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ABSTRACT: Two sediment cores were collected from Hailing Bay located in a typical mariculture zone of Guangdong Province, South China, and analyzed for polycyclic aromatic hydrocarbons (PAHs). The concentrations of the sum of 27 PAHs ranged from 62 to 1200 ng g(-1) dry wt, and sediment in the study area was considered to be moderately polluted by PAHs. Source diagnostics based on PAH composition and principal component analysis suggested that PAHs in the study area were mainly derived from petroleum combustion, with discharge of PAHs from fishing boats as an important source. Ecological risk assessment results indicate that PAHs in sediment of the present study currently have minimal adverse effect on the mariculture environment. Comparison of sedimentary inventory of PAHs in the fish harbor of the study area with those in the Pearl River Estuary and the coastal Bohai Bay indicate that the sediment has become an important reservoir of PAHs.
Journal of Environmental Monitoring 08/2012; 14(10):2685-91. · 1.99 Impact Factor
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ABSTRACT: Existing evidence indicated that dichlorodiphenyltrichloroethane (DDT)-containing antifouling paints were an important source of DDT residues to mariculture zones. However, the magnitude of the impact on aquafarming environment has remained largely unknown. In the present study, the concentrations of DDT and its metabolites (designated as DDXs) were determined in harbor sediment and antifouling paint samples collected from a typical mariculture zone in South China. Compositional and concentration correlation analyses implicated the DDT-containing antifouling paints for fishing boat maintenance as an important source of DDT in the mariculture zone. The annual emission of DDXs to the study region was estimated at 0.58 tons/yr. Furthermore, a comparison of the expected DDT loadings in pelagic fish and field measurements indicated that fish feed especially trash fish was a major source of DDTs in the fish body. Nevertheless, the use of DDT-containing antifouling paints should be limited to prevent further deterioration in aquafarming environment.
Environmental pollution (Barking, Essex: 1987) 08/2011; 159(12):3700-5. · 3.43 Impact Factor
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ABSTRACT: Although the production and use of dichlorodiphenyltrichloroethane (DDT), a legacy component of persistent organic pollutants, have been highly restricted worldwide, the environmental fate of DDT has remained a great concern as it is not only ubiquitous and bioaccumulative but can also be degraded to a series of metabolites that may be more hazardous ecologically. The present study, taking advantage of the abundant levels of DDT and its metabolites in a subtropical coastal region of China, investigated into the degradation pathways of DDT in natural coastal sediment. Sediment profiles indicated that degradation of 1,1,1-trichloro-2,2-bis-(p-chlorophenyl)ethane (p,p'-DDT) to 1,1-dichloro-2,2-bis-(p-chlorophenyl)ethane (p,p'-DDD) mainly occurred in sediment of the top 20 cm layer. 1,1-dichloro-2,2-bis-(p-chlorophenyl)ethylene (p,p'-DDE), aerobically transformed from p,p'-DDT prior to sedimentation, was likely to degrade to 1-chloro-2,2-bis-(p-chlorophenyl)ethylene (p,p'-DDMU) which was further converted to 2,2-bis(p-chlorophenyl)ethylene (p,p'-DDNU). In addition, p,p'-DDNU could be transformed to 2,2-bis(p-chlorophenyl)ethane (p,p'-DDNS) and other high-order metabolites. On the other hand, the conversions of p,p'-DDD to p,p'-DDMU and 1-chloro-2,2-bis-(p-chlorophenyl)ethane (p,p'-DDMS) to p,p'-DDNU were deemed slow in anaerobic sediment. Therefore, the present study confirmed all the degradation pathways involving reductive dechlorination and p,p'-DDE being a more important precursor for p,p'-DDMU than p,p'-DDD in anaerobic sediment, as proposed previously. On the other hand, the present study suggested that p,p'-DDMU instead of p,p'-DDMS was more likely the precursor for formation of high-order metabolites. Based on the current assessments, use of (DDD+DDE)/DDTs to indicate whether there is fresh DDT input may lead to large uncertainties if the concentrations of high-order metabolites are not negligible. Similarly, ecological risk assessment associated with DDT should be conducted with consideration of high-order DDT metabolites.
