Floods caused by heavy rain carry significant amounts of pollutants into marine environments. This study evaluates the effect of multiple floods that occurred in the northeastern Mediterranean region in Turkey between December 2016 and January 2017 on the microplastic pollution in the Mersin Bay. Sampling was repeated in four different stations both before and after the flood period, and it was determined that in the four stations, there was an average of 539,189 MPs/km² before the flood, and 7,699,716 MPs/km² afterwards, representing a 14-fold increase. Fourteen different polymer types were detected in an ATR FT-IR analysis, eight of which were not found in samples collected before the floods. The most common polymer type was identified as polyethylene both pre- and post-flood. The mean particle size, which was 2.37 mm in the pre-flood period, decreased to 1.13 mm in the post-flood period. A hydrodynamic modeling study was implemented to hindcast the current structure and the spatial and temporal distributions of microplastics within the study area. In conclusion, heavy rain and severe floods can dramatically increase the microplastic levels in the sea.

IMO’s Anti-Fouling Systems convention banned the use of organotin-based antifouling systems in 2008 as the ultimate effort to stop tributyltin (TBT) inputs into the marine environment. One of the hazardous effects of TBT is imposex (the superimposition of male sexual characters onto gastropod females), a phenomenon that may cause female sterility and the gastropod populations decline. Despite previous European Union legislation had already been shown effective in reducing the imposex levels along the Portuguese coast, this study intends to confirm these decreasing trends after 2008 and describe the global evolution in the last 15 years. Imposex levels were assessed in two bioindicators – the dog-whelk Nucella lapillus and the netted-whelk Nassarius reticulatus (Gastropoda, Prosobranchia) – in 2011 and 2014, and the results were compared with previous years. Both species showed progressive decreasing trends in imposex levels over the last 15 years; median values of the vas deferens sequence index (VDSI) fell from 3.96 to 0.78 in N. lapillus and from 3.39 to 0.29 in N. reticulatus. The temporal/spatial evolution of imposex suggests an apparent shift of TBT hotspots, being now restricted to fishing ports and marinas in detriment of large commercial harbours where TBT levels fell rapidly. Butyltins were measured in the whole tissues of N. lapillus females collected in 2014: monobutyltin (MBT) varied from < DL (detection limit: 1 ng Sn/g) to 13 ng Sn/g dw, dibutyltin (DBT) from 2.2 to 27 ng Sn/g dw and TBT from 1.5 to 55 ng Sn/g dw. Although TBT body burden has declined over time, the butyltin degradation index ([MBT]+[DBT])/[TBT] exhibited values < 1 in c. a. 90% of the sites assessed, suggesting that recent TBT inputs are still widespread in the Portuguese coast eventually due to illegal use of TBT antifouling systems and TBT desorption from sediments.

The tidal flats near Sinduri beach in Taean, Korea, have been severely contaminated by heavy crude oils due to the Korea's worst oil spill accident, say the Hebei Spirit Oil Spill, in 2007. Crude oil compounds, including polycyclic aromatic hydrocarbons (PAHs), pose significant environmental damages due to their wide distribution, persistence, high toxicity, mutagenicity, and carcinogenicity. Microbial community of Sinduri beach sediments samples was analyzed by metagenomic data with 16S rRNA gene amplicons. Three phyla (Proteobacteria, Firmicutes, and Bacteroidetes) accounted for approximately ≥93.0% of the total phyla based on metagenomic analysis. Proteobacteria was the dominant phylum in Sinduri beach sediments. Cultivable bacteria were isolated from PAH-enriched cultures, and bacterial diversity was investigated through performing culture characterization followed by molecular biology methods. Sixty-seven isolates were obtained, comprising representatives of Actinobacteria, Firmicutes, α- and γ-Proteobacteria, and Bacteroidetes. PAH catabolism genes, such as naphthalene dioxygenase (NDO) and aromatic ring hydroxylating dioxygenase (ARHDO), were used as genetic markers to assess biodegradation of PAHs in the cultivable bacteria. The ability to degrade PAHs was demonstrated by monitoring the removal of PAHs using a gas chromatography mass spectrometer. Overall, various PAH-degrading bacteria were widely present in Sinduri beach sediments and generally reflected the restored microbial community. Among them, Cobetia marina, Rhodococcus soli, and Pseudoalteromonas agarivorans were found to be significant in degradation of PAHs. This large collection of PAH-degrading strains represents a valuable resource for studies investigating mechanisms of PAH degradation and bioremediation in oil contaminated coastal environment, elsewhere.

