Nanoparticles functionalized ceramic membranes: fabrication,surface modification,and performance

Environmental Science and Pollution Research - Membrane technologies are used intensively for desalination and wastewater treatment. Water filtration using ceramic membranes exhibited high...     

Determination of acaricide residues in saudi arabian honey and beeswax using solid phase extraction and gas chromatography

Determination of acaricide residues of flumethrin, tau-fluvalinate, coumaphos, and amitraz in honey and beeswax was carried out using a rapid extraction method utilizing C-18 SPE cartridges and an analytical method utilizing GC with ECD, NPD, and MSD detectors for the four acaricides. Recovery percentages from the extraction method ranged from 90-102%, while the minimum detection levels ranged from 0.01-0.05 mg/kg for the acaricides. Nine of the 21 analyzed samples were found to be contaminated with the acaricides tau-fluvalinate and coumaphos. Neither flumethrin nor amitraz was detected in any of the honey or wax samples. Coumaphos was found only in honey samples in which two samples exceeded the tolerance levels set by EPA and EC regulations. It has not been detected in beeswax. Five honey samples and eight beeswax samples were found to be contaminated with tau-fluvalinate. One of the wax samples was contaminated with a relatively high residue of tau-fluvalinate and contained above 10 mg/kg.     

Seasonal variability of chlorophyll-a and oceanographic conditions in Sabah waters in relation to Asian monsoon—a remote sensing study

A study was conducted to investigate the influence of Asian monsoon on chlorophyll-a (Chl-a) content in Sabah waters and to identify the related oceanographic conditions that caused phytoplankton blooms at the eastern and western coasts of Sabah, Malaysia. A series of remote sensing measurements including surface Chl-a, sea surface temperature, sea surface height anomaly, wind speed, wind stress curl, and Ekman pumping were analyzed to study the oceanographic conditions that lead to large-scale nutrients enrichment in the surface layer. The results showed that the Chl-a content increased at the northwest coast from December to April due to strong northeasterly wind and coastal upwelling in Kota Kinabalu water. The southwest coast (Labuan water) maintained high concentrations throughout the year due to the effect of Padas River discharge during the rainy season and the changing direction of Baram River plume during the northeast monsoon (NEM). However, with the continuous supply of nutrients from the upwelling area, the high Chl-a batches were maintained at the offshore water off Labuan for a longer time during NEM. On the other side, the northeast coast illustrated a high Chl-a in Sandakan water during NEM, whereas the northern tip off Kudat did not show a pronounced change throughout the year. The southeast coast (Tawau water) was highly influenced by the direction of the surface water transport between the Sulu and Sulawesi Seas and the prevailing surface currents. The study demonstrates the presence of seasonal phytoplankton blooms in Sabah waters which will aid in forecasting the possible biological response and could further assist in marine resource managements.     

Cytotoxicity of benalaxyl,metalaxyl, and triadimefon on Chinese hamster ovary cells

The cytotoxicity of the fungicides benalaxyl, metalaxyl, and triadimefon was evaluated in vitro using the Chinese hamster ovary (CHO-K1) cell line. The midpoint cytotoxicity values of neutral red (NR) incorporation (NRI₅₀), total cellular protein content (TCP₅₀), and the methyl tetrazolium assay (MTT₅₀) were estimated. Benalaxyl was the most cytotoxic fungicide, followed by metalaxyl and triadimefon. Fetal calf serum (10%) caused a reduction in benalaxyl, metalaxyl, and triadimefon cytotoxicity by factors of 1.8, 1.3, and 1.3. The effects of sublethal concentrations (NRI₂₅) of the three fungicides on the glutathione redox cycle components glutathione S-transferase, glutathione reductase, glutathione peroxidase, and total glutathione content were studied. The ameliorative effects of extracellular glutathione (1 mmol L^?1), vitamin C (70 µmol L^?1), and vitamin E (30 µmol L^?1) were also investigated. The three antioxidants led to significant effects on the glutathione redox cycle components.     

Photodegradation of Ibuprofen,Cetirizine, and Naproxen by PAN-MWCNT/TiO<Subscript>2</Subscript>–NH<Subscript>2</Subscript> nanofiber membrane under UV light irradiation

Background

In this study, the photodegradation of three pharmaceuticals, namely Ibuprofen (IBP), Naproxen (NPX), and Cetirizine (CIZ) in aqueous media was investigated under UV irradiation. The photocatalyst used in this work consists of surface functionalized titanium dioxide (TiO₂–NH₂) nanoparticles grafted into Polyacrylonitrile (PAN)/multi-walled carbon nanotube composite nanofibers. Surface modification of the fabricated composite nanofibers was illustrated using XRD, FTIR, and SEM analyses.

