Groundwater sources are drastically changing in their quantity and quality depending on local and regional level natural and anthropogenic factors, influencing their suitability for drinking and irrigation purposes. The objective of this study is to characterize the hydrochemistry and assess the groundwater quality in the fluvial deltaic plains of Cauvery river basin, Tamil Nadu, India. A total of 50 georeferenced groundwater samples were collected across Needamangalam block of Thiruvarur district and analyzed for major ions and hydrochemical processes. The results showed an ionic sequence of Cl⁻ > Na⁺ > HCO₃⁻ > Mg²⁺ > Ca²⁺ > CO₃²⁻ > SO₄²⁻ > K⁺ based on their relative proportions. The scatter diagram indicated that groundwater chemistry was mostly influenced by weathering dominance followed by evaporation and silicate weathering. The dominant hydro-chemical facies were Na⁺-Cl⁻-HCO₃⁻ type, Na⁺-Mg²⁺-Cl⁻-HCO₃⁻ type, Na⁺-Cl⁻-HCO₃⁻-CO₃²⁻ type and Na⁺-Mg²⁺-Cl⁻-HCO₃⁻-CO₃²⁻ type influenced by the ion-exchange reaction. Most of the groundwater samples are suitable for drinking and irrigation except few with higher Na⁺ and Cl⁻ content caused by the mixing of salt from fluvio-marine sources or agriculture return flow. The high sodium content in irrigation water may affect the soil hydraulic and nutrient properties in the long run.

Vertical eddy diffusivity (VED) is used to quantify the vertical mixing of water column, which has a profound influence on the evolution of aquatic ecosystems. Based on half-hourly water temperature measured at −20 cm and −150 cm depths from 2015 to 2017 at stations of Pingtaishan (PTS), Dapukou (DPK), Bifenggang (BFG), and Xiaoleishan (XLS) in Taihu Lake, the daily average VED is calculated according to the phase lag of water temperature series at two depths. The temporal and spatial features and possible evolution characters of vertical turbulences are then deliberated. The results show that the VED in Taihu Lake varies by several orders of magnitude. The weak VED exhibits stronger spatial heterogeneity and high frequency characteristics and vice versa for the strong VED. The VED in the center region of the lake is stronger, in comparison to bay areas. On seasonality, the VED is the strongest in winter, moderate in spring and autumn, and the weakest in summer. Analyses show that solar radiation and wind forcing are the key meteorological factors regulating VED changes, with the solar effect somewhat stronger than wind. It is also discussed potential roles of vertical mixing in cyanobacteria becoming dominant population in Taihu Lake.

In this work, the effect of polyethylene microplastics (MPs) on the adsorption of decabromodiphenyl ether (BDE-209) in a sandy loamy soil and aqueous solution was investigated by performing batch tests. Results show that the overall adsorption capacity of soil/MPs mixture decreased slightly after MPs spiking because of the dilution effect, namely MPs were weaker receptor for BDE-209 than the soil particles. The adsorption capacity increased with reducing the MPs size. The equilibrium adsorption amount of aged MPs (4.15 mg/kg) declined apparently compared with that of the original MPs (7.63 mg/kg). According to the fitting parameters of kinetic and isothermal adsorption study, the adsorption of BDE-209 by MPs was a heterogeneous and multi-layer uneven adsorption process. The existence of Cu²⁺ ions or humic acid exerted a negative impact on the adsorption of BDE-209. In summary, the findings of this work underline the potential significance of MPs as contaminant carriers in co-contaminated soils.