Environmental Science & Technology 06/2011; 45(12):5245-52. · 4.80 Impact Factor
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ABSTRACT: This study examined the potential sources of persistent halogenated compounds (PHCs), including organochlorine pesticides, mainly DDXs (sum of o,p'- and p,p'-DDT, -DDD, and -DDE and p,p'-DDMU) and polybrominated diphenyl ethers, to typical aquaculture environments of South China, determined the relative importance of gill diffusion and fish feeding for exposure of fish to these contaminants and assessed potential health risk for global consumers via consumption of fish from South China. Fish feed is generally a direct and important source of PHCs in both freshwater and seawater aquaculture. In addition, gill diffusion is the predominant uptake route for PHCs (except p,p'-DDMU, o,p'-DDD and -DDT) in farmed freshwater fish, whereas accumulation from the diet is the major route for farmed marine fish. Risks to health of global consumers via consumption of fish from South China are minimal. However, increased risk can be foreseen due to continuous use of brominated fire retardants and electronic waste importation to China.
Environment international 05/2011; 37(7):1190-5. · 4.79 Impact Factor
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ABSTRACT: Air, rain, pond water, bank soil, pond sediment, fish feed, and fish were sampled from four freshwater cultured fish ponds (FWCFPs) in rural areas within the Pearl River Delta (PRD) of South China. Compositional analyses indicated that historical residues were the main sources of DDXs (defined as the sum of dichlorodiphenyltrichloroethane (DDT), dichlorodiphenyldichloroethane (DDD), and dichlorodiphenyldichloroethylene (DDE) and 1-chloro-2,2-bis(4-chlorophenyl)ethane (p,p'-DDMU)), and hexachlorocyclohexanes (HCHs) in the FWCFPs. The input fluxes to the FWCFPs were estimated at 4.0, 1.6, 15, and -0.92 µg/m(2) ·year for DDXs and 3.8, 0.92, 2.9, and -1.4 µg/m(2) ·year for HCHs for dry deposition, wet deposition, feeding, and net air-water exchange in Dongguan, and 3.8, 1.2, 137, and -1.2 µg/m(2) ·year for DDXs and 3.6, 0.66, 5.0, and -1.0 µg/m(2) ·year for HCHs in Shunde, respectively. These results indicated that fish feed was the dominant input source of DDXs to the FWCFPs. As for HCHs, fluxes via dry deposition and feeding were similar and slightly higher than those via wet deposition. Biological effects due to the occurrence of DDXs in the FWCFPs were minimal, and consumption of freshwater fish from the PRD appeared to pose insignificant risk to human health based on some existing regulations and guidelines.
Environmental Toxicology and Chemistry 02/2011; 30(6):1272-7. · 2.81 Impact Factor
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ABSTRACT: Samples of two seawater farmed fish (crimson snapper (Lutjanus erythopterus) and snubnose pompano (Trachinotus blochii)), water, air, sediment, fish feed, macroalgae and phytoplankton were collected from two estuarine bays (Daya Bay and Hailing Bay) in South China. The concentrations of persistent halogenated compounds (PHCs) including polybrominated diphenyl ethers (PBDEs), organochlorine pesticides and polychlorinated biphenyls (PCBs) varied widely with the different sample matrices under investigation. The compositional patterns in fish, fish feed, macroalgae and phytoplankton, as well as the good correlations between the abundances of p,p'-DDT and BDE-209 and their metabolites (i.e., p,p'-DDD and p,p'-DDE for p,p'-DDT and BDE-47 for BDE-209) in fish indicated the occurrence of DDT and PBDE biotransformation in fish body. Finally, the marine aquaculture environment in South China is somewhat biologically impaired by DDT-contaminated water, sediment and fish feed, and there may be some cancer risk associated with fish consumption for humans, especially for urban residents.
