With the use of an in situ and static method for gamma-ray measurements, levels of radioactive cesium 137 on shallow rugged reefs which lie between 37.3° N and 37.4° N, from the coastline of Fukushima to 141.06° E, at a depth of around 10 m were surveyed for the first time from May 2016 to December 2017. To confirm the contact between the detector and a surface of rock, we used a fact that potassium containing minerals are abundant and uniformly distributed in the area, and thus the strength of the photoelectric peak of natural radioactive potassium 40 is nearly constant over the area. We have found that the levels of radioactive cesium 137 varied from point to point within a range from 1 × 10⁴ Bq/m² to 6 × 10⁴ Bq/m².

Persistent organic pollutants (POPs) were analyzed in eighteen blubber samples biopsied from fin whales (Balaenoptera physalus) during the feeding season near the Antarctic Peninsula in the summer of 2013. POP content (in ng g⁻¹ lipid weight) ranged from 46.4 to 708 for polychlorinated biphenyls (∑PCBs), 6.77 to 123 for hexachlorobenzene (HCB), 10.1 to 489 for dichlorodiphenyltrichloroethane and derivatives (∑DDTs), 5.38 to 52.8 for hexachlorocyclohexanes (∑HCH) and <0.40 to 2.54 for polybrominated diphenyl ethers (∑PBDEs). The presence of those compounds in Southern Ocean fin whales is related to long-range transport and their diet based mainly on euphausiids (krill). Their contents were much lower compared to the same species in other locations, especially in the Northern Hemisphere, presumably due to differences in trophic position and the proximity of POP sources and contamination of prey items.

The extent of the Earth’s surface burned annually by fires is affected by a number of drivers, including but not limited to climate. Other important drivers include the amount and type of vegetation (fuel) available and human impacts, including fire suppression, ignition, and conversion of burnable land to crops. Prior to the evolution of hominids, area burned was dictated by climate via direct influences on vegetation, aridity, and lightning. In the future, warming will be accompanied by changes in distribution, frequency, intensity, and timing of precipitation that may promote or suppress fire activity depending on location. Where area burned increases, fire may become self-regulating by reducing fuel availability. The effects of climate change on fire regimes will be strongly modulated by humans in many areas. Here, we use a systems approach to outline major drivers of changes in area burned. Due to the array of interacting drivers working in concert with climate’s influence on burned area, and uncertainty in the direction and magnitude of changes in these drivers, there is very high uncertainty for much of the globe regarding how fire activity and accompanying smoke emissions will change in the coming decades.

In order to estimate the possible effects of existing ballast tank sediment management routine in ports the respective legal framework from different states was examined and the operational modes of selected Adriatic shipyards was analysed. The goal was to determine if the States' administration and ports' management are aware of risks which sediments pose to human health and environment due to possible presence of harmful aquatic organisms and pathogens (HAOP) or high concentrations of heavy metals. The analysis revealed that sediments from ballast tanks after being collected, are subject to the same handling procedure as any other waste material generated during ships' repair and maintenance. In addition, measures preventing sediment drainage into the sea or procedures for analyzing the presence of heavy metals or toxics have not been identified. The paper proposes the procedures ensuring the more advanced level of protection from HAOP and potentially toxic substances from ballast sediment.

Active acoustic sensors are widely used in oceanographic and environmental studies. Although many have nominal operating frequencies above the range of marine mammal hearing, they can produce out-of-band sound that may be audible to marine mammals. Acoustic emissions from four active acoustic transducers were characterized and compared to marine mammal hearing thresholds. All four transducers had nominal operating frequencies above the reported upper limit of marine mammal hearing, but produced measurable sound below 160 kHz. A spatial map of the acoustic emissions of each sonar is used to evaluate potential effects on marine mammal hearing when the transducer is continuously operated from a stationary platform. Based on the cumulative sound exposure level metric, the acoustic emissions from the transducers are unlikely to cause temporary threshold shifts in marine mammals, but could affect animal behavior. The extent of audibility is estimated to be, at most, on the order of 100 m.

