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Various measures of plants, soils, and invertebrates were described for a reference set of tidal coastal wetlands in Southern New England in order to provide a framework for assessing the condition of other similar wetlands in the region. The condition of the ten coastal wetlands with similar hydrology and geomorphology were ranked from least altered to highly altered using a combination of statistical methods and best professional judgment. Variables of plants, soils, and invertebrates were examined separately using principal component analysis to reduce the multidimensional variables to principal component scores. The first principal component scores of each set of variables (i.e., plants, soil, invertebrates) significantly (p?<?0.05) correlated with both residential land use and watershed nitrogen (N) loads. Using cumulative frequency diagrams, the first principal component scores of each plant, soil, and invertebrate data set were plotted, and natural breaks and best professional judgment were used to rank the first principal component scores among the sites. We weighted all three ranked components equally and calculated an overall salt marsh condition index by summing the three ranks and then transforming the index to a 0–1 scale. The overall salt marsh condition index for the reference coastal wetland set significantly correlated with the residential land use (R?=???0.87, p?=?0.001) and watershed N loads (R?=???0.86, p?=?0.001). Overall, condition deteriorated in salt marshes and their associated discharge streams when subjected to increasing watershed residential land use and N loads.  相似文献   

4.
A study was performed in Del Rey Lagoon, City of Los Angeles, to determine if the lagoon was as a source or sink for fecal indicator bacteria (FIB: total coliforms, Escherichia coli, enterococci) and to screen for the presence of other potentially pathogenic bacteria. The lagoon receives tidal flows from the adjacent Ballona Estuary whose water usually is contaminated with FIB originating from the highly urbanized Ballona Creek Watershed. During 16 sampling events from February 2008 through March 2009, replicate water samples (n?=?3) were collected 1 h prior to the high tide and 1 h prior to the following low tide. FIB concentrations were measured by the defined substrate method (IDEXX, Westbrook, Me) followed by culturing of bacterial isolates sampled from positive IDEXX Quanti-Tray wells and were identified using the Vitek 2 Compact (bioMérieux, Durham, NC). Mean concentrations of FIB often differed by an order of magnitude from flood to ebb flow conditions. The lagoon tended to act as a sink for total coliforms based on the ratio of mean flood to ebb densities (R F/E) >1.0 during 56 % of the sampling events and during ebb flows, as a source for E. coli and enterococci (R F/E <1.69 % of events). Approximately 54 species were identified from 277 isolates cultured from the IDEXX Quanti-Trays. Of these, 54 % were species known to include pathogenic strains that can be naturally occurring, introduced in runoff, or originated from other sources. Diversity and cluster analyses indicated a dynamic assemblage that changes in species composition with day-to-day fluctuations as well as tidal action. The concept of monitoring the lagoon and estuary as a sentinel habitat for pathogenic assemblages is discussed.  相似文献   

5.
目的在于比较固定底物酶底物法与多管发酵法用于水中粪大肠菌群(耐热大肠菌群)的检测,使用科立得TM(Colilert(R))试刺和传统方法检测地表水、水源水及污水水样,比较固定底物酶底物法与多管发酵法用于水中粪大肠菌群(耐热大肠菌群)检测结果的一致性.结果表明,固定底物酶底物法与多管发酵法用于水中粪大肠菌群(耐热大肠菌群)检测结果具有一致性,固定底物酶底物法可以用作评价水质微生物污染的标准方法.  相似文献   

6.
The labile species of Ni, Cu, Zn, Cd, and Pb in the Tama River, an urban river in Tokyo, Japan, were measured using diffusive gradients in thin films (DGT) method under dry and wet weather conditions, and the results were compared with total dissolved concentrations in hourly samples collected in parallel. A total of 10 DGT deployments were made and 251 hourly samples were collected during 2 rounds of sampling, conducted between August and October, 2006. Two types of diffusive gradients in thin films (DGT) devices-DGT-RG for labile inorganic and DGT-APA for total (inorganic and organic) labile species-were applied throughout the samplings. The proportions of metals measured by DGT, compared with the dissolved metal concentrations (filtered using a membrane of 0.5 microm pore size), were 38 +/- 5% (RG) and 45 +/- 8% (APA) for Ni and 45 +/- 22% (RG) and 53 +/- 23% (APA) for Zn. No labile Cu was detected throughout the sampling; Cu was assumed to be in stable complexed forms. Labile Pb was detected in 3 out of 10 deployments only; the rest were lower than the detection limit. Dissolved and labile Cd concentrations were below the detection limits. Three rain events encountered during the sampling periods were evaluated. Rains brought considerably higher loads of metals in dissolved form, and DGT measurements indicated that labile metal loads also increased. Selected DGT measurements were compared with the WHAM 6 speciation model and found to be similar to the model-computed results.  相似文献   

