ORCID Profile
0000-0002-2134-3710
Current Organisation
Hong Kong Metropolitan University
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Publisher: Elsevier BV
Date: 04-2009
Publisher: Wiley
Date: 04-2005
Abstract: Contamination of shellfish with paralytic shellfish poisoning toxins (PST) produced by toxic harmful algal blooms (HABs) have been negatively affecting the shellfish and aquaculture industries worldwide. Therefore, accurate and early identification of toxic phytoplankton species is crucial in HABs surveillance programs that allow fish-farmers to take appropriate preventive measures in shellfish harvesting and other aquaculture activities to overcome the negative impacts of HABs on human health. The identification of toxic dinoflagellates present in the water is currently a time-consuming operation since it requires skillful taxonomists and toxicologists equipped with optical and scanning electron microscopes as well as sophisticated equipment, for ex le, high-performance liquid chromotography-fluorescence detection. In this paper, a two-dimensional gel electrophoresis (2-DE)-based proteomic approach was applied to discriminate between toxic and nontoxic strains of Alexandrium minutum. Variation in morphological features between toxic and nontoxic strains was minimal and not significant. Also, variation in 2-DE protein patterns within either toxic or nontoxic strains was low, but pronounced differences were detected between toxic and nontoxic strains. The most notable differences between these strains were several abundant proteins with pIs ranging from 4.8 to 5.3 and apparent molecular masses between 17.5 and 21.5 kDa. Groups of proteins, namely NT1, NT2, NT3, and NT4, were consistently found in all nontoxic strains, while T1 and T2 were prominent in the toxic strains. These specific protein spots characteristic for toxic and nontoxic strains remained clearly distinguishable irrespective of the various growth conditions tested. Therefore, they have the potential to serve as "taxonomic markers" to distinguish toxic and nontoxic strains within A. minutum. Initial studies revealed that the expression pattern of T1 was tightly correlated to toxin biosynthesis in the examined alga and may be used to serve as a potential toxin indicator.
Publisher: Wiley
Date: 12-03-2020
DOI: 10.1111/FAF.12455
Publisher: Wiley
Date: 15-03-2022
DOI: 10.1111/FAF.12653
Abstract: Macroalgae‐dominated reefs are a prominent habitat in tropical seascapes that support a ersity of fishes, including fishery target species. To what extent, then, do macroalgal habitats contribute to small‐scale tropical reef fisheries? To address this question we: (1) Quantified the macroalgae‐associated fish component in catches from 133 small‐scale fisheries, (2) Compared life‐history traits relevant to fishing (e.g. growth, longevity) in macroalgal and coral‐associated fishes, (3) Examined how macroalgae‐associated species can influence catch ersity, trophic level and vulnerability and (4) Explored how tropical fisheries change with the expansion of macroalgal habitats using a case study of fishery‐independent data for Seychelles. Fish that utilised macroalgal habitats comprise 24% of the catch, but very few fished species relied entirely on macroalgal or coral habitats post‐settlement. Macroalgal and coral‐associated fishes had similar life‐history traits, although vulnerability to fishing declined with increasing contribution of macroalgae association to the catch, whilst mean trophic level and ersity peaked when macroalgal‐associated fish accounted for 20%–30% of catches. The Seychelles case study revealed similar total fish biomass on macroalgal and coral reefs, although the biomass of primary target species increased as macroalgae cover expanded. Our findings reinforce that multiple habitat types are needed to support tropical fishery stability and sustainability. Whilst coral habitats have been the focus of tropical fisheries management, we show the potential for macroalgae‐associated fish to support catch size and ersity in ways that reduce vulnerability to overfishing. This is pertinent to seascapes where repeated disturbances are facilitating the replacement of coral reef with macroalgal habitats.
Publisher: Elsevier BV
Date: 2004
DOI: 10.1016/J.ENVPOL.2003.08.007
Abstract: Green lipped mussels, Perna viridis, and blue mussels, Mytilus edulis, were collected from seven locations along the east coast of China in September and October 2001. The mussel tissues were analyzed for metals (Ag, As, Cd, Cr, Ni, Pb, Se, Zn, Cu, Fe and Hg), and trace organic contaminants including organochlorine compounds (OCs), polycyclic aromatic hydrocarbons (PAHs based on 24 in idual PAHs), polychlorinated biphenyls (PCBs) and petroleum hydrocarbons (PHCs). Maximum concentrations of Ag, As, Cd, Cr, Ni, Pb, Se, Zn, Cu, Fe and Hg in the mussel tissues were 0.14, 26.76, 5.31, 15.72, 4.78, 2.93, 7.40, 231.0, 54.17, 1002 and 317.3 microg/g dry weight respectively. Levels of DDTs, PAHs, PCBs and PHCs in the mussel s les were 14-640, 456-3495, 1-13 ng/g and 621-2863 microg/g dry weight, respectively. Results of this study indicated that contaminant levels were, in general, higher or at least comparable to those reported in other local or regional studies. Mussel s les collected in Chongming Dao in Shanghai and Jiao Zhou Wan in Qingdao had significantly higher levels of metal and trace organic contaminants among the seven s ling stations. Examination of the contaminant profiles suggests that PHCs originated from petrogenic sources, while both petrogenic and pyrolytic sources were important for PAHs. The generally high levels of metals and organochlorine compounds are probably the result of increasingly intense industrial activities along the east coast of China. An assessment of potential risks to human health due to consumption of the mussels was undertaken for the metals, PCBs, DDTs and chlordanes, and the results indicated that all metals, except Ni, could pose a health risk to heavy seafood consumers, while Hg appears to be of concern even for low level consumers.
