Surface water and groundwater are significant for population and other activities due to the decreasing surface water flow toward Iraq. Therefore, there is a need to analyze groundwater’s quality and classification and its applicability as an alternative in various human activities in the study area. This study utilized the groundwater quality index model for drinking uses (GW.Q.I.) and entered the resulting values in the GIS environment. This model was applied to 56 wells in Al-Hillah city by measuring twelve variables in each well. The measured variables were calcium (Ca), magnesium (Mg), sodium (Na), chloride (Cl), sulfate (SO4), bicarbonate (HCO₃), total hardness (TH), total dissolved solids (TDS), nitrate (NO₃), and electric conductivity (EC). The prediction map of GW.Q.I. was produced in the GIS. Then, the distributing map was divided into six categories based on the suitability of groundwater for drinking uses. The areas’ values of six categories with their ratings were about 5 km² (excellent), 122 km² (good), 610 km² (poor), 63 km² (very poor), 36 km² (contaminated), and 24 km² (very contaminated). For the entire study area, the average value of the GW.Q.I. was 177, classified as poor for drinking uses.

The production and use of titanium dioxide (TiO₂) nanoparticles are increasing worldwide. The release of this substance into the environment can induce toxic effects in aquatic invertebrates and vertebrates, although the exact nature of its impacts on Neotropical amphibians is still poorly understood. In this context, the present study evaluated the toxicity of TiO₂ nanoparticles and their counterpart—dissolved titanium dioxide (TiO₂)—in the tadpoles of Dendropsophus minutus. The biometric parameters, DNA damage, and behavioral changes were verified in tadpoles exposed to three different concentrations (0.1 mg·L⁻¹, 1.0 mg·L⁻¹, and 10 mg·L⁻¹) of TiO₂ nanoparticles and dissolved TiO₂ for 7 days. We verified significant DNA damage in the D. minutus tadpoles exposed to both forms of Ti, in comparison with the control group. We also identified a reduction in total size, body length, and width, and the height of the musculature of the tail of the tadpoles exposed to all concentrations of both substances in comparison with the control. In the behavioral test, the tadpoles exposed to nanoparticles and dissolved TiO₂ presented reduced mobility and a tendency to be less aggregated than normal. Here, the simultaneous use of multiple biomarkers was fundamental for the reliable assessment of the adverse effects of nanomaterials on anuran amphibians and the establishment of a systematic approach to the biomonitoring of aquatic ecosystems. The present study expands our understanding of the genotoxic, morphological, and behavioral effects of TiO₂ nanoparticles and dissolved TiO₂ on anuran amphibians, and contributes to the establishment of further research for the more systematic assessment of the environmental risk of nanomaterials.

The phenomenon of “equifinality for different parameters” limits the link between parameters and catchment characteristics; however, solving the equifinality problem is a major challenge in the development, generalization, and application of a model. This study focused on the Yanhe River Watershed to investigate the time-varying characteristics of sensitivity and identifiability of SWAT (Soil and Water Assessment Tool) runoff and sediment parameters based on the Sobol’ and generalized likelihood uncertainty estimation methods. The results indicate that (i) the nondominated sorting genetic algorithm-II has good adaptability and reliability in parameter calibration of the SWAT model in the Yanhe River Watershed. The evaluation indicators (Nash–Sutcliffe efficiency, R², and percent bias) of monthly runoff and sediment in the Ganguyi hydrological station were all satisfactory per the SWAT model during the calibration and validation periods. (ii) The interaction between runoff and sediment parameters is a crucial reason for parameter sensitivity, which has obvious time-varying characteristics and is largely dependent on precipitation in the Yanhe River Watershed. Temporal and spatial variability of precipitation should be considered in the detailed analysis of parameter identifiability, and watershed managers should not ignore changes in the runoff process when regulating sediment. (iii) Only a relatively small number of parameters can be identified in the runoff and sediment simulation process of the Yanhe River Watershed, such as CN2 (initial soil conservation service runoff curve number for moisture condition II), CH_K2 (effective hydraulic conductivity in main channel alluvium), ALPHA_BF (baseflow alpha factor), USLE_C (cover and management factor), USLE_P (support practice factor), and USLE_K (soil erodibility factor), due to high surface runoff, reduced lag time, reduced low flows, increased peak flows, and channel erosion, respectively. More importantly, there is a strong positive correlation between parameter identifiability and parameter sensitivity. Both are effective methods of parameter diagnosis, but the identifiability of parameters is not equivalent to its sensitivity. Our results strongly suggest that a detailed parameter sensitivity and identifiability analysis is a critical step in improving hydrological model performance to reduce the risk of “equifinality for different parameters” while articulating all relevant hydrological processes.

