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• Source to estuary surveys revealed specific pollution and dam effects on river GHGs. • Pollution effects on riverine CO 2 , CH 4 , and N 2 O vary with source size and location. • Cascade weirs boost CH 4 production, offsetting CO 2 sinks in eutrophic river-estuary. • δ13C indicates wastewater-derived GHGs and temperature-enhanced CH 4 oxidation. • Basin-specific perturbations warn generalizing eutrophic river-estuary as C sinks. Large uncertainties exist regarding the combined effects of pollution and impoundment on riverine greenhouse gas (GHG) emissions. It has also been debated whether river eutrophication can transform downstream estuaries into carbon sinks. To assess human impacts on the riverine and estuarine distributions of CO 2 , CH 4 , and N 2 O, two source-to-estuary surveys along three impounded rivers in Korea were combined with multiple samplings at five or six estuarine sites. The basin-wide surveys revealed predominant pollution effects generating localized hotspots of riverine GHGs along metropolitan areas. The localized pollution effect was pronounced in the lower Han River and estuary adjacent to Seoul, while the highest GHG levels in the upper Yeongsan traversing Gwangju were not carried over into the faraway estuary. CH 4 levels were elevated across the eutrophic middle Nakdong reaches regulated by eight cascade weirs in contrast to undersaturated CO 2 indicating enhanced phytoplankton production. The levels of all three GHGs tended to be higher in the Han estuary across seasons. Higher summer-time δ13C-CH 4 values at some Nakdong and Yeongsan estuarine sites implied that temperature-enhanced CH 4 production may have been dampened by increased CH 4 oxidation. Our results suggest that the location and magnitude of pollution sources and impoundments control basin-specific longitudinal GHG distributions and estuarine carryover effects, warning against simple generalizations of eutrophic rivers and estuaries as carbon sinks. [Display omitted] [ABSTRACT FROM AUTHOR]

• BDOC measurement via DOC loss is the most accurate among available methods. • DOM optical and molecular indices can act as surrogates for BDOC and dissolved CO 2. • SUVA 254 , HIX, and terrestrial humic- and protein-like FDOM are recommended proxies. • Potentials and limitations of previously proposed DOM indices are critically discussed. Biodegradable dissolved organic carbon (BDOC) constitutes the most labile fraction of dissolved organic matter (DOM), which also functions as a source of CO 2 emissions from inland waters. However, no systematic review is available on DOM indicators of BDOC and CO 2 production potential. Optical and molecular indices can be used to track small changes in DOM composition during biodegradation. In this review, we identified four different methods for measuring BDOC together with their strengths and limitations. In addition, we discuss the potential of using documented optical indices based on absorption and fluorescence spectroscopy and molecular indices based on Fourier transform ion cyclotron mass spectrometry as proxies for estimating BDOC and biodegradation-induced CO 2 production based on previously reported relationships in the literature. Many absorbance- and fluorescence-based indices showed inconsistent relationships with BDOC depending on watershed characteristics, hydrology, and anthropogenic impacts. Nevertheless, several indices, including specific UV absorbance at 254 nm (SUVA 254), humification index (HIX), and terrestrial humic-like fluorescent DOM (FDOM) components, tended to have negative relationships with BDOC in tropical and temperate watersheds under baseflow or drought periods. Protein-like FDOM exhibited the strongest correlation with BDOC in different systems, except during storms and flood events. Despite the limited number of studies, DOM molecular indices exhibited consistent relationships with BDOC, suggesting that the relative abundance of aliphatic formulas and the molecular lability index could act as reliable proxies. The DOM optical indices explain up to 96% and 78% variability in BDOC and CO 2 , respectively; nonetheless, there were limited studies on molecular indices, which explain up to 74% variability in BDOC. Based on literature survey, we recommend several sensitive indices such as SUVA 254 , HIX, and terrestrial humic- and protein-like FDOM, which could be useful indicators of BDOC and dissolved CO 2 in inland water. Future research should incorporate a wider range of geographic regions with various land use, hydrology, and anthropogenic disturbances to develop system- or condition-specific DOM optical or molecular proxies for better prediction of BDOC and CO 2 emissions. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: An overview is provided of the potential effects of climate change on the watershed biogeochemical processes and surface water quality in mountainous watersheds of Northeast (NE) Asia that provide drinking water supplies for large populations. We address major ‘local’ issues with the case studies conducted at three watersheds along a latitudinal gradient going from northern Japan through the central Korean Peninsula and ending in southern China. Winter snow regimes and ground snowpack dynamics play a crucial role in many ecological and biogeochemical processes in the mountainous watersheds across northern Japan. A warmer winter with less snowfall, as has been projected for northern Japan, will alter the accumulation and melting of snowpacks and affect hydro-biogeochemical processes linking soil processes to surface water quality. Soils on steep hillslopes and rich in base cations have been shown to have distinct patterns in buffering acidic inputs during snowmelt. Alteration of soil microbial processes in response to more frequent freeze–thaw cycles under thinner snowpacks may increase nutrient leaching to stream waters. The amount and intensity of summer monsoon rainfalls have been increasing in Korea over recent decades. More frequent extreme rainfall events have resulted in large watershed export of sediments and nutrients from agricultural lands on steep hillslopes converted from forests. Surface water siltation caused by terrestrial export of sediments from these steep hillslopes is emerging as a new challenge for water quality management due to detrimental effects on water quality. Climatic predictions in upcoming decades for southern China include lower precipitation with large year-to-year variations. The results from a four-year intensive study at a forested watershed in Chongquing province showed that acidity and the concentrations of sulfate and nitrate in soil and surface waters were generally lower in the years with lower precipitation, suggesting year-to-year variations in precipitation as a key factor in modulating the effects of acid deposition on soil and surface water quality of this region. Results from these case studies suggest that spatially variable patterns of snow or summer precipitation associated with regional climate change across NE Asia will have significant impacts on watershed biogeochemical processes and surface water quality, in interactions with local topography, land use change, or acid deposition. [Copyright &y& Elsevier]

