Displaying publications 61 - 80 of 509 in total

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  1. Vijith H, Dodge-Wan D
    Environ Monit Assess, 2019 Jul 13;191(8):494.
    PMID: 31302794 DOI: 10.1007/s10661-019-7604-z
    The upper catchment region of the Baram River in Sarawak (Malaysian Borneo) is undergoing severe land degradation due to soil erosion. Heavy rainfall with high erosive power has led to a number of soil erosion hotspots. The goal of the present study is to generate an understanding about the spatial characteristics of seasonal and annual rainfall erosivity (R), which not only control sediment delivery from the region but also determine the quantity of material potentially eroded. Mean annual rainfall and rainfall erosivity range from 2170 to 5167 mm and 1632 to 5319 MJ mm ha-1 h-1 year-1, respectively. Seasonal rainfall and rainfall erosivity range from 848 to 1872 mm and 558 to 1883 MJ mm ha-1 h-1 year-1 for the southwest (SW) monsoon, 902 to 2200 mm and 664 to 2793 MJ mm ha-1h-1year-1 for the northeast (NE) monsoon and 400 to 933 mm and 331 to 1075 MJ mm ha-1 h-1 year-1 during the inter-monsoon (IM) period. Linear regression, Spearman's Rho and Mann Kendall tests were applied. Considering the regional mean rainfall erosivity in the study area, all the methods show an overall non-significant decreasing trend (- 9.34, - 0.25 and - 0.30 MJ mm ha-1 h-1 year-1, respectively for linear regression, Spearman's Rho and Mann Kendall tests). However, during SW monsoon and IM periods, rainfall erosivity showed a non-significant decreasing trend (- 25.45, - 0.52, - 0.40, and - 8.86, - 1.07, - 0.77 MJ mm ha-1 h-1 year-1, respectively) whereas in NE, monsoon season erosivity showed a non-significant increasing trend (14.90, 1.59 and 1.60 MJ mm ha-1 h-1 year-1, respectively). The mean erosivity density ranges from 0.77 to 1.38 MJ ha-1 h-1 year-1 and shows decreasing trend. Spatial distribution pattern of erosivity density indicates significantly higher occurrence of erosive rainfall in the lower elevation portion of the study area. The spatial pattern of mean rainfall erosivity trends (linear, Spearman's Rho and Mann Kendall) suggests that the study area can be divided into two zones with increasing rainfall erosivity trends in the northern zone and decreasing trends in the southern zone. These results can be used to plan conservation measures to reduce sediment delivery from localized soil erosion hotspots.
    Matched MeSH terms: Rivers/chemistry*
  2. Venugopalan B, Nik Rubiah NAR, Meftahuddin T, Ayu M, Prema R, Ruhaini I, et al.
    Med J Malaysia, 2004 Dec;59(5):670-3.
    PMID: 15889571
    A Hepatitis A outbreak occurred in Mukim Hulu Langat, Hulu Langat district from April 2002 to October 2002. Of the 51 cases notified, most were among students and the ethnic groups involved were Malays and the Orang Asli (local indigenous community). Epidemiological investigations revealed that the cases were localized along rivers used for recreational activities in this area. River water analysis indicated human faecal contamination and it was believed that the contamination was due to the Orang Asli community living upstream. This occurred due to lack of toilet facilities, water at point of use and the existing traditional practices of the Orang Asli community. Control measures instituted were intense health education to the Orang Asli to avoid using the rivers for defecation, multi agency efforts to provide sanitary toilets and adequate water to the villages affected. Future measures include conducting a sero- prevalence survey to determine the feasibility of Hepatitis A immunization to the susceptible population in this area. The outbreak that began in April 2002 was controlled by October 2002.
    Matched MeSH terms: Rivers/virology
  3. Veerasingam SA, Ali Mohd M
    J Water Health, 2013 Jun;11(2):311-23.
