A study to determine whether Radiological Impact Assessment (RIA) is needed for landfill disposal of treated sludge (slag) from oil and gas industries has been carried out. Radioactivity level of slag and soil samples have been measured using gamma spectrometry system and its Total Activity Concentration (TAC) has been calculated. It was found that TAC (inclusive background) was within the control limit set by the AELB i.e. 3 Bq/g as stipulated in LEM/TEK 58 (AELB, 2009). Therefore, as a result from this study, RIA is not required and the allocated area can be used for the landfill disposal of treated sludge (slag).
Sarawak has experienced several earthquakes of local origin and was also affected by long-distance earthquake that originated from Southern Philippine and the Straits of Macassar, Sulu Sea and Celebes Sea. The objectives for this study were to conduct site specific ground response analysis and develop design response spectra for Bakun area by using 1-D equivalent linear ground response analysis. The site characterisation was carried out utilising the soil profile and soil property data of the selected site. Local surface fault ruptures were investigated for possible hazards due to intraplate earthquakes. Earthquake ground motion records were selected based on characteristics of the controlling earthquakes for an area and the maximum magnitude faults were considered for risk assessment. The site-specific response spectra represent the predicted surface ground motions that reflect the levels of strong motion amplitude and frequency content at a particular site. The site-specific ground response analysis for Bakun site found that the peak ground acceleration at bedrock was amplified from 0.16 g to 0.33 g at the ground surface.
Urbanisation increases the level of imperviousness in a catchment, and more runoff is converted from rainfall in urban areas. To mitigate this adverse situation, dispensed green infrastructure presents the best solution for delivering results in reducing stormwater impact. Green roofs and rain gardens are extensively studied and widely available in the literature, but this is not the case for green walls, which more often than not, are treated as ornaments. Thus, this study developed a computer-aided stormwater model that incorporates a green wall to investigate its effectiveness as an urban drainage system. The effectiveness of employing a green wall as a stormwater component is tested using USEPA SWMM 5.1 and the embedded bioretention cell interface. Four simulation models according to different conditions and precipitation input are tested, compared and discussed. The conditions include investigation of different soil types, average recurrence interval (ARI) and storm duration with design and observed rainfall. The results reveal that synthesis precipitation data, used in Scenario 1, 2 and 3, decreased runoff by more than half, at 55% on condition of one-year ARI and 5 minutes of storm duration. Meanwhile, Scenario 4 also shows a repetition of runoff reduction by half after the integration of the green wall using the observed rainfall data. Thus, it is verified that a green wall can be effectively used as an urban drainage system in reducing surface runoff.
Tropical peatlands are globally important ecosystems with high C storage and are endangered by anthropogenic disturbances. Microbes in peatlands play an important role in sustaining the functions of peatlands as a C sink, yet their characteristics in these habitats are poorly understood. This research aimed to elucidate the responses of these complex ecosystems to disturbance by exploring greenhouse gas (GHG) emissions, nutrient contents, soil microbial communities and the functional interactions between these components in a primary and secondary peat swamp forest in Peninsular Malaysia. GHG measurements using closed chambers, and peat sampling were carried out in both wet and dry seasons. Microbial community phenotypes and nutrient content were determined using phospholipid fatty acid (PLFA) and inductively-coupled plasma mass spectrometry (ICP-MS) analyses respectively. CO2 emissions in the secondary peat swamp forest were > 50% higher than in the primary forest. CH4 emission rates were ca. 2 mg m-2 h-1 in the primary forest but the secondary forest was a CH4 sink, showing no seasonal variations in GHG emissions. Almost all the nutrient concentrations were significantly lower in the secondary forest, postulated to be due to nutrient leaching via drainage and higher rates of decomposition. Cu and Mo concentrations were negatively correlated with CO2 and CH4 emissions respectively. Microbial community structure was overwhelmingly dominated by bacteria in both forest types, however it was highly sensitive to land-use change and season. Gram-positive and Gram-negative relative abundance were positively correlated with CO2 and CH4 emissions respectively. Drainage related disturbances increased CO2 emissions, by reducing the nutrient content including some with known antimicrobial properties (Cu & Na) and by favouring Gram-positive bacteria over Gram-negative bacteria. These results suggest that the biogeochemistry of secondary peat swamp forest is fundamentally different from that of primary peat swamp forest, and these differences have significant functional impacts on their respective environments.
