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.     

Effects of cement flue dusts from a Nigerian cement plant on air, water and planktonic quality

Effects of cement flue dust from Ewekoro cement Kilns were monitored at some aquatic receptor locations. High levels of total suspended particulates (TSPs) and atmospheric deposition rates (ADRs) were recorded within the factory compared to ancillary locations outside the factory. The TSP and ADR levels which were location dependent were significantly higher (P?<?0.05) during the dry periods than in the wet season. Irrespective of seasonal variations, the key elements in the emissions were Ca^2?+? and Fe^2?+?. The concentrations of Zn^2?+?, Mn^2?+? and Pb^?+? which were trace elements were significantly higher (P?<?0.05) in the deposited than in the airborne particulates. The planktonic flora and fauna of the river systems draining the area were poor with 16 phytoplanktonic and nine zooplanktonic species. Numerically, the phytoplanktons were dominated by diatoms (Bacillariophyta) with Synedra sp. being the most abundant species. The zooplanktonic fauna dominated by rotifers had Lecane curvicornis as a regular occurrence in all the three catchment rivers. The physicochemical parameters assayed were significantly higher (P?<?0.05) in the factory effluent discharges than in water samples from each of the catchment rivers. Seasonal variations inclusive, HCO $_{3}^{-}$ , CO $_{3}^{2-}$ , Ca^2?+? and Mg^2?+? constituted the major ionic component of water samples analysed irrespective of location. Alaguntan River which receives effluents directly from the factory had significantly higher levels (P?<?0.05) of the assayed ions than the other two rivers draining the cement factory catchment areas.     

Synthesis of zinc-carboxylate metal-organic frameworks for the removal of emerging drug contaminant (amodiaquine) from aqueous solution

We herein report the removal of amodiaquine, an emerging drug contaminant from aqueous solution using [Zn2(fum)2(bpy)] and [Zn4 O(bdc)3](fum = fumaric acid; bpy =4,4-bipyridine; bdc = benzene-1,4-dicarboxylate) metal–organic frameworks(MOFs) as adsorbents. The adsorbents were characterized by elemental analysis, Fourier transform infrared(FT-IR) spectroscopy, and powder X-ray diffraction(PXRD). Adsorption process for both adsorbents were found to follow the pseudo-first-order kinetics, and the adsorption equilibrium data fitted best into the Freundlich isotherm with the R~2 values of 0.973 and0.993 obtained for [Zn_2(fum)_2(bpy)] and [Zn_4 O(bdc)_3] respectively. The maximum adsorption capacities foramodiaquine in this study were found to be 0.478 and 47.62 mg/g on the[Zn_2(fum)_2(bpy)] and [Zn_4 O(bdc)_3] MOFs respectively, and were obtained at p H of 4.3 for both adsorbents. FT-IR spectroscopy analysis of the MOFs after the adsorption process showed the presence of the drug. The results of the study showed that the prepared MOFs could be used for the removal of amodiaquine from wastewater.     

Effect of white African mineral hair dye on the activities of phosphatases and malondialdehyde level in selected tissues of albino rats

The effect of white African mineral dye Yombofita (YF) on the activities of alkaline phosphatase (ALP), acid phosphatase (ACP) and malondialdehyde (MDA) levels in the skin, liver, kidney and serum of albino rats was investigated. The chemical analysis of the dye was first carried out using solubility test, pH determination and X-ray fluorescence (XRF) elemental analysis. Six different concentrations (0.05, 0.15, 0.25, 0.5, 0.75 and 1.00%) of the dye were prepared using hydrogen peroxide (30 volume) as solvent. A total of 80 albino rats (Rattus norvegicus) were used for the study. The rats were divided into 8 groups of 10 each and were maintained on commercial feed for the period of the experiment i.e. 30 days. In group 1, the control group, the animals were applied distilled water on their heads, whereas in group 2 the vehicle i.e. hydrogen peroxide was applied. In groups 3 to 8 various concentrations of YF (white) dye ranging from 0.05, 0.15, 0.25, 0.5, 0.75 to 1.00% was applied respectively. At the end of the experiment, blood samples were collected and portions of the selected tissues were excised for the determination of ALP and ACP activities. The MDA level was also determined in the skin of experimental animals. The results revealed a significant decrease (p?p?相似文献   