Publisher: Elsevier BV
Date: 2008
DOI: 10.1016/J.MARPOLBUL.2008.03.038
Abstract: Biomarkers are generally applied to detect pollution in environmental monitoring. Such biological responses should accurately reflect the stress over time in a quantitative manner. As such, the initial and maximum responses induced by stress, as well as adaptation and recovery of these biomarkers, need to be fully understood or else erroneous false-negative or false-positive may be arrived. However, most of the biomarker studies only provided information on initially induced responses under different concentrations of toxicants, while biological adaptation and recovery were poorly known. In this study, the time required for induction, adaptation and recovery of lysosomal integrity in green-lipped mussel Perna viridis upon exposure to benzo[a]pyrene was investigated over a period of 62 days. Maximum induction occurred on day 6 when lysosomal integrity was significantly reduced by 51%, and no further change or adaptation was detected thereafter. When mussels were depurated in clean seawater after 18 days of exposure to benzo[a]pyrene, a gradual recovery was observed, with lysosomal integrity returning to its background level and showing a complete recovery after 20 days of depuration. Lysosomal integrity was significantly correlated with the body burden concentrations of benzo[a]pyrene and condition index of the mussels. The relatively fast induction (6 days) and recovery (20 days) without apparent adaptation suggested that lysosomal integrity in P. viridis can serve as a good biomarker in biomonitoring, as its response is not likely to generate both false-negative and false-positive results.
Publisher: Elsevier BV
Date: 08-2004
Publisher: Elsevier BV
Date: 12-2007
DOI: 10.1016/J.TAAP.2007.07.013
Abstract: The H295R cell bioassay was used to evaluate the potential endocrine disrupting effects of 18 of the most commonly used pharmaceuticals in the United States. Exposures for 48 h with single pharmaceuticals and binary mixtures were conducted the expression of five steroidogenic genes, 3betaHSD2, CYP11beta1, CYP11beta2, CYP17 and CYP19, was quantified by Q-RT-PCR. Production of the steroid hormones estradiol (E2), testosterone (T) and progesterone (P) was also evaluated. Antibiotics were shown to modulate gene expression and hormone production. Amoxicillin up-regulated the expression of CYP11beta2 and CYP19 by more than 2-fold and induced estradiol production up to almost 3-fold. Erythromycin significantly increased CYP11beta2 expression and the production of P and E2 by 3.5- and 2.4-fold, respectively, while production of T was significantly decreased. The beta-blocker salbutamol caused the greatest induction of CYP17, more than 13-fold, and significantly decreased E2 production. The binary mixture of cyproterone and salbutamol significantly down-regulated expression of CYP19, while a mixture of ethynylestradiol and trenbolone, increased E2 production 3.7-fold. Estradiol production was significantly affected by changes in concentrations of trenbolone, cyproterone, and ethynylestradiol. Exposures with in idual pharmaceuticals showed the possible secondary effects that drugs may exert on steroid production. Results from binary mixture exposures suggested the possible type of interactions that may occur between drugs and the joint effects product of such interactions. Dose-response results indicated that although two chemicals may share a common mechanism of action the concentration effects observed may be significantly different.
Publisher: Elsevier BV
Date: 12-2002
DOI: 10.1016/S0025-326X(02)00263-1
Abstract: The outer layers of layflat, low density polyethylene plastic tubing (the principal component of semi-permeable membrane devices, SPMDs) were biofouled at a clean site in Hong Kong coastal waters for periods of 1-4 weeks. Following pre-fouling, triolein was added to the SPMDs and, along with control (unfouled) devices, they were exposed to a range of organochlorine pesticides (alpha-HCH, aldrin, p,p'-DDT) and PAHs (anthracene, fluoranthene and benzo(a)pyrene) under laboratory conditions. Results showed that the uptake of contaminants by SPMDs was severely reduced by as much as 50% under fouling conditions in comparison to unfouled controls. The ultimate utility of SPMDs as passive monitors is thus reduced, although alternative measures, such as the use of permeability reference compounds may compensate, and allow for realistic evaluations of dissolved environmental concentrations in aquatic environments. However, due to the complexities involved in such procedures--especially as they need to be conducted on a case-by-case basis-the utility of SPMDs appears to be limited for estimates of bioavailability unless necessary calibrations are undertaken within each environment that the s ler is used.