    PMID: 23708578 DOI: 10.2166/wh.2013.151
    The presence of endocrine disruptors in source water is of great concern because of their suspected adverse effects on humans, even when present at very low levels. As the main source of potable water supply, rivers in Malaysia are highly susceptible to contamination by various endocrine disruptors originating from anthropogenic activities. In this study, the contamination levels of 1,1,1-trichloro-2,2-bis (4-chlorophenyl) ethane (DDT) and its metabolites and di-(2-ethylhexyl) phthalate (DEHP) in rivers of Selangor were examined using gas chromatography-mass spectrometry. Samples were collected from sites representing source water for 18 drinking water treatment plants in Selangor between July 2008 and July 2009. DDT and its metabolites were detected in only 14% of the 192 samples analysed at levels ranging from 0.6 to 14.6 ng/L. Meanwhile DEHP was detected in 96.8% of the samples at levels ranging from below quantitation level (18 ng/L) to 970 ng/L. The detected levels of DDTs and DEHP were lower than the WHO and Malaysian Guidelines for Drinking Water Quality. Data obtained from this study should also serve as a reference point for future surveillance on these endocrine disruptors.
    Matched MeSH terms: Rivers/chemistry
  4. Van Tung T, Tran QB, Phuong Thao NT, Vi LQ, Hieu TT, Le S, et al.
    Chemosphere, 2020 Dec 15;268:129329.
    PMID: 33360937 DOI: 10.1016/j.chemosphere.2020.129329
    This study develops a method to reuse aquaculture wastewater and sediment from a catfish pond in order to increase agricultural productivity and protect the environment. Material flow analysis (MFA) is a central concept of this study that involves collecting catfish pond wastewater (CPW) and reusing it to irrigate five water spinach (Ipomoea aquatic) ponds before discharging it into a river. Typically, catfish pond sediment (CPS) was collected and composted to produce organic fertilizer for cornfields. The results revealed that pollutant removal efficiency of wastewater from CPW (by using water spinach) were total organic carbon (TOC) = 38.78%, nitrogen (N) = 27.07%, phosphorous (P) = 58.42%, and potassium (K) = 28.64%. By adding 20 tons of CPS compost per hectare of the cornfield, the corn yield boosted 15% compared to the control field. In addition, the water spinach grew and developed well in the medium of wastewater from the fish pond. Altogether, the results illustrate that catfish pond wastewater and sediment can act as organic fertilizers for crops meanwhile reduce environmental pollution from its reuse.
    Matched MeSH terms: Rivers
  5. Valizadeh N, El-Shafie A, Mirzaei M, Galavi H, Mukhlisin M, Jaafar O
    ScientificWorldJournal, 2014;2014:432976.
    PMID: 24790567 DOI: 10.1155/2014/432976
    Water level forecasting is an essential topic in water management affecting reservoir operations and decision making. Recently, modern methods utilizing artificial intelligence, fuzzy logic, and combinations of these techniques have been used in hydrological applications because of their considerable ability to map an input-output pattern without requiring prior knowledge of the criteria influencing the forecasting procedure. The artificial neurofuzzy interface system (ANFIS) is one of the most accurate models used in water resource management. Because the membership functions (MFs) possess the characteristics of smoothness and mathematical components, each set of input data is able to yield the best result using a certain type of MF in the ANFIS models. The objective of this study is to define the different ANFIS model by applying different types of MFs for each type of input to forecast the water level in two case studies, the Klang Gates Dam and Rantau Panjang station on the Johor river in Malaysia, to compare the traditional ANFIS model with the new introduced one in two different situations, reservoir and stream, showing the new approach outweigh rather than the traditional one in both case studies. This objective is accomplished by evaluating the model fitness and performance in daily forecasting.
