Open Access Case Study

Soil Quality Changes and Quality Status: A Case Study of the Subtropical China Region Ultisol

A. C. Odunze, Wu Jinshui, Liu Shoulong, Zhu Hanhua, Ge Tida, Wang Yi, Luo Qiao

International Journal of Environment and Climate Change, Page 37-57
DOI: 10.9734/BJECC/2012/1148

Aims: To provide a soil quality assessment frame work and threshold limits for assessing soil quality in Ultisol of subtropical China region.
Study Design: Selected minimum data set for soil quality assessment and threshold limits for the study were total carbon, nitrogen, soil pH and phosphorus, biomass carbon, nitrogen and phosphorus, maize grain and fresh potato tuber yields. Soil data (2000-2010), maize grain and fresh potato yield data (2000-2009) from a long term experiment under the Institute of subtropical Agriculture, China were analyzed using the SAS statistical package and means were graphically compared to determine threshold limits for selected data set and fitted into a soil quality model.
Place and Duration of Study: The key Laboratory for Agro-ecological Processes in Subtropical Regions, Chinese Academy of Sciences; Institute of Subtropical Agriculture, Changsha, Hunan China long-term experimental site in Taoyuan county, conducted from the year 2000 to 2010.
Methodology: Soils samples at the experimental fields were obtained from depths 0-20 cm using an auger at each replicate in triplicates and homogenized to obtain a composite sub sample, air-dried, sieved through 2.0 mm to obtain samples for analysis in the Laboratory. Parameters analyzed for were organic carbon concentration, measured by the combustion method using an automated C/N analyzer (Vario MAX CN, Elemental Co., Germany) while total nitrogen was by the Kjeldahl method of ISSCAS (1978). Microbial carbon, nitrogen and phosphorus levels were determined using the chloroform-fumigation-extraction method (Jenkinson and Powlson, 1976; Vance et al., 1987; Brookes et al., 1982) and adopting the conversion factors 0.45 (Wu et al., 1990), 0.45 (Brookes et al., 1985), and 0.29 (Wu et al., 2000) respectively for the C, N and P. Extractable N and Olson P were taken from values obtained from the non fumigated soil samples. Data obtained were statistically analyzed using the SAS package for ANOVA and significant means were separated using the Duncan’s New Multiple Range Test (DNMRT). Treatment means were also matched graphically to delineate critical threshold limits between classes for each parameter. Soil quality was assessed by using the Parr et al. (1992) equation; SQ =ƒ(SP,P,E,H, ER,BD,FQ, MI); where SQ= soil quality, SP= soil properties, P = potential productivity, E=environmental factor, H= health (human/animal), ER= erodibility, BD= biodiversity, FQ= food quality and MI= management input. A score scale of 1 to 5 was used in the assessment of parameters in the model; where 1 is best and 5 is the worst condition. However, E, H, ER, FQ and MI were each scored 1.0 because the long-term experiment has an environmental component, health factor, biodiversity, food quality and management input components that are being optimally managed. Therefore SQ= f(SP, P) was used to assess quality of the Ultisol at the uplands and slope land locations.
Results: At the uplands, the practice of maize-rape/marsh residue+NK (8.54gkg-1 C, 1.0 gkg-1 N and 5.67 mgkg-1 P) treatments could be rotated with Maize-rape/nil fertilizer (7.51 gkg-1 C, 0.87 gkg-1 and 0.39 mgkg-1 P) to encourage improved soil quality by allowing for more years with soil carbon sequestration, nitrogen and phosphorus credit than years of depletion and discourage soil degradation. At the slope lands, treatments that combined application of organic and inorganic fertilizer materials [Sweet potato-rape/NP+straw (7.18 gkg-1 C, 0.88 gkg-1 N and 0.38 mgkg-1 P) and Peanut-broadbean/NP+straw (6.81 gkg-1 C, 0.86 gkg-1 N and 0.38 mgkg-1 P)] improved soil quality significantly over time by sequestering significantly higher total carbon, nitrogen and phosphorus better than sole inorganic fertilizer [Sweet potato-rape/NPK (6.52 gkg-1 C, 0.81 gkg-1 N and 0.38 mgkg-1 P)].
Conclusion: Ultisol at the upland positions had better quality (SQ1) than those at the slope (SQ2) positions. Threshold limits for nutrients, pH and yield of maize and Fresh Potato tubers in the subtropical China region Ultisol was developed.

