The Steubenville comprehensive air monitoring program (SCAMP): overview and statistical considerations

Average concentrations of particulate matter with an aerodynamic diameter less than or equal to 2.5 microm (PM2.5) in Steubenville, OH, have decreased by more than 10 microg/m3 since the landmark Harvard Six Cities Study associated the city's elevated PM2.5 concentrations with adverse health effects in the 1980s. Given the promulgation of a new National Ambient Air Quality Standard (NAAQS) for PM2.5 in 1997, a current assessment of PM2.5 in the Steubenville region is warranted. The Steubenville Comprehensive Air Monitoring Program (SCAMP) was conducted from 2000 through 2002 to provide such an assessment. The program included both an outdoor ambient air monitoring component and an indoor and personal air sampling component. This paper, which is the first in a series of four that will present results from the outdoor portion of SCAMP, provides an overview of the outdoor ambient air monitoring program and addresses statistical issues, most notably autocorrelation, that have been overlooked by many PM2.5 data analyses. The average PM2.5 concentration measured in Steubenville during SCAMP (18.4 microg/m3) was 3.4 microg/m3 above the annual PM2.5 NAAQS. On average, sulfate and organic material accounted for approximately 31% and 25%, respectively, of the total PM2.5 mass. Local sources contributed an estimated 4.6 microg/m3 to Steubenville's mean PM2.5 concentration. PM2.5 and each of its major ionic components were significantly correlated in space across all pairs of monitoring sites in the region, suggesting the influence of meteorology and long-range transport on regional PM2.5 concentrations. Statistically significant autocorrelation was observed among time series of PM2.5 and component data collected at daily and 1-in-4-day frequencies during SCAMP. Results of spatial analyses that accounted for autocorrelation were generally consistent with findings from previous studies that did not consider autocorrelation; however, these analyses also indicated that failure to account for autocorrelation can lead to incorrect conclusions about statistical significance.     

Impacts of Meteorological Factors on PM10: Artificial Neural Networks (ANN) and Multiple Linear Regression (MLR) Approaches

In this study, prediction capacities of multi-linear regression (MLR) and artificial neural networks (ANN) onto coarse particulate matter (PM₁₀) concentrations were investigated. Different meteorological factors on particulate pollution were chosen for operating variables in the model analyses. Two different regions (urban and industrial) were identified in the region of Kocaeli, Turkey. All data sets were obtained from air quality monitoring network of the Ministry of Environment and Urban Planning, and 120 data sets were used in the MLR and ANN models. Regression equations explained the effects of the meteorological factors in MLR analyses. In the ANN model, backpropagation network with two hidden layers has achieved the best prediction efficiency. Determination coefficients and error values were examined for each model. ANN models displayed more accurate results compared to MLR.     

微生物絮凝剂产生菌的筛选及其絮凝特性

采用常规的微生物学方法,从垃圾渗滤液中筛选到一株高效微生物絮凝剂产生菌LB1,根据其形态学和生理生化特征初步鉴定该菌株属于假单胞菌属,命名为Pseudonomas sp. LB1。LB1所产微生物絮凝剂的絮凝特性的研究结果表明,LB1的最佳产絮凝时间为96 h,所产絮凝活性物质主要是其生长过程中的胞外分泌物和细胞生长后期的次级代谢产物,菌体细胞本身具有一定的助凝作用。LB1所产絮凝剂最佳加样量为3％（体积分数V/V）;对pH的适应范围较宽,在4～10之间具有较高的絮凝活性,均大于75％;温度为25℃时絮凝率为86.3％,在25～60℃之间,絮凝率基本保持稳定;LB1所产絮凝剂对几种废水具有较好的絮凝效果。     

Capillary electrophoresis finger print technique (CE-SSCP): an alternative tool for the monitoring activities of HAB species in Baja California Sur Costal

