Elemental contaminants in groundwater: A study of trace metals from residential area in the vicinity of an industrial area in Lagos, Nigeria

Groundwater (well water) from a residential area within the vicinity of an industrial estate in Lagos, Nigeria were sampled and analysed by Flame Atomic Absorption Spectroscopy for their heavy metals content. This was with a view of assessing the quality of the water, which was being used for domestic activities, especially, drinking usually without treatment. Total trace metal determination by mineral acid digestion of water samples was applied. This method proved to be better than an extractive concentration technique in the quality assurance protocols with the recovery range being 90.7 ± 0.006–97.6 ± 0.003%. Mean concentration of trace metals in water samples ranged from Fe: 0.05–0.47 mg l⁻¹; Al: 0.1–1.54 mg l⁻¹; Cu: 0.14–1.39 mg l⁻¹; Zn: 0.04–0.43 mg l⁻¹; Cd: trace–0.02 mg l⁻¹; Pb: trace–0.03 mg l⁻¹, Mn: 0.01–0.18 mg l⁻¹ and Ni: 0.02–0.11 mg l⁻¹. Physical parameters of water samples examined were within the drinking water safety limits except for conductivity. Results generally indicate the presence of heavy metal constituents in groundwater samples. Detection of metals such as cadmium and lead which have serious health implications above WHO and USEPA limits in drinking water gives cause for concern.     

京津冀都市圈休闲旅游开发研究

随着我国经济发展和旅游需求的增长，休闲旅游消费日益成为我国居民的重要消费构成。京津冀都市圈休闲旅游的发展将有助于提升生活质量，带动相关产业发展，吸引内部休闲客源，提升都市圈及内部城市旅游竞争力，改善区域生态环境。分析了京津冀都市圈经济和旅游发展状况、休闲旅游发展条件、休闲旅游需求变化及开发潜力。在此基础上，论述了休闲地开发布局及相应的策略。     

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.     

Spatial distribution of particulate matter (PM10) in Warri metropolis,Nigeria

This study examined the spatial distribution of particulate air pollution in the Warri metropolis. This was done to ascertain the differences between the distribution of particulate matter (PM10) in the urban area and the surrounding rural areas. To achieve this, the study generated data from field measurement of PM10 levels for the year 2003. Analysis of variance, the U-test, and simple regression statistical techniques were used to analyze the data. The major finding of the study was that the Warri metropolitan area is polluted with PM10 levels of over 126 μg/m³, which is 81% over the 70 μg/m³ threshold of the World Health Organization. However the built-up area of the Warri metropolis is 150% more polluted with PM10 particulates than the surrounding rural areas. While the traffic-clogged area of Enerhen, Jakpa, Deco, and Estate Junctions are the most polluted areas with levels of 151 μg/m³, traditional areas had the lowest levels of 128 μg/m³. The daily distribution of PM10 showed that Mondays were the most polluted days with levels of 145 μg/m³ and Fridays were the least polluted days with levels of 141.5 μg/m³ in the built-up area, whereas in the rural area Wednesdays were the most polluted days with levels of 57.1 μg/m³ and Sundays were the least polluted days with levels of 53.5 μg/m³. Mondays generally recorded the highest PM10 values because of the large amount of industrial operation, heavy vehicular traffic in the peak period, and increased commercial activities. The study also showed significant variation in the level of PM10 particulates within the urban areas of the Warri metropolis with a calculated F-value (3.29), which is greater than the critical F-value of 3.14 at the 0.05 significance level. It is therefore recommended that urban environmental management policy should be vigorously pursued to curb the adverse consequences of increased PM10 levels in urban areas of the Warri metropolis.     

Distribution of heavy metals in sediments of Igbede, Ojo and Ojora rivers of Lagos, Nigeria

The distribution of some heavy metals, namely Cd, Pb, Zn, Fe, Cu, Cr and Mn in epipellic sediments of Igbede, Ojo and Ojora rivers of Lagos was studied weekly in the early summer (November) of 2003. The levels of selected trace metals were determined using Atomic Absorption Spectrophotometer (UNICAM 969 AAS SOLAR). Trends in heavy metal burdens in the sediments revealed weekly variations in all the rivers assessed. Statistical analyses also showed different mean levels of trace metals in the aquatic environments, the distribution of which followed the sequence Fe > Zn > Mn > Pb > Cu > Cr > Cd, Fe > Zn > Cu > Mn > Pb > Cr > Cd and Fe > Zn > Mn > Cu > Cr > Pb > Cd in Igbede, Ojo and Ojora rivers respectively. Fe recorded the highest concentration levels (1,582.95 ± 96.57 μ g/g–1,910.34 ± 723.19 μ g/g) in all the sediments investigated while the Cd levels (0.06 ± 0.10 μ g/g–0.47 ± 0.36 μ g/g) were the lowest. Expectedly, trace metal concentrations in fine grain muddy sediments of the Igbede and Ojo coastline were much higher than those of Ojora which consist of coarse and sandy deposits covering the near shore area. Generally, the results obtained fell within tolerable limits stipulated by World Health Organization (WHO).     