Publisher: Elsevier BV
Date: 2008
DOI: 10.1016/J.MARPOLBUL.2008.03.012
Abstract: Due to growing concerns regarding persistent organic pollutants (POPs) in the environment, extensive studies and monitoring programs have been carried out in the last two decades to determine their concentrations in water, sediment, and more recently, in biota. An extensive review and analysis of the existing literature shows that whilst the vast majority of these efforts either attempt to compare (a) spatial changes (to identify "hot spots"), or (b) temporal changes to detect deterioration/improvement occurring in the environment, most studies could not provide sufficient statistical power to estimate concentrations of POPs in the environment and detect spatial and temporal changes. Despite various national POPs standards having been established, there has been a surprising paucity of emphasis in establishing accurate threshold concentrations that indicate potential significant threats to ecosystems and public health. Although most monitoring programs attempt to check compliance through reference to certain "environmental quality objectives", it should be pointed out that many of these established standards are typically associated with a large degree of uncertainty and rely on a large number of assumptions, some of which may be arbitrary. Non-compliance should trigger concern, so that the problem can be tracked down and rectified, but non-compliance must not be interpreted in a simplistic and mechanical way. Contaminants occurring in the physical environment may not necessarily be biologically available, and even when they are bioavailable, they may not necessarily elicit adverse biological effects at the in idual or population levels. As such, we here argue that routine monitoring and reporting of abiotic and biotic POPs concentrations could be of limited use, unless such data can be related directly to the assessment of public health and ecological risks. Risk can be inferred from the ratio of predicted environmental concentration (PEC) and the predicted no effect concentration (PNEC). Currently, the paucity of data does not allow accurate estimation of PNEC, and future endeavors should therefore, be devoted to determine the threshold concentrations of POPs that can cause undesirable biological effects on sensitive receivers and important biological components in the receiving environment (e.g. keystone species, populations with high energy flow values, etc.), to enable derivation of PNECs based on solid scientific evidence and reduce uncertainty. Using the threshold body burden of POPs required to elicit damages of lysosomal integrity in the green mussel (Perna virvidis) as an ex le, we illustrate how measurement of POPs in body tissue could be used in predicting environmental risk in a meaningful way.
Publisher: American Chemical Society (ACS)
Date: 29-05-2009
DOI: 10.1021/ES900637A
Abstract: The recent development of a sensitive and accurate analytical method for the analysis of 20 perfluorinated compounds (PFCs), including several short-chain PFCs, has enabled their quantification in tap water collected in China, Japan, India, the United States, and Canada between 2006 and 2008. Of the PFCs measured, PFOS, PFHxS, PFBS, PFPrS, PFEtS, PFOSA, N-EtFOSAA, PFDoDA, PFUnDA, PFDA, PFNA, PFHpA, PFHxA, PFPeA, PFBA, and PFPrA were found at detectable concentrations in the tap water s les. The water s les from Shanghai (China) contained the greatest concentrations of total PFCs (arithmetic mean = 130 ng/L), whereas those from Toyama (Japan) contained only 0.62 ng/L. In addition to PFOS and PFOA, short-chain PFCs such as PFHxS, PFBS, PFHxA, and PFBA were found to be prevalent in drinking water. According to the health-based values (HBVs) and advisory guidelines derived for PFOS, PFOA, PFBA, PFHxS, PFBS, PFHxA, and PFPeA by the U.S.EPA and the Minnesota Department of Health, tap water may not pose an immediate health risk to consumers.
Publisher: Hindawi Limited
Date: 12-1999
Publisher: Elsevier BV
Date: 10-2005
DOI: 10.1016/J.MARPOLBUL.2005.02.040
Abstract: Local marine environments in China's Pearl River Delta (PRD), the most rapidly developing region in one of the world's fastest growing economies, have been experiencing significant environmental stress during the past decades. This investigation was conducted to determine the status and trends of persistence organic pollutants (POPs) such as polycyclic aromatic hydrocarbons (PAHs), petroleum hydrocarbons (PHCs), polychlorinated biphenyls (PCBs), organochlorine (OC) pesticides and dioxin-related compounds in marine sediments collected from sixteen coastal stations in the Pearl River Delta (PRD) in March 2003. Elevated concentrations of PAHs (94-4300 ng/g), PCBs (6.0-290 ng/g), PHCs (14-150 microg/g), and DDTs (1.4-600 ng/g) were detected in sediment s les. In addition, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-like activities in the sediment s les were estimated to range from 0.3 to 440 pg TCDD-EQ/g. Sediments collected from Xiashan contained the greatest concentrations of trace organic contaminations amongst all the s ling stations in the present study. The degree of trace organic contamination was, in general, more severe at stations situated along the west shores of the PRD than their counterparts in the east. A preliminary assessment was performed to examine the probable risks to the marine ecosystem due to POPs. The results showed that OC pesticide contamination in the PRD was particularly serious and might pose a threat to the health of the marine inhabitants.
Publisher: Hindawi Limited
Date: 06-1999
Publisher: Elsevier BV
Date: 02-2010
DOI: 10.1016/J.SCITOTENV.2009.12.044
Abstract: Lysosomal integrity in mussels is widely used as a biomarker in coastal environments to demonstrate exposure to trace organic pollutants. However, few studies have determined the long-term influences of seasonal variations on the bioaccumulation of trace organics and subsequently altered response of lysosomal integrity in mussels. This study aimed to test three null hypotheses that (1) bioaccumulations of total polycyclic aromatic hydrocarbon (SigmaPAH) and (2) total polychlorinated biphenyl (SigmaPCB), and (3) lysosomal integrity as indicated by Neutral Red retention time (NRRT) in haemocytes, in the green-lipped mussel Perna viridis were not seasonally dependent. The tissue concentrations of SigmaPAH and SigmaPCB and haemocytic NRRT were determined in P. viridis in a metropolitan harbour, subtropical Hong Kong during the wet and dry seasons from 2004 to 2007. Additional information on temperature, salinity, dissolved oxygen and total ammonia nitrogen in seawater, and sediment levels of SigmaPAH and SigmaPCB, were extracted from published data and re-analyzed. Our results accepted all null hypotheses, based on the minimal seasonal influences of seawater temperature and salinity on all studied parameters, in which no significant differences between the wet and dry seasons were detected. The seasonal effect was likely outweighed by the greatly improved water quality and pollution abatement noted inside the harbour, with a gradual shift in mussel PAHs from a pyrolytic origin to a petrogenic origin. Spatially, the site east of the harbour was relatively unpolluted. The single use of NRRT in P. viridis explained 25% of the total variation of the integrated pollution patterns in seawater, sediments and mussels. The present study suggested that the dynamic change of trace organics could be reflected by the response on lysosomal integrity in P. viridis, which was recommended as a routine screening biomarker in monitoring of harbour water quality across seasons.
