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Surfactants in atmospheric aerosols and rainwater around lake ecosystem

Razak IS, Latif MT, Jaafar SA, Khan MF, Mushrifah I

Environ Sci Pollut Res Int, 2015 Apr;22(8):6024-33.
PMID: 25382497 DOI: 10.1007/s11356-014-3781-z

This study was conducted to determine the composition of surfactants in atmospheric aerosols and rainwater in the vicinity of Lake Chini, Malaysia. Samples of atmospheric aerosol and rainwater were collected between March and September 2011 using a high volume air sampler (HVAS) and glass bottles equipped with funnel. Colorimetric analysis was undertaken to determine the concentration of anionic surfactants as methylene blue active substances (MBAS) and cationic surfactants as disulphine blue active substances (DBAS). The water-soluble ionic compositions were determined using inductively coupled plasma mass spectrometry for cations (Na, K, Mg and Ca) and ion chromatography equipped with a conductivity detector for anions (F(-), Cl(-), NO3(-), and SO4(2-)) and the Nessler Method was used to obtain the NH4(+) concentrations. The source apportionment of MBAS and DBAS in atmospheric aerosols was identified using a combination of principal component analysis (PCA) and multiple linear regression (MLR). The results revealed that the concentrations of surfactants in atmospheric aerosols and rainwater were dominated by anionic surfactants as MBAS. The concentration of surfactants as MBAS and DBAS was dominated in fine mode compared to coarse mode aerosols. Using PCA/MLR analysis, two major sources of atmospheric surfactants to Lake Chini were identified as soil dust (75 to 93%) and biomass burning (2 to 22%).
Polycyclic aromatic hydrocarbons in coastal sediments of Southern Terengganu, South China Sea, Malaysia: source assessment using diagnostic ratios and multivariate statistic

Pang SY, Suratman S, Latif MT, Khan MF, Simoneit BRT, Mohd Tahir N

Environ Sci Pollut Res Int, 2022 Mar;29(11):15849-15862.
PMID: 34636003 DOI: 10.1007/s11356-021-16762-6

Surface sediments along the Southern Terengganu coast (≤7 km from the coast) were analyzed for polycyclic aromatic hydrocarbons (PAHs). The concentrations of 16 USEPA priority polycyclic aromatic hydrocarbons (ΣPAH16) ranged from 2.59 to 155 ng g-1 and their respective alkylated ranged between 8.80 and 24.90 ng g-1. Traces of acephenanthrylene, benzo[c]phenanthrene, thiophenic PAH, and benzonaphthofuran were identified. PAH diagnostic ratios and cross-plots revealed that these sedimentary PAH compounds are derived mainly from pyrogenic sources, primarily from biomass burning and petroleum combustion residues with minor petrogenic input. The high correlations between pyrogenic PAHs to total PAHs (r >0.73, p <0.5), and the Bap/Bep ratio to total PAHs (r = 0.88, p <0.5), suggest that atmospheric deposition and urban runoff are the main deposition pathways. The concentrations of the PAHs in the southern South China Sea fall in the moderate contamination range of 100-1000 ng g-1.
The association between temperature and cause-specific mortality in the Klang Valley, Malaysia

Yatim ANM, Latif MT, Sofwan NM, Ahamad F, Khan MF, Mahiyuddin WRW, et al.

Environ Sci Pollut Res Int, 2021 Nov;28(42):60209-60220.
PMID: 34156627 DOI: 10.1007/s11356-021-14962-8

This study aims to examine the relationship between daily temperature and mortality in the Klang Valley, Malaysia, over the period 2006-2015. A quasi-Poisson generalized linear model combined with a distributed lag non-linear model (DLNM) was used to estimate the association between the mean temperature and mortality categories (natural n=69,542, cardiovascular n= 15,581, and respiratory disease n=10,119). Particulate matter with an aerodynamic diameter below 10 μm (PM10) and surface ozone (O3) was adjusted as a potential confounding factor. The relative risk (RR) of natural mortality associated with extreme cold temperature (1st percentile of temperature, 25.2 °C) over lags 0-28 days was 1.26 (95% confidence interval (CI): 1.00, 1.60), compared with the minimum mortality temperature (28.2 °C). The relative risk associated with extremely hot temperature (99th percentile of temperature, 30.2 °C) over lags 0-3 days was 1.09 (95% CI: 1.02, 1.17). Heat effects were immediate whereas cold effects were delayed and lasted longer. People with respiratory diseases, the elderly, and women were the most vulnerable groups when it came to the effects of extremely high temperatures. Extreme temperatures did not dramatically change the temperature-mortality risk estimates made before and after adjustments for air pollutant (PM10 and O3) levels.
Fulltext The long-term assessment of air quality on an island in Malaysia

