios Onoufrios Beach, Chania) and was placed in a bioreactor with 1% v/v crude oil to facilitate the adaptation of the indigenous microorganism population. The pre-adapted consortium and the indigenous population were tested in combination with inorganic or lipophilic nutrients in the presence (or absence) of biosurfactants (rhamnolipids) during 90-day long experiments. Chemical analysis (gas chromatography–mass spectrometry) of petroleum hydrocarbons confirmed the results of previous work demonstrating that the biodegradation processes were enhanced by the addition of lipophilic fertilizers (uric acid and lecithin) in combination with biosurfactants (rhamnolipids), resulting in increased removal of petroleum hydrocarbons as well as reduction of the lag phase within 15days of treatment. Considering this outcome and examining the results, the use of biostimulation additives in combination with naturally pre-adapted hydrocarbon-degrading consortia (bioaugmentation) has proved to be an effective treatment and is a promising strategy that could be applied specifically when an oil spill approaches near a shore line and an immediate hydrocarbon degradation effort is needed.