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The microplastics in the surface seawater at 23 fixed points in the southwestern waters of Jeju Island were analyzed to conduct a study on the distribution characteristics of microplastics. The abundance of microplastics was shown to be 0.17 ~ 1.37 (average 0.46) n/L, the materials were mainly PP and PE, and the shape of fragments was dominant in the 0.02–0.3 mm group in terms of sizes and shapes. Alkyd and polyester were dominant in the shape of fibers in the 1.0–5.0 mm group. The correlations between the abundance of microplastics, water temperatures, and salinity were compared and as a result, water temperatures, PE, and the 0.02–0.3 mm size group, and the shape of fragments showed negative correlations. Therefore, it is judged that the for PE, which are in the form of 0.02 ~ 0.3 mm fragments to flow into the study area through the Yellow Sea coastal current and the Korean coastal current that show tendencies of relatively low water temperatures. However, since salinity and PP and polyester showed positive correlations, it is judged the possibility for polyester, which are in the form of 1.0 ~ 5.0 mm fibers, to flow into the study area through the Taiwan warm current and Tsushima warm current. In conclusion, it could be judged that in the complex open waters where continental and oceanic waters intersect, the sources of inflow may be different depending on the components of microplastics.

Current mass balances of C, N, and P were estimated using a model (Fluxin = Fluxout + ΔFlux) from Gamak Bay, Korea, in August 2017, where eutrophication and reducing conditions are prevalent. To examine the current fluxes of particulate organic carbon (POC), nitrogen (PON), and phosphorus (POP), sinking and re-floating sediment traps were deployed, a sediment oxygen demand (SOD) chamber experiment and ex-situ nutrient incubation experiment were conducted, and Fick’s first law of diffusion was applied. The principal component analysis and cluster analysis were performed to identify the three groups of water masses based on the characteristics of the bay, including the effects of the reducing environment due to the anoxic water mass using 14 bottom water quality parameters. In the reducing environment (sampling point GA4), the SOD20 flux was 3047.2 mg O2/m2/d. Additionally, the net sinking POC flux was 861.0 mg C/m2/d, while 131.8% of the net sinking POC flux (1134.5 mg C/m2/d) was removed toward the overlying water. This indicates that the organic matter that had been deposited was decomposed as a flux of 273.6 mg C/m2/d. The net sinking PON flux was 187.9 mg N/m2/d, whereas 15.8% of the net sinking PON flux was eluted, and 84.2% remained in the surface sediments. The dissolved inorganic nitrogen (DIN) elution flux from the surface sediments consisted of NH4+ elution (33.7 mg N/m2/d) and NOx− elution (−4.1 mg N/m2/d) fluxes. Despite the net sinking POP flux being 26.0 mg P/m2/d, the 47.7 mg P/m2/d of DIP elution flux (179.5% of the net sinking POP flux) was eluted to the overlying water. Similar to C mass balance, the additional elution flux occurred. Therefore, severe eutrophication (16.5 of the Okaichi eutrophication index) with the lowest N:P ratio (2.6) in GA4 was noted. This indicates that not only the freshly exported organic matter to the surface sediments but also the biochemical processes under anoxic conditions played an essential role as a remarkable nutrient source–particularly P–for eutrophication in Gamak Bay, Korea.

This study determined the PAH contamination variations in the subtidal surface sediment with oil fingerprinting in the Wu Yi San oil spill in Yeosu, Korea, in January 2014. The ∑16 PAHs and ∑alkyl PAHs were investigated in surface sediment and seawater 1 month after the oil spill for 1 year at 3-month intervals in the accident (St. A-F) and adjacent areas (St. 1-20). The averaged ∑16 PAHs and ∑alkyl PAH concentration in the five samplings were 42.2–171.7 ng/g and 211.5–221.8 ng/g, respectively. Comparing the PAH levels in St.E and St.17 indicated a decreased tendency, from 357.9 to 31.1 ng/g dw. in ∑16 PAHs, and from 1900.9 to 211.5 ng/g dw. in ∑alkyl PAHs. The PAHs were not statically correlated between surface sediment and seawater (p > 0.05), implying that the fate of PAHs was rapidly dispersed toward adjacent coasts and beaches. Pyrogenic origin was predominant in 16 PAHs, and petrogenic origin in alkylated PAHs. Notably, C2-D/C2-P and C3-D/C3-P ratios in the accident area during the first sampling were similar to accident oil, but the similarity was not shown in other samplings. Only the C2-naphthalene (St.A), C1-phenanthrene (St.A and St.B), and C2-phenanthrene (the entire accident area points) concentrations were higher than the ERL SQG.

