Fuel characteristics and emissions from biomass burning and land-use change in Nigeria

Nigeria is one of the 13 low-latitude countries that have significant biomass burning activities. Biomass burning occurs in moist savanna, dry forests, and forest plantations. Fires in the forest zone are associated with slash-and-burn agriculture; the areal extent of burning is estimated to be 80% of the natural savanna. In forest plantations, close to 100% of litter is burned. Current estimates of emissions from land-use change are based on a 1976 national study and extrapolations from it. The following non-carbon dioxide (CO₂) trace gas emissions were calculated from savanna burning: methane (CH₄), 145 gigagrams (Gg); carbon monoxide (CO), 3831 Gg; nitrous oxide (N₂O), 2 Gg; and nitrogen oxides (NO_x), 49 Gg. Deforestation rates in forests and woodlands are 300 × 10³ ha (kilohectare, or kha) and 200 × kha per year, respectively. Trace gas emissions from deforestation were estimated to be 300 Gg CH₄, 2.4 Gg N₂O, and 24 Gg NO_x. CO₂ emissions from burning, decay of biomass, and long-term emissions from soil totaled 125 561 Gg. These estimates should be viewed as preliminary, because greenhouse gas emission inventories from burning, deforestation, and land-use change require two components: fuel load and emission factors. Fuel load is dependent on the areal extent of various land uses, and the biomass stocking and some of these data in Nigeria are highly uncertain.     

Determination of total petroleum hydrocarbons and heavy metals in soils within the vicinity of facilities handling refined petroleum products in Lagos metropolis

This article discusses the determination of total petroleum hydrocarbons (TPH) and heavy-metal contamination in soils within areas of refined petroleum products handling in Lagos metropolis. Soil samples were collected randomly from two petrol stations, two auto-mechanic workshops, and a National Electric Power Authority (NEPA) station. Control samples were taken from two low-density residential areas. TPH were estimated gravimetrically following standard methods of TPH analysis, while the heavy metals were determined by atomic absorption spectrophotometry. Sites studied had higher levels of TPH and heavy metals compared to the control samples. For TPH, the petrol stations have mean values of 399.83+/-106.19 and 450.83 +/- 90.58 microg/g, respectively; mechanic workshops, 362.60 +/- 185.84 and 428.55 +/- 119.00 microg/g, respectively; while the NEPA station has 356.20 +/- 210.30 microg/g compared to the control mean of 26.63 +/- 4.58. It revealed that the improper handling of refined petroleum products are potential sources of soil contamination in the sampled sites. This is indicated by the statistically significant levels of TPH and heavy metals observed between the control samples and those collected from the petroleum products handling sites. Bioremediation using microorganisms and plants is recommended.     

不同碳源条件下草菇内切型纤维素酶基因（eg1）转录表达的分析

利用Northernblot方法分析了不同碳源条件下草菇切型纤维素酶基因(eg1)的表达.结果发现,在含有纤维素的液体培养基中生长10d,eg1在草菇菌丝中有高效表达;纤维二糖、α-乳糖、β-乳糖,也能诱导eg1的表达,但和纤维素相比,eg1的表达量相对较低,并且它们的诱导效应在加入这类糖12h后迅速减弱;槐糖和龙胆二糖的诱导作用非常弱.在天然稻草为基质的固体栽培料生长时,草菇eg1的表达和草菇菌丝生长与出菇相对应,在菌丝生长期(d8)可见eg1的表达,d12时菌丝已长满,表达减弱,在出菇及菇体的分化及增大期,eg1的表达量逐渐增强,在成熟期达到最高水平;表明在草菇菇体发育中需要更多碳源及能源的补充,eg1在这方面起着非常重要的作用.图4参14     

Estimating the quantity of solid waste generation in Oyo, Nigeria.

