This paper reports a computational approach for analysis of FTIR spectra where peaks are detected, assigned and matched across samples to produce a peak table with rows corresponding to samples and columns to variables. The algorithm is applied on a dataset of 103 spectra of a broad range of edible oils for exploratory analysis and variable selection using Self Organising Maps (SOMs) and t-statistics, respectively. Analysis on the resultant peak table allows the underlying patterns and the discriminatory variables to be revealed. The algorithm is user-friendly; it involves a minimal number of tunable parameters and would be useful for analysis of a large and complicated FTIR dataset.
A computer-aided multivariate water quality index is developed based on partial least squares (PLS) regression. The index is termed as the partial least squares water quality index (PLS-WQI). Briefly, a training set was computationally generated based on the guideline of National Water Quality Standards for Malaysia (NWQS) to predict the water quality. The index is benchmarked with the well-established index developed by the Department of Environment, Malaysia (DOE-WQI). The PLS-WQI is a continuous variable with the value closer to I indicating good water quality and closer to V indicating poor water quality. Unlike other conventional indexing methods, the algorithm calculates the index in a multivariate manner. The algorithm allows rapid processing of a large dataset without tedious calculation; it can be an efficient tool for spatial and temporal routine monitoring of water quality. Although the algorithm is designed based on the guideline of NWQS, it can be easily adapted to accommodate other guidelines. The algorithm was evaluated and demonstrated on the simulated and real datasets. Results indicate that the algorithm is robust and reliable. Based on six parameters, the overall ratings derived are inversely correlated to DOE-WQI. When the number of parameter is increased, the overall ratings appear to provide better insights into the water quality.
Fourier Transform Infrared (FTIR) and Gas Chromatography Mass Spectrometry (GCMS) are two common instruments used for analysis of edible oils. The output signal is often analysed on the software attached to the workstations. The processing software is usually individualised for a specific source. The output of GCMS cannot be analysed on the FTIR hence analysts often need to juggle between instruments when multiple techniques are employed. This could become exhaustive when a large dataset is involved. This paper reports a synchronised approach for analysis of signal from FTIR and GCMS. The algorithm is demonstrated on a dataset of edible oils to investigate the thermal degradation of seven types of edible oils treated at 100°C and 150°C. The synchronised routines identify peaks present in FTIR and GCMS spectra/chromatograms where the information is subsequently extracted onto peak tables for further analysis. In this study, it is found that palm based products and corn oils were relatively more stable with higher content of antioxidants tocopherols and squalene. As a conclusion, this approach allows simultaneous analysis of signal from multiple sources and samples enhancing the efficiency of the signal processing process.
In this study, various HCl-supported hydrochar made from root powder of long-root Eichhornia crassipes were applied to adsorb aqueous sulfachloropyridazine (SCP). Adsorption capacity (qe μg g-1) was positively correlated with combined severity-CS. With CS increasing, carbonization degree, hydrophobicity, porosity and isoelectric point of hydrochar increased, but content of polar functional groups decreased. Hydrophobic interaction was important for SCP adsorption. A 24 × 36 peak area table was generated from 24 FT-IR absorbance spectra computed by peak detection algorithm. Afterwards, correlation analysis between qe μg g-1 and FT-IR peak area were conducted, indicating that wavenumbers at 555.4, 1227.47, 1374.51, 1604.5, 2901.4/2919.2 and 3514.63 cm-1 were helpful for SCP adsorption. Further, multivariate linear regression analyses showed that aromatic skeleton and phenolic hydroxyl were the two biggest contributors. Electrostatic attraction did not exist during the SCP adsorption process. Under strong acid condition, protonated amino groups in cationic SCP acting as a hydrogen donator interacted with electron-rich functional groups onto hydrochar by Hydrogen interaction. Under weak acid condition, neutral SCP served as an π electron donor to bond with hydrochar by π-π electron donator-acceptor interaction. This work could guide the functional groups modification strategy of hydrochar to make better use of it in water purification field.
