This study examined two underground coal mines in the Sydney basin and investigated the water chemistry impact from their wastewater discharges to surface receiving waters. One mine closed 17 years prior to the study, and the other was still active. The geology of both mine locations shared many similarities and some important differences that influenced their wastewater chemistry and its subsequent impact on receiving waterways. Water quality of wastewater discharges from the two mines and their receiving waterways was investigated over a 6-month period. Both mine discharges caused comprehensive modification to receiving water chemistry. The closed mine increased electrical conductivity (EC) 3.3 times from upstream (33 μS/cm) compared to downstream (108 μS/cm). In comparison, the active mine increased EC by 9.4 times (173 μS/cm) upstream to 1628 μS/cm downstream. Both coal mine wastes increased the concentration of different contaminants to levels that are potentially hazardous for receiving water ecosystems. The active mine increased bicarbonate concentration in the receiving water by more than 60 times to 743 mg/L. The closed mine increased zinc and nickel concentrations in its receiving stream by 70 and 20 times to 318 and 360 μg/L. The active coal mine discharge was dominated by sodium and bicarbonate ions compared to magnesium and sulphate ions in the closed mine drainage. Although both receiving waters were sodium and chloride dominated upstream of the mine waste, their ionic composition was strongly modified due to the inflow of coal mine wastes. Results from this study are a reminder that water pollution from coal mines is important for both active mines and for closed mines decades after mining activity ceases.

Research was carried out on the granulometric, mineral composition and fractional distribution of some elements in surface sediments of the Zeya River basin (Far East, Russia). The order of sediments’ pollution by heavy metals due to man-caused impact on the Zeya River’s ecosystem was determined. The compound forms of heavy metals in sediments were studied. It presented the most of the Fe, Ni, Cr, Mn, Co, Cu and Zn accumulated in bottom fraction; Pb and Cd—also in Fe and Mn hydroxides and bottom fractions. On average, 56% Pb, 83% Cd, 27–37% Cu, Co and Zn (of total amount) are held in geochemical moving forms.

This study focused on the treatment of effluent contaminated with chromium, being driven by the application of magnetic field studies in living cells and organisms. The objective was to quantify the removal of chromium(VI), total chromium, and total organic carbon (TOC) by applying a magnetic field generated by permanent magnets of neodymium in mixed culture. The resistance of microorganisms was evaluated for 4 h and 17 min against the application of a magnetic field at frequencies of 3, 5, and 10 Hz, which correspond to flow rates of 3.93, 7.07, and 14.92 cm³ s⁻¹ in the system loop, respectively. The initial concentration of Cr(VI) was 100 mg L⁻¹. The magnetic field frequency of 5 Hz showed a higher removal of Cr(VI) (100 %), total chromium (82 %), and TOC (34 %) compared with frequencies of 3 and 10 Hz and the absence of magnetic field exposure.

This is a green method for determination of mercury ion (Hg²⁺) in environmental samples. The method of exchangeable water based on liquid-liquid microextraction (EW-LLME) was first time introduced as a green analytical separation technique. Exchangeable water was made by the reaction of carbon dioxide with diethylenetriamine. The exchanging phenomena from low polarity to high polarity were confirmed by Fourier transforms infrared spectrometry. The complex formation between Hg²⁺ and 1, 5-diphenylcarbazone was achieved under the optimized experimental conditions. The enrichment factor and limits of detection of the present method were obtained to be 45.2 and 0.5 ng L⁻¹, respectively. The accuracy of the present method was confirmed with certified reference materials. The EW-LLME was successfully applied for determination of Hg²⁺ in solid matrices of block-III and V of Thar coalfield.

