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Geo-accumulation index and contamination factors of heavy metals (Zn and Pb) in urban river sediment

Haris H, Looi LJ, Aris AZ, Mokhtar NF, Ayob NAA, Yusoff FM, et al.

Environ Geochem Health, 2017 Dec;39(6):1259-1271.
PMID: 28484873 DOI: 10.1007/s10653-017-9971-0

The aim of the present study was to appraise the levels of heavy metal contamination (Zn and Pb) in sediment of the Langat River (Selangor, Malaysia). Samples were collected randomly from 15 sampling stations located along the Langat River. The parameters measured were pH, redox potential, salinity, electrical conductivity, loss of ignition, cation exchanges capacity (Na, Mg, Ca, K), and metal ions (Zn and Pb). The geo-accumulation index (I geo) and contamination factor (C f) were applied to determine and classify the magnitude of heavy metal pollution in this urban river sediment. Results revealed that the I geo of Pb indicated unpolluted to moderately polluted sediment at most of the sampling stations, whereas Zn was considered to be within background concentration. The I geo results were refined by the C f values, which showed Pb with very high C f at 12 stations. Zinc, on the other hand, had low to moderate C f values. These findings indicated that the sediment of the Langat River is severely polluted with Pb. The Zn concentration at most sampling points was well below most sediment quality guidelines. However, 40% of the sampling points were found to have a Pb concentration higher than the consensus-based probable effect concentration of 128 mg/kg (concentrations above this value are likely to cause harmful effects). This result not only highlights the severity of Pb pollution in the sediment of the Langat River, but also the potential risk it poses to the environment.

Matched MeSH terms: Urbanization*
Assessing drivers of benthic macroinvertebrate community structure in African highland streams: An exploration using multivariate analysis

Dalu T, Wasserman RJ, Tonkin JD, Alexander ME, Dalu MTB, Motitsoe SN, et al.

Sci Total Environ, 2017 Dec 01;601-602:1340-1348.
PMID: 28605853 DOI: 10.1016/j.scitotenv.2017.06.023

Understanding the drivers of community structure is fundamental for adequately managing ecosystems under global change. Here we used a large dataset of eighty-four headwater stream sites in three catchments in the Eastern Highlands of Zimbabwe, which represent a variety of abiotic conditions and levels of impairment, to examine the drivers of benthic macroinvertebrate community structure. We focused our assessment on macroinvertebrate family level community composition and functional feeding group classifications. Taxonomic richness was weakly positively correlated with ammonium, phosphates and pH, and weakly negatively correlated with detrital cover and dissolved oxygen. Measured abiotic variables, however, had limited influence on both macroinvertebrate diversity and functional feeding group structure, with the exception of ammonium, channel width and phosphates. This reflected the fact that many macroinvertebrate families and functional feeding guilds were well represented across a broad range of habitats. Predatory macroinvertebrates were relatively abundant, with collector-filterers having the lowest relative abundances. The findings of the study suggest that for certain ecological questions, a more detailed taxonomic resolution may be required to adequately understand the ecology of aquatic macroinvertebrates within river systems. We further recommend management and conservation initiatives on the Save River system, which showed significant impact from catchment developmental pressures, such as urbanisation, agriculture and illegal mining.

Matched MeSH terms: Urbanization
Fulltext Municipal solid waste characteristics in Taman Universiti, Skudai, Johore, Malaysia

Edward Hingha Foday Jr, Nurul As'shikin Ramli, Hairu Nabilah Ismail, Nulhazwany Abdul Malik, Hazlami Fikri Basri, Fatihah Syahirah Abdul Aziz, et al.

Journal of Advanced Research Design, 2017;38(1):13-20.
MyJurnal

Malaysia is one of the developing countries that are facing an increase population
with an increasing and significant generation of waste. Environmental problems may
arise when the solid waste management is improper. The rate of generation is
increasing and the composition is also changing as the nation becomes more
urbanized and industrialized. The objective of this study is to present the data of
municipal solid waste (MSW) generated in Taman Universiti, Skudai, Johor Bahru,
Malaysia. The composition of MSW was studied by segregating it into different
components such as food waste, paper, glass, plastics, metal and tin aluminums. It
was observed that Taman Universiti area produced around 40% plastics waste which
was the highest component compared to other waste, followed by food waste and
papers with 38.2% and 21% respectively. Meanwhile, food waste was recorded the
highest moisture content with 38.2% while glass had the lowest moisture content
with 0.4%. The reliable estimate of MSW generated is important for proper waste
management planning. These data could enhance in implementation of waste
management system in that area.

