We investigated the distributions of the artificial radionuclides ¹³⁷Cs, ²³⁹⁺²⁴⁰Pu, and ⁹⁰Sr in the various marine products around Korean Peninsula collected in 2015–2017. The activities of ¹³⁷Cs, ²³⁹⁺²⁴⁰Pu, and ⁹⁰Sr were in the ranges of 12.2–258.4 mBq kg⁻¹, 0.014–1.879 mBq kg⁻¹, and 11.3–18.3 mBq kg⁻¹, respectively. The higher ²³⁹⁺²⁴⁰Pu (a factor of 10–50) relative to fishes were observed in mollusks. ¹³⁷Cs in fishes were significantly enriched with growths. The calculated concentration factors (CFs) of ¹³⁷Cs, ²³⁹⁺²⁴⁰Pu, and ⁹⁰Sr in marine products were 7–143, 3–407, and 15–25, respectively. Overall, no noticeable artificial radioactivity was detected in marine organisms when comparing these results with previous data reported before the Fukushima nuclear accident and recommended CF values. The annual effective doses of ¹³⁷Cs, ²³⁹⁺²⁴⁰Pu, and ⁹⁰Sr by seafood consumption in South Korea were estimated to be 1.1 × 10⁻⁴, 1.6 × 10⁻⁵ and, 2.9 × 10⁻⁵ mSv yr⁻¹, respectively, which is insignificant relative to that of natural radionuclides.

Concentrations of polychlorinated dibenzo-para-dioxins and dibenzofurans (PCDD/Fs) were measured in sediment and bivalves at 25 locations along the Korean coasts during 2001–2012. Concentrations of PCDD/Fs in sediment and bivalves ranged from 0.15 to 18.9 pg TEQ/g dry weight and from 0.06 to 7.70 pg TEQ/g wet weight, respectively. Elevated PCDD/F concentrations were found at locations close to largest industrial complexes and commercial harbors. A significant decreasing trend of PCDD/Fs in sediment was associated with strong regulation of PCDD/Fs, whereas levels in bivalves did not show a decreasing trend. Octachlorinated dibenzo-p-dioxin (OCDD) was predominant in sediment, while tetrachlorinated dibenzofuran and OCDD were predominant in bivalves. Almost half (46%) of sediment samples exceeded the threshold effect level suggested by the US National Oceanic and Atmospheric Administration, implying ecotoxicological risks to benthic organisms. Our findings support the effectiveness of legislative action on PCDD/Fs for coastal environments of Korea.

Current study aimed to evaluate the microplastics abundance in the surface waters of Chabahar Bay for the first time. 21 neuston net water samples were collected from 7 stations. Microplastics were visually counted by stereomicroscope, sorted into 4 size categories, 4 shape categories, and identified by ATR-FTIR spectroscopy. Density of microplastics varied from 0.07 ± 0.03 to 1.14 ± 0.27 with an average density of 0.49 ± 0.43 particle·m−3. Microplastics were mostly found in the shape of fibers. 69% of analyzed particles were polyethylene and polypropylene. Main colors of the collected microplastics were white, blue and red. The results showed that the largest number of microplastics was found at station near populated area. Therefore, it can be concluded that, there is a pressing-need to investigate the distribution of microplastics in sediments and biota of this Bay as well as their effects on marine life and human health.

This study reports the first baselines of plastic ingestion for three fish species that are common commercial and sustenance food fish in Newfoundland. Species collections occurred between 2015 and 2016 for Atlantic cod (Gadus morhua), Atlantic salmon (Salmo salar), and capelin (Mallotus villosus). The frequency of occurrence (%FO) of plastic ingestion for both Atlantic salmon (n = 69) and capelin (n = 350) was 0%. Of the 1010 Atlantic cod individuals collected over two years, 17 individuals had ingested plastics, a %FO of 1.68%. This is the only multi-year investigation of plastic ingestion in Atlantic cod for the Northwest Atlantic, and the first baseline of plastic ingestion in Atlantic salmon and capelin on the island of Newfoundland. Considering the ecological, economic, and cultural importance of these fish species, this study is the beginning of a longitudinal study of plastic ingestion to detect any future changes in contamination levels.

Concerns are growing about the presence of fluoxetine (FLX) in environmental matrices, as well as its harmful effects on non-target organisms. FLX in aquatic ecosystems has been detected in a range varying from pg/L to ng/L, while adverse effects have been reported in several organisms inhabiting freshwater and marine environments. The present study quantifies FLX concentrations in seawater samples from Santos Bay, Brazil and assesses metabolic responses and sublethal effects on the tropical brown mussel Perna perna. Levels of ethoxyresorufin‑O‑deethylase, dibenzylfluorescein dealkylase, glutathione S-transferase, glutathione peroxidase, cholinesterase, lipoperoxidation, and DNA damage were assessed in the gills and digestive gland of these animals, and lysosomal membrane stability was also assessed in hemocytes. FLX altered phase I and II enzyme activities, caused cytogenotoxic effects, and negatively impacted the overall health of mussels exposed to environmentally relevant concentrations. These findings contribute to characterize the risks of introducing this drug into the marine environment.

