Diatoms have been proven to be good indicators of natural stream conditions, but little is known about the seasonal variability of diatom communities in megacity streams. We investigated the spatial and temporal variation of diatom communities along an urban-to-rural gradient in megacity streams, Beijing, China. We found that the composition and diversity of diatom community was significantly different along the urban-to-rural gradient in streams of Beijing city. The diatom community was subtle temporal variation in the reference stream and urban upstream, but the temporal variation of diatoms was relatively greater in the urban downstream. Overall, the composition of the diatom community was relatively stable in the streams among different seasons, and the dominant species did not change much over seasons. For example, during the sampling periods, the species Achnanthidium minutissimum in reference streams had the average relative abundance of 20.3 ± 3.5%; the species Pseudostaurosira brevistriata and Staurosira construens var. venter in urban upstream had average relative abundances of 17.0% ± 0.9% and 17.3% ± 1.2%, respectively; and the species Nitzschia palea in urban downstream had average relative abundances of 18.8 ± 4.7%. There were significant correlations between the relative abundances of the dominant species and environmental variables, suggesting that the environmental variables had significant effects on the diatom distribution. Our results demonstrate that the diatom communities are relatively stable among seasons in different sampling areas, suggesting that diatoms can be used as reliable indicators for the biological monitoring of water quality in megacity streams across seasons.

The aim of this study was to explore the enterprises in the mining area, in the face of environmental pollution, to use relationship embedding to acquire new key knowledge from the external network, and to improve environmental governance performance. In this paper, a model between relationship embedding and environmental governance performance was established, and five main hypotheses were proposed. Luliang Mountain Area is a typical mining area in China. And this study used 310 sample datum and regression analysis to empirically test the mechanism, taking Luliang Mountain Area as an example. First, SPSS statistical software was used for reliability and validity analysis of the questionnaire, and the results showed good. Then regression analysis was performed to test the hypothesis. The results showed that relationship embedding has a significant positive impact on environmental governance performance, and enterprises in the mining area use relationship embedding to obtain key knowledge, which can enhance environmental governance performance. Internal social capital has a positive adjustment effect on the relationship between relationship embedding and knowledge acquisition. In order to control environmental pollution in the mining area, enterprises should make full use of the relationship embedding, acquire new key knowledge, improve environmental governance capacity, and improve the environmental governance performance of enterprises.

The presence of plastic debris < 5 mm called microplastics (MPs) which results mainly from macroplastic’s fragmentation has been reported in aquatic ecosystems. Several studies have shown that MPs are persistent and their accumulation was observed in various aquatic species. However, the majority of studies focused on marine species, and much less on continental and estuarine biota. The goal of the present study was to investigate the effects of a mixture of two types of MPs (polyethylene and polypropylene), frequently found in natural environments, towards the ragworm Hediste diversicolor to determine their accumulation in organisms exposed through the water phase or sediment. Two concentrations of exposure were selected for medium and heavily contaminated areas reported for water phase (10 and 100 μg/L) and sediment (10 and 50 mg of MPs/kg). To study the potential toxic effect of MPs, immune parameters were selected since they are involved in many defense mechanisms against xenobiotics or infectious agents. An average number of MP items/worm ranging from 0 to 2.5 and from 1 to 36 were identified in animals exposed to the lowest and the highest concentration of MPs through water exposure. In worms exposed through sediment, less than 1 MP/worm was found and a greater number of particles were identified in depurated sediment. For immunotoxic impact, MP exposure induced a decrease in coelomocytes viability, but no alteration of phagocytosis activity, phenoloxydase, and acid phosphatase was measured. This study brings new results on the potential accumulation and immunotoxicity of MPs for the ragworm H. diversicolor who plays a key role in the structure and functioning of estuarine ecosystem.