Quantitative indices are classically employed to evaluate the contamination status of metals with reference to the baseline concentrations. The baselines vary considerably across different geographical zones. It is imperative to determine the local geochemical baseline to evaluate the contamination status. No study has been done to establish the background concentrations in tropical rivers of this region. This paper reports the background concentrations of metals in water and sediment of the Baleh River, Sarawak, derived based on the statistical methods where the areas possibly disturbed are distinguished from the undisturbed area. The baseline levels of six elements in water determined were Al (0.34 mg/L), Fe (0.51 mg/L), Mn (0.12 mg/L), Cu (0.01 mg/L), Pb (0.03 mg/L), and Zn (0.05 mg/L). Arsenic and selenium were below the detection limit. For sediment, the background values were established according to statistical methods including (mean + 2σ), iterative 2σ, cumulative distribution frequency, interquartile, and calculation distribution function. The background values derived using the iterative 2σ algorithm and calculated distribution function were relatively lower. The baseline levels calculated were within the range reported in the literatures mainly from tropical and sub-tropical regions. The upper limits proposed for nine elements in sediment were Al (100,879 mg/kg), Cr (75.45 mg/kg), Cu (34.59 mg/kg), Fe (37,823 mg/kg), Mn (793 mg/kg), Ni (22.88 mg/kg), Pb (27.26 mg/kg), Zn (70.64 mg/kg), and Hg (0.33 mg/kg). Quantitative indices calculated suggest low risk of contamination at the Baleh River.
Metallic contamination in seafood, especially fish, has been of increasing concern to human health. Moreover, with increasing dependency on farmed fish for fish resources, the metallic contamination in them is still questionable. This study aimed to investigate the effects of cooking (steaming) on heavy metal concentration in farmed fish and to estimate its potential human health risk. Farmed sea basses (Lates calcarifer) from Setiu Lagoon were used to study the difference in metal uptake through human consumption of raw and cooked (steamed) fish samples. Selected heavy metals, namely copper (Cu), zinc (Zn), arsenic (As), cadmium (Cd), mercury (Hg) and lead (Pb), were measured using ICP-MS following Teflon bomb closed digestion of the fish samples. Cooking of the fish muscle by steaming was applied to investigate if cooking changes the concentration of heavy metals. Mercury and As were found accumulated more notably in the fish muscle, though only Hg was found to show significant (p > 0.05) increase when L. calcarifer is cooked. The amount of As in the fish muscle throughout its growth can be potentially harmful to humans, with the highest averaged concentration at 3.29 ± 0.65 mg/kg dw. above the standard set by the Malaysian Food Regulation (1985) of >1 mg/kg. All the other heavy metals were at relatively safe concentrations well below the standard set by both national and international guidelines. The PTWI per individual of L. calcarifer for As was at 0.84 mg/kg bw., which indicated that the amount of this fish safe for consumption without any adverse effect is 170 g/week. Therefore, long-term intake of these fish may pose a risk to human health due to the relatively higher Hg and As concentration found in these fishes.
Assessment of river water quality is essential as it provides the knowledge required to make informed decisions. Therefore, water quality was determined at 15 tributary stations located along the Batang Baleh, Sarawak. Results of the study indicate that all tributaries were well-aerated (≈ 7.7 mg/L) with pH (≈ 7.3) and conductivity (≈ 37.3 μS/cm) values falling within acceptable ranges. However, there were tributaries that showed very high turbidity (> 1000 NTU) and suspended solids (> 800 mg/L) which were contributed by the soil erosion from logging activities in the watershed. Tributary stations associated with logging activities also showed significantly higher total phosphorus and organic nitrogen. Cluster analysis demonstrated that water quality at tributary stations along the Batang Baleh exhibited a longitudinal variation from upstream to downstream regions, particularly, dissolved oxygen, five-day biochemical oxygen demand, and nitrite-nitrate nitrogen, which were found higher in upstream region and steadily decreased towards the downstream region. Two stations located at Sg. Serani and Sg. Melatai were distinct from the other stations with the highest concentrations of turbidity, total suspended solids, organic nitrogen, and total phosphorus. Thus, there is an urgent need to reduce the pollutants in the tributaries of Batang Baleh for the health of the sensitive aquatic organisms.