Abdul Halim ND, Latif MT, Ahamad F, Dominick D, Chung JX, Juneng L, et al.

Heliyon, 2018 Dec;4(12):e01054.
PMID: 30603693 DOI: 10.1016/j.heliyon.2018.e01054

This study aims to evaluate the air quality on Langkawi Island, a famous tourist destination in Malaysia, using 13 years of data (1999-2011) recorded by the Malaysian Department of Environment. Variations of seven air pollutants (O3, CO, NO, NO2, NOx, SO2 and PM10) and three meteorological factors (temperature, humidity and wind speed) were analysed. Statistical methods used to analyse the data included principal component regression (PCR) and sensitivity analysis. The results showed PM10 was the dominant air pollutant in Langkawi and values ranged between 5.0 μg m-3 and 183.2 μg m-3. The patterns of monthly values showed that the concentrations of measured air pollutants on Langkawi were higher during the south-west monsoon (June-September) due to seasonal biomass burning activities. High CO/NOx ratio values (between 28.3 and 43.6), low SO2/NOx ratio values (between 0.04 and 0.12) and NO/NO2 ratio values exceeding 2.2 indicate the source of air pollutants in this area was motor vehicles. PCR analysis grouped the seven variables into two factor components: the F1 component consisted of SO2, NO and NOx and the F2 component consisted of PM10. The F1 component (R2 = 0.931) indicated a stronger standardized coefficient value for meteorological variables compared to the F2 component (R2 = 0.059). The meteorological variables were statistically significant (p < 0.05) in influencing the distribution of the air pollutants. The status of air quality on the island could be improved through control on motor vehicle emissions as well as collaborative efforts to reduce regional air pollution, especially from biomass burning.
Ecological risk and source apportionment of heavy metals in surface water and sediments on Saint Martin's Island in the Bay of Bengal

Sarker KK, Bristy MS, Alam N, Baki MA, Shojib FH, Quraishi SB, et al.

Environ Sci Pollut Res Int, 2020 Sep;27(25):31827-31840.
PMID: 32504432 DOI: 10.1007/s11356-020-09384-x

The study aimed to determine eight hazardous heavy metals in surface water and sediment samples collected from the Naf River, Shah Porir Dwip (estuary), and mostly around Saint Martin's Island in the Bay of Bengal. The results of heavy metals in water samples were ranged as Pb 14.7-313.0, Cd 33.0-70.0, Cr
Sterols as biomarkers in the surface microlayer of the estuarine areas

Alsalahi MA, Latif MT, Ali MM, Dominick D, Khan MF, Mustaffa NI, et al.

Mar Pollut Bull, 2015 Apr 15;93(1-2):278-83.
PMID: 25682566 DOI: 10.1016/j.marpolbul.2015.01.011

This study aims to determine the concentration of sterols used as biomarkers in the surface microlayer (SML) in estuarine areas of the Selangor River, Malaysia. Samples were collected during different seasons through the use of a rotation drum. The analysis of sterols was performed using gas chromatography equipped with a flame ionisation detector (GC-FID). The results showed that the concentrations of total sterols in the SML ranged from 107.06 to 505.55 ng L(-1). The total sterol concentration was found to be higher in the wet season. Cholesterol was found to be the most abundant sterols component in the SML. The diagnostic ratios of sterols show the influence of natural sources and waste on the contribution of sterols in the SML. Further analysis, using principal component analysis (PCA), showed distinct inputs of sterols derived from human activity (40.58%), terrigenous and plant inputs (22.59%) as well as phytoplankton and marine inputs (17.35%).
Surfactants in the sea-surface microlayer and atmospheric aerosol around the southern region of Peninsular Malaysia

Jaafar SA, Latif MT, Chian CW, Han WS, Wahid NB, Razak IS, et al.

