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1.
The current state of concentrations of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) in China is presented. While products that are known to degrade to either PFOS or PFOA have been used in China, concentrations in environmental media have been reported to be relatively low across China. Greater concentrations of PFOS and PFOA were observed in southern and eastern China than in other areas of China. Concentrations of PFOS and PFOA were relatively great in the Huangpu River, with concentrations of 20.5 ng l?1 and 1590 ng l?1, respectively. Surface waters of Dongguan and Shanghai were more contaminated by PFOS and PFOA than that of other cities. Dongguan was the only city in China in which PFOS value in surface water exceeded the water quality criterion, while PFOA concentration in Shanghai was 152 ng l?1. Similar to other contaminants, point-source pollution was also the common pattern of PFOS and PFOA contamination. Concentrations of PFOS in human blood in China were relatively greater in China than other countries, with drinking water contamination given as the most likely source. Concentrations of PFOS in human blood have increased from the 1980s to the 2000s, while such a trend was not observed for PFOA.  相似文献   

2.
A systematic survey of organochlorine pesticides (OCPs) including hexachlorocyclohexane isomers (α-HCH, β-HCH, γ-HCH, δ-HCH and ΣHCH) and dichlorodiphenyltrichloroethane metabolites (p,p′-DDT, p,p′-DDE, o,p′-DDT, p,p′-DDD and ∑DDT) in soils along the north coastal areas of the Bohai Sea, China, has been lacking. In this study, 31 representative surface soil samples were collected along the north coastal and riverine areas of the Bohai Sea to characterise the potential for adverse effects of ∑HCH, ∑DDT and their individual isomers and transformation products. Concentrations of ΣHCH and ΣDDT in soils ranged from less than the limit of detection (1 ng · g?1 dw (mean: 3.5 ng · g?1 dw) and2 ng · g?1 dw (mean: 1.7 × 101 ng · g?1 dw), respectively. Compared with studies of OCPs in soils from other locations, concentrations of HCHs and DDTs observed in this study were moderate. Concentrations of OCPs observed in soils were generally less than proposed reference values. HCH residues were a mixture of historical technical HCH and current lindane sources. The pattern of DDTs was consistent with historical releases of technical DDTs. Selected soil physicochemical properties did not explain the sorption and/or partitioning of HCHs or DDTs.  相似文献   

3.
Perfluorinated compounds (PFCs) are ubiquitously distributed in the environment mainly as perfluoro-carboxylic acids (PFCAs) and perfluoroalkyl sulfonates (PFASs). In this paper, six PFCAs and two PFASs were quantified in surface and tap water samples from 12 sites around Lake Taihu near Shanghai City in East China. Predominant PFCs were perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), of which the concentration ranges were 6.8–206 and 1.2–45 ng·L−1, the geometric means were 35.3 and 9.4 ng·L−1, and the median (quartile range) values were 31.4 (34.4) and 10.4 (10.7) ng·L−1, respectively. Other PFCs were also detected but in much lower concentrations than PFOA. The sources of the PFCs were expected to be direct industrial discharges in the Lake Taihu area, and this area was also a possible source of PFCs contaminations in Shanghai district in the downstream. PFCs distributions were found different in the upstream, downstream and north part of Lake Taihu. Occurrences of PFCs in the tap water in Lake Taihu area indicated their exposure to the local people. A brief estimation of the environmental risks by PFCs implied no acute or immediate risks from PFCs to local human health, but chronic risks from PFOA in the tap water should be considered in the downstream regions.  相似文献   

