The objective of this study is to propose the use of specific synthetic lipid as an active substance (biocide) in the control of harmful aquatic microorganisms, such as pathogens and non-indigenous species, transported in ships' ballast water. The biocide candidate, without metal or halogen components, was produced from a sub-product of the edible oil industry, the lecithin. Laboratory assays were conducted with phytoplankton, zooplankton, and marine bacteria to evaluate the efficiency of the biocide. The study also considers specific biocide's characteristics related to environmental risks, such as chemical composition, persistence, bioaccumulation, and toxicity. Results showed that, in the first 24 h of treatment, the biocide effectively reduced the concentration of the planktonic micro-organisms to very low levels. Additionally, a preliminary risk evaluation pointed that biocide candidate has a low residual toxicity, also a low potential for persistence and bioaccumulation in the environment.

The goal of the present study was to verify the suitability of using melanomacrophage centres (MMCs) as response biomarkers of marine pollution in European anchovy, which are short-lived, migratory, small pelagic fish. This suitability was verified by analysing the MMC density and cytochrome P450 monooxygenase 1A (CYP1A) expression in livers of anchovies from four areas of southern Italy. Age 2 anchovies sampled from three areas exposed to pollutants of industrial/agricultural origin (Gulf of Gela, Mazara del Vallo and Gulf of Naples) showed liver areas occupied by MMCs and numbers of MMCs that were significantly higher than those in the anchovies from Pozzallo, which is a marine area not subjected to any source of pollution. Anti-CYP1A immunoreactivity was observed in the hepatocytes of all specimens sampled from the Gulf of Gela. These findings suggest the utility of liver MMCs as biomarkers of exposure to pollutants in this small pelagic fish.

This body of work demonstrated the levels of selected contaminants (as well as their potential sources), in mussels (Mytella guyanensis) - a known bio-indicator of pollution, along the west coast (Gulf-of-Paria) of Trinidad. The findings demonstrated that polyaromatic hydrocarbons levels in the mussels investigated were moderate to high (201.80–1200.08 μg/kg). Notably, benzo(a)pyrene levels (1.15–9.32 μg/kg) exceeded the European Union guidelines at various sites. The distribution of PAHs and trace elements in the Gulf of Paria are impacted by tidal currents and local source discharge. Significant risks were identified from toxic carcinogenic equivalent levels (3.01 to 22.37 μg/kg) and mutagenic equivalent levels (3.98 to 38.61 μg/kg). The concentration of trace elements, Zn (46.05–56.36 mg/kg) and Cd (0.46–1.17 mg/kg), exceeded both local and international guidelines at certain sites investigated. The analysis revealed a high bioavailability of the identified pollutants in the Gulf of Paria from industrial, urban and marine activities.

Natural radioactivity in the beach sand and soil was measured and evaluated in typical ecosystems of mangroves, seagrasses, and coral reefs along the coastline of Guangxi Province, China. Radioactivity in the soil was about three times higher than that in the beach sand probably due to the distinct mineral components and particle sizes. A comparison with natural radioactivity levels in the global beach sands indicated that the beach sand of Guangxi had the lowest radioactivity. Radiological parameters including radium equivalent activity (Raeq), external and internal hazard indices (Hex and Hin), representative gamma level index (Iγr), absorbed gamma dose rate (DR), and annual effective dose equivalent (AEDE) were lower than the recommended values. Our results provide baseline data on radioactivity in the beach sand and soil along the coastline of Guangxi and contribute to the database of radioactivity in the global beach sand.

This study was conducted to investigate the median lethal concentration (LC50) of copper pyrithione (CuPT) at 96-hr exposure on adult Javanese medaka (Oryzias javanicus) in revealing toxicological effects of CuPT contamination in the tropical area. Wild stock fishes were acclimatized for 14-days prior analysis. Triplicate of test tanks for seven test concentrations were placed with ten fishes each, this includes two control tanks. The behaviour of the tested fishes was manually observed through a camera. The LC50 of CuPT at 96-h was found to be 16.58mg/L. Tested fishes swam slowly in vertical movement and swam fast towards food during feeding time as the sign of stress behaviour. Meanwhile, fishes in the two control groups swam actively in a horizontal manner and no excitement during feeding time. No mortality in control groups. Results indicate CuPT to be toxic to Javanese medaka at low concentration and caused behavioural stress.