7.
With the aim of knowing Hg distribution in selected tissues of myliobatid stingrays and assessing health risk to Mexican population, Hg concentration was determined in the muscle and liver of four ray species. Total Hg levels were determined by cold vapor atomic absorption spectrophotometry. With respect to the muscle, devil rays (Mobula spp.) showed lower Hg levels (<0.22 μg g?1) than Rhinoptera steindachneri (0.37?±?0.25 μg g-1 wet weight). In the case of the liver, the highest Hg concentration was found in Mobula japanica (0.22?±?0.01 μg g?1). Hg levels in the muscle and liver varied according to the species; in some case, the liver accumulated more Hg than the muscle and the opposite pattern in other cases. R. steindachneri showed a significant difference between both tissues. No significant differences of Hg levels between males and females and between juveniles and adult specimens of R. steindachneri were found. Positive correlation between Hg concentrations and disc width and total weight was not significant for R. steindachneri (Rs?<?0.36, p?>?0.05). Batoids showed Hg values below the Mexican (NOM-027-SSA1-1993) limits (1.0 μg g?1) in fishes for human consumption. The species with the highest potential of Hg transfer to human population is R. steindachneri; however, an adult (70 kg) could consume approximately 943 g per week without representing a health risk. Nevertheless, further and continuous monitoring is needed since batoids support an important fishery in Mexican waters, being a food resource and income to coastal communities.  相似文献   

8.
Chemical (polycyclic aromatic hydrocarbon - PAH and heavy metal) levels in stormwater and sediment samples collected from the London Orbital (M25) motorway drainage dry detention pond at Oxted, Surrey, UK were determined. Such chemicals are derived from vehicular combustion products and the wear and tear materials deposited onto the motorway surface. Gas chromatography-mass spectrometry (GC-MS) was used for the qualitative and quantitative determination of 16 USEPA priority PAHs in motorway drainage sediments. The GC-MS method, incorporating a solid phase extraction step, provides detection limits ranging from 0.17 to 0.41 mg kg(-1)(dry weight). Almost all of the 16 USEPA listed PAHs were detected. Phenanthrene, fluoranthene, pyrene, benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(a)pyrene and benzo(g,h,i)perylene (PAH numbers 5, 7, 8, 9, 10, 11, 13 and 16) were among the PAHs found at "higher" levels (ranging from 0.3-10.2 mg kg(-1), dry weight) in the sediment samples. PAH levels show little change along the motorway drainage silt trap (facility for reducing the levels of suspended particulate matter in the stormwater). PAH concentrations are considerably higher in the dry detention pond outflow interceptor. Statistical analysis showed that significant correlation coefficients (based on a t-test at the 95% confidence interval) were obtained between those PAHs found at high concentrations over all of the sampling sites. Several PAHs were dispersed beyond the treatment facility and accumulation in the sediment of the deer park resulted in levels ranging from 0.3-1.6 mg kg(-1), dry weight. These PAHs found beyond the treatment facility (in the local farm deer park) may contribute a serious health threat to farm animals or even fish in the aquatic environment. Heavy metal levels (V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Cd, Sb and Pb) of the drainage stormwater and sediments were determined by inductively coupled plasma mass spectrometry (ICP-MS), with quality control evaluation using two certified reference materials. Typical detection limits were found to be below 0.1 [micro sign]g l(-1) for stormwater and 0.005 mg kg(-1) for acid digested sediments. Raised heavy metal levels were found throughout the dry detention pond facility and only decrease when the stormwater is diluted following discharge into the river Eden. Statistical analysis also confirms that some significant correlations exist between various heavy metals and PAHs. However, no overall conclusive trend is found indicating that a particular PAH is deposited in sediment relative to a specific heavy metal/s. These results raise some serious concerns about the dispersion and accumulation of chemicals in the sediments of motorway stormwater drainage systems and the need for maintenance and clean-up of contaminated material from such systems.  相似文献   

