Water pollution is an urgent problem that needs to be controlled via green transformation and the development of the Yangtze River Economic Belt (YREB). Based on the water pollutant discharge and socio-economic database of prefecture-level cities in the YREB from 2011 to 2015, this study explores the spatiotemporal variations in water pollutant discharge in the YREB via two main indicators: chemical oxygen demand (COD) and ammonia nitrogen (NH₃–N). Further, the spatial effects and determinants of water pollutant discharge are quantitatively estimated. The results show that (1) the water pollutant discharge in the YREB has decreased significantly, with the COD and NH₃–N discharge reduced by 10.46% and 10.79%, respectively, and the discharge reduction in the lower reaches was the most prominent; (2) the spatial pattern of water pollutant discharge in the YREB was generally stable and partially improved, and cities with a high rate of water pollutant reduction in the YREB were distributed in the main stream region of the Yangtze River and the intersection of the main stream and tributaries; (3) spatial effects had a significant impact on water pollutant discharge in the YREB, with regional cooperation and economic radiation through environmental management and control initially showing a combined reduction trend in regional water pollutants; and (4) determinants of population size and agricultural economic share declined to varying degrees at the end of the study period, although the urbanization level continued to increase, indicating that urbanization in the YREB occurred too quickly and that water pollutant discharge reduction was limited. However, economic development leading to the deterioration of the water environment was alleviated. In addition, foreign direct investment (FDI) inflows and rapid industrialization processes must be monitored to increase the reduction in characteristic water pollutants.

Economic development, population growth, industrialization, and urbanization dramatically increase urban water quality deterioration, and thereby endanger human life and health. However, there are not many efficient methods and techniques to monitor urban black and odorous water (BOW) pollution. Our research aims at identifying primary indicators of urban BOW through their spectral characteristics and differentiation. This research combined ground in-situ water quality data with ground hyperspectral data collected from main urban BOWs in Guangzhou, China, and integrated factorial data mining and machine learning techniques to investigate how to monitor urban BOW. Eight key water quality parameters at 52 sample sites were used to retrieve three latent dimensions of urban BOW quality by factorial data mining. The synchronically measured hyperspectral bands along with the band combinations were examined by the machine learning technique, Lasso regression, to identify the most correlated bands and band combinations, over which three multiple regression models were fitted against three latent water quality indicators to determine which spectral bands were highly sensitive to three dimensions of urban BOW pollution. The findings revealed that the many sensitive bands were concentrated in higher hyperspectral band ranges, which supported the unique contribution of hyperspectral data for monitoring water quality. In addition, this integrated data mining and machine learning approach overcame the limitations of conventional band selection, which focus on a limited number of band ratios, band differences, and reflectance bands in the lower range of infrared region. The outcome also indicated that the integration of dimensionality reduction with feature selection shows good potential for monitoring urban BOW. This new analysis framework can be used in urban BOW monitoring and provides scientific data for policymakers to monitor it.

Microplastic pollution in the Yangtze River Basin has become a major concern; however, the variations in different environmental compartments are unknown. Here, we compiled published information including detection methods, occurrence, and characterization of microplastics from 624 sampling sites in river water, river sediment, lake and reservoir water, and lake and reservoir sediment in the Yangtze River Basin. The spatial distribution of sampling sites shows fractal pattern and was uniformly concentrated around the main stream of the Yangtze River and the lake geographical zone. Collection, pretreatment, identification, and quantification processes varied among different studies. Non-parametric tests were performed to compare the different microplastic indices. A Pearson correlation analysis was used to study the relationship between microplastic pollution and local socioeconomic conditions. We found that the microplastic size and abundance distribution in river water and lake and reservoir water showed different patterns for different sampling methods, indicating that different methods influenced the results. Population density and urbanization rate are suggested to be important factors influencing the spatial heterogeneity of microplastic abundances in water, rather than in sediment. The microplastic abundances in lake and reservoir water were higher than that in river water in bulk samples. However, microplastic abundances among different sediment environments shows no significant difference. For bulk water samples and sediment samples overall, the proportion of small microplastics (<1 mm, i.e. SMP), fibers, transparent debris, and polypropylene (PP) were 65.1%, 67.8%, 31.8%, and 29.7%, respectively. The microplastic characteristics of lake and reservoir water and sediment were similar, differing from those of river water and sediment. This study provides the first basin scale insight into microplastic occurrence and characteristics in different environments in the Yangtze River Basin.

