Particulate matter concentration levels during intense haze event in an urban environment

This study assessed concentration levels of particulate matter (PM) in the ambient environment of Ilorin metropolis, Nigeria, during haze episodes. Meteorological data (wind speed and direction, rainfall data, sunshine data, relative humidity and temperature) were obtained. Aerocet 531S particle counter (MetOne Instruments, USA) was used to measure four mass concentration ranges of PM (PM_1.0, PM_2.5, PM₁₀ and the total suspended particles (TSP)) in 10 locations taking into consideration land use patterns. Surfer® version 8 (Golden Software LLC, USA) was used to model the spatial variation of particulate matter concentration levels using kriging interpolation griding method. Human exposure assessment was done using the total respiratory deposition dose (TRDD) estimates and statutory limit breach (SLB) approaches. The appearance of dominating weak southern atmospheric wind flow was observed as wind speed ranged from 0 to 6.811 m/s while solar radiation periods ranged from 0.3 to 3.5 h/day. The relative humidity of the metropolis ranged between 28 and 57%, while daily temperature was 15 to 36 °C. Highest concentration levels of PM measured were 73.4, 562.7, 7066.3 and 9907.8 μg/m³ for PM_1.0, PM_2.5, PM₁₀ and TSP, respectively. Very strong negative correlations existed between the PM concentration levels and microclimatic parameters. Spatial variation of the concentration level as modelled using Surfer® version 8 indicated that particulate concentration level increases from south to north. Concentration levels of PM for the 24-h averaging period were generally above the 24-h threshold limit value set by the regulatory agencies for all the locations.     

Are deep eutectic solvents benign or toxic?

In continuation of investigation for environmentally benign protocol for new solvents termed deep eutectic solvents (DESs), it is herein reported results concerning the toxicity and cytotoxicity of choline chloride (ChCl) based DESs with four hydrogen bond donors including glycerine, ethylene glycol, triethylene glycol and urea. The toxicity was investigated using two Gram positive bacteria Bacillus subtilis and Staphylococcus aureus, and two Gram negative bacteria Escherichia coli and Pseudomonas aeruginosa. The cytotoxicity effect was tested using the Artemia salina leach. It was found that there was no toxic effect for the tested DESs on all of the studied bacteria confirming their benign effects on these bacteria. Nevertheless, it was found that the cytotoxicity of DESs was much higher than their individual components (e.g. glycerine, ChCl) indicating that their toxicological behavior is different. For our best knowledge this is the first time that toxicity and cytotoxicity of DESs were studied. The toxicity and cytotoxicity of DESs varied depending on the structure of components. Careful usage of the terms non-toxicity and biodegradability must be considered. More investigation on this matter is required.     

Technological trends in nanosilica synthesis and utilization in advanced treatment of water and wastewater

Environmental Science and Pollution Research - Water and wastewater treatment applications stand to benefit immensely from the design and development of new materials based on silica nanoparticles...     

Annelids of a west African estuarine system

Annelids collected from eight stations in the western part of Lagos Lagoon between May, 1996 and February, 1998 were reported. Rainfall, salinity and sediment type influenced distribution of annelids, which were either dry season species, wet season species or euryhaline species. A total of fifty-five species were collected, thirty-one not recorded in earlier studies. Pollution indicators, Polydora sp., Capitella capitata, Nereis sp. and Tubifex sp. were collected in both dry and wet seasons.     

Recapitulating potential environmental and industrial applications of biomass wastes

Journal of Material Cycles and Waste Management - The generation of biomass wastes is a huge concern as they have to be properly managed to ensure environmental wellbeing. This article examined...     

Lead content in roadside vegetation as indicators of atmospheric pollution

Leaves of six plant species from 31 different locations in Ibadan, Nigeria, were analysed for their lead content. The lead concentrations found ranged between 12 and 32 μg/g, 50 m or more away from the roadside, between 47 and 115 μg/g in the residential low traffic density areas, 5 m from the roadside, and between 165 and 312 μg/g in the commercial high traffic density roadsides, 5 m away from the roadside.     

Effect of salinity on survival and growth of blue crab, Callinectes amnicola from Lagos Lagoon, Nigeria

The effect of salinity on the survival and growth of Callinectes amnicola (De Rocheburne) from the Lagos Lagoon, Nigeria was monitored in the laboratory for 22 weeks. The crabs were euryhaline and tolerated a salinity range of 5 to 25 per thousand and had 90% survival at 15 and 20 per thousand. The highest gain in weight (173.0%) and carapace width (56.1%) was obtained at salinity of 15 per thousand. The highest specific growth rate (1.98) was obtained at 15 per thousand, while the lowest specific growth rate (-0.28) was recorded at 35 per thousand. The condition factor of the crabs showed a fairly consistent pattern at the different salinity levels with values ranging from 5.7 to 7.3. Complete moulting was obtained at salinity of 15 per thousand in the 12th week of the experiment. The crab with carapace width of 6.8 cm increased to 8.1 cm (19.1%) after moulting.     

Bioaccumulation of HCH isomers in selected macroinvertebrates from the Elbe River: sources and environmental implications

Sediments of the Elbe River have been extremely polluted by contaminants originating from previous large-scale hexachlorocyclohexane (HCH) production and the application of γ-HCH (lindane) in its catchment in the second half of the twentieth century. In order to gain knowledge on bioaccumulation processes at lower trophic levels, field investigations of HCHs in macroinvertebrates were carried out along the longitudinal profile of the Elbe and tributary. Among the sites studied, concentrations in macroinvertebrates ranged within five orders of magnitude (0.01–100 μg/kg). In general, lower values of HCH isomers were observed at all Czech sites (mostly <1 μg/kg) compared with those in Germany. At the most contaminated site, Spittelwasser brook (a tributary of the Mulde), extremely high concentrations were measured (up to 234 μg/kg α-HCH and 587 μg/kg β-HCH in Hydropsychidae). In contrast, the Ob?íství site, though also influenced by HCH production facilities, showed only negligibly elevated values (mostly <1 μg/kg). Results showed that fairly high levels of α-HCH and β-HCH compared to γ-HCH can still be detected in aquatic environments of the Elbe catchment, and these concentrations are decreasing over time to a lesser extent than γ-HCH. Higher HCH concentrations in sediments in the springtime are considered to be the result of erosion and transport processes during and after spring floods, and lower concentrations at sites downstream are thought to be caused by the time lapse involved in the transportation of contaminated particles from upstream. In addition, comparison with fish (bream) data from the literature revealed no increase in tissue concentrations between invertebrates and fish.     

Intelligent modeling of dye removal by aluminized activated carbon

Environmental Science and Pollution Research - Methylene blue (MB) is an important compound in textile and wood processing industries as well as in medical research for combating malaria parasites....