Durability performance of concrete is enhanced by adding supplementary cementitious materials such as fly ash. The concrete made with addition of fly ash with Portland cement is called fly ash cement concrete (FACC). Generally, modelling approach is applied to predict the service time of concrete in aggressive environment. Most degradation of concrete is found in marine environment, due to the exposure of concrete to chlorides. Service life modelling is performed using diffusion equation (Eq. 1) with diffusion coefficient (D) equation (Eq. 2), and to get the diffusion coefficient (D) over time, ageing factor is used for analysis. During modelling stage, as this phase of study is started well before construction, concrete for its durability performance is checked. As well, service life modelling is performed for the existing structures, so that the time to failure may be obtained. In recent times, failure of Miami Building, USA, June 2021, has raised the importance of service life modelling (SLM) of reinforced concrete structures (RCC) in chloride environment. So, in such environments, a more need of more reliable results is raised. Presence of a number of ageing factors in literature raises a question which ageing factor is more approximate. Dependency of performance of modelling approach is on the selection of more approximate values. So, in present study, performance of ageing factors for fly ash cement concrete (FACC) is checked. So, literature was surveyed and the long-term chloride diffusion coefficient (D) values were obtained for fly ash cement concrete (FACC). It was found that a significant difference is present in the predicted values with different available ageing factors. Since results obtained from modelling depend on the parameters, so it can be assumed that the variation of chloride diffusion coefficient (D) will vary the results. So, in present study, a new ageing factor was developed. Service life modelling for durability with fly ash cement concrete (FCC) may be relied on the newly developed ageing factors, as this will give better results, which will be more reliable.

The present study aims to examine the impact of climate change on wheat and rice yield in Punjab, India, during 1981–2017. The study employs fully modified ordinary least squares (FMOLS), dynamic ordinary least squares (DOLS), and pooled mean group (PMG) approaches. The Pedroni cointegration has established a long-run relationship of climate variables with rice and wheat crops. FMOLS and DOLS models show that minimum temperature has a positive effect on both wheat and rice. In contrast, the maximum temperature is found to be negatively contributing to both crops. Rainfall has a significant adverse impact on the production of wheat. In the study period, seasonal rainfall has been found detrimental for the production of wheat and rice crops, indicating that excess rainfall proved counterproductive. Moreover, the Dumitrescu-Hurlin causality test has revealed a unidirectional causality running from minimum temperature, rainfall, and maximum temperature for rice and wheat production. The findings of the study suggest that the government should invest in developing stress-tolerant varieties of wheat and rice, managing crop residuals to curb other environmental effects, and sustaining natural resources for ensuring food security.

Microbial sulfate reduction, a vital mechanism for microorganisms living in anaerobic, sulfate-rich environments, is an essential aspect of the sulfur biogeochemical cycle. However, there has been no detailed investigation of the diversity and biogenesis contribution of sulfate-reducing bacteria in arsenic-contaminated soils from realgar deposits. To elucidate this issue, soil samples from representative abandoned realgar deposits were collected. Microcosm assays illustrated that all three samples (2–1, 2–2, and 2–3) displayed efficient sulfate and As(V)-respiring activities. Furthermore, a total of 28 novel sequence variants of dissimilatory sulfite reductase genes and 2 new families of dsrAB genes were successfully identified. A novel dissimilatory sulfate-reducing bacterium, Desulfotomaculum sp. JL1, was also isolated from soils, and can efficiently respiratory reduce As(V) and sulfate in 4 and 5 days, respectively. JL1 can promote the generation of yellow precipitates in the presence of multiple electron acceptors (both contain sulfate and As(V) in the cultures), which indicated the biogenesis contribution of sulfate-reducing bacteria to the realgar mine. Moreover, this area had unique microbial communities; the most abundant populations belonged to the phyla Proteobacteria, Chloroflexi, and Acidobacteriota, which were attributed to the unique geochemistry characteristics, such as total organic carbon, total As, NO₃⁻, and SO₄²⁻. The results of this study provide new insight into the diversity and biogenesis contributions of sulfate-reducing bacteria in arsenic-contaminated soils from realgar deposits.