In Mexican waters, there is no a formal and well-established monitoring program of harmful algal blooms (HAB) events. Until now, most of the work has been focused on the characterization of organisms present in certain communities. Therefore, the development of new techniques for the rapid detection of HAB species is necessary. Capillary electrophoresis finger print technique (CE-SSCP) is a fingerprinting technique based on the identification of different conformers dependent of its base composition. This technique, coupled with capillary electrophoresis, has been used to compare and identify different conformers. The aim of this study was to determine if CE-SSCP analysis of ribosomal RNA (rRNA) gene fragments could be used for a rapid identification of toxic and harmful HAB species to improve monitoring activities along the coasts of Baja California Sur, Mexico.Three different highly variable regions of the 18S and 28S rRNA genes were chosen and their suitability for the discrimination of different dinoflagellate species was assessed by CE-SSCP.The CE-SSCP results obtained for the LSU D7 fragment has demonstrated that this technique with this gene region could be useful for the identification of the ten dinoflagellates species of different genera.We have shown that this method can be used to discriminate species and the next step will be to apply it to natural samples to achieve our goal of molecular monitoring for toxic algae in Mexican waters. This strategy will offer an option to improve an early warning system of HAB events for coastal BCS, allowing the possible implementation of mitigation strategies. A monitoring program of HAB species using molecular methods will permit the analysis of several samples in a short period of time, without the pressure of counting with a taxonomic expert in phytoplankton taxonomy.     

Biomarkers of carcinogenic contaminants in baltic flounder (Platichthys flesus)

In order to study effects of environmental contamination, a suite of biomarkers were measured over the period 1996 to 1999 in livers of flounder (Platichthys flesus) from two urban embayments and one non-urban reference site of the Gulf of Finland in the vicinity of Tallinn, Estonia. Total cytochrorne P450 (CYP) level, aryl hydrocarbon hydroxylase (AHH), 5-amino-levulinic acid synthetase (ALA-S), and heme synthetase (HEM-S) activities were quantified by means of spectrophotometry. These data were compared to results obtained in 1994 for the same biomarkers at one of the urban embayments and the non-urban site, as measured by the same protocols. For the flounder collected from the non-urban site, changes occurred in AHH activity and the total CYP level, which were significantly lower in 1996 and 1999 compared with 1994 (p< 0.05). Activity of ALA-S de-creased slightly over this same period. The activity of HEM-S increased between 1996 and 1999. In the urban site first investigated in 1994, the activities of AHH and ALA-S, as well as the total level of CYP in flounder liver were significantly higher compared with 1999 (p< 0.05). HEM-S activities did not show any significant changes over this time period. AHH activities of flounder collected in another urban site decreased slightly between 1996 and 1999, in contrast to data on the total CYP level which diminished drastically over these years (p< 0.05). Activities of HEM-S increased significantly (p< 0.05) during the period investigated, while activities of ALA-S remained unchanged. These findings suggest that contamination of the marine environments by PAHs has gone down everywhere in the Tallinn area during the last 3 to 5 years. However, the results indicate that the area is still contaminated, as indicated by elevated heme synthesis enzymes and the total CYP content, and that monitoring of contaminants and their effects should be continued in this region.     

A Monitoring Network Design Procedure for Three-Dimensional (3D) Groundwater Contaminant Source Identification

Finding the location and concentration of contaminant sources is an important step in groundwater remediation and management. This discovery typically requires the solution of an inverse problem. This inverse problem can be formulated as an optimization problem where the objective function is the sum of the square of the errors between the observed and predicted values of contaminant concentration at the observation wells. Studies show that the source identification accuracy is dependent on the observation locations (i.e., network geometry) and frequency of sampling; thus, finding a set of optimal monitoring well locations is very important for characterizing the source. The objective of this study is to propose a sensitivity-based method for optimal placement of monitoring wells by incorporating two uncertainties: the source location and hydraulic conductivity. An optimality metric called D-optimality in combination with a distance metric, which tends to make monitoring locations as far apart from each other as possible, is developed for finding optimal monitoring well locations for source identification. To address uncertainty in hydraulic conductivity, an integration method of multiple well designs is proposed based on multiple hydraulic conductivity realizations. Genetic algorithm is used as a search technique for this discrete combinatorial optimization problem. This procedure was applied to a hypothetical problem based on the well-known Borden Site data in Canada. The results show that the criterion-based selection proposed in this paper provides improved source identification performance when compared to uniformly distributed placement of wells.     