Matched MeSH terms: Urbanization
Fulltext Mathematical modelling of dengue pattern in Penang, Malaysia

Norzaida Abas, Rafidah Mohd Shamsuddin, Noor Shazwani Osman, Syafrina Abd. Halim

Journal of Advanced Research Design, 2017;37(1):9-15.
MyJurnal

Dengue fever is an endemic disease in many tropical and subtropical regions. In
Malaysia, it is the leading public health challenge despite the extensive intervention
programs by the related authorities. Distribution of dengue cases in Malaysia varies
according to states and districts where cases are more distinct in urban and suburban
areas. Preparedness strategies of dengue cases could be more successful with some
comprehensive and technical analysis on disease incidences. Hence, the present study
analyses dengue cases using mathematical modelling in the state of Penang, one of the
more urbanised state. In particular, two time series models are fitted to the dengue
data from the region in order to identify the mathematical model that best describe
the data. Results show that both proposed models are able to represent the cases
rather well; however numerical inspection revealed that Double Exponential
Smoothing method is the better choice. Subsequently, the identified model is used to
make forecasting on the number of expected cases. Results show that dengue cases in
Penang are expected to increase gradually.

Matched MeSH terms: Urbanization
Fulltext The association between climatic factors and dengue fever: a study in Subang Jaya and Sepang, Selangor

Nik Syaza Lina Nik Ruzman, Haliza Abdul Rahman

Malaysian Journal of Public Health Medicine, 2017;17 Special(1):140-150.

Dengue fever is one of the most dangerous vector-borne diseases. According to the World Health Organization (WHO), dengue fever is a mosquito-borne infection caused by virus serotype DEN-1, DEN-2, DEN-3 and DEN-4. In Malaysia, dengue fever cases are on the rise from 6,000 cases in 1995 to over 40,000 in 2010, and this number is still rising. In 2014, the increase of dengue fever cases was alarming. It was reported that up to the end of the year 2014, there were 108,698 notified cases, indicating an increment of 151% compared to the same period of time in 2013 with only 43,346 reported cases. Selangor was the highest contributor of dengue fever cases in 2014. The objective of this paper is to study the relationship between climatic factors namely temperature, rainfall and humidity to the prevalence of dengue fever in Subang Jaya and Sepang district, Selangor. Data on monthly average temperature, precipitation, relative humidity and dengue fever cases for each month in 2014 and 2013 were collected. Data collection was dealt with a few institutions such as Malaysian Meteorological Department, Subang Jaya and Sepang Municipal Council and health district offices. Data were analysed using SPSS (Statistical Package for the Social Sciences) Version 20. General linear model analysis was used to investigate the relationship between the climatic variables and dengue prevalence. Results and Discussion: Based on the general linear model, rainfall and humidity were found to have significant relationships to monthly dengue fever cases (p= <0.001, p= 0.002). Rainfall was identified as the most significant predictor because rainfall can provide more breeding places for Aedes mosquitoes. As for humidity, higher relative humidity had been associated with increased Aedes aegypti feeding activity, survival and egg development. Temperature was not significantly related to monthly dengue fever cases (p= 0.561) in this study. However, this could be due to the short period of study. Conclusion: Climatic factors play an important role in the prevalence of dengue fever. However, there are many other factors of dengue fever that should be considered such as urbanisation as well as community knowledge, attitude and practice.

Matched MeSH terms: Urbanization
Fulltext Effects of urbanization on host-pathogen interactions, using Yersinia in house sparrows as a model

Rouffaer LO, Strubbe D, Teyssier A, Salleh Hudin N, Van den Abeele AM, Cox I, et al.