The materials and byproducts of the processes used in the metal finishing industry are released as particle contaminants into the air in the workplace. The present study aimed to determine the concentrations and size distributions of these particles and of elements chromium, nickel, copper, manganese, cobalt, and lead (Cr, Ni, Cu, Mn, Co, and Pb, respectively) in a metal finishing industry and evaluate their potential health risks. Particles that are airborne from the dipping baths in the plant were sampled using a Sioutas cascade impactor at five different size fractions (PM>₂.₅, PM₁.₀–₂.₅, PM₀.₅–₁.₀, PM₀.₂₅–₀.₅, PM<₀.₂₅) and gravimetric analyses were conducted on the sampled filters. The GF-AAS 600 graphite atomic absorption spectrophotometer (PerkinElmer Corporation, Waltham, MA, USA) was used to analyze the elements and the method of USEPA was used to assess the health risk. The ratio of fine particles (PM₂.₅) to total suspended particles (TSPs) was 0.6. We observed that 50% of TSPs were composed of PM₁.₀ and that 68–88% of the metals were found in the fine particle fractions. Pb, Cr, and Mn were significantly positively correlated in the PM₁.₀ fraction, and the highest linear relationship was found between Pb and Cr (r = 0.85, p < 0.01). The total hazard quotient (HQ) for PM₂.₅ was 1.43, which is higher than the acceptable limit of 1.0. The excess lifetime cancer risk (ELCR) for hexavalent chromium (Cr[VI]) in PM₂.₅ was 6.09 × 10⁻⁵ for female workers and 6.54 × 10⁻⁵ for male workers, which are higher than the acceptable limit of 1.0 × 10⁻⁶, while total ELCRs for female and male workers were 6.21 × 10⁻⁵ and 6.21 × 10⁻⁵, respectively. The lifetime cancer risk associated with Cr(VI) in Cr electroplating plants should be taken into consideration as a significant health risk for the workers.

Until now, a number of epidemiological studies have focused on the association between ambient particulate matter pollution and chronic obstructive pulmonary disease (COPD), especially in developed countries. There are limited evidences on the association between short-term exposure to particulate matters (PM₂.₅, PMC, and PM₁₀) and overall hospital outpatient visits for COPD at the same time in China. Thus, a time-series analysis on the short-term association between three subtypes of PM (PM₂.₅, PMC, and PM₁₀) and daily hospital outpatients for COPD in Lanzhou, China was conducted, from 2014 to 2017.An over dispersed, generalized additive model was used to analyze the associations after controlling for time trend, weather conditions, day of the week, and holidays. Stratified analyses were also performed by age and gender. The results disclosed that a 10-μg/m³ increase in PM₂.₅ concentration at a lag of 0–7 days was associated with 1.190% (95% CI 0.176~2.215%). For PMc, therewere not statistically significant effects at any lag days, but we could find the greatest effect at lag07 that a 10-μg/m³ increase in concentration was associated with 0.014% (95% CI − 0.065~0.093%). PM₁₀ also exerted a high effect for COPD (0.185% increase; 95% CI − 0.046~0.417%) when 6 days of exposures (lag6), however, no significance relationship could be found. For COPD among males, positive results were observed for PM₂.₅ with lags of 0–7 days, a 10-μg/m³ increase was 1.184% (95% CI 0.095~2.284%). The effect of PM₂.₅ on females was also most significant at lag07, a 10-μg/m³ increase was 1.254% (95% CI 0.053~2.469%). For those aged < 65 years old, PM₂.₅ was not statistically significant at all lag days, but it reached the maximum at lag07, a 10-μg/m³ increase was 0.978% (95% CI − 0.139~2.108%). For those aged 65 ≥ years old and older, PM₂.₅ had a statistically significant lag effect at lag1, lag2, lag3, lag02, lag03, lag04, lag05, lag06, and lag07, and it was most significant at lag07; a 10-μg/m³ increase was 1.906% (95% CI 0.553~3.277%). Short-term exposure to PM₂.₅ was associated with increased risk of hospital visits for COPD. In particular, the elderly (aged ≥ 65 years old) and males were relatively more sensitive to PM₂.₅, and were affected right away after the PM₂.₅ concentration went up.

Water level (a vital indicator for flood warnings and water management in floodplains) has been changed notably due to climatic and anthropogenic forces; however, very little is known about the relative effects of these agents. In this study, we take the Taihu Plain as an example to investigate potential factors driving changes in water level components through quantiles from 1954 to 2014. To quantify the extent of water level component changes attributable to climate variability and human activity, several non-stationary models considering rainfall, tide, evaporation, and hydraulic regulation as covariates are established based on generalized additive models for location, scale, and shape. The results indicate that most water level components increased over time and changed abruptly around the mid-1980s. As for climatic factors, the variability of rainfall, tide and evaporation significantly affected water level variation based on most quantiles from 1954 to 2014. Among several kinds of human activities, hydraulic regulation was a key factor influencing water level based on a high correlation coefficient. Positive effects were identified from hydraulic regulation regarding the association between rainfall and water level components; these effects depend on water level quantiles and the amount of rainfall occurrence. Our study has broad implications, providing a better understanding of water level variation and regional flood management.

