首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
瓯江鱼类资源调查及保护对策   总被引:1,自引:0,他引:1  
瓯江是浙江省第二大江,鱼类资源丰富,然而至1972年调查以来,尚未有全面的鱼类资源调查研究。对瓯江干流从上游查田镇至下游海口镇的5个采样点进行了较全面的鱼类调查,共采集鱼类标本1 246尾,隶属于5目14科46属60种。相比1972年调查结果,有34种未采集到,其中包括列入中国濒危动物数据库的4种:中华鲟、鲥、香鱼、花鳗鲡;本次调查结果较1972年调查新增19种,其中外来鱼类2种:莫桑比克罗非鱼、大口黑鲈。在对5个采样点的鱼类组成、群落相似度、优势种组成、生物多样性指数等进行分析后,发现瓯江上游鱼类种类以流水性鱼类为主,且生物多样性较高;中下游鱼类种类组成以静水性鱼类为主,且生物多样性较低。本次调查的每日单船渔获量为45 kg/(船·d),仅为1972年的25%,鱼类资源衰退严重。最后,对鱼类资源下降的原因进行了分析,并提出了保护对策  相似文献   

2.
Although various single-concentration measurements of the pharmaceutical diclofenac are available in literature, detailed information on the mass flux in the aquatic environment is often missing. Therefore, the overall load of diclofenac was obtained by recording each concentration in nine effluents of sewage treatment plants (STP) and at three river sites located in the area of the river Main (Germany) over a time period of six weeks.In STP effluents, concentrations of up to 2200 ng/L were obtained. In combination with flow rates and connected population an average specific load per capita and day of 0.28 mg (+/? 0.11 mg) diclofenac reaches the receiving water course. This average specific load per capita is an expressive parameter to assess main diclofenac exposure to the aquatic environment avoiding uncertainties of estimated data commonly used in exposure assessment. Accordingly, predicted environmental concentrations (PEC) of 140 ng/L for a realistic worst case scenario and 2 to 52 ng/L based on water quality modeling were derived. Since concentrations of up to 140 ng/L were observed in surface water, the obtained PEC is in perfect agreement with measured concentrations. Hence, comparing the PEC with published predicted no effect concentrations (PNEC), chronic adverse effects in fish populations may occur.  相似文献   

3.
Some twenty nuclear sites are located along the Rhône. A radioecological study of the river has been in progress since 1974 and a brief outline is given here of its hydrological, chemical, sedimentological and biological features. The techniques used for sampling, processing and radioactivity measurement in fish are also described. A summary of the results demonstrates the influence of the nuclear power stations and fuel cycle plants on the evolution of radioactivity levels in fish as a function of time or distance from liquid waste discharge points.Comparison with data for the Meuse shows that at the present time activities in fish downstream of the nuclear power stations are comparable in both rivers. Levels are, however, higher in the Rhône downstream from the Marcoule reprocessing plant. The data collected in situ together with the results of laboratory experiments demonstrate the mechanisms of transfer of radionuclides into the aquatic environment and supply information for the protection of environmental health.  相似文献   

4.
We evaluated the health condition of a temperate river during June-November 1999 through applications of the index of biological integrity (IBI) using fish assemblages and qualitative habitat evaluation index (QHEI) as well as chemical analyses. Overall IBI values ranged from 13 to 37 and averaged 23 (n = 25, standard error = 1.16), indicating a "poor" or "very poor" condition according to the criteria of modified Karr [Fisheries 6 (1981) 21]. The values of mean IBI declined at a rate of 0.22 km(-1) (R2 = 0.91, p < 0.05) along the longitudinal distance from the headwaters to the downstream sites. Reduced IBI values at downstream sites reflected low forest cover, high population density and high nutrient enrichments. Ecotoxicity tests using the river water also showed that toxic impacts were evident in the downriver sites. These factors resulted in decreases of riffle benthic species and insectivores and increases of tolerant species, anormalies and exotic species in the river. Spatial pattern in IBI agreed with QHEI values, which showed a linear relation (R2 = 0.998, p < 0.001) with species richness. Field measurements of conductivity and pH, an indicators for variation of conservative ions, showed that the river water was diluted by 40% fold by summer monsoon rain and surface run-off from the watershed, resulting in a physical and chemical instability during the monsoon. For these reasons, average IBI values during the monsoon and postmonsoon decreased >20% compared to the premonsoon, indicating that IBI values were also affected by flow regime. Based on the overall physico-chemical data and IBI values, the river health is rapidly degrading due to the combined effect of chemical contaminations and habitat modifications.  相似文献   