PLoS One, 2017;12(12):e0189509.
PMID: 29281672 DOI: 10.1371/journal.pone.0189509

Urbanization strongly affects biodiversity, altering natural communities and often leading to a reduced species richness. Yet, despite its increasingly recognized importance, how urbanization impacts on the health of individual animals, wildlife populations and on disease ecology remains poorly understood. To test whether, and how, urbanization-driven ecosystem alterations influence pathogen dynamics and avian health, we use house sparrows (Passer domesticus) and Yersinia spp. (pathogenic for passerines) as a case study. Sparrows are granivorous urban exploiters, whose western European populations have declined over the past decades, especially in highly urbanized areas. We sampled 329 house sparrows originating from 36 populations along an urbanization gradient across Flanders (Belgium), and used isolation combined with 'matrix-assisted laser desorption ionization- time of flight mass spectrometry' (MALDI-TOF MS) and PCR methods for detecting the presence of different Yersinia species. Yersinia spp. were recovered from 57.43% of the sampled house sparrows, of which 4.06%, 53.30% and 69.54% were identified as Y. pseudotuberculosis, Y. enterocolitica and other Yersinia species, respectively. Presence of Yersinia was related to the degree of urbanization, average daily temperatures and the community of granivorous birds present at sparrow capture locations. Body condition of suburban house sparrows was found to be higher compared to urban and rural house sparrows, but no relationships between sparrows' body condition and presence of Yersinia spp. were found. We conclude that two determinants of pathogen infection dynamics, body condition and pathogen occurrence, vary along an urbanization gradient, potentially mediating the impact of urbanization on avian health.

Matched MeSH terms: Urbanization*
River sediment metal and nutrient variations along an urban-agriculture gradient in an arid austral landscape: implications for environmental health

Dalu T, Wasserman RJ, Wu Q, Froneman WP, Weyl OLF

Environ Sci Pollut Res Int, 2018 Jan;25(3):2842-2852.
PMID: 29143261 DOI: 10.1007/s11356-017-0728-1

The effect of metals on environmental health is well documented and monitoring these and other pollutants is considered an important part of environmental management. Developing countries are yet to fully appreciate the direct impacts of pollution on aquatic ecosystems and as such, information on pollution dynamics is scant. Here, we assessed the temporal and spatial dynamics of stream sediment metal and nutrient concentrations using contaminant indices (e.g. enrichment factors, pollution load and toxic risk indices) in an arid temperate environment over the wet and dry seasons. The mean sediment nutrient, organic matter and metal concentration were highest during the dry season, with high values being observed for the urban environment. Sediment contaminant assessment scores indicated that during the wet season, the sediment quality was acceptable, but not so during the dry season. The dry season had low to moderate levels of enrichment for metals B, Cu, Cr, Fe, Mg, K and Zn. Overall, applying the sediment pollution load index highlighted poor quality river sediment along the length of the river. Toxic risk index indicated that most sites posed no toxic risk. The results of this study highlighted that river discharge plays a major role in structuring temporal differences in sediment quality. It was also evident that infrastructure degradation was likely contributing to the observed state of the river quality. The study contributes to our understanding of pollution dynamics in arid temperate landscapes where vast temporal differences in base flow characterise the riverscape. Such information is further useful for contrasting sediment pollution dynamics in aquatic environments with other climatic regions.

Matched MeSH terms: Urbanization
Heavy metal pollution in immobile and mobile components of lentic ecosystems-a review

Meena RAA, Sathishkumar P, Ameen F, Yusoff ARM, Gu FL

Environ Sci Pollut Res Int, 2018 Feb;25(5):4134-4148.
PMID: 29247419 DOI: 10.1007/s11356-017-0966-2

With growing population and urbanization, there is an increasing exploitation of natural resources, and this often results to environmental pollution. In this review, the levels of heavy metal in lentic compartments (water, sediment, fishes, and aquatic plants) over the past two decades (1997-2017) have been summarized to evaluate the current pollution status of this ecosystem. In all the compartments, the heavy metals dominated are zinc followed by iron. The major reason could be area mineralogy and lithogenic sources. Enormous quantity of metals like iron in estuarine sediment is a very natural incident due to the permanently reducing condition of organic substances. Contamination of cadmium, lead, and chromium was closely associated with anthropogenic origin. In addition, surrounding land use and atmospheric deposition could have been responsible for substantial pollution. The accumulation of heavy metals in fishes and aquatic plants is the result of time-dependent deposition in lentic ecosystems. Moreover, various potential risk assessment methods for heavy metals were discussed. This review concludes that natural phenomena dominate the accumulation of essential heavy metals in lentic ecosystems compared to anthropogenic sources. Amongst other recent reviews on heavy metals from other parts of the world, the present review is executed in such a way that it explains the presence of heavy metals not only in water environment, but also in the whole of the lentic system comprising sediment, fishes, and aquatic plants.