Water supplies in coastal aquifers throughout the world are often threatened by salinization due to seawater intrusion and anthropogenic activities. In the Kalpitiya Peninsula in Sri Lanka, agricultural and domestic water supplies entirely depend on groundwater resources extracted from unconfined Holocene sandy aquifers. To differentiate the effects of seawater intrusion and agriculture on the coastal aquifers of this 160 km² peninsula, 43 groundwater samples were collected. These samples were analyzed for major ions, trace elements, and stable isotopes of water (δ¹⁸O and δ²H). The solute compositions were dominated by Cl⁻, [Formula: see text], and [Formula: see text], which were mostly balanced by Ca²⁺, Na⁺, and Mg²⁺. Among the four main water types, Na⁺-Cl⁻ and Ca²⁺-[Formula: see text] classifications were predominant in the investigated aquifers. Modifications of the groundwater due to evaporation during irrigation activities, but also due to seawater intrusion seem most plausible as indicated by the correlation of δ¹⁸O with δ²H (δ²H = 5.51 * δ¹⁸O-3.08, r = 0.93) deviating from the local meteoric water line. Particularly in the southern part of the peninsula, Mg²⁺/Ca²⁺ ratios and stable isotopes of water attributed salinization of groundwater to agricultural activities. However, especially in the north, seawater intrusions were also evident. Established mass balance calculations revealed that local groundwater had seawater admixtures of up to 12%. Our results indicate that integrated water management is essential and water resources should critically monitor in the Kalpitiya Peninsula in order to avoid over-exploitation and further seawater inflows.

The formation of highly graphitic phenolic resin chars (GPFCs) during catalytic carbonization at relatively low reaction temperature (1200–1600 °C) using novel Ni-Zn-B alloy catalyst with small amount of addition (5–15%) was systematically studied. Only two kinds of graphites (turbostratic graphite and ordered graphite) can be found in GPFCs after catalytic carbonization with Ni-Zn-B and their proportions were changed with reaction conditions. When Ni-Zn-B was involved at 1200–1600 °C, the phenolic resin char was fully transformed to be graphite, and ordered graphite content increased to 28.42% at 1400 °C, which was also almost twice of ordered graphite content in the char catalyzed by pure Ni. But the order graphite content would decrease due to sintering at higher reaction temperature. The addition of Zn and B can promote nickel-based alloy catalytic action by reducing melt point and accelerating graphitization respectively. It was also found that ordered graphite content could be used as a key evaluation parameter to directly reflect the quality of GPFCs based on detailed characteristics analysis. The model between three reaction conditions (reaction temperature, retention time, catalyst content) and ordered graphite content was built with artificial neural network (ANN), and the prediction accuracy of ANN was high up to 91.48%.

In recent decades, many authors have investigated possibility of simultaneous reduction of income inequality and pollution related to climate change. However, none of the previous researches reviewed the empirical studies of relationship between inequality and CO₂ emissions. The authors of the selected papers, published from 2001 to 2019, found a diverse impact of income inequality on carbon dioxide (CO₂) emissions. It could depend on different trajectories of Kuznets curves. Furthermore, the majority of authors have provided theoretical analysis (even including human behaviour) of the influence of income inequality on CO₂ emissions, considering only territorial (or production-based) emissions. However, this paper recommends to distinguish between the production-based and consumption-based emissions and suggests the revised approaches to the impact of income inequality on CO₂ emissions with regard to the production-based and consumption-based emissions. Regarding the production-based emissions, the following approaches are proposed: (i) determination of environmental policies, which also could reveal and explain the leakage phenomenon, and the channels of EKC, i.e. (ii) scale, (iii) composition, (iv) technical and (v) globalization effects. The influence of income inequality on consumption-based emissions can be explained by applying two approaches, namely (i) inequality determined changes in working time (this approach is also related to “Veblen effect”) and (ii) individual economic behaviours of households. Therefore, the present study provides a new insight into the subject of the relationship between income inequality and pollution related to climate change.

Litter is a well-known problem for marine species; however, we still know little about the extent to which they're affected by microplastics. In this study, we analyse tl1e presence of this type of debris in Western Mecliterranean striped dolphins' intestinal contents over three decades. Results indicated that frequency was high, as 90.5% of dolphins contained microplastics. Of these microplastics, 73.6% were fibres, 23.87% were fragments and 2.53% were prirnary pellets. In spite of the high frequency of occurrence, microplastic amount per dolphin was rela­tively low and highly variable (mean ± SD = 14.9 ± 22.3; 95% CI: 9.58--23.4). Through FT-IR spectrometry, we found that polyacrylamide, typically found in synthetic clothes, was the most common plastic polymer. Here, we establish a starting point for further research on how microplastics affect this species' health and discuss the use of striped dolphins as indicators of microplastics at sea.