21 research outputs found
Development of water quality index of ex-mining ponds in Malaysia / Isa Baba Koki
No full textAssessment of the water quality of ex-mining ponds for its proper utilization is pertinent considering the metal pollutants, and lack of proper environmental measures associated with the mining operations. Water samples from selected lakes in the Central Region of Peninsular Malaysia (Selangor and Negeri Sembilan) and Malacca from the Southern part were analysed in-situ for pH, DO, SS, EC, BOD, AN, and TDS; while metal elements including As, Cd, Pb, Mn, Fe, Na, Mg, and Ca were analysed off-site using inductively coupled plasma mass spectrometry and verified via certified reference materials. The variations in these water quality parameters were explored with chemometric techniques. The results from the principal component analysis, factor analysis and hierarchical cluster analysis suggested that in addition to the degree of contamination, the variations in heavy metal concentrations were mainly attributed to the ex-mining activities, whereas deviations in BOD, TDS, AN, and EC were subjected to the current domestic inputs. The linear discriminant analysis showed that water samples from the ex-mining ponds were highly associated with the concentrations of Mn, Cd, Ca and As; the model constructed with the training set gave a precise prediction with R2 = 1.000, with no misclassification shown with the validation set. In Klang Valley, ex-mining ponds generally show low pH compared to the other lakes; the As and Cd levels recorded in most of the ex-mining ponds surpassed the limits of the Malaysian Water Quality Standard which make them unfit for domestic uses. A study of man-made lakes in Melaka and Negeri Sembilan revealed basic pH and low metal concentrations (below the reference values) in which As, Mn, and Mg were associated with ex-mining ponds while pH and Na were associated with other lakes. In this case, the high positive loadings of pH, DO, Ca, and TDS on principal component 1 suggests the absence of significant anthropogenic input. Overall, the differences in geology and domestic inputs into the ex-mining ponds significantly affect the water quality and results in variation in the levels of metals and physical-chemical parameters. The associated health risk via ingestion and dermal contacts were also modelled using Monte Carlo simulation and the estimated carcinogenic and non-carcinogenic risks for both adult and children were compared with their benchmarks. Water quality index was then formulated based on the Malaysian Water Quality Standard and results from chemometric analyses were applied in the parameter selection so as to minimize subjectivity; consequently, As, Cd, Pb, pH, DO, BOD and AN were chosen. The index was applied for the evaluation of water quality of the above mentioned lakes where most of the ex-mining ponds in Klang Valley were classified as very polluted, while those in Melaka and Negeri Sembilan were rated as excellent
Determination of multi - pesticide residues in coconut water by QuEChERS - dSPE ionic liquid - based DLLME couple with high performance Liquid Chromatography - Tandem Mass Spectrometry (LCMS/MS)
No full textThe use of pesticides in agricultural practices is very vital but continuously accumulates in water, moist soil and contaminate fruits and vegetables. This eventually leads to many health issues such as congenital diseases and different forms of cancers. For this reason, the validated (SANTE 11831-2017) method of quick, easy, cheap, effective, rugged and safe (QuEChERS) with the dispersive solid phase extraction (SPE) coupled with ionic liquid-based (IL-based) in dispersive liquid-liquid microextraction (DLLME) was used for sample preparation of coconut water to determine multiple pesticides (Dursban, Diazinon, Thiamethoxam, Metalaxyl, Thiobencarb, Baycarb, Carbaryl and Propamocarb) residue using high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) instrument. The results of accuracy for relative recoveries (84 - 134%) were satisfactory because 87.5% of results were within the recommended range (70 - 120%). The precision results range (0-19%) of relative standard deviation (RSD) were also satisfactory as recommended (≤ 20%). The resulted limit of detection (LOD) and quantitation (LOQ) was satisfactorily ranged 0.08-0.92 and 0.28-3.08μg/kg respectively. The linearity range results (5 – 500 μg/kg) were evaluated (linear) with regression coefficient (R2) > 0.97. The matrix effects range (≤ -72%) were very weak. The measurement uncertainties range (7 - 27%) estimated were satisfactory as recommended (≤ 50%). Conclusively, the research indicates the reliability of the sample preparation method for multiple pesticides analysis in coconut water. Also, the concentration level for each of the pesticide analysed was found lower than the European Union maximum residue limits, which presumes that the analysed sample is safe for consumption to avoid health-related issues.Keywords: Dispersive, Liquid-Liquid Microextraction, Solid-Phase Extraction, HPLC-MS, Pesticides, QuEChER
Children and the experience of violence: contrasting cultures of punishment in northern Nigeria
No full textArising out of debates over ‘children at risk’ and the ‘rights of the child’, the article compares two contrasting childhoods within a single large society—the Hausa‐speaking peoples of northern Nigeria. One segment of this society—the non‐Muslim Maguzawa—refuse to allow their children to be beaten; the other segment, the Muslim Hausa, tolerate corporal punishment both at home and especially in Qur'anic schools. Why the difference? Economic as well as political reasons are offered as reasons for the rejection of corporal punishment while it is argued that, in the eyes of Muslim society in the cities, the threat of punishment is essential for both educating and ‘civilising’ the young by imposing the necessary degree of discipline and self‐control that are considered the hallmark of a good Muslim. In short, ‘cultures of punishment’ arise out of specific historical conditions, with wide variations in the degree and frequency with which children actually suffer punishment, and at whose hands. Finally the question is raised whether the violence experienced in schooling has sanctioned in the community at large a greater tolerance of violence‐as‐‘punishment’
Global Stability Analysis of Oseltamivir–resistant Influenza Virus Model