Global patterns of biodiversity have emerged for soil microorganisms, plants and animals, and the extraordinary significance of microbial functions in ecosystems is also well established. Virtually unknown, however, are large-scale patterns of microbial diversity in freshwaters, although these aquatic ecosystems are hotspots of biodiversity and biogeochemical processes. Here we report on the first large-scale study of biodiversity of leaf-litter fungi in streams along a latitudinal gradient unravelled by Illumina sequencing. The study is based on fungal communities colonizing standardized plant litter in 19 globally distributed stream locations between 69°N and 44°S. Fungal richness suggests a hump-shaped distribution along the latitudinal gradient. Strikingly, community composition of fungi was more clearly related to thermal preferences than to biogeography. Our results suggest that identifying differences in key environmental drivers, such as temperature, among taxa and ecosystem types is critical to unravel the global patterns of aquatic fungal diversity.
The primary biological treatment method for organic sludge is composting and/or anaerobic digestion, but their product (compost or biogas) is of little economic benefit; therefore, an improved process to produce a high-value product is required to make sludge management more sustainable. Maximizing NH3 gas recovery during composting processes has the potential benefit of producing high-value microalgal biomass. However, the majority of produced ammonia does not evaporate as NH3 gas but retains as NH4+-N in the compost after fermentation. The present study investigates the effects of the timing of Ca(OH)2 dosing (on days 2, 5, and 9), and the Ca(OH)2 dose (1.1-2.6 mmol/batch), on lab-scale thermophilic composting of anaerobic sludge. The effects on NH3 recovery, organic matter degradability, and microbial activity are evaluated. Ca(OH)2 dosing immediately improved the emission of NH3, with yields 50-69% higher than those under control conditions. The timing of the dosing did not influence NH3 recovery or organic matter degradability. Higher Ca(OH)2 doses resulted in higher NH3 recovery, while microbial activity was temporarily and marginally inhibited. The pH of the compost reached 10-11.5 but quickly dropped to 8-8.5 within a day, probably because of neutralization of Ca(OH)2 by the emitted CO2 and release of NH3, which maintained the microbial activity. The present study indicated that Ca(OH)2 dosing would be useful to apply during thermophilic composting for NH3 recovery to cultivate high-value microalgal biomass, which enables this process to obtain a more economic benefit.
This study presents a theoretical framework based on power law distribution to identify the vulnerable regions to soil loss in Susu river basin at Cameron Highlands, Malaysia by using the geomorphologic factors from Digital Elevation Model (DEM). Drainage area is used to describe the runoff aggregation structure of the watershed which represents the magnitude of discharge. Stream power is also used to describe the energy expenditure pattern of the watershed. They are fitted to power law distribution by means of the maximum likelihood to estimate the threshold for soil loss. The landscape stability condition is assessed through the mechanism of channel initiation. Two regions in the slope area plot are recognized as the regimes susceptible to soil loss, in that discharge, local slope and energy are sufficient for the initiation of soil movement. The result is further improved by incorporating the Topographic Wetness Index (TWI) aiming to locate vulnerable regions to soil loss under the dynamic saturation process. The final result indicates that the vulnerable regions expand from perennial reaches to ephemeral reaches as saturation process develops. It implies the transition of runoff generation from groundwater in perennial reaches to surface runoff in ephemeral reaches. Identification of soil loss vulnerable regions under the dynamic saturation process helps in planning of the mitigation measures for soil erosion.
This study was carried out at an ultrabasic area, Selaru (S1 & S2) dan Felda Rokan Barat (S3), Kuala Pilah, Negeri Sembilan. Eighteen samples of plant and their substrates were collected from study area. The purpose of this study was to determine heavy metal such as Ni, Cr, Mn, Co, Fe and Zn contents in soils and different parts of the plant, such as leaf, stem, root and fruit. Biologal Absorption Coefficient (BAC) of the plant was obtained by calculation. Heavy metals content in the plant were extracted by digestion method whereas in soil the heavy metals were extracted by sequential extraction. Heavy metals content in soil and plant extract was determined using Flame Atomic Absorption Spectrophotometer. It was found that heavy metal concentrations in soil substrate for mengkudu (Morinda citrifolia) were high for Fe followed by Cr, Ni, Mn, Zn and Co with average concentration of 1208.5, 583.4, 352.4, 352.4, 70.7 and 53.6 mg.kg-1, respectively. Available Mn and Zn concentrations were higher than the other heavy metals in term of percentage. Fe and Mn were dominant in all parts of plants however in terms of BAC average, Co showed the highest enrichment value in all parts of the plants.
