Displaying publications 1 - 20 of 373 in total

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  1. Zou JJ, Dai C, Hu J, Tong WK, Gao MT, Zhang Y, et al.
    Sci Total Environ, 2024 Apr 20;922:171201.
    PMID: 38417506 DOI: 10.1016/j.scitotenv.2024.171201
    Mycelial pellets formed by Penicillium thomii ZJJ were applied as efficient biosorbents for the removal of polycyclic aromatic hydrocarbons (PAHs), which are a type of ubiquitous harmful hydrophobic pollutants. The live mycelial pellets were able to remove 93.48 % of pyrene at a concentration of 100 mg/L within 48 h, demonstrating a maximum adsorption capacity of 285.63 mg/g. Meanwhile, the heat-killed one also achieved a removal rate of 65.01 %. Among the six typical PAHs (pyrene, phenanthrene, fluorene, anthracene, fluoranthene, benzo[a]pyrene), the mycelial pellets preferentially adsorbed the high molecular weight PAHs, which also have higher toxicity, resulting in higher removal efficiency. The experimental results showed that the biosorption of mycelial pellets was mainly a spontaneous physical adsorption process that occurred as a monolayer on a homogeneous surface, with mass transfer being the key rate-limiting step. The main adsorption sites on the surface of mycelia were carboxyl and N-containing groups. Extracellular polymeric substances (EPS) produced by mycelial pellets could enhance adsorption, and its coupling with dead mycelia could achieve basically the same removal effect to that of living one. It can be concluded that biosorption by mycelial pellets occurred due to the influence of electrostatic and hydrophobic interactions, consisting of five steps. Furthermore, the potential applicability of mycelial pellets has been investigated considering diverse factors. The mycelia showed high environmental tolerance, which could effectively remove pyrene across a wide range of pH and salt concentration. And pellets diameters and humic acid concentration had a significant effect on microbial adsorption effect. Based on a cost-effectiveness analysis, mycelium pellets were found to be a low-cost adsorbent. The research outcomes facilitate a thorough comprehension of the adsorption process of pyrene by mycelial pellets and their relevant applications, proposing a cost-effective method without potential environmental issues (heat-killed mycelial pellets plus EPS) to removal PAHs.
  2. Zieritz A, Lopes-Lima M, Bogan AE, Sousa R, Walton S, Rahim KA, et al.
    Sci Total Environ, 2016 Nov 15;571:1069-78.
    PMID: 27473771 DOI: 10.1016/j.scitotenv.2016.07.098
    Freshwater mussels (Bivalvia, Unionida) fulfil important ecosystem functions and are one of the most threatened freshwater taxa globally. Knowledge of freshwater mussel diversity, distribution and ecology in Peninsular Malaysia is extremely poor, and the conservation status of half of the species presumed to occur in the region has yet to be assessed. We conducted the first comprehensive assessment of Peninsular Malaysia's freshwater mussels based on species presence/absence and environmental data collected from 155 sites spanning all major river catchments and diverse habitat types. Through an integrative morphological-molecular approach we recognised nine native and one widespread non-native species, i.e. Sinanodonta woodiana. Two species, i.e. Pilsbryoconcha compressa and Pseudodon cambodjensis, had not been previously recorded from Malaysia, which is likely a result of morphological misidentifications of historical records. Due to their restriction to single river catchments and declining distributions, Hyriopsis bialata, possibly endemic to Peninsular Malaysia, Ensidens ingallsianus, possibly already extinct in the peninsula, and Rectidens sumatrensis, particularly require conservation attention. Equally, the Pahang, the Perak and the north-western river catchments are of particular conservation value due to the presence of a globally unique freshwater mussel fauna. Statistical relationships of 15 water quality parameters and mussel presence/absence identified acidification and nutrient pollution (eutrophication) as the most important anthropogenic factors threatening freshwater mussel diversity in Peninsular Malaysia. These factors can be linked to atmospheric pollution, deforestation, oil-palm plantations and a lack of functioning waste water treatment, and could be mitigated by establishing riparian buffers and improving waste water treatment for rivers running through agricultural and residential land.
  3. Zhu J, Lee WH, Yip KC, Wu Z, Wu J, Leaw CP, et al.
    Sci Total Environ, 2023 May 10;872:162236.
