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The commercial imidacloprid (IMD) insecticide [1-(6-chloro-3-pyridinyl) methyl-4,5-dihydro-N-nitro-1H-imidazole-2-amine] is widely used for the enhancement of crop production, but the intensive use of this insecticide has caused serious environmental problems. This work presents an electrochemical process for the removal of this insecticide using galvanostatic electrolysis at modified tantalum surface by lead dioxide film anode (Ta(PbO2)) anode. The electrolytic process was monitored by chemical oxygen demand (COD). The influence of operating parameters, such as current density, initial concentration of IMD, temperature and initial pH value was investigated. The COD decay follows a pseudo first-order kinetic and the process was under mass transport control. COD removal reach 97% when using an apparent current density of 100 mA cm−2, initial COD of 953 mg L−1 and at 25 °C after 4.5 h electrolysis time.

Different aquatic ecological zones exhibit different gradients present heterogeneous algal composition. The algal community in the water column and sediment with certain environmental factors were screened monthly for twelve months with standard methods, to ascertain disparate in algal distinction. Air and water temperature, conductivity, water depth, dissolved oxygen and nutrients were the primary factors that influenced the algal abundances and diversities. 90% of the algal communities were benthic (33 species) and planktic-benthic (21) with 10% truly planktonic (6) species. Comparatively, the water-column benthic and planktic-benthic surpasses the benthic species associated with the sediment. The PCA on the habitat- type abundance revealed that 99.5% benthic algae in the water column are responsible for the total algal- abundance variance. Species richness and Shannon diversity indices were low, which ANCOVA and Levene tests demonstrated significantly equal and homogeneity of algae respectively between the studied zones. The linear relationships between the algae in the water and sediment zones were non-significant (p>0.05). The Euclidean algorithm confirmed algal community similarity in the water column and sediment. Species diversity limits, a high proportion of benthic algae in the planktonic, and significant homogenous algae in water and sediment. Signatures sediment destruction, breaking and dislodgement and uplifting of associated bottom algae, and the constant mixing of the water column and sediment due to sand dredging in the study area. Machines and human-dredging has exacerbated the abundance of benthic algae in the water column.

The aim of this study was to evaluate the mercury removal from aqueous solutions by using L-Cysteine functionalized Multi-walled Carbon Nanotubes. The effect of pH, adsorbent dose, contact time and mercury concentration in removal efficiency was evaluated. Multi -walled carbon nanotubes were functionalized with L-cysteine. The Response Surface Methodology (RSM) was used to find the optimum process parameters. The results showed that an increase in contact time, pH and adsorbent dosage resulted in an increase of the adsorption rate. However, removal efficiency decreases by increasing mercury concentration. The highest and lowest removal efficiencies of mercury were 89% and 17%, respectively. The maximum adsorption rate was occurring at 120 min. It is concluded that L-Cysteine functionalized multi-walled carbon nanotubes is an effective adsorbent for removal from aqueous solutions.

Recent studies have indicated that PAEs (phthalic acid esters) are significant environmental pollutants with carcinogenic, teratogenic, and mutagenic effects. Urban soils can act as both a source and sink for city contaminants. This paper takes Changji, Xinjiang in Northwest China as the study area and explores the pollution characteristics and health risks of PAEs in the urban soils of arid areas. The analysis results indicate average concentration occurrences of 13.77 mg/kg and ranges from 0.29 to 119.72 mg/kg in the study area. Dibutyl phthalate (DBP) and di-(2-ethylhexyl) phthalate (DEHP) were the predominant PAEs in the urban soil of Changji. The highest average PAEs concentration appeared in winter, followed by autumn and spring and the lowest in summer; the seasonal variation was significant. The climate characteristics of arid regions and seasonal variations of source emissions were the primary influencing factors. The theoretical values of the non-carcinogenic and carcinogenic risk of PAEs were relatively small, all within the acceptable range. Values of non-carcinogenic risk and carcinogenic risk to children were much higher than the risks to adults. Children were the vulnerable groups most at risk for harmful pollutants, and the safety of their living environment should be the focus of more attention.