Concentration of Organochlorine Pollutants in Surface Waters of the Central European Biosphere Reserve Krivoklatsko (8 pp)

Background, Aim and Scope The article is focused on dioxin, furan, PCB and organochlorine pesticide monitoring in the surface waters of the Central European, protected natural reserve Krivoklatsko, under the UNESCO programme Man and Biosphere. Persistent compounds are presently transported via different means throughout the entire world. This contamination varies significantly between sites. This raises the question of what constitutes the naturally occurring background levels of POPs in natural, unpolluted areas, but which are close to industrialised regions. Information of real background POP contamination can be of high value for risk assessment management of those sites evidently polluted and for the defining of de-contamination limits. Preserved areas should not be seen as isolated regions in which the impacts of human activities and natural factors are either unexpected or overlooked. Every ambient region, even those protected by a law or other means, are still closely connected to neighbouring human developed and impacted areas, and are therefore subject to this anthropogenic contamination. These areas adjacent to natural reserves are sources of diverse substances, via entry of air, water, soil and/or biota. After an extended period of industrial activities, organochlorine pollutants, even those emitted in trace concentrations have reached detectable levels. For future research and for the assessment of environmental changes, present levels of contamination would be of high importance. This work publishes data of the contamination with organochlorine pollutants of this natural region, where biodiversity and ecological functions are of the highest order. Materials and Methods: Semipermeable membrane devices (SPMDs) were utilised as the sampling system. SPMDs were deployed in two small creeks and one water reservoir selected in the central part of the Krivoklatsko Natural Reserve, where it could be expected that any possible contamination by POPs would be lowest. The exposed SPMDs were analysed both for chemical contents of POPs and for toxicity properties. The chemical analyses of dibenzo-dioxins, dibenzo-furans, PCBs and OCPs were analysed by GC/MS/MS on GCQ or PolarisQ (Thermoquest). Toxicity bioassays were performed on the alga Desmodesmus subspicatus, bacteria Vibrio fischeri and crustacean Daphnia magna. All toxicity data were expressed as the effective volume Vtox. Vtox is a toxicity parameter, the determination of which is independent of SPMD deployment time and pre-treatment dilution (unlike, for example, the EC50 of the SPMD extract). Results: The following chemical parameters were monitored: 1) tetra, penta, hexa and hepta dibenzo-p-dioxins and furans; 2) all those detectable from tri- through deca-polychloriated biphenyls (PCBs) and 3) a group of organochlorine pesticides: hexachlorobenzene and isomers of hexachlorocyclohexane, DDE, DDD and DDT. The concentrations of dioxins and furans on the assessed sites varied from under detection levels up to 7 pg.l-1; PCBs were detected in a sum concentration up to 2.8 ng.l-1; and organochlorine pesticides up to 346 pg.l-1. The responses of bioassays used were very low, with the values obtained for Vtox being under 0.03 l/d. Discussion: Toxicity testing showed no toxicity responses, demonstrating that the system used is in coherence with the ecological status of the assessed sites. Values of Vtox were under the critical value – showing no toxicity. The PCA of chemical analysis data and toxicity responses resulted in no correlations between these two groups of parameters. This demonstrated that the present level of contamination has had no direct adverse effects on the biota. Conclusions: The concentration values of six EPA-listed, toxic dioxins and sums of tetra-hepta dioxins; nine EPA toxic dibenzofurans and the sums of tetra-hepta bibenzofurans are presented together with all tri-deka PCBs and organochlorine pesticides (alfa-, beta-, gama-, delta-HCH, HCB, opDDE, ppDDE, opDDD, ppDDD, opDDT, ppDDT). These values represent possible current regional natural background values of these substances monitored within the Central European region, with no recorded adverse effects on the freshwater ecosystem (up until the present time). Recommendations and Perspectives: Assessment of dioxins, furans and other organochlorine compounds within natural reserves can be important for the monitoring of human-induced impacts on preserved areas. No systematic monitoring of these substances in areas not directly affected by industry has generally been realised. There is a paucity of data of the presence of any of these substances within natural regions. Further monitoring of contamination of both soil and biota by dioxins and furans in preserve regions is needed and can be used for future monitoring of man-made activities and/or accidents. Semipermeable membrane devices proved to be a very good sampling system for the monitoring of trace concentrations of ambient organochlorine compounds. Toxicity evaluation using the Vtox concept demonstrated that those localities assessed expressed no toxicity.     

