Search Results (4)

Persistent organic pollutants (POPs) are well-known contaminants that raise serious concerns, even more than 20 years after they were banned. Their worldwide distribution and persistence necessitate continuous monitoring in all components of the environment. The most challenging issues of POP regulation are associated with international water resources because their solutions require international cooperation in environment protection. This review provides data on various POPs (DDT, HCH, endrin, dieldrin, and PCBs) and their concentrations in aquatic organisms inhabiting the Amur River basin, one of the most poorly explored regions of Northeast Asia. Most studies have been conducted in the Songhua River (China), a tributary of the Amur River, which indicates that large inland bodies of water, especially those of international importance, require more extensive research. Full article

The Heilong-Amur river basin (HARB) is the largest transboundary river in Asia and is primarily located in its cold region. With global warming and geopolitical cooperation strengthening between Russia and China, the hydrology change and water security risks are receiving increasing attention. This study utilized the linear regression, Mann–Kendall, and cumulative anomaly methods to analyze changes observed in the upper HARB’s streamflow and water levels over 30 years. The collation of outcomes derived from the methods mentioned above, the indicators of the hydrological alterations process, and the range of variability approach method (IHA–RVA), coupled with results gleaned from the double cumulative curve method, facilitate a thorough evaluation of the perturbations in hydrologic indicators, as well as the impacts of anthropogenic activities. The results showed that the overall hydrological regimes of both streamflow and water levels at the Luoguhe (LGH), the Shangmachang (SMC), and the Kalunshan (KLS) displayed a mild decrease from 1988 to 2017. The streamflow decreased by 58%, 42%, and 38%, and water levels decreased by 48%, 53%, and 59%, respectively, at each station after the mutations. LGH station recorded the highest decrease rate in streamflow at 8.28 × 10⁸ m³/a, whereas the steepest rate of decline in water levels was observed at KLS station at 0.05 m/a. Despite the decreasing trend in the high pulse count of streamflow across the three stations, a slight increase in the high pulse duration of streamflow was noted at SMC and KLS. Precipitation changes were the primary driving force behind runoff alterations, contributing 62%, 84%, and 90% at LGH, SMC, and KLS, respectively, significantly higher than the contribution from anthropogenic activities (38%, 16%, and 10%, respectively). These findings also underscore the suitability of the methodologies employed in this study for application in cold regions. Full article

Open biomass burning (OBB) is one of the major factors that influences the regional climate environment and surface vegetation landscape, and it significantly affects the regional carbon cycle process and atmospheric environment. The Amur-Heilong River Basin (ARB) is a fire-prone region in high-latitude boreal forests. In this study, we used fire radiative power (FRP) obtained from a Moderate-resolution Imaging Spectroradiometer (MODIS) to estimate OBB emissions from the ARB and established a long-term series (2003–2020) with a high spatiotemporal resolution and a daily 1 km emissions inventory. The results show that the annual average emissions of CO₂, CO, CH₄, NMHCs, NOx, NH₃, SO₂, BC, OC, PM_2.5, and PM₁₀ were estimated to be 153.57, 6.16, 0.21, 0.78, 0.28, 0.08, 0.06, 0.04, 0.39, 0.66, and 0.85 Tg/a, respectively. Taking CO₂ as an example, grassland fire in the dry season (mainly in April and October) was the largest contributor (87.18 Tg/a), accounting for 56.77% of the total CO₂ emissions from the ARB, followed by forest fire prone to occur in April–May (56.53 Tg/a, 36.81%) and crop fire during harvest season (9.86 Tg/a, 6.42%). Among the three countries in the ARB, Russia released the most total CO₂ emissions (2227.04 Tg), much higher than those of China (338.41 Tg) and Mongolia (198.83 Tg). The major fire types were crop fires (40.73%) on the Chinese side and grass fires on the Russian (56.67%) and Mongolian (97.56%) sides. Over the past decade, OBB CO₂ emissions have trended downward (−0.79 Tg/a) but crop burning has increased significantly (+0.81 Tg/a). Up to 83.7% of crop fires occurred in China (2010–2020), with a concentrated and southward trend. Comparisons with the Global Fire Emission Dataset (GFED4.1s), the Fire INventory from NCAR (FINNv2.2), and the Global Fire Assimilation System (GFASv1.2) showed that our newly established emission inventory was in good agreement with these three datasets in the ARB. However, this multi-year, daily 1 km high-resolution emission inventory has the advantages of detecting more small fire emissions that were overlooked by coarse-grid datasets. The methods described here can be used as an effective means of estimating greenhouse gas and aerosol emissions from biomass combustion. Full article

Megalobrama terminalis, which inhabits the Sino-Russian Heilong-Amur River Basin, has decreased critically since the 1960s. It has been listed in the Red Book of Endangered Fish Species by the Russian Federation in 2004. To guide the utilization and conservation programs of M. terminalis in the Heilong River (MTH), 3.1 kb of mitochondrial DNA (mtDNA) concatenated sequences and sequence-related amplified polymorphism (SRAP) markers (15 primer combinations) were applied to explore the genetic divergence and population differentiation of MTH within the genus Megalobrama. Clear genetic divergence between MTH and six other populations of the genus Megalobrama was found by haplotype network (mtDNA) and principal component (SRAP) analyses. Moreover, the STRUCTURE analysis based on SRAP data showed that MTH could be assigned to a particular cluster, whereas conspecific M. terminalis in the Qiantang River and Jinsha River Reservoir belonged to the same cluster. Analysis of molecular variance (AMOVA) and Fst statistics for the mtDNA and SRAP data revealed significant genetic variance and differentiation among all detected populations. Taken together, the results suggest that MTH has a strong genetic differentiation from other populations within the genus Megalobrama, which contributes to effective utilization in artificial cultivation and breeding of MTH. Furthermore, these results also provide a scientific basis for the management of MTH as a separate conservation unit. Full article