Marine pollution bulletin 01/2011; 63(5-12):572-7. · 2.63 Impact Factor
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ABSTRACT: The concentration levels of typical persistent organic pollutants such as polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs) including dioxin-like PCBs (DL-PCBs) and non-dioxin-like PCBs, organochlorine pesticides (OCPs), and polybrominated diphenyl ethers (PBDEs) in global aquatic products from major producing countries were summarized. Daily intakes of these compounds via consumption of various aquatic products for global consumers were also estimated based on available literature data. Risk assessment based upon existing criteria for OCPs and PBDEs shows that there is minimal risk to global consumers from consumption of aquatic products, with the exception of products from specific regions located around known heavy-point sources. Exposure to dioxins through consumption of aquatic products, excluding marine fish, is also in the range of the acceptable level, lower than 4 pg World Health Organization toxic equivalent (WHO-TEQ)/kg bw/d; however, dioxin intake via marine fish may cause hazards to human health, especially for Europeans. Regarding PCBs, there is cancer risk for global consumers via consumption of aquatic products, especially marine fish, based on cancer and noncancer hazard ratio assessment. Generally, European consumers have higher exposure levels of PCDD/Fs and DL-PCBs, while Americans and Asians have relatively higher exposure levels of OCPs and PCBs. In contrast, all global populations are found to have lower exposure levels of PBDEs, which may be attributed to its relatively shorter history of use compared with PCBs and OCPs. Finally, the estimated total amounts of PCBs, OCPs, and PBDEs stored in global aquatic products constitute only a small portion of the total amount that has been used, and the majority obviously occurs in other environmental media or even remains in commercial products.
Environmental Toxicology and Chemistry 10/2010; 29(10):2135-42. · 2.81 Impact Factor
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ABSTRACT: 1-Chloro-2,2-bis(4-chlorophenyl)ethene (p,p'-DDMU), a metabolite of either 1,1-dichloro-22-bis(4-chlorophenyl)ethane (p,p'-DDD) or 1,1-dichloro-2,2-bis(4-chlorophenyl)ethene (p,p'-DDE), which is degraded from 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (p,p'-DDT), was detected in a variety of environmental matrices of the Pearl River Delta (PRD), South China, including fish, fish feeds, semidigested fish stomach contents, marine surface sediment, surface soil, atmospheric gaseous phase, and particulates, rainwater, and coastal rainwater. Forfish species,the concentrations of p,p'-DDMU were significantly higher in farmed fish than in marine wild fish, with the highest value obtained in seawater farmed fish species (mear/median values of 262/173 ng/g lipid). The relative abundance of p,p'-DDMU to total DDTs (sum of o,p'- and p,p'-DDT, DDD, and DDE) was higher in samples of marine origin (approximately 5%) than in those of terrestrial origin (approximately 2%). Because p,p'-DDD was considerably abundant in all samples and a negative linear correlation was found between p,p'-DDD/(p,p'-DDD + p,p'-DDE) and p,p'-DDMU/DDTs in the marine sediments (r2 = 0.73) and seawater farmed fish (r2 = 0.29) under investigation, it is possible that DDMU was partially dehydrochlorinated from DDD in the environment of the PRD. A fugacity-based assessment suggested that p,p'-DDMU is likely to transport from sediment to seawater and then to air and from soilto air. The ubiquity of p,p'-DDMU in the PRD indicates that it may also be widespread worldwide particularly in countries with large amounts of DDT used currently and/or historically. Given the potential risk of p,p'-DDMU to human health, more efforts should be directed toward to this previously overlooked contaminant
Environmental Science and Technology 06/2009; 43(9):3073-9. · 5.23 Impact Factor
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ABSTRACT: Persistent halogenated hydrocarbons (PHHs), including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs), in fish feeds (including trash fish and compound feed) manufactured in South China, were analyzed. PHHs were ubiquitous in fish feeds, with the concentrations of OCPs, PBDEs, and PCBs at the upper, mid, and lower levels of the global range. Trash fish generally contained higher concentrations of DDXs (sum of o,p'- and p,p'-DDT, -DDD, and -DDE and p,p'-DDMU), especially p,p'-DDT and low-brominated PBDEs, while compound feeds had higher concentrations of highly brominated BDEs, e.g., BDE-209. In addition, no concentration difference of HCHs and PCBs was found between trash fish and compound feeds. The habit of direct use of trash fish as fish feeds has induced the accumulation of DDXs in aquatic species in China, and trash fish collected in South China seemed to be slightly hazardous to wildlife because of the concentrations of DDXs. The results from the present study suggest that the use pattern of fish feeds in China may have to be adjusted to minimize contamination of fishery products and wildlife by PHHs. Use of compound feeds produced with controlled procedures should be encouraged, whereas that of trash fish should be restricted, at least for now.