Publisher: Elsevier BV
Date: 05-2006
DOI: 10.1016/J.CHEMOSPHERE.2005.08.013
Abstract: Some endocrine disrupting chemicals (EDCs) in the environment have been shown to exert their biological effects through interference with steroidogenesis. In this study, the potential effects of four selected polychlorinated biphenyl (PCB) congeners (PCB101, PCB110, PCB126 and PCB149) as well as several of their environmentally-relevant methylsulfonyl-(MeSO(2)-) PCB metabolites (3'-MeSO(2)-CB101, 4'-MeSO(2)-CB101, 4'-MeSO(2)-CB110, 3'-MeSO(2)-CB149 and 4'-MeSO(2)-CB149) on adrenocortical steroidogenesis were evaluated by in vitro bioassay based on the human adrenocortical carcinoma H295R cell line. The PCBs included in the study represented different structures and potential mechanisms of action. Cells were exposed for 48 h to 10 microM of each PCB congener in the presence or absence of 20% (w/w) of their corresponding MeSO(2)-PCB metabolite(s). After the chemical treatments, changes in mRNA expression of 11 steroidogenic genes (CYP11A, CYP11B1, CYP11B2, CYP17, CYP19, CYP21, 3beta-HSD1, 3beta-HSD2, 17beta-HSD1, StAR and HMGR) were quantified using molecular beacon-based real-time RT-PCR. Genes coding for enzymes involved in the later or final steps of steroid production (CYP11B1, CYP11B2, CYP19, 3beta-HSD1, 3beta-HSD2 and 17beta-HSD1) were up-regulated to various extents by most PCBs. The greatest transcriptional activations (2.8-29.9-fold) were elicited by PCB110 on CYP11B1, CYP11B2, 3beta-HSD2 and CYP19, and PCB149 on CYP11B1, 3beta-HSD1 and 17beta-HSD1. Increased expression of these steroidogenic genes might ultimately lead to a change in hormonal balance through excessive production of steroid hormones including aldosterone, cortisol and estradiol. In addition, co-treatment with 3'- and 4'-MeSO(2)-PCB149 resulted in a significant decrease in PCB149-induced 3beta-HSD1 and 17beta-HSD1 expression. This result indicates that some PCB congeners and their MeSO(2)-metabolites may affect steroidogenesis via different mechanisms. Overall, these findings suggest that PCBs and PCB metabolites can affect regulation of adrenocortical steroidogenesis.
Publisher: Elsevier BV
Date: 2005
DOI: 10.1016/J.MARPOLBUL.2005.01.008
Abstract: Nodularia spumigena periodically proliferates to cause toxic algal blooms with some aquatic animals enduring and consuming high densities of the blue green algae or toxic lysis. N. spumigena contains toxic compounds such as nodularin and lipopolysaccharides. This current work investigates physiological effects of exposure from bloom conditions of N. spumigena cells and a post-bloom lysis. Biochemical and antioxidative biomarkers were comparatively studied over an acute 3-day exposure. In general, a post-bloom N. spumigena lysis caused opposite physiological responses to bloom densities of N. spumigena. Specifically, increases in glutathione (GSH) and glutathione peroxidase (GPx) and decreases in glutathione S-transferase (GST) were observed from the N. spumigena lysis. In contrast, N. spumigena cell densities decreased GSH and increased GST and lipid peroxidation (LPO) in mussels. Findings also suggest that at different stages of a toxic bloom, exposure may result in toxic stress to specific organs in the mussel.
Publisher: Elsevier BV
Date: 05-1998
Publisher: Elsevier BV
Date: 12-2013
DOI: 10.1016/J.FORSCIINT.2013.09.003
Abstract: The measurement of illicit drug metabolites in raw wastewater is increasingly being adopted as an approach to objectively monitor population-level drug use, and is an effective complement to traditional epidemiological methods. As such, it has been widely applied in western countries. In this study, we utilised this approach to assess drug use patterns over nine days during April 2011 in Hong Kong. Raw wastewater s les were collected from the largest wastewater treatment plant serving a community of approximately 3.5 million people and analysed for excreted drug residues including cocaine, ketamine, meth hetamine, 3,4-methylenedioxymeth hetamine (MDMA) and key metabolites using liquid chromatography coupled with tandem mass spectrometry. The overall drug use pattern determined by wastewater analysis was consistent with that have seen amongst people coming into contact with services in relation to substance use among our target drugs, ketamine (estimated consumption: 1400-1600 mg/day/1000 people) was the predominant drug followed by meth hetamine (180-200 mg/day/1000 people), cocaine (160-180 mg/day/1000 people) and MDMA (not detected). The levels of these drugs were relatively steady throughout the monitoring period. Analysing s les at higher temporal resolution provided data on diurnal variations of drug residue loads. Elevated ratios of cocaine to benzoylecgonine were identified unexpectedly in three s les during the evening and night, providing evidence for potential dumping events of cocaine. This study provides the first application of wastewater analysis to quantitatively evaluate daily drug use in an Asian metropolitan community. Our data reinforces the benefit of wastewater monitoring to health and law enforcement authorities for strategic planning and evaluation of drug intervention strategies.