    PMID: 36791857 DOI: 10.1016/j.scitotenv.2023.162236
    The dinoflagellates Gambierdiscus and Fukuyoa can produce Ciguatoxins (CTXs) and Maitotoxins (MTXs) that lead to ciguatera poisoning (CP). The CP hotspots, however, do not directly relate to the occurrence of the ciguatoxic Gambierdiscus and Fukuyoa. Species-wide investigations often showed no association between CTX level and the molecular identity of the dinoflagellates. In the Pacific region, Kiribati is known as a CP hotspot, while Malaysia has only three CP outbreaks reported thus far. Although ciguatoxic strains of Gambierdiscus were isolated from both Kiribati and Malaysia, no solid evidence on the contribution of ciguatoxic strains to the incidence of CP outbreak was recorded. The present study aims to investigate the regional differences in CP risks through region-specific toxicological assessment of Gambierdiscus and Fukuyoa. A total of 19 strains of Gambierdiscus and a strain of Fukuyoa were analyzed by cytotoxicity assay of the neuro-2a cell line, hemolytic assay of fish erythrocytes, and high-resolution mass spectrometry. Gambierdiscus from both Kiribati and Malaysia showed detectable ciguatoxicity; however, the Kiribati strains were more hemolytic. Putative 44-methylgambierone was identified as part of the contributors to the hemolytic activity, and other unknown hydrophilic toxins produced can be potentially linked to higher CP incidence in Kiribati.
  4. Zhu J, Cai Y, Wakisaka M, Yang Z, Yin Y, Fang W, et al.
    Sci Total Environ, 2023 Oct 20;896:165200.
    PMID: 37400020 DOI: 10.1016/j.scitotenv.2023.165200
    Microalgae have been recognized as emerging cell factories due to the high value-added bio-products. However, the balance between algal growth and the accumulation of metabolites is always the main contradiction in algal biomass production. Hence, the security and effectiveness of regulating microalgal growth and metabolism simultaneously have drawn substantial attention. Since the correspondence between microalgal growth and reactive oxygen species (ROS) level has been confirmed, improving its growth under oxidative stress and promoting biomass accumulation under non-oxidative stress by exogenous mitigators is feasible. This paper first introduced ROS generation in microalgae and described the effects of different abiotic stresses on the physiological and biochemical status of microalgae from these aspects associated with growth, cell morphology and structure, and antioxidant system. Secondly, the role of exogenous mitigators with different mechanisms in alleviating abiotic stress was concluded. Finally, the possibility of exogenous antioxidants regulating microalgal growth and improving the accumulation of specific products under non-stress conditions was discussed.
  5. Zhu C, Zhou W, Han M, Yang Y, Li Y, Jiang Q, et al.
    Sci Total Environ, 2023 Sep 15;891:164460.
    PMID: 37247739 DOI: 10.1016/j.scitotenv.2023.164460
    Microplastics and nanoplastics (MPs and NPs) are abundant, persistent, and widespread environmental pollutants that are of increasing concern as they pose a serious threat to ecosystems and aquatic species. Identifying the ecological effects of NPs pollution requires understanding the effects of changing nanoplastics concentrations in aquatic organisms. Monopterus albus were orally fed three different concentrations of 100 nm polystyrene nanoplastics (PS-NPs): 0.05 %, 0.5 %, and 1 % of the feed for 28 days. Nanoplastics significantly activated the PPAR signaling pathway, Acyl-CoA oxidase 1 (ACOX1), carnitine palmitoyltransferase 1a (CPT1A), angiopoietin-like 4 (ANGPTL4), and phosphoenolpyruvate carboxykinase (PCK) at the mRNA level, resulting in disturbed lipid metabolism. Glutathione peroxidase (GSH-px) activity, catalase (CAT) activity, and malondialdehyde (MDA) were significantly elevated in the high nanoplastics-feeding exposure group, leading to oxidative stress in the liver. Overexpression of the cytokines genes Interleukin 1 (IL1B) and Interleukin-8 (IL8), Tumor necrosis factor alpha (TNF-α), activation of MAPK signaling pathway, and increased gene expression of c-Jun amino-terminal kinases (JNK) and p38 indicate that exposure to NPs may lead to hepatopancreas apoptosis through oxidative stress and inflammation. In summary, dietary PS-NPs exposure alters hepatic glycolipid metabolism, triggering inflammatory responses and apoptosis in M. albus. The results of this study provide valuable ecotoxicological data for a better understanding of the biological fate and effects of nanoplastics in M. albus.