Industrial synthesis processes produce high concentration of hazardous organic pollutants into water body, which must be removed before being discharged. Advanced oxidation processes (AOPs) using heterogeneous catalysts has been widely utilized for wastewater treatment. Here, RuO₂-based catalyst was synthesized by a general impregnation method and used to oxidize phenol by peroxymonosulfate (PMS) as an oxidant in aqueous solution. The properties of this supported catalyst were characterized by SEM (scanning electron microscopy), XRD (powder X-ray diffraction), and nitrogen adsorption-desorption. The mesoporous Al₂O₃ support had large surface area and high thermal stability. It is found that ruthenium oxide-based catalyst is highly effective to activate PMS to related sulfate radicals. The effects of catalyst loading, phenol concentration, PMS concentration, reaction temperature, and reusability of the as-prepared catalyst on phenol degradation have been investigated. Overall, our findings demonstrate that in RuO₂/Al₂O₃ mesoporous catalyst, Oxone (PMS) is effectively activated, and 100% phenol degradation occurs in 60 min. To regenerate the deactivated catalyst and improve its catalytic properties, three different methods involving annealing in air, washing with water, and applying ultrasonics were used. The catalyst was recovered thoroughly by heating treatment.

Since the industrial revolution, the impact of effluents produced by human activities on ecosystems has been a major international environmental concern. This study was aimed at observing the changes in water and sediment qualities at a watershed level of two different river systems facing the same land use practices, but impacted to different degrees. Samples were collected at strategically selected sites within the mainstream of both rivers, the major tributaries draining into them, as well as a major impoundment in each system. A distinct difference between the two different rivers was observed. It was established that certain variables, for example pH, contributed to the differential water and sediment quality signatures in the upper Olifants and Mokolo rivers, having important considerations for the future management of both river ecosystems. Other abiotic factors, such as alkalinity and sulphate levels, were also found to be important. The tributaries were found to play an important role in the purification and/or pollution of the mainstream rivers. On the other hand, the present impoundments in the Mokolo River were observed to affect the water and sediment qualities downstream. Overall, through the use of comparative models, it was observed that the upper Olifants River was in a different state than the Mokolo River and the information from this study may aid in the future management of the Mokolo River to prevent a shift to an undesirable state.

To provide growing population with sufficient food, greenhouse vegetable production has expanded rapidly in recent years in China and sustainability of its farming practices is a major concern. Therefore, this study assessed the sustainability of greenhouse vegetable farming practices from environmental, economic, and socio-institutional perspectives in China based on selected indicators. The empirical data were collected through a survey of 91 farm households from six typical greenhouse vegetable production bases and analysis of environmental material samples. The results showed that heavy fertilization in greenhouse vegetable bases of China resulted in an accumulation of N, P, Cd, Cu, Pb, and Zn in soil, nutrient eutrophication in irrigation water, and high Cd in some leaf vegetables cultivated in acidic soil. Economic factors including decreased crop yield in conventional farming bases, limited and site-dependent farmers’ income, and lack of complete implementation of subsidy policies contributed a lot to adoption of heavy fertilization by farmers. Also, socio-institutional factors such as lack of unified management of agricultural supplies in the bases operated in cooperative and small family business models and low agricultural extension service efficiency intensified the unreasonable fertilization. The selection of cultivated vegetables was mainly based on farmers’ own experience rather than site-dependent soil conditions. Thus, for sustainable development of greenhouse vegetable production systems in China, there are two key aspects. First, it is imperative to reduce environmental pollution and subsequent health risks through integrated nutrient management and the planting strategy of selected low metal accumulation vegetable species especially in acidic soil. Second, a conversion of cooperative and small family business models of greenhouse vegetable bases to enterprises should be extensively advocated in future for the unified agricultural supplies management and improved agricultural extension service efficiency, which in turn can stabilize vegetable yields and increase farmers’ benefits.