The present study was designed to evaluate the health effects of dietary nanozinc prepared by two methods: conventional chemical method and green method. The parameters evaluated were the extent of bioaccumulation, antioxidant status, histological, immunological changes and DNA damage in Nile tilapia fed nanozinc feed. Zinc oxide nanoparticles were first prepared by green and chemical methods. Before feed preparation, the in vitro antioxidant activity and antibacterial activity of both types of nanoparticle solutions were tested and the results revealed enhanced activities in green synthesized ZnO NP solution. After the acclimatization period, 420 Nile tilapias were distributed randomly into 21 glass tanks with 20 fish per tank in triplicates. Fish were fed control diet without any ZnO NP and (i) GT1—green synthesized ZnO NP diet at 100 mg/kg, (ii) CT1—chemically synthesized ZnO NP diet at 100 mg/kg, (iii) GT2—green synthesized ZnO NP diet at 200 mg/kg, (iv) CT2—chemically synthesized ZnO NP diet at 200 mg/kg, (v) GT3—green synthesized ZnO NP diet at 400 mg/kg and (vi) CT3—chemically synthesized ZnO NP diet at 400 mg/kg for 60 days. After 60 days, gill and liver samples were collected for analysing oxidative stress, histopathological alterations and bioaccumulation of zinc, whereas serum samples were collected for evaluating immune response. The results revealed that the GT3 diet significantly (P < 0.05) enhanced the level of antioxidant enzymes (CAT, SOD, GPx, GR and GSH) than dietary nanozinc prepared by the chemical method. Similarly, the innate immunological parameters were significantly (P < 0.05) augmented in fish fed GT3 diet. Comparative histological study of liver and gill tissues revealed normal architecture in the tissues of fish fed green synthesized NP–enriched feed, whereas the tissues of fish fed chemically synthesized NP feed exhibited histological alterations. Bioaccumulation of zinc was more in the liver followed by the muscle and least in the gills and DNA damage was more evident in fish fed chemically synthesized ZnO NP–enriched feed. In conclusion, the results suggest that the inclusion of 400 mg/kg GT3 diet in fish diet enhanced the level of antioxidant enzymes, boosted immune response and did not cause histological damage to organs, and therefore, GT3 nanofeed can be recommended for fish health improvement.

S-doped NiFe-based particles were prepared by a solvothermal method and used to degrade methylene blue (MB) aqueous solutions with visible light in a heterogeneous Fenton reaction. The obtained solid samples were characterized by XRD, SEM, TEM, and XPS. It was found that 0.2 g L⁻¹ NiFe₂S₄ can degrade 99.8% MB solution within 6 min in the presence of 5 mM H₂O₂ and natural pH. The recycle experiments results indicate that the NiFe₂S₄ catalyst possessed better stability than NiFe₂O₄. Furthermore, NiFe₂S₄ particles can be easily separated from contaminant solution by using a magnet due to their excellent ferromagnetism. COD analysis experiments indicated that the COD removal rate of NiFe₂S₄ is 73.1% in 30 min. A possible mechanism was proposed, and the degradation products were measured by LC-MS.

The growing adverse impact of IT products in developing countries like Pakistan is increasing, seeking academicians’ and practitioners’ attention to adopt green IT products in Pakistan. In this regard, several researchers provided different independent theoretical models for adopting green IT, but which model fits best in the scenario is still vague. Therefore, this study used three well-developed competing models: the technology acceptance model, the unified theory of acceptance and use of technology, and the decomposed theory of planned behavior to investigate green IT adoption in Pakistan. For this purpose, data were collected through a survey method using a purposive sampling technique, and partial least squares structural equation modeling (PLS-SEM) was used to analyze three competing models. Using the PLS model selection criteria along with standard model selection criteria, the results suggested that the decomposed theory of planned behavior (DTPB) is the most parsimonious and has the best explanatory and predictive power than other available alternative theoretical models. Moreover, the study identified different significant factors affecting consumers’ intention to adopt green IT products in Pakistan. The theoretical and practical implication of this study is discussed. In the final section, limitations and future directions are elaborated.

There are increased concerns about the thyroidal effects of many anthropogenic substances in the environment. These substances include agricultural pesticides and industrial and pharmaceutical chemicals among others. Their potential thyroidal effects are of serious health and ecological concerns, as thyroid hormones mediate numerous physiological processes, including growth regulation, general metabolism and metamorphosis in metamorphic animals. This study assessed thyroidal activities of Arsenal formulation (Imazapyr) at environmentally relevant concentrations of 0.5, 2.0 and 3.5 mg/L following a Xenopus metamorphosis assay (XEMA). The result shows that the Arsenal formulation significantly delayed the tadpole development, reduced the hind-limb length (HLL) and increased the whole-body mass (WBM) at a concentration of 3.5 mg/L relative to the control exposure. In histopathology, the formulation increased the epithelium height, at all exposure concentrations, but reduced the colloidal area at 0.5 and 2 mg/L, respectively, and the gland area at 2 mg/L relative to the control. Consequently, the Arsenal formulation is thyroid-active at environmentally relevant concentrations and poses a threat to both human and wildlife, especially metamorphic organisms. With this exposure impact, more studies are imperative to further characterise other endocrine-disrupting potential of this formulation, while future applications should be reduced or restricted to less risk environment, if it cannot be stopped from sensitive aquatic systems