No full textAbstractWe study a new model describing the dynamics of both Oseltamivir resistant and non- resistant Influenza virus. Incorporated in the model is oseltamivir drug for the non- resistant strain and nalidixic acid or dorzolomide drugs for the resistant strain. The basic reproduction ratios R0 are determined using the next generation matrix. The local and global asymptotic stability of the disease free equilibrium are determined and shown to only exist if R01≤1 and R02≤1. Local and global asymptotic stability of the endemic equilibria exist if R01>1 and R02>1. Lyapunov function was used to show the global stabilities
Dissolved Sediment Delivery by the Samaru Stream into Kubanni Reservoir of Ahmadu Bello University Zaria, Nigeria
No full textThis study analyzes the dissolved sediment delivery by Samaru stream, a tributary of Kubanni reservoir. The stream was monitored for 7 months, from 1st of April to 10th of October, 2014 which mainly marks the flow period of the year. The study analyzed the dissolved sediment concentration (DSC), discharge (Q), relationship between dissolved sediment discharge (DSD) and discharge (Q) and the estimate of the dissolved sediment yield for the year. The velocity and cross sectional area (AV) method was employed for the discharge measurement of the stream which gave a mean value of 0.2528 m3/s, and an annual total discharge value of 4,850,232 m3/yr. The lowest discharge of 0.057 m3/s was recorded in April and the highest discharge of 4.133 m3/s was recorded in August. DSC obtained varies from a minimum value of 20 mg/L to a maximum value of 120 mg/L with a mean value of 58.87 mg/L, and total sum of 4180 mg/L. DSD using the rating curve varied from a minimum value of 1.14 mg/s to a maximum value of 325.44 mg/s, and a total value of 3162 mg/s. DSD and Q were related and it gave a strong relationship because both values of r (0.866) and r2 (0.749) are high. A total value of 174,000 kg/yr was estimated as the dissolved sediment yield of the stream with a Channel Sediment Yield (CSY) of 174 tons/yr. The amount is high and can be attributed to the anthropogenic activities upstream. It is therefore recommended that the Ahmadu Bello University should intensify on their efforts in creating awareness among the academic and neighboring Samaru community on conservative methods of reducing the rate of pollution of the reservoir. Keywords: Dissolved Sediment, Discharge, Samaru Stream, Kubanni Reservoir, Ahmadu Bello University.
Exploring the elemental variations in commercial non-glutinous brown and white rice from Malaysia by chemometrics
No full textThe concentrations of Na, Mg, K, Ca, Mn, Fe, Cu, and Zn in a selection of commercial non-glutinous rice sampled from Malaysia were determined using microwave assisted digestion with inductively coupled plasma-mass spectrometry and the data obtained were evaluated using chemometric techniques. Both principal component analysis and hierarchical cluster analysis revealed two distinct clusters where the brown rice is associated with higher elemental content compared to the white rice; and Mg level was identified as a key discriminatory factor according to linear discriminant analysis outcomes. The concentrations of macroelements used to exhibit a consistent sequence: K > Mg > Ca > Na; whereas no regular trend was observed on the microelements. The results suggested that the elemental variations in the rice samples were largely attributed to the grain treatment processes while the impacts of the other underlying factors are more apparent on microelemental concentrations. From the nutritional assessment, brown rice appeared to be a noteworthy dietary source of Mg, Mn, and Zn, however, the contributions of Na and Ca to daily needs are negligible
Source identification and evaluation of surface water quality using factor and discriminant analysis
No full textThis study utilizes factor and discriminant analysis to identify the parameter source and evaluate the quality of water from ex-mining ponds and lakes in Selangor. Factor analysis (FA) which explain 83.77% of the surface water quality variation shows that As and Cd that mostly originated from mining activity, and pH are the parameters responsible for the major variation in the surface water quality and were strongly associated with varimax factor 1 (VF1), while Pb, Mn and DO were associated with varimax factor 2 (VF2). The Discriminant analysis (DA) reveals that As, Cd, Mn, Fe and pH are the parameters that significantly differentiate ex-mining ponds from the lake (p < 0.05 and F - ratio >> 1), and supported by the correlation study. The elevated metal concentrations in ex-mining ponds compared to lakes were plausibly associated with the past mining operation, thereby indicating heavy metal dominance in ex-mining ponds. DO and BOD are associated with the anthropogenic input from residential sources. Findings of this study therefore show the need and usefulness of multivariate statistical analysis to get information on the quality status of surface water.Keywords: Discriminant analysis, Ex-mining pond, Factor analysis, Lake, Water quality
Consumption of water from ex-mining ponds in Klang Valley and Melaka, Malaysia: A health risk study
No full textEvaluation of health risks due to heavy metals exposure via drinking water from ex-mining ponds in Klang Valley and Melaka has been conducted. Measurements of As, Cd, Pb, Mn, Fe, Na, Mg, Ca, and dissolved oxygen, pH, electrical conductivity, total dissolved solid, ammoniacal nitrogen, total suspended solid, biological oxygen demand were collected from 12 ex-mining ponds and 9 non-ex-mining lakes. Exploratory analysis identified As, Cd, and Pb as the most representative water quality parameters in the studied areas. The metal exposures were simulated using Monte Carlo methods and the associated health risks were estimated at 95th and 99th percentile. The results revealed that As was the major risk factor which might have originated from the previous mining activity. For Klang Valley, adults that ingested water from those ponds are at both non-carcinogenic and carcinogenic risks, while children are vulnerable to non-carcinogenic risk; for Melaka, only children are vulnerable to As complications. However, dermal exposure showed no potential health consequences on both adult and children groups
Consumption of water from ex-mining ponds in Klang Valley and Melaka, Malaysia: A health risk study
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