This is the first study on polychlorinated biphenyls (PCBs) in fish from the Cau Hai lagoon, a part of the largest coastal lagoon in Southeast Asia. Seven selected PCB congeners and organochlorine pesticides in sediments and edible fish tissues were quantified by GC–MS. The sum of ICES-7 PCB and DDTs concentrations in fish species consumed regularly and of economic value were in ranges 26–43 ng g−1 lw and 182–277 ng g−1 lw, respectively. The ratio between the parent DDT compound and the sum of metabolites, DDE and DDD, was most of the time smaller than 1, suggesting primarily an historical contamination of the lagoon. An agglomerative hierarchical clustering indicates sites located in the north-western part of the Cau Hai lagoon were characterized by above-average concentrations of DDE and DDT. Comparing to previous data, a large decrease in ∑DDT residues can be seen over the past 20 years.

Concentrations of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) were determined in surface sediment from five estuaries of central coasts of Vietnam to understand the spatial distributions and seasonal variations. The contamination pattern was in the order: PCBs (9.72–3730 ng g⁻¹ dry wt.) > PBDEs (11.8–311 ng g⁻¹ dry wt.) > DDTs (0.462–26.7 ng g⁻¹ dry wt.) > HCHs (0.491–22.6 ng g⁻¹ dry wt.) > endosulfan compounds (0.196–19.4 ng g⁻¹ dry wt.). DDTs and HCHs showed a little geographical variation, whereas PCBs and PBDEs exhibited clearer spatial distribution trend. Elevated concentrations of PCBs and PBDEs were detected in some sites in Nghe An and Quang Binh Province, which could be related to the human activities such as tourism, transportation, and domestic consumption. Seasonal variations of DDTs and HCHs were observed, showing higher residues in rainy seasons.

Pulau Redang and Pulau Tioman have experienced huge tourism growth over the last two decades, but minimal sewage treatment may threaten the resilience of their coral reefs. This study uses stable isotope techniques to identify suitable bioindicators of sewage nutrients (δ¹⁵N) at these islands by measuring macroalgae (Lobophora spp.), gastropods (Drupella spp.), scleractinian coral (Acropora spp.), and leather coral (Sinularia spp.). At tourist hubs using seepage septic tank systems, enrichment of Acropora δ¹⁵N (Redang, +0.7‰) and Sinularia δ¹⁵N (Tioman, +0.4‰) compared to pristine background levels indicate enhanced sewage nutrient discharge. Carbon isotopes and survey data suggest that sedimentation did not confound these δ¹⁵N trends. Potential damaging effects of sewage discharge on the coral reef communities at both islands are highlighted by strong correlations between Acropora δ¹⁵N and regional variation in coral reef community structure, and exclusive occurrence of degraded reefs at regions of high sewage influence.

Methods standardisation in microplastics research is needed. Apart from reagent-dependent effects on microplastics, varying target particle sizes can hinder result comparison between studies. Human health concerns warrant recovery of small microplastics. We compared existing techniques using hydrogen peroxide, Proteinase-K, Trypsin and potassium hydroxide to digest bivalve tissue. Filterability, digestion efficacy, recoverability of microplastics and subsequent polymer identification using Raman spectroscopy and a matching software were assessed. Only KOH allowed filtration at ≤25 μm. When adding a neutralisation step prior to filtration, KOH digestates were filterable using 1.2-μm filters. Digestion efficacies were >95.0% for oysters, but lower for clams. KOH destroyed rayon at 60 °C but not at 40 °C. Acrylic fibre identification was affected due to changes in Raman spectra peaks. Despite those effects, we recommend KOH as the most viable extraction method for exposure risk studies, due to microplastics recovery from bivalve tissues of single-digit micrometre size.

The global plastic economy demands to reduce the flow of plastic into oceans and promote remedial actions for already accumulated seafloor litter. In this perspective, baseline levels of contamination and tools for dating litter items in order to assess the efficacy of those actions, are thus needed. In this note we discuss the utility of introducing the acquisition of shelf-life and labels features from litter items into already established standardized protocols such as the one proposed by MEDiterranean International Trawl Survey (MEDITS). Our investigation was conducted on 612 high resolution images of litter items collected in each haul, which was retrieved during 6 years of surveys (2013–2018) around Sardinian sea (central western Mediterranean). While for the majority of items (89%) expiration date or labels were not present or legible, over 50% of dated items were likely dumped at sea from a period <5 years. In this perspective, this sort of data could represent a useful tool for monitoring the effectiveness of input reduction actions that implicitly rely on the gradual reduction of recently dumped items.