PURPOSE OF REVIEW: Adsorbent-based microextraction is a dynamic and simple sample preparation that allows for simultaneous extraction and enrichment of targeted analytes from a sample matrix. Its versatility, efficiency, and compliance with green analysis have contributed to its popularity against conventional solid-phase extraction. This review focuses on the current state of the art, future trends in experimental design, and critical aspects of adsorbent-based microextraction techniques considered for extraction and preconcentration of different classes of micropollutants in environmental waters. RECENT FINDINGS: Despite solid-phase microextraction has shown exceptional flexibility in routine microscale extraction, the other adsorbent-based microanalytical work continues to experience an enormous increase in innovation. Discussions are focused on recent studies utilizing different modes include dispersive, magnetic, bar sorptive, membrane-protected, and thin film for introducing adsorbents in an aqueous media. Cogently, the developed micro-scale procedure using functionalized adsorbent has shown distinct advantages over conventional methods. Modifications were aimed at shortening the time for analysis, minimal waste production, and robustness over the complexity of sample matrices. Adsorbent selection is now widening from commercial materials like activated carbon to newly synthesized materials such as metal-organic framework. The final section discusses the current progress on hybrid approaches and the intended future directions to further explore and popularize the adsorbent-based microextraction. This review guides the audiences with an introductory, succinct discussion of the basic concepts of the adsorbent-based microextraction and the success story of the high-throughput real sample analysis.

PURPOSE OF REVIEW: The use of algae for remediation of toxic pollutants seems to be promising since they also provide some advantages such as the production of valuable products and their capability to capture CO₂ during the photosynthesis, which potentially decrease greenhouse gas emission. This paper reviews the evidence for highlighting the effectiveness of the use of living or non-living algal cells for treating polluted waters. RECENT FINDINGS: Removal efficiency and sorption capacity of algal non-living cells are higher than in living cells because of cell membrane disruption (leading to enhancement of intracellular pollutants binding) and the improvement of specific surface area. For the kinetic and isotherm modeling, there is no single powerful model for a wide range of pollutants and type of algae, indicating that the mechanism is quite specific depending on the type of algae, type of pollutants, and environmental conditions. The removal mechanism of pollutants by living and non-living algae can be considered as an exothermic reaction and physical sorption from many published reports. The use of non-living cells was more effective compared to living cells for a wide range of pollutants since the non-living cells performed better removal efficiency and sorption capacity as well as easy to handle. This review is useful to pave a good strategy for designing a greener technology for future environmental pollutants remediation particularly within the domain of algal-based technology.

Litter reduction in the coastal and marine environment represents a major challenge but must be prioritized to preserve biodiversity and ecosystems, as well as the goods and services that humans derive from seas and oceans. This paper reviews the available global scientific literature focusing on marine beach litter and tracks its evolution and trends by combining social network analysis and bibliometrics. The relationships and co-occurrences among authors, countries and keywords retrieved from the Scopus abstract and citation database are presented. A total of 1765 publications are analysed: the majority being journal articles. Results reveal the notable worldwide increase in scientific interest in beach litter in the last decade, as well as its multidisciplinary perspectives. This information could be beneficial for the processes that support the improvement of international efforts for beach litter monitoring, removal, and management activities.

A forensic source evaluation of polycyclic aromatic hydrocarbons (PAHs) in nearshore sediments in San Francisco Bay examined total PAH greater than ambient concentrations in sediments, and potential pyrogenic source relationships with respect to PAH compounds typically associated with point and nonpoint pyrogenic source types, including PAHs potentially associated with historical manufactured gas plant (MGP) operations. Diagnostic source ratio analysis was employed for determination of potential PAH source relationships. A two-model approach indicated distinct potential source signatures, as identified from the distributions of higher PAH concentrations in some sediments. Source characterization was aided by Polytopic Vector Analysis (PVA) and data visualization with t-Distributed Stochastic Neighbor Embedding (t-SNE). Two signatures exhibited pyrogenic character likely consistent with historical MGP sources, and one signature was related to creosote. A distinct and significant source of PAHs to the investigation area sediment consisted of ubiquitous nonpoint and potential unidentified point sources is termed “urban influence”.

PURPOSE OF REVIEW: This review is focused on the removal of chlorinated hydrocarbons (as representative of persistent pollutants) from soil by soil-washing techniques, paying special attention to the application of electrochemically assisted technologies for the treatment of the liquids and gases produced during this treatment. It considers the degree of maturity of the technologies and suggests challenges for future research. RECENT FINDINGS: Electrochemical technologies can help to improve the overall efficiency of soil washing processes in the removal of chlorinated hydrocarbons, contributing to the depletion of these hazardous species from the soil washing liquid and gaseous effluents generated during the treatment of the soil. Chlorinated hydrocarbons are a good example of persistent organic pollutants which can be found in very high concentrations in polluted soil, especially in industrial sites. Because of its fast action, soil washing can be efficient for preventing the spread of chlorinated hydrocarbons after accidental spills. Recent progress about fundamentals of this process and key parameters involved is discussed at the light of competing technologies, paying special attention to the liquid and gaseous wastes produced during this treatment, in the search of holistic approaches. Among the different alternatives proposed, electrochemical technologies are the focus of attention of many researchers and, because of that, recent progress in electrochemical technologies capable to deplete the pollutants is also discussed, within a comparison context with other competing technologies, indicating the technology readiness level of each electrochemical process and the challenges that must be overcome in order to reach full-scale applicability.