Levels and speciation of heavy metals in soils of industrial Southern Nigeria

A knowledge of the total content of trace metals is not enoughto fully assess the environmental impact of polluted soils. Forthis reason, the determination of metal species in solution isimportant to evaluate their behaviour in the environment andtheir mobilization capacity. Sequential extraction procedure wasused to speciate five heavy metals (Cd, Pb, Cu, Ni and Zn) fromfour contaminated soils of Southern Nigeria into sixoperationally defined geochemical species: water soluble,enchangeable, carbonates, Fe-Mn oxide, organic and residual.Metal recoveries were within ± 10% of the independentlydetermined total Cd, Pb, Cu, Ni and Zn concentrations. The highest amount of Cd (avg. 30%) in the nonresidual fractionswas found in the exchangeable fraction, while Cu and Zn weresignificantly associated with the organic fraction. Thecarbonate fraction contained on average 14, 18.6, 12.6, 13 and11% and the residual fraction contained on average 47, 18, 33,50 and 25% of Cd, Pb, Cu, Ni and Zn respectively. Assuming thatmobility and bioavailability of these metals are related to thesolubility of the geochemical form of the metals, and that theydecrease in the order of extraction sequence, the apparentmobility and potential bioavailability for these five metals inthe soil were: Pb > Zn > Cu > Ni > Cd. The mobility indexes ofcopper and nickel correlated positively and significantly withthe total content of metals, while mobility indexes of cadmiumand zinc correlated negatively and significantly with the totalcontent of metals.     

Evaluation of geochemical characteristics and health effects of some geophagic clays southern Nigeria

The geochemical characteristics of geophagic clays from Calabar and Okon-Eket, southern Nigeria were evaluated to determine their quality and the possible health effects of their consumption. The study involved the measurement of the pH, electrical conductivity (EC) and total dissolved solids (TDS) of the slurried clay samples soaked in distilled water for 48 h using digital multi-parameters probe as well as the elemental and mineralogical analyses of twenty geophagic clay samples for elemental and mineralogical constituents using both the ICP-MS and XRD, respectively. Medical data were also mined from medical facilities within the area in addition to the administering of questionnaire to adults involved in the geophagic practices in order to determine their justification for the practice as well as their and clay preferences. Results of physicochemical measurement revealed that the pH range of the samples ranges from 3.9 to 6.9 and 6.5 to 7.0; EC 0.3–377.7 and 0.12–82.38 µS/cm; TDS 1.98–2,432.65 and 0.08–52.95 mg/L for consumed and non-consumed clay, respectively. The elemental analyses revealed that the concentration of some potential harmful elements, PHEs, exceeded the recommended dietary intake by humans. This is especially true for Cu (9.1–23 ppm), Pb (16.7–55.6 ppm), Zn (13–148 ppm), Ni (11.1–46.4 ppm), Co (1.8–21.7 ppm), Mn (16–338 ppm), As (BDL-15 ppm) and Cd (BDL-0.2 ppm). The predominant phases established in the clay samples are quartz and kaolinite, while the minor minerals were montmorillonite and muscovite in all the clay samples. Respondents revealed that capacity for relief from gastrointestinal problems believes in the curative power to cure skin infections and cultural reasons as main justification for the geophagic practices. This is, however, not in conformity with information gleaned from the medical records which still indicated that the prevalent diseases in the area still include gastrointestinal problems in addition to malaria, hypertension and cardiac failure with minor cases of respiratory tract infections. The high concentrations of the PHEs may be responsible for or contribute in part to the prevalence of hypertension, cardiac failures and gastrointestinal problems within the study areas. Though the kaolinite present in the geophagic clays makes them suitable for use as traditional antacids; however, the toxic trace element concentrations and significant quartz content will most likely mask the beneficial effects of such kaolinite.     