9.
With the aim of giving an overview on concentration and distribution of Cd, Cu, and Pb in fish from the coasts of Sinaloa state (SE Gulf of California), specimens with different feeding habits were collected in five locations. Sampling occurred between June 2003 and March 2004. Metal analyses on fish tissues were made by graphite furnace (Cd, Pb) and flame (Cu) atomic absorption spectrophotometry. Metal concentrations in tissues of carnivorous fish were grouped together and compared with corresponding concentrations in non-carnivorous fish; Cu and Pb levels were significantly (p?<?0.05) higher in liver of non-carnivorous species. Though no samples exceeded the maximum level set in international legislation for fish, from the perspective of the public health and considering the legal limits of fishery products for human consumption, Cu concentrations were exceeded (in tissues different from muscle) in four carnivorous and five non-carnivorous species according to the Australian legislation. In the case of Cd, two carnivorous species (Pomadasys leuciscus and Caulolatilus princeps) and one non-carnivorous species (Mugil cephalus), showed concentrations over the maximum level of 2 μg g???1 dry weight considered in the Mexican legislation. Considering average amounts of fish consumption in Mexico, daily mineral intake (DMI) values for Cu and percentage weekly intake (PWI) of Cd and Pb were estimated; none of the analyzed metals in edible portion of analyzed fish could be detrimental to humans.  相似文献   

10.
Chromium (VI) [Cr (VI)] biosorption by four resistant autochthonous bacterial strains was investigated to determine their potential for use in sustainable marine water-pollution control. Maximum exchange between Cr (VI) ions and protons on the cells surfaces were at 30–35 °C, pH?2.0 and 350–450 mg/L. The bacterial strains effectively removed 79.0–90.5 % Cr (VI) ions from solution. Furthermore, 85.3–93.0 % of Cr (VI) ions were regenerated from the biomasses, and 83.4–91.7 % of the metal was adsorbed when the biomasses was reused. Langmuir isotherm performed better than Freundlich isotherm, depicting that Cr (VI) affinity was in the sequence Rhodococcus sp. AL03Ni?>?Burkholderia cepacia AL96Co?>?Corynebacterium kutscheri FL108Hg?>?Pseudomonas aeruginosa CA207Ni. Biosorption isotherms confirmed that Rhodococcus sp. AL03Ni was a better biosorbent with a maximum uptake of 107.46 mg of Cr (VI) per g (dry weight) of biomass. The results highlight the high potential of the organisms for bacteria-based detoxification of Cr (VI) via biosorption.  相似文献   

11.
The objective of this paper is to study the hydrological characteristics and origin of the hydrogen sulphide spring water from the Split spa in Southern Croatia in 1987, 1988 and 2003. This paper presents the results of monitoring the content of chlorides and hydrogen sulphide as well as the temperature of the hydrogen sulphide spring water. Since the hydrogen sulphide content during the dry periods significantly differs from the hydrogen sulphide content during rainy periods, this paper also compares the results obtained for those two periods. Under the influence of great quantities of rainfall during cold periods (winter and the beginning of spring) the ratio between seawater and surface water changes and thus the reduction of chlorides and other minerals occurs. The lowered temperature also reduces hydrogen sulphide which can disappear completely. The concentration of 12‰ chlorides (76–94.4% days/year) and 12 mg/L hydrogen sulphide (66.7–88.9% days/year) has been taken as a limit value between water with a normal typical content and water in cold rainy periods. According to the monitoring results it can be concluded that hydrogen sulphide spring water consists of seawater and hydrogencarbonate surface water with a fairly constant content during dry periods while the hydrogencarbonate content increases during rainy periods.  相似文献   

12.
The aim of this study was to monitor the heavy metal contents and fecal pollution in Tapes decussatus (carpet shell clam) from Izmir Bay (Eastern Aegean). Bivalve mollusks were sampled on January, March, July, and October 2007 in the Izmir Bay. Izmir Bay is one of the great natural bays of the Mediterranean. Concentrations of heavy metals were determined in the clams from the different seasons. Fecal coliform densities were determined to evaluate the degree of water pollution and clams’ microbiological accumulation of the classical microbial pollution indicators. The concentration of heavy metals in T. decussatus from Izmir Bay were Hg 0.044–0.13; Cd 0.026–0.24; Pb 0.38–1.2; Cr 2.3–3.7; Cu 6.4–8.4; Zn 56.0–81.8, and Ni 8.1–9.6 μg/g (dry weight). The maximum values were generally obtained in July and March except Ni. This study found that the levels of heavy metals except Cr in T. decussatus were below Spanish and European Communities legislations for shellfish as food. Microbial pollution indicators (heterotrophic bacteria and fecal coliform) were measured in T. decussatus. Maximum heterotrophic bacteria and fecal coliforms were recorded in the winter while the lowest were detected in summer.  相似文献   