    Matched MeSH terms: Rivers*
  6. Valappil NKM, Viswanathan PM, Hamza V
    PMID: 32572749 DOI: 10.1007/s11356-020-09542-1
    A comprehensive study of the chemical composition of rainwater was carried out from October 2016 to September 2017 in the equatorial tropical rainforest region of northwestern Borneo. Monthly cumulative rainwater samples were collected from different locations in the Limbang River Basin (LRB) and were later categorized into seasonal samples representing northeast monsoon (NEM), southwest monsoon (SWM), and inter-monsoon (IM) periods. Physical parameters (pH, EC, TDS, DO, and turbidity), major ions (HCO3-, Cl-, Ca2+, Mg2+, Na+, and K+) and trace metals (Co, Ni, Cd, Fe, Mn, Pb, Zn, and Cu) were analyzed from collected rainwater samples. Rainwater is slightly alkaline with mean pH higher than 5.8. Chloride and bicarbonate are the most abundant ions, and the concentration of major ions in seasonal rainwater has shown slight variation which follows a descending order of HCO3-> Cl-> Na+ > Ca2+ > Mg2+ > K+ in NEM and Cl- > HCO3- > Na+ > Ca2+ > K+ > Mg2+ in SWM and Cl- > HCO3- > Na+ > Ca2+ > Mg2+ > K+ in IM period. Trace metals such as Fe and Ni have shown dominance in seasonal rainwater samples, and all the metals have shown variation in concentration in different seasons. Variation in chemical characteristic of seasonal rainwater samples identified through piper diagram indicates dominance of Ca2+-Mg2+-HCO3- and mixed Ca2+-Mg2+-Cl- facies during NEM, SWM, and IM periods. Statistical analysis of the results through two-way ANOVA and Pearson's correlation also indicates significant variation in physico-chemical characteristics. This suggests a variation in contributing sources during the monsoon seasons. Factor analysis confirmed the source variation by explaining the total variance of 79.80%, 90.72%, and 90.52% with three factor components in NEM, SWM, and IM rainwater samples with different loading of parameters. Enrichment factor analysis revealed a combined contribution of marine and crustal sources except K+ which was solely from crustal sources. Sample analysis of backward air mass trajectory supports all these findings by explaining seasonal variation in the source of pollutants reaching the study area. Overall, the results show that the chemical composition of seasonal rainwater samples in LRB was significantly influenced by natural as well as anthropogenic processes. These include (long-range and local) industrial activities, fossil fuel combustion, forest burning, transportation activities including road transport and shipping activities, and land-derived soil dust along with chemical constituents carried by seasonal wind.
    Matched MeSH terms: Rivers
  7. Vaezzadeh V, Zakaria MP, Shau-Hwai AT, Ibrahim ZZ, Mustafa S, Abootalebi-Jahromi F, et al.
    Mar Pollut Bull, 2015 Nov 15;100(1):311-320.
    PMID: 26323864 DOI: 10.1016/j.marpolbul.2015.08.034
    Peninsular Malaysia has gone through fast development during recent decades resulting in the release of large amounts of petroleum and its products into the environment. Aliphatic hydrocarbons are one of the major components of petroleum. Surface sediment samples were collected from five rivers along the west coast of Peninsular Malaysia and analyzed for aliphatic hydrocarbons. The total concentrations of C10 to C36 n-alkanes ranged from 27,945 to 254,463ng·g(-1)dry weight (dw). Evaluation of various n-alkane indices such as carbon preference index (CPI; 0.35 to 3.10) and average chain length (ACL; 26.74 to 29.23) of C25 to C33 n-alkanes indicated a predominance of petrogenic source n-alkanes in the lower parts of the Rivers, while biogenic origin n-alkanes from vascular plants are more predominant in the upper parts, especially in less polluted areas. Petrogenic sources of n-alkanes are predominantly heavy and degraded oil versus fresh oil inputs.
    Matched MeSH terms: Rivers
  8. Umar S, Shinkafi SH, Hudu SA, Neela V, Suresh K, Nordin SA, et al.
    Ann Parasitol, 2017;63(2):133-139.