Open Access Original Research Article

Conversion of Low Density Polyethylene (LDPE) and Polypropylene (PP) Waste Plastics into Liquid Fuel Using Thermal Cracking Process

Moinuddin Sarker, Mohammad Mamunor Rashid, Md. Sadikur Rahman, Mohammed Molla

International Journal of Environment and Climate Change, Page 1-11
DOI: 10.9734/BJECC/2012/994

In every sector of the world today energy is essential. Energy has many forms such as electricity, transportation fuel and so on. A large amount of energy is produced from crude oil, which is used to produce petroleum and petroleum to produce daily usable plastics. The solution to the above mentioned problems can be solved through the utilization of the new develop technology. This new developed technology will remove these hazardous waste plastics from the environment and convert them into eco friendly liquid fuel. The process is used to convert these waste plastics into liquid fuel creates no harmful emissions and can be produced at a very little overall cost. The thermal process utilized to break down the hydrocarbon chains of the polymers and convert them into liquid fuel. A Steel reactor with temperature range from 100 ºC to 400 ºC is utilized for the plastic thermal degradation process. The process yield about 80-90% liquid product. The experiment is conducted under a fume hood and open air system, no vacuum process is applied in this particular thermal cracking process.

Open Access Original Research Article

The Environmental Quadrupole: Forest Area, Rainfall, CO2 Emissions and Arable Production Interactions in Cameroon

Epule Terence Epule, Changhui Peng, Laurent Lepage, Zhi Chen, Balgah Sounders Nguh

International Journal of Environment and Climate Change, Page 12-27
DOI: 10.9734/BJECC/2012/1035

Aims: This paper evaluates the interactions between forest area, CO2 emissions, rainfall and arable production at a national scale in Cameroon.
Methodology: The data used for this analysis was essentially time series data for all the variables spanning the period 1961-2000. It uses regression analysis to determine the most important of these variables that affects CO2 emissions and uses correlation analysis and coefficient of determination to verify the nature of the interactions between the variables.
Results: The results show that as forest area reduces there is an increase in CO2 emissions concentration in the air in Cameroon. On the other hand, as forest area and rainfall reduce arable production also reduces but forest area is seen to be more responsible for changes in arable production than rainfall.
Conclusion: The study concludes that the interactions between CO2 and forest area, arable production and forest area seem to be the most significant while rainfall is denoted as very variable from year to year.

Open Access Original Research Article

Assessing Groundwater Vulnerability to the Activities of Artisanal Refining in Bolo and Environs, Ogu/Bolo Local Government Area of Rivers State; Nigeria

Gordon T. Amangabara, John D. Njoku

International Journal of Environment and Climate Change, Page 28-36
DOI: 10.9734/BJECC/2012/1088

Artisanal refining typically involves primitive illegal stills in which crude oil is boiled and the resultant fumes are collected, cooled and condensed in tanks to be used locally for lighting, energy or transport. The distilleries are heated on open fires fed by crude oil that is tipped into pits in the ground. As part of the oil burns away, some seeps into the ground. The waste from the process is stored in open pits thereby increasing the risk of the contamination of the environment and possibly impacting the underground aquifer. It is this concern of crude oil seeping to the groundwater that necessitated the current investigation with the sole objective of assessing the vulnerability of the aquifer to the activities of artisanal refining. Soil, water and crude oil samples from artisanal refining sites were collected according to standard procedures and transferred to the laboratory for analyses to determine their properties. An empirical method was adopted in estimating the permeability. The Kozeny – Carman equation for deriving the coefficient of permeability takes the porosity (η) into account. Using a typical soil porosity η = 0.4, mean particle size = 0.05 and mean viscosity determined from crude samples permeability estimate was calculated to be 3.6 x 10-8cm/s, infiltration was assessed using a simplified version of Darcy’s law. With a typical superficial soil permeability of 3.6 x 10-8 cm/s, depth of ponding of 0.5m, and a wetting front of 0.4m, an estimated infiltration rate of 1.15 x 10-8cm/s can be expected. Given the infiltration rate and the depth to groundwater (water table is between 3m and 8m), we calculated the time for crude oil contaminant plume to intercept the water table simply re-expressing the equation for velocity as distance/time which results in approximately 4.6 years. The character of the water from the area indicates that groundwater is already being impacted given that artisanal refining has been going on in the area since 2002.

