Determination of Cadmium Levels in Agricultural Areas of Çarşamba and Bafra Plains

Cadmium pollution resulted from fertilizer applications were studied by determining cadmium levels in agricultural and non-agricultural soils of Bafra and Çar?amba plains. Soil samples of 68 were collected from agricultural (34) and non-agricultural (34) areas. The sample of 2 g was placed in a test tube and digested with hydrochloric acid and nitric acid mixture (3:1, v/v) in an aluminum block. Taking up the evaporated residue was dissolved in 1% nitric acid and total cadmium concentrations were determined with GF-AAS. Mean level of cadmium contents were found in agricultural areas 0.162?±?0.078 for Çar?amba and 0.433?±?0.288 mg kg^?1 for Bafra. The accuracy of the method was tested with determining cadmium contents of standard reference material and cadmium spiked soil samples.     

An engineering approach to solid waste collection system: Ibadan North as case study

This research centered on finding and perfecting methods of collection and disposal of refuse in Ibadan North Local Government Areas. The methodology used included questionnaire administration, personal interviews, field reconnaissance, and biochemical tests of water samples, all aimed at providing useful data for the design of effective methods of collecting and disposing refuse. The local government area was divided into three classes based on resident income: a high-income area (Bodija Avenue, etc.), a medium-income area (Sanngo, Oluyole, etc.), and a low-income area (Beere, Adeoyo, etc.). The research outcomes revealed that the waste generation rate for the local government ranged from 0.2 to 0.33kg/cap/day and waste density ranged from 172.41 to 217.61kg/m(3). Water analyses showed that the chloride, manganese, lead, and cadmium levels in water from low-income areas were above the WHO standard. The refuse generated in high and medium-income areas was collected and transported to the disposal site properly while only 54.5% of wastes were handled properly in low-income areas. Also, in order to make low-income areas free from wastes daily, an additional 15 metal skips and 9 refuse vehicles would be needed.     

Comparison of ALAD activities of Citrobacter and Pseudomonas strains and their usage as biomarker for Pb contamination

Delta-aminolevulinate dehydratase (ALAD) activity has been used in prokaryotes and eukaryotes as a biomarker for environmental lead (Pb) exposure and toxicity. Microorganisms are sensitive indicators of toxicity at the fundamental level of ecological organization, but bacterial biomarker studies are focused on the Pseudomonas strains in Group I and E coli. The objectives of the present work were to determine if Burkholderia gladioli belonging to group II, due to its 16SrRNA similarity, can be used as biomarker in metal contamination and compare its possible usage with Pseudomonas aeruginosa and Citrobacter freundii (previously known as Esherichia freundii) and Bacterium freundii which are classified in Group I. In this study, ALAD activity in an environmental strains of Burkholderia gladioli, Pseudomonas aeruginosa, Citrobacter freundii were investigated to evaluate potential inhibition by Pb and other toxic metals. When the ALAD activity of Burkholderia gladioli was tested, Co and Pb decreased activity by 27 and 71%, respectively. In addition to these findings, Zn increased the activity up to 26%. These effects were found to be statistically meaningful (p < 0.05). It was determined that the increase of lead concentration inhibites the ALAD activity at each of the three strains. There was a statistically significant dose–response relationship between ALAD activity in cells of Burkholderia gladioli and Pb (Pearson correlation coefficent = −0.665; r ² = 0.665, and p < 0.001). The strongest ALAD inhibition which was measured was 90% at Burkholderia gladioli when protein extracts were incubated with 750 μM of Pb. The relationship between Pb and ALAD activity was statistically described by [ALAD Activity] = 0.476−0.000597 × [Pb]. According to the obtained results, we suggest that the ALAD of Burkholderia gladioli can be used as a biomarker for lead contamination in the environment.     

Indoor/Outdoor Measurements of Volatile Organic Compounds in the Kanawha Valley of West Virginia

The Kanawha Valley region of West Virginia which is comprised of Charleston and surrounding communities Is the center of a heavily industrialized area known for its chemical manufacturing. As part of a larger study designed to investigate the Impact of the chemical industry on human exposures to volatile organic compounds (VOC), a study of the relationship between indoor and outdoor concentrations was conducted. Thirty-five homes were selected for monitoring from among volunteers; approximately ten in each of three distinct population-industry centers and four outside the Valley to act as controls. Monitoring was performed using passive, badge samplers with a three-week monitoring period. Two separate questionnaires were administered: one for characterization of the residence; and one to characterize source use during monitoring. Participants were also asked to keep a record of their activities with respect to in-home, outdoors and other Indoor environments. Analysis of the samplers was performed by solvent extraction followed by gas chromatography using a flame-ionization detector. Results suggest that indoor VOC concentrations are higher than outdoor concentrations. Additionally, certain ventilation-related parameters were identified that afforded some predictive power for indoor concentrations. No statistically significant differences between regions were identified.     

