The purpose of this study is to investigate the relationship between official development assistance (ODA) on CO₂ emissions based on both direct and indirect frameworks, using the annual panel data of 30 recipient countries of Korea from 1993 to 2017. It employs a modified impact, population, affluence, and technology (IPAT) model and a simultaneous equation framework for the direct model and indirect model, respectively. The empirical results suggest that ODA has both a direct and an indirect mitigation impact in the recipient countries. Compared to the direct impact, a small indirect mitigation impact of ODA on CO₂ emissions is derived. However, the estimation results of the environmental Kuznets curve (EKC) equation imply that economic growth has the potential of mitigating the environmental degradation when the economic development in recipient countries of Korea reaches a certain level. Therefore, the bilateral cooperation, through ODA and the supportive policy, should make an effort to promote economic development and mitigation of environmental degradation in developing countries.

Heavy metals (Sc, Cr, Co, Ni, Cu, Ga, Ge, Nb, Mo, Cd, In, Hf, Ta, W, Tl, Pb, Bi, Th, and U) in the surface sediments of the Ganges-Brahmaputra-Meghna (GBM) river system of the Bengal Basin (BB) were measured to evaluate the heavy metal contamination and anthropogenic influence. The average concentration levels of most of the heavy metals (except Mo and Tl) were above the average crustal and shale values. Contamination indices, including the contamination factor, pollution load index, enrichment factor, and geo-accumulation index, and multivariate statistical analyses indicated that the GBM is slightly polluted by heavy metals with some considerable pollution from Bi, Th, Ta, Cd, Nb, Pb, In, and U. Among the four individual rivers, the Brahmaputra River and Ganges-Brahmaputra (GB) confluence river sediments contain higher heavy metal concentrations than do the Ganges and Meghna Rivers, which may be caused by the effects of local municipal discharge, industrial or urban wastes, and ferry crossing activities.

Uses of iron oxide nanoparticles have increased in the last decade. The increased application marked a concern regarding their fate and behavior in the environment. Especially towards the aquatic ecosystems, as the ultimate descend of these iron oxide nanoparticles are aquatic bodies. The greater surface area per mass compared with larger-sized materials of the same chemistry renders these nanoparticles biologically more active. Therefore, it is imperative to assess their eco-toxicogical impact on aquatic eco-systems. In the present study, comparative assessment of iron oxide nanoparticles and their bulk counterpart have been monitored using Coelastrella terrestris up to 40 days. Interestingly, study reveals the potential of Coelastrella terrestris as tool for the bioremediation of iron nanoparticles to combat nano-pollution. Adsorption/absorption kinetics measured after 25 days of treatments with iron oxide nanoparticle and its bulk counterpart revealed higher absorption levels in comparison to the adsorption with maximum accumulation factor (AF) of 2.984 at 50 mg L⁻¹ in nano-form. Iron oxide absorption was found linearly related with concentration in both cases (y = 11.313x-12.165, R² = 0.8691 in nano; y = 6.35x-5.74, R² = 0.8128 in bulk). However, 50-mg L⁻¹ nanoparticle concentration was perceived sub-lethal for the algae with 33.33% algal growth reduction under nano and 27.77% under bulk counterpart. Other biochemical parameters, i.e., SOD, CAT, MDA, and lipid quantification, were also quantified to correlate the state of metabolism of treated algal cells in comparison to the control and these exhibited reduction in algal growth due to oxidative stress. Morphological changes were monitored through SEM and TEM.

This study aims to synthesize a dust suppressant for controlling coal dust pollution in open yards using natural polymers. Guided by graft copolymerization theory, potassium persulfate acts as an initiator to excite the free radicals of collagen and sodium alginate, allowing them to combine with acrylic acid and acrylamide to form a new polymer. The TG curve indicates that the thermal stability of the polymer is superior to that of the raw material. Scanning electron microscope (SEM) images show that the product can reduce the generation of dust by bonding the pulverized coal. With CCD method, when the monomer concentration increases in a certain range, the cohesive ability of the product to coal increases first and then decreases. Initiators and crosslinkers showed the same pattern. A series of performance experiments show that the product has a dust suppression rate of 98.7% at a wind speed of 14 m/s, and maintain one of 94.5% at a wind speed of 8 m/s after a rainstorm. In addition, there was no significant loss in dust suppression performance and compressive strength of the solidified layer after wind and rain. Sunlight, low temperature, and high temperature have little influence on the dust suppression effect of the product, which indicates that the product has better weather resistance and helps to suppress dust for a longer time in open air conditions.

The present work designs a low-cost biological treatment strategy consisting of constructed wetlands (CWs) followed by entrapped algae (EA) for removing nutrients (PO₄³⁻, NO₃⁻, and NH₄⁺) and organic matters from high-strength wastewater. The CWs are efficient means for organic pollutant removal but face challenges in nutrient removal. Algae have a high growth rate and nutrient uptake capabilities from wastewater. The severe challenge that limits the use of algae for nutrient removal from wastewater is its post-treatment separation from wastewater. This work presents a strategy to address the described problems of CWs and algae-based system. It also assesses the performance of the system using synthetic wastewater. A combined system of CW followed by EA (CW-EA) was able to treat 86.0% of phosphate, 95.0% of nitrate, 74.0% of ammonium, and 87.0% of chemical oxygen demand (COD) from high-strength wastewater.