Centella asiatica is widely used as a medicinal plant in Malaysia and other parts of the world. In the present study, the growth and uptake of heavy metal by C. asiatica were determined based on the plant exposure to different treatment of metal-contaminated soils under laboratory conditions. Heavy metals uptake in different parts of the plants namely roots, stems and leaves were determined. In general, it was found that the metal uptake capacity followed the order: roots > stems > leaves. Since a close positive relationship was established between the concentrations of metal accumulated in different parts of the plant and the metal levels in the most contaminated soil, C. asiatica has the potential of being used as a biomonitoring plant for heavy metal pollution in the polluted soils.
Infiltration caused by rainfall will lead to the changes of moisture content and soil pore water pressure or matric suction of the soil. These changes indicate the behavior of the soil especially during wetting and drying process. This paper presents the experimental test result of rain water infiltration into soil column for two samples of soils. The main objectives were to study the effect of rainfall intensity and duration of soil infiltration process for the forest soil and to compare its result to the gravelly sand. Infiltration experimental in this study involved three main components; water supply system, soil column and instrumentations, including percolation collection system. This study uses two types of tensiometers; 5 and 10 cm long. The results of TDR and tensiometers which were used to obtained moisture content and matric suction, respectively, shows that the system was successfully developed. For the forest soil, the result showed that moisture content of the top section is higher compared with the other sections. On the other hand, for gravelly sand, the moisture content in middle section is higher compared with the top and bottom section of the soil. Meanwhile, matric suction for both soils dropped during rainfall and gradually increases towards drying process. Other than that the comparison of soil matric suction between 5 and 10 cm tensiometers shows significant results for gravelly sand compared to forest soil.
Selenium (Se) has been recognized as an essential nutrient for humans. Plant foods are the predominant source of selenium and majority of dietary selenium is absorbed depending on the type of food consumed. Nowadays, green tea is becoming increasingly popular for its prominent health benefits, including the ability to supplement selenium in organically bound, natural food form. The selenium content of Se-enriched green tea is influenced by the selenium level of local soils in which it is grown. However, selenium content of plants can also be improved by artificial fortification methods. In this review, the chemical speciation and biological functions of selenium, fortification methods, biological activities and nutraceutical applications of Se-enriched green tea are discussed. This review provides insights into the current research and the importance of Se-enriched green tea in the enrichment of human nutrition and health.
A reciprocal transplant-replant experiment was carried out to investigate the clonal plasticity and local specialization of OAFE population (O type) and BF population (U type) of a clonal rhizome herb Iris japonica in contrasting reciprocal heterogeneous habitats on Jinyun Mountain. U Population had better performance of plant size and clonal propagation (including allocation to clonal propagation, daughter ramet and fine rhizome) in different reciprocal heterogeneous habitats than O population. Both the population origin and reciprocal spatial heterogeneous habitat had effects on clonal ramets and biomass of clonal components of experimental plants. The plasticity of clonal growth had difference in clonal components to balance High light-Low soil resources (water) (HL) or Low light-High soil resources (LH) due to the ecological isolation of the two I. japonica populations. Our findings indicated that two major types of patterns of spatial covariance of resources can have different effects on the growth and local variation of clonal plants.
Diplotaxis tenuifolia is a medicinally important perennial plant species, distributed widely alongside the roads in Turkey. The samples were collected from 54 sites, including highways, sideways, industrial areas, urban centres and rural environs. Both the plant and soil samples were analysed to determine the concentrations of different metals using AAS. The results showed that in the soil samples copper and lead were highest near highway 45.533 and 2.865 mg/kg, respectively; but lowest values of copper were determined around industrial areas (3.514 mg/kg), latter however showed higher concentrations of cadmium (0.726 mg/kg) and iron (82.766 mg/kg). The lead as well as iron were the lowest around sideways 1.917 mg/kg and 54.073 mg/kg, respectively, whereas chromium concentrations in the soils were highest near sideways (18.397 mg/kg) and lowest around industrial areas (0.182 mg/kg). The sideways showed very low nickel concentrations (0.271 mg/kg), as compared to the rural areas which had higher nickel concentrations (0.726 mg/kg). No cadmium was detected in the urban soil samples. In the plants copper and chromium were higher in the urban areas 50.130 and 0.238 mg/kg, respectively. The former was lowest around sideways (32.377 mg/kg) and latter around highways (0.114 mg/kg). Both nickel and cadmium were higher in the samples from industrial areas 0.238 and 0.016 mg/kg, respectively. Their values around the highways were lowest 0.182 and 0.005 mg/kg. The samples from urban sites revealed highest values of lead (3.474 mg/kg) and iron (61.304 mg/kg), but the values of lead were lowest around sideways (2.420 mg/kg) and those of iron in the vicinity of industrial areas (20.600 mg/kg). All these findings depict that there is some aerial deposition of these metals on the leaves. A significant correlation is seen between the plants and the soils.