    PMID: 28822206 DOI: 10.17420/ap6302.97
    Schistosomiasis is the major source of morbidity in Sub-Saharan Africa and Asia. It is estimated that 207 million people are infected, of which 97% are in Africa. The aim of this study was the determining of prevalence as well as the phylogeny of S. haematobium among school children in Argungu Emirate, Kebbi State Nigeria. A total of 325 urine samples was collected from school children between 7 to 14 years. S. heamatobium eggs was examined under dissecting microscope and DNA was extracted from urine sample and COX1 gene was amplified by nested PCR. The PCR products were purified, sequenced and analysed. This study showed a prevalence of 32.09%, with male pupils having the highest prevalence. S. haematobium infections in children who fetch water in the river have 24 times higher risk of being infected while those who bath in the river have 158 times higher risk of being infected. Our sequences were phylogenetically related to S. haematobium isolate U82266 from Kenya and consistence with the predominant species in Africa. This was the first S. haematobium and S. mansoni co-infection reported in Nigeria. S. haematobium infection is prevalent among school age and significantly associated with water contact.
    Matched MeSH terms: Rivers
  9. Umar HA, Abdul Khanan MF, Ogbonnaya C, Shiru MS, Ahmad A, Baba AI
    Heliyon, 2021 May;7(5):e06999.
    PMID: 34027190 DOI: 10.1016/j.heliyon.2021.e06999
    Over the years, pipelines have been the most economic medium for transporting crude oil to production and distribution facilities in the Niger Delta area of Nigeria. However, damages to the pipelines in this area by interdiction have hampered the continuous flow of crude oil to the facilities. Consequently, the revenue of the government dwindles, and the environment is severely degraded. This study assesses the economic and environmental impacts of pipeline interdiction in the Niger Delta region. Data from National oil spills detection and response agency, Nigeria is used to map spatial distribution of oil spills using Kernel Density Estimation with Geographic Information System. Literature was assessed to synthesize the historical, socioeconomic, and environmental impacts of oil spills and pipeline interdiction. Soil samples were collected from study area to determine the types of hydrocarbon pollutants and their concentrations in comparison with uncontaminated sites in the area. Results show that the range of concentrations of total petroleum hydrocarbon (TPH) for the impacted soil (IMP) was 17.27-58.36 mg/kg; remediated soil (RS) was 11.73-50.78 mg/kg which were higher than the concentrations of 0.68 mg/kg in the control samples (CS). Polycyclic aromatic hydrocarbons (PAH) concentrations were in the range of 0.43-77.54 mg/kg for IMP, 0.42-10.65 mg/kg for RS, against CS value of 0.49 mg/kg while BTEX ranged between 0.02 - 0.38 mg/kg for IMP, 0.01-2.7 for RS against CS value of 0.01. The values of the PAH were higher than the limits of the Department of Petroleum Resources, Nigeria. This study also revealed that pipeline interdiction has affected the livelihood of the inhabitants of the study area and the revenue of the Nigerian government. The major hotspots for oil spills in the Niger Delta region are Bayelsa, Rivers and Delta states.
    Matched MeSH terms: Rivers
  10. Uddin MR, Khandaker MU, Ahmed S, Abedin MJ, Hossain SMM, Al Mansur MA, et al.
    PLoS One, 2024;19(4):e0300878.
    PMID: 38635835 DOI: 10.1371/journal.pone.0300878
    Saltwater intrusion in the coastal areas of Bangladesh is a prevalent phenomenon. However, it is not conducive to activities such as irrigation, navigation, fish spawning and shelter, and industrial usage. The present study analyzed 45 water samples collected from 15 locations in coastal areas during three seasons: monsoon, pre-monsoon, and post-monsoon. The aim was to comprehend the seasonal variation in physicochemical parameters, including water temperature, pH, electrical conductivity (EC), salinity, total dissolved solids (TDS), hardness, and concentrations of Na+, K+, Mg2+, Ca2+, Fe2+, HCO3-, PO43-, SO42-, and Cl-. Additionally, parameters essential for agriculture, such as soluble sodium percentage (SSP), sodium absorption ratio (SAR), magnesium absorption ratio (MAR), residual sodium carbonate (RSC), Kelly's ratio (KR), and permeability index (PI), were examined. Their respective values were found to be 63%, 16.83 mg/L, 34.92 mg/L, 145.44 mg/L, 1.28 mg/L, and 89.29%. The integrated water quality index was determined using entropy theory and principal component analysis (PCA). The resulting entropy water quality index (EWQI) and SAR of 49.56% and 63%, respectively, indicated that the samples are suitable for drinking but unsuitable for irrigation. These findings can assist policymakers in implementing the Bangladesh Deltaplan-2100, focusing on sustainable land management, fish cultivation, agricultural production, environmental preservation, water resource management, and environmental protection in the deltaic areas of Bangladesh. This research contributes to a deeper understanding of seasonal variations in the hydrochemistry and water quality of coastal rivers, aiding in the comprehension of salinity intrusion origins, mechanisms, and causes.