Coal fly ash (CFA) and coal-based incense sticks ash (ISA) have several similarities and differences due to the presence of coal as a common component in both of them. CFA are produced from the combustion of pulverized coal during electricity production in the thermal power plants while ISA are produced from the burning of incense sticks at religious places and at houses. A typical black colored Indian, incense sticks are mainly are comprised of coal powder or potassium nitrate, wood chip, fragrance, binder or binding agent, and bamboo sticks. The black colored incense sticks have coal powder or charcoal as a facilitator for smoother burning of incense sticks. The detailed investigation of CFA and ISA by X-ray fluorescence spectroscopy (XRF), electron diffraction spectroscopy (EDS), inductively coupled plasma-atomic emission spectroscopy (ICP-AES), Fourier transform-infrared (FTIR), X-ray diffraction (XRD), particle size analyzer (PSA), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) revealed the morphological, chemical, and elemental properties. Both the coal based ashes comprises minerals like calcites, silicates, ferrous, alumina, and traces of Mg, Na, K, P, Ti, and numerous toxic heavy metals as confirmed by the XRF, ICP-AES, and EDS. While, microscopy revealed the presence of well-organized spherical shaped particles, namely cenospheres, plerospheres, and ferrospheres of size varying from 0.02 μm to 7 microns in CFA. Whereas, ISA particles are irregular, aggregated, calcium to carbon rich whose size varies from 60 nm to 9 microns and absence of well-organized spherical structures. The well developed and crystalline structure in CFA is due to the controlled combustion parameter in thermal power plants during the burning of coal while incense sticks (IS) burning is under uncontrolled manner. So, FTIR and XRD confirmed that the major portion of fly ash constitutes crystalline minerals whereas ISA have mainly amorphous phase minerals. CFA have ferrospheres of both rough and smooth surfaced, which was absent from the ISA and hence ferrous particles of CFA are of high magnetic strength. The detailed investigation of ashes will lead to the applications of ashes in new fields, which will minimize the solid waste pollution in the environment.

Ineffective environmental regulation of effluent discharged from an underground coal mine operation has enabled water pollution within two highly valued Australian rivers. This study investigated the impacts on water chemistry of the Bargo and Nepean rivers as a result of the continuous disposal of mine effluent from Tahmoor Colliery over a 14-month period. Coal mine effluent was saline (2180 μS/cm) and alkaline (8.7 pH), and strongly modified the ionic composition within both rivers. Ecologically hazardous concentrations of several metals were found in mine effluent, including aluminium (858 μg/L), arsenic (59.7 μg/L), nickel (60.7 μg/L), and zinc (49.4 μg/L). The effluent also contained elevated total nitrogen (2.89 mg/L) and the waste discharge contributed 67% of the median flow volume in the Bargo River below the discharge point. The plume of saline- and metal-enriched contamination extended at least 9 km downstream past the discharge point, impairing water quality in both the Bargo and Nepean rivers. This study reveals more than a decade of ineffective regulatory and governance systems that enable Tahmoor Colliery to continually release inadequately treated mine effluent.

Aluminum, mercury, and iron have been found in high concentrations in various freshwater bodies around the world and have been shown to be very harmful contaminants to hydrobionts, causing metabolic dysfunction and damage at various levels. However, studies on mixtures of these pollutants are scarce, particularly in younger or developing organisms, which are more sensitive to damage. Therefore, the objective of this work was to evaluate the toxicity of Al, Fe, and Hg, in isolation and in mixture, on common carp embryos exposed to the maximum permissible limits described in the Mexican regulations for the protection of aquatic life, correlating the biomarkers of oxidative stress with the effects on embryonic development. For this purpose, the Cyprinus carpio embryos were exposed to iron (0.1 mg L⁻¹), mercury (0.00001 mg L⁻¹), aluminum (0.05 mg L⁻¹), and their mixture, throughout their development and until hatching. The activity of the antioxidant enzymes (SOD, CAT, and GPx), the degree of lipoperoxidation, and the content of hydroperoxides and total proteins, as well as the morphological development of the embryos were evaluated at 12 h, 24 h, 48 h, 72 h, and 96 h of exposure. The results showed that the metals under study are toxic to C. carpio embryos and that their interaction modifies the toxic response. Thus, iron generates alterations in the activity of antioxidant enzymes and modification in embryonic development to a lesser extent than aluminum and the mixture of metals, while mercury exerts its toxicity on embryos by mechanisms other than oxidative stress, but the modification to the activity of antioxidant enzymes may contribute to the changes observed in embryonic development. The changes in the response of biomarkers of embryotoxicity and oxidative stress suggest that the combination of metals produces an antagonism-type interaction, so this study provides a precedent for future research to determine the type of interaction that a mixture of contaminants generates in developing aquatic organisms.