4.
Spatial distribution, sources and potential health risks of organochlorine pesticides (OCPs), including hexachlorocyclohexane (HCH) and dichlorodiphenyltrichloroethane (DDT), in surface soils (n = 544) collected from a typical alluvial plain of the Yangtze River Delta region, China, were elucidated. Concentrations of ΣHCH and ΣDDT in soils ranged from less than the limit of detection (<LOD) to 99.0 ng g?1, dry weight (dw) (mean 3.23 ng g?1 dw) and <LOD to 600 ng g?1 dw (mean 88.8 ng g?1 dw), respectively. Historical applications of HCH and DDT were the major sources of the residue in soils. HCH was mainly distributed in Anthrosols in the southern part of the watershed, while DDT was mainly distributed in Cambosols in the northern part. The 95 % cumulative probability incremental lifetime cancer risks (ILCRs) of different age groups such as children, youths, and adults all exceeded the acceptable risk level of 10?6 recommended by USEPA for carcinogenic chemicals. The spatial distributions of ∑ILCRs were consistent with concentrations of OCPs in soils, while they were slight different for the different age groups. Adult females had the greatest risk of OCPs in soils, followed by children, while youths had the least risk. The ingestion of OCPs in soils was the more important route of exposure compared with dermal and inhalation exposures. The concentration of OCPs in soils, the particulate emission factor, the fraction of dermal exposure ratio, and the soil ingestion rate were the major contributing variables to total ILCRs according to sensitivity analyses.  相似文献   

5.
全氟辛烷羧酸(perfluorooctanoic acid,PFOA)和全氟辛烷磺酸(perfluorooctyl sulfonate,PFOS)等长链全氟化合物(perfluorinated compounds,PFCs)具有持久性、生物累积性和毒性,近年来发现一些短链PFCs具有相对较短的半衰期,可以成为PFOA和PFOS的替代品,这些物质包括C4和C6结构的PFCs,如全氟丁烷羧酸(perfluorobutanoic acid,PFBA)、全氟己烷羧酸(perfluorohexanoic acid,PFHx A)、全氟丁烷磺酸(perfluorobutyl sulfonate,PFBS)和全氟己烷磺酸(perfluorohexyl sulfonate,PFHx S)。为解析我国城市污水厂短链PFCs污染水平和地域分布特征,本研究调查了我国不同地区17座城市污水处理厂的进水、二沉出水和污泥中4种短链PFCs的分布和浓度水平。结果表明4种短链PFCs、PFOA和PFOS在17座污水厂进水中检出率均为100%(6种目标物单体浓度范围:0.19~274.72 ng·L-1);污泥中PFOS和PFOA检出率为100%(PFOS:2.08~72.31 ng·g-1,PFOA:1.03~24.81 ng·g-1),PFBA、PFHx A检出率为100%(0.60~3.33 ng·g-1),PFBS和PFHx S的检出率分别为42.11%和63.16%。在污水厂进水中,将PFOA和PFOS与其同类的短链PFCs浓度进行比较,发现短链PFCs分别相对于PFOA和PFOS的比例最高可达93.47%和94.57%。4种短链PFCs、PFOA和PFOS的地域分布差异明显,总浓度呈现出华东、华南地区高于西北、东北、华北地区的趋势,其中华东地区调查的污水处理厂浓度最高。污水厂4种短链替代物主要通过污水排放,不同污水厂的日排放总量(污泥和出水)为0.25~273.07 g·d-1,万吨水排放量范围为0.04~1.37 g。研究将为我国全氟化合物替代物污染和控制提供数据基础和科学依据。  相似文献   

6.
An artificial soil method was applied to study the effects of perfluorooctane sulphonate (PFOS) and perfluorooctanoic acid (PFOA) on earthworms (Eisenia fetida). Survival, growth inhibition and damage to DNA of earthworms were detected after 14 d acute exposure. The 14 d-LC50 of PFOS and PFOA was 478.0?mg·kg?1 dw and 759.6?mg·kg?1 dw, respectively, indicating that they were of low toxicity. Both PFOS and PFOA could significantly inhibit the growth of earthworms after 14 d exposure, and growth inhibition rates increased with the greater concentrations of PFOS or PFOA, showing a dose–response relationship (PFOS: r?=?0.951, P r?=?0.962, P?P?50 of PFOS was lower than that of PFOA, the growth inhibition rate of earthworm exposed to PFOS was higher than that exposed to PFOA at the same concentration level, and the median values of TL, CL and OTM in PFOS treatments were also higher than those in PFOA treatments. In conclusion, both these fluorine compounds were moderately toxic to earthworms, but the PFOS effect was greater than that of PFOA.  相似文献   