Field-scale combined ecological treatment systems (FCETS) are designed to remove nutrients from aquaculture wastewater in ponds according to the characteristics of the nutrients present. We designed and established a numerical model based on the system dynamic (SD) method, to optimize the parameters of FCETS. Results showed that the mean removal rates of TSS, TN, NO₃⁻-N, NH₄⁺-N, TP, DP, and CODMₙ ranged from 83.3 to 125.8%, 41.1 to 49.1%, 44.8 to 56.2%, 49.3 to 55.6%, 80.0 to 88.2%, 52.6 to 65.0%, and 52.0 to 61.5%, respectively. The SD model provided satisfactory estimates of water quality at the outlet throughout both the validation and calibration periods. In addition, we conducted a sensitivity analysis to determine the key parameters of the SD model. This also involved optimization of the N and P removal capacity of FCETS, and their corresponding discharge (Q), and concentration (C) at the inlet. This made it possible to use R and MATLAB to simulate seasonal differences in the removal of N and P. Our results indicate that a FCETS can be used to efficiently remove nutrients from rural wastewater in ponds. In addition, we demonstrated that the SD-based numerical model is a useful management support tool to ensure that decisions are made which result in the stable operation of a FCETS. This illustrates that contamination-free aquaculture from rural inland ponds is a feasible goal.

Energy plays a vital role in promoting sustainable economic development in complex societies. This study has analyzed the impact of electricity consumption on three European Union member countries’ economic growth, i.e., Portugal, France, and Finland, caring structural breaks in cointegration analyses. The empirical results indicate a positive impact of electric power consumption on economic growth in the long and short run in Finland and Portugal and in the long run in France. The findings also highlight the positive and significant role of the labor force in boosting economic growth in the long and short run in France and Finland. However, it shrinks economic growth in the long run in Portugal. The study discloses the positive role of capital in the long run in the case of Portugal. Similar results are found in all three countries in the short run. Moreover, the study diagnoses a bidirectional causal relationship between economic growth and electric power consumption in Finland in the long and short run and in France in the long run. A growth-promoting or electricity-led growth hypothesis is found in Portugal. By simulating the mean values of electric power consumption, economic growth follows an increasing trend in all the countries. Hence, electric power consumption has appeared an essential factor in elevating economic growth in all three selected countries. Based on these results, this study suggests that the provision of electricity supply ventures may be expanded in the selected EU member countries in order to enhance economic growth. The study also suggests that emphasis should be shifted from non-renewable energy sources to renewable energy sources to ensure the provision of clean energy to all the public under the umbrella of sustainable development goals of 2030. Hence, the present study contributes to achieving sustainable economic growth in the selected EU member countries.

This study examines how economic complexity, along with human capital, total factor productivity, foreign direct investment, and trade openness, leads to per capita CO₂ emissions (PCO₂Es) convergence at club level in the case of 42 countries for the period of 1998–2019. To do so, first, this study implements the Phillips and Sul novel club convergence approach, and results show the existence of three clubs implying the distinct transition paths. Secondly, to examine how the economic complexity affects the PCO₂Es in each club, this study applies a panel data model. This study finds the divergence in PCCO₂Es when all 42 countries are considered together. However, there is existence of three clubs that are converging to their steady states due to economic complexity along with control variables. Further, the impact of economic complexity on PCO₂Es is found to be different for the three clubs. For instance, a positive and significant relationship has been noted for clubs 1 and 2 (high and moderate PCO₂Es). This implies that economic shifts in these countries degrade the environment. While in the case of club 3, we find a negative and significant relationship suggesting an improvement in the environmental quality. From the policy point of view, it can be suggested that environmental policies should be designed at the club level by targeting economic complexity. Further, club 1 and club 2 may improve the environmental quality by adopting some of the successful environmental policies from club 3 countries.

Polyhalogenated carbazoles (PHCZs) are a kind of emerging contaminants with doxin-like toxicity, potential bioaccumulation capability, and persistence. Data about the risks of PHCZs on soil ecosystem are scarce to date, although PHCZs have been detected with high concentrations in the soil. The present study performed a preliminary investigation of 3,6-dibromocarbazole (36-DBCZ, a PHCZ with a high detection rate, and concentration in the environment) at concentrations of 0.1, 1.0, 10, and 100 mg/kg on the soil health, based on soil enzyme test and Biolog-ECO assay. Results showed that 36-DBCZ could inhibit the activity and diversity of soil microbes, even at the environment-relevant concentration (0.1 mg/kg). But, the inhibition lasted only about 10 days. As time passed, slight increases in microbe activity and diversity were found in 36-DBCZ-treated groups. We hypothesized that the degradation products of 36-DBCZ provided extra nutrients to the soil microbes, which required further verification. Activities of urease, β-glucosidase, and acid phosphatase were increasingly increased, in contrast to the microbial activity. The present study provides valuable data on the effects of PHCZs on the soil ecosystem, and we suggest that the degradation of PHCZs, as well as their influences on the structure and functions of the soil microbial community, should be investigated in future studies.