Active Mine Sites Research Articles

Regional geochemical baseline concentration of potentially toxic trace metals in the mineralized Lom Basin, East Cameroon: a tool for contamination assessment

The distribution of trace metals in active stream sediments from the mineralized Lom Basin has been evaluated. Fifty-five bottom sediments were collected and the mineralogical composition of six pulverized samples determined by XRD. The fine fraction (< 150 µm) was subjected to total digestion (HClO4 + HF + HCl) and analyzed for trace metals using a combination of ICP-MS and AAS analytical methods. Results show that the mineralogy of stream sediments is dominated by quartz (39–86%), phyllosilicates (0–45%) and feldspars (0–27%). Mean concentrations of the analyzed metals are low (e.g. As = 99.40 µg/kg, Zn = 573.24 µg/kg, V = 963.14 µg/kg and Cr = 763.93 µg/kg). Iron and Mn have significant average concentrations of 28.325 and 442 mg/kg, respectively. Background and threshold values of the trace metals were computed statistically to determine geochemical anomalies of geologic or anthropogenic origin, particularly mining activity. Factor analysis, applied on normalized data, identified three associations: Ni–Cr–V–Co–As–Se–pH, Cu–Zn–Hg–Pb–Cd–Sc and Fe–Mn. The first association is controlled by source geology and the neutral pH, the second by sulphide mineralization and the last by chemical weathering of ferromagnesian minerals. Spatial analysis reveals similar distribution trends for Co–Cr–V–Ni and Cu–Zn–Pb–Sc reflecting the lithology and sulphide mineralization in the basin. Relatively high levels of As were concordant with reported gold occurrences in the area while Fe and Mn distribution are consistent with their source from the Fe-bearing metamorphic rocks. These findings provide baseline geochemical values for common and parallel geological domains in the eastern region of Cameroon. Although this study shows that the stream sediments are not polluted, the evaluation of metal composition in environmental samples from abandoned and active mine sites for comparison and environmental health risk assessment is highly recommended.

Statistical testing of availability for mining technological systems with air quality constraints

AbstractWe develop a mining technology statistical model showing that even environmentally sustainable mining can be still very profitable. We put constraints on mining activities for elevated levels of particulate matters (eg, PM2.5 and PM10) in the air. We show that upper quantiles (eg, 95%) of productivity slightly decrease with respect to maximal number of failures, and this high‐productivity feature is robust with respect to variation of underlying statistical parameters. We illustrate the model on two currently active mining sites, the Chuquicamata copper mine in Chile and the opencast coal mine Libouš in the Czech Republic. Two generic working scenarios have been obtained. We show that, under very realistic conditions for both countries, the Czech Republic and Chilean mining companies can regulate mining activities for high thresholds of air pollutants without a substantial loss of productivity. Sensitivity analysis with respect to parameters is provided.

Perception of the Environmental Degradation of Gold Mining on Socio-Economic Variables in Eastern Cameroon, Cameroon

Artisanal mining is associated with a number of environmental impacts, including deforestation and land degradation, open pits which pose animal traps and health hazards, and heavy metals contamination of land (water and soil), dust and noise pollution. The study examines the perception of environmental degradation of gold mining sites in eastern Cameroon. Human-environment interaction and distance decay models are the conceptual framework for this study. This study employed a survey research design through the use of primary data while a purposive sampling technique was utilized. A total of 440 questionnaires were administered to selected households across the localities in the study area. Frequencies, percentages, chart, cross tabulations and chi-square tests were used for the data analysis. In other to achieve the aim of this study, a comparison between the nearby and far away residents were done. The study revealed that mining exploitations have brought about changes in the colour and taste of water in the active mining sites (41.7%). Malaria is the number one type of disease that has caused more damage in the localities (81.6%). Mining activities have successfully enabled children in the active mining sites to abandoned school for mining (75.0%). Inhabitants of unit 1 directly linked the problems facing their economic activities to inadequate arable land for agriculture (33.8%) and inhabitants across the study area correlated the problems facing livestock farming to diseases as a result of mining activities (64.6%). The perceived negative effects of gold mining on different socio-economic variables (such as culture, health, education, economy and livestock) vary significantly depending on the proximity from the mining areas (p<0.05). The study concludes that residents living within and far away from the active mining sites were affected by gold mining activities. However, the most worrisome situation concern people working and living within the active mining sites. Therefore, the study recommends that: companies that are involved in mining activities and the government should embark on development projects such as portable water, schools, hospitals, roads, markets, communications facilities in the affected communities.