The removal of Hg from solid waste plays a key role in environmental protection. In this study, a fast, simple, and effective method for the removal of Hg by acid extraction, using a combination of vortex agitation and ultrasonic irradiation along with hydrobromic acid (HBr), was established using Hg-containing solid wastes. The optimal durations of vortex agitation and ultrasonic irradiation with 48% v/v of HBr were 5 and 6 min, respectively, and total Hg (T-Hg) extraction was achieved within 21 min. The proposed method was validated using the Certified Reference Material (CRM) ERM CC580 (estuarine sediment) and CRM NMIJ 7302-a (marine sediment). Under the optimized conditions, the efficiency rates of T-Hg extraction in both CRMs were 99.5% and 94.2%, with repeatabilities of 3.21% RSD and 2.31% RSD, respectively. The proposed extraction method can also be used for the remediation of Hg in other environmental matrices.

Mercury (Hg), cadmium (Cd), and lead (Pb) concentrations in marketed cigarettes from South Korea, Vietnam, Japan, Indonesia, Taiwan, Thailand, the United Kingdom (UK), Belgium, Italy, Finland, and France were investigated. The cigarettes from Vietnam and Thailand had the highest trend of Hg. Meanwhile, Cd was found higher in cigarettes from Thailand, the UK, and Belgium. Pb concentrations in cigarettes from Belgium, the UK, and Korea were higher than others. The average of these heavy metals concentrated in cigarettes was in the order of Pb > Cd > Hg. Furthermore, the contents of these heavy metals in cigarette leaves were much higher than in filter and rolling paper. There was a significant positive correlation between Hg and Cd, but no correlation between Cd and Pb and between Hg and Pb. Significant positive correlations of nicotine with Hg and Cd but not Pb in the cigarette were observed. Activated carbon filters (Ce-C) absorb Cd and Pb from cigarette leaves and rolling paper indicated a higher trapping trend than cellulose acetate filter without activated carbon (Ce). The trapping ratios of Ce-C (Cd: 5.53%, Pb:5.41%) were higher than Ce (Cd:3.09%, Pb:5.49%). On the other hand, Hg had lower absorption by both types of filters (Ce:0.15%, Ce-C:0.02%). This revealed that Hg, Cd and Pb absorption ability by both filters was relatively lower to the total concentration of these metals in tobacco leaves and rolling paper. The concern was that the higher concentrations of metals such as Hg, Cd and Pb in cigarettes might exist in mainstream smoke.

Frequent discharge of mercury waste from artisanal and small-scale gold mining (ASGM) facilities into nearby farms may contaminate foodstuffs and the entire farms. High contamination levels may result in ecological risks to the soil, plants, animals, humans, and the entire farm ecosystem. This original research is the first study within the catchment areas that describes the effects of mercury waste on the entire farm ecosystem. In this study, the contamination levels and the associated ecological risks of farmland soils, plantains, and cassavas from farms sited near ASGM facilities in four communities around Obuasi, Ghana, were evaluated using the Hakanson (1980) model. Results showed that all samples except for the edible parts of plantains from Tweapease, Nyamebekyere, and Ahansonyewodea and plantain peels from Nyamebekyere and Ahansonyewodea were contaminated and may pose moderate to very high ecological risks. All farms were also contaminated and may pose considerable to very high ecological risks. The farms at Odumase were the highest contaminated with degree of contamination (C

Urban dust has been contaminated with toxic heavy metals from various diffused sources. On August 28, 2019, the compact fluorescence lamp (CFL) factory that generates light for Rang Dong Light Source and Vacuum Flask in Hanoi City in Vietnam was accidentally fired. The assessment for Hg contamination and its human health impact 2 months after the incident was conducted in autumn 2019. The heavy Hg pollution is still found near CFL. Additionally, localized Hg pollution by air and wind direction was identified at sites in the northeast direction from CFL. Namely, in the area located downstream of the southwest monsoon wind, Hg had a trend higher than other directions. The hazard quotient (HQ) and the hazard index (HI) were evaluated by four routes of Hg exposure pathways. The HI values for children and adults in the most polluted site (Site 15) were 0.968 and 0.468, respectively. This meant that children who lived around this site and commuted to schools were the most at risk regarding the potential adverse health effects of Hg in street dust around the polluted areas. This study also showed that Hg levels were affected by wind direction and that the higher Hg levels in the most polluted sites resulted from the wind flow to the sites. This study revealed that street dust may be a useful tool for the assessment of human and environmental health.