Matched MeSH terms: Urbanization
Fulltext The Tsinghua-Lancet Commission on Healthy Cities in China: unlocking the power of cities for a healthy China

Yang J, Siri JG, Remais JV, Cheng Q, Zhang H, Chan KKY, et al.

Lancet, 2018 05 26;391(10135):2140-2184.
PMID: 29678340 DOI: 10.1016/S0140-6736(18)30486-0
Matched MeSH terms: Urbanization*
Fulltext Do wild-caught urban house sparrows show desensitized stress responses to a novel stressor?

Salleh Hudin N, Teyssier A, Aerts J, Fairhurst GD, Strubbe D, White J, et al.

Biol Open, 2018 Jun 15;7(6).
PMID: 29632231 DOI: 10.1242/bio.031849

While urbanization exposes individuals to novel challenges, urban areas may also constitute stable environments in which seasonal fluctuations are buffered. Baseline and stress-induced plasma corticosterone (cort) levels are often found to be similar in urban and rural populations. Here we aimed to disentangle two possible mechanisms underlying such pattern: (i) urban environments are no more stressful or urban birds have a better ability to habituate to stressors; or (ii) urban birds developed desensitized stress responses. We exposed wild-caught urban and rural house sparrows (Passer domesticus) to combined captivity and diet treatments (urban versus rural diet) and measured corticosterone levels both in natural tail feathers and in regrown homologous ones (cortf). Urban and rural house sparrows showed similar cortf levels in the wild and in response to novel stressors caused by the experiment, supporting the growing notion that urban environments are no more stressful during the non-breeding season than are rural ones. Still, juveniles and males originating from urban populations showed the highest cortf levels in regrown feathers. We did not find evidence that cortf was consistent within individuals across moults. Our study stresses the need for incorporating both intrinsic and environmental factors for the interpretation of variation in cortf between populations.

Matched MeSH terms: Urbanization
Influence of foreign direct investment on indicators of environmental degradation

Solarin SA, Al-Mulali U

Environ Sci Pollut Res Int, 2018 Jun 21.
PMID: 29931634 DOI: 10.1007/s11356-018-2562-5

This study aims to contribute to the existing literature by looking at the influence of foreign direct investment on carbon dioxide emissions, carbon footprint, and ecological footprint. In order to realize the aim of this study, we have utilized the augmented mean group estimator, which is supported by common correlated effect mean group estimator in the analysis for 20 countries. The panel results reveal that foreign direct investment has no effect on environmental degradation indicators. The panel results further reveal that gross domestic product, energy consumption, and urbanization are the main contributors to environmental degradation. The results at country level show that foreign direct investment and urbanization increase pollution in the developing countries while they mitigate pollution in the developed countries. Moreover, gross domestic product and energy consumption increase pollution for both developed and developing countries, which includes China and the USA. The negative impact of foreign direct investment on environmental degradation in the developed countries can be explained on the basis that these countries have strong environmental regulations, which makes it almost impossible for dirty foreign industries to invest therein. From the output of this research, several policy recommendations are enumerated for the investigated countries.

Matched MeSH terms: Urbanization
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.

Matched MeSH terms: Urbanization
Fulltext Nipah virus epidemic in southern India and emphasizing "One Health" approach to ensure global health security

Chattu VK, Kumar R, Kumary S, Kajal F, David JK

J Family Med Prim Care, 2018 8 10;7(2):275-283.
PMID: 30090764 DOI: 10.4103/jfmpc.jfmpc_137_18