Abstract: HPLC–size exclusion chromatography (SEC), coupled with on-line detection of UV absorbance (UVA) and fluorescence, was used to characterize dissolved organic matter (DOM) and its interactions with dissolved metals in a forest stream, a reservoir, and an urban river. Optimization of eluent concentration (20mM) allowed separation of altogether 11 molecular size (MS) fractions when NaClO4 was used as an eluent having minimal disturbance with metals. UVA at 254nm and fulvic-like fluorescence (FFL) at 337/423 (excitation/emission) nm were detected for ‘humic’ fractions, while protein-like fluorescence (PFL) at 278/353nm was detected across the whole MS range. At all sites temporal variations in dissolved organic carbon (DOC) concentrations were well explained by changes in UVA intensity of humic fractions, while PFL intensities of a small MS fraction showed a higher correlation with DOC concentrations at the reservoir. Temporal changes in the concentrations of Al, Cr, Li, Ni, and Fe correlated with PFL intensities of small MS fractions, while variations in the concentrations of As, Co, Mn, and Pb were largely explained by UVA and PFL intensities of humic fractions. The results suggest that HPLC–SEC combined with on-line detection of UVA and PFL can be efficiently used in characterizing DOM and its interactions with metals in surface waters. [Copyright &y& Elsevier]

Abstract: The role of detrital quantity and quality in forest floor N leaching was investigated in a litter manipulation experiment at a deciduous forest under chronic N deposition. Dissolved inorganic nitrogen (DIN) comprised the bulk of nitrogen leaching from the control except a short period following autumn litterfall. The dominance of DIN was strengthened by litter exclusion, whereas the addition of glucose or fresh litter led to a small increase in dissolved organic nitrogen (DON) and either a temporary or gradual reduction in NO3 − release, respectively. Changes in soluble organic C and microbial C in the forest floor implied that increased availability of C sources might have enhanced microbial immobilization of DIN, either temporarily following glucose application or over the longer term following litter addition. The results suggest that detrital quantity and quality can play a crucial role in determining the balance between DIN and DON in N-enriched forest soils. [Copyright &y& Elsevier]

Abstract: In a competitive and globalized business environment, the need for the green products becomes stronger. To meet these trends, environmental impact assessment besides delivery, cost and quality of products should be considered as an important factor in new product development stage. In this paper, a knowledge-based approximate life cycle assessment system (KALCAS) is developed to assess the environmental impacts of product design alternatives. It aims at improving the environmental efficiency of a product using artificial neural networks, which consist of high-level product attributes and LCA results. The overall framework of a collaborative design environment involving KALCAS is proposed, using engineering solution CO™ based on the distributed object-based modeling and evaluation (DOME) system. This framework allows users to access the product data and other related information on a wide variety of application. This paper explores an approximate LCA of product design alternatives represented by solid models in a collaborative design environment. [Copyright &y& Elsevier]