Dhaka and its neighboring areas suffer from severe air pollution, especially during dry season (November–April). We investigated temporal and directional variations in particulate matter (PM) concentrations in Dhaka, Gazipur, and Narayanganj from October 2012 to March 2015 to understand different aspects of PM concentrations and possible sources of high pollution in this region. Ninety-six-hour backward trajectories for the whole dry season were also computed to investigate incursion of long-range pollution into this area. We found yearly PM₁₀ concentrations in this area about three times and yearly PM₂.₅ concentrations about six times greater than the national standards of Bangladesh. Dhaka and its vicinity experienced several air pollution episodes in dry season when PM₂.₅ concentrations were 8–13 times greater than the World Health Organization (WHO) guideline value. Higher pollution and great contribution of PM₂.₅ most of the time were associated with the north-westerly wind. Winter (November to January) was found as the most polluted season in this area, when average PM₁₀ concentrations in Dhaka, Gazipur, and Narayanganj were 257.1, 240.3, and 327.4 μg m⁻³, respectively. Pollution levels during wet season (May–October) were, although found legitimate as per the national standards of Bangladesh, exceeded WHO guideline value in 50 % of the days of that season. Trans-boundary source identifications using concentration-weighted trajectory method revealed that the sources in the eastern Indian region bordering Bangladesh, in the north-eastern Indian region bordering Nepal and in Nepal and its neighboring areas had high probability of contributing to the PM pollutions at Gazipur station.

Acrylamide (ACR), an environmental toxin though being investigated for decades, remains an enigma with respect to its mechanism/site of actions. We aim to explicate the changes in cerebral ganglions and giant fibers along with the behavior of worms on ACR intoxication (3.5–17.5 mg/mL of medium/7 days). Neurotransmitter analysis revealed increased levels of excitatory glutamate and inhibitory gamma amino butyrate with reduced levels of dopamine, serotonin, melatonin, and epinephrine (p < 0.001). Scanning electron microscopy showed architectural changes in cerebral ganglions at 3.5 mg/mL/ACR. The learning behavior as evidenced by Pavlovian and maze tests was also altered well at 3.5 mg/mL of ACR. Electrophysiological assessment showed a reduction in conduction velocity of the medial and lateral giant nerve fibers. We speculate that the observed dose/time-dependent changes in neurotransmission, neurosecretion, and conduction velocity on ACR intoxication at 17.5 mg/ml, possibly, could be due to its effect on nerve fibers governing motor functions. The bioaccumulation factor in the range of 0.38–0.99 mg/g of ACR causes a detrimental impact on giant fibers affecting behavior of worm. The observations made using the simple invertebrate model implicate that the cerebral ganglionic variations in the worms may be useful to appreciate the pathology of the neurological diseases which involve motor neuron dysfunction, esp where the availability of brain samples from the victims are scarce.

Long-term monitoring of the content of perchloroethylene (PCE) in a river ecosystem affected by groundwater contamination was performed at a site in the Czech Republic. The quality of surface water was monitored quarterly between 1994 and 2013, and fish were collected from the affected ecosystem to analyse the content of PCE in their tissue in 1998, 2011 and 2012. Concentrations of PCE (9–140 μg/kg) in the tissue of fish collected from the contaminated part of the river were elevated compared to the part of the river unaffected by the contamination (ND to 5 μg/kg PCE). The quality of surface water has improved as a result of groundwater remediation during the evaluated period. Before the remedial action, PCE concentrations ranged from 30 to 95 μg/L (1994–1997). Following commencement of remedial activities in September 1997, a decrease in the content of PCE in the surface water to 7.3 μg/L (1998) and further to 1 μg/L (2011) and 1.1 μg/L (2012) led to a progressive decrease in the average concentration of PCE in the fish muscle tissue from 79 μg/kg (1998) to 24 (2011) and 30 μg/kg (2012), respectively. It was determined that the bioconcentration of PCE does not have a linear dependence because the decrease in contamination in the fish muscle tissue is not directly proportional to the decrease in contamination in the river water. The observed average bioconcentration factors were 24 and 28 for the lower concentrations of PCE and 11 for the higher concentrations of PCE in the river. In terms of age, length and weight of the collected fish, weight had the greatest significance for bioconcentration, followed by the length, with age being evaluated as a less significant factor.