Temporal and Spatial Patterns of Ship Traffic in the Canadian Arctic from 1990 to 2015 + Supplementary Appendix 1: Figs. S1–S7 (See Article Tools)

The limited availability of consistent, longitudinal data sources for marine traffic in Arctic Canada has presented significant challenges for researchers, policy makers, and planners. Temporally and spatially accurate shipping data that reveal historical and current traffic trends are vital to plan safe shipping corridors, develop infrastructure, plan and manage protected areas, and understand the potential environmental and cultural impacts of change, as well as for sovereignty and safety considerations. This study uses a recently developed geospatial database of ship traffic to provide the first synthesized overview of the spatial and temporal variability of different vessel types in Arctic Canada during the 26-year period from 1990 to 2015. This examination shows that, overall, the distance traveled by ships in Arctic Canada nearly tripled (from 364 179 km in 1990 to 918 266 km in 2015), that the largest proportion of ship traffic in the region is from general cargo vessels and government icebreakers (including research ships), and that the fastest growing vessel type by far is pleasure craft (private yachts). Spatial shifts in vessel activity over the last quarter century have favoured areas with active mine sites, as well as the southern route of the Northwest Passage. As a result, some communities, including Baker Lake, Chesterfield Inlet, Pond Inlet, and Cambridge Bay, are experiencing greater increases in ship traffic.

Expected impacts of active mining on the distribution of heavy metals in soils around Iludun-Oro and its environs, Southwestern Nigeria

This present study is aimed at evaluating the level of environmental degradation and potential ecological risk in soils around an active (tantalum-niobium) mining site of Iludun-Oro, southwestern N...

Geogenic and Anthropogenic Chromium Contamination in Groundwater in an Ophiolitic Area, Northeastern Iran

Geology of Iran shows an ophiolitic belt around the central Iran micro-continent. One of the main ophiolite suites, with ca. 100km long and 15km wide, located northeastern Iran as Sabzevar ophiolite suite. Ultramafic rocks of this ophiolite suite, display a high concentration of chromium (1000-3000ppm) as a compatible element, especially in pyroxene group minerals. Average Chromium content of this ophiolite suite in peridotites is 2558ppm, with maximum 4525ppm (in pyroxenite) and minimum 832ppm (in dunite). Dunite layers lie underneath of these ultramafic rocks, containing chromite lenses (FeCr2O4) with 20.56wt% Cr2O3. Today, about 10 active mining sites excavate ultramafic rocks for chromite ore mineral and altered ultramafic rocks, serpentinite, dump as unconsolidated gangue materials along stream pathways. There is an unconfined aquifer just southern of this ophiolite range containing detrital altered ultramafic rocks with the high concentration of chromium minerals. In this study 23 groundwater samples, collected from unconfined serpentinite alluvium aquifer that shows cumulative increasing Cr towards south because of increasing residence time, and much more water-rock interactions. Total Cr concentrations in this aquifer are from 12 to 61µg/l, higher than normal level of Cr mentioned by WHO (2µg/l). On the other hand, discharging of chromite mine and mineral processing site, contaminate one of drinking well at Forumad village up to 61µg/l of total chromium. Although trivalent Cr is an essential nutrient, in oxidation conditions with increasing Eh and pH, it changes to chromate (CrO4-2) and dichromate (Cr2O72-) as dissolved anions which will be toxic and carcinogenic in groundwater. Based on California EPA Office of Environmental Health Hazard Assessment (OEHHA), 7.2% of total Cr is hexavalent. Recent information indicates that hexavalent chromium varies from 50% to 90% of the total chromium in many water supplies.