Detection of feral GT73 transgenic oilseed rape (Brassica napus) along railway lines on entry routes to oilseed factories in Switzerland

To obtain a reference status prior to cultivation of genetically modified oilseed rape (OSR, Brassica napus L.) in Switzerland, the occurrence of feral OSR was monitored along transportation routes and at processing sites. The focus was set on the detection of (transgenic) OSR along railway lines from the Swiss borders with Italy and France to the respective oilseed processing factories in Southern and Northern Switzerland (Ticino and region of Basel). A monitoring concept was developed to identify sites of largest risk of escape of genetically modified plants into the environment in Switzerland. Transport spillage of OSR seeds from railway goods cars particularly at risk hot spots such as switch yards and (un)loading points but also incidental and continuous spillage were considered. All OSR plants, including their hybridization partners which were collected at the respective monitoring sites were analyzed for the presence of transgenes by real-time PCR. On sampling lengths each of 4.2 and 5.7 km, respectively, 461 and 1,574 plants were sampled in Ticino and the region of Basel. OSR plants were found most frequently along the routes to the oilseed facilities, and in larger amounts on risk hot spots compared to sites of random sampling. At three locations in both monitored regions, transgenic B. napus line GT73 carrying the glyphosate resistance transgenes gox and CP4 epsps were detected (Ticino, 22 plants; in the region of Basel, 159).     

Comparing estimates of fugitive landfill methane emissions using inverse plume modeling obtained with Surface Emission Monitoring (SEM), Drone Emission Monitoring (DEM), and Downwind Plume Emission Monitoring (DWPEM)

ABSTRACT

As part of the global effort to quantify and manage anthropogenic greenhouse gas emissions, there is considerable interest in quantifying methane emissions in municipal solid waste landfills. A variety of analytical and experimental methods are currently in use for this task. In this paper, an optimization-based estimation method is employed to assess fugitive landfill methane emissions. The method combines inverse plume modeling with ambient air methane concentration measurements. Three different measurement approaches are tested and compared. The method is combined with surface emission monitoring (SEM), above ground drone emission monitoring (DEM), and downwind plume emission monitoring (DWPEM). The methodology is first trialed and validated using synthetic datasets in a hand-generated case study. A field study is also presented where SEM, DEM and DWPEM are tested and compared. Methane flux during two-days measurement campaign was estimated to be between 228 and 350 g/s depending on the type of measurements used. Compared to SEM, using unmanned aerial systems (UAS) allows for a rapid and comprehensive coverage of the site. However, as showed through this work, advancement of DEM-based methane sampling is governed by the advances that could be made in UAS-compatible measurement instrumentations. Downwind plume emission monitoring led to a smaller estimated flux compared with SEM and DEM without information about positions of major leak points in the landfill. Even though, the method is simple and rapid for landfill methane screening. Finally, the optimization-based methodology originally developed for SEM, shows promising results when it is combined with the drone-based collected data and downwind concentration measurements. The studied cases also discovered the limitations of the studied sampling strategies which is exploited to identify improvement strategies and recommendations for a more efficient assessment of fugitive landfill methane emissions.

Implications: Fugitive landfill methane emission estimation is tackled in the present study. An optimization-based method combined with inverse plume modeling is employed to treat data from surface emission monitoring, drone-based emission monitoring and downwind plume emission monitoring. The study helped revealing the advantages and the limitations of the studied sampling strategies. Recommendations for an efficient assessment of landfill methane emissions are formulated. The method trialed in this study for fugitive landfill methane emission could also be appropriate for rapid screening of analogous greenhouse gas emission hotspots.     