7.
Perfluorinated compounds in a coastal industrial area of Tianjin,China   总被引:5,自引:0,他引:5  
Perfluorinated compounds (PFC) in water, sediment, soil, and biota from the coastal industrial area of Tianjin, China, were measured to provide baseline information and to determine possible sources and potential risk to wildlife. Perfluorooctanesulfonate (PFOS) was the predominant PFC with maximum concentrations of 10 ng/L in water, and 4.3, 9.4, and 240 ng/g dw in sediment, soil, and fish, respectively. Perfluorooctanoate (PFOA) concentration in water ranged from 3.0 to 12 ng/L. Perfluoroundecanoate (PFUnA) and Perfluorododecanoate (PFDoA) were detected in solid matrices, respectively, at concentrations of 相似文献   

8.
北江流域抗生素污染水平和来源初探   总被引:1,自引:0,他引:1  
北江是发源于湖南(武水)和江西(浈水),汇于广东韶关,流经广东全境并入海的三大河流之一。为了解整个北江抗生素污染情况,共设置44个采样点,并采集了河水及部分沉积物样品,较全面地分析了各样品中12种典型抗生素含量并初步探究了其污染来源。研究发现,包括北江源头在内的全河段均有抗生素的检出,5类抗生素在表层水和沉积物中的平均浓度分别为77.8 ng·L~(-1)和3.6 ng·g~(-1)。其中,大环内酯类污染最为严重,其含量范围为11.7~114.6 ng·L~(-1)和0~435.3 ng·g~(-1),远高于其他类抗生素。表层水中磺胺类的磺胺甲恶唑和氯霉素类的检出率达100%,其中以磺胺甲恶唑(14.7 ng·L~(-1))和阿奇霉素(25.0 ng·L~(-1))为主,而沉积物中以阿奇霉素(35.9 ng·g~(-1))、氧氟沙星(5.4 ng·g~(-1))和四环素(3.3 ng·g~(-1))为主。由于流域污染源种类和数量不同,各抗生素在北江中的分布也存在差异。表层水中抗生素含量水平表现为下游高于上中游,在沉积物中则主要集中于中、下游之间河段。这反映了人类活动强度对北江抗生素污染的直接影响。  相似文献   

9.
Persistent organic pollutants (POPs) were recorded in sediment and fish samples collected from the western coast of Alexandria. Total hydrocarbons (aliphatic+PAHs ) in sediment ranged from 683.8 to 34670.1 ng g ?1 with an average of 9286.9 ng g ?1. The sum of C16–C34 of aliphatic fractions was<4000?ng g;?1, indicating the presence of a fresh petroleum source. For all sediments, the anthracene/phenanthrene ratio was>0.1, suggesting the dominance of a pyrolytic source. Total aliphatics in different fish species ranged from 253 to 11?132 ng g;?1, while total PAHs ranged from 3862 to 35?746 ng g;?1 wet weight. Benzo[a]pyrene was the most dominant PAH fraction ranged from 1902.7 to 32 905.5 with an average of 9464.5?ng g;?1 wet weight in all fish species. Concentrations of polychlorinated biphenyls (PCBs) ranged from 0.79 to 64.9?ng g;?1 with an average 12.14?ng g;?1 wet weight. The concentrations of organochlorines in fish species (Euthynnus alleferatus, Scomberomorus commerson, Sphyraena Sphyraena, Diplodus vulgaris, and Alepes djedaba) decreased following the order: PCBs>DDTs>HCHs>total cyclodienes. Concentrations of DDTs in fish tissues ranged from 4.89 to 36.37 ng g?1 with an average of 16.4?ng g;?1 wet weight. The concentrations of total HCHs ranged from 0.3 to 65.7?ng g;?1 with an average of 16.35?ng g;?1. The present study indicates: (1) fresh petroleum input where Pr/Ph>1; (2) PAHs in sediment<4000 ng g ?1; (3) BaP concentration exceeded the permissible levels in Alepes djedaba species; (4) DDTs in sediment were below the effective range low level; (5) PCBs>effective range low and相似文献   