    Matched MeSH terms: Rivers
  11. Tunbosun, Olawumi Edward, Rampal, Lekhraj, Hejar Abdul Rahman, Roslaini Abdul Majid
    MyJurnal
    Introduction: Worm infection is one of the major global public health problems especially among rural communities.
    Objectives: to determine the prevalence of intestinal worm infection and factors associated among Semai Aboriginal
    children aged between 6 to 13 years in Tapah, Malaysia. Methods: A cross-sectional study design was used in this
    study. The estimated sample size was 508. Data was collected using a validated pretested questionnaire. Faecal
    samples were also examined. Data was analysed using SPSS version 22. Results: The response rate was 80.9%.
    The overall mean age of the 411 respondents was 10.1 years(95% CI = 9.89, 10.22). Majority (71.5%) were poor.
    Prevalence of intestinal worm infections was 60.8% and 57.2% had multiple infections. The multiple logistic
    regression analysis showed that those with poor hygiene practices were 2.18 times the odds of worm infection
    when compared with children with good hygiene practices (95% CI = 1.4, 3.4). Similarly, poor attitudes towards
    prevention of worm infection increased the odds of having worm infection by 1.62 times among Orang Asli children.
    Children living without toilets had 2.45 times higher odds as compared with those who had proper toilets. Absence
    of river near by these areas where there is no safe water supply also increases the risk of worm infection among
    children by 1.84 times among Orang Asli children. Conclusions: the prevalence of worm infection is still very
    high among rural Aboriginal community. Current control measures should be reassessed to enable introduction of
    effective measures to reduce the worm infection among Orang Asli children.
    Matched MeSH terms: Rivers
  12. Tosin OV, Gabriel SS, Wukatda SS, Simon I, Mhd I, Bolong AA
    Trop Life Sci Res, 2021 Mar;32(1):163-174.
    PMID: 33936557 DOI: 10.21315/tlsr2021.32.1.10
    The body characteristics and yield indices of Clarias gariepinus, Bagrus bajad, Synodontis nigrita, Labeo senegalensis and Mormyrus rume from lower Benue River in Nigeria were determined in this study using 60 samples each for the fish species. Length, weight and fillet correlations were also determined during the study. Results obtained showed that M. rume, L. senegalensis and C. gariepinus had the highest percentage of edible parts (≥ 55%) compared to the other species (≤ 39%). Concerning correlations of the fillet with the morphological variables, results obtained suggest that fillet yield is independent of fish size (except for C. gariepinus which was positively correlated). Also, only samples of L. senegalensis showed isometric growth pattern; the other fish species had either positive (C. gariepinus and B. bajad) or negative (S. nigrita and M. rume) allometric growth. While the difference in fillet yield and body characteristics was attributed to the structural anatomy and other biological dynamics of the fishes, this study could not establish a connection between fillet yield and the length-weight relationship. It was concluded that M. rume, L. senegalensis and C. gariepinus would be better export products because of their higher fillet yields.
    Matched MeSH terms: Rivers
  13. Tingga RCT, Anwarali F, Mohd Ridwan A, M. T. Abdullah M, Senawi J
    Sains Malaysiana, 2012;41:659-669.