Publisher: Elsevier BV
Date: 12-2006
DOI: 10.1016/J.MARPOLBUL.2006.06.009
Abstract: The marine ecosystem of the Pearl River Delta, located on the southern coast of China, has been heavily exploited following the rapid economic growth that has occurred since the 1980s. This investigation aimed to elucidate trace organic contamination in marine biota inhabiting the Pearl River Delta area. Biota s les, including green-lipped mussels (Perna viridis), oysters (Crassostrea rivularis) and shrimp (Penaeus orientalis) were s led from 16 stations fringing the Estuary. Elevated concentrations (on a dry weight basis) of polycyclic aromatic hydrocarbons (27.8-1041.0 ng/g), petroleum hydrocarbons (1.7-2345.4 microg/g), polychlorinated biphenyls (2.1-108.8 ng/g), DDTs (1.9-79.0 ng/g), and hexachlorocyclohexanes (n.d.-38.4 ng/g) were recorded. A human health risk assessment was conducted to estimate the risk to local residents associated with the consumption of biota collected from the Pearl River Estuary. The results indicated that PCBs were at levels that may cause deleterious health effects in populations that consume large amounts of seafood. However, it would be instructive to establish health criteria for trace organic contaminants that are specific to the local populations, in order to derive a more accurate and relevant health risk assessment.
Publisher: Elsevier BV
Date: 2003
DOI: 10.1016/S0043-1354(02)00294-4
Abstract: Eggs of two Ardeid species, the Little Egret (Egretta garzetta) and the Black-crowned Night Heron (Nycticorax nycticorax), were collected from two egretries located in the New Territories of Hong Kong with one located near the internationally acclaimed wetland reserve, the Mai Po Marshes, and the other in a remote site (A Chau). The eggs were analysed for organochlorine (OC) compounds including the DDTs, PCBs, hexachlorocyclohexanes (HCHs) and the chlordanes (CHLs). All of the OCs under investigation were detected in the eggs of both species with significantly higher levels in the Little Egret (DDTs, 560-2200 PCBs, 270-1700 CHLs, 81-470 ng g(-1) wet weight) than the Night Heron (DDTs, 210-1200 PCBs, 85-600 CHLs 59-75 ng g(-1) wet weight). The DDTs consisted mainly of DDE with levels ranging from 85% to 95% of the total. The HCHs were at about the same levels in both species (8.4-30 ng g(-1) wet weight). All of the OCs had linear concentration probability distributions on a log-normal basis which were used to evaluate exposure associated with these compounds as part of a probabilistic risk analysis. A linear dose/response relationship for the percentage reduction in the survival of young associated with DDE in eggs was developed. This probabilistic relationship was used to establish the threshold level (1000 ng g(-1) wet weight) at which there was a significant level of reduction in the survival of young above zero and the variability in DDE concentrations at this effect level. Using a threshold level of 1000 ng g(-1), the calculated Risk Quotient (RQ) had a 12.4% probability of RQ exceeding unity with the Night Heron, and 40.9% with the Little Egret. These results indicate that the DDTs in eggs would be expected to be associated with adverse effects on the survival of young of both species, particularly the Little Egret.
Publisher: Environmental Health Perspectives
Date: 07-2013
DOI: 10.1289/EHP.1206244
Publisher: Elsevier BV
Date: 04-1998
DOI: 10.1016/S0045-6535(97)10087-X
Abstract: The Environment Protection Department of Hong Kong has a monitoring program for persistent organic contaminants in sediments of Victoria Harbour, the main harbour of Hong Kong. A fugacity model has been used, based on this sedimentary data, to estimate inputs to the system (probably from sewage, stormwater and industrial discharges) as well as the fate of the contaminants, particularly in terms of the aqueous and biotic concentrations. The risk of deleterious effects on the natural marine system, as well as on the consumers of seafood from the system, was carried out using the estimated aqueous and biotic concentrations together with accepted environmental quality guidelines. The result of our analysis indicated that the chlorohydrocarbons, PCBs (as Aroclor 1254) total DDT and total HCH pose a significant risk, and probably have caused damage to the marine ecosystem as well as posing a hazard to seafood consumers. Much higher concentrations of the less toxic total alkanes, nonaromatic hydrocarbons, linear alkyl benzenes and the compounds giving a unresolved complex mixture (UCM) cannot be evaluated due to a lack of environmental guidelines and the complexity of these substances. However, it is probable that these substances add adverse effects to those due to the other contaminants.
Publisher: Elsevier BV
Date: 11-2006
DOI: 10.1016/J.ENVPOL.2005.12.028
Abstract: The Indo-Pacific humpback dolphin is considered threatened due to several factors including pollution in Hong Kong and the risks due to consumption of fish tainted with polychlorinated biphenyls (PCBs) and organochlorine pesticides were assessed. Six species of fish Collichthys lucida, Pseudosciaena crocea, Johnius sp., Thryssa sp., Mugil sp. and Trichiurus sp., which comprise the main prey species of humpback dolphins were collected for analyses. Risks due to total PCBs, total TEQs, PCB 118 and the pesticides were assessed with the use of toxicity reference values as the threshold reference benchmarks. The calculated risk quotients (RQs) showed that the risks associated with organochlorines were generally low. The highest RQ was associated with total TEQs suggesting that dioxin-like PCBs may pose the highest risk to the dolphins. The HCHs, total PCBs and heptachlor had comparatively high RQs and thus they should also be the priority organochlorines that would require further investigation.