Differential degradation of crude oil （Bonny Light） by four Pseudomonas strains

Four hydrocarbon degraders isolated from enriched oil- and asphalt-contaminated soils in Lagos, Nigeria, were tested for their petroleum degradation potentials. All the isolates were identified as species of Pseudomonas. Pseudomonas putida P11 demonstrated a strong ability to degrade kerosene, gasoline, diesel, engine oil and crude oil while P. aeruginosa BB3 exhibited fair degradative ability on crude oil, gasoline, engine oil, anthracene and pyrene but weak on kerosene, diesel and dibenzothiophene. Pseudomonas putida WL2 and P. aeruginosa MVL1 grew on crude oil and all its cuts tested with the latter possessing similar polycyclic aromatic potentials as P11. All the strains grew logarithmically with 1–2 orders of magnitude and with generation time ranging significantly between 3.07 and 8.55 d at 0.05 level of confidence. Strains WL2 and MVL1 utilized the oil substrate best with more than 70% in 6 d experimental period, whereas the same feat was achieved by P11 in 12 d period. BB3 on the other hand degraded only 46% within 6 d. Interestingly, data obtained from gas chromatographic analysis of oil recovered from the culture fluids of MVL1 confirmed near-disappearance of major peaks (including aliphatics and aromatics) in the hydrocarbon mixture.     

Determination of selected steroid hormones in some surface water around animal farms in Cape Town using HPLC-DAD

In this study, a method for the simultaneous determination of two steroid hormones, 17β-estradiol (E2) and estriol (E3), and a hormone mimicking polycarbonate, bisphenol-A (BPA), was developed and validated. This was thereafter used for the determination of the levels of the hormones in surface water collected around some livestock farms. The sensitivity of the method allowed the LODs and LOQs of the hormones and mimic hormone in the range 1.14–2.510 and 3.42–7.53 μg/L, respectively. The results revealed wide variability in the concentrations of E2 and E3, while BPA was not detected at any of the sampling stations. The concentration of E3 ranged between <1.14 and 45.5 μg/L (N = 120) in station 2 water. The highest concentration of E2 (15.7 μg/L, N = 80) was observed in water from station 1. The varied concentrations may be connected with the nature and sources of release, inconsistencies in analyte distribution due to dynamics of water flow pattern and the physical/chemical properties of the receiving water bodies.     

Exposure to hazardous air pollutants along Oba Akran road, Lagos-Nigeria

We measured toxic air pollutants along Oba Akran road in Lagos to evaluate pedestrian exposure. PM₁₀, CO, O₃, NO₂, SO₂, CH₄, noise, wind velocity and temperature were measured simultaneously with portable analyzers. Our results showed that pedestrian exposure to PM₁₀ (with an average of 274.6 μg m⁻³ for all samples) and CO (with an average of 19.27 ppm for all samples) was relatively high. CO is a traffic-related pollutant, so the influence of the local traffic emissions on CO levels is strong. The high concentration of the PM₁₀ measured at the three environments also suggests that the traffic is a major source of ultrafine particles. The overall average concentrations for the 72-day experimental period for SO₂, NO₂ and O₃ are 101.2, 62.5 and 0.32 ppb respectively, all of which are below the US national ambient air quality standards. Strong traffic impacts can be observed from the concentrations of some of these pollutants measured in these three environments. Most clear is a reflection of diesel truck traffic activity rich in black carbon concentrations. The diurnal variation of O₃ and NO₂ also showed that NO₂ was depleted by photochemically formed O₃ during the day and replenished at night as O₃ was destroyed. A multivariate statistical analysis (Principal Component Analysis, Factor Analysis) has been applied to a set of data in order to determine the contribution of different sources. It was found that the main principal components, extracted from the air pollution data, were related to gasoline combustion, oil combustion and ozone interactions.