The Steubenville Comprehensive Air Monitoring Program (SCAMP): Overview and Statistical Considerations

Abstract

Average concentrations of particulate matter with an aerodynamic diameter less than or equal to 2.5 μm (PM_2.5) in Steubenville, OH, have decreased by more than 10 μg/m³ since the landmark Harvard Six Cities Study¹ associated the city’s elevated PM_2.5 concentrations with adverse health effects in the 1980s. Given the promulgation of a new National Ambient Air Quality Standard (NAAQS) for PM_2.5 in 1997, a current assessment of PM_2.5 in the Steubenville region is warranted. The Steubenville Comprehensive Air Monitoring Program (SCAMP) was conducted from 2000 through 2002 to provide such an assessment. The program included both an outdoor ambient air monitoring component and an indoor and personal air sampling component. This paper, which is the first in a series of four that will present results from the outdoor portion of SCAMP, provides an overview of the outdoor ambient air monitoring program and addresses statistical issues, most notably autocorrelation, that have been overlooked by many PM_2.5 data analyses. The average PM_2.5 concentration measured in Steubenville during SCAMP (18.4 μg/m³) was 3.4g/m³ above the annual PM_2.5 NAAQS. On average, sulfate and organic material accounted for ～31% and 25%, respectively, of the total PM_2.5 mass. Local sources contributed an estimated 4.6 μg/m³ to Steubenville’s mean PM_2.5 concentration. PM_2.5 and each of its major ionic components were significantly correlated in space across all pairs of monitoring sites in the region, suggesting the influence of meteorology and long-range transport on regional PM_2.5 concentrations. Statistically significant autocorrelation was observed among time series of PM_2.5 and component data collected at daily and 1-in-4-day frequencies during SCAMP. Results of spatial analyses that accounted for autocorrelation were generally consistent with findings from previous studies that did not consider autocorrelation; however, these analyses also indicated that failure to account for autocorrelation can lead to incorrect conclusions about statistical significance.     

Molecular cloning and expression of novel metallothionein (MT) gene in the polychaete Perinereis nuntia exposed to metals

To report a novel metallothionein (MT) gene and evaluate its potency as a biomarker, we clone this MT gene and measured the expression levels in the metal-exposed polychaete Perinereis nuntia. Accumulated metal contents and metallothionein-like proteins (MTLPs), which have been recognized as potential biomarkers, were compared with the relative mRNA expressions of the MT gene of P. nuntia (Pn-MT). In addition, the metal-binding affinity was estimated by recombinant Pn-MT protein. Pn-MT having high cysteine residues with three metal response elements in the promoter region closely clusters with those of other invertebrates. The accumulation patterns of metals were dependent on the exposure times in lead (Pb), cadmium (Cd), and copper (Cu) exposure. Particularly, both MTLP levels and relative mRNA expressions of MT were increased with accumulated metal contents and exposure time in P. nuntia exposed to Pb and Cd. There was no significant modulation of the Pn-MT gene in polychaetes exposed to Zn and As. However, the metal-binding ability of the recombinant Pn-MT protein provides a clear evidence for a high affinity of MT to several metal elements. These results suggest that Pn-MT would play an important role in the detoxification and/or sequestration of specific metals (e.g., Pb and Cd) in P. nuntia and have potential as a molecular biomarker in the monitoring of the marine environment using a polychaete.     

Anaerobic treatment of poultry mortalities in a modified LB-UASB system

The efficiency of a modified LB-UASB system in treating poultry mortalities was tested. The anaerobic digestion system consisted of an upflow anaerobic sludge blanket (UASB) and three leachbeds (LB). The LBs were batch-loaded with mortality to be treated. The LBs were sequentially connected to the UASB, one at a time. Leachate from a connected LB was fed to the UASB while effluent from the UASB overflowed to the LB to form a closed loop. When the concentrations of leachate from the first LB became so low that it could no longer support accelerated methanogenesis in the UASB, it was replaced by a second LB containing a new batch of mortality. Concentrated leachate from the second LB allowed the UASB to continue operation at higher loading rates (LR), thus, alleviating the problems of lengthy LR build-up and idling time. Meanwhile, the off-lined LB continued to mature independently. The UASB was connected to a third LB when the second LB entered accelerated methanogenesis phase. Operation of the first LB was stopped when CH4 production rate from it became marginal. The remaining solids material was replaced by a new batch of mortality to start the second cycle. The first cycle was completed when fermentation in the third LB was ended. The modified LB-UASB system performed significantly better than the original system. It took an average of only 86 days to treat one batch of mortality, yet, the methane yield was about 40% higher. The average methane yield was 0.28 m3 (kg wet weight)-1. Strategies to optimize system performances are discussed.     