Publisher: Springer Science and Business Media LLC
Date: 18-02-2016
DOI: 10.1007/S11356-016-6180-9
Abstract: The negative effects of overexposure to ultraviolet (UV) radiation in humans, including sunburn and light-induced cellular injury, are of increasing public concern. 4-Methylbenzylidene c hor (4-MBC), an organic chemical UV filter, is an active ingredient in sunscreen products. To date, little information is available about its neurotoxicity during early vertebrate development. Zebrafish embryos were exposed to various concentrations of 4-MBC in embryo medium for 3 days. In this study, a high concentration of 4-MBC, which is not being expected at the current environmental concentrations in the environment, was used for the purpose of phenotypic screening. Embryos exposed to 15 μM of 4-MBC displayed abnormal axial curvature and exhibited impaired motility. Exposure effects were found to be greatest during the segmentation period, when somite formation and innervation occur. Immunostaining of the muscle and axon markers F59, znp1, and zn5 revealed that 4-MBC exposure leads to a disorganized pattern of slow muscle fibers and axon pathfinding errors during the innervation of both primary and secondary motor neurons. Our results also showed reduction in AChE activity upon 4-MBC exposure both in vivo in the embryos (15 μM) and in vitro in mammalian Neuro-2A cells (0.1 μM), providing a possible mechanism for 4-MBC-induced muscular and neuronal defects. Taken together, our results have shown that 4-MBC is a teratogen and influences muscular and neuronal development, which may result in developmental defects.
Publisher: American Chemical Society (ACS)
Date: 30-08-2017
Abstract: The toxic effects of nanoparticles on in idual organisms have been widely investigated, while few studies have investigated the effects of nanoparticles on ubiquitous multicommunity microbial aggregates. Here, periphyton as a model of microbial aggregates, was employed to investigate the responses of microbial aggregates exposed continuously to Fe
Publisher: Elsevier BV
Date: 06-2011
Publisher: Elsevier BV
Date: 05-2008
DOI: 10.1016/J.CHEMOSPHERE.2008.01.032
Abstract: Polybrominated diphenyl ethers (PBDEs) and tetrabromobisphenol A (TBBPA) are brominated flame retardants that are produced in large quantities and are commonly used in construction materials, textiles, and as polymers in electronic equipment. Environmental and human levels of PBDEs have been increasing in the past 30 years, but the toxicity of PBDEs is not fully understood. Studies on their effects are relatively limited, and show that PBDEs are neurotoxins and potential endocrine disrupters. Hydroxylated (OH) and methoxylated (MeO) PBDEs have also been reported in the adipose tissue, blood and milk of wild animals and humans. In the present study, 15 PBDE metabolites, two BDE mixtures (DE71 and DE79), and TBBPA were studied in idually to determine their effects on ten steroidogenic genes, aromatase activity, and concentrations of two steroid hormones (testosterone and 17beta-estradiol) in the H295R human adrenocortical carcinoma cell line. Exposure to 0.05 microM 2'-OH-BDE-68 significantly induced the expression of CYP11A, CYP11B2, CYP17, CYP21, 3betaHSD2, 17betaHSD1, and 17betaHSD4, and the expression of StAR was induced by 6-OH-BDE-90 at the three exposure concentrations. Exposure to DE71 and DE79 resulted in dose-dependent trend towards induction, but these effects were not significant. Exposure to 0.5 microM 2-OH-BDE-123 and 2-MeO-BDE-123 resulted in significantly greater aromatase activity. However, none of the compounds affected sex hormone production at the concentrations tested. Generally, OH-BDEs had a much stronger ability to affect steroidogenic gene expression than MeO-BDEs.
Publisher: Elsevier BV
Date: 15-02-2008
DOI: 10.1016/J.TOXLET.2007.12.001
Abstract: Polybrominated diphenyl ethers (PBDEs) are additive flame retardants that have been found in the environment as well as human tissues. Environmental concentrations of these compounds have been increasing in many parts of the world in recent years. Due to their structural similarity, PBDEs are believed to have similar toxicity to PCBs, but their toxicological properties are still being determined. In this study, the steroidogenic effects of hydroxylated, methoxylated and/or chlorinated derivatives of PBDEs were assessed at both the gene and enzyme/hormone levels in the H295R human adrenocortical carcinoma cell line. The expression levels of 10 steroidogenic genes were measured using quantitative real-time PCR (Q-RT-PCR). Aromatase activity in the cells and sex steroid (testosterone (T) and 17beta-estradiol (E2)) concentrations in the culture medium were also measured. CYP11B2, which regulates the synthesis of aldosterone, was the most sensitive gene and was induced by most of the compounds tested in this study. CYP19 gene expression, aromatase activity, and E2 production were also affected by several metabolites, but no consistent relationship was observed between these endpoints. Several PBDE metabolites showed some potential ability to interfere with steroidogenesis, including 5-Cl-6-OH-BDE-47, a biologically relevant BDE-47 metabolite, which significantly decreased aromatase activity and E2 production at a concentration of 10 microM. The results of this study indicate that PBDE metabolites affect steroidogenesis in vitro and that they may have the potential to affect steroidogenesis and reproduction in whole organisms.
