Tinjauan awal potensi ketidakstabilan cerun dan cirian fiziko-kimia tanah di Cameron Highlands, Pahang : Preliminary survey on potential slope instability and soil physico-chemical characteristic in Cameron Highlands, Pahang

Geologically Cameron Highlands was formed by a granite batholith intruding into the older sedimentary rocks. Intrusion of this acidic igneous rock formed metasedimentary rocks and other metamorphic rocks as roof pendants. The schist had been highly weathered, coloured bright grey to dark grey having fine to medium size grains with an obvious foliation. Meanwhile the granitic rock is composed of quartz, feldspar and biotite and/or tourmaline grains. Most of the road slopes cut across the granite body and slope instability survey was carried out based on type of failure, geometry and physico-chemical properties of soil slopes. Field observations showed that most of the failed slopes were soil slopes, and the slip that occurred were either shallow slip or deep slide types. Among the factors that influenced slope instability were slope geometry such as slope height and steep slope gradient, friable features of the weathering profile and the lack of surface vegetation cover. This rendered the slope surface exposed to the direct raindrop impact. Surface water run-off has also caused the development of erosion gullies on soil slope surface. Physico-chemical properties of slope material such as particle size distribution, pH, organic matter content, iron oxide content, water content, true and bulk density, and porosity were also influential in slope stability of the slopes investigated. Low soil pH (acidic) of all the slopes examined decreased iron oxide content of soil which acted as a cementing agent to soil aggregates. This has caused the soil aggregate to become weaker and easier eroded

Effect of COVID-19 movement control order policy on water quality changes in Sungai Langat, Selangor, Malaysia within distinct land use areas

For the first time in the 21st century, many nations have been forced to conduct a lockdown that restricts their industrial, transportation, and social activities to avoid the extensive COVID-19 spread. Therefore, our study aimed to analyze the status of water quality that was measured by suspended particulate matter (SPM) in Sungai Langat, Selangor, Malaysia using the remote sensing technique. The study was concerned with rivers located in distinct land-use areas such as high-density urban, low-density urban, and agricultural areas. The study period included before and after movement control order (MCO) periods that occurred in February 2020 and February 2021, respectively. The SPM levels in each period were calculated using the remote sensing technique through Landsat-8 OLI images then they were analyzed using statistical analysis. The results of the remote sensing technique showed the highest decrease of SPM levels during the MCO period was observed in Sungai Langat within a high-density urban area (34.1%). Then, the SPM levels in all Sungai Langat raised significantly after the MCO period with the highest change at 31.6%. Rainfall and erosion factors had a significant impact on the SPM level through natural processes but the COVID-19 restriction had a direct impact on the SPM level due to the restriction of industrial and social activities. The suspended activities have made the lower emission compared with before the COVID-19 period in 2019

Effect of cement additive and curing period on some engineering properties of treated peat soil

Peat soil is characterized by its high content of decomposed organic matter. Majority of areas occupied by peatland have been developed for agriculture sectors such as pineapple cultivation and oil palm. Due to its geotechnical drawback characteristics such as highly compressibility and low shear strength, peat soil is classified as problematic soils and unstable for engineering structures. Lack of suitable and expensive price of lands, peatland will be an alternative option for future development. Prior to construction works, stabilization of peat soil should be performed to enhance its engineering characteristics. This paper presents the effect of cement and curing period on engineering properties of the cement-treated peat soil. Some engineering variables were examined including the compaction behaviour, permeability and unconfined compressive strength (UCS). The Atterberg limit test was also carried out to examine the influence of cement addition on peat soil. The cement-treated peat soils were prepared by adding varying amount of ordinary Portland cement (OPC) ranging between 0% and 40% of dry weight of peat soil. In order to examine the effect of curing, the treated samples were dried at room temperature for three and seven days while for UCS tests samples were extended to 28 days prior to testings. The results showed that the liquid limit of treated soil decreased with the increase of cement content. Maximum dry density (MDD) increased while optimum moisture content (OMC) dropped with the increase in cement content. Permeability of treated soil decreased from 6.2×10-4 to 2.4×10-4 ms-1 as cement content increase from 0% to 40%. In contrast, the UCS tests indicated an increase in uncompressive strength with the increase in cement contents and curing period. The liquid limit and permeability were also altered as curing periods were extended from three to seven days. This study concluded that geotechnical properties of peat soil can be stabilized using ordinary cement and by modification of the curing periods

Effect of COVID-19 Movement Control Order Policy on water quality changes in Sungai Langat, Selangor, Malaysia within distinct land use areas