Manganese accumulates in the brain of northern quolls (Dasyurus hallucatus) living near an active mine.

Mining is fundamental to the Australian economy, yet little is known about how potential contaminants bioaccumulate and affect wildlife living near active mining sites. Here, we show using air sampling that fine manganese dust within the respirable size range is found at levels exceeding international recommendations even 20km from manganese extraction, processing, and storage facilities on Groote Eylandt, Northern Territory. Endangered northern quolls (Dasyurus hallucatus) living near mining sites were found to have elevated manganese concentrations within their hair, testes, and in two brain regions-the neocortex and cerebellum, which are responsible for sensory perception and motor function, respectively. Accumulation in these organs has been associated with adverse reproductive and neurological effects in other species and could affect the long-term population viability of northern quolls.

A preliminary study to design a floating treatment wetland for remediating acid mine drainage-impacted water using vetiver grass (Chrysopogon zizanioides).

Acid mine drainage (AMD) is extremely acidic, sulfate-rich effluent from abandoned or active mine sites that also contain elevated levels of heavy metals. Untreated AMD can contaminate surface and groundwater and pose severe ecological risk. Both active and passive methods have been developed for AMD treatment consisting of abiotic and biological techniques. Abiotic techniques are expensive and can create large amounts of secondary wastes. Passive biological treatment mainly consists of aerobic or anaerobic constructed wetlands. While aerobic wetlands are economical, they are not effective if the pH of the AMD is <5. Anaerobic wetlands use organic-rich substrates to provide carbon source to iron- and sulfate-reducing bacteria. The efficiency of these systems declines overtime and requires continuous maintenance. Our objective is to develop an alternative, low-cost, and sustainable floating wetland treatment (FWT) system for AMD for the abandoned Tab-Simco coal mining site in Illinois using vetiver grass (Chrysopogon zizanioides). Tab-Simco AMD is highly acidic, with mean pH value of 2.64, and contains high levels of sulfate and metals. A greenhouse study was performed for a 30-day period in order to screen and optimize the necessary parameters to design a FWT system. Water quality and plant growth parameters were continuously monitored. Results show significant SO42- removal, resulting in increased pH, particularly at higher planting densities. Vetiver also helped in metal removal; high amounts of Fe, Zn, and Cu were removed, with relatively lower amounts of Pb, Al, and Ni. Iron plaque formation on the root was observed, which increased metal stabilization in root and lowered root to shoot metal translocation. Vetiver was tolerant of AMD, showing minimal change in biomass and plant growth. Results obtained are encouraging, and a large scale mesocosm study is now in progress, as the next step to develop the vetiver-based system for AMD treatment.

Removal of Ni and Zn in contaminated neutral drainage by raw and modified wood ash

ABSTRACTIn the present study, wood ash was modified by alkaline fusion, prior to hydrothermal synthesis, for potential application in the treatment of mine drainage impacted water. With this objective, two types of wood ash (both raw and modified) were evaluated for the treatment of Ni and Zn in contaminated neutral drainage (CND). Batch adsorption experiments were initially conducted on synthetic CND, and then on two real CND, sampled on two active mine sites, contaminated by either Ni (3.7 mg/L) or Zn (9.1 mg/L). Leaching of Zn was observed during the kinetic tests for the raw wood ash, whereas its modification suppressed the leaching. The cation exchange capacity acquired by modification of the two samples of wood ash exceeded 300 meq/100 g (which is two to fourfold higher than those of the raw ash), while sorption capacity for Ni and Zn tripled relative to the raw material. The Langmuir model best described the sorption process for all materials, while potential mechanisms of metal removal include adsorption, precipitation and ion exchange, following pseudo second-order kinetics. Results also showed that within 2 h of contact of mine effluents with one modified wood ash, Ni and Zn concentrations decreased below the maximum authorized monthly mean concentration allowed by the Canadian law (0.5 mg/L), whereas the other modified wood ash allowed reaching the regulatory conformity after 2 h for Ni but 7 days for Zn (although 93% removed after 2 h). Nonetheless, the pH was raised (10.9–11.8) above the legally allowed limits (6–9.5). Based on these findings, modified wood ash could be considered as a promising option for the treatment of Ni and Zn in CND, but the pH correction of final effluent might be necessary.