5.
Ten different perfluoroalkyl acids (PFAAs), including perfluooctane sulfonate (PFOS), were measured in 30 common carp (Cyprinus carpio) fillets collected from three sites on the Upper Mississippi River in Minnesota in an effort to evaluate the potential impact of PFAA emissions in this area. Samples upstream of the city of St. Cloud (reference site) had median PFOS concentrations of 8.1 ng/g wet weight (ng/g wet wt), but median levels increased significantly downstream in the Minneapolis-St. Paul urban area, with concentrations from the Pig's Eye Lake site at 26 ng/g wet wt (p=0.0015) and the Spring Lake site at 40 ng/g wet wt (p=0.0004). This latter PFOS concentration is within the advisory range for limiting fish consumption to one meal a week according to the Minnesota Department of Health. Other PFAAs were also found to increase significantly between the reference site and the Minneapolis-St. Paul area, but maximal concentrations remained below 2.0 ng/g wet wt. This study demonstrates the bioaccumulation of PFAAs in a ubiquitous fish species in a major urban area known to have historical inputs of various PFAA compounds. The full extent of this contamination and the potential for accumulation in other species remain to be evaluated.  相似文献   

6.
The concentrations of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) were determined in a number of foodstuffs purchased in various locations near a hazardous waste incinerator (HWI) in Tarragona County (Catalonia, Spain). The dietary intake of PCDD/Fs by the population of the area under potential influence of the HWI was subsequently estimated. The results were compared with previous surveys performed in the same area in 1998 (baseline), 2002 and 2006. In the present study, the highest WHO-TEQ corresponded to industrial bakery (0.183 ng/kg wet weight, ww), followed by fish (0.156 ng/kg ww), oils and fats (0.112 ng/kg fat weight), and seafood (0.065 ng/kg ww). In contrast, the lowest values were observed in pulses and tubers (0.003 ng/kg ww), and cereals and fruits (0.004 ng/kg ww). The dietary intake of PCDD/Fs by the general population was 33.1 pg WHO-TEQ/day, having fish and seafood (11.6 pg WHO-TEQ), oils and fats (4.61 pg WHO-TEQ), dairy products (3.79 pg WHO-TEQ), and industrial bakery (3.49 pg WHO-TEQ) as the groups showing the highest contribution to the total TEQ. The lowest daily contributions corresponded to pulses (0.08 pg WHO-TEQ) and tubers (0.25 pg WHO-TEQ). This intake was considerably lower than that found in the baseline study, 210.1 pg I-TEQ/day, and also notably lower than that found in the 2002 survey (59.6 pg I-TEQ/day), but slightly higher than the intake estimated in the 2006 survey, 27.8 pg WHO-TEQ/day. The results of this study show that any increase potentially found in the biological monitoring of the general population living in the area under evaluation should not be attributed to dietary exposure to PCDD/Fs.  相似文献   

7.
The level and identity of [14C] residues in bluegills (Lepomis macrochirus)_exposed to 2.5 mg/L [14C] triclopyr (3,5,6-trichloro-2-pyridinyloxyacetic acid) have been determined. The highest level of radioactivity observed in the flesh of a fish at any time point (0.13 mg/kg, calculated as equivalent mg triclopyr/kg fish) was less than 5% of the fish exposure level of 2.5 mg/L, while the maximum level in the remainder (head, skin, and viscera) was about 95% (2.33 mg/kg) of the fish exposure level, indicating no concentrating effect. The principal components observed in the fish tissues were triclopyr, 3,5,6-trichloro-2-pyridinol, 2-methoxy-3,5,6-trichloropyridine and a conjugate. These components accounted for greater than 75% of all the residues observed.  相似文献   