The forest floor in temperate forests has become recognized for its importance in the retention of elevated inputs of dissolved inorganic nitrogen (DIN) and as a source of dissolved organic matter (DOM). A laboratory leaching experiment was conducted over the period of 98 d to examine the origin of dissolved organic carbon (DOC) and nitrogen (DON) in a deciduous forest floor, and the effect of resource availability and microbial activity on the production mechanisms involved. The experiment was composed of different types of treatments: exclusion of specific forest floor layers (no Oi, no Oe) and addition of carbon sources (glucose, cellulose, leaf, wood) and NH4NO3 (nitrogen). The cumulative amount of CO2 evolution was positively related to the availability of C sources at each treatment: glucose>leaf=wood=cellulose>control=no Oe=nitrogen>no Oi. DOC release was related to the amount of C sources but showed no clear correlation with CO2 evolution. An increase in C availability generally led to a reduction in the release of DON as well as DIN. In contrast, the amendment of NH4NO3 reduced the cumulative DOC release but enhanced the release of both DON and DIN. Fresh leaf litter was a more important DOC source than labile substrates (glucose and cellulose) as well as more stable substrates (forest floor materials and wood). Among forest floor layers, more humified horizons (Oe and Oa) were the primary source of DIN and made a similar contribution to DOM release as the Oi layer. The changes in DOM composition detected by a humification index of the leachates, in combination with a shift in the final microbial biomass C, suggested that DOM released from the soluble pools of added litter or the Oi layer contained a substantial amount of microbially processed organic matter. Our study demonstrated the importance of C availability in regulating microbial activity and immobilization of dissolved N in an N-enriched forest floor. However, the discrepancy between substrate lability and DOC production, in combination with a rapid microbial processing of DOC released from labile C pools, illustrated the complicated nature of microbial production and consumption of DOC in the forest floor. [Copyright &y& Elsevier]

Introduction: Even though gait symptoms are prominent in patients diagnosed with multiple system atrophy with predominant parkinsonism (MSA-P) compared with Parkinson's disease (PD), the gait patterns of MSA-P were not clearly elucidated. We investigated postural instability and gait disturbances in MSA-P compared with PD.Methods: We enrolled 34 drug-naïve patients with PD and 26 with MSA-P, and 18 normal controls in this study. Parkinsonism was evaluated by the Unified Parkinson's disease rating scale (UPDRS) part 3 and cognition was assessed with mini-mental status exam (MMSE). All the enrolled subjects underwent Pedoscan and GAITRite to objectively measure postural stability and gait. We compared the results of posturography and gait analysis among 3 groups, and performed correlation analysis of gait parameters with MMSE, UPDRS part 3 and posturography results.Results: No difference was detected in demographic and clinical variables, except tremor sub-score of UPDRS part 3, urinary symptoms and orthostatic hypotension. MSA-P patients showed larger total anterior-posterior and lateral movement of centre of pressure (COP), and widened base of support than PD patients. In correlation analysis, MMSE score, axial sub-score of UPDRS part 3 and lateral movement of COP were correlated with gait parameters in PD patients, while only axial sub-score was associated in MSA-P patients after controlling for age, sex, height, body weight, education year, and disease duration.Conclusion: Even at an early stage, MSA-P patients demonstrated more postural instability and gait disturbance compared with PD patients, and the related factors with gait disturbance in PD and MSA-P might be different. [ABSTRACT FROM AUTHOR]