Public Perception of Flood Hazard in the Niger Delta,Nigeria

Summary Our study had the aim of understanding how floodplain dwellers regard the risk of flooding. About 500 questionnaires were administered to landowners in the selected settlements in the study area using systematic random sampling. The results of analysis show, among other things, that the population regards most important the causes of floods as heavy, prolonged rainfall and river overflow. Nevertheless, they have little knowledge of the frequency of severe floods, and flood alleviation schemes. Most flood victims do not get compensation or relief during flood disaster, and the reason why they remain in the study area is influenced by their occupations, especially fishing, subsistence agriculture, and the presence of crude oil in the region which has attracted many migrants who cannot afford the high cost of accommodation and are therefore forced to live in vulnerable areas of the floodplain. Finally, the study concludes that flood control in the region needs the cooperation of government, community efforts and an enlightenment programmes through environmental education and mass media.     

秸秆收贮利用体系建设的困境与政策建议

我国拥有丰富的秸秆资源,但秸秆资源的利用效率很低,主要原因是秸秆收贮利用体系建设严重滞后。加强秸秆收贮利用体系建设,应强化政府对秸秆收贮利用体系建设的规范和引导,整合秸秆收贮利用各环节的相关资源,并拓宽秸秆利用企业的融资渠道。     

Value reclamation from informal municipal solid waste management: green neoliberalism and inclusive development in Lagos,Nigeria

ABSTRACT

Lagos is undoubtedly the cultural capital and economic hub of the West African sub-region. The challenge of municipal solid waste management (MSWM) in the megacity has remained intractable due partly to the increasing rate of population growth. While solid waste policy reforms, investments, and management practices in Lagos are in the upswing in the formal economy, the role of the informal economy in engendering sub-regional material linkages and livelihoods remain unexplored. Adopting a multi-stakeholder approach and data from interviews, this study critically examines how value reclamation from informal MSWM advances green neoliberalism and inclusive development. It shows that while informal transboundary trade of recyclable materials in the West African sub-region have previously been left out of analyses of MSWM in Lagos, the informal economy of waste and new investments in MSWM have neoliberal underpinnings beyond the megacity scale. The paper concludes that integrating the informal economy in framing MSWM policy in the megacity offers scope for evolving an inclusive development strategy while also enabling sustainable MSWM in the post-2015 era.     

Non-linear incentives,plan design,and flood mitigation: the case of the Federal Emergency Management Agency's community rating system

A basic proposition of ‘agency theory’ is that output-based performance incentives encourage greater effort. However, studies find that incentive schemes can distort effort if rewards for performance are discrete or non-linear. The Federal Emergency Management Agency's (FEMA) Community Rating System (CRS) is a flood mitigation programme with a non-linear incentive design. Under this programme, localities are incentivised to implement a mix of 18 flood mitigation activities. Each activity is performance scored, with accumulated scores corresponding to a percent discount on flood insurance premiums for residents that hold National Flood Insurance policies. Discounts range from 0 to 45% and increase discretely in increments of 5%. With multivariate statistical and Geographic Information Systems analytic techniques, tests are made to find whether observed changes in annual CRS scores for participating localities in Florida are explained by non-linear incentives, adjusting for hydrologic conditions, flood disaster histories, socio-economic and human capital controls that can plausibly account for local mitigation activity scores over time. Results indicate that local jurisdictions are discount-seeking, with mitigation efforts partially driven by the non-linear incentive design of the CRS programme. The paper ends with recommendations to improve the operation FEMA's flood mitigation programme.     