8.
Levels of polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDs), and polychlorinated biphenyls (PCBs) were measured in several fish species originating from the river Scheldt (Belgium). Five sampling locations were chosen in a highly industrialized area along the river, while two ponds in the vicinity of the river served as reference sites. The present study is a follow-up of a survey performed in 2000 which reported extremely high levels of PBDEs and HBCDs in eel (Anguilla anguilla) collected from the same region (Oudenaarde, Flanders). The sum of tri- to hepta-BDE congeners (2270+/-2260 ng/g lipid weight (lw), range 660-11500 ng/g lw) and total HBCDs (4500+/-3000 ng/g lw, range 390-12100 ng/g lw) were one order of magnitude higher than levels usually reported from freshwater systems, indicating the presence of point sources. In most samples, levels of total HBCDs were higher than those of PBDEs, probably due to the high density of factories using HBCD as an additive brominated flame retardant (BFR). The high values of HBCDs were confirmed by both gas- and liquid-chromatography-mass spectrometry. Although BFR levels were between the highest ever reported in freshwater ecosystems, PCBs could be detected at even higher concentrations (16000+/-14300 ng/g lw, range 3900-66600 ng/g lw), being among the highest levels recorded in Belgium. The inter-sampling site variation of PBDEs, HBCDs and PCBs was comparable. All locations presented similar PBDE congener profiles, with BDE 47 being the dominant congener, followed by BDE 100, BDE 99 and BDE 49, probably originating from the former use of the penta-BDE technical mixture. In order to estimate the impact of these point sources on human exposure, we further focussed on eels which showed a considerable decrease in the PBDE and HBCD levels between 2000 and 2006. Due to the wide span in concentrations between the different sampling locations, a variable contribution to the total human exposure through local eel consumption was estimated. The calculated daily intake ranged from 3 ng to 330 ng PBDEs/day for normal eel consumers, but was as high as 9800 ng PBDEs/day for anglers, which may be considered at risk.  相似文献   

9.
Per- and poly-fluorinated compounds (PFCs), which include perfluorinated carboxylates (PFCAs) and sulfonates (PFSAs) and various precursors, are used in a wide variety of industrial, commercial and domestic products. This includes aqueous film forming foam (AFFF), which is used by military and commercial airports as fire suppressants. In a preliminary assessment prior to this study, very high concentrations (> 1 ppm wet weight) of the PFSA, perfluorooctane sulfonate (PFOS), were discovered in the plasma of snapping turtles (Chelydra serpentina) collected in 2008 from Lake Niapenco in southern Ontario, Canada. We presently report on a suite of C6 to C15 PFCAs, C4, C6, C8 and C10 PFSAs, several PFC precursors (e.g. perfluorooctane sulfonamide, PFOSA), and a cyclic perfluorinated acid used in aircraft hydraulic fluid, perfluoroethylcyclohexane sulfonate (PFECHS) in surface water from the Welland River and Lake Niapenco, downstream of the John C. Munro International Airport, Hamilton, Ontario, Canada. Amphipods, shrimp, and water were sampled from the Welland River and Lake Niapenco, as well as local references. The same suite of PFCs in turtle plasma from Lake Niapenco was compared to those from other southern Ontario sites. PFOS dominated the sum PFCs in all substrates (e.g., > 99% in plasma of turtles downstream the Hamilton Airport, and 72.1 to 94.1% at all other sites). PFOS averaged 2223 (± 247.1 SE) ng/g in turtle plasma from Lake Niapenco, and ranged from 9.0 to 171.4 elsewhere. Mean PFOS in amphipods and in water were 518.1 (± 83.8) ng/g and 130.3 (± 43.6) ng/L downstream of the airport, and 19.1 (± 2.7) ng/g and 6.8 (± 0.5) ng/L at reference sites, respectively. Concentrations of selected PFCs declined with distance downstream from the airport. Although there was no known spill event or publicly reported use of AFFF associated with a fire event at the Hamilton airport, the airport is a likely major source of PFC contamination in the Welland River.  相似文献   

10.
Sulfonamides (SAs) have become one of the antibiotic families most frequently found in all kind of environmental waters. In the present work, the presence of 16 SAs and one of their acetylated metabolites in different water matrices of the Ebro River basin has been evaluated during two different sampling campaigns carried out in 2007 and 2008. Influent and effluent samples from seven wastewater treatment plants (WWTPs), together with a total of 28 river water samples were analyzed by on-line solid phase extraction-liquid chromathography-tandem mass spectrometry (on-line SPE-LC-MS/MS). Sulfamethoxazole and sulfapyridine were the SAs most frequently detected in WWTPs (96-100%), showing also the highest concentrations, ranging from 27.2 ng L(-1) to 596 ng L(-1) for sulfamethoxazole and from 3.7 ng L(-1) to 227 ng L(-1) for sulfapyridine. Sulfamethoxazole was also the SA most frequently detected in surface waters (85% of the samples) at concentrations between 11 ng L(-1) and 112 ng L(-1). In order to assess the effectiveness of the wastewater treatment in degrading SAs, removal efficiencies in the seven WWTPs were calculated for each individual SA (ranging from 4% to 100%) and correlated to the corresponding hydraulic retention times or residence times of the SAs in the plants. SAs half-lives were also estimated, ranging from to 2.5 hours (sulfadimethoxine) to 128 h (sulfamethazine). The contribution of the WWTPs to the presence of SAs depends on both the load of SAs discharging on the surface water from the WWTP effluent but also on the flow of the receiving waters in the discharge sites and the dilution exerted; WWTP4 exerts the highest pressure on the receiving water course. Finally, the potential environmental risk posed by SAs was evaluated calculating the hazard quotients (HQ) to different non-target organisms in effluent and river water. The degree of susceptibility resulted in algae>daphnia>fish. Sulfamethoxazole was the only SA posing a risk to algae in effluent water, with an HQ>7.  相似文献   