Nipah virus (NiV) encephalitis first reported in "Sungai Nipah" in Malaysia in 1999 has emerged as a global public health threat in the Southeast Asia region. From 1998 to 2018, more than 630 cases of NiV human infections were reported. NiV is transmitted by zoonotic (from bats to humans, or from bats to pigs, and then to humans) as well as human-to-human routes. Deforestation and urbanization of some areas have contributed to greater overlap between human and bat habitats resulting in NiV outbreaks. Common symptoms of NiV infection in humans are similar to that of influenza such as fever and muscle pain and in some cases, the inflammation of the brain occurs leading to encephalitis. The recent epidemic in May 2018 in Kerala for the first time has killed over 17 people in 7 days with high case fatality and highlighted the importance of One Health approach. The diagnosis is often not suspected at the time of presentation and creates challenges in outbreak detection, timely control measures, and outbreak response activities. Currently, there are no drugs or vaccines specific for NiV infection although this is a priority disease on the World Health Organization's agenda. Antivirals (Ribavirin, HR2-based fusion inhibitor), biologicals (convalescent plasma, monoclonal antibodies), immunomodulators, and intensive supportive care are the mainstay to treat severe respiratory and neurologic complications. There is a great need for strengthening animal health surveillance system, using a One Health approach, to detect new cases and provide early warning for veterinary and human public health authorities.

Matched MeSH terms: Urbanization
Characterization and Risk Analysis of Metals Associated with Urban Dust in Rawang (Malaysia)

Praveena SM

Arch Environ Contam Toxicol, 2018 Oct;75(3):415-423.
PMID: 29802419 DOI: 10.1007/s00244-018-0537-7

This study was designed to determine the particle size distribution and develop road dust index combining source and transport factors involving road dust for dust pollution quantification in Rawang. Principal component analysis (PCA) was applied to identify possible sources of potentially toxic elements and spot major pollution areas in Rawang. The health risks (carcinogenic and noncarcinogenic) to adults and children were assessed using the hazard index and total lifetime cancer Risk, respectively. A total of 75 road dust samples were collected and particle sizes (1000, 500, 250, 160, 125 and 63 µm) were determined. Concentrations of potentially toxic elements (Cu, Cd, Co, Cr, Pb, Ni, Zn and As) in particle size of 63 µm were analyzed. The results demonstrated that the highest grain size of 250 µm has contributed almost more than 25% of atmospheric particulate pollution. The highest potentially toxic element concentration was Pb (593.3 mg/kg), whereas the lowest was Co (5.6 mg/kg). Road dust index output indicated that pollution risk fell into moderate levels in eastern and northern areas of Rawang. Similarly, PCA results revealed that potentially toxic elements (Cu, Cd, Pb, Zn, Ni and Cr) were linked with anthropogenic sources (urbanization process, industrial and commercial growth, urban traffic congestion) in northern and southern parts of Rawang. Cobalt and As concentrations were explained mainly from natural sources. Noncarcinogenic risk by hazard index value more than 1.0 was indicated for adults and children. Similarly, carcinogenic risk by total lifetime cancer risk value also showed carcinogenic risks among adults and children.

Matched MeSH terms: Urbanization
Determinants of pollution and the role of the military sector: evidence from a maximum likelihood approach with two structural breaks in the USA

Solarin SA, Al-Mulali U, Ozturk I

Environ Sci Pollut Res Int, 2018 Nov;25(31):30949-30961.
PMID: 30182312 DOI: 10.1007/s11356-018-3060-5

We investigate the role of military expenditure on emission in USA during the period 1960-2015. To achieve the objectives of this study, two measures of military expenditure are utilised, while several timeseries models are constructed with the gross domestic product (GDP) per capita, population, energy consumption per capita, non-renewable energy consumption per capita, renewable energy consumption per capita, urbanisation, trade openness and financial development serving as additional determinants of air pollution. We also use ecological indicator as an alternative measure of pollution. Moreover, different timeseries methods are utilised including a likelihood-based approach with two structural breaks. The output of this research concluded that all the variables are cointegrated. It is found that military expenditure has mixed impact on CO2 emissions. Real GDP per capita, energy consumption per capita, non-renewable energy consumption per capita, population and urbanisation increase CO2 emissions per capita in the long-run, while renewable energy consumption, financial development and trade openness reduce it. There is also evidence for the mixed role of military expenditure, when ecological footprint is utilised as the environmental degradation index. From the output of this research, few policy recommendations are offered for the examined country.

Matched MeSH terms: Urbanization
Assessment of pollution and improvement measure of water quality parameters using scenarios modeling for sungai Selangor basin

Md. Sadek Uddin Chowdhury, Faridah Othman, Wan Zurina Wan Jaafar, Nuzaima Che Mood, Md. Ibrahim Adham

Sains Malaysiana, 2018;47:457-469.