Journal of Agricultural and Food Chemistry 04/2009; 57(9):3674-80. · 2.82 Impact Factor
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ABSTRACT: To ascertain the bioactivity and to analyse quantificationally the denervating action of botulinum toxin A (BTXA) in gel.
36 Sprague-Dawley rats were randomized into four groups. In group A - D, the gastrocnemius muscle of one leg was randomly selected to receive injection of BTXA solution 5U in 0.1 ml, BTXA gel 12.5U in 0.1 ml, BTXA gel 5U in 0.1 ml and BTXA gel 2U in 0.1 ml respectively, while the gastrocnemius muscle of other leg was injected with 0.1 ml of saline solution in group A and 0.1 ml of gel in group B to group D as control. Compound muscle action potential (CMAP) of both gastrocnemius muscles were measured and the amplitudes were recorded before injections, and 5 days, 2 weeks, 3 weeks, 1 month, 2 months and 3 months after the injections respectively.
The reduction of CMAP amplitude was significantly different at various time (P < 0.01), and CMAP amplitude decreased significantly after the treatment of BTXA (P < 0.01). The reduction of CMAP amplitude was significantly dif ferent in group A to I) (P < 0.01), and more reduction was found in group A and B (P < 0.01), and the reduction was higher in group C than in group D (P < 0.05). However, there were no significant differences in the reduction of CMAP amplitude between group A and group B.
Bioactivity of BTXA in gel was showed and the denervating action of BTXA in gel was demonstrated in a dosage and time dependent manner.
Zhongguo ying yong sheng li xue za zhi = Zhongguo yingyong shenglixue zazhi = Chinese journal of applied physiology 02/2008; 24(1):104-7.
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ABSTRACT: To investigate the clinical features, diagnosis and the management of masked bilateral superior oblique palsy (MBSOP).
Retrospectively analyzed the records of all 7 patients that met the clinical criteria for MBSOP in Zhongshan Ophthalmic Center between 1999 and 2003. The head tilt, vertical deviation in primary position and the action of obliquus pre- and postoperatively were collected in detail.
All 7 patients were diagnosed as unilateral SOP in the first time. The average hypertropia in primary position preoperatively was 19.7(Delta) (range 6(Delta) to 30(Delta)). All patients had a head tilt, obvious unilateral inferior oblique overaction (+2 to +4) and mild superior oblique underaction (-1 to -2), and normal action in contralateral superior and inferior obliquus. Initial surgery consisted of ipsilateral inferior oblique weakening with (5 patients) or without (2 patients) ipsilateral superior rectus recession. The average hypertropia in primary position was 12.0(Delta) (range 0(Delta) to 20(Delta)) after the first operation. In 1 week to 4 years, all of the previously masked eye presented the inferior oblique overaction (+2 to +3) and superior oblique underaction (0 to -1). All patients underwent a second surgery in 4 months to 4 years after the initial surgery. The average hypertropia in primary position was 2.3(Delta) (range 0(Delta) to 7(Delta)) after the second operation. Postoperative alignment was excellent in all patients.
Masked bilateral superior oblique palsy is quite difficult to detect before surgical correction of the initial manifest palsy. The possibility of an occult contralateral palsy should be considered in all undergoing surgery for unilateral SOP. The superior rectus recession and the inferior oblique weakening procedure should be performed at different stages. When the masked palsy becomes evident, a successful surgical outcome can usually be expected.
[Zhonghua yan ke za zhi] Chinese journal of ophthalmology 02/2007; 43(1):27-31.
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ABSTRACT: To investigate the features and treatment of V patterns strabismus.
Pre- and post-operative deviation and oblique muscle action as well as binocular visual function were evaluated in sixty-three V pattern patients. The difference between upgaze and downgaze of deviation were recorded before and after operation.
