Investigation of the Influence of Temperature Inversions and Turbulence on Land-atmosphere Interactions for Rolling Terrain

The surface-atmosphere exchange of trace gases and energy is important as it impacts weather, climate, and air quality. The models used for estimating surface fluxes such as heat, moisture, and carbon dioxide (CO2) were designed to work best in horizontally uniform, flat terrain. This is a challenge for measuring surface fluxes in non-uniform, complex terrain as these models break down especially during stable atmospheric conditions. The complex terrain generates its own thermal circulation such as the drainage flow at nighttime. Surface heterogeneity is common in complex terrain, which is one of the factors that leads to erroneous surface fluxes estimation. The concentrations of atmospheric greenhouse gases are increasing, leading to changes in atmospheric boundary layer (ABL) dynamics as a result of the changing surface energy balance. The ABL processes are important to characterize because they are difficult to parameterize in global and regional scale atmospheric models. Empirical data can be collected using eddy covariance micrometeorological methods to measure turbulent fluxes (e.g., sensible heat, moisture, and CO2) and quantify the land-atmosphere exchange. The objectives of this work are to calculate surface fluxes for rolling terrain using observational data collected during one week in September 2014 from a monitoring site in Echo, Oregon and to investigate the log law in the ABL. The site is located in the Columbia Basin with rolling terrain, irrigated farmland, and over 100 wind turbines. The 10 m tower was placed in a small valley depression to isolate nighttime temperature inversions. This thesis presents observations of momentum, sensible heat, moisture, and CO2 fluxes from data collected at a sampling frequency of 10Hz at four heights. Results show a strong correlation between temperature inversions and CO2 flux. The log layer could not be achieved as the value of the estimated von Karman constant (~0.62) is not close to that of the accepted value of 0.41. The impact of the irrigated farmland near the measurement site was observed in the latent heat flux, where the advection of moisture was evident in the tower moisture gradient. A strong relationship was also observed between fluxes of sensible heat, latent heat, CO2, and atmospheric stability. The average nighttime CO2 concentration observed was ~407 ppm, and daytime ~388 ppm compared to the 2013 global average CO2 concentration of 395 ppm. The maximum CO2 concentration (~485 ppm) was observed on the strongest temperature inversion night. There are few uncertainties in the measurements. The manufacturer for the eddy covariance instruments (EC 150) quotes uncertainty of ± 0.1°C for temperature between -0°C-40°C. Error bars were generated on the estimated surface sensible heat flux using the standard deviation and mean values. Under the most stable atmospheric conditions, uncertainty (assumed to be the variability in the flux estimates) was close to the minimum (~± 5 W m^(-2))

Impact of effluent from Bodija abattoir on the physicochemical parameters of Oshunkaye stream in Ibadan City, Nigeria

The problem of getting quality drinking water is increasing as untreated effluents are discharged into surface water bodies. The impact of effluent from Bodija abattoir, the biggest abattoir in Ibadan, westernNigeria on the physico-chemical parameters of Oshunkaye stream was investigated. The qualities of effluent and stream water (before and after mixing with effluent) were studied using the basic water quality parameters. The ranges of the physico-chemical parameters studied were as follows: pH 6.92 –8.18, temperature 31 – 34oC, total solids 7726 – 47 630 mg/l, total suspended solids 1498 – 6803 mg/l,chemical oxygen demand 947 - 2566 mg/l, oil and grease 2500 –12590 mg/l, nitrate 62 – 159 mg/l, phosphate 142 - 180 mg/l, chloride 1052 – 1727 mg/l, lead 0.08 – 0.2 mg/l, nickel 0.18 – 0.49 mg/l, copper not detected – 0.14 mg/l, zinc 0.67 – 6.08 mg/l and cadmium (not detected). Using Prati’s et al classification of surface water quality, Oshunkaye stream fell in the class of grossly polluted water after mixing with effluent from the abattoir. While before mixing, it fell in class of slightly polluted. Hence the abattoir effluent needs to be treated before discharge into the receiving stream to reduce health hazard

Determination of lead and cadmium contents of dry cell batteries available in Nigeria