For the first time in the 21st century, many nations have been forced to conduct a lockdown that restricts their industrial, transportation, and social activities to avoid the extensive COVID-19 spread. Therefore, our study aimed to analyze the status of water quality that was measured by suspended particulate matter (SPM) in Sungai Langat, Selangor, Malaysia using the remote sensing technique. The study was concerned with rivers located in distinct land-use areas such as high-density urban, low-density urban, and agricultural areas. The study period included before and after movement control order (MCO) periods that occurred in February 2020 and February 2021, respectively. The SPM levels in each period were calculated using the remote sensing technique through Landsat-8 OLI images then they were analyzed using statistical analysis. The results of the remote sensing technique showed the highest decrease of SPM levels during the MCO period was observed in Sungai Langat within a high-density urban area (34.1%). Then, the SPM levels in all Sungai Langat raised significantly after the MCO period with the highest change at 31.6%. Rainfall and erosion factors had a significant impact on the SPM level through natural processes but the COVID-19 restriction had a direct impact on the SPM level due to the restriction of industrial and social activities. The suspended activities have made the lower emission compared with before the COVID-19 period in 2019

Flood analysis of December 2006: focus at Segamat Town, Johor

This study aimed to ascertain the causes of Segamat flood which occurred from 17 to 21 December 2006. Actvities include collection, evaluation and analysis of rainfall data from January 1998 to December 2006, and analysis of daily telemetry for water levels and discharge in December 2006. The daily, monthly and annual rainfall of Felda Medoi Station, Segamat were analyzed and correlated with the telemetry data. Based on the 9 years rainfall data, monthly rainfall in Segamat area ranged from 2.5 mm (Februari 2004) to 536.8 mm (January 2003). Monthly rainfall distribution from October to December 2006 increased from 118 mm to 435 mm but decreased (392 mm) in January 2007. Our result showed that extra ordinary heavy downpour, low and undulating topography of the study area was identified as the main cause for the Segamat flood. Keywords: 2006 Segamat flood; Felda Medoi station; stream flow; telemetry dat

Penentuan kepekatan radionuklid tabii dan indeks bahaya radiologi akibat penggunaan Condisoil® ke atas penanaman Hibiscus cannabinus (Kenaf)

Kajian ini bertujuan menentukan kepekatan aktiviti radionuklid tabii (226Ra, 228Ra dan 40K) dalam tanah, air dan tumbuhan serta faktor pemindahan daripada tanah kepada tumbuhan dan indeks bahaya radiologi akibat penggunaan Condisoil®. Sebanyak 4 sampel tanah, 14 sampel air dan 4 sampel tumbuhan telah dianalisis menggunakan sistem spektometri sinar gama. Keputusan kajian mendapati julat kepekatan aktiviti 226Ra, 228Ra dan 40K dalam sampel tanah yang menggunakan Condsoil® masing-masing adalah 13.8 - 17.6, 15.7 - 21.0 dan 44.5 - 57.7 Bq kg-1. Julat kepekatan aktiviti 226Ra, 228Ra dan 40K dalam sampel tumbuhan pula masing-masing adalah 5.0 - 18.5, 0.1 - 1.5 dan 42.7 - 321.8 Bq kg-1. Bagi sampel air, julat kepekatan aktiviti bagi radionuklid 226Ra, 228Ra dan 40K masing - masing adalah 0.3 - 0.9, 0.3 - 3.9 dan 1.4 - 11.6 Bq L-1. Julat faktor pemindahan radionuklid 226Ra, 228Ra dan 40K daripada tanah ke tumbuhan masing-masing adalah 0.42 - 0.71, 0.01 - 0.08 dan 0.85 - 5.34. Penilaian bahaya radiologi mendapati indeks kesetaraan radium berada di bawah nilai had yang dicadangkan iaitu 370 Bq kg-1. Sehubungan dengan itu, kajian ini mendapati penggunaan Condisoil® sebagai bahan penambahbaikan tanah tidak menyebabkan pertambahan radionuklid tabii ke dalam alam sekitar serta tidak mendatangkan risiko bahaya radiologi kepada manusia

Effects of Single and Consortia Inoculants on the Biodegradation Efficiency of Crude Oil in Seawater