Mar Pollut Bull, 2014 Jul 15;84(1-2):35-43.
PMID: 24930738 DOI: 10.1016/j.marpolbul.2014.05.047

This study was conducted to determine the composition of surfactants in the sea-surface microlayer (SML) and atmospheric aerosol around the southern region of the Peninsular Malaysia. Surfactants in samples taken from the SML and atmospheric aerosol were determined using a colorimetric method, as either methylene blue active substances (MBAS) or disulphine blue active substances (DBAS). Principal component analysis with multiple linear regressions (PCA-MLR), using the anion and major element composition of the aerosol samples, was used to determine possible sources of surfactants in atmospheric aerosol. The results showed that the concentrations of surfactants in the SML and atmospheric aerosol were dominated by anionic surfactants and that surfactants in aerosol were not directly correlated (p>0.05) with surfactants in the SML. Further PCA-MLR from anion and major element concentrations showed that combustion of fossil fuel and sea spray were the major contributors to surfactants in aerosol in the study area.
Mercury in dental amalgam: Are our health care workers at risk?

Sahani M, Sulaiman NS, Tan BS, Yahya NA, Anual ZF, Mahiyuddin WR, et al.

J Air Waste Manag Assoc, 2016 Nov;66(11):1077-1083.
PMID: 27192328 DOI: 10.1080/10962247.2016.1188866

Dental amalgam in fillings exposes workers to mercury. The exposure to mercury was investigated among 1871 dental health care workers. The aim of the study was to evaluate the risk of mercury exposure among dental compared to nondental health care workers and to determine other risk factors for mercury exposure. Respondents answered questionnaires to obtain demographic, personal, professional, and workplace information and were examined for their own amalgam fillings. Chronic mercury exposure was assessed through urinary mercury levels. In total, 1409 dental and 462 nondental health care workers participated in the study. Median urine mercury levels for dental and nondental health care workers were 2.75 μg/L (interquartile range [IQR] = 3.0175) and 2.66 μg/L (IQR = 3.04) respectively. For mercury exposure, there were no significant risk factor found among the workers involved within the dental care. The Mann-Whitney test showed that urine mercury levels were significantly different between respondents who eat seafood more than 5 times per week compared to those who eat it less frequently or not at all (p = 0.003). The urinary mercury levels indicated significant difference between dental workers in their practice using squeeze cloths (Mann-Whitney test, p = 0.03). Multiple logistic regression showed that only the usage of cosmetic products that might contain mercury was found to be significantly associated with the urinary mercury levels (odds ratio [OR] = 15.237; CI: 3.612-64.276). Therefore, mean urinary mercury levels of health care workers were low. Exposure to dental amalgam is not associated with high mercury exposure. However, usage of cosmetic products containing mercury and high seafood consumption may lead to the increase of exposure to mercury.

IMPLICATIONS: Exposure to the high levels of mercury from dental amalgam can lead to serious health effects among the dental health care workers. Nationwide chronic mercury exposure among dental personnel was assessed through urinary mercury levels. Findings suggest low urinary mercury levels of these health care workers. Exposure to dental amalgam is not associated with high mercury exposure. However, the usage of cosmetic products containing mercury and high seafood consumption may lead to the increase of exposure to mercury.
Risk of concentrations of major air pollutants on the prevalence of cardiovascular and respiratory diseases in urbanized area of Kuala Lumpur, Malaysia

Tajudin MABA, Khan MF, Mahiyuddin WRW, Hod R, Latif MT, Hamid AH, et al.

