Now that the concerns, issues, ideas and constraints have been discussed, how does all of this come together? There are three basic questions we should ask.• Can we improve natural resource management through monitoring?• Will those that make the decisions listen?• Will they use the generated data in their decision?I am going to relate to you what has happened in California over the last fifteen years. I believe it will point out that the answer to the three questions are a resounding yes, with some qualifications and some bumpy roads along the way.
In order to resolve the spatial component of the design of a water quality monitoring network, a methodology has been developed to identify the critical sampling locations within a watershed. This methodology, called Critical Sampling Points (CSP), focuses on the contaminant total phosphorus (TP), and is applicable to small, predominantly agricultural-forested watersheds. The CSP methodology was translated into a model, called Water Quality Monitoring Station Analysis (WQMSA). It incorporates a geographic information system (GIS) for spatial analysis and data manipulation purposes, a hydrologic/water quality simulation model for estimating TP loads, and an artificial intelligence technology for improved input data representation. The model input data include a number of hydrologic, topographic, soils, vegetative, and land use factors. The model also includes an economic and logistics component. The validity of the CSP methodology was tested on a small experimental Pennsylvanian watershed, for which TP data from a number of single storm events were available for various sampling points within the watershed. A comparison of the ratios of observed to predicted TP loads between sampling points revealed that the model's results were promising.
Tocopilla is located on the coast of Northern Chile, within an arid region that extends from 30 degrees S to the border with Perú. The major industrial activities are related to the copper mining industry. A measurement campaign was conducted during March and April 2006 to determine ambient PM10 and PM(2.5) concentrations in the city. The results showed significantly higher PM10 concentrations in the southern part of the city (117 microg/m3) compared with 79 and 80 (microg/m3) in the central and northern sites. By contrast, ambient PM2.5 concentrations had a more uniform spatial distribution across the city, around 20 (microg/m3). In order to conduct a source apportionment, daily PM10 and PM(2.5) samples were analyzed for elements by XRF. EPA's Positive Matrix Factorization software was used to interpret the results of the chemical compositions. The major source contributing to PM(2.5) at sites 1, 2 and 3, respectively are: (a) sulfates, with approximately 50% of PM2.5 concentrations at the three sites; (b) fugitive emissions from fertilizer storage and handling, with 16%, 21% and 10%; (c) Coal and residual oil combustion, with 15%, 15% and 4%; (d) Sea salt, 5%, 6% and 16%; (e) Copper ore processing, 4%, 5% and 15%; and (f) a mixed dust source with 11%, 7% and 4%. Results for PM10--at sites 1, 2 and 3, respectively--show that the major contributors are: (a) sea salt source with 36%, 32% and 36% of the PM10 concentration; (b) copper processing emissions mixed with airborne soil dust with 6.6%, 11.5% and 41%; (c) sulfates with 31%, 31% and 12%; (d) a mixed dust source with 16%, 12% and 10%, and (e) the fertilizer stockpile emissions, with 11%, 14% and 2% of the PM10 concentration. The high natural background of PM10 implies that major reductions in anthropogenic emissions of PM10 and SO2 would be required to attain ambient air quality standards for PM10; those reductions would curb down ambient PM(2.5) concentrations as well.
The Mid-Canada Radar Line (MCRL) was built by the Canadian government during the 1950s and closed in the 1960s. MCRL Site 050 located in close proximity to Fort Albany First Nation was a source of polychlorinated biphenyls (PCBs); thus, this site was remediated in 2001. There has been concern in Fort Albany that the Albany River by MCRL Site 050 is still contaminated. We examined whether the aquatic environment surrounding MCRL Site 050 has returned to background levels four years post-remediation using leeches (Haemopis spp.) as bioindicators. Leech data for 2005 indicates that PCB levels remain higher near Site 050 than at the control site upstream; however, there has been a decrease in difference between Site 050 and the control site for leech body burden between years. Thus, the removal of the terrestrial source of PCB contamination at Site 050 appears to have removed the main source of aquatic PCBs.