This study focuses on creating a baseline for ⁴⁰K, ²¹⁰Pb, ¹³⁷Cs, ⁹⁰Sr, ²²⁶Ra, ²²⁸Ra, ²³⁸U, ²³⁵U, ²³⁴U, ²³⁹⁺²⁴⁰Pu and ²³⁸Pu in marine sediments in the northwestern Gulf. The respective measured concentration ranges were 386–489, 32.3–48.8, 1.5–2.9, 4.53–5.42, 18.3–23.1, 18.8–23.0, 22.3–30.5, 0.99–1.33, 25.6–34.8, 0.30–0.93, and 0.0008–0.00018Bqkg⁻¹. The levels of these radionuclides are generally comparable to values reported for other marine waters in the northern hemisphere. The ¹³⁷Cs activity in the Gulf sediments offshore Kuwait is an order of magnitude lower compared to sediments from northeastern Iran. Other than that finding, no hot spots were observed in sediments adjacent to power and desalination plants, oil and gas industrial activities or wastewater treatment facilities. These data will serve as a baseline to gauge possible future inputs of radionuclides in the northern Gulf. The calculated average ratio of ²³⁵U/²³⁸U activity in the area is in agreement with the reported figure of the natural uranium ratio, suggesting the absence of depleted uranium (DU) at all the stations. The low concentration of ²³⁹⁺²⁴⁰Pu suggests that there is no significant source of plutonium except that from atmospheric fallout from weapon testing and possible dry deposition via long-range dust transport.

The aim of this study was to appraise the response of a multi-marker approach in fish species, Gobius niger and Zosterisessor ophiocephalus, in a polluted lagoon (Bizerte lagoon: MB and ML sites) and in a reference site (Ghar-El-Melh lagoon entrance) by the analysis of physiological indexes, liver histopathology and some biochemical biomarkers. The results showed liver hypertrophy in fish collected from Bizerte lagoon as well as many non-specific lesions, unlike the reference site. All Bizerte lagoon sites had the same prevalence of histopathological lesions, but the mean intensity (MI) of parasites seemed to be more sensible as an indicator of pollution levels. Indeed, parasite MI was more important in MB site that has a higher pollution level. Also, biochemical biomarkers showed an induction in Bizerte lagoon sites with some differences within sites and species. The impact of the continuous release of pollution on the biomarker's response is discussed.

The Cananéia-Iguape system is located in a coastal region of southeastern Brazil, recognized by UNESCO as an Atlantic Forest Biosphere Reserve. This system has suffered substantial environmental impacts due to the opening of an artificial channel and by past intensive mining activities. In this paper was performed the sequential chemical extraction of Cu, Pb, and Zn, on previously described sediment cores, and the statistical treatment of the data, allowing to estimate the remobilization geochemical behavior, the available content and the trend of accumulation between 1926 and 2008. The maximum available level (sum of all mobile fraction) were, in mgkg⁻¹, 18.74 for Cu, 177.55 for Pb and 123.03 for Zn. Considering its environmental availability, Pb remains a concern in the system. It was possible to recognize the anthropic contribution of Pb, being the mining activities considered the only potential source of this metal in the region.

When mixtures of aggregates and water dredged from the seabed are discharged at the surface into the adjacent water from a barge, coarse sediments sink immediately and fine sediments are suspended forming a plume. Recently, elongated plumes of fine sediment were observed by satellites near a dredging location on the continental shelf. Such plume streaks were longer in certain conditions with seasonality than expected or reported previously. Therefore, the present work studied the appearance of sediment plume with field measurements and numerical simulations and explains the seasonally varying restoring force and thicknesses of the surface mixed layer resulting from the vertical density distribution near the surface, along with mixing by hydrodynamic process. The resulting mixtures, after vertical restoring and mixing with the surroundings, determine the horizontal transport of suspended sediments. A numerical model successfully reproduced and explained the results from field measurements and satellite images along with the seasonal variations.

Natural marine snow (NMS) is defined as the “shower” of particle aggregates formed by processes that occur in the world's oceans, consisting of macroscopic aggregates of detritus, living organisms and inorganic matter. Recent studies from the Deepwater Horizon oil spill suggest that marine snow is also formed in association with oil spills and was an important factor for the transport of oil to the seabed. This review summarizes the research and literature on MS, mainly from the DWH oil spill, with a focus on the relation between the use of oil spill dispersants and the formation and fate of oil-related marine snow (ORMS). Studies are still required to determine ORMS processes at oil concentrations as relevant as possible for chemically dispersed oil.