Natural radioactivity in coastaline area soil of Ado-Odo/Ota has been carried out to ascertain the presence of radionuclides using gamma-ray spectroscopy (HPGe detector). The result showed that U-238, Th-232 and K-40 ranged from 24 ± 7-49 ± 10; 67 ± 6-120 ± 9 and 88 ± 17-139 ± 20 Bqkg-1 respectively. The radium equivalent for the samples ranged from 132.51 to 230.91 Bqkg-1 with mean value of 185.89 Bqkg-1. The mean value for the gamma dose rate for the soil samples was estimated to be 81.32 nGyh-1. The estimated values of annual effective dose equivalent ranged from 0.61 to 1.07 mSv y-1. The estimation of alpha index representative (Iα) ranged from 0.12 to 0.24 with mean value of 0.21 while the gamma representative index ranged between 0.465 and 0.810. The activity utilization index of the soil samples ranged from 1.09 to 1.89 with mean value of 1.53. The radiological implication in the study area has shown that the soil samples with gamma dose rate value of 89.99 nGyh-1, 94.39 nGyh-1, 97.40 nGyh-1 and 101.04 nGyh-1 respectively are higher than the recommended value of 80 nGyh-1 and may pose health implication for long term exposure.
The exponential growth of waste generation is posing serious environmental issues and thus requires urgent management and recycling action to achieve green sustainable development. Controlled low-strength material (CLSM) is a highly flowable cementitious backfill material with self-consolidating properties. The CLSM efficiency during construction and final performance at the site depends on its plastic properties. Plastic properties are responsible for workability, pumpability, stability, and lateral pressure on adjacent soils. This paper presents a critical review to date on the use of waste materials and/or by-products and their impacts on the plastic properties of the CLSM. Extensive previous studies demonstrated that the basic properties and content of waste materials as well as the amount of water in the mix design, play a dominant role in determining the plastic properties of CLSM. The discussed plastic properties of CLSM include flowability, bleeding, segregation, and hardening time, which are found to be inter-related. Proper mix design adjustment to accommodate the use of waste materials is possible to produce sustainable CLSM with acceptable plastic properties. Additionally, the discussion and analysis presented in this paper could provide a basis for future research advances and the development of sustainable CLSM prepared with waste materials.
The suction between soil particles is the basis and core problem in the study of unsaturated soil. However, is the suction between soil particles just the matrix suction (which has been widely used since the discipline of unsaturated soil mechanics was established). In fact, the concept of matrix suction is from soil science and reflects the water-absorbing capacity of the soil. Matrix suction characterizes the interaction between soil particles and pore water rather than the interactions between soil particles, which were not in conformity with the principle of effective stress of soils. The suction of unsaturated soil, in essence, is the intergranular suction composed of absorbed suction and structural suction. In this paper, first, the basic concepts of absorbed suction and structural suction were briefly introduced. Then, with soil mechanics, powder science, crystal chemistry, granular material mechanics and other related disciplines of knowledge for reference, the quantitative calculation formulas were theoretically deduced for the absorbed suction for equal-sized and unequal-sized unsaturated soil particles with arbitrary packing and the variable structural suction for equal-sized unsaturated soil particles with arbitrary packing and unequal-sized unsaturated soil particles with close tetrahedral packing. The factors that influence these equations were discussed. Then, the shear strength theory of unsaturated soil was established based on the theory of intergranular suction through the analysis of the effective stress principle of unsaturated soil. This study demonstrates that the shear strength of unsaturated soil consists of three parts: The effective cohesive force, the additional strength caused by external loads and the strength caused by intergranular suction. The contribution of the three parts to the shear strength of unsaturated soil depends on the following influence factors: Soil type, confining pressure, water content and density. Therefore, these factors must be comprehensively considered when determining the strength of an unsaturated soil.