Lead and cadmium content of different brands and sizes (N=38) of dry cell batteries (zinc-carbon Leclanche systems) available in Nigeria were determined by atomic absorption spectrometry after acid digestion. The average Pb and Cd content of the dry cells are 1077.9±751.7mg/kg (Range 42-3170mg/kg) and 108.3±81.4mg/kg (Range 4.6-410mg/kg) respectively. The mean Pb and Cd contents of dry cells with metal outer cover were significantly lower (p < 0.005) than the corresponding values for dry cells with non-metallic cover. The highest Pb and Cd values were observed in dry cell batteries imported from China. Higher mean Pb and Cd value were observed in dry cells from China (1368.36 vs. 151.47mg/kg), compared to values for dry cells from Indonesia (1032 vs. 84.4mg/kg), Japan (715.2 vs. 131.48mg/kg) and Korea (1137.5 vs. 81.45). Lower Pb and Cd values were obtained in dry cells from Malaysia (709 vs. 12.5mg/kg), Spain (702 vs. 65.8mg/kg), United States (303 vs. 11.1mg/kg) and in the only surviving local brand (408 vs. 34.5mg/kg).Our study revealed that there is an urgent need to introduce an adequate well-established system for collection, separation, storage and management of municipal and industrial wastes containing primary and secondary battery wastes and similar toxic materials to halt the open burning of such wastes within inhabited areas. There is an urgent need to develop in Nigeria an appropriate technology following the principles of waste minimization and sustainable development. Journal of Applied Sciences and Environmental Management Vol. 10 (3) 2006: 37-4

Assessment of soil-pollution by slag from an automobile battery manufacturing plant in Nigeria

This study assessed heavy metals pollution of soil by slag from an automobile battery manufacturing plant in Nigeria to ascertain the potential danger they pose on the environment. 84 soil samples were randomly collected at 0 - 15 cm and 15 - 30 cm depths from the premises of the plant and an uncontaminated site as control for both dry and wet seasons. Samples were analyzed for lead, cadmium, chromium and nickel using standard analytical methods. Lead level in soil ranged from 243 to 126000 mg/kg on the premises of the manufacturing plant with about 98% of all soil samples analyzed having levels higher than 400 mg/kg permissible level for Pb in soil. Lead levels for both seasons and depths were statistically comparable (p > 0.05). Cadmium, chromium and nickel were within the permissible limits in soil. Speciation of Pb showed about 89% Pb in non residual phases implying high availability to ecological materials. Soil within the company’s premises and the environs needs to be urgently cleaned up. Key words: Heavy metals, automobile-battery, speciation, slag, pollution

Determination of selected heavy metals in inland fresh water of lower River Niger drainage in North Central Nigeria

The concentrations of some ferruginous ore associated heavy metals were determined in freshwater from River Niger. Water samples were collected from both upstream and downstream along the mainstream drainage channel, traversing past the steel production industry Ajaokuta between 2003 and 2005. The water samples were digested according to standard methods and tested for Cadmium (Cd), Manganese (Mn), Chromium (Cr), Nickel (Ni), Cupper (Cu), Zinc (Zn) and Lead (Pb) using Unicam 969atomic absorption spectrophotometer. The mean concentrations (mg/L) of heavy metals were: Mn, 3.85 ± 0.93; Zn, 2.72 ± 0.57; Cu, 2.17 ± 0.73; Cr, 2.08 ± 1.27; Ni, 0.78 ± 0.12; Cd, 0.05 ± 0.02; Pb, 0.03 ± 0.02. Theconcentration of Mn, 1.74 to 8.37 mg/L; Cu, 0.58 to 4.50 mg/L; Cd, 0.02 to 0.13 mg/L were variable and inundating. The variations in heavy metal levels between sampling stations were not significant (P &gt;0.05) with relative standard deviation from 2% for Cd and Pb to 12.7% for Cr. The order of dispersion (2 to 14%) showed that the measured metals are nearly homogenously distributed in the water with Cr, Mn, Cu and Zn having the highest concentration variations in the water samples. The concentrations of the evaluated heavy metals were within the guideline levels for freshwaters, and did not appear to have significant negative impact on the water quality.Key words: Heavy metals, freshwater, concentrations, quality, variation, distribution

Assessment of Heavy Metal Contents of End-Of-Life Computer Monitor Cathode Tubes and Plastic Casings

Development and innovation in computer technology have led to the generation of large quantities of end-of-life computing equipment with the attendant challenge of environmentally sound management, especially in developing countries. This study evaluated the heavy metal contents of the cathode ray tube (CRT) and the plastic casing of thirty (30) end-of-life computer monitors of different brands, years of manufacture (spanning 1981-2005) and countries of manufacture. The specimens were analysed for Pb, Cu, Cr, Zn, Cd, and Ni using atomic absorption spectrophotometer after acid digestion. The mean concentrations of metals in the CRTs varied widely: 1400-14300 mg/kg for Pb; 291-1750 mg/kg for Zn; &lt;0.1-129 mg/kg for Cu; &lt;0.1-15 mg/kg for Ni; &lt;0.1-16.3 mg/kg for Cr, and &lt;0.1-4.0 mg/kg for Cd. The Pb concentrations of all the CRT samples, with mean 5120±3000 mg/kg (range: 1400- 14300 mg/kg), exceeded the 1000 mg/kg Pb limit in the EU Directive on the Restriction of Hazardous Substances (RoHS) and the Total Threshold Limit Concentrations (TTLC) used by the USA Department of Toxic Substances and Control (DTSC), for characterizing waste as hazardous. For the plastic casings, the Cu and Cd concentrations in 10 % and 20 % of the samples respectively, exceeded the TTLC. The results of this study show that the CRTs are hazardous waste requiring environmentally sound management and the crude methods of management in Nigeria which include disposal at open dumpsites and surface water, as well as recycling using crude techniques are highly dangerous, exposing man and the ecosystem to toxins