Climate and soil factors influencing seedling recruitment of plant species used for dryland restoration

Abstract. Land degradation affects 10–20 % of drylands globally. Intensive land use and management, large-scale disturbances such as extractive operations, and global climate change, have contributed to degradation of these systems worldwide. Restoring these damaged environments is critical to improving ecosystem services and functions, conserve biodiversity, and contribute to climate resilience, food security, and landscape sustainability. Here, we present a case study on plant species of the mining intensive semi-arid Pilbara region in Western Australia that examines the effects of climate and soil factors on the restoration of drylands. We analysed the effects of a range of rainfall and temperature scenarios and the use of alternative soil materials on seedling recruitment of key native plant species from this area. Experimental studies were conducted in controlled environment facilities where conditions simulated those found in the Pilbara. Soil from topsoil (T) stockpiles and waste materials (W) from an active mine site were mixed at different proportions (100 % T, 100 % W, and two mixes of topsoil and waste at 50 : 50 and 25 : 75 ratios) and used as growth media. Our results showed that seedling recruitment was highly dependent on soil moisture and emergence was generally higher in the topsoil, which had the highest available water content. In general, responses to the climate scenarios differed significantly among the native species which suggest that future climate scenarios of increasing drought might affect not only seedling recruitment but also diversity and structure of native plant communities. The use of waste materials from mining operations as growth media could be an alternative to the limited topsoil. However, in the early stages of plant establishment successful seedling recruitment can be challenging in the absence of water. These limitations could be overcome by using soil amendments but the cost associated to these solutions at large landscape scales needs to be assessed and proven to be economically feasible.

Magnetic susceptibility mapping of the Sudbury area, Ontario, Canada: evaluating pollution distributions decades later

This study evaluates the use of magnetic susceptibility and magnetic parameter measurements in assessing spatial and temporal variations of pollutants that emanated from mining industries in and around Sudbury, Ontario, Canada. For this purpose, in situ magnetic susceptibility (κin situ) was measured at 106 sites on a grid of 10 km × 10 km and 5 km × 5 km. The κin situ values ranged from 2 × 10−5 to 149 × 10−5 SI, and the highest κin situ values were observed near the active (Copper Cliff) and inactive (Coniston) mining sites. The lowest κin situ values were measured at increased distances from possible pollution sources; therefore, mapping of in situ magnetic susceptibility values is a proxy to polluted areas in and around Sudbury. To evaluate potential anthropogenic and (or) lithogenic input to κin situ, low-frequency mass specific magnetic susceptibility (χlf) variations with depth were classified into four different types of profiles. For further investigation of magnetic minerals in the samples, laboratory measurements of magnetic susceptibility, frequency dependence of magnetic susceptibility, hysteresis properties, thermosusceptibility curves, anhysteretic and isothermal magnetizations, and scanning electron microscopy – energy-dispersive X-ray spectroscopy (SEM–EDS) were also conducted on the soil samples. Laboratory measurements indicated that ferrimagnetic minerals (e.g., magnetite) of variable grain size were the dominant magnetic minerals, with the exception of one site that contained an iron sulfide (greigite) phase near a mine waste site. Magnetic spherules observed in SEM micrographs are of variable sizes (6–60 μm), suggesting that suspended particulate matter (PM10) is present, and may be a health concern. At some sites, EDS analysis showed that heavy metals (Co, Al, and Ni), which threaten human health, are also present in the study area.