The serious deterioration of the ecological environment comes from a large number of geological disasters. These disasters were caused by a number of engineering activities. Ecological restoration is an important measure to reduce geological disasters and protect the ecological environment. On the basis of the introduction of cast-in-situ grids technology, external-soil spray seeding technology and vegetation bag technology, according to the ecological restoration experiment of the road slope attach to the Three Gorges Pumped-Storage Power Station in Hohhot, decision analysis of slope ecological restoration is done with AHP. It is shown that in arid and semi-arid area, selection of slope ecological restoration scheme mainly needs considering the ecological effect and stability. The major factor of ecological effects is survival rate of vegetation. The major factor of stability is the stability in a whole. Cast-in-situ grids technology will be the first choice for ecological restoration of road slope in arid and semi-arid area. This study provides reference for decision of the slope ecological restoration in arid and semi-arid region.
The soil temperature near four external walls with different orientations was investigated in spring and summer. In both
seasons, the soil temperature was higher in the positions closest to the buildings, suggesting that the buildings were a
heat source for the soil surrounding them. Therefore, it could be confirmed that there was lateral heat transfer between
the soil and the buildings. Based on this, a soil heat flux plate was set between the soil and the buildings to investigate the
horizontal heat flux. The data showed diurnal variations of the horizontal heat flux in both spring and summer. In order
to determine the factors that influenced the horizontal heat flux and to provide a basis to understand its mechanism, the
correlations between the data of several meteorological factors and the horizontal heat flux were analysed. The results
showed that solar radiation was significantly correlated with the horizontal heat flux (p<0.0001) in any single season and
in the two seasons that were studied. Additionally, other meteorological factors (net radiation, air temperature, relative
humidity and soil temperature and moisture) showed strong correlations with the horizontal heat flux on a diurnal scale
only. On a seasonal time scale, the correlation might be significant (p<0.0001) as well, but the correlation coefficients
decreased too significantly, such as those for soil temperature, air temperature and relative humidity. Alternatively, the
correlation might not be significant (p>0.05), such as that for soil moisture. The stepwise regression results indicated
that the relative importance of these meteorological factors was 48.63, 21.94, 14.44, 8.12 and 6.87% for solar radiation,
soil temperature, air temperature, relative humidity and soil moisture, respectively, on a diurnal scale.
Termites are found in various habitats, particularly diverse communities occurring in tropical forest and peatlands.
Termites are beneficial insects, which function as soil engineers, improving the soil quality. However, in peatlands
converted to commercial oil palm plantations, they are considered as pests. There is lack of studies on termite communities
in converted peatlands in Peninsular Malaysia. Thus, this study investigated termite species associated with oil palm
stands in three soil types (clay, shallow peat and deep peat) in Endau Rompin Plantation. The stand scouting method
was used to record the numbers and types of termites associated with palm trees in the individual stands on different
soil types. A total of 29 termite species associated with the palm stands were identified morphologically. All the species
belonged to the families Rhinotermitidae and Termitidae. Twenty-three of the 29 species were found in the shallow peat,
16 in clay soil and 15 in deep peat. The community structure was synthesized by two-way cluster analysis with Sorensen
(Bray Curtis) distance measure. Five termite groups associated with two soil types (clay soil and shallow/deep peat)
were generated. Moisture levels and organic content were likely to determine the presence of soil feeders identified in
the presence study. This study provides information on the status of termite species in oil palm plantation areas. Such
information may be useful in future planning strategies by the plantation management.
Oil palm (Elaeis guineensis) agriculture is rapidly expanding and requires large areas of land in the tropics to meet the global demand for palm oil products. Land cover conversion of peat swamp forest to oil palm (large- and small-scale oil palm production) is likely to have negative impacts on microhabitat conditions. This study assessed the impact of peat swamp forest conversion to oil palm plantation on microclimate conditions and soil characteristics. The measurement of microclimate (air temperature, wind speed, light intensity and relative humidity) and soil characteristics (soil surface temperature, soil pH, soil moisture, and ground cover vegetation temperature) were compared at a peat swamp forest, smallholdings and a large-scale plantation. Results showed that the peat swamp forest was 1.5-2.3 °C cooler with significantly greater relative humidity, lower light intensities and wind speed compared to the smallholdings and large-scale plantations. Soil characteristics were also significantly different between the peat swamp forest and both types of oil palm plantations with lower soil pH, soil and ground cover vegetation surface temperatures and greater soil moisture in the peat swamp forest. These results suggest that peat swamp forests have greater ecosystem benefits compared to oil palm plantations with smallholdings agricultural approach as a promising management practice to improve microhabitat conditions. Our findings also justify the conservation of remaining peat swamp forest as it provides a refuge from harsh microclimatic conditions that characterize large plantations and smallholdings.