13.
Sediments from the Tagus estuary (Portugal) were collected at 40 stations in July and December 2004. Total LAS concentrations ranged between 0.03 and 17.76 mg LAS.kg(-1) dry weight in July, and between 0.09 and 9.57 mg LAS.kg(-1) in December. Highest LAS concentrations were found at the upper northern part of the estuary, coincident with the localisation of an important waste water treatment station. According to the Predicted No Effect Concentration (PNEC) of 8.1 mg.kg(-1) derived for this compound, Environmental Risk Assessment (ERA) identified a hazard for the ecosystem at the station with the highest LAS concentration, and similar results are obtained by Equilibrium Partitioning Method (EPM). Nevertheless, LAS concentrations decreased significantly between samplings in the stations with the highest LAS concentrations in July, whereas increased LAS concentrations at adjacent stations were found in December. In the remaining stations, LAS concentrations were up to three orders of magnitude lower, representing no hazard for the sediment community.  相似文献   

14.
Microbial source tracking (MST) methods need to be rapid, inexpensive and accurate. Unfortunately, many MST methods provide a wealth of information that is difficult to interpret by the regulators who use this information to make decisions. This paper describes the use of classification tree analysis to interpret the results of a MST method based on fatty acid methyl ester (FAME) profiles of Escherichia coli isolates, and to present results in a format readily interpretable by water quality managers. Raw sewage E. coli isolates and animal E. coli isolates from cow, dog, gull, and horse were isolated and their FAME profiles collected. Correct classification rates determined with leaveone-out cross-validation resulted in an overall low correct classification rate of 61%. A higher overall correct classification rate of 85% was obtained when the animal isolates were pooled together and compared to the raw sewage isolates. Bootstrap aggregation or adaptive resampling and combining of the FAME profile data increased correct classification rates substantially. Other MST methods may be better suited to differentiate between different fecal sources but classification tree analysis has enabled us to distinguish raw sewage from animal E. coli isolates, which previously had not been possible with other multivariate methods such as principal component analysis and cluster analysis.  相似文献   

15.
Eels are exposed to pollutants due to their unusual life cycle and are vulnerable to contamination associated with sediment due to their diet, feeding habits and territoriality. Since the 1980s, a decline in American and European eel populations has been recorded. The causes of this decline still are unknown but pollution from domestic and industrial effluents is known to be involved. Since little data is available on PCB contamination in eels from Italian waters, PCBs were measured in muscle of Anguilla anguilla captured in 2001 in two brackish ecosystems of the Mediterranean: the lagoons of Orbetello and Santa Giusta (Italy). PCBs were higher in samples from Orbetello lagoon than in those detected from Santa Giusta lagoon (P < 0.05). Congener and isomer analyses indicated Aroclor 1260 as a likely source of PCBs in the Orbetello and Santa Giusta samples. Only the toxic equivalents (TEQs) of mono-ortho PCBs were calculated.  相似文献   

16.
Selected toxic and essential metals (mercury, Hg; cadmium, Cd; and zinc, Zn) were determined in the liver and in the kidney collected from 13 dolphins (Stenella coeruleoalba and Tursiops truncatus) stranded along the southern coasts of Italy from 1991 to 1999. Liver samples were also analysed for their methyl mercury (MeHg) and selenium (Se) contents. For subcellular fractionation, liver and kidney samples were homogenized in Tris-HCl buffer; after centrifugation, the supernatant (cytosol) was separated from pellets (insoluble fraction), heated at 80 degrees C for 10 min and centrifuged in order to separate the precipitate containing the thermolabile high molecular weight proteins. The cytosol heat-stable fraction, including metallothionein-like proteins (MTLPs), was then purified by gel filtration chromatography on Sephadex G-75 column. The three subcellular fractions collected (insoluble fraction, thermolabile fraction and purified heat-stable fraction) were analysed for their Hg, Cd and Zn contents. The analytical results confirm previous similar studies on toothed whales in showing that: (1) in the liver, as well as in the kidney, Hg was mainly found in the insoluble fraction, therefore, metallothioneins seem to have no role in the Hg detoxification; (2) in the liver, the molar ratio between Se and inorganic Hg was very close to 1; this suggests that the final compound of MeHg detoxification could be HgSe (tiemannite); (3) in almost all the samples, Cd and Zn were detected in the purified heat-stable fraction (including MTLPs). The mechanism of Cd detoxification and Zn homeostasis is also discussed.  相似文献   