Sungai Selangor is very important from the viewpoint of water supply and multipurpose water use in Malaysia. The
water quality of this river is degrading due to point and non-point sources of pollution. This study, focus on the water
quality assessment and simulation the effect of the pollution sources from urbanization to the Sungai Selangor basin.
Water quality Index (WQI) is used to define the status of river water quality and the QUAL2K was used as a simulation
model. Water quality parameters DO, BOD and NH3
-N have been chosen for modeling. In addition, five different model
scenarios were simulated to observe the impacts of pollution sources on the Sungai Selangor water quality. WQI results
showed that most of the stations in this river basin recorded water inferior to Class III. The water quality model presented
different scenarios for changes of Sungai Selangor water quality. Simulation results for different scenarios showed
that reduced levels of BOD and NH3
-N at 51.10% and 66.18%, respectively, can be obtained if Scenario-5 is employed.
The river water quality issue in the Rawang sub- basin within the study area is considered crucial to create significant
improvement within the sub basin and in the downstream area of Sungai Selangor basin.

Matched MeSH terms: Urbanization
Fulltext Green wall for retention of stormwater

Mah, D.Y.S., Lau, J.T.

Pertanika Journal of Science & Technology, 2018;26(1):283-298.
MyJurnal

Urbanisation increases the level of imperviousness in a catchment, and more runoff is converted from rainfall in urban areas. To mitigate this adverse situation, dispensed green infrastructure presents the best solution for delivering results in reducing stormwater impact. Green roofs and rain gardens are extensively studied and widely available in the literature, but this is not the case for green walls, which more often than not, are treated as ornaments. Thus, this study developed a computer-aided stormwater model that incorporates a green wall to investigate its effectiveness as an urban drainage system. The effectiveness of employing a green wall as a stormwater component is tested using USEPA SWMM 5.1 and the embedded bioretention cell interface. Four simulation models according to different conditions and precipitation input are tested, compared and discussed. The conditions include investigation of different soil types, average recurrence interval (ARI) and storm duration with design and observed rainfall. The results reveal that synthesis precipitation data, used in Scenario 1, 2 and 3, decreased runoff by more than half, at 55% on condition of one-year ARI and 5 minutes of storm duration. Meanwhile, Scenario 4 also shows a repetition of runoff reduction by half after the integration of the green wall using the observed rainfall data. Thus, it is verified that a green wall can be effectively used as an urban drainage system in reducing surface runoff.

Matched MeSH terms: Urbanization
Fulltext Longitudinal changes in suspended sediment loading and sediment budget of Merbok river catchment, Kedah, Malaysia

Ibrahim, M.N., Ismail, W.R., Najib, S.A.M.

Pertanika Journal of Science & Technology, 2018;26(4):1899-1991.
MyJurnal

Merbok river catchment situated in the Kedah State receives its input from Bongkok River
and Puntar River flowing down and joining Lalang River to flow down to the Merbok
Estuary. The Merbok catchment (440 km2) is experiencing several degrees of complex
land uses activities that poses some impact on the suspended sediment production of
the Merbok river. A study was conducted to investigate the suspended sediment loading
of rivers draining the Merbok catchment from January to December 2013. Suspended
sediment budget of the Merbok catchment were estimated. The river suspended sediment
concentrations (SSC) and suspended sediment (SS) load increased during wet season
compared to dry season. The SS loads increases from upper catchment to river mouth. The
sediment loadings were divided into three segments- the upstream, middle segment and
lower segment. The SS loads increased from 10 t yr-1 in the upper part of Bongkok river
to 3336 t yr-1 in upper segment. The sediment loading then increase to 4299 t yr-1 in the
middle segment of the catchment (at Bongkok 4), and then exiting the Merbok Estuary, as
the lower segment, with a total amount of sediment output estimated at 7156 t yr-1. From this
total sediment output, most of the sediment
source came from the tributaries; the
Bongkok River at B3 (3337 t yr-1), Puntar
River (2924 t yr-1) and Lalang River (1370
t yr-1), which were much higher than its
proportion in terms of its length and drainage
area. As a conclusion, the inconsistence in
SSC in the river were influenced by the
various anthropogenic activities (especially
agriculture and urbanization activities) in the catchment area which necessitate future land use and sediment control to avoid sediment
and possible nutrient loading into the estuary.