Most contemporary coral reefs live under both global (e.g. warming and acidification) and local (e.g. overfishing, pollution) stressors, which may synergistically undermine their resilience to thermal bleaching and diseases. While heavy metal toxicity in reefs has been well characterized, information on corals recovery from acute contamination is lacking. We studied for 42 days the ability of the coral Stylophora pistillata from the Gulf of Aqaba (northern Red Sea) to recover from a short (3 days) and prolonged (14 days) copper (Cu) contamination (1 μg L⁻¹), after 11 (‘Exp3/D11’) and 28 (‘Exp14/D28’) days of depuration, respectively. Cu caused a decrease in chlorophyll content after 3 days, and in net photosynthesis (Pn) after 14 and 42 days. ‘Exp14/D28’ showed successful recovery based on Pn and relative electron transport rate, as opposed to ‘Exp3/D11’. Results suggest the depuration time may be of greater importance than the exposure period to recover from such contamination.

Liquid natural gas (LNG) exploration has started off the coast of northern Mozambique, in the Rovuma Basin, East Africa. In advance of gas production, we collected in 2018 over 100 samples of surface sediments from 40 locations in the pristine and exploration areas at water depths of 5–2000 m. We have determined the levels of hydrocarbons (total hydrocarbon contents (THC) and 49 individual PAHs), heavy metals, arsenic, grain size and total organic carbon. While sediment composition varied strongly from coarse sediment to high mud contents (<63 μm), background levels of hydrocarbons and metals were found in most samples. We found anthropogenic contamination at one site in Pemba harbor. We observed no petroleum-related contamination, including the Palma area with numerous exploration wells. Elevated concentrations of barium and THC at some locations in this area are attributed to drilling activities but are not considered to be of environmental concern.

Mangrove has been destroyed and reforestation is often undertaken, but whether a regenerated forest could restore its ecological function is not clear. This study compares microbial community structure and function in sediment of the 17-years old natural regenerated mangrove forest (Y17) with the original forest (Y74). No significant differences in phospholipid fatty acid (PLFA) profiles and microbial metabolism of most carbon substrates were found between these two forests. However, activities of dehydrogenase, protease, cellulase and phosphatase were lower in Y17 than Y74, and some specific microbial functions were also different. Both forests exhibited significant seasonal differences in enzyme activities and microbial characteristics, but such difference was larger in Y17 than Y74, indicating the regenerated forest was more sensitive to season. Correspondence analysis based on PLFA profiles and enzyme activities revealed the microbial community in Y17 was comparable to Y74, suggesting sediment microbial characteristics in natural regenerated mangroves could be restored.

Nile Red is a lipophilic, metachromatic and solvatochromic dye used as an alternative or complementary method to aid identification of microplastics in routine analysis of biological samples. It was rarely used in biota since organic residues after the digestion step can be co-stained with possible overestimation of microplastics. The limits of using Nile Red in biota were investigated in marine mussels experimentally contaminated with low-density polyethylene (LDPE) microplastics. Stained particles were detected through magnified images obtained by stitching together thirty photographs of the filter surface of each sample. LDPE particles appeared yellowish and fluorescent and could be confused with certain organic residues. The smaller the fragments, the greater the difficulty in recognizing them. In particular, it was difficult to recognize LDPE particles based on their fluorescence if <180 μm in size. Regardless of the size, fluorescence of the items aids the operator in LDPE particles identification also in biota.

Microalgal communities that colonize the hulls of at-risk vessels – those which have the highest port residency times, lowest speeds, and most stationary time in water - are expected to change as a function of environmental factors during ocean voyages, but are rarely studied. The microalgal communities on the hull of an atypically operated ship, the T.S. Golden Bear, were quantified during the course of a voyage from San Francisco Bay to the South Pacific and back. Here we clearly demonstrate that microalgal communities can be highly resilient, and can survive physiologically strenuous journeys through extreme variation in salinity and temperature. A 42% reduction in microalgal biomass and a 62% reduction in algal cellular abundance indicated a community-wide negative reaction to an increase in both salinity and temperature after the ship left San Francisco Bay, CA and cruised southward to Long Beach, although in vivo cellular fluorescence capacity increased. Further reductions in biomass (36%) and cellular abundance (26%) occurred once the ship encountered high-temperature, high-salinity waters in Hawaii. A 17% reduction of cellular fluorescence capacity was also observed in Hawaii. Despite previous environmental stressors, upon return to temperate waters off Vallejo, CA, biomass increased 230%, cellular abundance remained stable, and cellular fluorescence capacity increased from 0.45 ± 0.26 to 0.60 ± 0.07. The methods used in the current research provide efficient, cost-effective procedures for analyzing microalgal (and macrofouling) communities, which can in turn aid regulators in creating such necessary thresholds for enforcement.