Evaluation of Pb and Cu contents of selected component parts of waste personal computers

Electronic waste (e-waste) is one of the fastest growing waste streams in the world. The increasing market penetration in developing countries such as Nigeria, replacement market in developed countries and high obsolescence rate, make e-waste one of the fastest growing waste streams. Thirty five (35) units of waste computer central processing unit (CPU) and 24 units of waste computer monitors of different brands, manufacturers, year of manufacture, and model were collected from different electronic repairers’ shops in Ibadan, South-western Nigeria and investigated for the lead and copper contents. The devices were  disassembled and the printed wiring boards (PWB) of the CPUs and monitors; and the cathode ray tube (CRT) of the monitor were milled and representative samples digested with a mixture of HNO3-H2O2-HCl and analysed using Atomic Absorption Spectrophotometry (AAS). The results showed very high levels of Cu and Pb in the samples with Cu concentrations ranging from 83100-705300 mg/kg for PWB of CPUs, 39150-630300 mg/kg for PWB of monitors and 73.2-468 mg/kg for CRT. The Pb contents varied from 18060-400650 mg/kg for PWB of CPU, 8460-80850 mg/kg for PWB of monitor and 429-9900 mg/kg for CRT. The results exceeded the Toxicity Threshold Limit Concentration (TTLC) used in  characterizing wastes as toxic. The adoption of inappropriate methods in the management of these  wastes could result in environmental pollution and human exposure to toxins. Consequently, appropriate measures should be adopted to manage these wastes as hazardous wastes.Keywords: personal computers, printed wiring board, computer monitor, lead, copper

The impact of industries on surface water quality of River Ona and River Alaro in Oluyole Industrial Estate, Ibadan, Nigeria

Samples of water from two rivers (River Ona and River Alaro) in Oluyole Industrial Estate, Ibadan, Nigeria were analysed to evaluate the impact of industrial discharges on the surface water quality. The results obtained indicated that most of the parameters analysed (pH, total hardness, sulphate, chloride, nitrate and dissolved solids) were lower than the World Health Organisation (WHO) maximum permissible limit for drinking water. However, the levels of nitrate, chloride, total phosphorus, total solids and oil and grease were higher in the industrial zones than those found in the upstream of both rivers. These ranged between 3.00 – 8.55, 7.48 – 11.78, 2.14 – 3.57, 260 – 520 mg/l and 381.20 – 430.80 mg/l, respectively. Nitrate and total phosphorus which are essential nutrients for plants were the most accumulated in both rivers. The gross organic pollution indicators monitored (chemical oxygen demand and oil and grease) revealed that River Alaro was more polluted than River Ona. It was established from the results of this study that industrial discharges had negative impact on the surface water qualities of both rivers. Hence, extraction of water from both rivers for domestic and agricultural purposes requires some forms of physical and chemical treatment.Key words: River Ona, River Alaro, industrial discharges, surface water quality

Impact assessment of dumpsite leachate on the qualities of surface Water and sediment of river eku, ona-ara local government, Oyo State, Nigeria.

River Eku, a water body in Ona-Ara Local Government of Oyo State was studied to assess the impact of dumpsite leachate on the qualities of surface water and sediment of the river. The mean values for dissolved oxygen (DO) (2.3 &plusmn 1.1 mg/L), chemical oxygen demand (COD) (822 &plusmn 658 mg/L), PO43- (0.35 &plusmn0.20 mg/L), SO42- (16.45 &plusmn 2.95 mg/L) were reported for the upstream region, while the downstream mean values for the same parameters gave 3.73 &plusmn 0.56 mg/L, 911.75 &plusmn 813.36 mg/L, 0.68 &plusmn 0.42 mg/L, and 26.18 &plusmn 4.46 mg/L respectively. The dumpsite leachate was also analysed for the same parameters as for the water samples. The mean levels of some pollution parameters gave evidence of pollution in River Eku. The results obtained confirmed that the dumpsite leachate was the source of pollutants in the river. Keywords: dumpsite, leachate, pollution, impact, anthropogenic, discharg