  6. Zhou XY, Zheng B, Khu ST
    Sci Total Environ, 2019 May 15;665:774-784.
    PMID: 30790750 DOI: 10.1016/j.scitotenv.2019.02.146
    The concept of "carrying capacity" has been widely used in various disciplines in reference to human-environment sustainability. No unified cognition exists regarding carrying capacity limits for humans. As a typical type of carrying capacity, the water environment carrying capacity (WECC) has been researched for human-water environment sustainability. However, most recent research has focused on the assessment of the water environment carrying capacity of a certain region or river basin. The detailed resilience potential of human-water environment systems that could improve the local water environment carrying capacity has not been systematically exploited. The key concerns of the existence of water environment carrying capacity limits and the exact value have not been addressed. This study first distinguished the characteristics of related concepts, such as carrying capacity, planetary boundaries, resilience, limitations, thresholds and tipping points. An analytical framework was then established to exploit the resilience potential from the four dimensions of "scale, structure, pattern and network". The economy scale with full use of the resilience potential is 11,511,880 M yuan under the current technology and development status, which is nearly 37 times that of the current scale of the economy. The analytical framework confirms that the limit on the water environment carrying capacity is a dynamic value, which could be changed from the four dimensions. The socioeconomic scale that the local water environment can support would be nearly unlimited in some extreme ideal situation. The results would provide some enlightenment on the carrying capacity and other similar marked concepts of theoretical research and provide support for human-environment sustainability.
  7. Zhou J, Wu C, Yeh PJ, Ju J, Zhong L, Wang S, et al.
    Sci Total Environ, 2023 Sep 01;889:164274.
    PMID: 37209749 DOI: 10.1016/j.scitotenv.2023.164274
    The successive flood-heat extreme (SFHE) event, which threatens the securities of human health, economy, and building environment, has attracted extensive research attention recently. However, the potential changes in SFHE characteristics and the global population exposure to SFHE under anthropogenic warming remain unclear. Here, we present a global-scale evaluation of the projected changes and uncertainties in SFHE characteristics (frequency, intensity, duration, land exposure) and population exposure under the Representative Concentration Pathway (RCP) 2.6 and 6.0 scenarios, based on the multi-model ensembles (five global water models forced by four global climate models) within the Inter-Sectoral Impact Model Intercomparison Project 2b framework. The results reveal that, relative to the 1970-1999 baseline period, the SFHE frequency is projected to increase nearly globally by the end of this century, especially in the Qinghai-Tibet Plateau (>20 events/30-year) and the tropical regions (e.g., northern South America, central Africa, and southeastern Asia, >15 events/30-year). The projected higher SFHE frequency is generally accompanied by a larger model uncertainty. By the end of this century, the SFHE land exposure is expected to increase by 12 % (20 %) under RCP2.6 (RCP6.0), and the intervals between flood and heatwave in SFHE tend to decrease by up to 3 days under both RCPs, implying the more intermittent SFHE occurrence under future warming. The SFHE events will lead to the higher population exposure in the Indian Peninsula and central Africa (<10 million person-days) and eastern Asia (<5 million person-days) due to the higher population density and the longer SFHE duration. Partial correlation analysis indicates that the contribution of flood to the SFHE frequency is greater than that of heatwave for most global regions, but the SFHE frequency is dominated by the heatwave in northern North America and northern Asia.
  8. Zhou F, Cui J, Zhou J, Yang J, Li Y, Leng Q, et al.
    Sci Total Environ, 2018 Aug 15;633:776-784.