17.
The main objectives of article were monitor the metal concentrations of cadmium, lead, copper, zinc, cobalt, and iron, in the feather of shorebirds species, Western Reef Heron (Egretta gularis) and Siberian Gull (Larus heuglini) from Hara Biosphere Reserve of Southern Iran; and identify any relationships between species. Assaying heavy metals by using Shimadzu AA 680 flame atomic absorption spectrophotometer, the results were given as micrograms per gram dry weight. The concentrations of heavy metal were found to follow the order of iron>zinc>copper>lead>cadmium>cobalt for E. gularis and of iron>zinc>lead>copper>cadmium>cobalt for L. heuglini. Also, they showed that the cadmium, copper, and cobalt concentrations were higher in females than in the males, while the lead concentration for E. gularis and L. heuglini was higher in males. The cadmium concentration means they were measured as1.16 and 1.37 μg/g for E. gularis and L. heuglini, respectively, whereas the lead concentration means 7.04 and 5.48 μg/g for E. gularis and L. heuglini, respectively. The concentrations of nonessential trace elements in E. gularis and L. heuglini were generally comparable to values reported in other studies. The average levels of lead we observed in these birds were greater than 5 μg/g dry weight in the feather that is known to be associated with adverse behavioral or reproductive effects. Data analysis showed that there was a positive correlation between copper and zinc (P?相似文献   

18.
In this study, we examined the bioavailability of arsenic through the mangrove oyster Crassostrea corteziensis sampled from seven coastal lagoons in SE Gulf of California during the rainy and dry seasons. As concentrations in soft tissue of oysters C. corteziensis fluctuated between 5.2 and 11.6 μg/g on dry weight; organisms from the control site presented the lowest As concentrations in the two sampling seasons. As speciation was evaluated in selected samples and indicated that arsenobetaine was the major arseno-compound accounting for 53.5–74.7 % of total As. Lower percentage contributions were obtained for nonextractable As (9.7–25.5 %) and other molecules such as arsenocholine and methyl-arsonate (<5 %). Inorganic As was detectable in only two samples, at concentrations lower than 0.1 μg/g. These As data are the first generated in NW Mexico and indicate that C. corteziensis is safe for human consumption in terms of arseno-compounds. It is evident that As bioavailability in these lagoons is low.  相似文献   

19.
Spatial and temporal variability of Cd, Cu, Cr, Ni, Zn, Fe and Mn and metallothionein (MT) concentrations were determined in mussels Mytilus galloprovincialis from Elefsis bay (Saronikos gulf, Greece). Higher concentrations of both metal concentrations and MTs were recorded in mussels inhabiting industrial locations (steelworks and shipyard), indicating a markedly higher metal bioavailability. However at these sites, located at the eastern part of the bay, mussel metal concentrations were not always correlated with both seawater metal concentrations and MTs possibly due to different time scales of integration of the metal sources into mussels and/or the participation of other metal regulatory mechanisms except MT induction. The pattern of the temporal variation of mussel metal concentrations and the MT levels was similar among stations with higher values during the winter–spring season and lower during the summer–autumn period. The inverse relationship of flesh condition index with mussel metal concentrations was attributed to the influence of mussel annual reproductive cycle.  相似文献   

20.
Sediments are an ecologically important component of the aquatic environment and may play a key role in mediating the exchange of contaminants between particulate, dissolved, and biological phases. For a comprehensive assessment of potential sediment toxicity, the use of a single species may not detect toxicant with a specific mode of action. Therefore it is advisable to carry out ecotoxicological tests on a base-set of taxa utilizing test species belonging to different trophic levels. This paper describes the ecotoxicological evaluation of marine sediments from seven sites of Mar Piccolo estuary (Southern, Italy), four of them were located in the first inlet and three in the second inlet of Mar Piccolo estuary. Sediment samples from a site in Taranto Gulf were used as control sediment. Dunaliella tertiolecta, Tigriopus fulvus, Mytilus galloprovincialis, and Corophium insidiosum, were employed to identify the quality of sediments. The integration of biological tests results showed that all sampling sites located in the first inlet of Mar Piccolo were identified as toxic, according to all tests, while the sites of second inlet were found not toxic. The results obtained in this study indicate that the use of a battery of biological tests have important implications for risk assessment in estuarine e coastal waters.  相似文献   

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