Dredging and disposal of sediments onto land sites is a common practice in urban and industrial areas that can present environmental and health risks when the sediments contain metallic elements. The aim of this study was to characterise and study the environmental and toxicological availability of Cd and Pb in anthroposols from dredged river sediments. To do this, 67 surface samples spread over 12 sediment disposal sites in northern France were studied. The results showed substantial heterogeneity for this matrix in terms of physicochemical parameters and contamination degree; however, ascending hierarchical clustering made it possible to classify the samples into eight groups. For each group, the mobile fraction of Cd and Pb was studied using single EDTA extraction, solid-phase distribution was analysed with sequential extractions and toxicological availability was assessed with the oral bioaccessibility test. The results showed that (i) Cd had a higher environmental and toxicological availability than Pb; (ii) this availability depends on the physicochemical characteristics of the matrix; and (iii) it is necessary to take into account the environmental and toxicological availability of contaminants when requalifying these sites in order to propose appropriate management measures. In the first years after sediment disposal, it would appear that the environmental and toxicological availability of Cd and Pb increased (from 52.5 to 71.8% and from 28.9 to 48.9%, respectively, by using EDTA and from 50.2 to 68.5% for Cd with the bioaccessibility test). Further studies would therefore be required to confirm this trend and understand the mechanisms involved.

Explore whether waterpipe dependence in young Lebanese adults would have any effect on modifying the association between risk conception, attitude, and other risky behaviors. A cross-sectional study was carried out using a proportionate cluster sample of Lebanese university students (3384 students). Waterpipe dependence was associated with higher association of alcohol dependence and cigarette dependence by 76.7% and higher excitement for dangerous behaviors by 7.1%. It was significantly associated with increased association of cigarette dependence and alcohol dependence by 66.8%, with the thinking of a behavior of being not dangerous by 239%, with having motives for risky behaviors by 74.1%, with ever having unsafe sex by 111.74%, and between having motives for risky behaviors and ever having unsafe sex by 61.95%. Waterpipe dependence was associated with higher motives, excitement, and perception of risk and risky behaviors, namely cigarette dependence, alcohol dependence, and unsafe sex. Moreover, it was associated with higher risky behavior interdependence.

In order to learn about the status of heavy metals and ecological risks in the water of thirteen China’s costal shellfish culture areas, principal component analysis was applied to analyze the distributions of five kinds of heavy metal, while the safety threshold method was employed to evaluate the ecological risks. The results showed that among the 13 shellfish culture areas, the average metal concentrations were in the order of Zn > Cu > Pb > Hg > Cd, and all heavy metals were below the second standards for sea water quality of China. The distribution of heavy metals in 13 shellfish culture areas was reflected by two principal components with the contribution rates of F1(Cu) and F2(Zn, Pb) were 36.14% and 23.40%,respectively,which was less affected by economic and geographical differences. The ecological risks assessment of five kinds of heavy metals showed that MOS10 was more than one; the probabilities of five heavy metals affecting more than 10% of aquatic organisms were 49.52%, 24.11%, 17.49%, 22.05%, and 5.66%, respectively, the ecological risk of five main heavy metals was in order Cu > Zn > Cd > Pb > Hg. In the selected thirteen shellfish culture areas, the value of msPAF of seven culture areas was higher than 20%, indicating these areas are highly ecologically contaminated by heavy metals, and the other four shellfish culture areas with value of 0, indicating that these areas have no ecological risk of heavy metals pollution.

The continuous decline in the resource and environment-carrying capacity of cultivated land resources has seriously threatened the sustainable supply of cultivated land resources in China. Using the Hicks-Moorsteen total factor productivity index method, we examine the total factor productivity of cultivated land use (CL-TFP) in China from 2003 to 2017 under environmental constraints. We further use a panel Tobit model to estimate the effect of its influencing factors. The results show that the CL-TFP presents a fluctuating upward trend and reaches data envelopment analysis (DEA) efficiency during the sample period. The regional results reveal a significant spatial difference, especially in the mid-west region, which fails to reach DEA efficiency. China’s main cultivated land did not realize economies of scale. The phenomenon of spatial polarization in what we refer to as very low-value areas and very high-value areas is clear, and the changes are gradual. Regarding the determinative influencing factors, results from the panel Tobit model show that cultivated land usage tax and environmental pollution control investment have no significant effect on CL-TFP, while income level and agricultural intermediate consumption do have a positive effect on CL-TFP. The empirical evidence can help policymakers craft and frame effective policies that improve the utilization efficiency of China’s cultivated land resources.

Planktonic ciliate composition and distribution together with physicochemical variables were investigated in a shallow hypersaline lagoon, Pulicat, India, during three seasons, i.e., pre-monsoon (PRM), monsoon (MON), and post-monsoon (POM). The low freshwater inflow, evaporation, and closure of the lake mouth were the main factors for the hypersaline conditions in Pulicat Lake. The average depth and salinity were 1.8 ± 0.12 m (0.8 to 2.8 m) and 35.3 ± 1.68 (12.5 to 61), respectively. A total of 29 ciliate taxa belonging to 18 genera and five classes were identified. Strombidium conicum (24%) was the dominant species followed by Euplotes sp. (10.7%) and Stenosomella sp. (7.02%). Spirotrichea (84%) was the dominant class followed by Oligohymenophorea (9.6%) and Heterotrichea (5.8%). Fabrea salina, a typical species in hypersaline systems, was abundant at locations where the salinity was more than 35. Multivariate analysis using the Bray–Curtis similarity, followed by SIMPROF (Similarity Percentage Analysis), on ciliate abundance data revealed three ciliate assemblages characterizing south, central, and north of the lake at 40% similarity (SIMPROF, cophenetic correlation = 0.622, P = 5%). Both ciliate abundance and chlorophyll-a were positively correlated with salinity. Species richness and evenness were higher in the south sector when compared with those in the other two sectors. Biotic-environmental interaction through canonical correspondence analysis (CCA) inferred that the combined effects of salinity, chlorophyll-a, and nutrient levels are the key factors responsible for the distribution of the ciliate species, suggesting that ciliates can be considered to be potential bioindicators of water quality.