Although the Korean tidal flats in the Yellow Sea have been highlighted as a typical macrotidal system, so far, there have been no measurements of the sediment erodibility and critical shear stress for erosion (τce). Using the Gust erosion microcosm system, a series of field experiments has been conducted in the Ganghwa tidal flat to investigate quantitatively the effects of biogenic materials on the erodibility of intertidal cohesive sediments. Four representative sediment cores with different surficial conditions were analyzed to estimate the τce and eroded mass. Results show that τce of the “free” sediment bed not covered by any biogenic material on the Ganghwa tidal flat was in the range of 0.1–0.2 Pa, whereas the sediment bed partially covered by vegetation (Phragmites communis) or fecal pellets had enhanced τce up to 0.45–0.6 Pa. The physical presence of vegetation or fecal pellets contributed to protection of the sediment bed by blocking the turbulent energy. An inverse relationship between the organic matter included in the eroded mass and the applied shear stress was observed. This suggests that the organic matter enriched in a near-bed fluff layer is highly erodible, and the organic matter within the underlying sediment layer becomes depleted and less erodible with depth. Our study underlines the role of biogenic material in stabilizing the benthic sediment bed in the intertidal zone.

The concentration distributions, compositional profiles and seasonal variations of 17 perfluoroalkyl acids (PFAAs) in PM₁₀ (particles with aerodynamic diameters < 10 μm) were determined in seven coastal cities of the Bohai and Yellow Seas. The detection rates of perfluorooctanoic acid (PFOA) and short-chain components (perfluoroalkyl carboxylic acids (PFCAs) with ≤7 carbon atoms and perfluoroalkane sulfonic acids (PFSAs) with ≤5 carbon atoms) were much higher than those of other long-chain PFAA species. The annual average concentration of total PFAAs in PM₁₀ ranged from 23.6 pg/m³ to 94.5 pg/m³ for the sampling cities. The monthly mean concentrations of PFAAs in PM₁₀ in some sampling cities reached a peak value in winter, while no significant seasonal differences presented in other cities. High concentrations of PFAAs in the northern cities generally occurred during the local heating period (from November to March). Generally, the dominant components of PFAAs were PFOA and perfluorobutyric acid (PFBA). Some significantly positive correlations (p < 0.01) between the 10 dominant components were revealed in the sampling cities, which implied similar sources and fate behaviors. Based on the simulated 72-hr backward trajectory tracking of air masses, the clustering results demonstrated the sampling cities were affected mainly by the atmospheric transport in sequence from the northwest, the southwest and the open seas, and many transport trajectories of air masses passed by the local fluorine chemical manufacturers in Liaoning, Shandong, Jiangsu, and Hubei Provinces. The estimated average daily intake (ADI) corresponding to the residents in different age groups indicated insignificant contributions to PFOA and perfluorooctane sulfonate (PFOS) exposures by inhalation of PM₁₀ compared to ingestion by daily diet, while the higher ADI of PFOA than the reported levels for adults should be a concern. The calculated hazard ratios (HR) exhibited low noncancer risks by inhalation exposure to PFOA and PFOS in PM₁₀.

The gulf of Annaba, the most important touristic and economic coastal zone located in Northeast Algeria, is contaminated by several pollutants from urban, agricultural, harbor and industrial activities. Elevated levels of heavy metals were detected in a locally prevalent edible mollusk Donax trunculus (Bivalvia, Donacidae) widely used as a sentinel species for the assessment of marine pollution. The present work aims to measure the difference between two localities, one being full of different pollutants (Sidi Salem) and the other being relatively clean (El Battah) and to evaluate the ability of D. trunculus to overcome the environmental stress during a transplantation experiment by a determination of fatty acid profile, the enzymes activities and the level of metallothioneins (MTs), a biomarker of metallic contamination. Adults of D. trunculus were collected at Sidi Salem (contaminated site) and transplanted into El Battah (reference site) for 21 days in cages (60 × 60 × 60 cm with a 2 mm mesh). Biochemical analyzes were conducted at different times (0, 7, 14 and 21 days). At 0-day experiment: the rate of the fatty acids, the enzymes activities and MT levels at the site of Sidi Salem (polluted site) were significantly different from those of El Battah. During the transplantation a gradual restoration of fatty acids rates, enzymes activities and MT levels was observed. At the end of the period of transplantation, the values are comparable to those of El Battah. A two-way ANOVA (time, site) on data revealed significant effects of time and site. Overally, D. trunculus is able to induce its detoxification system and to restore relatively rapidly the status of individuals from the reference site (El Battah).

Hexabromocyclododecanes (HBCDs) are the subject of recent interest and potential risk assessment particularly in China due to its ubiquitous existence in a variety of environmental media. This paper reviews the recent studies conducted on HBCDs in different environmental media (air, soil, water, river sediment, sewage sludge, biota and daily food) in China. At the same time, human health risks via food and occupational exposure of HBCDs in production plants, expanded polystyrene (EPS) and extruded polystyrene (XPS) plants were assessed. The review reveals that HBCDs levels of air, soil, sediment, sewage sludge, biota and food presented a geographical variation in the eastern coastal regions of China. There were many factors resulting in the variation, such as sampling sites, climate and analytical method. In terms of diastereoisomer, α-HBCD and γ-HBCD were the predominant diastereoisomers in air, soil, sediment, and sewage sludge. In the water, α-HBCD and γ-HBCD shared the major proportion to the total HBCDs. However, only α-HBCD was the predominant diastereoisomer in biota. With regard to human exposure pathway to HBCDs, food was the major route for human exposure to HBCDs, especially meat. In addition, soil and road dust were also important exposure pathways. Furthermore, workers and residents, especially infants in and around waste dumping sites and industrial areas are exposed to the highest HBCDs levels among all the populations studied thus far. HBCDs posed a potential threat to the environment and human health. Therefore, risk assessment and management have an important role to play in preventing and mitigating HBCDs risks.