10.
Concentrations of perfluorooctane sulfonate (PFOS) were measured for the first time in major rivers within southwest, Nigeria. PFOS was concentrated from water and sediment using solid-phase extraction, identified and quantified with high-performance liquid chromatography coupled with tandem mass spectrometry. Concentrations of PFOS ranged from 1.71 to 16.19 ng L?1 in water, and from 1.64 to 10.29 ng g?1 in sediments across all locations. Comparatively, the concentrations of PFOS observed in this study were within the range ever measured in the environment. Field-based sediment water distribution coefficients (log Kd, L kg?1) ranged from 2.08 to 3.56. While no correlation was observed between Kd and organic carbon contents, there was significant positive correlation between Kd and salinity (r2 = 0.7867), which suggested that activities capable of increasing salinity can enhance PFOS removal from the environment.  相似文献   

11.
Xijiang River is an important drinking water source in Guangxi Province, China. Along the Xijiang River and surrounding tributary, the pollution profile of three important groups of semi-volatile organic compounds, including polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) and phthalate esters (PAEs), was analyzed. Relatively low levels of PAHs (64–3.7 × 102 ng L?1) and OCPs (16–70 ng L?1), but high levels of PAEs (7.9 × 102–6.8 × 103 ng L?1) occurred in the water. Comparatively, low levels of OCPs (39–1.8 × 102 ng g?1) and PAEs (21–81 ng g?1), but high levels of PAHs (41–1.1 × 103 ng g?1) were found in sediment. Principal component analyses for source identification indicated petroleum-derived residues or coal and biomass combustion, and vehicular emission was the main sources for PAHs. The OCPs sources of each category were almost independent, whereas the new input of HCHs and p,p′-DDTs probably existed in some areas. PAEs were mainly originated from personal care products of urban sewage, plastic and other industrial sources. Ecological risk through the risk quotient analysis indicated a small or significant potential adverse effect on fish, daphnia and green algae. Nevertheless, the integrated risk of all pollutants should be taken into account in future study.  相似文献   

12.
The total concentrations of 16 United States Environmental Protection Agency (US EPA)-listed polycyclic aromatic hydrocarbons (PAHs) found in coastal and estuarine sediments along the northern shores of the Bohai and Yellow Seas, China, at any study location varied from 0.236 to 8.34 nM g?1 dry weight (dw). For a given PAH, concentrations varied by one to two orders of magnitude. Ecological risk assessments based on biota–sediment accumulation factors (BSAFs) indicated that the potential ecological hazard of PAHs in the sediments was limited. The average total sediment PAH concentrations were less than the effects range low, indicating that PAHs currently present in the sediments were not harmful to aquatic organisms. The estimated PAH concentration in the aquatic organisms was 0.223 nM g?1 and posed a limited threat to human health via biological concentration from sediment to harvest of the sea. Assuming no additional PAH inputs, 99% of the 16 PAH molecules currently present in the sediments would be degraded in 40 years.  相似文献   

