We worked out a method in Maple environment to help understand the difficult transport processes in horizontal subsurface flow constructed wetlands filled with coarse gravel (HSFCW-C). With this process, the measured tracer results of the inner points of a HSFCW-C can be fitted more accurately than with the conventionally used distribution functions (Gaussian, Lognormal, Fick (Inverse Gaussian) and Gamma). This research outcome only applies for planted HSFCW-Cs. The outcome of the analysis shows that conventional solutions completely stirred series tank reactor (CSTR) model and convection-dispersion transport (CDT) model do not describe the internal transport processes with sufficient accuracy. This study may help us develop better process descriptions of very complex transport processes in HSFCW-Cs. Our results also revealed that the tracer response curves of planted HSFCW-C conservative inner points can be fitted well with Frechet distribution only if the response curve has one peak.

Harmful cyanobacterial blooms (HCB) have severe impacts on marine and freshwater systems worldwide. They cause oxygen depletion and produce potent cyanotoxins that have detrimental effects on human and environmental health and deteriorate the water quality. Biological treatment of the water for control of cyanobacterial blooms and removal of cyanotoxins can be a more economical and environment-friendly way, as they do not result in production of undesirable by-products. Most biological treatments of cyanobacteria and cyanotoxins have concentrated largely on bacteria, with little attention paid to algicidal fungi. Therefore, this review aims to provide an overview of the current status and the main progresses achieved in fungal biodegradation of HCB and cyanotoxin research. The available data revealed that 15 fungal species had high lytic activity against cyanobacteria, and 6 species were capable of degrading microcystins (MCs). Some fungal species (e.g., Aurobasidium pullulans and Trichoderma citrinoviride) have been identified to selectively inhibit the growth of cyanobacteria rather than beneficial species of other algal groups. Interestingly, some fungal strains (Trichaptum abietinum, Trichoderma citrinoviride) exhibited di-functional trait, being efficient in lysing cyanobacteria and degrading MCs released from the cells after decay. Beyond a comprehensive review of algicidal and toxin-degrading activities of fungi, this paper also identifies and prioritizes research gaps in algicidal fungi. The review also gives insights to the potential applications of algicidal fungi for removal of cyanobacterial blooms and their cyanotoxins from the aquatic environment.

PAH contamination in water environment has become an important water quality problem in China. In this study, groundwater PAHs were monitored in September 2019 at 48 groundwater sites, and statistical analysis and positive matrix factorization (PMF) model were used to analyze the characteristic of PAHs in groundwater and to identify the pollution sources of PAHs in the Hutuo River Basin, Hebei Province, China. The results showed that the concentration of the PAHs in groundwater was low and the total PAHs (∑PAHs) ranged from below detection limit to 260.6 ng/L and with a mean value of 17.7 ng/L. The concentration of PAHs in groundwater was obviously affected by the land use. Based on molecular ratio method, the main source of PAHs in groundwater is the biomass combustion, while the results of PMF source analysis were more accurate and the results showed that the primary sources and contribution rate of PAHs in groundwater were wood, coal, and gasoline sources (41.4%), followed by oil and diesel sources (39.4%), and natural gas combustion (19.2%). There was obvious spatial variation in the contribution of pollution sources to PAHs at the sites of different land uses in this region. The highest contribution of nature gas combustion, oil and diesel sources, and wood, coal, and gasoline combustion to PAHs was found in the urban area (0.617 ng/L), industrial area (0.380 ng/L), and village area (0.379 ng/L), respectively. The results can provide scientific basis for the prevention and control of PAH contamination in groundwater in this area.