Impact of intensive market gardening on the nutrient status of hydromorphic soil in the Ojo area of Lagos metropolis,Nigeria

Summary This study evaluates the impact of intensive market gardening on the nutrient status of hydromorphic soil in the Ojo area of Lagos metropolis. Following 15–20 years of continuous market gardening, the organic matter content of the 0–10 cm layer of the hydromorphic soil has been reduced to 75 percent of the level found in a swamp forest soil used as a control. The extent of the organic matter decline in the cultivated soil is slight compared with the degree of organic matter diminution in well-drained soil used for shifting or continuous cultivation. This is due to the low degree of humus mineralisation in water-logged soil and the application of organic manure.In spite of regular application of both organic and inorganic fertilisers, the levels of exchangeable calcium, magnesium, potassium and sodium are lower in the 0–10 cm and 10–20 cm layers of the intensively cultivated hydromorphic soil used for market gardening than in the swamp forest control areas. The mean level of extractable manganese is lower in the 10–20 cm layer of the cultivated soil. These differences are due to nutrient immobilisation and removal in harvested vegetables, and to nutrient loss from the market gardening plots through erosion. There is, however, a build-up of available phosphorus in the surface layer of the market garden soil due to the application of inorganic phosphate fertilisers.The levels of mineral nutrients in the surface layers of the cultivated soil are within the optimal ranges for most arable crops, suggesting that the soil is not impoverished. This is due to the judicious application of both organic and inorganic fertilisers, and is indicative of the fact that hydromorphic soils can support continuous cultivation under proper management.Dr A.O. Aweto is a Senior Lecturer in the Department of Geography, and Mr G.M. Ogurie was until recently a geography student in the same department.     

新疆建筑材料用原料及其建材产品的辐射水平

报道了分布在新疆雏吾尔自治区15个地州市100多个厂矿的建筑材料用原料及其建材产品的放射性检测结果。多数建材用原料及产品的放射性水平低于国家规定的限制(控制)标准，对公众是安全的；少数地区部分建材的放射性高于限制标准，不能用作建材。必须健全对建材的放射性检测和管理制度。     

Living on the edge of stagnant water: An assessment of environmental impacts of construction-phase drainage congestion along Dhaka city flood control embankment,Bangladesh

Environmental impacts of the construction-phase drainage congestion along the Dhaka City Flood Control Embankment were assessed by a pilot questionnaire survey (in 1991) among the target population adjacent to the embankment. The results of the survey indicated that, despite significant alleviation of river flooding, the majority of the respondents experienced a new type of flood problem in the form of stagnant water inside the embankment, immediately following its construction. Not only had this stagnant water flooded and damaged their property, it had exposed them to a number of other environmental problems, such as accumulation of municipal sewage, foul odors, mosquitoes, and growth of water hyacinth. The study found that the respondents' assessments of these environmental problems differed significantly according to the magnitude of the impact of stagnant water upon two subgroups within the target population. A postsurvey follow-up in 1994 indicated that this problem of drainage congestion had largely been alleviated by completing the construction of a number of drainage regulators. The study concludes by stressing the importance of synchronizing the construction of drainage structures with that of the embankment systems and by underlining policy implications for flood-vulnerable land use adjacent to embankments.     

成都市区高层建筑电磁环境现状调查分析

由于城镇化进程的需要,越来越多的高层建筑出现在城市里,承担了我们的工作、居家、休闲娱乐的功能。随着公众环境意识逐步增强,高层建筑的电磁环境现状已成为公众关注的焦点。本文针对成都市区的高层建筑的电磁环境现状进行了调查分析。     

Heavy metal distribution in crab (<Emphasis Type="Italic">Callinectes amnicola</Emphasis>) living on the shores of Ojo Rivers,Lagos, Nigeria

Crab samples, both male and female specie, were purchased from fishermen at the Ojo Rivers, Lagos, Nigeria. The samples separated into abdomen, muscle tissue, and thorax were oven dried at 80°C for 3 days. The dried samples were then pulverized in a clean acid-washed mortar and pestle. Approximately 1.00 g each of the pulverized samples was weighed and Zn, Cr, Pb, and Cd were determined in the solution of the aqua regia digested samples by means of AAS (Buck Scientific 210 GVP model). The results obtained showed Zn metal to be consistently higher in all the female parts compared to the male with values of 12.92 ± 3.65 μg/g to 16.03 ± 1.08 μg/g and 9.33 ± 1.77 μg/g to 15.75 ± 1.02 μg/g, respectively. Mean values of 0.39 ± 0.09 μg/g and 0.22 ± 0.02 μg/g cadmium were found in the abdomen and tissue of the male crab as against 0.35 ± 0.07 μg/g and 0.17 ± 0.07 μg/g in the female crab. The tissues of both species have comparable value of chromium. Lead was below the detection limit of 0.05 μg/g in the tissues of male crab but the female tissue contained 0.83 ± 0.13 μg/g and in other parts identified, lead was consistently higher than the 2.00 μg/g permissible level of WHO in foods. A simple pair t-test did not demonstrate any significant difference in the distribution of metals between the male and female crabs. The coefficient of variation (CV) calculated for each metal with respect to the studied parts showed Pb to be widely distributed (56.23–89.54%) while Cr did not vary widely (4.17–8.20%).     