Publisher: Elsevier BV
Date: 2005
DOI: 10.1016/J.MARPOLBUL.2005.01.010
Abstract: Green-lipped mussels, Perna viridis, and Manila clams, Ruditapes philippinarum were sourced from "clean" sites in the Hong Kong region, depurated in a laboratory using uncontaminated filtered seawater for 8 days, and transplanted to a suspected gradient of chemically polluted sites in Hong Kong. After 14- and 28-days of field exposure, several antioxidant parameters including glutathione S transferase (GST), catalase (CAT), glutathione peroxidase (GPx), and glutathione (GSH) were quantified in gill and hepatopancreas tissues. Whole body tissue concentrations of polycyclic aromatic hydrocarbons (PAHs), petroleum hydrocarbons (PHCs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCs) were determined in pooled site s les. Chemical analyses indicated that: (a) clams had higher levels of PAHs, PHCs, DDTs and PCBs, whereas mussels had higher hexachlorocyclohexane (HCHs) and there was no difference between species for dieldrin and remaining OCs (b) Kat O should not be continued as a "clean" reference site for Hong Kong, because of the levels of contaminants measured and (c) PAH concentrations in the current survey were similar to those previously measured. Toxicological conclusions were: (a) antioxidant responses were different between species (b) CAT and GST have highest utility in clams for field use in Hong Kong, whereas CAT in both gill and hepatopancreas tissue showed most potential in mussels (c) significant induction of antioxidant responses over day 0 (excluding GPx in both tissues, and GST in mussel hepatic tissue) (d) groups of contaminants do not consistently induce antioxidant responses and (e) organochlorines and PCBs correlated significantly with CAT and GST in clam hepatopancreas and with CAT in mussel gill and hepatic tissue. Multivariate statistical techniques indicated little relationship between the site patterns for antioxidant responses and the contaminant gradients identified in body burden analysis.
Publisher: Elsevier BV
Date: 09-2008
Publisher: Elsevier BV
Date: 04-2021
Publisher: Elsevier BV
Date: 2008
DOI: 10.1016/J.MARPOLBUL.2008.02.032
Abstract: Polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCs) are generally present in the marine environment in complex mixtures. The ecotoxicological nature of contaminant interactions, however, is poorly understood, with most scientific observations derived from single contaminant exposure experiments. The objective of this experiment was to examine dose-response relationships between antioxidant parameters and body contaminant levels in mussels exposed to different exposure regimes under laboratory conditions. Accordingly, the green-lipped mussel, Perna viridis, was challenged with a mixture of PAHs (anthracene, fluoranthene, pyrene, benzo[a]pyrene) and OC pesticides (alpha-HCH, aldrin, dieldrin, p,p'-DDT) over a 4 week period. Contaminants were delivered under four different dosing regimes, with all treatments receiving the same total contaminant load by the end of the exposure period. Antioxidant biomarkers were measured after 1, 2, 3 and 4 weeks, including glutathione (GSH), gluathione-S-transferase (GST), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and lipid peroxidase (LPO). GST and CAT were induced in hepatic tissues in most of the exposure regimes, with the majority of significant induction occurring in a constant exposure regime and a two-step alternate exposure regime. Significant differences among exposure regimes were detected in the body burden of contaminants after 28 days. Hepatic CAT and GSH are proposed as potentially useful biomarkers as they showed good correlation with target contaminants and were not readily affected by different dosing patterns.
Publisher: Elsevier BV
Date: 02-2006
DOI: 10.1016/J.SCITOTENV.2005.02.018
Abstract: Carbon monoxide (CO) has a high affinity for haemoglobin and is a common cause of poisoning in industry and the home. Exhaled CO levels in patients with respiratory disease have been reported but exhaled CO in a large cohort of healthy subjects grouped by age and gender has not been reported. Exhaled CO levels and spirometry lung function data were recorded from 1032 subjects at a university c us and two commercial plazas. Subjects were also asked to complete a respiratory symptom questionnaire. Ninety-eight subjects reported respiratory disease and were excluded from the study. Non-smoking male subjects (n=508) had higher exhaled CO levels (4.36+/-2.54 ppm) [range 0-21 ppm] compared with female (n=348) subjects (3.72+/-2.12 ppm) [range 0-14 ppm] (p 60 years) had lower exhaled CO levels compared with young subjects (<22 years) (p=0.018). Over 13% of non-smokers had an exhaled CO greater than 7 ppm. Smokers showed significantly higher exhaled CO levels compared with non-smokers (p<0.0005) and smokers who complained of frequent cough and sputum production had higher levels of exhaled CO compared with smokers without such complaints. Smoking history (pack-years) was directly related to age (r=0.59) but correlated inversely with forced expiratory flow in the 1st second (FEV1) (r=-0.29) and peak expiratory flow rate (PEFR) (r=-0.25) (p<0.05). If a city's micro environmental CO concentrations and human activity patterns is available, regular monitoring of exhaled CO in healthy subjects has the potential to be used as a functional index of air pollution.
Publisher: Elsevier BV
Date: 07-2009
DOI: 10.1016/J.SCITOTENV.2009.03.033
Abstract: Muscle concentrations of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) were determined in rabbitfish Siganus oramin collected from Victoria Harbour and its vicinity, Hong Kong from 2004 to 2007. Spatially, relatively higher levels of [summation operator]PAH (1.05-4.26 microg g(-1)) and [summation operator]PCB (45.1-76.9 ng g(-1)) were determined in the central and western sites inside the harbour. Temporally, upward trend of [summation operator]PAH, accompanied with a proportion shift from high molecular weight to low molecular weight PAHs, was detected during the three-year study period, suggesting a heavier marine traffic in Victoria Harbour and its western region. However, human health risk assessment based on five in idual PAHs indicated that PAHs in fish muscles posed minimal health risk through consumption. In contrast, a downward trend of [summation operator]PCB was registered as the open use of PCBs has been banned. Despite this, the level of [summation operator]PCB in fish muscles still posed a health risk on the local people who have a high fish consumption rate. While seasonal influences on [summation operator]PAH/[summation operator]PCB accumulation in S. oramin seemed to be negligible, our findings in S. oramin were in line with the established PAH and PCB levels in sediments and/or mussels from the harbour, suggesting S. oramin can be used as a model fish species for monitoring PAHs and PCBs in the region.