This study developed a lightweight air composition measuring equipment (ACME) mounted in unmanned aerial vehicles (UAVs) to measure the vertical distribution characteristics of PM₂.₅ chemical species in the micro-scale urban environment for the first time. 212 samples collected from 0 to 350 m above ground level were analyzed for water-soluble ions. The concentrations of most ions on the above ground level were higher than that on the ground surface during the sampling period. The measurements of the total ion concentrations were approximately 54 to 26% of the PM₂.₅ mass concentrations on the ground surface. The concentrations of NH₄⁺ and NO₃⁻ decreased with increases in the height from the ground, which may be related to the influence of the vehicle emissions and human activities. NO₂⁻ and SO₄²⁻ both had a peak concentration on the higher vertical altitude at night in the sea-land wind system. In the southern wind system, the emissions of sea salts, dust, and stationary pollution, might be transported by the regional prevailing airflow from the southern coastal area, were the major pollutant sources above the boundary layer. The vertical distribution of ionic concentrations and wind field provided information concerning changes in pollutant transport and source regions that affect the local air quality. The ACME mounted in UAVs is the feasible and convenient method to fast understand the vertical distributions of aerosol chemical species. It provides important information about the accumulation and diffusion effects by the boundary layer variation to aerosol characteristics, which is difficulty observed from the conventional ground-based measurements. In future, this technology is the useful application for investigating the pollutant species emitted from the smokestack and the sudden pollution accident.

Antifouling biocides in surface sediments and gastropod tissues were assessed for the first time along coastal areas of Panama under the influence of maritime activities, including one of the world's busiest shipping zones: the Panama Canal. Imposex incidence was also evaluated in five muricid species distributed along six coastal areas of Panama. This TBT-related biological alteration was detected in three species, including the first report in Purpura panama. Levels of organotins (TBT, DBT, and MBT) in gastropod tissues and surficial sediments ranged from <5 to 104 ng Sn g⁻¹ and <1–149 ng Sn g⁻¹, respectively. In addition, fresh TBT inputs were observed in areas considered as moderate to highly contaminated mainly by inputs from fishing and leisure boats. Regarding booster biocides, TCMTB and dichlofluanid were not detected in any sample, while irgarol 1051, diuron and DCOIT levels ranged from <0.08 to 2.8 ng g⁻¹, <0.75–14.1 ng g⁻¹, and <0.38–81.6 ng g⁻¹, respectively. The highest level of TBT (149 ng Sn g⁻¹) and irgarol 1051 (2.8 ng g⁻¹), as well as relevant level of DCOIT (5.7 ng g⁻¹), were detected in a marina used by recreational boats. Additionally, relatively high diuron values (14.1 ng g⁻¹) were also detected in the Panama Canal associate to a commercial port. DCOIT concentrations were associated with the presence of antifouling paint particles in sediments obtained nearby shipyard or boat maintenance sites. The highest levels of TBT, irgarol 1051, and diuron exceeded international sediment quality guidelines indicating that toxic effects could be expected in coastal areas of Panama. Thus, the simultaneous impacts produced by new and old generations of antifouling paints highlight a serious environmental issue in Panamanian coastal areas.

Five Descriptors (D) of Marine Strategy Framework Directive (MSFD): marine litter (D10), non-indigenous species (D2) and organic and inorganic pollutants (D8), were estimated in a coastal area of GSA 16 (Augusta harbour, Central Mediterranean Sea) in order to study their effects on the biodiversity (D1) of the benthic community D6) and to improve data for the MSFD. Investigation of plastic debris had led to the identification of 38 fragments divided into four categories, among which microplastics resulted as the most abundant. Six non-indigenous species, belonging to Polychaeta (Kirkegaardia dorsobranchialis, Notomastus aberans, Pista unibranchia, Pseudonereis anomala, Branchiomma bairdi) and Mollusca (Brachidontes pharaonis) were found. Biodiversity and benthic indices suggested a generalised, slightly disturbed ecological status. Anthracene, Zinc and Chrome were the most abundant chemical compounds in analysed sediments. Significant correlations were found between the abundance of trace elements vs biotic indices and between plastic debris vs biodiversity and benthic indices. This study represents the first report about the abundance of plastic debris and its relationship to contaminants and infauna in Augusta harbour. Our results can provide useful information for national and international laws and directives.