The widespread existence of antibiotics has caused inevitable influence on ecology and humans. In this study, we screened the most commonly used antibiotics, and 64 antibiotics were detected in Shanghai, an international metropolis. Most of the target substances were detected in all 46 water samples including main rivers and districts in Shanghai, with concentrations ranging from 0.02 to 502.43 ng L⁻¹. In particular, sulfadiazine (502.43 ng L⁻¹) had the highest maximum concentration. Besides, risk quotients based on fish suggested that sulfonamides had a medium risk (0.12) in Shanghai. Correlation studies had shown that most compounds with frequencies exceeding 60% were significantly positively correlated with the total concentration. Based on further analysis, sulfadiazine, sulfamerazine, and sulfapyridine were screened as indicators to reflect the pollution status of antibiotics in Shanghai for a long time. The screening conditions for these indicators include detection rate (> 60%), maximum concentration (> 100 ng L⁻¹), RQ (> 0.01), and correlation (> 0). In addition, population density may be the main factor for antibiotic pollution through regional comparison. In a word, this work can systematically reflect the overall situation of Shanghai antibiotics and provide support for global data comparison in the future. Meanwhile, we provided the potential indicators that can be applied in the long term and economical monitoring of antibiotics.

In this study, alterations in behavior, oxidative stress, and related gene expressions, as well as histopathological changes in the brain, of zebrafish were evaluated following exposure to cadmium chloride and mercury chloride alone and in combination for 21 days. In the light–dark preference test, the time spent in the dark side and numbers of entries in the light side by zebrafish of all toxicity groups compared to those of control were significantly higher and lower, respectively. In novel tank test, times spent in the lower zone by zebrafish of toxicity groups were at par but significantly higher compared to those of the control group, which indicate the development of anxiety-like behavior in all toxicity groups. Zebrafish exposed to Cd + Hg showed significant downregulation of Nrf2 mRNA expression (Nrf2— protein that is responsible for the expression of antioxidant proteins) in the brain compared to other toxicity groups. The downregulation of Nrf2 plays a crucial role in cellular oxidative damage in the brain of zebrafish. The glutathione level of the brain was significantly decreased in Cd and Cd + Hg-exposed fish. However, the malondialdehyde level of the brain was significantly higher in Hg and Cd + Hg groups. Significant microscopic pathological changes were noticed in the olfactory bulb, corpus cerebelli, and optic tectum of zebrafish of all toxicity groups. The Cd + Hg-exposed group showed severe changes in periventricular gray zone of optic tectum. Significant synergistic toxicity in the brain was not observed following simultaneous exposure of Cd and Hg in zebrafish.

This paper explores the relationship between renewable energy consumption, urbanization, human capital, trade, natural resources, and material footprint for BRICS countries from 1990 to 2016. We apply the cross-sectional dependency test to check the correlation among the cross-section. Then, we use the second-generation panel test like CADF and CIPS to check the stationary in the series. After that, we go for the panel cointegration test, i.e., Pedroni and Westerlund panel cointegration, to know the long-run relationship of the variables. The test results reject the null hypothesis of no cointegration among the variables and accept cointegration. The long-run results indicate that economic growth, natural resources, renewable energy, and urbanization have reduced the environmental quality for BRICS countries in case of material footprint employed to measure environmental degradation. However, foreign trade and human capital improve environmental quality. Based on the empirical results, the study recommended some important policy suggestions to achieve sustainable development in BRICS countries.

Lead (Pb) exposure has been reported to have nephrotoxicity. However, such an effect has not been well investigated in type 2 diabetes (T2D) patients, especially when taking into account the nutrition status of the patients. Therefore, we explore the association between blood lead levels (BLLs), dietary intake of nutrients, and impaired renal function among patients with T2D. We measured BLLs and biochemical parameters of renal injury in 780 patients. Dietary nutrients intake was assessed by a food frequency questionnaire in 420 of 780 participants. We found high BLLs were significantly associated with certain parameters of renal injury, and dietary intake of specific nutrients (mainly micronutrients) was associated with reduced BLLs at high percentile distribution of concentration. BLLs were also found to have moderation effects on the association between specific dietary nutrients and specific renal function parameters.