Ecotoxicol Environ Saf, 2019 Apr 30;171:290-300.
PMID: 30612017 DOI: 10.1016/j.ecoenv.2018.12.057

Rapid urbanisation in Malaysian cities poses risks to the health of residents. This study aims to estimate the relative risk (RR) of major air pollutants on cardiovascular and respiratory hospitalisations in Kuala Lumpur. Daily hospitalisations due to cardiovascular and respiratory diseases from 2010 to 2014 were obtained from the Hospital Canselor Tuanku Muhriz (HCTM). The trace gases, PM10 and weather variables were obtained from the Department of Environment (DOE) Malaysia in consistent with the hospitalisation data. The RR was estimated using a Generalised Additive Model (GAM) based on Poisson regression. A "lag" concept was used where the analysis was segregated into risks of immediate exposure (lag 0) until exposure after 5 days (lag 5). The results showed that the gases could pose significant risks towards cardiovascular and respiratory hospitalisations. However, the RR value of PM10 was not significant in this study. Immediate effects on cardiovascular hospitalisations were observed for NO2 and O3 but no immediate effect was found on respiratory hospitalisations. Delayed effects on cardiovascular and respiratory hospitalisations were found with SO2 and NO2. The highest RR value was observed at lag 4 for respiratory admissions with SO2 (RR = 1.123, 95% CI = 1.045-1.207), followed by NO2 at lag 5 for cardiovascular admissions (RR = 1.025, 95% CI = 1.005-1.046). For the multi-pollutant model, NO2 at lag 5 showed the highest risks towards cardiovascular hospitalisations after controlling for O3 8 h mean lag 1 (RR = 1.026, 95% CI = 1.006-1.047), while SO2 at lag 4 showed highest risks towards respiratory hospitalisations after controlling for NO2 lag 3 (RR = 1.132, 95% CI = 1.053-1.216). This study indicated that exposure to trace gases in Kuala Lumpur could lead to both immediate and delayed effects on cardiovascular and respiratory hospitalisations.
Health risk assessment of heavy metal accumulation in the Buriganga and Turag River systems for Puntius ticto, Heteropneustes fossilis, and Channa punctatus

Baki MA, Shojib MFH, Sehrin S, Chakraborty S, Choudhury TR, Bristy MS, et al.

Environ Geochem Health, 2020 Feb;42(2):531-543.
PMID: 31376046 DOI: 10.1007/s10653-019-00386-4

This study aimed to assess the effects of major ecotoxic heavy metals accumulated in the Buriganga and Turag River systems on the liver, kidney, intestine, and muscle of common edible fish species Puntius ticto, Heteropneustes fossilis, and Channa punctatus and determine the associated health risks. K was the predominant and reported as a major element. A large concentration of Zn was detected in diverse organs of the three edible fishes compared with other metals. Overall, trace metal analysis indicated that all organs (especially the liver and kidney) were under extreme threat because the maximum permissible limit set by different international health organizations was exceeded. The target hazard quotient and target cancer risk due to the trace metal content were the largest for P. ticto. Thus, excessive intake of P. ticto from the rivers Buriganga and Turag could result in chronic risks associated with long-term exposure to contaminants. Histopathological investigations revealed the first detectable indicators of infection and findings of long-term injury in cells, tissues, and organs. Histopathological changes in various tissue structures of fish functioned as key pointers of connection to pollutants, and definite infections and lesion types were established based on biotic pointers of toxic/carcinogenic effects. The analysis of histopathological alterations is a controlling integrative device used to assess pollutants in the environment.
Pharmacological insights on the antidepressant, anxiolytic and aphrodisiac potentials of Aglaonema hookerianum Schott

Goni O, Khan MF, Rahman MM, Hasan MZ, Kader FB, Sazzad N, et al.

J Ethnopharmacol, 2021 Mar 25;268:113664.
PMID: 33278545 DOI: 10.1016/j.jep.2020.113664

ETHNOPHARMACOLOGICAL RELEVANCE: Aglaonema hookerianum Schott is an ethnomedicinally important plant used to treat a variety of diseases, including sexual and depression-like disorders. However, the scientific basis underlying the aforesaid properties have not been well justified.
AIM OF THE STUDY: The present investigation aimed to investigate the anxiolytic, antidepressant and aphrodisiac potentials of methanol leaves extract of A. hookerianum (MEAH) in Swiss albino mice.
MATERIALS & METHODS: Swiss albino mice (20-30 g) were orally administrated with MEAH at the doses ranging from 100 to 400 mg/kg, b.w. The elevated plus maze (EPM) and hole board test (HBT) were performed to determine the anxiolytic activity and the forced swimming test (FST) and tail suspension test (TST) were performed to determine the antidepressant activity of MEAH. Besides, the aphrodisiac activity of MEAH was conducted through the mounting behaviour and orientation behaviour analysis. Diazepam (1 mg/kg, b.w., i.p.) for EPM and HBT; fluoxetine HCl (20 mg/kg, b.w., p.o.) for FST and TST, and sildenafil (5 mg/kg, b.w., p.o.) for the mounting behaviour analysis and orientation behaviour analysis were used as reference drugs.
RESULTS: The administration of the MEAH produced a strong (p
Concentration of heavy metals in seafood (fishes, shrimp, lobster and crabs) and human health assessment in Saint Martin Island, Bangladesh