    PMID: 29602116 DOI: 10.1016/j.scitotenv.2018.03.217
    Atmospheric deposition nitrogen (ADN) increases the N content in soil and subsequently impacts microbial activity of soil. However, the effects of ADN on paddy soil microbial activity have not been well characterized. In this study, we studied how red paddy soil microbial activity responses to different contents of ADN through a 10-months ADN simulation on well managed pot experiments. Results showed that all tested contents of ADN fluxes (27, 55, and 82kgNha-1 when its ratio of NH4+/NO3--N (RN) was 2:1) enhanced the soil enzyme activity and microbial biomass carbon and nitrogen and 27kgNha-1 ADN had maximum effects while comparing with the fertilizer treatment. Generally, increasing of both ADN flux and RN (1:2, 1:1 and 2:1 with the ADN flux of 55kgNha-1) had similar reduced effects on microbial activity. Furthermore, both ADN flux and RN significantly reduced soil bacterial alpha diversity (p<0.05) and altered bacterial community structure (e.g., the relative abundances of genera Dyella and Rhodoblastus affiliated to Proteobacteria increased). Redundancy analysis demonstrated that ADN flux and RN were the main drivers in shaping paddy soil bacteria community. Overall, the results have indicated that increasing ADN flux and ammonium reduced soil microbial activity and changed the soil bacterial community. The finding highlights how paddy soil microbial community response to ADN and provides information for N management in paddy soil.
  9. Zheng Y, Ooi MCG, Juneng L, Wee HB, Latif MT, Nadzir MSM, et al.
    Sci Total Environ, 2023 Nov 25;901:166430.
    PMID: 37607626 DOI: 10.1016/j.scitotenv.2023.166430
    Climate change is thought to influence the composition of atmospheric air, but little is known about the direct relationship between these variables, especially in a hot tropical climate like that of Malaysia. This work summarizes and analyzes the climate state and air quality of Peninsular Malaysia based on selected ground-based observations of the temperature, precipitation, relative humidity, wind speed, wind direction and concentrations of PM10, O3, CO, NO2, and SO2 over the last 20 years (2000-2019). The relationship between the climate state and air quality is analyzed using the Pearson correlation and canonical correlation analysis (CCA) methods is employed to predict the degree of change in the future air quality under different warming scenarios. It is found that the Peninsular Malaysia mainly experienced strong precipitation in the central and mountainous regions, while air pollutants are primarily concentrated in densely populated areas. Throughout the period of study (interannual, monthly, and diurnal time series analyses), Peninsular Malaysia became warmer and drier, with a significant increase in temperature (+4.2 %), decrease in the relative humidity (-4.5 %), and greater fluctuation in precipitation amount. The pollution conditions have worsened; there has been an increase in the PM10 (+16.4 %), O3 (+39.5 %), and NO2 (+2.1 %) concentration over the last 20 years. However, the amount of SO2 (-53.6 %) and CO (-20.6 %) decreased significantly. The analysis of the monthly variation shows a strong bimodality of the PM10 and O3 concentrations that corresponds to the monsoon transition. Intensive diurnal fluctuations and correlations are observed for all the variables in this study. According to the CCA, the air quality factors are strongly correlated with meteorological factors; in particular, the CO, O3, and PM10 concentrations interact strongly with the air temperature. These findings show that the future air quality in Peninsular Malaysia has high possibility to deteriorate under warming condition.
  10. Zhao X, Taheripour F, Malina R, Staples MD, Tyner WE
    Sci Total Environ, 2021 Jul 20;779:146238.
    PMID: 33744564 DOI: 10.1016/j.scitotenv.2021.146238
    Sustainable aviation fuels (SAFs) are expected to play an essential role in achieving the aviation industries' goal of carbon-neutral growth. However, producing biomass-based SAFs may induce changes in global land use and the associated carbon stock. The induced land use change (ILUC) emissions, as a part of the full life-cycle emissions for SAF pathways, will affect whether and to what extent SAFs reduce emissions compared with petroleum-based jet fuels. Here, we estimate the ILUC emission intensity for seventeen SAF pathways considered by the International Civil Aviation Organization (ICAO), covering five ASTM-certified technologies, nine biomass-based feedstocks, and four geographical regions. We introduce the SAF pathways into a well-established computable general equilibrium (CGE) model, GTAP-BIO, and its coupled emission accounting model, AEZ-EF, to study economy-wide implications of SAF production and estimate ILUC emissions intensity for each pathway. The estimated SAF ILUC emission intensities, using a 25-year amortization period, range from -58.5 g CO2e MJ-1 for the USA miscanthus alcohol (isobutanol)-to-jet (ATJ) pathway to 34.6 g CO2e MJ-1 for the Malaysia & Indonesia palm oil Hydrotreated Esters of Fatty Acids (HEFA) pathway. Notably, the vegetable oil pathways tend to have higher ILUC emission intensities due to their linkage to palm expansion and peatland oxidation in Southeast Asia. The cellulosic pathways studied provide negative ILUC emissions, mainly driven by the high carbon sequestrations in crop biomass and soil. Using the core life-cycle emissions established by ICAO, we show that fifteen of the assessed pathways have a lower full life-cycle emission intensity than petroleum-based jet fuels (89 g CO2e MJ-1), offering promising options to reduce aviation emissions.