Ecological footprint: an indicator of environmental sustainability of a surface coal mine

Ecological footprint of mining can be used as an indicator to monitor and regulate mining operations and ensure long-term environmental sustainability. It can be viewed as a mining footprint, which is surrogate of the environmental impacts of mining. In this paper, a methodological framework is developed to demonstrate how ecological footprint can be used as an indicator of environmental degradation. Nine air quality and 26 soil quality samples are collected from the adjoining area of a mechanized coal mine, located in Raniganj coal mining belt of Burdwan district, West Bengal. Geographical information system is used for data interpolation and preparation of air and soil quality maps. The weights of different air and soil quality parameters are calculated by running principal component analysis. These derived weights are used for preparation of final composite air and soil quality maps. The composite maps show the mining footprints, expressed as land equivalent, around the active mine sites. The impact zones reveal the extent of degradation of the soil and air qualities in the areas near a mine. It is found that the impact zones, with respect to air and soil qualities, extend over areas which are 7.7 and 7.8 times the actual mining areas, that is, the area covered under mining operations, respectively. The results show the extent of degradation of air and soil qualities of the area. At different stages of mining, these footprints can be used as indicators to reveal the areas where soil and air qualities are adversely impacted.

Small mammals as sentinels of oil sands related contaminants and health effects in northeastern Alberta, Canada

The extraction of bitumen in areas of northeastern Alberta (Canada) has been associated with the release of complex mixtures of metals, metalloids, and polycyclic aromatic compounds (PACs) to the environment. To mitigate effects on ecosystems, Canadian legislation mandates that disturbed areas be reclaimed to an ecologically sustainable state after active operations. However, as part of reclamation activities, exposure to, and effects on wildlife living in these areas is not generally assessed. To support successful reclamation, the development of efficient methods to assess exposure and health effects in potentially exposed wildlife is required. In the present study, we investigated the usefulness of two native mammalian species (deer mouse Peromyscus maniculatus, and meadow vole Microtus pennsylvanicus) as sentinels of oil sands related contaminants by examining biomarkers of exposure and indicators of biological costs. Tissue residues of 31 metals and metalloids in kidneys and muscle, activity of the hepatic detoxification enzyme EROD (as a biomarker of exposure to organic contaminants), body condition, and the relative mass of liver, kidney, spleen, and testes were compared in animals from one reclaimed area and a reference site. Deer mice from the reclaimed site had higher renal levels of Co, Se and Tl compared to animals from the reference site, which was associated with reduced body condition. Lower testis mass was another feature that distinguished mice from the reclaimed site in comparison to those from the reference site. One mouse and one vole from the reclaimed site also showed increased hepatic EROD activity. In marked contrast, no changes were evident for these variables in meadow voles. Our results show that deer mouse is a sensitive sentinel species and that the biomarkers and indicators used here are efficient means to detect local contamination and associated biological effects in native mammals inhabiting reclaimed areas on active oil sands mine sites. These field-derived findings can be used by risk assessors to fill possible data gaps for mammalian wildlife in science-based environmental risk assessments for oil and gas projects.

Condition evaluation of a unique mining site

The primary objective of this study was to evaluate the existing conditions and the stability of a mining site in which the unique features of seismicity, mining activity, hydrological conditions, geological conditions, environmental conditions, and future development plans were considered. In particular, the potential subsidence locations near the proposed construction site, the effects of mining boundary profile, and the influence scope of the mining activity on the neighboring areas were investigated using the finite element method. The study results indicate: (1) the overlying sandstone layer to the coal layer is the key to the stability of the mining roof; (2) the broken boundary has the most effect, followed by the arc boundary and linear boundary; (3) the safe distance from the mining boundary should be at least 400m if the proposed structure is to be built near an active mining site. Other relevant engineering recommendations are also proposed. The concluded results from this study may serve as a guide to other similar sites in the world.