Baki MA, Hossain MM, Akter J, Quraishi SB, Haque Shojib MF, Atique Ullah AKM, et al.

Ecotoxicol Environ Saf, 2018 Sep 15;159:153-163.
PMID: 29747150 DOI: 10.1016/j.ecoenv.2018.04.035

A contaminated aquatic environment may end up in the food chain and pose risks to tourist health in a tourist destination. To assess the health risk for tourists that visit St. Martine Island, which is a popular domestic and foreign tourist destination in Bangladesh, a study is undertaken to analyse the level of heavy metal contamination from chromium (Cr), manganese (Mn), copper (Cu), zinc (Zn), arsenic (As), cadmium (Cd), lead (Pb), mercury (Hg) and iron (Fe) in six of the most consumed fish (L. fasciatus, R. kanagurta, H. nigrescens, P. cuneatus, P. annularis and S. rubrum) and five crustacean species, which consist of a shrimp (P. sculptilis), a lobster (P. versicolor) and three crabs (P. sanguinolentus, T. crenata and M. victor) captured. The samples were analysed for trace metals using atomic absorption spectrometer, and the concentrations of the metals were interpreted using the United State Environmental Protection Agency (USEPA) health risk model. The muscle and carapace/exoskeleton of shrimp, lobster and crabs were analysed and contained various concentrations of Pb, Hg, As, Cr, Cd, Fe, Cu, Zn and Mn. The hierarchy of the heavy metal in marine fish is Fe > Cd > Zn > Pb > Cu > Cr > Mn > Hg. The concentrations of Pb in the species R. kanagurta, H. nigresceus and S. rubrum were above the food safety guideline by Australia, New Zealand and other legislations in most marine fish and crustaceans. Crabs showed higher mean heavy metal concentrations than shrimp and lobster. Acceptable carcinogen ranges were observed in three fish species (R. kanagurata, H. nigresceus and S. rubrum) and one crustacean species (P. sculptilis) samples.
Source apportionment and health risk assessment among specific age groups during haze and non-haze episodes in Kuala Lumpur, Malaysia

Sulong NA, Latif MT, Khan MF, Amil N, Ashfold MJ, Wahab MIA, et al.

Sci Total Environ, 2017 Dec 01;601-602:556-570.
PMID: 28575833 DOI: 10.1016/j.scitotenv.2017.05.153

This study aims to determine PM2.5concentrations and their composition during haze and non-haze episodes in Kuala Lumpur. In order to investigate the origin of the measured air masses, the Numerical Atmospheric-dispersion Modelling Environment (NAME) and Global Fire Assimilation System (GFAS) were applied. Source apportionment of PM2.5was determined using Positive Matrix Factorization (PMF). The carcinogenic and non-carcinogenic health risks were estimated using the United State Environmental Protection Agency (USEPA) method. PM2.5samples were collected from the centre of the city using a high-volume air sampler (HVS). The results showed that the mean PM2.5concentrations collected during pre-haze, haze and post-haze periods were 24.5±12.0μgm-3, 72.3±38.0μgm-3and 14.3±3.58μgm-3, respectively. The highest concentration of PM2.5during haze episode was five times higher than World Health Organisation (WHO) guidelines. Inorganic compositions of PM2.5, including trace elements and water soluble ions were determined using inductively coupled plasma-mass spectrometry (ICP-MS) and ion chromatography (IC), respectively. The major trace elements identified were K, Al, Ca, Mg and Fe which accounted for approximately 93%, 91% and 92% of the overall metals' portions recorded during pre-haze, haze and post-haze periods, respectively. For water-soluble ions, secondary inorganic aerosols (SO42-, NO3-and NH4+) contributed around 12%, 43% and 16% of the overall PM2.5mass during pre-haze, haze and post-haze periods, respectively. During haze periods, the predominant source identified using PMF was secondary inorganic aerosol (SIA) and biomass burning where the NAME simulations indicate the importance of fires in Sumatra, Indonesia. The main source during pre-haze and post-haze were mix SIA and road dust as well as mineral dust, respectively. The highest non-carcinogenic health risk during haze episode was estimated among the infant group (HI=1.06) while the highest carcinogenic health risk was estimated among the adult group (2.27×10-5).
Fulltext An IoMT-Enabled Smart Healthcare Model to Monitor Elderly People Using Machine Learning Technique