Abandoned military sites in northern North America are relics of the Cold War and sources of polychlorinated biphenyls (PCBs). In the late 1990s, the Canadian federal and provincial governments began the cleanup of the mid-Canada radar line in Ontario, Canada. The first site to be remediated was Site 050 (Fort Albany First Nation) in 2001; however, the community remains concerned that contaminants may have moved prior to, during, and after remediation into the Albany River directly adjacent to Site 050. Thus, the Albany River was monitored (1999, 2001, 2002) during the remediation process to determine if the cleanup itself further contaminated the aquatic compartment, using leeches (Haemopis spp.) as bioindicators. Few organochlorines were found in leeches at levels higher than the detection limit, aside from PCBs. Leech data from the present study indicated that PCB levels were significantly higher near Site 050 than the control site upstream, indicating point source contamination from Site 050. The temporal trend in leech contaminant data indicated an increase in PCB contaminant load from 1999 (pre-remediation) to 2001 (immediately post-remediation), but this difference was not statistically significant due to high variances. Nevertheless, logit log-linear contingency modeling did reveal that immediately after cleanup (2001), contaminants (CBs 99, 118, 128, 156, 170, 183) in leeches were detected significantly more frequent than expected. When taken together, leech body burden and frequency of detection data suggest that the remediation process itself further contaminated the aquatic environment, if only temporarily. Lastly, the removal of the terrestrial source of PCBs during remediation did remove the source of aquatic contaminants in that body burden of contaminants in leeches were significantly lower a year after cleanup.
1,1,1-Trichloro-2,2-bis(p-chlorophenyl)ethane(4,4′-DDT) is a pesticide well-known for its negative health and environmental effects. Despite being banned by a majority of world countries more than 30 years ago, its persistence in the environment is a continuing problem even today. The objective of the study was the investigation of sorption/desorption behavior of 4,4′-DDT in sandy loam soil. The impact of contaminant concentration and age was observed with three different experiments. The sorption percentages at the end of the short time step (8 h) were 50 and 92 %, for initial concentrations 2.26 and 5.28 mg/L, respectively. When freshly spiked soil was subjected to a conventional sorption study, 82 to 99.6 % of the initial aqueous DDT concentrations were sorbed within 24 h. When modeled with a Freundlich isotherm, the log K
f was found to be 3.62. After six consecutive 24 h desorption steps, 33 to 96.6 % still remained in the soil. This was more pronounced for soils that had been aged for 60 days. After seven consecutive 24 h desorption steps of aged soil, the percent remaining sorbed to the soil were 44, 64, and 77 %, for 25, 250, and 500 mg/kg, respectively. All results show that 4,4-DDT has a tendency of sorbing to the soil rapidly and showing resistance to desorption. When comparing desorption values, aged soils were seen to desorb less than non-aged soils. This result was attributed to stronger binding to soil with increased contact time.
This risk assessment on 1,1,1-trichloroethane was carried out specifically for the marine environment, accordingly to the methodology laid down in the EU risk assessment Regulation (1488/94) and the Guidance Document of the EU New and Existing Substances Regulation (TGD, 1996). 1,1,1-trichloroethane is being phased out of most uses because of its ozone depletion potential (ODP) under the Montreal Protocol. Production for emissive uses has already been phased out end 1995 in Europe and 1996 in the United States, Japan and other industrial countries. The risk assessment study consists of the collection and evaluation of data on effects and environmental concentrations from analytical monitoring programmes in large rivers and estuaries in the North Sea area. The risk is indicated by the ratio of the Predicted Environmental Concentration (PEC) and the Predicted No-Effect Concentration (PNEC) for the marine aquatic environment. In total 14 studies for fish, 7 studies for invertebrates and 9 studies for algae have been evaluated. Both acute and chronic studies have been taken into account and the appropriate assessment factors have been used to calculate a PNEC value of 21 μg/l based on long term exposure. The PEC was derived from monitoring data. The PEC was set at 0.206 μg/l (worst case) and 0.024 μg/l (typical case) for coastal waters and estuaries and 0.6 μg/l (worst case) and <0.1 μg/l (typical case) for river waters. The calculated PEC/PNEC ratios, which do not take into account any dilution factor within the sea, correspond to a safety margin of 35 to 1000 between the aquatic effect and the exposure concentration. 1,1,1-trichloroethane is not a 'toxic, persistent and liable to bioaccumulate' substance according to the criteria as mentioned by the Oslo and Paris Conventions for the Prevention of Marine Pollution (OSPAR-DYNAMEC). It can be concluded that the present use of 1,1,1-trichloroethane does not present a risk to the marine aquatic environment.
This study reports a very selective, easy, and precise method for rapid separation of trace amounts of copper in aqueous samples using octadecyl silica-bonded phase membrane disks modified by 2,2'-[ethane-1,2-diylbis(thio)]dianiline (EDTD) combined with flame atomic absorption spectrometric determination. In addition, the synthesis and spectral characterization of EDTD have been described in detail. All the affecting experimental variables such as pH, amount of modifier, eluent type, sample and eluent flow rate, interfering ions, and disk capacity were also investigated. The target analyte (trace copper) was quantitatively retained at pH = 4 and eluted with 6.0 mL of 0.5 M HNO3 at flow rates of 40 and 10 mL min(-1) for analyte passage and elution steps, respectively, through the disks modified with 17.0 mg of EDTD. The proposed method also allows an enrichment factor of about 500 and has a detection limit of 0.005 ng mL(-1). The method has been successfully applied for isolation and determination of copper in different water samples, peppers, and standard alloys.