Current Research on Mine Water and the Environment in New Zealand

Modern mining increasingly requires social licence to undertake all activities, from exploration through final closure. While this social licence has strong cultural, political, and economic aspects, it needs to be underpinned by scientific knowledge of its potential environmental effects, and technological approaches that can be used to resolve environmental issues. Water quality is one of the major aspects associated with obtaining social licence to mine, and the effects of that water quality on biota is a topic of growing concern with the public. In this Special Issue, we have gathered some representative papers from a 10-year multidisciplinary research programme in New Zealand aimed at understanding and mitigating mine water quality issues. The relationships between water quality and New Zealand’s unique endemic biota have been a particular focus in this research programme, but the principles behind these studies are applicable world-wide. The New Zealand mining sector occurs within a relatively young and active geological setting that gives rise to many different mineral deposit types as well as a rich mining history. The New Zealand climate is highly varied, ranging from sub-tropical through cool temperate to arid, with some mines receiving up to 6 m of rain a year, while others experience annual evaporation that exceeds precipitation. Currently, mining in New Zealand mostly focuses on alluvial, epithermal, and orogenic gold deposits; lignite, sub-bituminous, and bituminous coal deposits, and Fe-rich mineral sand. In addition, exploration and resource development programmes are underway for other types of mineral deposits. Authors have contributed research papers to this Special Issue based both on water quality datasets from active mine sites and longer term water quality issues at abandoned historic mine sites. In this Special Issue, we present mine water research with several themes:

Asteropeia mcphersonii, a potential mycorrhizal facilitator for ecological restoration in Madagascar wet tropical rainforests

Ecological restoration in severely disturbed environments can fail because of lack of knowledge of the functioning of the original ecosystem. Nevertheless, facilitating establishment between plant species can help accelerate ecological succession, especially in stressful environments. Mycorrhizal symbiosis plays a key role in plant growth, particularly in harsh environments, and could also play a role in facilitation between plants, as mycorrhizal fungi can form a mycelial network that simultaneously interacts with the root systems of several plant species. In a high-elevation Malagasy tropical rainforest on acidic and iron-rich soil surrounding an active mining site, four genera of ectomycorrhizal plants are locally abundant: Leptolaena, Sarcolaena, Uapaca and Asteropeia. A floristic survey showed that only Asteropeia seedlings can grow on bare soil. Molecular analysis of ectomycorrhizal fungi ITS rDNA enabled us to describe ectomycorrhizal communities and their distribution among these four plant genera. Russulaceae, Boletales, Cortinariaceae and Thelephoraceae are abundant in these forests. There is extensive sharing between ectomycorrhizal communities associated with Asteropeia mcphersonii and other ectomycorrhizal plants. There are also many mycorrhizal fungi species which are common to ectomycorrhizal communities of seedlings and adult trees. This abundance of generalist fungi allows us to envisage the use of A. mcphersonii in the ecological restoration of the mine site. Planting ectomycorrhizal fungi in the bare soil at the beginning of ecological restoration could allow them to grow, thereby establishing a source of inoculum to colonize other ectomycorrhizal plants and consequently facilitate their establishment.

Building a 3D model of lithological contacts and near‐mine structures in the Kevitsa mining and exploration site, Northern Finland: constraints from 2D and 3D reflection seismic data

ABSTRACTThe Kevitsa mafic–ultramafic intrusion in Northern Finland hosts a large, disseminated nickel–copper sulphide ore body. The Kevitsa intrusion is an active mining and exploration site, for which we have built a 3D model of the main lithological contacts and near‐mine structures in the area. To build the 3D model, 2D and 3D reflection seismic data have been used together with borehole data and geological map of the area. The Kevitsa reflection seismic data reveal the internal architecture of the Kevitsa intrusion and the surrounding units. For example, the seismic data have uncovered a previously unknown, deeper continuation of the Kevitsa intrusion. Improved 3D knowledge of the basal contact of the intrusion provides an exploration target for contact‐type mineralization. Within the intrusion, a limited area of strong reflections is observed in the data. This has been associated with discontinuous, smaller‐scale magmatic layering that is thought to control the extent of the Kevitsa main mineralization. Thus, our 3D model of the extents of the internal reflectors can provide a framework for near‐mine and deep exploration of the main type of mineralization in the area. In addition to exploration, the original purpose of the 3D seismic survey was geotechnical planning of the Kevitsa open‐pit mine. Accordingly, the 3D seismic data were used to create a 3D model of the subsurface structures, with a focus on the vicinity of the mine. The interpreted structures reveal a complex pattern of fault and fracture zones, some of which will be important for slope stability and operational planning of the final stages of the mine.