  11. Zhao J, Yu L, Newbold T, Shen X, Liu X, Hua F, et al.
    Sci Total Environ, 2024 Apr 20;922:171296.
    PMID: 38423324 DOI: 10.1016/j.scitotenv.2024.171296
    Largely driven by agricultural pressures, biodiversity has experienced great changes globally. Exploring biodiversity responses to agricultural practices associated with agricultural intensification can benefit biodiversity conservation in agricultural landscapes. However, the effects of agricultural practices may also extend to natural habitats. Moreover, agricultural impacts may also vary with geographical region. We analyze biodiversity responses to landscape cropland coverage, cropping frequency, fertiliser and yield, among different land-use types and across geographical regions. We find that species richness and total abundance generally respond negatively to increased landscape cropland coverage. Biodiversity reductions in human land-use types (pasture, plantation forest and cropland) were stronger in tropical than non-tropical regions, which was also true for biodiversity reductions with increasing yield in both human and natural land-use types. Our results underline substantial biodiversity responses to agricultural practices not only in cropland but also in natural habitats, highlighting the fact that biodiversity conservation demands a greater focus on optimizing agricultural management at the landscape scale.
  12. Zhang X, Chan NW, Pan B, Ge X, Yang H
    Sci Total Environ, 2021 Nov 10;794:148388.
    PMID: 34217078 DOI: 10.1016/j.scitotenv.2021.148388
    The SAR has the ability of all-weather and all-time data acquisition, it can penetrate the cloud and is not affected by extreme weather conditions, and the acquired images have better contrast and rich texture information. This paper aims to investigate the use of an object-oriented classification approach for flood information monitoring in floodplains using backscattering coefficients and interferometric coherence of Sentinel-1 data under time series. Firstly, the backscattering characteristics and interference coherence variation characteristics of SAR time series are used to analyze whether the flood disaster information can be accurately reflected and provide the basis for selecting input classification characteristics of subsequent SAR images. Subsequently, the contribution rate index of the RF model is used to calculate the importance of each index in time series to convert the selected large number of classification features into low dimensional feature space to improve the classification accuracy and reduce the data redundancy. Finally, the SAR image features in each period after multi-scale segmentation and feature selection are jointly used as the input features of RF classification to extract and segment the water in the study area to monitor floods' spatial distribution and dynamic characteristics. The results showed that the various attributes of backscatter coefficients and interferometric coherence under time series could accurately correspond with the actual flood risk, and the combined use of backscattering coefficient and interferometric coherence for flood extraction can significantly improve the accuracy of flood information extraction. Overall, the object-based random forest method using the backscattering coefficient and interference coherence of Sentinel-1 time series for flood extraction advances our understanding of flooding's temporal and spatial dynamics, essential for the timely adoption of adaptation and mitigation strategies for loss reduction.
  13. Zhang MW, Yeoh FY, Du Y, Lin KA
    Sci Total Environ, 2019 Aug 15;678:466-475.