Matched MeSH terms: Urbanization
Population Density and Risk of Inflammatory Bowel Disease: A Prospective Population-Based Study in 13 Countries or Regions in Asia-Pacific

Ng SC, Kaplan GG, Tang W, Banerjee R, Adigopula B, Underwood FE, et al.

Am J Gastroenterol, 2019 01;114(1):107-115.
PMID: 30177785 DOI: 10.1038/s41395-018-0233-2

INTRODUCTION: Living in an urban environment may increase the risk of developing inflammatory bowel disease (IBD). It is unclear if this observation is seen globally. We conducted a population-based study to assess the relationship between urbanization and incidence of IBD in the Asia-Pacific region.
METHODS: Newly diagnosed IBD cases between 2011 and 2013 from 13 countries or regions in Asia-Pacific were included. Incidence was calculated with 95% confidence interval (CI) and pooled using random-effects model. Meta-regression analysis was used to assess incidence rates and their association with population density, latitude, and longitude.
RESULTS: We identified 1175 ulcerative colitis (UC), 656 Crohn's disease (CD), and 37 IBD undetermined (IBD-U). Mean annual IBD incidence per 100 000 was 1.50 (95% CI: 1.43-1.57). India (9.31; 95% CI: 8.38-10.31) and China (3.64; 95% CI, 2.97-4.42) had the highest IBD incidence in Asia. Incidence of overall IBD (incidence rate ratio [IRR]: 2.19; 95% CI: 1.01-4.76]) and CD (IRR: 3.28; 95% CI: 1.83-9.12) was higher across 19 areas of Asia with a higher population density. In China, incidence of IBD (IRR: 2.37; 95% CI: 1.10-5.16) and UC (IRR: 2.63; 95% CI: 1.2-5.8) was positively associated with gross domestic product. A south-to-north disease gradient (IRR: 0.94; 95% CI: 0.91-0.98) was observed for IBD incidence and a west-to-east gradient (IRR: 1.14; 95% CI: 1.05-1.24) was observed for CD incidence in China. This study received IRB approval.
CONCLUSIONS: Regions in Asia with a high population density had a higher CD and UC incidence. Coastal areas within China had higher IBD incidence. With increasing urbanization and a shift from rural areas to cities, disease incidence may continue to climb in Asia.

Matched MeSH terms: Urbanization
Fulltext Association of rodent-borne Leptospira spp. with urban environments in Malaysian Borneo

Blasdell KR, Morand S, Perera D, Firth C

PLoS Negl Trop Dis, 2019 02;13(2):e0007141.
PMID: 30811387 DOI: 10.1371/journal.pntd.0007141

Although leptospirosis is traditionally considered a disease of rural, agricultural and flooded environments, Leptospira spp. are found in a range of habitats and infect numerous host species, with rodents among the most significant reservoirs and vectors. To explore the local ecology of Leptospira spp. in a city experiencing rapid urbanization, we assessed Leptospira prevalence in rodents from three locations in Malaysian Borneo with differing levels of anthropogenic influence: 1) high but stable influence (urban); 2) moderate yet increasing (developing); and 3) low (rural). A total of 116 urban, 122 developing and 78 rural rodents were sampled, with the majority of individuals assigned to either the Rattus rattus lineage R3 (n = 165) or Sundamys muelleri (n = 100). Leptospira spp. DNA was detected in 31.6% of all rodents, with more urban rodents positive (44.8%), than developing (32.0%) or rural rodents (28.1%), and these differences were statistically significant. The majority of positive samples were identified by sequence comparison to belong to known human pathogens L. interrogans (n = 57) and L. borgpetersenii (n = 38). Statistical analyses revealed that both Leptospira species occurred more commonly at sites with higher anthropogenic influence, particularly those with a combination of commercial and residential activity, while L. interrogans infection was also associated with low forest cover, and L. borgpetersenii was more likely to be identified at sites without natural bodies of water. This study suggests that some features associated with urbanization may promote the circulation of Leptospira spp., resulting in a potential public health risk in cities that may be substantially underestimated.

Matched MeSH terms: Urbanization

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