11.
Parabens are alkyl esters of p-hydroxybenzoic acid and are used as antimicrobial preservatives in a range of consumer products, including cosmetics, pharmaceuticals, and foodstuffs. Despite their widespread use, prior to this study, paraben concentrations in foodstuffs from China and human dietary exposure to these chemicals have been unknown. In this study, concentrations of six parabens were determined in 13 categories of food samples (n = 282), including cereals and cereal products, meat, fish and seafood, eggs, dairy products, bean products, fruits, vegetables, cookies, beverages, cooking oils, condiments, and others, collected from nine cities in China. Almost all (detection rate: 99%) food samples contained at least one of the parabens analyzed, and the total concentrations (ΣParabens; sum of six parabens) ranged from below limit of quantification (LOQ) to 2530 ng/g fresh weight, with an overall mean value of 39.3 ng/g. Methyl paraben (MeP), ethyl paraben (EtP), and propyl paraben (PrP) were the major paraben analogs found in foodstuffs, and these compounds accounted for 59%, 24%, and 10%, respectively, of ΣParaben concentrations. Although the mean concentrations of ΣParabens varied among different categories of food items (from 0.839 ng/g in beverages to 100 ng/g in vegetables), the concentrations were not statistically significant among the 13 food categories, including canned foodstuffs. Estimated daily intake (EDI) of parabens was based on the measured concentrations in foods and the corresponding daily food ingestion rates. The mean and 95th percentile values for EDI were 1010 and 3040 ng/kg body weight (bw)/day for adult men and 1060 and 3170 ng/kg bw/day for adult women, respectively.  相似文献   

12.
Triclosan (TCS) is an antimicrobial agent widely used in many personal care products. This study investigated the occurrence of TCS in effluents, biosolids and surface waters, and its fate in wastewater treatment plants (WWTPs). The aqueous concentrations of TCS in nineteen effluents from Australian WWTPs ranged from 23 ng/L to 434 ng/L with a median concentration of 108 ng/L, while its concentrations in nineteen biosolids ranged from 0.09 mg/kg to 16.79 mg/kg on dry weight basis with a median concentration of 2.32 mg/kg. The removal rates for TCS in five selected WWTPs were found to range between 72% and 93%. Biological degradation was believed to be the predominant removal mechanism for TCS in the WWTPs. However, adsorption onto sludge also played a significant role in the removal of TCS in the WWTPs. TCS at concentrations up to 75 ng/L was detected in surface waters (outfall, upstream, and downstream) from five rivers receiving effluent discharge from WWTPs. Preliminary risk assessment based on the worst-case scenario showed that the TCS concentrations in surface waters might lead to risks to aquatic organisms such as algae. Based on the TCS levels in the biosolids, application of biosolids on agricultural land may also cause adverse effects in the soil environment.  相似文献   

13.
建设过鱼设施是减缓河流大坝修建对鱼类不利影响的重要措施。本文以江家口坝址至坝下580 m处的河段为研究区段,构建基于MIKE21的平面二维水动力模型,根据工程的水文情势选用典型工况对坝下流场进行分析,探究不同工况下鱼类可能的上溯路径。结果表明:主流流量在5.40~40.74 m3/s,集诱鱼流量在2.50 m3/s情况下,主流受集诱鱼进口流量约束,将偏向右岸往下游流动。在仅考虑2号机组下泄17.67 m3/s流量下,河道存在目标鱼类洄游的上溯路线,距集诱鱼进口30~100 m处,河道中间满足鱼类适宜流速和水深,鱼类将沿着河道中间洄游;距集诱鱼进口0~30 m处,右岸流速逐渐升高并成为鱼类适宜流速,鱼类将从右岸洄游并最终到达集诱鱼进口;集诱鱼进口处,右岸水深高于中间水深约10%~40%,高于左岸水深90%~170%,集诱鱼进口处的高水深将有利于鱼类进入。对于“T”形集诱鱼进口汇流,集诱鱼流量占12%左右能产生较好的集诱鱼进口水力学特征。研究成果可为集诱鱼进口处鱼类上溯提供参考依据。  相似文献   