Khan MF, Ghazal TM, Said RA, Fatima A, Abbas S, Khan MA, et al.

Comput Intell Neurosci, 2021;2021:2487759.
PMID: 34868288 DOI: 10.1155/2021/2487759

The Internet of Medical Things (IoMT) enables digital devices to gather, infer, and broadcast health data via the cloud platform. The phenomenal growth of the IoMT is fueled by many factors, including the widespread and growing availability of wearables and the ever-decreasing cost of sensor-based technology. The cost of related healthcare will rise as the global population of elderly people grows in parallel with an overall life expectancy that demands affordable healthcare services, solutions, and developments. IoMT may bring revolution in the medical sciences in terms of the quality of healthcare of elderly people while entangled with machine learning (ML) algorithms. The effectiveness of the smart healthcare (SHC) model to monitor elderly people was observed by performing tests on IoMT datasets. For evaluation, the precision, recall, fscore, accuracy, and ROC values are computed. The authors also compare the results of the SHC model with different conventional popular ML techniques, e.g., support vector machine (SVM), K-nearest neighbor (KNN), and decision tree (DT), to analyze the effectiveness of the result.
Local and transboundary factors' impacts on trace gases and aerosol during haze episode in 2015 El Niño in Malaysia

Samsuddin NAC, Khan MF, Maulud KNA, Hamid AH, Munna FT, Rahim MAA, et al.

Sci Total Environ, 2018 Jul 15;630:1502-1514.
PMID: 29554768 DOI: 10.1016/j.scitotenv.2018.02.289

Southeast Asian haze is a semi-natural phenomenon that chokes the region each year during the dry monsoon season. Smoke-haze episodes caused by the vegetation and peat fires in Indonesia severely affected large parts of Malaysia during the 2015 El Niño phenomenon. This study aimed to evaluate the factors that influenced the concentrations of aerosol and trace gases during the 2015 haze and non-haze period on a semi-urban site in the southern part of Malaysian peninsula that facing Sumatra (Muar, Site A), and on an urban site near to Kuala Lumpur, influenced by the city centre (Cheras, Site B). Local land use data and the cluster of air mass weighted backward trajectory were used to identify the potential factors from local sources and the transboundary region, respectively. The annual median concentrations of PM10 for semi-urban and urban sites were 45.0μg/m3 and 47.0μg/m3, respectively for the study period (Jan-Dec 2015) from the hourly observation dataset. The highest PM10 concentrations during the haze were 358μg/m3 and 415μg/m3 for the two sites, respectively, representing absolutely unhealthy air. However, the trace gases were within the safe threshold. The average concentrations of PM10 and carbon monoxide were two fold higher during the haze than the non-haze episodes on both sites. Nitrogen dioxide was more influenced by haze compared with sulphur dioxide and ozone. The results of the land use change suggest that the local factor can also partially affect the air pollution on the urban area (Site B) but more visible in 2015. The results of the backward trajectory and the wildfire radiative power showed that the smoke-haze episodes that affected Malaysia in 2015 were mainly initiated in the Indonesian Sumatra and Kalimantan regions. This study provides a very useful information towards the impacted region during El Niño haze episode.
Surfactants in the sea surface microlayer, subsurface water and fine marine aerosols in different background coastal areas

Shaharom S, Latif MT, Khan MF, Yusof SNM, Sulong NA, Wahid NBA, et al.

