The target of this work was to study the synthesis and characterization of pumice-supported nanoscale zero-valent iron (nZVI) and the effectiveness of nZVI coated pumice to remove copper from water. The impacts of pumice dose, pumice surface chemistry, pH, and water source on copper removal were studied. Natural pumice particles were used as granular support media and coated with nZVI. Results of nZVI coated pumice characterization showed nZVI coated successfully on pumice surface being proved with characterization methods such as SEM-EDS, XPS, and XRF. nZVI coating overwhelmed the surface chemistry properties of the underlying pumice particles. Higher surface areas and more iron content were obtained in nZVI coated pumice. nZVI coating significantly increased copper uptake compared to uncoated particles. High removal capacity has been observed for all tested pH values. Control experiments indicated that nZVI bound on pumice surfaces is stable at pH values of typical natural waters. The nZVI coated pumice was found to be effective in removing copper from waters having a wide range of specific UV absorbance (SUVA) values. Overall, the results indicated that nZVI coated pumice particles are maybe alternative adsorbents to remove copper.

In this study, electrochemical removal of methylene blue (MB) from water using commercially available and low-cost flexible graphite was investigated. The operating conditions such as initial dye concentration, initial solution pH, electrolyte dose, electrical potential, and operating time were investigated. The Box-Behnken experimental design (BBD) was used to optimize the system’s performance with the minimum number of tests possible, as well as to examine the independent variables’ impact on the removal efficiency, energy consumption, operating cost, and effluent MB concentration. The electrical potential and electrolyte dosage both improved the MB removal efficiency, since increased electrical potential facilitated production of oxidizing agents and increase in electrolyte dosage translated into an increase in electrical current transfer. As expected, MB removal efficiency increased with longer operational periods. The combined effects of operating time–electrical potential and electrical potential–electrolyte concentration improved the MB removal efficiency. The maximum removal efficiency (99.9%) and lowest operating cost (0.012 $/m 3 ) were obtained for initial pH 4, initial MB concentration 26.5 mg/L, electrolyte concentration 0.6 g/L, electrical potential 3 V, and operating time 30 min. The reaction kinetics was maximum for pH 5, and as the pH increased the reaction rates decreased. Consequent techno-economic assessment showed that electrochemical removal of MB using low-cost and versatile flexible graphite had a competitive advantage.

Cumulative health risk estimation for exposure to mixtures is a current issue, which would present a useful tool for environmental and public health management. Cumulative risks were estimated with response and dose addition methods for individual multi-route -multi-pathway exposure to trihalomethanes and associated carcinogenic toxic risks in Izmir, Turkey. Exposure levels were estimated for ingestion, dermal, and inhalation routes using measured tap water and bottled water THM concentrations. Drinking, showering, hand and dish washing were the considered pathways. THM concentrations in air during the showering were modeled with two-resistance theory using tap water concentration data. The estimated carcinogenic risk levels for ingestion route were in the range of safe (< 10 −6 ) to low priority (< 10 −4 ), for dermal route all were in the safe zone (< 10 −6 ), and for inhalation route were in the range of safe to high priority (> 10 −4 ) zones, indicating ingestion and inhalation routes were of similar significance ahead of dermal exposure. Cumulative carcinogenic risks of THM compounds were estimated using simple (response) addition and dose addition using cumulative relative potency factor (CRPF) methods. CRPF method estimated the risks at lower levels compared to the simple addition, which originated from the use two different risk factor values for the index chemical in the method. Cumulative chronic-toxic risks were also assessed, rendering below the threshold risk levels for all routes. This study showed that multi-route -multi-pathway exposure assessment and cumulative risk assessment should together be considered for better environmental and public health management.

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h i g h l i g h t s Dominant PBDE and NBFRs in PM 1 , PM 10 , and settled dust are BDE-209, BEH-TEBP, BTBPE. BFRs in PM 1 constitute~50% of those in PM 10 in studied computer repair service. BFRs measured with passive samplers higher than active sampling but similar to PM 10 . Similar gaseous and PM 1 -associated BFR exposures at~50% of PM 10 -associated levels.The results point out that health risks for the employees may be considerable.