    A faunal survey aimed to document small mammals was conducted at Nature Study Centre of Kuala Atok, Taman Negara Pahang from 16th to 23rd May 2008. This survey was part of the Biodiversity Inventory Programme that was organised by the Department of Wildlife and National Parks (DWNP). On average, ten mist nets, two four-bank harp traps, 100 cage traps and 40 Sherman traps were set for six trapping nights. A total of 79 individuals from three orders, seven families and 23 species were caught in this study. Of the 23 species, three were frugivorous bats, 15 were insectivorous bats, four were rodents and one was treeshrew. Our sampling site was bounded by Pahang River and mainly covered with lowland secondary forest. This is evidence by the highest abundance of Long-tailed Giant Rat (Leopoldamys sabanus) for non-volant small mammals, and Fawn Roundleaf Bat (Hipposideros cervinus) for volant small mammals that are adapted to disturbed habitat. The increasing species cumulative curve for Chiropteran indicates that there may be more species yet to be recorded from this study site compared to rodents and treeshrews. Preliminary analysis on the species similarity between our study site to other survey reports in Peninsular Malaysia, positioned Kuala Atok with Krau Wildlife Reserve and Bukit Fraser Forest Reserve that are located adjacent to our study site. This similarity further indicate the
    importance of future survey in Kuala Atok especially for Chiropterans to properly document the species diversity in this site that may be as rich as other well studied area e.g. Krau Wildlife Reserve.
    Matched MeSH terms: Rivers
  14. Thamer Ahmed Mohammed, Abdul Halim Ghazali, Al-Hassoun, Saleh
    MyJurnal
    Malaysia is a tropical country and it is subjected to flooding in both the urban and rural areas. Flood
    modelling can help to reduce the impacts of flood hazard by taking extra precautions. HEC-RAS model was used to predict the flood levels at selected reach of the Langat River with a total length of 34.4 km. The Langat River is located in the state of Selangor, Malaysia and it is subjected to regular flooding. The selected reach of the Langat River has insufficient data and a methodology was proposed to overcome this particular problem. Since complete floodplain data for the area are not available, the modelling therefore assumed vertical walls at the left and right banks of the Langat River and all the predicted flood levels above the banks were based on this assumption. The HECRAS model was calibrated and the values of Manning’s coefficients of roughness for the Langat River were found to range from 0.04 to 0.10. The discharge values were calculated for 5, 10, 25, 50, and 100 year return periods and the maximum predicted flood depth ranged from 2.1m to 7.8m. Meanwhile, the model output was verified using the historical record and the error between the recorded and predicted water levels was found to range from 3% to 15%.
    Matched MeSH terms: Rivers
  15. Tengku Ariff, R.H., Mohd Nazi, M.Z., Mohd Rizam, M.Z., Mohd Shahriman, M.S., Zakaria, Y., Kamal Nazmir, K., et al.
    MyJurnal
    This study was conducted to determine the health status of aboriginal ("Orang Asli') children aged 0-12 years in Post Brooke, Gua Musang, Kelantan. This is done by appraising the environmental status, patterns of illnesses including communicable diseases and usage of health resources. Six villages were selected randomly from 12 villages in the area; 179 families were interviewed, 200 under-12-year-olds were examined and their blood samples taken for haemoglobin (HB) estimation as well as malarial screening. Water supply through Gravity Feed System (GFS) was used by 134 families (70.2%) whilst the rest obtained water direct from the river for the purpose. Only 63.6% of families boiled their drinking water 56.4% families threw rubbish indiscriminately, while 82.1% used the river as their toilets. Eighty-seven percent of the families saw the village medicine man first when ill. Forty (22.2%) children had had serious illnesses including malaria and 24 were admitted to hospitals. 15% of the children had never been immunized. A total of 102 (51%) children were pale and 90 (45%) had brown hair. Eighty nine (44.5%) of the children were anaemic (Hb < 10 gm/di). Sixty-nine children (34%) had dental caries. Forty-two (21%) had distended abdomen and 37 (18.5%) had hepatomegaly. Out of 84 stool samples examined, 67 (79.8%) had helminthic ova. Of all families, 47.1% gave a past history of at least one baby among their children who had died due to one reason or another. The health status of this community (especially children) was low that it warrants special attention.