PURPOSE OF REVIEW: Climate warming may bear a penalty on future ozone air quality, even in the absence of changes in anthropogenic activities. This penalty has important implications for policy-making, but its quantification involves complex meteorological, chemical, and biological processes and feedbacks that are not well understood. We examined how climate-sensitive processes may affect surface ozone, identified key knowledge gaps uncovered by recent studies, and summarized latest assessments of the climate change penalty on ozone air quality. RECENT FINDINGS: Recent analyses have challenged earlier paradigms on how climate change may affect surface ozone. The widely accepted associations of high ozone events with stagnation and heat waves require re-examination. Emission responses of natural precursors to climate warming may be significantly modulated by CO₂ levels and ecosystem feedbacks, such that the direction of emission changes cannot be robustly determined at this time. Climate variability may drive fluctuations in surface ozone, which has implications for near-term air quality management. Recent studies have generally projected a climate change penalty on ozone air quality, although the magnitudes are smaller than those projected by earlier studies. This review examined the latest understanding on the climate change penalty to surface ozone. Critical uncertainties are associated with the meteorological, chemical, and biological processes linking climate warming and ozone, and many of the known feedbacks are not yet included in models. Further research is needed to examine those processes in order to better quantify the climate change penalty on surface ozone to inform policy-making.

We investigated artificial radionuclides (²³⁹⁺²⁴⁰Pu and ¹³⁷Cs) in surface sediments and sediment cores collected from the Bohai Bay and the tidal flat of the Liaodong Bay, China. Increasing trends for ²³⁹⁺²⁴⁰Pu activities and ²⁴⁰Pu/²³⁹Pu atom ratios (˃0.18) were observed from land to sea and from north to south in the Bohai Bay. This spatial pattern implied that the scavenging process between riverine sediments and Pacific Proving Ground (PPG) source Pu transported by the currents such as Yellow Sea Warm Current had occurred in the Bohai Bay. In contrast, relatively lower ²⁴⁰Pu/²³⁹Pu atom ratios in the tidal flat of Liaodong Bay were due to the mixing process between more global out and less PPG source Pu. The riverine Pu contributions to the total global fallout Pu in the Haihe River (32.8%) were much lower than those in the Yangtze River estuary (77%–80%), indicating better soil conservation in the Haihe River Catchment.

The changes of available forms of heavy metals would affect their corresponding ecological risks in sediments. The distribution of chemical fractions of heavy metals in sediment profiles from Chunfeng Lake estuary was investigated and then a prediction model for potential ecological risk index (PMRI) was proposed to forecast the changes of ecological risks caused by the aging process of metals in sediments. The results show that the estuarine sediments were polluted by As and Cd. The proportions of available metals were generally decreased with depth, while those of the residual forms showed an opposite trend. The aging rates of Cd and As were found to be 0.21 and 0.12%/year, respectively. The PMRI model showed that the total ecological risk of metals in sediments decreased from moderate to low risk level (<150) after 25 years, while cadmium would need 47 years in contrast to the 15 years for As.

This study investigated polycyclic aromatic hydrocarbons (PAHs) and organochlorine compounds such as polychlorinated biphenyls (PCBs) and DDT-related pesticides in surface sediments of Hooghly estuary and the Sundarban mangrove wetlands. Concentrations of ∑₁₇PAH, ∑₁₈₂PCB and ∑₆DDT ranged from 15.4 to 1731, not detected (nd) to 13.5 and nd to 8.97 ng g⁻¹ dry weight, respectively. Low levels of PCBs and low to moderate concentrations of DDTs and PAHs reflected recent development in West Bengal, which was dominated by agriculture and multifarious industries in the past. Diagnostic ratios suggested that major sources of PAHs are combustion processes, DDTs are input by agriculture, antifouling paints and public health campaigns, and organochlorines are predominantly from industrial origin. Heavier PCB congeners suggest local sources and short-range transport of such chemicals. Decision makers may use these findings for managing the Hooghly River watershed in order to promote a sustainable development on the eastern coast of India.

Seagrass meadows are experiencing worldwide declines mainly because of nutrient enrichment, which always result in macroalgae bloom and consequently periodic collapse and decomposition. However, effects of macroalgae decay on the sediment organic carbon (SOC) sequestration capacity remain unknown. Depending on the macroalgae biomass in eutrophic seagrass meadows of South China Sea, we carried out a laboratory chamber experiment to investigate the sediment labile organic carbon (OC) compositions and the influencing SOC transformation enzyme activity variations of seagrass meadows in response to common macroalgae bloom species (Cladophora spp.) decomposition. Although the dehydrogenase and β-glucosidase activities were not affected by macroalgae decomposition, the macroalgae decomposition significantly elevated the salt-extractable carbon (SEC) content, SEC/SOC, levels of invertase and polyphenol oxidase activities, and the CO₂ release. Overall, this study indicates that macroalgae decomposition stimulates the SOC transformation, and therefore, it is not benefit for SOC sequestration within seagrass meadows of the South China Sea.