浅谈建筑施工噪声的网络化管理

通过《南宁市环境信息综合管理系统》中建筑施工噪声管理子系统的重点研究和建设,对建设施工项目审批、中午夜间施工许可登记及施工噪声投诉实时监控,加强监督,改善了管理环节,提高了管理效能,取得了良好的效果。     

日本建筑垃圾再资源化相关法规介绍

介绍了日本建筑垃圾的分类方法和种类以及与建筑垃圾再资源化有关的法律法规。     

建设用地监管数据地理本体构建方法

针对建设用地监管数据多源异构特性,难以实现语义级数据集成共享的技术问题,开展建设用地监管数据地理本体构建技术研究,提出由地理概念类、地理属性、地理关系、地理实例、地理公理构成的五元组地理本体模型,面向地理信息领域特点和建设用地监管数据内容构建建设用地监管数据本体体系,提出建设用地监管数据地理本体构建方法,利用该模型和方法实现土地利用地类地理本体的构建,为实现建设用地监管数据基于数据语义级集成奠定基础.     

Rehabilitation of a lowland river: Reconciling flood defence with habitat diversity and geomorphological sustainability

Geomorphologically appropriate rehabilitation measures were proposed to enhance the in-stream environment of the lowland River Idle, north Nottinghamshire, UK. However, the River Idle has multi-functional management requirements including those of flood defence so environmental enhancement must be pursued without significantly increasing the flood risk. Hydraulic testing of rehabilitation proposals is complicated because of the stringent assumptions about flow and morphology in ‘traditional’ hydraulic models. While new generation two- and three-dimension hydraulic models may overcome some of these problems, they are extremely data intensive, require advanced modelling capabilities and are, therefore, very expensive to apply. Also, they do not yet predict morphology-flow interactions adequately. As an alternative, several simple hydraulic models were applied to test the rehabilitation proposals, based on a fitness-for-purpose criterion.BENDFLOW was applied to fine tune the optimal siting of measures and to estimate the additional near-bank scour generated by proposed bend re-profiling. HMODEL2 and the FCFA method were used to test the impact on local channel conveyance capacities and HECRAS was applied to simulate the impact of the proposals on regional flood defence. Indicative results from the testing suggested a maximum increase in near-bank scour of 0·15 m in re-profiled bends, a loss of approximately 10% in flood conveyance locally due to deflector installation or reed and tree planting, and a 0·12 m increase in flood stage within the reach for a 15 year flood. The modelling results were acceptable to the management authority as an indication of an acceptable compromise between flood defence and conservation interests, and construction of the measures followed in 1996. It is clearly that it will require the results of post-project monitoring to indicate whether compromises made to the rehabilitation initiatives in order to satisfy flood defence requirements have unduly reduced their environmental enhancement potential but, for assessing the proposed methods, the models are recommended for use other lowland river environments.     

城镇建设用地需求预测与配置研究

针对我国现行城镇建设用地预测方法存在的问题，对城镇建设用地预测方法进行了探索性研究；通过构建科学的建设用地需求预测方法，为土地利用规划提供科学依据。在C—D生产函数的基础上，提出了土地、资本与产出GDP的要素关系模型、恩格尔系数与人均建设用地面积关系模型和时间序列的ARIMA建设用地模型。对成都市城镇建设用地总量进行了实证分析，对4种预测方法的结果进行了定量评价，并据此提出成都市建设用地的配置方案。     

Perceptions and attitudes towards gas flaring in the Niger Delta,Nigeria

Gas flaring is the burning of crude oil’s associated gas. In Nigeria’s Niger Delta, the flaring process is usually very close to communities and their farmlands and has been implicated in serious environmental degradation of the region. Studies have suggested links between gas flaring and health problems in the communities and others have established relationships between gas flaring and poor agricultural yields. This study explores how the people in the region perceive gas flaring and what their attitudes are toward it. Ubeji town, a community where gas flaring takes place, was selected as a case study. It was found that the residents perceive gas flaring as hazardous to health, environment, and general well-being of the community. Most residents seem to be resigned to the continued presence of gas flaring activities in the community. The study, however, raised several questions on modeling perception and attitudes toward environmental problems in areas where political tension and economic adversity are prevalent.