Dams and wastewater may greatly perturb riverine fluxes of dissolved organic matter (DOM) and CO 2 , yet little is known about the relationships between altered DOM quality and CO 2 emission in eutrophic impounded river systems. A basin-wide field survey of surface water CO 2 and dissolved organic carbon (DOC) was combined with laboratory incubations to examine how dams and urban tributaries delivering treated wastewater influence longitudinal patterns in DOM properties and CO 2 along the impounded Han River traversing Seoul metropolitan area. Fluorescent DOM indices including parallel factor analysis (PARAFAC) components were used to characterize DOM in relation to biodegradable DOC (BDOC). Compared with distinct downstream increases in DOC and CO 2 , BDOC concentration and its proportion in DOC (%BDOC) were highly variable along the mainstem and peaked at urban tributaries. Longitudinal increases in fluorescence index (FI), biological index (BIX), and two PARAFAC components (C2 and C3) contrasted with general decreases in humification index (HIX) and C1, reflecting increasing downstream inputs of anthropogenic DOM. During a 5-day incubation employing continuous CO 2 measurements, the cumulative production of CO 2 in the mainstem water mixed with urban tributary water was significantly higher than the level expected for conservative mixing of the two samples, indicating a synergistic enhancement of DOM biodegradation. Molecular formulas identified by Fourier transform-ion cyclotron resonance-mass spectrometry (FT-ICR-MS) revealed more consumed molecules in the mainstem water and more newly produced molecules in the tributary water over the 5-day incubation, implying abundant labile components in the mainstem water discharged from the upstream dam and highly processed tributary DOM limited in immediately biodegradable organic materials. Downstream increases in CO 2 and DOC along the Han River, combined with the synergistic effect observed in the mixed water, suggest that mixing wastewater-derived DOM with labile autochthonous DOM can enhance CO 2 production in the river system perturbed by impoundment and wastewater. Unlabelled Image • Field survey was combined with lab incubations to study human impact on river carbon. • Dissolved organic matter and CO 2 vary along impounded river with wastewater influence. • Urban tributary mixing enhances organic matter degradation and CO 2 in impounded river. • FT-ICR-MS detects organic matter degradation in impounded river and urban tributary. [ABSTRACT FROM AUTHOR]

Fallout radionuclides have been used successfully worldwide as tracers for soil erosion, but relatively few studies exploit the full potential of plutonium (Pu) isotopes. Hence, this study aims to explore the suitability of the plutonium isotopes 239 Pu and 240 Pu as a method to assess soil erosion magnitude by comparison to more established fallout radionuclides such as 137 Cs and 210 Pb ex . As test area an erosion affected headwater catchment of the Lake Soyang (South Korea) was selected. All three fallout radionuclides confirmed high erosion rates for agricultural sites (> 25 t ha − 1 yr − 1 ). Pu isotopes further allowed determining the origin of the fallout. Both 240 Pu/ 239 Pu atomic ratios and 239 + 240 Pu/ 137 Cs activity ratios were close to the global fallout ratio. However, the depth profile of the 239 + 240 Pu/ 137 Cs activity ratios in undisturbed sites showed lower ratios in the top soil increments, which might be due to higher migration rates of 239 + 240 Pu. The activity ratios further indicated preferential transport of 137 Cs from eroded sites (higher ratio compared to the global fallout) to the depositional sites (smaller ratio). As such the 239 + 240 Pu/ 137 Cs activity ratio offered a new approach to parameterize a particle size correction factor that can be applied when both 137 Cs and 239 + 240 Pu have the same fallout source. Implementing this particle size correction factor in the conversion of 137 Cs inventories resulted in comparable estimates of soil loss for 137 Cs and 239 + 240 Pu. The comparison among the different fallout radionuclides highlights the suitability of 239 + 240 Pu through less preferential transport compared to 137 Cs and the possibility to gain information regarding the origin of the fallout. In conclusion, 239 + 240 Pu is a promising soil erosion tracer, however, since the behaviour i.e. vertical migration in the soil and lateral transport during water erosion was shown to differ from that of 137 Cs, there is a clear need for a wider agro-environmental testing. [ABSTRACT FROM AUTHOR]

Abstract: The effects of treatment processes on estrogenicity were evaluated by examining estradiol equivalent (EEQ) concentrations in influents and effluents of sewage treatment plants (STPs) located along Yeongsan and Seomjin rivers in Korea. The occurrence and distribution of estrogenic chemicals were also estimated for surface water in Korea and compared with seven other Asian countries including Laos, Cambodia, Vietnam, China, Indonesia, Thailand and Malaysia. Target compounds were nonylphenol (NP), octylphenol (OP), bisphenol A (BPA), estrone (E1), 17β-estradiol (E2), 17α-ethynylestradiol (EE2) and genistein (Gen). Water samples were pretreated and analyzed by liquid–liquid extraction (LLE) and gas chromatography/mass spectrometry (GC/MS). The results showed that the treatment processes of Korean STPs were sufficient to reduce the estrogenic activity of municipal wastewater. The concentrations of phenolic xenoestrogens (i.e., NP, OP and BPA) in samples of Yeongsan and Seomjin rivers were smaller than those reported by previous studies in Korea. In most samples taken from the seven Asian countries, the presence of E2 and EE2 was a major contributor toward estrogenic activity. The EEQ concentrations in surface water samples of the seven Asian countries were at a higher level in comparison to that reported in European countries, America and Japan. However, further studies with more sampling frequencies and sampling areas should be carried out for better evaluation of the occurrence and distribution of estrogenic compounds in these Asian countries. [Copyright &y& Elsevier]

