The spatial and seasonal variation of the specific composition and community parameters (abundance, diversity, richness and evenness) of the intertidal algal assemblages was studied at four coastal sampling sites, distributed along an environmental gradient from the sewage water outfall of Mar del Plata, Buenos Aires, Argentina. Two of them were located close to the sewage outfall (<800m) (impacted area) and the two other were 8 and 9km distant (non-impacted area). The algal abundance was monthly analyzed from October 2008 to May 2009. The algal assemblages varied according to the pollution gradient in spring, summer and autumn, being autumn the season when the highest difference was observed. Ceramium uruguayense was recognized as an indicator species for the non-impacted areas, while Berkeleya sp. represented an indicator species for the sewage outfall impact. Ulva spp. did not reflect the typical pattern observed for other sewage pollution areas.

Floating litter in the estuarine system of Santos-São Vicente is common and is part of day-to-day activities of various users of the area. The objective of the present study was to carry out a quali-quantitative evaluation of the occurrence of floating litter, to infer their sources, and to identify environmental factors that are likely to control occurrence and distribution, with particular emphasis on the effects of tidal regimes. Six sampling stations were selected along the aforementioned estuary and visited monthly between July 2010 and January 2012. Floating litter was counted from a fixed sampling station. Plastics prevailed (89.64%) and their main source was domestic activities (55.41%). More litter was found during ebb spring tides, with higher concentrations obeying confluence patterns of the estuary's channels. Results indicated that occurrence can be attributed to the deficiency in basic sewage system in the area and the deliberate disposal into the estuary by the local population.

This paper presents a study on the impact of underwater gas blowouts near the ocean surface, which has a greater relevance to assess Health, Safety, and Environmental risks. In this analysis the gas flux near the surface, reduction of bulk density, and gas surfacing area are studied for different scenarios. The simulations include a matrix of scenarios for different release depths, release rates, and initial bubble size distributions. The simulations are carried out using the MEGADEEP model, for a location in East China Sea. Significant changes in bulk density and gas surface flux near the surface are observed under different release conditions, which can pose a potential threat for cleanup and rescue operations. Furthermore, the effect of hydrate formation on gas surfacing is studied for much greater release depths. The type of outcomes of this study is important to conduct prior risk assessments and contingency planning for underwater gas blowouts.

In the current study, biocompatible and biodegradable blends based on poly(vinyl alcohol) nanoparticles – PVAn mixed with either chitosan (Ch) or starch (St) – were prepared and investigated as nanoabsorbents for oil elimination from wastewater. The use of water/dimethyl sulfoxide (DMSO) as a mixed solvent is the key factor for preparing aggregated PVAn, which is further mixed with Ch or St. Nanoblends were applied as oil absorbents, and the results showed that PVAn/St possess high adsorption capacity than PVAn/Ch and PVAn. The maximum sorption capacities (qg/g) of the PVAn/Ch sorbents for hydraulic oil, kerosene, and toluene were 33.6, 73.96, and 93.1g/g, respectively. The absorbed oil could be rapidly recovered by simple mechanical squeezing and reused without any other modification. The blends showed excellent reusability and could be reused for at least 10 times with minimal losses. The current study demonstrates the application of these blends as an ideal alternative sorbent for oil spillage cleanup.

Little Penguins (Eudyptula minor) are high-trophic coastal feeders and are effective indicators of bioavailable pollutants in their foraging zones. Here, we present concentrations of metals and metalloids in blood of 157 Little Penguins, collected over three years and during three distinct seasons (breeding, moulting and non-breeding) at two locations: the urban St Kilda colony and the semi-rural colony at Phillip Island, Victoria, Australia. Penguin metal concentrations were foremostly influenced by location (St Kilda>Phillip Island for non-essential elements) and differed among years and seasons at both locations, reflecting differences in seasonal metal bioaccumulation or seasonal exposure through prey. Mean blood mercury concentrations showed an increasing annual trend and a negative correlation with flipper length at St Kilda. Notably, this study is the first to report on blood metal concentrations during the different stages of moult, showing the mechanism of non-essential metal mobilisation and detoxification.