    PMID: 31077925 DOI: 10.1016/j.scitotenv.2019.04.295
    As methyltheobromine (MTB) has been increasingly detected in wastewater, it would be necessary to develop more intensive and effective approaches to remove MTB. As Co species immobilized on carbonaceous materials appears as a promising catalyst, doping carbon with nitrogen has been also validated to significantly enhance catalytic activities for Oxone activation. Therefore, it is desired to develop a composite of immobilizing Co species on N-doped carbonaceous supports for activating Oxone to degrade MTB. Unfortunately, very few studies have demonstrated such composites for activating Oxone to degrade MTB as this type of composites are conventionally prepared via complex procedures. Alternatively, this study aims to develop such a composite conveniently by using a cobaltic coordination polymer (CP) as a precursor. Specifically Co2+ and 4,4-bipyridine (BIPY) are selected for formulating a special one-dimensional CP, which is then carbonized to convert Co to Co nanoparticles (NPs) and transform BIPY to carbon nitride (CN) matrices. Because of 1-D coordinated structure of CoBIPY, the resulting magnetic Co NPs are well-distributed and protected within CN to form a magnetic Co-embedded carbon nitride composite (MCoCN). In comparison to pristine CN and Co3O4, MCoCN exhibits much higher catalytic activities to activate Oxone for degrading MTB completely within 7 min. MCoCN also shows a much lower activation energy of 24.6 kJ/mol than other reported catalysts for activating Oxone to degrade MTB. The findings of this study validate that the 1-D coordination polymer of CoBIPY is a useful precursor to prepare MCoCN for effectively activating Oxone to degrade MTB.
  14. Zakaria NA, Azamathulla HM, Chang CK, Ghani AA
    Sci Total Environ, 2010 Oct 1;408(21):5078-85.
    PMID: 20708217 DOI: 10.1016/j.scitotenv.2010.07.048
    This paper presents Gene-Expression Programming (GEP), which is an extension to the genetic programming (GP) approach to predict the total bed material load for three Malaysian rivers. The GEP is employed without any restriction to an extensive database compiled from measurements in the Muda, Langat, and Kurau rivers. The GEP approach demonstrated a superior performance compared to other traditional sediment load methods. The coefficient of determination, R(2) (=0.97) and the mean square error, MSE (=0.057) of the GEP method are higher than those of the traditional method. The performance of the GEP method demonstrates its predictive capability and the possibility of the generalization of the model to nonlinear problems for river engineering applications.
  15. Zainun MY, Simarani K
    Sci Total Environ, 2018 Mar;616-617:269-278.
    PMID: 29117585 DOI: 10.1016/j.scitotenv.2017.10.266
    The municipal landfill is an example of human-made environment that harbours some complex diversity of microorganism communities. To evaluate this complexity, the structures of bacterial communities in active (operational) and closed (non-operational) landfills in Malaysia were analysed with culture independent metagenomics approaches. Several points of soil samples were collected from 0 to 20cm depth and were subjected to physicochemical test, such as temperature, pH, and moisture content. In addition, the heavy metal contamination was determined by using ICPMS. The bacterial enumeration was examined on nutrient agar (NA) plates aerobically at 30°C. The soil DNA was extracted, purified and amplified prior to sequence the 16S rRNA gene for statistical and bioinformatics analyses. As a result, the average of bacteria for the closed landfill was higher compared to that for the active landfill at 9.16×107 and 1.50×107, respectively. The higher bacterial OTUs sequenced was also recorded in closed landfills compared to active landfill i.e. 6625 and 4552 OTUs respectively. The data from both landfills showed that the predominant phyla belonged to Proteobacteria (55.7%). On average, Bacteroidetes was the second highest phylum followed by Firmicutes for the active landfill. While the phyla for communities in closed landfill were dominated by phyla from Acidobacteria and Actinobacteria. There was also Euryarchaeota (Archaea) which became a minor phylum that was detected in active landfill, but almost completely absent in closed landfill. As such, the composition of bacterial communities suggests some variances between the bacterial communities found in active and closed landfills. Thus, this study offers new clues pertaining to bacterial diversity pattern between the varied types of landfills studied.
  16. Zain SMSM, Latif MT, Baharudin NH, Anual ZF, Mohd Hanif N, Khan MF
    Sci Total Environ, 2021 Aug 20;783:146929.