• A 25-year time series shows recent increases in N/P driven by decreasing P levels. • Harmful algal blooms concur with short-term changes in P, N/P, and temperature. • Cyanobacterial dominance lowers phytoplankton P use efficiency at low N/P. • CO 2 relationship with N/P or Chl a indicates phytoplankton biomass as a CO 2 source. Long-term trends in riverine nutrient availability have rarely been linked to both phytoplankton composition and functioning. To explore how the changing availability of N and P affects not only phytoplankton abundance and composition but also the resource use efficiency of N, P, and CO 2 , a 25-year time series of water quality in the lower Han River, Korea, was combined with additional measurements of riverine dissolved organic carbon (DOC) and CO 2. Despite persistent eutrophication, recent decreases in P relative to N have been steep in the lowest reach, increasing the annual mean mass ratio of N to P (N/P) from 24 (1994–2015) to 65 (2016–2018). While Chl a and cyanobacterial abundance exhibited overall positive and inverse relationships with P concentrations and N/P, respectively, severe harmful algal blooms (HABs) concurred with short-term increases in P and temperature. Microcystis often dominated HABs at low N/P that usually favors N-fixing cyanobacteria such as Anabaena. In the middle and lower reaches, phytoplanktonic P use efficiency was typically lower at low N/P. V-shaped relationships between N/P and CO 2 concentrations, together with longitudinal upward shifts in the inverse relationship between Chl a and CO 2 , implied that eutrophication-enhanced phytoplankton biomass could turn into a significant source of CO 2. after passing a threshold. The combined results suggest that cyanobacterial dominance co-limited by P availability and temperature can lower planktonic P use efficiency, while enhancing riverine CO 2 emissions at low N/P ratios. [Display omitted] [ABSTRACT FROM AUTHOR]

• N 2 O concentrations and isotopes reveal winter surges in wastewater and affected river • Low temperature lowers performance of wastewater N removal producing more N 2 O • Low temperature enhances N 2 O production via denitrification in hypoxic sediment Although eutrophic urban rivers receiving loads of wastewater represent an important anthropogenic source of N 2 O, little is known as to how temperature and other environmental factors affect temporal variations in N 2 O emissions from wastewater treatment plants (WWTPs) and downstream rivers. Two-year monitoring at a WWTP and five river sites was complemented with available water quality data, laboratory incubations, and stable isotopes in N 2 O and NO 3 − to explore how wastewater effluents interact with seasonal changes in environmental conditions to affect downstream metabolic processes and N 2 O emissions from the lower Han River traversing the megacity Seoul. Water quality data from four WWTPs revealed significant inverse relationships between water temperature and the concentrations or fluxes of total N (TN) in effluents. Increased TN fluxes at low temperatures concurred with N 2 O surges in WWTP effluents and downstream rivers, counteracting the long-term decline in TN fluxes resulting from enhanced wastewater treatments. Incubation experiments with river water and sediment, in isolation or combined, implied the hypoxic winter sediment as a large source of N 2 O, whereas the anoxic summer sediment produced a smaller amount of N 2 O only when it was added with oxic water. For both WWTP effluents and downstream rivers, bulk isotope ratios and intramolecular distribution of 15N in N 2 O distinctly differed between summer and winter, indicating incomplete denitrification in the hypoxic sediment at low temperatures as a primary downstream source adding to WWTP-derived N 2 O. Winter surges in wastewater TN and sediment N 2 O release highlight temperature variability as an underappreciated control over anthropogenic N 2 O emissions from increasingly urbanized river systems worldwide. Image, graphical abstract [ABSTRACT FROM AUTHOR]