    Matched MeSH terms: Rivers
  16. Taweel A, Shuhaimi-Othman M, Ahmad AK
    Ecotoxicol Environ Saf, 2013 Jul;93:45-51.
    PMID: 23642778 DOI: 10.1016/j.ecoenv.2013.03.031
    Concentrations of the heavy metals copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb) and nickel (Ni) were determined in the liver, gills and muscles of tilapia fish from the Langat River and Engineering Lake, Bangi, Selangor, Malaysia. There were differences in the concentrations of the studied heavy metals between different organs and between sites. In the liver samples, Cu>Zn>Ni>Pb>Cd, and in the gills and muscle, Zn>Ni>Cu>Pb>Cd. Levels of Cu, Cd, Zn and Pb in the liver samples from Engineering Lake were higher than in those from the Langat River, whereas the Ni levels in the liver samples from the Langat River were greater than in those from Engineering Lake. Cd levels in the fish muscle from Engineering Lake were lower than in that from the Langat River. Meanwhile, the Cd, Zn and Pb levels in the fish muscle from the Langat River were lower than in that from Engineering Lake, and the Ni levels were almost the same in the fish muscle samples from the two sites. The health risks associated with Cu, Cd, Zn, Pb and Ni were assessed based on the target hazard quotients. In the Langat River, the risk from Cu is minimal compared to the other studied elements, and the concentrations of Pb and Ni were determined to pose the greatest risk. The maximum allowable fish consumption rates (kg/d) based on Cu in Engineering Lake and the Langat River were 2.27 and 1.51 in December and 2.53 and 1.75 in February, respectively. The Cu concentrations resulted in the highest maximum allowable fish consumption rates compared with the other studied heavy metals, whereas those based on Pb were the lowest. A health risk analysis of the heavy metals measured in the fish muscle samples indicated that the fish can be classified at one of the safest levels for the general population and that there are no possible risks pertaining to tilapia fish consumption.
    Matched MeSH terms: Rivers/chemistry
  17. Tashakor M, Modabberi S, van der Ent A, Echevarria G
    Environ Monit Assess, 2018 May 08;190(6):333.
    PMID: 29737421 DOI: 10.1007/s10661-018-6668-5
    This study focused on the influence of ultramafic terrains on soil and surface water environmental chemistry in Peninsular Malaysia and in the State of Sabah also in Malaysia. The sampling included 27 soils from four isolated outcrops at Cheroh, Bentong, Bukit Rokan, and Petasih from Peninsular Malaysia and sites near Ranau in Sabah. Water samples were also collected from rivers and subsurface waters interacting with the ultramafic bodies in these study sites. Physico-chemical parameters (including pH, EC, CEC) as well as the concentration of major and trace elements were measured in these soils and waters. Geochemical indices (geoaccumulation index, enrichment factor, and concentration factor) were calculated. Al2O3 and Fe2O3 had relatively high concentrations in the samples. A depletion in MgO, CaO, and Na2O was observed as a result of leaching in tropical climate, and in relation to weathering and pedogenesis processes. Chromium, Ni, and Co were enriched and confirmed by the significant values obtained for Igeo, EF, and CF, which correspond to the extreme levels of contamination for Cr and high to moderate levels of contamination for Ni and Co. The concentrations of Cr, Ni, and Co in surface waters did not reflect the local geochemistry and were within the permissible ranges according to WHO and INWQS standards. Subsurface waters were strongly enriched by these elements and exceeded these standards. The association between Cr and Ni was confirmed by factor analysis. The unexpected enrichment of Cu in an isolated component can be explained by localized mineralization in Sabah.
    Matched MeSH terms: Rivers/chemistry
  18. Tao H, Al-Hilali AA, Ahmed AM, Mussa ZH, Falah MW, Abed SA, et al.
    Chemosphere, 2023 Mar;317:137914.