    PMID: 34088111 DOI: 10.1016/j.scitotenv.2021.146929
    Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are toxic compounds derived from anthropogenic sources that stay in the environment for long periods. Ambient air has become the most important pathway for the transfer of PCDDs/PCDFs from emission sources to the environment. This review intends to summarise the information available on atmospheric PCDDs/PCDFs in the countries of Southeast Asia to provide a detailed description of the trends in PCDDs/PCDFs emissions, key sources, and levels in urban, rural, and industrial air as reported in peer-reviewed literature since 2000 and by the United Nations Environment Programme. As the largest country in Southeast Asia, Indonesia is the major PCDDs/PCDFs emitter, accounting for 72.81% of the total release of PCDDs/PCDFs in the air from all available inventories in this region, while Brunei Darussalam is the lowest emitter, contributing to less than 0.02%. Open burning processes have become the largest source of ambient PCDDs/PCDFs in the region (69.62%), followed by waste incineration (10.69%), and ferrous and non-ferrous metal production (8.78%). PCDDs/PCDFs levels in rural areas ranged between 10 and 38 fg TEQ m-3; however, where open burning waste has occurred, the levels rose to 12-29 times higher. In urban areas, ambient levels were 15 times greater than in rural areas, varying from 23 to 565 fg TEQ m-3. Atmospheric concentrations near industrial palm oil and waste incinerator sites were between 64 and 1530 fg TEQ m-3. The non-cancer risk of ambient exposure to PCDDs/PCDFs through inhalation is low among populations near facilities emitting PCDDs/PCDFs. The lack of local technical capacity, the high economic costs, and the lack of established human resource capacities have been the major challenges in conducting ambient PCDDs/PCDFs studies in most countries in the region.
  17. Zaied BK, Nasrullah M, Siddique MNI, Zularisam AW, Singh L, Krishnan S
    Sci Total Environ, 2020 Mar 01;706:136095.
    PMID: 31862587 DOI: 10.1016/j.scitotenv.2019.136095
    Lack of sufficient nitrogenous substrate and buffering potential have been acknowledged as impediments to the treatment of palm oil mill effluent through co-digestion processes. In this study, ammonium bicarbonate was used to provide the nitrogenous substrate and buffering potential. To regulate the impact of ammonium bicarbonate toxicity on the anaerobic co-digestion system, dosages from 0 to 40 mg/L were supplemented. The biogas yield was used to indicate the effects of NH4+ toxicity. In a solar-assisted bioreactor, solar radiation was first collected by a solar panel and converted into electricity, which was then used to heat a mixture of palm oil mill effluent and cattle manure to maintain the reactor in the mesophilic temperature range. This co-digestion operation was performed semi-continuously and was analyzed at a 50:50 mixing ratio of palm oil mill effluent and cattle manure. The results indicate that the additional dosing of ammonium bicarbonate can significantly enhance biogas production. Maximum cumulative biogas and methane productions of 2034.00 mL and 1430.51 mL, respectively, were obtained with the optimum addition of 10 mg/L ammonium bicarbonate; these values are 29.80% and 42.30% higher, respectively, than that obtained in the control co-digestion operation without addition of ammonium bicarbonate. Utilization of a mathematical equation (G = Gmk/t) to describe a kinetic analysis of the biogas yield also indicated that the optimum ammonium bicarbonate dose was 10 mg/L. The results of this study suggest that supplementation with ammonium bicarbonate doses of up to 40 mg/L can be used to provide nitrogenous substrates and buffering potential in anaerobic co-digestion processes. The determination of the optimal dose provides an alternative and efficient option for enhanced biogas production, which will have obvious economic advantages for feasible industrial applications.
  18. Zaied BK, Rashid M, Nasrullah M, Zularisam AW, Pant D, Singh L
    Sci Total Environ, 2020 Jul 15;726:138095.
    PMID: 32481207 DOI: 10.1016/j.scitotenv.2020.138095
    The pharmaceuticals are emergent contaminants, which can create potential threats for human health and the environment. All the pharmaceutical contaminants are becoming enormous in the environment as conventional wastewater treatment cannot be effectively implemented due to toxic and intractable action of pharmaceuticals. For this reason, the existence of pharmaceutical contaminants has brought great awareness, causing significant concern on their transformation, occurrence, risk, and fate in the environments. Electrocoagulation (EC) treatment process is effectively applied for the removal of contaminants, radionuclides, pesticides, and also harmful microorganisms. During the EC process, an electric current is employed directly, and both electrodes are dissoluted partially in the reactor under the special conditions. This electrode dissolution produces the increased concentration of cation, which is finally precipitated as hydroxides and oxides. Different anode materials usage like aluminum, stainless steel, iron, etc. are found more effective in EC operation for efficient removal of pharmaceutical contaminants. Due to the simple procedure and less costly material, EC method is extensively recognized for pharmaceutical wastewater treatment over further conventional treatment methods. The EC process has more usefulness to destabilize the pharmaceutical contaminants with the neutralization of charge and after that coagulating those contaminants to produce flocs. Thus, the review places particular emphasis on the application of EC process to remove pharmaceutical contaminants. First, the operational parameters influencing EC efficiency with the electroanalysis techniques are described. Second, in this review emerging challenges, current developments and techno-economic concerns of EC are highlighted. Finally, future recommendations and prospective on EC are envisioned.