Open Access Original Research Article

Composition of Inhalable Atmospheric Particulates in Rustenburg, South Africa

Nnenesi A. Kgabi

International Journal of Environment and Climate Change, Page 58-72
DOI: 10.9734/BJECC/2012/833

In this study, inhalable particulate matter was sampled using the TEOM series 1400a, the elemental composition of the particulate matter was determined using Scanning Electron Microscopy coupled with Energy Dispersive Spectrometer (SEM/EDS) and the concentration of particulate nitrates and sulphates was analyzed using Ion Chromatography (IC). These parameters were evaluated to obtain an estimate of the composition of inhalable particulate matter (PM10) in Rustenburg, South Africa. The toxicity was also determined in terms of ratios of toxic metals to PM10, as well as to elemental carbon, nitrates and sulphates. The components of PM10 were obtained as follows: organic, halides, sulphates, crustal metals, toxic metals, nitrates, and carbon. The main toxic metals were obtained in order of decreasing abundance as Cr>Pb>Ni>V. Seasonal variations showed high levels of PM10 and sulphates in spring and high nitrate levels in summer. The SEM/EDS showed the presence of atmospheric particles of complex composition including S, Si, Al, Mg, Ca, Pb, Fe, Cr, Ni, V, and Pb.

Open Access Original Research Article

A Mathematical Model Incorporating the Influence of Biodegradation on the Fate of a Simulated Oil Spill in a Brackish Aquatic System

Lucky O. Odokuma, Janet O. Williams

International Journal of Environment and Climate Change, Page 73-98
DOI: 10.9734/BJECC/2012/770

Aims: To address the limitation in the Nigerian Oil Spill Model (NOSM) which models biodegradation using the first order decay process in which the rate of oil biodegraded is proportional to the initial mass and an empirical decay coefficient. It does not monitor the total biomass of the microorganisms involved in biodegradation. It is not a reflection of natural systems which is a combination of first, second and third order reactions.
Study Design: Cross-sectional study.
Place and Duration of Study: Eagle Island (Brackish water) behind the Rivers State University of Science and Technology, Port Harcourt, Rivers State, Nigeria between July and September, 2009.
Methodology: Monod biodegradation kinetics is used. Crude oil serves as the substrate for microorganisms. Here, there is stimulation of the destruction of substrates, consumption of electron acceptors (oxygen, nitrate) and the growth of biomass. Substrate is biodegraded by microorganisms in the aqueous phase or by biomass present as micro colonies (Molz et al., 1986). In order to simulate this model, MATHLAB/SIMULINK was used. This powerful software package offers an array of numerical methods that can be used for modeling simulation of non-linear differential equations PLOT, amongst the main functions of MATHLAB was used.
Results: From the proposed model, it was observed that biodegradation augments when there was increase in the number of bacterial population. This was quite conspicuous in the delay of crude oil breakdown that occurred because the microorganisms that degrade the substrate must grow first of all and increase in number. When the biomass was sufficient, the crude oil was quickly biodegraded. There was growth in the biomass as the microorganisms utilized the electron acceptors (oxygen and nitrate).
Conclusion: The modification of the biodegradation component in the NOSM shows the involvement of microorganisms and use of electron acceptors which is a reflection of natural systems. This proposed model addresses the limitation in NOSM where oil biodegraded is proportional to the initial mass of oil and an empirical decay coefficient.

Open Access Original Research Article

Evidence of Organic Contamination in Urban Soils of Cotonou Town (Benin)

Nelly. C. Kèlomè, Pierre Faure, Olivier Mathieu, Jean Lévêque, Lucien Marc Oyédé

International Journal of Environment and Climate Change, Page 99-112
DOI: 10.9734/BJECC/2012/1085

In Cotonou (Benin), growth of the population leads to an excessive use of natural resources, inducing organic contaminations. Surface soils collected in the town, were extracted and fractionated by liquid chromatography in three families: aliphatic, aromatic hydrocarbons and polar fractions. Each fraction was characterized by gas chromatography-mass spectrometry. All the results show that an anthropogenic input exists (waste oils). Indeed, aliphatic hydrocarbons have specific markers emphasizing the presence of petrogenic products: UCM (unresolved complex mixture), specific distribution of pentacyclic triterpane. However, specific molecular biomarkers reveal also natural input. Nevertheless, samples from similar origins do not always have the same pattern. This fact underlines that organic sources are numerous in theses soils and imply a mixture of fingerprints. Moreover, modifications of the organic matter fingerprints with time (alteration, lixiviation…) complicate correlation between organic sources and contaminated soils.