This review presents important information about general aspects of the mining process as a source of environmental pollution, economic and health impact, microorganisms involved in the microenvironments resulting from ore exploitation, and resistance mechanisms to As and Zn, as a global vision of topics of interest to researchers or students involved in this field. The exploitation of mineral resources generates ideal but extreme microenvironments, where the growth of microorganisms adapted to high concentration levels of heavy metals in comparison to common soil occurs; tailings, contaminated soils, and acid mine drains are sources of culturable heavy metal–resistant microorganisms that naturally grow under stressful conditions. The present review focuses on As and Zn as heavy metal pollutants, due to their presence in high concentrations in mining wastes, regardless of geographic location and mineral processes, in addition to their toxicity; the low profile of Zn as a pollutant even at the alarming levels can be found in mining wastes and consequently in the environment; the impact of ore processing is also included and provides an overview of some of the data on the relationships of mining microbiology highlighting the potential of microorganisms to eliminate these compounds discharged by any means into the environment. The relevance of this compendium is to highlight the interaction of native microorganisms present in mining wastes with high concentrations of heavy metals (As and Zn) as a biological treatment to remove such contaminants as an alternative to conventional technologies.

Permanently submerged sediment samples (SS) were collected in the center stream of eleven tributaries of Changjiang (Yangtze River) and at eight confluence zones in the Three Gorges Reservoir (TGR) in May and December of 2017. The work showed that aqua regia digestion is a simpler, more reliable and robust method compared to total digestion with hydrofluoric acid (HF) for the determination of trace metals (TMs) in sediment for risk assessment purpose. Our study revealed a remarkable accumulation of TMs at the confluence zones and a trend of their gradual increase toward this zone. The presence of iron and manganese (oxy)hydroxides combined with hydrodynamic conditions created by the Three Gorges Dam (TGD) and its operation are believed to play a crucial role. This work also found that concentrations of [Formula: see text] in May sediment were significantly higher than those in December, which could have been caused by both the cyclic hydrodynamic conditions and the warmer water. TOC and TP were both very low in the sediment. Although TN was 2 times higher than the Lowest Effect Level suggested by the Ontario Ministry of Environment, it is uncertain if it reflects a natural background level or due to anthropogenic activities. A critical discussion is made by comparing the conclusions obtained when using different TMs risk assessment models. Necessary precautions are highly recommended when performing this exercise. In this study, no significant risk from either TMs or nutrients was identified.

The aim of this study was to evaluate the effect of pulp and leaves of Glycyrrhiza glabra to reduce the ruminal biogas production in sheep. Five experimental diets of two levels of Glycyrrhiza glabra pulp (GGP) and Glycyrrhiza glabra leaves (GGL) at 150 and 300 g/kg dry matter (DM) were assessed for biogas production and fermentation parameters. Diets were control (diet without GGP or GGL), GGP15 (diet contains GGP at 150 g/kg DM), GGP30 (diet contains GGP at 300 g/kg DM), GGL15 (diet contains GGL at 150 g/kg DM), and GGL30 (diet contains GGL at 300 g/kg DM). Inclusion of 150 and 300 g/kg GGP and 300 g/kg GGL decreased (P < 0.0001) asymptotic biogas production (A), fermentation rate (μ), biogas production at 24 h of incubation (GP₂₄), apparent degraded substrate (ADS), in vitro organic matter disappearance (OMD), and metabolizable energy (ME). Microbial protein biomass (MP) was improved (P = 0.003) by GGP15, GGL15, and GGL30 versus control. Total VFAs (P = 0.003), acetate (P = 0.009), and butyrate (P = 0.002), CH₄ (mmol and mL/g OMD), CO₂ (mmol and mL/g OMD) (P = 0.0003 and P = 0.0002, respectively), were decreased in GGP15, GGP30, and GGL30 diets versus control. Acetate to propionate ratio (Ac/Pr) was decreased (P = 0.038) in GGL30 diet compared to other diets. Replacing GGP and GGL with alfalfa reduced NH₃-N concentration (P = 0.022), total protozoa (P < 0.0001), Isotricha spp. (P = 0.047), Dasytricha spp. (P = 0.067), subfamilies of Entodiniinae (P < 0.0001), and Diplodiniinae (P = 0.06). Results suggested that inclusion of dietary GGL at 150 g/kg dry matter positively modified some rumen parameters such as microbial protein production, protozoa population, and NH₃-N concentration, which may be useful economically in ruminant animals and decreasing of environmental pollution.