Environ Sci Pollut Res Int, 2018 Sep;25(27):27074-27089.
PMID: 30019134 DOI: 10.1007/s11356-018-2745-0

This study aims to determine the concentrations of surfactants in the surface microlayer (SML), subsurface water (SSW) and fine mode aerosol (diameter size
The presence of polycyclic aromatic hydrocarbons (PAHs) in air particles and estimation of the respiratory deposition flux

Najurudeen NANB, Khan MF, Suradi H, Mim UA, Raim INJ, Rashid SB, et al.

Sci Total Environ, 2023 Mar 29;878:163129.
PMID: 37001671 DOI: 10.1016/j.scitotenv.2023.163129

Polycyclic aromatic hydrocarbons (PAHs) in the atmospheric particles constitute a topic of growing health concern. This study aims to calculate PAH concentrations, identify the source, assess the health risk from exposure to carcinogenic PAHs, and the respiratory deposition flux. PM10 and PM2.5 were collected in September 2019 in the urban, semi-urban, and semi-urban-industrial areas of Kuala Lumpur, Batu Pahat, and Bukit Rambai, respectively. A total of 18 PAHs from PM10 and 17 PAHs from PM2.5 were extracted using dichloromethane and determined using gas chromatography coupled with a flame ionization detector (GC-FID). The health risk assessment (HRA) calculated included B[a]P equivalent (B[a]Peq), lifetime lung cancer risk (LLCR), incremental lifetime cancer risk (ILCR), and respiratory deposition dose (RDD). The results show PAHs in PM10 recorded in Kuala Lumpur (DBKL), Batu Pahat (UTHM), and Bukit Rambai are 9.91, 8.45, and 9.57 ng/m3, respectively. The average PAHs in PM2.5 at the three sampling sites are 11.65, 9.68, and 9.37 ng/m3, respectively. The major source of PAHs obtained from the DRs indicates pyrogenic activities for both particle sizes. For PM10, the total B[a]Peq in DBKL, UTHM, and Bukit Rambai were 1.97, 1.82, and 2.32 ng/m3, respectively. For PM2.5 samples, the total B[a]Peq in DBKL, UTHM, and Bukit Rambai were 2.80, 2.33, and 2.57 ng/m3, respectively. The LLCR and ILCR show low to moderate risk for all age groups. The RDD of adults and adolescents is highest in both PM10 and PM2.5, followed by children, toddlers, and infants. Overall, we perceive that adults and adolescents living in the urban area of Kuala Lumpur are at the highest risk for respiratory health problems because of prolonged exposure to PAHs in PM10 and PM2.5, followed by children, toddlers, and infants.
Fulltext Role of neurotoxicants in the pathogenesis of Alzheimer's disease: a mechanistic insight

Nisa FY, Rahman MA, Hossen MA, Khan MF, Khan MAN, Majid M, et al.

Ann Med, 2021 Dec;53(1):1476-1501.
PMID: 34433343 DOI: 10.1080/07853890.2021.1966088

Alzheimer's disease (AD) is the most conspicuous chronic neurodegenerative syndrome, which has become a significant challenge for the global healthcare system. Multiple studies have corroborated a clear association of neurotoxicants with AD pathogenicity, such as Amyloid beta (Aβ) proteins and neurofibrillary tangles (NFTs), signalling pathway modifications, cellular stress, cognitive dysfunctions, neuronal apoptosis, neuroinflammation, epigenetic modification, and so on. This review, therefore, aimed to address several essential mechanisms and signalling cascades, including Wnt (wingless and int.) signalling pathway, autophagy, mammalian target of rapamycin (mTOR), protein kinase C (PKC) signalling cascades, cellular redox status, energy metabolism, glutamatergic neurotransmissions, immune cell stimulations (e.g. microglia, astrocytes) as well as an amyloid precursor protein (APP), presenilin-1 (PSEN1), presenilin-2 (PSEN2) and other AD-related gene expressions that have been pretentious and modulated by the various neurotoxicants. This review concluded that neurotoxicants play a momentous role in developing AD through modulating various signalling cascades. Nevertheless, comprehension of this risk agent-induced neurotoxicity is far too little. More in-depth epidemiological and systematic investigations are needed to understand the potential mechanisms better to address these neurotoxicants and improve approaches to their risk exposure that aid in AD pathogenesis.Key messagesInevitable cascade mechanisms of how Alzheimer's Disease-related (AD-related) gene expressions are modulated by neurotoxicants have been discussed.Involvement of the neurotoxicants-induced pathways caused an extended risk of AD is explicited.Integration of cell culture, animals and population-based analysis on the clinical severity of AD is addressed.
Distribution, sources and potential health risks of polycyclic aromatic hydrocarbons (PAHs) in PM2.5 collected during different monsoon seasons and haze episode in Kuala Lumpur