  19. Zabed H, Suely A, Faruq G, Sahu JN
    Sci Total Environ, 2014 Feb 15;472:363-9.
    PMID: 24295752 DOI: 10.1016/j.scitotenv.2013.11.051
    A sacred ritual well with continuously discharging of methane gas through its water body was studied for physicochemical and microbiological quality in three seasons and during ritual mass bathing. Most of the physicochemical parameters showed significant seasonal variations (P<0.05) and a sharp fluctuation during mass bathing. Dissolved oxygen (DO) was found negatively correlated with temperature (r=-0.384, P<0.05), biochemical oxygen demand (BOD) (r=-0.58, P<0.001) and ammonia (r=-0.738, P<0.001), while BOD showed positive correlation with chemical oxygen demand (COD) (r=0.762, P<0.001) and ammonia (r=0.83, P<0.001). Simple regression analysis also yielded significant linear relationship in DO vs. temperature (r(2)=0.147, P<0.05), DO vs. ammonia (r(2)=0.544, P<0.001) and BOD vs. DO (r(2)=0.336, P<0.001). A total of eight microbial indicators were studied and found that all of them increased unusually during mass bathing comparing with their respective seasonal values. Total coliforms (TC) were found positively correlated with fecal coliforms (FC) (r=0.971), FC with Escherichia coli (EC) (r=0.952), EC with intestinal enterococci (IE) (r=0.921), fecal streptococci (FS) with IE (r=0.953) and Staphylococcus aureus (SA) with Pseudomonas aeruginosa (PA) (r=0.946), which were significant at P<0.001. Some regression models showed significant linear relationship at P<0.001 with r(2) value of 0.943 for FC vs. TC, 0.907 for EC vs. FC, 0.869 for FS vs. FC, 0.848 for IE vs. EC and 0.909 for IE vs. FS. The overall results found in this study revealed that well water is suitable for bathing purpose but the religious activity considerably worsen its quality.
  20. Yuan C, Wu F, Wu Q, Fornara DA, Heděnec P, Peng Y, et al.
    Sci Total Environ, 2023 Jun 25;879:163059.
    PMID: 36963687 DOI: 10.1016/j.scitotenv.2023.163059
    Vegetation restoration is a widely used, effective, and sustainable method to improve soil quality in post-mining lands. Here we aimed to assess global patterns and driving factors of potential vegetation restoration effects on soil carbon, nutrients, and enzymatic activities. We synthesized 4838 paired observations extracted from 175 publications to evaluate the effects that vegetation restoration might have on the concentrations of soil carbon, nitrogen, and phosphorus, as well as enzymatic activities. We found that (1) vegetation restoration had consistent positive effects on the concentrations of soil organic carbon, total nitrogen, available nitrogen, ammonia, nitrate, total phosphorus, and available phosphorus on average by 85.4, 70.3, 75.7, 54.6, 58.6, 34.7, and 60.4 %, respectively. Restoration also increased the activities of catalase, alkaline phosphatase, sucrase, and urease by 63.3, 104.8, 125.5, and 124.6 %, respectively; (2) restoration effects did not vary among different vegetation types (i.e., grass, tree, shrub and their combinations) or leaf type (broadleaved, coniferous, and mixed), but were affected by mine type; and (3) latitude, climate, vegetation species richness, restoration year, and initial soil properties are important moderator variables, but their effects varied among different soil variables. Our global scale study shows how vegetation restoration can improve soil quality in post-mining lands by increasing soil carbon, nutrients, and enzymatic activities. This information is crucial to better understand the role of vegetation cover in promoting the ecological restoration of degraded mining lands.
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