This study reports seasonal variations of meteorological parameters, atmospheric dust and dust-borne heavy metals concentrations measured, over a period of two years, next to two major airports (Dubai International Airport and Abu Dhabi International Airport) in the Gulf Cooperation Council (GCC) region. On-line monitoring stations were installed at each location next to dust samplers used to frequently collect PM2.5 and PM10 on Teflon filters for metal analysis. Clear seasonal variation in meteorological parameters were identified. The particulate matter concentrations depicted from the two locations were continuously monitored. The PM2.5 concentration ranged from 50 to 100 μg/m³ on normal days but reached 350–400 μg/m³ per day during mild storms. The PM10 levels ranged between 100 and 250 μg/m³ during normal days and spiked to 750 μg/m³ during mild storms. Energy Dispersive X-Ray Analysis (EDS) revealed the presence of significant amounts of alkali and alkaline earth metals, which pose potential harm to aircraft engines. ICP analysis showed the presence of heavy and toxic metals in concentrations that may pose harm to human health. Bulk sand samples from Abu Dhabi sites showed chemical similarities to the atmospheric dust samples. The concentrations of heavy metals, PM2.5, and PM10 are at levels that require further monitoring due to their impact on human health. The two years meteorological monitoring, with the seasonal variations, provided additional regional data in the Arabian Gulf. Furthermore, the study concluded that Sand and Dust storms (SDS) occur more frequently at the northern Arabian Gulf compared to its southern region. The chemical correlation between atmospheric dust and regional desert sand suggests the localized origin of the smaller dust particles that may form by breaking apart of the ground sand grains. As a result of the ongoing urbanization in the region, it is essential to collect additional data from various locations for a longer period of time.

As an important form of urban water resource, urban artificial lakes are severely affected by rapid urbanization and interference from human activities. These small lakes are characterized by their unique irregular shape, fragile ecosystem, and relatively closed, stagnant waterbodies. However, few studies have focused on their hydrodynamics and water quality, in particular the restoration methods and mechanisms remaining unclear. The present study applied the MIKE 21 FM model to investigate the effects of water diversion on water quality in a typical urban artificial lake. By considering different flow arrangements, several model scenarios were set up to predict the impacts of water diversion on selected water quality parameter. The results showed that the effectiveness of water diversion was directly related to flow velocity, the relative position to the fresh water inlet, the amount and quality of fresh water and water remaining to be diluted, and the circulation direction of flow field. The inflow–outflow arrangement was the primary factor determining the flow field and NH₃–N variation trends across the lake, and an increased discharge exhibited unequal effects in individual zones. Wind was also important for the formation of flow circulation and pollutant variation. Methods were proposed for enhancing water quality in urban small-scale lakes, including changing the way diversion projects are managed, improving the quality of diverted flow, enhancing flow fluidity, or utilizing wind effects and local topography.

Bivalves are useful bioindicators of microplastic contamination in the marine environment for several reasons, such as extensive filter feeding activity, broad geographical distribution, and limited movement capability. This study conducted a nationwide monitoring of microplastic pollution along the Korean coasts using filter-feeding bivalves (including oyster, mussel, and Manila clam) as bioindicators to identify the national contamination level and characteristics of microplastics. Seawater sample was collected from the same sampling stations of oyster and mussel for comparison. Microplastics were widely distributed in both coastal bivalves and waters with mean concentrations of 0.33 ± 0.23 n/g (1.21 ± 0.68 n/individual) in oyster/mussel, 0.43 ± 0.32 n/g (2.19 ± 1.20 n/individual) in Manila clam, and 1400 ± 560 n/m³ in seawater. Despite the lack of significant relationship in the abundance of microplastics, their dominant features such as size, shape, color and polymer type were similar between bivalves and seawater. Fragments (69% for oyster/mussel, 72% for Manila clam, and 77% for seawater), particles smaller than 300 μm (96% for oyster/mussel, 83% for Manila clam, and 84% for seawater) and colorless (79% for oyster/mussel, 85% for Manila clam, 75% for seawater) were the dominant shape, size and color, respectively. The major polymer types were polypropylene, polyethylene, and polyester. The microplastic level in bivalves was relatively high in urbanized areas with a wide diversity of polymer types compared with those in non-urbanized areas, and the proportion of polystyrene in the Korean samples was abundant compared with other regions due to wide use of polystyrene products in Korea. Our result suggests that microplastic contamination is widespread in the Korean coastal environment, and bivalves can reflect the microplastic pollution characteristics of the surrounding waters where they live.

Since the urbanization and industrialization are wildly spread in recent decades, the concentration of Zn in soil has increased in various regions. Although the interactions between P and Zn has long been recognized, the effect of high level of Zn on P uptake, translocation and distribution in rice and its molecular mechanism are not fully understood. In this study, we conducted both hydroponic culture and field trial with different combined applications of P and Zn to analyze the rice growth and yield, the uptake, translocation and distribution of P and Zn, as well as the P- and Zn-related gene expression levels. Our results showed that high level of Zn decreased the rice biomass and yield production, and inhibited the root-to-shoot translocation and distribution of P into new leaves by down-regulating P transporter genes OsPT2 and OsPT8 in shoot, which was controlled by OsPHR2-OsmiR399-OsPHO2 module. High Zn supply triggered P starvation signal in root, thereafter increased the activities of both root-endogenous and -secreted acid phosphatase to release more Pi, and induced the expression OsPT2 and OsPT8 to uptake more P for plant growth. On the other hand, high level of P significantly decreased the Zn concentrations in both root and shoot, and the root uptake ability of Zn through altering the expression levels of OsZIPs, which were further confirmed by the P high-accumulated mutant osnla1-2 and OsPHR2-OE transgenic plant. Taken together, we revealed the physiological and molecular mechanisms of P–Zn interactions, and proposed a working model of the cross-talk between P and Zn in rice plants. Our results also indicated that appropriate application of P fertilizer is an effective strategy to reduce rice uptake of excessive Zn when grown in Zn-contaminated soil.