Publisher: Elsevier BV
Date: 2008
DOI: 10.1016/J.MARPOLBUL.2008.02.035
Abstract: In order to test its ability as a bioaccumulator, the deposit feeding clam Asaphis deflorata, collected from a clean coastal area in Hong Kong (Ding Chau, Ma On Shan), was exposed to field-collected sediments representing a gradient of contamination. Sediments were collected from four sites, namely Shek O in the southeast of Hong Kong Island, Ap Lei Chau in Aberdeen district, Tai Kok Tsui in the Mong Kok waterfront, and To Kwa Wan near Kowloon City pier. Shek O was the cleanest and To Kwa Wan was the most polluted site. Replicate 30L fiberglass tanks containing equal numbers of organisms were maintained for 28 days, with equal quantities of sediment and filtered seawater. Prior to this the animals were depurated for 10 days in clean sediment. During the 28-day holding period, s ling of both sediment and clams was performed on days 0, 10 and 28, along with condition index measurements. Concentrations of organochlorine pesticides and PCBs in sediments showed that Shek O was the cleanest of the sites, followed by Ap Lei Chau, Tai Kok Tsui and To Kwa Wan. There were marked differences among the sites, especially in PAH concentrations, with To Kwa Wan showing extremely high sediment concentrations. Following exposure, the biota concentrations of various organochlorine pesticides and PCBs suggested that there was sediment concentration-dependent accumulation by A. deflorata on day 10 of the experiment. However, there was no significant increase on day 28 for any of the compounds tested. Contaminant concentrations in clams feeding on Shek O sediments were minimal and almost the same on all s ling days, indicating the presence of only baseline contaminant concentrations. The condition indices (CI) of the clams on various s ling days showed that the animals were relatively more stable in sediment from Shek O. There were some deaths in all the test tanks (including those containing Shek O sediments). In addition, clams appeared to bury faster in the cleaner Shek O sediment and remained buried, unlike those in the sediment from the other locations, where some remained predominantly on the surface. Nevertheless, despite not completely burying, the clams in other test sediments still exhibited sediment concentration-dependent tissue accumulation. The results of the investigation indicate the possibility of developing a standard test protocol for bioaccumulation by sediment dwelling invertebrates, for practical use in Hong Kong, using A. deflorata.
Publisher: Springer Science and Business Media LLC
Date: 2002
Abstract: The feathers of two Ardeid species, the Little Egret (Egretta garzetta) and the Black-crowned Night Heron (Nycticorax nycticorax) were collected from six egretries and two egretries respectively, located in different areas in the New Territories of Hong Kong, including the Mai Po Marshes (within a Ramsar site). These feathers were digested and concentrations (microg/g dry weight) of copper (4.6-19.4), iron (8.1-641.3), manganese (0.4-19.4), zinc (51.3-183.5), lead (0.1-5.1), cadmium (0.01-0.15), chromium (0.06-1.7) and mercury (0.0-7.1) were determined by ICP-AES, ICP-MS and CVAAS. The levels of manganese, mercury and lead found were equal to or less than the concentrations found in previous investigations, reflecting a slight downward trend most apparent with lead. As a general rule, the levels of lead and mercury were higher in the egretries close to the polluted Deep Bay. A probabilistic risk assessment of the possible adverse effects on the breeding success of the Little Egret was carried out with respect to mercury, lead and cadmium. It was concluded that mercury (0.5-7.1 microg/g dry weight feathers) probably has had adverse effects at the Au Tau egretry of the Little Egrets, but there was no evidence of adverse effects at other egretries. The probabilistic analysis also indicated a low likelihood of adverse effects of mercury on the breeding of the Black-crowned Night Herons at A Chau (0.3-1.2 microg/g) and Mai Po Village (0.0-1.4 microg/g). The evidence for the effects of lead and cadmium was limited but suggested there may possibly be adverse effects with lead but not cadmium.
Publisher: Elsevier BV
Date: 2008
DOI: 10.1016/J.MARPOLBUL.2008.04.002
Abstract: Photosystem II (PSII) herbicides have been shown to affect the photosynthesis of corals at low, environmentally relevant concentrations. The recent detection of the PSII herbicide Irgarol-1051 in coastal waters of Hong Kong at concentrations above the EC(50) for reduction of photosynthesis of corals prompted further investigation into the extent of PSII herbicide pollution in coral reefs of Hong Kong. Snap-shot and passive s les were taken from coral reef sites and evaluated via HPLC/MS-MS and a novel bioanalytical technique. Low concentrations (less than 10 ng L(-1)) of diuron and atrazine were found at all study sites. Extracts from these s les concentrated by a factor of 10 were found to reduce the photosynthetic yield of zooxanthellae. It appears unlikely that herbicide pollution is a key issue in isolation but may act synergistically with other stressors to reduce the viability of Hong Kong's coral reefs. The study has also demonstrated the feasibility of combining s le extraction techniques with a coral specific bioanalytical technique for a sensitive assessment of risks associated with herbicide exposure in corals.
No related grants have been discovered for Kwan Sing Paul LAM.