Seasonal variation of pharmaceutically active compounds in surface (Tagus River) and tap water (Central Spain)

Numerous studies have shown the presence of pharmaceutically active compounds (PhACs) in different environmental compartments, for example, in surface water or wastewater ranging from nanograms per litre to micrograms per litre. Likewise, some recent studies have pointed to seasonal variability, thus indicating that PhAcs concentrations in the aquatic environment may depend on the time of year. This work intended to find out (1) whether Tagus fluvial and drinking water were polluted with different groups of PhACs and (2) if their concentrations differed between winter and summer seasons. From the 58 substances analysed, 41 were found belonging to the main therapeutic groups. Statistical differences were seen for antibacterials, antidepressants, anxiolytics, antiepileptics, and cardiovascular drugs, with higher concentrations being detected in winter than in summer. These results might indicate that the PhACs analysed in this study undergo lower environmental degradation in winter than in summer. In order to confirm these initial results, a continuous monitoring should be performed especially on those PhACs that either because of an elevated consumption or an intrinsic chemical persistence are poorly degraded during winter months due to low temperatures and solar irradiation. It is especially important to identify which of these specific PhACs are in order to recommend their substitution by equally effective and safe substances but also environmentally friendly.     

Spatial and temporal assessment of cadmium and chromium contamination in soils in the Karditsa region (Central Greece)

Environmental Science and Pollution Research - In this work, we aimed at monitoring Cd and Cr levels in surface soils in the Karditsa region (Central Greece). Soil samples were obtained throughout...     

Three-dimensional simulation of reservoir temperature and pollutant transport by the lattice Boltzmann method

Predicting the three-dimensional (3D) transport processes of reservoir temperature and pollutants is essential for water environmental protection and restoration, and introducing the lattice Boltzmann (LB) method into this prediction is necessary because of its simple algorithm, straightforward implementation of boundary conditions, and high computation efficiency. In this paper, a triple-distribution function (TDF) LB model for flow-temperature-concentration coupling simulations is introduced. Some essential techniques for implementing this method in 3D reservoirs are also described, including the treatment of water surface fluctuation, the consideration of surface heat exchange, and the hardware acceleration using the graphics processing unit (GPU). Two cases verified the proposed model, and then, the temporal-spatial variations of flow, temperature, and pollutants in the upper reservoir of a pumped-storage power station during both pumping and generating modes were analyzed to demonstrate its applicability. In the reservoir, the water forms several circulations, the cold water from the inlet flows as an undercurrent firstly, and then spread laterally, and the spreading of pollutants directly relates to the flow velocity. The results of flow, temperature, and concentration fields in different working conditions are consistent with model tests and physical laws, which shows good prospects of the proposed LB model.

     

Efficacy of vitamin-C (L-ascorbic acid) in reducing genotoxicity in fish (Oreochromis mossambicus) induced by ethyl methane sulphonate

The genotoxic effects of ethyl methane sulphonate (EMS) have been assessed in a fish, Oreochromis mossambicus with endpoints including chromosome aberrations, abnormal red blood cell nuclei, abnormal sperm morphology, and protein content (both qualitative and quantitative) of selected tissues, namely, muscle, heart, eye, brain, gill, liver, spleen and kidney. EMS caused chromosomal aberrations, nuclear anomalies in red blood cells, abnormal sperm morphology, and alteration of protein synthesis in various tissues. Some of the EMS toxicity appeared to be modulated and ameliorated in this fish by vitamin-C treatment.     

