Lakes nested in forested watersheds play an important role in mediating the concentrations and fluxes of dissolved organic matter. We compared long-term patterns of concentrations and fluxes of dissolved organic carbon (DOC) and dissolved organic (DON) and inorganic nitrogen (DIN) in aquatic ecosystems of the Arbutus Lake watershed to evaluate how a lake nested in a forested watershed affects the sources (e.g., production) and sinks (e.g., retention) of DOC and DON in the Adirondack Mountains of New York, USA. We observed no significant long-term changes of DOC and DON in the lake outlet since 1983 and 1994, respectively. However, the temporal patterns of DOC and DON concentrations in the lake inlet showed significant seasonality such as increases during the vegetation-growing season along with notable decreases in the dormant season. A comparison of mass balances between inlet and outlet for the period from 2000 to 2009 suggested that the lake was a sink of DOC (mean of influx minus outflux: +1140 mol C ha⁻¹ yr⁻¹). In contrast, the difference of discharge-weighted DON concentrations (mean of inlet minus outlet: −1.0 µmol N L⁻¹) between inlet and outlet was much smaller than the discharge-weighted DOC concentrations (average of inlet minus outlet: + 87 µmol C L⁻¹). DON fluxes showed considerable variation among years (mean of influx minus outflux: +8 mol N ha⁻¹ yr⁻¹; range of differences: −15 to 27 mol N ha⁻¹ yr⁻¹). DON exhibited low percent retention ((influx-outflux)/influx) (mean: 6.9 %, range: −34.8 to +31.2) compared to DOC (mean: 30.1 %, range: +9.2 to +44.1). The resultant increase of DON within the lake was closely linked with a net decrease of DIN through monthly Pearson correlation analysis, suggesting the importance of biotic factors in mediating lake DON dynamics. Our results show different relative retentions of DOC compared with DON, along with a larger retention of DIN than DON, suggesting that DOC and DON might display substantially different biogeochemical relationships in oligo-mesotrophic lakes nested forested watersheds and therefore different roles for a sink behavior for DOC compared to a producer of DON.

The textile industry in South Korea is characterized by excessive water consumption, high concentrations of wastewater, hazardous chemicals, and high energy consumption. This study aimed to analyze Best Available Techniques Reference Documents (BREFs) based on best available techniques (BATs) and BAT-associated emission levels (BAT-AELs) and identify potential solutions for tackling environmental pressure from the South Korean textile industry. Therefore, the existing practices of the textile dyeing and finishing industry in South Korea were compared with those from the BREFs of the European Union. Many existing BATs in South Korea are related to reducing water consumption. There is also a strong focus on BATs for reducing wastewater discharge and achieving energy-saving during treatment rather than after treatment, which differs from other industries. Moreover, BAT-AELs were derived for chemical oxygen demand, suspended solids, and total nitrogen for treating non-biodegradable, highly polluted wastewater. Furthermore, BREFs related to atmospheric pollution included dust generated from the heated fabrics in the finishing process that contained cadmium and phenolic hydrogen chloride from dyes and raw materials in the fabrics. Notably, the European Union has not specified BAT-AELs for the textile industry, whereas South Korea has tailored BAT-AELs for toxic and hazardous chemicals. Thus, numerous green techniques to reduce emissions and energy consumption are being implemented in South Korea.

Pretreatment methods for measuring stable sulphur (δ³⁴S) and oxygen (δ¹⁸O) isotope ratios of dissolved sulphate from watersheds have evolved throughout the last few decades. The current study evaluated if there are differences in the measured stable S and O isotope values of dissolved sulphate from forested watersheds when pretreated using three different methods: Method 1 (M1): adsorb sulphate on anion exchange resins and send directly to isotope facility; Method 2 (M2): adsorb sulphate on anion exchange resins, extract sulphate from anion exchange resins, and send the produced BaSO₄ to the isotope facility; and Method 3 (M3): directly precipitate BaSO₄ without anion exchange resins with the precipitates being sent to the isotope facility. We found an excellent agreement of the δ³⁴S_sulphate values among all the three methods. However, some differences were observed in the δ¹⁸O_sulphate values (M1 versus M2:−1.5 ‰; M1 versus M3:−1.2 ‰) associated with possible O contamination before isotope measurement. Several approaches are recommended to improve the pretreatment procedures for δ¹⁸O_sulphate analysis.