14.
Persistent organic pollutants (POPs) present in the living environment are thought to have detrimental health effects on the population, with pregnant women and the developing foetus being at highest risk. We report on the levels of selected POPs in maternal blood of 155 delivering women residing in seven regions within the São Paulo State, Brazil.The following selected POPs were measured in the maternal whole blood: 12 polychlorinated biphenyls (PCBs) congeners (IUPAC Nos. 99, 101, 118, 138, 153, 156, 163, 170, 180, 183, 187, 194); dichlordiphenyltrichloroethane p,p′-DDT, diphenyldichloroethylene p,p′-DDE and other pesticides such as hexachlorocyclohexanes (α-HCH, β-HCH, γ-HCH), hexachlorobenzene (HCB), chlordane derivatives cis-chlordane, trans-chlordane, oxy-chlordane, cis-nonachlor and trans-nonachlor.Statistical comparisons between regions were performed only on compounds having concentrations above LOD in 70% of the samples. PCB118 congener was found to be highest in the industrial site (mean 4.97 ng/g lipids); PCB138 congener concentration was highest in the Urban 3 site (mean 4.27 ng/g lipids) and congener PCB153 was highest in the industrial and Urban 3 sites with mean concentration of 7.2 ng/g lipids and 5.89 ng/g lipids respectively. Large differences in levels of p,p′-DDE between regions were observed with the Urban 3 and industrial sites having the highest concentrations of 645 ng/g lipids and 417 ng/g lipids, respectively; β-HCH was found to be highest in the Rural 1 site; the γ-HCH in Rural 1 and industrial; the HCB in the Rural 1 and industrial sites and oxy-chlordane and t-NC in the Rural 2 sites. An association between levels of some contaminants and maternal age and parity was also found.  相似文献   

15.
16.
Concentrations of 14 polybrominated diphenyl ether (PBDEs) and 28 polychlorinated biphenyl (PCBs) congers were measured in 137 samples of fish and meat from Nanjing, a city in the Yangtze River Delta, China. Total concentrations of PBDEs were less in fish (mean of 180 pg/g ww; range 8.0–1100 pg/g ww), but more in non fish foods (mean of 180 pg/g ww; range 15–950 pg/g ww) than those reported from other countries. The total dietary intake of PBDEs and PCBs by humans were 9.9 ng PBDE/d and 870 ng PCB/d, respectively. The daily intake by a 60 kg adult of 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TEQWHO) from PCBs was estimated to be 49 pg PCBTEQWHO/d (0.82 pg PCBTEQWHO/kg bw), which is less than the tolerable daily intake suggested by the World Health Organization (WHO). The daily intake of meat and fish accounted for 57.2% and 42.8% of the total intake of PCBTEQWHO.  相似文献   

17.
The occurrence, removal and bioaccumulation of steroid estrogens such as the natural estrone (E1), 17β-estradiol (E2) and estriol (E3), as well as the synthetic 17α-ethynylestradiol (EE2) were investigated in Dianchi Lake catchment, China. The results show that traditional secondary treatment processes in eight sewage treatment plants (STPs) of Kunming were not efficient enough to completely remove steroid estrogens, but ultraviolet (UV) photodegradation in advanced treatment displayed more effectively for the removal of the residual compounds. The amount of total steroid estrogens (∑ SEs) discharged to Dianchi Lake catchment by the eight STPs was 35.8 g/day, in which STP-3 was the dominant source, accounting for 50.8%. Because of the pollution input from treated and untreated sewages, estrogens were widely detected in surface water and sediment samples collected from 21 inflow rivers of Dianchi Lake, 10 National Surface Water Quality Monitoring Sites of the lake itself and its unique outflow river, with the mean concentration of ∑ SEs in the range of 5.3–798.2 ng/L (water) and 3.7–202.4 ng/g (dry weight, sediment), 1.5–39.2 ng/L (water) and 2.7–20.9 ng/g (sediment), and 4.2 ng/L (water) and 6.6 ng/g (sediment), respectively. Due to the continuous input of estrogens to Dianchi Lake from STPs and inflow rivers, present estrogen levels in various tissues of wild fish species sampled from the lake (2013) were higher than the values detected in the previous years (2009 and 2010). The bioaccumulation of steroid estrogens in wild fish species from different sampling sites was in the order of STP-5 > Dianchi Lake (2013) > Dianchi Lake (2010)  Dianchi Lake (2009)  field control > laboratory control, which is mainly affected by exposure concentrations. By employing risk quotient (RQ), it is found that eco-toxicological risk of steroid estrogens in Dianchi Lake catchment was in a sequence of 22 rivers > effluents of eight STPs > Dianchi Lake (2013) > Dianchi Lake (2010), and high RQs were found in EE2, which should be controlled preferentially in this catchment.  相似文献   