With increasing concern over the aquatic environment in marine culture, the integrated multi-trophic aquaculture (IMTA) has received extensive attention in recent years. A three-dimensional numerical ocean model is developed to explore the negative impacts of aquaculture wastes and assess the bio-mitigation effect of IMTA systems on marine environments. Numerical results showed that the concentration of surface phytoplankton could be controlled by planting seaweed (a maximum reduction of 30%), and the percentage change in the improvement of bottom dissolved oxygen concentration increased to 35% at maximum due to the ingestion of organic wastes by sea cucumbers. Numerical simulations indicate that seaweeds need to be harvested in a timely manner for maximal absorption of nutrients, and the initial stocking density of sea cucumbers >3.9 individuals m−2 is preferred to further eliminate the organic wastes sinking down to the sea bottom.

Assessment of heavy metal bioavailability in sediments is complex because of the number of partial extraction methods available for the assessment and the general lack of certified reference materials. This study evaluates five different extraction methodologies to ascertain the relative strengths and weaknesses of each method. The results are then compared to previously published work to ascertain the most effective partial extraction technique, which was established to dilute (0.75–1M) nitric acid solutions. These results imply that single reagent; weak acid extractions provide a better assessment of potentially bioavailable metals than the chelating agents used in sequential extraction methods.

Industrial pressures suffered by estuarine zones leave a pollution record in their sediment. Thus, high concentrations of many heavy metals and some organic compounds are often found in estuarine sediment. This work aims to contribute to the enhancement of water quality management strategies in these zones by studying in detail the diffusive processes that take place between the water and sediment using a two-pronged approach: experimental practice and numerical simulation. To provide an example of the practical application of the methodologies proposed in this paper, the Suances Estuary (northern Spain) was selected as the study zone. This estuary exhibits significant historical pollution and its sediment acts as a continuous internal source of zinc, mainly due to diffusive processes derived from the concentration gradient between the interstitial water at the solid particles of the sediment and the bottom of the water column. The experimentally obtained results, based on 6 case studies, demonstrated the buffering capacity of the system and allowed the determination of the required time for the mass transfer processes to reach an equilibrium state. Furthermore, the diffusion rate of zinc was approximately modeled taking into consideration the high concentration variability observed in sediment along the entire estuary. The convergence between the modeled and the experimental results indicated the required contact time to reach an equilibrium state in a real field situation.

Pre-spill background concentrations of TPH and PAH in water samples from the Gulf of Mexico are compared with samples (over 20,000) collected during and after the Deepwater Horizon incident (13,000 stations). Samples were collected by multiple response agencies, trustees and BP and reported in the Gulf Science Data. The samples were collected from a few m to over 800km in all directions from the wellhead. During the incident, samples with the highest concentrations of hydrocarbons were collected proximal to the wellhead or in samples collected from surface slicks and dispersant use. Of the 13,172 water sample TPH concentrations reported, 84% were below 1μg/L (background). Of the 16,557 water sample PAH concentrations reported, 79% were below 0.056μg/L (the median field blank, background). The percentage of samples below background increased rapidly after the well was capped. The spatial and temporal distributions of these hydrocarbon data are presented.

Microplastics enter the environment as a result of larger plastic items breaking down (‘secondary’) and from particles originally manufactured at that size (‘primary’). Personal care products are an important contributor of secondary microplastics (typically referred to as ‘microbeads’), for example in toothpaste, facial scrubs and soaps. Consumers play an important role in influencing the demand for these products and therefore any associated environmental consequences. Hence we need to understand public perceptions in order to help reduce emissions of microplastics. This study explored awareness of plastic microbeads in personal care products in three groups: environmental activists, trainee beauticians and university students in South West England. Focus groups were run, where participants were shown the quantity of microbeads found in individual high-street personal care products. Qualitative analysis showed that while the environmentalists were originally aware of the issue, it lacked visibility and immediacy for the beauticians and students. Yet when shown the amount of plastic in a range of familiar everyday personal care products, all participants expressed considerable surprise and concern at the quantities and potential impact. Regardless of any perceived level of harm in the environment, the consensus was that their use was unnatural and unnecessary. This research could inform future communications with the public and industry as well as policy initiatives to phase out the use of microbeads.