13.
云南省会泽县农田土壤中全氟化合物污染特征研究   总被引:4,自引:0,他引:4  
为探究云南省会泽县农田土壤中全氟化合物(perfluorinated compounds,PFCs)的污染特征及其潜在来源,2015年6月采集云南省会泽县农田土壤42份,利用高效液相色谱-串联质谱仪(HPLC-MS/MS)分析了11种PFCs的含量水平。结果表明,云南省会泽县农田土壤中全氟己酸(perfluorohexanoic acid,PFHx A)、全氟庚酸(perfluoroheptanoic acid,PFHp A)和全氟己烷磺酸(perfluorohexane sulfonate,PFHx S)均未检出,其余8种PFCs(ΣPFCs)的平均含量水平为0.392 ng·g-1,含量范围为0.298~0.998ng·g-1。全氟辛酸(perfluorooctanoic acid,PFOA)和全氟辛烷磺酸(perfluorooctane sulfonate,PFOS)是最主要的PFCs,相对百分含量范围为45.93%~81.86%,其平均含量水平分别为0.116 ng·g-1和0.120 ng·g-1。与国内其他地区土壤中PFCs的含量水平相比,云南省会泽县农田土壤中PFCs含量水平低于上海,与广州、深圳、东莞、安徽、中国东部农村等地区土壤中PFCs的含量相当。主成分分析结果表明,以全氟癸酸(perfluorodecanoic acid,PFDA)、全氟辛烷磺酸(PFOS)和全氟十三酸(perfluorotridecanoic acid,PFTr DA)为主要标志物的2个主成分可以解释云南省会泽县农田土壤中73%的ΣPFCs。工业活动、大气沉降及长距离传输为云南省会泽县农田土壤中PFCs的主要来源。  相似文献   

14.
为了揭示海陆衔接区环境中抗生素与抗性细菌分布特征及其内在相关性,以莱州湾及其主要入海河流为研究区域,利用HPLC-MS/MS分析样品中15种磺胺类抗生素(SAs)和6种喹诺酮类抗生素(QNs)的浓度,并通过改良的Method 1604(US EPA)评估海水与沉积物中2种典型水传病原微生物大肠杆菌(E.coli)与金黄色葡萄球菌(S.aureus)的抗生素抗性水平,进而探讨该区域水体中抗性菌株的分布特点以及微生物抗性率与相应抗生素浓度的相关性。结果显示,莱州湾水体与沉积物中普遍存在磺胺与喹诺酮类抗生素残留及抗性污染问题。两大类抗生素在水体中平均残留浓度分别为3.89 ng·L~(-1)(SAs)和234.68ng·L~(-1)(QNs),在沉积物中分别为0.91 ng·g~(-1)(SAs)和49.37 ng·g~(-1)(QNs),且分布特征基本呈现自河流向海洋逐渐递减的趋势,说明河流输入是莱州湾抗生素污染的主要来源。在水体中,具有磺胺类抗性的E.coli和S.aureus平均检出量分别达到2 018和4 683 CFU·L~(-1),抗性率范围分别在0%~37.3%和10.6%~45.8%之间;而2种喹诺酮类抗性病原微生物的平均检出量则相对较低,分别为1 315 CFU·L~(-1)(E.coli)和1 461 CFU·L~(-1)(S.aureus),抗性率分别为0%~50.0%和0%~20.8%;此外,相比于E.coli,S.aureus为沉积物中的主要抗性病原微生物,磺胺与喹诺酮类抗性S.aureus检出率均高于80%,平均检出量分别为24CFU·g~(-1)和18 CFU·g~(-1)。相关性分析表明,莱州湾近岸海域水体中磺胺类抗生素浓度与磺胺类抗性微生物总量之间具有良好的线性关系,然而其与微生物抗性率之间并未表现出相似的规律,说明近岸海洋环境中抗生素的残留量不是影响抗性菌株丰度的唯一因素。  相似文献   