Knowledge of the fundamental aspects of ecology such as the patterns of fish species distribution and biodiversity in the forest streams is the first and basic step to develop effective conservation strategies. Yet, studies on altitudinal changes of fish composition and assemblages in Bornean forest streams are scarce despite being one of the hotspots of biodiversity conservation. Hence, surveys on freshwater fish composition along the altitudinal gradients of the Baleh River Basin in Sarawak, Borneo were conducted from April 2014 to August 2015. The Baleh River Basin was divided into seven altitudinal groups with a total of 72 stations. Group elevation ranged from 53 to 269 m above sea level. The fish samples and environmental parameters were taken concurrently during samplings. A total of 3565 specimens belonging to six orders, 14 families, and 76 species were found in the present study. The most dominant family in the Baleh River Basin was Cyprinidae (74.4%), followed by Gastromyzontidae (16.2%) while the most dominant species was Tor tambra (12.9%), followed by Lobocheilos ovalis (12.3%). Fish abundance significantly higher at high altitude sites than those at low altitude sites except for Mengiong River which has the lowest fish abundance despite with high elevation. Species richness was found significantly lower in midstream segment. Noticeable altitudinal gradient of fish assemblages was observed along the Baleh River except a discontinuity at the midstream segment which is attributable to the poorer quality inflow from the Mengiong River coupled with the meandering feature of the segment. Fish abundance was significantly and positively correlated with elevation, water pH and conductivity while negatively correlated with turbidity. Anthropogenic activities in the Baleh River Basin had altered the environmental variables thus disrupted the altitudinal gradient of fish assemblages. This phenomenon is apparent when the Canonical Correspondence Analysis (CCA) revealed that the first axis (CCA1) explained 42.5% of the variation and has positive loading on dissolved oxygen (DO) and negative loading on water conductivity; whereas CCA2 explained 37.5% of the variation and positively loaded on elevation, water pH, and DO. The results demonstrated that Gastromyzon fasciatus preferred more oxygenated water than Protomyzon sp., G. sp 1, and G. punctulatus although they are all from Gastromyzontidae family that inhabiting high altitude sites. Barbonymus schwanenfeldii was also found most abundant with elevated dissolved oxygen value. On the other hand, Rasbora volzii and R. hosii inhabiting lower altitude sites with less oxygenated and more acidic water.
Shorea macrophylla belongs to the Shorea genus under the Dipterocarpaceae family. It is a woody tree that grows in the rainforest in Southeast Asia. The complete chloroplast (cp) genome sequence of S. macrophylla is reported here. The genomic size of S. macrophylla is 150,778 bp and it possesses a circular structure with conserved constitute regions of large single copy (LSC, 83,681 bp) and small single copy (SSC, 19,813 bp) regions, as well as a pair of inverted repeats with a length of 23,642 bp. It has 112 unique genes, including 78 protein-coding genes, 30 tRNA genes, and four rRNA genes. The genome exhibits a similar GC content, gene order, structure, and codon usage when compared to previously reported chloroplast genomes from other plant species. The chloroplast genome of S. macrophylla contained 262 SSRs, the most prevalent of which was A/T, followed by AAT/ATT. Furthermore, the sequences contain 43 long repeat sequences, practically most of them are forward or palindrome type long repeats. The genome structure of S. macrophylla was compared to the genomic structures of closely related species from the same family, and eight mutational hotspots were discovered. The phylogenetic analysis demonstrated a close relationship between Shorea and Parashorea species, indicating that Shorea is not monophyletic. The complete chloroplast genome sequence analysis of S. macrophylla reported in this paper will contribute to further studies in molecular identification, genetic diversity, and phylogenetic research.