Results

Sets of experiments were performed to study the effect of pharmaceuticals initial concentration (5–50 mg/L), solution pH (2–9), and irradiation time on the degradation efficiency. The results demonstrated that more than 99% degradation efficiency was obtained for IBP, CIZ, and NPX within 120, 40, and 25 min, respectively.

Conclusions

Comparatively, the photocatalytic degradation of pharmaceuticals using PAN-CNT/TiO₂–NH₂ composite nanofibers was much more efficient than with PAN/TiO₂–NH₂ composite nanofibers.

     

Compost and sulfur affect the mobilization and phyto-availability of Cd and Ni to sorghum and barnyard grass in a spiked fluvial soil

Soil reclamation via additives can cause contradictory effects on the mobilization of toxic elements in soils under dry and wet conditions. Therefore, our aim was to investigate the impact of compost and sulfur in two rates (1.25 and 2.5%) on fractionation, mobilization, and phyto-availability of cadmium (Cd) and nickel (Ni) to sorghum (dry soil) and barnyard grass (wet soil) in a fluvial soil spiked with 25 mg Cd or 200 mg Ni/kg soil. Compost decreased the solubility and mobilization of Cd (especially in dry soil) and Ni (in both soils). Sulfur increased the solubility of Cd (31% in dry soil—49% in wet soil) and Ni (4.6% in wet soil—8.7% in dry soil). Sulfur altered the carbonate fraction of Cd to the soluble fraction and the residual fraction of Cd and Ni to the non-residual fraction. Compost decreased Cd and increased Ni in sorghum, but enhanced Cd and degraded Ni in grass. Sulfur increased Cd and Ni in both plants, and the increasing rate of Cd was higher in grass than in sorghum, while Ni was higher in sorghum than in grass. These results suggest that compost can be used as an immobilizing agent for Cd in the dry soil and Ni in the wet soil; however, it might be used as mobilizing agent for Cd in the wet soil and Ni in the dry soil. Sulfur (with rate 2.5%) can be used for enhancing the phyto-extraction of Cd and Ni (especially Cd) from contaminated alkaline soils.     

Measuring technical efficiency associated with environmental investment: does market competition and risk matters in banking sector

Environmental Science and Pollution Research - This paper investigates the impact of several comprehensive risks such as credit risk, capital risk, liquidity risk, and insolvency risks on Pakistani...     

Organochlorine insecticide residues in Egyptian mothers’ milk

Two hundred ninety‐two mother's milk samples were collected during 1994 from ten Egyptian governorates representing rural, metropolitan, and newly reclaimed desert areas. The samples were analyzed for 14 organochlorine insecticides and metabolites using electron capture gas chromatography and confirmed by gas chromatography/mass spectrometry (GC/MS). The overall samples average showed that the most abundant organochlorine insecticide residues were p,p'‐DDE, α‐endosulfan, β‐HCH and, p,p’‐DDT. Residues in the range of not detectable to less than 14μg/l whole milk were recorded for α‐HCH, heptachlor, heptachlor epoxide, aldrin, dieldrin, endrin endrin aldehyde and p,p'‐DDD. The percentage of samples exceeding the acceptable daily intake for children (ADIs) set by the FAO/WHO ranged from 19% to 44% in all governorates included in the study except the governorate of Minia in which only 2.6% of the samples exceeded the ADI values. The insecticides exceeding ADI values are mostly heptachlor and heptaclor epoxide (ADI = 3.12 μg/1 whole milk).     

TEMPORAL AND SPATIAL CHARACTERIZATION OF RAINFALL OVER CENTRAL AND SOUTH FLORIDA1

requency evaluation and spatial characterization of rainfall in Central and South Florida are presented. Point frequency analysis performed at all available sites has shown that the 2‐parameter Gamma probability density function is the best model for monthly rainfall frequency over Central and South Florida. The model's parameters estimated at 145 stations were used to provide monthly rainfall estimates for 10‐ and 100‐year dry and wet return periods. Experimental and theoretical variograms computed for these estimates, as well as the Kriging estimation variance maps, show that the existing rain gage network is less capable of resolving monthly rainfall variation in the wet season than the dry season. May is the dry‐to‐wet transition month, while October is the wet‐to‐dry transition month with average rainfall of 4.5 inches. Monthly average rainfall is above 7 inches during the wet season and below 3 inches during the dry season. Two‐thirds of the annual rainfall is accumulated in the wet season. Annual average rainfall is maximum (above 60 inches) in many areas along the east coast, and is minimum (below 45 inches) in many areas over Lake Okee‐chobee and Central Florida. Rainfall maps show a changing pattern between the wet and the dry seasons. Frontal rainfall occurs in the dry season, while convective rainfall, tropical depression, and hurricanes occur in the wet season. Average rainfall is higher along the east coast area in the dry season and it is higher along the west coast area in the wet season.