Determination of heavy metal levels in water, sediment and tissues of tench (Tinca tinca L., 1758) from Beyşehir Lake (Turkey)

In the present study, some heavy metals (Cu, Fe, Zn and Mn) were seasonally determined in water, sediment and some tissues of fish Tinca tinca from Bey?ehir Lake, which is an important bird nesting and visiting area, a water source for irrigation and drinking. In the water, Fe has the highest concentrations among the studied metals. Generally, the metal concentrations increased in the hottest period decreased in warm seasons. Results for levels in water were compared with national and international water quality guidelines, as well as literature data reported for the lakes. Fe was the highest in sediment samples, also Cu and Zn were the highest in spring, while Fe and Mn were in autumn. Among the heavy metals studied, Cu and Mn were below the detection limits in some tissues. Generally, higher concentrations of the tested metals were found in the summer and winter, compared with those during the autumn and spring seasons. High levels of heavy metals were found in liver of T. tinca, while low levels in muscle samples. Metal concentrations in the muscle of examined fish were within the safety permissible levels for human consumption. The present study shows that precautions need to be taken in order to prevent further heavy metal pollution.     

Small‐Capacity Gold Production Tests From Waste Desktop Computers

This article describes a procedure for the hydrometallurgical recovery of gold from waste computer printed circuit boards (PCBs) and central processing units (CPUs). The wastes processed within the recovery installation described in this article were derived from desktop computers, the parts of which were manually sorted to select those components found to be rich in gold content. X‐ray fluorescence measurements showed that considerable amounts of gold are contained in the “finger” terminals of the PCBs as well as in the CPUs. This article describes the chemical processes for recovering gold from these parts. In addition, the article covers the emissions control apparatus that is capable of eliminating the nitrogen oxides (NOx) and sulfur dioxide (SO2) emissions produced by the recovery process. The main costs arising from the overall procedure are for personnel utilization. Approximately 60 work hours from one worker are required to process 1.75–1.85 tons of unprocessed desktop computer waste to produce gold in the form of sediments. The quantity of gold recovered from this amount of waste computers can reach up to 35 grams with a standardized purity of 21 karats. The overall recovery procedure takes eight consecutive calendar days to accomplish.     

Investigation of Nanoparticle Additives to Biodiesel for Improvement of the Performance and Exhaust Emissions in a Compression Ignition Engine

Worldwide energy demand has been growing steadily during the past five decades and most experts believe that this trend will continue to rise. The amount of emitted harmful emission gases increases in parallel with increasing energy consumption. This increase has forced many countries to take various precautions, and various restrictions on emitted emissions have been carried. In this study, effects of addition of oxygen containing nanoparticle additives to biodiesel on fuel properties and effects on diesel engine performance and exhaust emissions were investigated. Two different nanoparticle additives, namely MgO and SiO₂, were added to biodiesel at the addition dosage of 25 and 50 ppm. Fuel properties, engine performance, and exhaust emission characteristics of obtained modified fuels were examined. As a result of this study, engine emission values NO_x and CO were decreased and engine performance values slightly increased with the addition of nanoparticle additives.     

Microwave-assisted synthesis of hydroxyapatite for the removal of lead(II) from aqueous solutions

Purpose

This study has the objective to evaluate the lead(II) removal capacity of hydroxyapatite powder synthesized by microwave as an alternative method to decrease production time and cost.

Methods

Hydroxyapatite (HA) was synthesized by a microwave-assisted precipitation method using calcium nitrate and ammonium hydrogen phosphate as calcium and phosphorus sources, respectively. X-ray diffraction and Fourier transform infrared results clearly revealed that the resulting powder was HA with high purity and crystallinity. The obtained powder was used for the removal of lead(II) from aqueous solutions. The effects of pH, amount of adsorbent, initial lead(II) concentration, and contact time were studied in batch experiments.

Results

In the adsorption experiments, maximum lead(II) retention was obtained at pH 6. Adsorption equilibrium was established after 40 min. It was found that the adsorption of lead(II) on HA was correlated well (R ²?=?0.958) with the Freundlich equation for the concentration range studied. Both ion exchange and adsorption process were thought to exist in the removal process.

Conclusions

This study indicates that easily and rapidly synthesized HA by microwave-assisted precipitation method could be used as an efficient adsorbent for removal of lead(II) from aqueous solutions.     

Evaluation of a fast wastewater odour characterisation procedure using a chemical sensor array

Sewage treatment works are one of the major sources that cause atmospheric odour pollution. The increase in the number of complaints about odour nuisance is due to the increase in environmental concerns. Unfortunately, the legislation on odour nuisance from sewage treatment works is very limited. In order to determine suitable thresholds on which to base legal standards, reliable and efficient odour measurement methods need to be defined. A chemical sensor array was developed for the purpose of measuring wastewater odour. This paper describes the development of the chemical sensor system which is specifically tuned to odours of wastewater origin and which can give an electronic measure of the wastewater odours. Odour emissions from a wastewater treatment facility were detected by using a quartz crystal microbalance (QCM) sensor array. The array consists of nine sensor elements, which were coated with different materials. In this paper, the usage of these novel instruments in the water industry was shown.