A bioremediation study was undertaken to assess the biodegradation efficiency of crude oil in seawater using two locally isolated strains namely Candida tropicalis RETL-Cr1 and Pseudomonas aeruginosa BAS-Cr1. The inoculation was carried out using single strains labelled as T1; Candida tropicalis RETL-Cr1, T2; single strain Pseudomonas aeruginosa BAS-Cr1 and T3; mixture of both cultures respectively. The biodegradation capability of each strain was examined in a shakeflask culture at 30˚C, agitated at 200 rpm for 28 days. The growth profile was monitored by measuring the optical density (OD600) using spectrophotometry. The biodegradation efficiency of crude oil was quantified by comparing the initial and final crude oil concentrations, whereas the degradation of selected aliphatic hydrocarbons was quantified using gas chromatography-mass spectrometry (GC-MS) by comparing the initial and final area in chromatograms. The present finding showed that in 5% (v/v) of crude oil, consortia cultures had the highest degradation, with 50%, while single cultures of C. tropicalis RETL-Cr1 and P. aeruginosa BAS-Cr1 achieved 39% and 27%, respectively. The results of biodegradation showed that consortia cultures experienced 1.3- fold higher compared to a single culture of C. tropicalis RETL-Cr1 and 2-fold higher compared to a single culture of P. aeruginosa BAS-Cr1. Based on GC-MS analysis, the aliphatic hydrocarbons were found degraded through the treatment with the highest degradation recorded in consortia cultures: octadecane (73.93%) > eicosane (73.23%) > nonadecane (70.43) > docosane (67.64%) > heptadecane (66.36%) > heneicosane (65.94%) > tricosane (62.28%). From the results obtained, it can be concluded that the potency of microbes as excellent hydrocarbon degraders is as follows: consortia (mixed of two species) > C. tropicalis RETL-Cr1> P. aeruginosa BAS-Cr1. This supports the idea that microbial communities, especially in mixtures, have the ability to degrade hydrocarbon contaminants more effectively and can be environmentally friendly due to their specific ability to metabolize hydrocarbons

The potential of pistia stratiotes in the phytoremediation of selected heavy metals from simulated wastewater

The pollution of heavy metals in aquatic environments is a major concern for human beings. The present study demonstrates the phytoremediation potential of the aquatic macrophyte Pistia stratiotes for removal of Cr, Pb and Ni from simulated wastewater. Pistia stratiotes was grown in Faculty of Science & Natural Resources (FSNR) lake water and spiked with different concentrations of heavy metals at 1 mg/L, 2 mg/L and 3 mg/L of Cr, Pb and Ni, respectively. The experiment was conducted within a 14-day period in laboratory conditions. The study investigated the percentage of removal of heavy metals by P. stratiotes as well as determining the distribution of heavy metal patterns in plant tissues, the bioconcentration factor (BCF), translocation factor (TF) and relative treatment efficiency index (RTEI). The results showed that P. stratiotes is efficient in removing single Pb at 1 mg/L and 3 mg/L and single Cr at 1 mg/L, with a removal efficiency of 99.31%, 79.86% and 76.25%, respectively. It was found that P. stratiotes managed to concentrate Pb in its roots up to 15,000 mg/kg in plant tissue. Data on bioconcentration factor (BCF) showed that P. stratiotes managed to reach BCF values over 6,000 each for single chromium at 2 mg/L and lead at both 2 mg/L and 3 mg/L. It was found that the plant can consistently translocate nickel from the roots to the shoots, while chromium and lead tend to concentrate in the root tissues. The results revealed that P. stratiotes uses rhizofiltration as its phytoremediation uptake mechanism. This study helps significantly to increase knowledge regarding the potential of P. stratiotes in the phytoremediation of heavy metal-polluted wastewater

Trace Elements Uptake in Brassica rapa chinensis Cultivated in Ultrabasic (Oxisol) and Ultisol Soils, North Borneo

The study aims to investigate the soil physico-chemical properties and trace elements uptake of Brassica rapa chinensis plants cultivated in ultrabasic (oxisol) and ultisoil soil of Ranau, North Borneo, Malaysia by inductively coupled plasma-optical emission spectrometry (ICP-OES). This study can contribute to propose a more sustainable soil management practice. All selected trace elements bioavailability in ultrabasic soil was significantly higher than ultisols except for Ca and Cd. There was no significant amount of difference in soil pH (slightly acidic) and electrical conductivity (slightly saline) between these soil types. However, a significant amount of difference between the percentage of soil moisture and organic matter between ultrabasic and ultisol soils was observed. These might contribute to the uptake of elements into the studied plant. The B. rapa chinensis is a hyperaccumulator of Cd and Pb for both type of soils. The B. rapa chinensis is an accumulator of As when grown in ultrabasic soil, while an accumulator of Co when grown in ultisol soil. Although Pb was not detected in ultisol soil as compared to ultrabasic soil, the concentration of Pb in plants cultivated in ultisol soil had exceeded the maximum permissible limit of Malaysia Food Regulation 1985. Soil amendment in frequently use agriculture sites needs to be conducted such as the addition of organic matter to reduce transfers of trace elements from soil to plants that can pose toxicity risk