The study established waste multipliers that could be used in conjunction with the population figure of a city to estimate the quantity of solid waste generation in the developing world. Oyo, a traditional city in Nigeria was the focus of the study. Two sets of data were collected. The first was the information on the socio-economic attributes of residents obtained from 648 households through questionnaires administered using a systematic random sampling technique. The second was the measurement of waste generated in 25% of the households for a week in each of the 12 months of the year. The study established that 23.3% of the residents surveyed have educational qualifications beyond secondary school, with 51.2% engaged in occupations requiring very little or no formal education and 50.9% were in the low-income group. The daily per capita solid waste generation was 0.129 kg. The highest (9.8%) and lowest (6.5%) of the annual quantities of waste were produced in October and February, respectively. Similarly, 20.2% of the weekly generation was produced on Saturday and the 10.2% produced on Thursday was the lowest. Animal dung, which accounted for 18.0%, constituted the highest component of the total solid waste generated. The study further established that the organic component of the waste generation was 75.4%. The results of the regression analysis R2 significant at 0.001 showed that income, household size, social status, occupation, education and season of the year explained 88.8% of waste generation in Oyo. It was established that 50.90 tonnes of solid waste was generated per day in the city in 2005, and the daily generation in the year 2008 is estimated to be 55.20 tonnes. The study concluded that with an average annual population growth of 13 000 people for the town, an additional 1.3 acres of land will need to be legally acquired annually, implying that 10.92-19.68 hectares ill be required as dump site(s) over the next 20-30 years.     

Measuring waste generation in third world cities: A case study of Ilorin,Nigeria

Problems associated with urban wastes are now at crisis stage in Nigeria. All efforts made to solve the problems have failed, as the efforts were directed towards instant cleaning rather than long lasting programs to cope with problems associated with environmental sanitation. Measurements were taken of the domestic waste generated by randomly selected households in Ilorin, to predict the generation rate for the city. The data was subjected to various analyses. The models used in developed nations were found inappropriate to predict the waste generation rate of the people at Ilorin because of cultural factors. Various methods to cope with the environmental sanitation problems of cities of developing areas were then suggested.     

Levels of natural radionuclides in some Nigerian cereals and tubers

The activities of radionuclides in the two major groups of foodstuff widely consumed in Nigeria have been determined. The 40K concentration range from 9.9+/-3.6 Bq kg-1 to 298+/-14 Bq kg-1 (av. 130+/-8.12 Bq kg-1). (238)U concentration range from 1.47+/-0.91 Bq kg-1 to 39.5+/-9.9 Bq kg-1 (av. 11.5+/-3.86 Bq kg-1), and 232Th range from 3.50+/-1.85 Bq kg-1 to 10.5+/-2.13 Bq kg-1 (av. 6.78+/-2.13 Bq kg-1). 137Cs was not detected in any of the foodstuffs analysed.     

A comparative analysis of solid waste composition and generation in two cities of a developing nation

Summary The solid wastes generated by a sample of the residents of two Nigerian cities are analysed in terms of the types of waste and the socio-economic circumstances of the residents. The types of waste produced suggest drastic modifications to the current means of waste collection and disposal, together with possible improvements in the existing forms of environmental training.Dr Adedibu is Professor of Geography at the University of Ilorin, Nigeria.     

Issues in the environmental sanitation of Lagos mainland,Nigeria

Summary Lagos is asserted to be the filthiest capital in the world. The influx of people into the metropolitan area has no corresponding technology to cope with the solid waste generated by the ever increasing population. Coupled with this lack of technology is the lack of adequate knowledge of the composition and generation rate of the refuse which has led to mismanagement of the environment. Paper waste is identified to constitute the major form of waste generated in Lagos and, in most cases, over 90 percent of the wastes generated are combustible, therefore, the use of incineration is recommended for effective management of the refuse.Dr Afolabi A. Adedibu and Mr A.A. Okekunle are members of staff in the Department of Geography at the University of Ilorin. Dr Adedibu, the senior author, has recently served as Foreign Curriculum Consultant to the Center for African Studies at the University of Florida. Dr Adedibu has presented earlier papers on Nigeria's solid waste management problems inThe Environmentalist, Vol.5, pp.123–127 and Vol.6, pp.63–68.     

Determination of polycyclic aromatic hydrocarbons in roasted coffee

Polycyclic aromatic hydrocarbons (PAHs) are suspected to be carcinogenic and mutagenic. This study describes the presence of PAHs in light, medium and dark roasted coffee including instant and decaffeinated brands. Total PAHs concentration was related to the degree of roasting with light roasted coffee showing the least and dark roasted coffee showing the highest level. Both instant and decaffeinated coffee brand showed lower levels of PAHs. Naphthalene, acenaphthylene, pyrene and chrysene were the most abundant individual isomers. The concentrations ranged from 0 to 561 ng g^?1 for naphthalene, 0 to 512 ng g^?1 for acenaphthylene, 60 to 459 ng g^?1 for pyrene and 56 to 371 ng g^?1 for chrysene. Thus, roasting conditions should be controlled to avoid the formation of PAHs due to their suspected carcinogenic and mutagenic properties.