Sulong NA, Latif MT, Sahani M, Khan MF, Fadzil MF, Tahir NM, et al.

Chemosphere, 2019 Mar;219:1-14.
PMID: 30528968 DOI: 10.1016/j.chemosphere.2018.11.195

This study aimed to determine the distribution and potential health risks of polycyclic aromatic hydrocarbons (PAHs) in PM2.5 collected in Kuala Lumpur during different monsoon seasons. The potential sources of PM2.5 were investigated using 16 priority PAHs with additional of biomass tracers namely levoglucosan (LV), mannosan (MN) and galactosan (GL). This study also investigated the cytotoxic potential of the extracted PAHs towards V79-4 cells. A high-volume air sampler (HVS) was used to collect PM2.5 samples for 24 h. PAHs were extracted using dichloromethane (DCM) while biomass tracers were extracted by a mixture of DCM/methanol (3:1) before analysis with gas chromatography-mass spectrometry (GC-MS). The cytotoxicity of the PAHs extract was determined by assessing the cell viability through the reduction of tetrazolium salts (MTT). The results showed that the total mean ± SD concentrations of PAHs during the southwest (SW) and northeast (NE) monsoons were 2.51 ± 0.93 ng m-3 and 1.37 ± 0.09 ng m-3, respectively. Positive matrix factorization (PMF) using PAH and biomass tracer concentrations suggested four potential sources of PM2.5; gasoline emissions (29.1%), natural gas and coal burning (28.3%), biomass burning (22.3%), and diesel and heavy oil combustion (20.3%). Health risk assessment showed insignificant incremental lifetime cancer risk (ILCR) of 2.40E-07 for 70 years of exposure. MTT assay suggested that PAHs extracts collected during SW monsoon have cytotoxic effect towards V79-4 cell at the concentrations of 25 μg mL-1, 50 μg mL-1, 100 μg mL-1 whereas non-cytotoxic effect was observed on the PAHs sample collected during NE monsoon.
Effects of drying methods on oxidative stability of roselle seed oil (Hibiscus Sabdariffa): an optimization approach

Jahurul MHA, Shian OK, Sharifudin MS, Hasmadi M, Lee JS, Mansoor AH, et al.

J Food Sci Technol, 2021 Mar;58(3):902-910.
PMID: 33678873 DOI: 10.1007/s13197-020-04604-1

The objective of this study was to optimize the extraction of oil from pre-dried roselle seeds using response surface methodology (RSM). We also determined the oxidative stability of oil extracted from oven and freeze-dried roselle seed in terms of iodine value (IV), free fatty acid (FFA) value, peroxide value (PV), P-anisidine and total oxidation values (TOTOX value). The RSM was designated based on the central composite design with the usage of three optimum parameters ranged from 8 to 16 g of sample weight, 250-350 mL of solvent volume, and 6-8 h of extraction time. The highest oil yielded from roselle seed using the optimization process was 22.11% with the parameters at sample weight of 14.4 g, solvent volume of 329.70 mL, and extraction time of 7.6 h. Besides, the oil extracted from the oven dried roselle seed had the values of 89.04, 2.11, 4.13, 3.76 and 12.03 for IV, FFA, PV, P-anisidine, and TOTOX values, respectively. While for the oil extracted from freeze-dried roselle seed showed IV of 90.31, FFA of 1.64, PV of 2.47, P-anisidine value of 3.48, and TOTOX value of 8.42. PV and TOTOX values showed significant differences whereas; IV, FFA, and P-anisidine values showed no significant differences between the oven and freeze-dried roselle seed oils.

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