    PMID: 36682637 DOI: 10.1016/j.chemosphere.2023.137914
    Heavy metals (HMs) are a vital elements for investigating the pollutant level of sediments and water bodies. The Murray-Darling river basin area located in Australia is experiencing severe damage to increased crop productivity, loss of soil fertility, and pollution levels within the vicinity of the river system. This basin is the most effective primary production area in Australia where agricultural productivity is increased the gross domastic product in the entire mainland. In this study, HMs contaminations are examined for eight study sites selected for the Murray-Darling river basin where the inverse Distance Weighting interpolation method is used to identify the distribution of HMs. To pursue this, four different pollution indices namely the Geo-accumulation index (Igeo), Contamination factor (CF), Pollution load index (PLI), single-factor pollution index (SPLI), and the heavy metal pollution index (HPI) are computed. Following this, the Pearson correlation matrix is used to identify the relationships among the two HM parameters. The results indicate that the conductivity and N (%) are relatively high in respect to using Igeo and PLI indexes for study sites 4, 6, and 7 with 2.93, 3.20, and 1.38, respectively. The average HPI is 216.9071 that also indicates higher level pollution in the Murray-Darling river basin and the highest HPI value is noted in sample site 1 (353.5817). The study also shows that the levels of Co, P, Conductivity, Al, and Mn are mostly affected by HMs and that these indices indicate the maximum HM pollution level in the Murray-Darling river basin. Finally, the results show that the high HM contamination level appears to influence human health and local environmental conditions.
    Matched MeSH terms: Rivers
  19. Tao H, Bobaker AM, Ramal MM, Yaseen ZM, Hossain MS, Shahid S
    Environ Sci Pollut Res Int, 2019 Jan;26(1):923-937.
    PMID: 30421367 DOI: 10.1007/s11356-018-3663-x
    Surface and ground water resources are highly sensitive aquatic systems to contaminants due to their accessibility to multiple-point and non-point sources of pollutions. Determination of water quality variables using mathematical models instead of laboratory experiments can have venerable significance in term of the environmental prospective. In this research, application of a new developed hybrid response surface method (HRSM) which is a modified model of the existing response surface model (RSM) is proposed for the first time to predict biochemical oxygen demand (BOD) and dissolved oxygen (DO) in Euphrates River, Iraq. The model was constructed using various physical and chemical variables including water temperature (T), turbidity, power of hydrogen (pH), electrical conductivity (EC), alkalinity, calcium (Ca), chemical oxygen demand (COD), sulfate (SO4), total dissolved solids (TDS), and total suspended solids (TSS) as input attributes. The monthly water quality sampling data for the period 2004-2013 was considered for structuring the input-output pattern required for the development of the models. An advance analysis was conducted to comprehend the correlation between the predictors and predictand. The prediction performances of HRSM were compared with that of support vector regression (SVR) model which is one of the most predominate applied machine learning approaches of the state-of-the-art for water quality prediction. The results indicated a very optimistic modeling accuracy of the proposed HRSM model to predict BOD and DO. Furthermore, the results showed a robust alternative mathematical model for determining water quality particularly in a data scarce region like Iraq.
    Matched MeSH terms: Rivers
  20. Tan WT, Tan GS, Nather Khan IS
    Environ Pollut, 1988;52(3):221-35.
    PMID: 15092608
    Chemical forms of copper and lead in river water of the Linggi River Basin have been fractionated into ASV labile, moderately labile, slowly labile, and inert metal species, based on a previously proposed scheme. Free (hydrated) metal ions were identified by a potentiometric method using an ion selective electrode. Speciation results showed that the soluble copper and lead species occurred mainly in the moderately labile and slowly labile fractions. The speciation results are primarily interpreted in terms of organic interaction due to agricultural based and light industries, and urban discharges. The measured metal complexing capacity (MCC) of the samples reveals consistency of the results with the nature of the discharge. MCC correlates reasonably well with the value from the permanganate test on the river water. In general, the speciation pattern was found to be consistent with the findings of other workers.
    Matched MeSH terms: Rivers
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