Fingerprinting and Groundwater Model Application to Evaluate Hydraulic Barrier Efficiency (Italy)

Remediation actions at contaminated sites are based on multiple numerical model scenarios considering different parameter distributions, source positions and contaminant transport paths. In some cases the excess of scenarios is due to uncertainties in the conceptual model as a result of the spread of contamination through heterogeneities in the physical system. Reduction of project hypotheses and conceptual model uncertainty is therefore needed. This result can be achieved by coupling hydrogeological investigations with environmental forensic techniques, better localization of the source and understanding of contamination history. In this respect, in the present study, compositional fingerprinting and groundwater flow modeling were applied to a former oil storage facility where, even though a hydraulic barrier had been built to stop the hydrocarbon plume, the presence of some hydrocarbons was still found in downgradient monitoring wells. The final aim was to evaluate the efficacy of the hydraulic barrier and identify of the source of pollution. Fingerprinting results indicated pollution with a gasoline-diesel mixture much altered by water washing and/or biodegradation. Comparison of seven groundwater samples collected in wells and monitoring wells was performed by analyzing the volatile fraction (BTEX) and the total ion chromatogram (TIC), focusing attention on: n-alkanes (m/z 85), alkylcyclohexanes (m/z 83), isoprenoids (m/z 113), C4-alkylbenzenes (m/z 134), C3-C6 alkylbenzenes and polycyclic aromatic hydrocarbons (PAHs). The most probable scenario was then identified by combining the results of fingerprinting with different contaminant paths obtained using the numerical model.     

Lysosomal membrane stability,phagocytosis and tolerance to emersion in the mussel Perna viridis (Bivalvia: Mytilidae) following exposure to acute,sublethal, copper

The mytilid mussel Perna viridis is distributed throughout the Indo-Pacific region and is potentially a suitable candidate for biological effects (biomarker) monitoring in the subtropics. A suite of cytological and physiological responses to acute (48-72 h) copper exposures of 50-200 microgl(-1) were assessed in order to determine the suitability of P. viridis for marine pollution monitoring. Copper elicited significant destabilisation of the haemocyte lysosomal membranes and also impaired phagocytosis. Survival during emersion following exposure to copper was not related to the experimental copper exposures suggesting that higher metal concentrations may be required to interfere with anaerobic enzymes responsible for suppression of metabolism. Based on this preliminary study, cytological biomarkers evaluated in the haemocytes extracted from P. viridis should prove an effective non-destructive means of assessing metal pollution throughout the mussels subtropical range.     

Comparison of an enzyme-linked immunosorbent assay (ELISA) to gas chromatography (GC)--measurement of polychlorinated biphenyls (PCBs) in selected US fish extracts

The analysis of PCBs in fish tissues by immunoassay methods was evaluated using fish collected from a US monitoring program, the National Contaminant Biomonitoring Program of the US Department of Interior, Fish and Wildlife Service. Selected composite whole fish samples, which represented widely varying concentrations and sources of PCBs, were extracted and subjected to congener PCB analysis by gas chromatography (GC) and total PCB analysis using an ELISA (ePCBs) calibrated against technical Aroclor 1248. PCB congener patterns in these fishes were different from the patterns found in commercial Aroclors or their combinations as demonstrated by principal component analysis of normalized GC congener data. The sum of the PCB congeners measured by GC (total-PCBs) ranged from 37 to 4600 ng/g (wet weight). Concentrations of PCBs as determined by the ELISA method were positively correlated with total-PCBs and the ePCBs/total-PCBs ratios for individual samples ranged from 1 to 6. Ratios of ePCBs/total-PCBs for dilutions of Aroclors 1242, 1254, and 1260 and for matrix spikes range from 0.6 for 1242 to 2.5 for 1254 and 1260. These results suggest that higher chlorinated PCB congeners have higher affinity for the anti-PCB antibodies. Partial least squares with latent variable analysis of GC and ELISA data of selected Aroclors and fish samples also support the conclusion that ELISA derived PCB concentrations are dependent on the degree of chlorination.