Assessment of the Potential of By-Product Recovery of Thorium to Satisfy Demands of a Future Thorium Fuel Cycle

A long-standing concern about the future implementation of thorium fuel cycles has been the availability of a thorium fuel cycle infrastructure, including thorium mineral recovery. Globally, while thorium is known to be a relatively abundant element, there is currently little commercial demand for thorium, leaving many of the world’s largest thorium deposits unexploited. However, adoption and subsequent expansion of the thorium fuel cycle may not require “thorium mines” because a number of mining operations (notably titanium and uranium) already extract considerable amounts of thorium, which is presently discarded. Nearly 100000 tonnes of thorium per year could be recovered from active mine sites, with most of this coming from titanium mining (˜80000 tonnes/yr of thorium) and uranium mining (˜9000 tonnes/yr of thorium). This output would be sufficient to satisfy even the most optimistic demand for thorium resources in the near future.

Linking Organic Carbon, Water Content, and Nitrous Oxide Emission in a Reclaimed Coal Mine Soil

AbstractMine‐land reclamation for biomass production is often achieved by means of large applications of N and organic C with amendments that could create soil conditions favorable for N2O production and emissions. To investigate this possibility, we conducted a laboratory experiment using mine soil collected from an active surface coal mine site near Philipsburg, Pennsylvania. During a 37‐d incubation period, we measured N2O and CO2 fluxes from non‐amended soil and from soil amended with ammonium nitrate (L + F), composted poultry manure (Comp), poultry manure alone (Man) and mixed with 3 rates of paper mill sludge (PMS) to obtain carbon to nitrogen ratios of 14, 20 and 27 (Man + PMS14, 20 and 27), each at 60% and 80% water filled pore space (WFPS). Results showed that manure alone leads to a greater emission of N2O under laboratory conditions than with L + F. However, composting manure effectively reduced the emissions compared to that of L + F despite a large addition of organic C and N. Composted manure‐treated soil emitted less than all other manure‐based treatments at both 60% and 80% WFPS. The emissions were greater from soil amended with the Man + PMS treatments compared to non‐amended and L + F‐amended soil, and it increased during periods of intense microbial activity created by the application of manure and PMS. Higher water content increased emissions particularly during periods of intense microbial activity coupled with inorganic N availability. Cumulative N2O emissions from manure‐treated soils represented less than 0·1% loss of total applied N. Copyright © 2014 John Wiley &amp; Sons, Ltd.

Assessing environmental impacts of inland sand mining in parts of Ogun State, Nigeria

Sand is a valuable resource for construction and other purposes, however sand mining often result in serious environmental problems such as land degradation, loss of agricultural lands and biodiversity, as well increased poverty among people. This study assessed the environmental impacts of inland sand mining in six selected local government areas of Ogun state, Nigeria. Twenty-seven (27) inland sand mining sites were identified, fourteen (14) of which are currently active mining site s while thirteen (13) are abandoned. The geographic location and attributes sites were captured for a spatial analysis using Geographic Information System (GIS). The sites were mapped and classified based on the severity of the damage to the ecological system. The study revealed that three of the local governments areas i.e. Abeokuta South, Ifo, Obafemi/Owode and Ado-Odo/Ota have inland sand mining sites with severe degradation, while Sagamu and Ewekoro local governments areas have inland sand mining sites that can be regarded as moderately and less degraded respectively. The intensive urban and industrial developments around these areas contributed enormously to the increased demand of sand for building and construction. Natural resources particularly, land, water quality and quantity, air quality, are the most significant impacts. Other impacts include loss of farmland, depreciation of land value, and destruction of infrastructural facilities. The study concluded that sand mining should be subject to planning and other controls in order to curtail its negative impacts. Keywords: Urbanization, Ho using, GIS, Land degradation, Sand mining, Pollution