15.
全氟化合物(PFASs)作为一类新型的有机污染物,因具有持久性、可长距离传输、生物蓄积性和生物毒性等POPs特性,近年来得到全世界的广泛关注。本文以北京市水源地(密云水库和官厅水库)为研究区域,采用固相萃取(SPE)前处理与高效液相色谱串联质谱联用(HPLC-MS/MS)相结合的方法,分析测定了鱼样品中包括全氟辛烷磺酸(PFOS)、全氟辛酸(PFOA)、全氟丁酸(PFBA)、全氟丁烷磺酸(PFBS)等在内的12种PFASs的含量。利用同位素法确定了不同种类鱼的营养级关系,研究不同营养级中的PFASs浓度及生物放大效应,重点对全氟辛烷磺酸(PFOS)与全氟辛酸(PFOA)的生态风险以及对人体的健康风险进行评价。结果表明:北京市水源地的鱼体中的PFASs存在不同程度的检出,其中,全氟辛烷磺酸(PFOS)、全氟辛酸(PFOA)、全氟壬酸(PFNA)、全氟癸酸(PFDA)、全氟十一酸(PFUdA)和全氟十二酸(PFDoA)的检出率均达到100%,PFASs总量浓度达1.70~14.32 ng·g~(-1) wet weight(w.w.),PFOS和长链全氟羧酸PFCAs是鱼体中的主要污染物。同位素鉴定水库鱼的营养级层次范围在2.11~4.10,且肉食性鱼类营养级大多高于杂食性鱼类,PFOS沿着食物链生物放大的过程与稳定碳氮同位素富集过程基本同步。此外,采用人均日摄入量法(average daily intake,ADI)评估得到PFOS与PFOA的风险值分别为1.16 ng·kg~(-1)·d~(-1)和0.31ng·kg~(-1)·d~(-1),整体低于人均每天可承受摄入量(tolerable daily intake,TDI),结果表明,北京水源地鱼体中PFOS和PFOA含量未达到对生态系统和人体健康具有风险的水平。  相似文献   

16.
生产企业及周边环境中全氟化合物的污染特征   总被引:4,自引:0,他引:4  
生产企业作为全氟化合物(perfluorinated compounds,PFCs)的直接来源地,现今被认为是PFCs污染的主要来源之一,同时其对周边环境具有更加直接而重大的影响。我国对生产企业周边环境中PFCs污染特性研究的报道较缺乏,补充丰富各地生产企业周边环境的PFCs污染特征,可为PFCs点源分析和污染溯源提供依据。以湖北省孝昌县某化工有限公司为典型生产企业,采集7个采样点的水体和土壤样品,分析典型地区环境介质中PFCs的污染现状与特征。结果显示,11种目标PFCs污染物在水体中有7种、土壤中有6种不同程度地检出,环境水体中PFCs的总浓度介于4.70~40.22μg·L-1,土壤中PFCs的总浓度介于58.22~2 075.60 ng·g-1之间。全氟辛基磺酸(PFOS)为典型行业周边水体和土壤中最主要的PFCs污染物,其次是水体中的全氟己基磺酸钾(PFHx S)、全氟丁烷磺酸钾(PFBS)和土壤中的全氟辛酸(PFOA)、全氟己基磺酸钾(PFHx S)。PFCs检出浓度的大小与采样点距典型企业的距离极其相关,距离与污染物总量之间呈显著负相关性,但周边环境中PFCs的种类和构成比,不受与点源之间距离的影响。  相似文献   

17.
This study presents metal levels in the sediments of the Bakar Bay, with its main goal to evaluate recent anthropogenic influence, as well as over previous decades. Sediment profiles at 7 sampling points were taken. Chemical contents in bulk sediment were obtained using ICP, ICP-MS, and AAS methodologies, and 20 most significant elements were presented. Concentrations of selected elements were evaluated by factor statistical analyses to identify their source. Also, metal enrichment factor and geoaccumulation index were calculated, and spatial distribution maps for three sediment layers were constructed. Measured metal concentrations in sediment were compared with concentrations in other sediments from the Adriatic Sea. In addition, a set of sediment quality guidelines were also applied in order to predict the probability of adverse biological effects on the benthic community: This was found not to be very serious. Factor analysis clearly demonstrates the segregation between metals of natural origin resulted from soil and bedrock weathering (Li, Al, Cr, Sc), and with two anthropogenic sources originating from the city of Bakar and bulk cargo terminal (Hg, Pb, Zn, Ag, Sn, and Fe). Mercury (max 0.65 μg g?1) is found to be the heaviest contaminant, followed by lead (max 71.5 μg g?1), copper (89.3 μg g?1), and zinc (156 μg g?1). However, this study shows that Bakar Bay is considerably less polluted with toxic metals than it was believed.  相似文献   