Sixty-two patients (98.4%) with binocular or unilateral inferior oblique overaction + 2 to + 3 were treated with inferior oblique weakening procedure and horizontal rectus recession-resection procedure. 1 patient with binocular inferior oblique overaction + 1 treated with horizontal recti recession-resection procedure. The difference between upgaze and downgaze is 25.6 prism diopters (PD) preoperatively and 4.5 PD postoperatively. The primary-position exotropia preoperatively of 48 V pattern exotropia is 37.2 PD, after surgery, the average deviation is 3.4 PD of esotropia [38 cases (79.2%) with deviation within +/- 10 PD]. 15 cases of V pattern esotropia had deviation 50.6 PD preoperatively, after surgery, the average deviation is 2.4 PD of esotropia [11 cases (73.3%) with deviation within 10 PD]. 21 patients (33.3%) obtained stereo visual function after surgery.
V patterns always had inferior oblique over action and could be treated with the inferior oblique weakening procedure. The primary-position deviation should be treated by traditional horizontal rectus recession-resection procedure. The stereoscopic function had a good prognosis with surgery.
[Zhonghua yan ke za zhi] Chinese journal of ophthalmology 08/2005; 41(7):585-9.
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ABSTRACT: To understand the clinical significance of subjective and objective examination of cyclodeviations and investigate the effect of weakening inferior oblique muscles on the status of ocular torsion.
Twenty patients (40 eyes) with overacting inferior oblique muscles underwent bilateral myotomy or partial myectomy of inferior oblique muscles. Subjective cyclodeviations were measured before surgery as well as one week, two months after surgery by double maddox rod test (DMRT). Objective cyclodeviations were assessed by fundus photography before and 7 days after surgery in 15 cases. The photograph was transferred to a computer, and the fovea-disc angle was measured by means of drawing picture software.
Nine patients with primary overaction of inferior oblique muscles were negative with DMRT before surgery, and only one case revealed incyclotropia 5.0 degrees tested two months after surgery. Four out of 11 patients with secondary overaction of inferior oblique muscles showed excyclotropia 2.5 degrees - 5.0 degrees with DMRT before surgery, and all patients indicated no subjective cyclotropia with DMRT two months after surgery. Fundus photography determination of the right eye revealed extorsion 16.83 degrees +/- 6.39 degrees, the left eye 14.92 degrees +/- 4.51 degrees before surgery. The reduction of the cyclodeviations by weakening inferior oblique muscle for the right and left eye was 13.07 degrees +/- 3.38 degrees and 10.54 degrees +/- 3.75 degrees respectively. The comparison of objective ocular torsion for both eyes showed high significant differences (P < 0.01) pre- and post-operatively.
The results of subjective and objective examination of cyclodeviations in patients with primary or secondary overacting inferior oblique muscle early after birth were not consistent. Weakening inferior oblique muscle could correct excyclodeviation. There exist complicated compensatory mechanisms for subjective change of ocular torsion after surgery. The changes of subjective and objective cyclodeviations are still inconsistent.
[Zhonghua yan ke za zhi] Chinese journal of ophthalmology 05/2004; 40(4):243-6.
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ABSTRACT: This review summarizes and analyzes available data in the literature (mostly after 2000) on the occurrence of dichlorodiphenyltrichloroethane (DDT) and its main metabolites, dichlorodiphenyldichloroethane (DDD) and chlorodiphenyldichloroethylene (DDE), in the environment of the Pearl River Delta (PRD), South China. Generally, the concentration levels of the sum of DDT, DDD, and DDE, designated as DDTs thereafter, have not significantly declined since 1983. However, the composition of DDTs residues has changed with time. DDTs in soil, freshwater sediment and freshwater fish species were mainly residues from chronological use. There is evidence that new point sources, such as dicofol and anti-fouling paint, may have contributed DDTs to various environmental compartments. Risk assessment against existing criteria indicated that the levels of DDTs in water and some fish species may pose adverse effects to humans or wildlife, and those in sediment/soil may also cause negative impacts to the eco-environment of the PRD.
Environmental Pollution.