Polycyclic aromatic compounds (PACs) are ubiquitous across environmental media in Canada, including surface water, soil, sediment and snowpack. Information is presented according to pan-Canadian sources, and key geographical areas including the Great Lakes, the Alberta Oil Sands Region (AOSR) and the Canadian Arctic. Significant PAC releases result from exploitation of fossil fuels containing naturally-derived PACs, with anthropogenic sources related to production, upgrading and transport which also release alkylated PACs. Continued expansion of the oil and gas industry indicates contamination by PACs may increase. Monitoring networks should be expanded, and include petrogenic PACs in their analytical schema, particularly near fuel transportation routes. National-scale roll-ups of emission budgets may not expose important details for localized areas, and on local scales emissions can be substantial without significantly contributing to total Canadian emissions. Burning organic matter produces mainly parent or pyrogenic PACs, with forest fires and coal combustion to produce iron and steel being major sources of pyrogenic PACs in Canada. Another major source is the use of carbon electrodes at aluminum smelters in British Columbia and Quebec. Temporal trends in PAC levels across the Great Lakes basin have remained relatively consistent over the past four decades. Management actions to reduce PAC loadings have been countered by increased urbanization, vehicular emissions and areas of impervious surfaces. Major cities within the Great Lakes watershed act as diffuse sources of PACs, and result in coronas of contamination emanating from urban centres, highlighting the need for non-point source controls to reduce loadings.

Urban turfgrass ecosystems are expected to increase at unprecedented rates in upcoming decades, due to the increasing population density and urban sprawl worldwide. However, so far urban turfgrasses are among the least understood of all terrestrial ecosystems concerning their impact on biogeochemical N cycling and associated nitrous oxide (N₂O) and nitric oxide (NO) fluxes. In this study, we aimed to characterize and quantify annual N₂O and NO fluxes from urban turfgrasses dominated by either C4, warm-season species or C3, cool-season and shade-enduring species, based on year-round field measurements in Beijing, China. Our results showed that soil N₂O and NO fluxes varied substantially within the studied year, characterizing by higher emissions during the growing season and lower fluxes during the non-growing season. The regression model fitted by soil temperature and soil water content explained approximately 50%–70% and 31%–38% of the variance in N₂O and NO fluxes, respectively. Annual cumulative emissions for all urban turfgrasses ranged from 0.75 to 1.27 kg N ha⁻¹ yr⁻¹ for N₂O and from 0.30 to 0.46 kg N ha⁻¹ yr⁻¹ for NO, both are generally higher than those of Chinese natural grasslands. Non-growing season fluxes contributed 17%–37% and 23%–30% to the annual budgets of N₂O and NO, respectively. Our results also showed that compared to the cool-season turfgrass, annual N₂O and NO emissions were greatly reduced by the warm-season turfgrass, with the high root system limiting the availability of inorganic N substrates to soil microbial processes of nitrification and denitrification. This study indicates the importance of enhanced N retention of urban turfgrasses through the management of effective species for alleviating the potential environmental impacts of these rapidly expanding ecosystems.

In this study, water and sediment samples from the Jiaozhou Bay and surrounding rivers were collected to analyze the seasonal occurrence and allocation of 12 organophosphate esters (OPEs) and the associated ecological risk. The higher contamination of OPEs in the adjacent rivers indicated the impact of terrestrial input. Tris(1-chloropropan-2-yl) phosphate (TCIPP) was the predominant OPE in the four environmental sample groups investigated. The spatial distribution of OPEs in seawater varied greatly seasonally and was mainly affected by terrestrial input, with OPEs being redistributed under the influence of tidal currents. The partition coefficients (log Kₒc) of the OPEs were calculated, and their strong correlation with the log Kₒw (octanol-water) values suggested that the water-sediment allocation was significantly affected by hydrophobicity. The homologous relationships among the 7 OPEs with detection frequencies greater than 40% were identified by principal component analysis (PCA). The partial least squares regression (PLSR) model explicated that ∑OPEs cycling dynamics and principal controlling factors were dissimilar in the bay versus surrounding rivers. The risk quotient (RQ) faced by typical organisms in seawater and river water indicated that short-term OPEs exposure was safe for green algae, daphnia and fish. The organisms in rivers faced the higher ecological risk of OPEs in spring than in summer and winter. Therefore, the terrestrial transport of OPEs in spring should be controlled.