18.
The purpose of this study was to evaluate polychlorinated biphenyls (PCBs) contamination levels in roe and red deer from north-western Poland and to assess environmental pollution in this area. A quantitative analysis was conducted using a capillary gas chromatography/mass spectrometry method. The mean concentrations of ΣPCBs (sum of PCBs: 28, 52, 101, 138, 153, 180) in liver samples were 30.24±12.35 ng·g?1 of lipid weight (l.w.) in roe deer and 60.13±14.23 ng·g?1 l.w. in red deer, compared with 24.21±10.02 and 45.22±9.77 ng·g?1 in the lungs of roe and red deer, respectively. PCBs 138, 153 and 180 were the dominant congeners in the liver samples of the analysed animals, whereas PCB 138 and 153 in the lungs. TEQs levels calculated for only dioxin-like PCBs were low: 0.32 and 0.29 pg WHO-PCB-TEQ·g?1 fat in liver of red deer and roe deer, respectively. The mean PCB concentrations obtained in our study for organs of roe deer and red deer were several times lower than those reported elsewhere. These findings show that the investigated roe and red deer originated from an area with low levels of PCB contamination.  相似文献   

19.
Microwave-hydrothermal treatment of persistent and bioaccumulative perfluorooctanoic acid (PFOA) in water with persulfate (S2O 8 2? ) has been found effective. However, applications of this process to effectively remediate PFOA pollution require a better understanding on free-radical scavenging reactions that also take place. The objectives of this study were to investigate the effects of pH (pH = 2.5, 6.6, 8.8, and 10.5), chloride concentrations (0.01?C0.15 mol·L?1), and temperature (60°C, 90°C, and 130°C) on persulfate oxidation of PFOA under microwave irradiation. Maximum PFOA degradation occurred at pH 2.5, while little or no degradation at pH 10.5. Lowering system pH resulted in an increase in PFOA degradation rate. Both high pH and chloride concentrations would result in more scavenging of sulfate free radicals and slow down PFOA degradation. When chloride concentrations were less than 0.04 mol·L?1 at 90°C and 0.06 mol·L?1 at 60°C, presence of chloride ions had insignificant impacts on PFOA degradation. However, beyond these concentration levels, PFOA degradation rates reduced significantly with an increase in chloride concentrations, especially under the higher temperature.  相似文献   

20.
The overall effect of the number of boats on the copper (Cu) levels in the water column and sediment, along with their spatial variability within Shelter Island Yacht Basin (SIYB), San Diego Bay, California was examined. We identified a horizontal gradient of increasing dissolved Cu and Cu in sediment from outside to the head of SIYB which was coincident with the increasing number of boats. Spatial models of Cu distribution in water and sediment indicated the presence of ‘hotspots’ of Cu concentration. From outside to the head of SIYB, dissolved Cu ranged from 1.3 μ g L?1 to 14.6 μ g L?1 in surface water, and 2.0 μ g L?1 to 10.2 μ g L?1 in bottom water. Cu in sediment exceeded the Effect Range Low of 34 mg kg?1 (i.e. where adverse effects to fauna may occur), with a peak concentration of 442 mg kg?1 at the head of the basin. Free Cu++ in surface water was several orders of magnitude higher than in sediment porewater. High-resolution data of Cu species together with probability maps presented in this paper will allow managers to easily visualise and localise areas of impaired quality and to prioritise which areas should be targeted to improve Cu-related conditions.  相似文献   

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