The COVID-19 pandemic, which has reached 4 million global cases as of March 10, 2020, has become a worldwide problem. Turkey is one of the most affected (9 th in the world) country with 139 771 cases. An intermittent curfew policy that differ for three age groups, and an intercity travel ban varying within the country have been implemented. The effects of changes in social life and industrial activity in terms of environmental pollution are not yet known. The short-term effects on PM 2.5 , PM 10 , SO 2 , NO 2 , NO, NO x , O 3 and CO concentrations measured at 51 air quality measurement stations (AQMS) in 11 cities in March – April period of 2020 were statistically compared with that of the previous year. While PM 2.5 (9/14 AQMS) and PM 10 (29/35 AQMS) concentrations were not significantly affected, NO (12/24 AQMS), NO 2 (20/29 AQMS), NO X (17/25 AQMS) concentrations were decreased, SO 2 concentrations at half of the AQMSs (11/25) did not show a significant change. There were stations at which higher pollutant concentrations were measured in the study period in 2020 compared to that of 2019. Excess risks associated with PM 2.5 and PM 10 were estimated to be variable, albeit with a small difference. In conclusion, the heterogeneous actions taken in response to the COVID-19 pandemic resulted in mixed effects on ambient air quality.

This research investigates the adsorption capacity of a novel composite material, namely nano zero-valent iron coated coffee grounds (nZVI-CG), for removal of zinc (Zn) and nickel (Ni). nZVI particles were synthesized and immobilized to the surface of waste coffee grounds (CG) using the ultrasonic-assisted liquid phase method. Characterization of synthesized nZVI-CG composite and bare CG showed that nZVI coating has increased the surface area significantly. Batch tests were conducted to examine the effects of pH, reaction time and initial metal concentrations on Zn 2+ and Ni 2+ removal. At an initial metal concentration of 10 mg-Ni/L and 10 mg-Zn/L, nZVI-CG removal rates for Zn 2+ and Ni 2+ were observed as 98.89% and 97.29%, respectively; while removal rates of bare CG have remained at 51% (Zn 2+ ) and 48.1% (Ni 2+ ). Moreover, acidic conditions were observed to deteriorate Ni 2+ and Zn 2+ adsorption since most functional groups of the metals were protonated. Increasing initial nickel and zinc concentrations decreased removal rates. While the model fittings improved with increasing pH, in the case of nZVI-CG, Langmuir isotherm gave the best fits for Ni 2+ and Zn 2+ at pH 5 and 7. Also, our experimental results followed the pseudo-second-order kinetic model, regardless of the used adsorbent. Consequently, our results showed that nZVI-CG composite material is a promising alternative adsorbent for pilot scale metal removal/recovery applications.

This paper aims to review available information in the literature on the factors responsible on formation, species disinfection by-products (DBPs) and their health effects in swimming pool water. DBPs in swimming pools is significant for international literature and this review is the first study with the main focus of DBPs in swimming pool in national academic arena.Various disinfectants are applied in order to eliminate the pathogen microorganisms in drinking water distribution network and swimming pools. While chlorine based disinfectants are used commonly, also bromine based chemicals are preferential disinfectants. The sources of the organic matter precursors are; i) natural organic matter content of filling water and ii) organic loadings from swimmers. While disinfectants inactivate pathogens in swimming pools, mutagenic or carcinogenic DBPs are formed as a result of reactions between disinfectants and natural organic matter (NOM), bromide/iodide and human inputs. The formation of DBPs in swimming pool are higher than drinking water due to higher disinfectants residual and DBPs precursors. Trihalomethanes (THMs) and haloaceticacids (HAAs) are commonly observed as DBPs in swimming pools. THMs can be observed high concentration not only in swimming pool waters but also in indoor air ambition due to their volatile nature. Understanding of DBPs formation and control in swimming pools is important to minimize adverse health effects. It is much easier and cheaper to reduce DBPs before formation the pool with removal of precursors and use of proper disinfectants.