18.
A dynamic model for assessing the transfer of several radionuclides ((58)Co, (60)Co, (110 m)Ag, (134)Cs, (137)Cs, (54)Mn and (131)I) in a food-chain was applied on the Loire river, where 14 nuclear power plants situated on five different sites operate. The model considers the following potential exposure pathways: (i) transfer of radionuclides through the aquatic food chain and the subsequent internal exposure of humans due to ingestion of contaminated water and/or fish; (ii) use of river water for agricultural purposes (irrigation), transfer of radionuclides through the terrestrial food chain and the subsequent internal exposure of humans due to ingestion of contaminated foodstuffs; (iii) internal exposure due to inhalation of dust originating from resuspension of contaminated soil particles; (iv) external exposure from radionuclides present in the river or deposited on the river sediments or the soil. For each of the parameters introduced in this model, a probability density function, allowing further uncertainty and sensitivity analysis, was proposed. Uncertainty/sensitivity analysis were performed to: (i) compare calculations to empirical data; (ii) determine a confidence interval for the mean annual dose to critical groups; and (iii) identify the parameters responsible for the uncertainty and subsequent research priorities.  相似文献   

19.
Human milk is the most important form of nourishment for newborn children. Its consumption is strongly recommended by health authorities also for other important advantages. Unfortunately, in the last three decades a great number of investigations have shown the occurrence of several environmental contaminants in human milk, especially those with lipophilic properties. This study investigates the presence of nonylphenol, octylphenol (OP), nonylphenol monoethoxylate (NP1EO) and two octylphenol ethoxylates (OPEOs) (namely OP1EO and OP2EO), in human breast milk of Italian women. NP was the contaminant found at the highest levels with mean concentrations of 32 ng/mL, about two orders of magnitude higher than OP (0.08 ng/mL), OP1EO (0.07 ng/mL) and OP2EO (0.16 ng/mL). In the group of study a positive correlation among fish consumption and levels of NP in the milk was observed, in accordance with the evidence that seafood represents one of the most important sources of exposure to this group of contaminants in Italy. On the basis of the concentrations found in the breast milk samples, a maximum NP daily intake of 3.94 mug/kg/day can be calculated, which is close to the Tolerable Daily Intake (TDI) of 5 mug/kg body weight (bw) proposed by the Danish Institute of Safety and Toxicology. In the cases of OP no TDI is available, but its intake is at least six orders of magnitude lower than the NOAEL of 10 mg/kg/day derived from a two generation study on rats.  相似文献   

20.
The presence of linear alkylbenzene sulfonates (LAS) and their degradation intermediates, sulfophenylcarboxylic acids (SPCs), with concentrations up to 100 ppb has been found in surface waters taken from the estuary of the river Guadalete (Cádiz, SW of Spain). Higher concentrations were found at the sampling site located adjacent to the discharge outlet of a wastewater treatment plant (WWTP). The concentrations decreased downstream to a few ppb as a result of dilution, sorption, and degradation processes, which were taking place along the estuary. Once the presence of both xenobiotics was confirmed in the environment, an in vivo assay was conducted to study their biotransformation and effects in the benthic fish Solea senegalensis. A flow-through system was employed, consisting of an exposure phase (120 h) with environmental levels of the surfactant (200, 500 and 800 microg/L of 2?C(10)LAS), followed by a depuration stage (72 h). The generation of SPCs has been quantified during these phases in both water and fish, with LAS biotransformation shown in all cases. The antioxidant enzymes catalase (CAT), glutathione peroxidase (GPX), glutathione reductase (GR), the phase II enzyme glutathione S-transferase (GST), and the phase III acid and alkaline phosphatases (AcP, ALP) were also estimated and utilized as biomarkers.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号