The aim of the present work is the assessment of a new sorbent, prepared using silica gel coated with a pyrimidine derivative (allyl 6-methyl-4-phenyl-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate), for extraction and preconcentration trace amount of lead from different samples prior to determination by flame atomic absorption spectrometry. Common coexisting ions did not interfere with the separation and determination of lead at pH 6, so that lead ion completely adsorbed on the column. The limit of detection based on three times the standard deviation of the blank was found to be 0.53 ng mL(-1) in original solution. Obtained sorption capacity for 1 g sorbent was 5.0 mg Pb. The linearity was maintained in the concentration range of 0.1-30.0 ng mL(-1) for the concentrated solution. Eight replicate determinations of 2.0 μg mL(-1) of lead in the final solution gave relative standard deviation of ±2.6 %. The proposed method was successfully applied to the determination trace amounts of lead in the environmental samples such as carrot, rice, zardchoobe, and real water samples.
This risk assessment on 1,4-dichlorobenzene was carried out for the marine environment, following methodology given in the EU risk assessment Regulation (1488/94) and Guidance Document of the EU New and Existing Substances Regulation (TGD, 1996). Data from analytical monitoring programs in large rivers and estuaries in the North Sea area were collected and evaluated on effects and environmental concentrations. Risk is indicated by the ratio of predicted environmental concentration (PEC) to predicted no-effect concentration (PNEC) for the marine aquatic environment. In total, 17 data for fish, 9 data for invertebrates and 7 data for algae were evaluated. Acute and chronic toxicity studies were taken into account and appropriate assessment factors used to define a final PNEC value of 20 microg/l. Recent monitoring data indicate that 1,4-dichlorobenzene levels in coastal waters and estuaries are below the determination limit of 0.1 microg/l used in monitoring programs. The worst case value recorded in river water is below 0.45 microg/l. Using these values, calculated PEC/PNEC ratios give safety margins of about 40-200, taking no account of dilution in the sea. Environmental fate and bioaccumulation data indicate that current use of 1,4-dichlorobenzene poses no risk to the aquatic environment.
Vegetation water content could possibly provide widespread utility in agriculture, forestry and hydrology. In this article, three species leaves were measured radiometrically in order to determine a relationship between leaf water status and the spectral feature centered at 1,450 and 1,940 nm where there are strong water absorptions. The first step of our research is to measure leaf spectra with a FieldSpec-FR. After the spectral analysis using the continuum removal technique, the spectral absorption feature parameters: absorption band depth (D (1450), D (1940)), the normalized band depth of absorption in 1,450 and 1,940 nm (BNA(1450), BNA(1940)), the ratio of the two reflectance of continuum line (R (1450i )/R (1940i )), the ratio of the two band depth (D (1450)/D (1940)) and the ratio of the two absorption areas (A (1450)/A (1940)) in the two wavebands were extracted from each leaf spectrum. The fuel moisture content (FMC), specific leaf weight (SLW), equivalent water thickness (EWT) were measured for each leaf sample. A correlation analysis was conducted between the spectral absorption feature parameters and corresponding FMC, SLW and EWT. In addition, some existing indices for assessing water status such as WI (water index), WI/NDVI (water index/normalized difference vegetation index), MSI (moisture stress index), NDWI (normalized difference water index)were calculated and the correlation between them and water status were analyzed too. The results by comparing the correlations indicated that the spectral absorption feature indices we proposed were better. The indexes BNA(1940), D (1450)/D (1940), and A (1450)/A (1940) were well correlated with FMC, and the correlation between the indexes D (1450,) D (1940), R (1450i )/R (1940i ) and EWT were strong. The index A (1450)/A (1940) was tested to be a good indictor for evaluating plant water content, because there was strongest positive correlation between it and FMC than other indices.
Assessment of indoor air quality (IAQ) in classrooms of school buildings is of prime concern due to its potential effects on student’s health and performance as they spend a substantial amount of their time (6–7 h per day) in schools. A number of airborne contaminants may be present in urban school environment. However, respirable suspended particulate matter (RSPM) is of great significance as they may significantly affect occupants’ health. The objectives of the present study are twofold, one, to measure the concentrations of PM10 (<10 \(\upmu \)m), PM2.5 (<2.5 \(\upmu \)m), and PM1.0 (<1.0 \(\upmu \)m) in naturally ventilated classrooms of a school building located near a heavy-traffic roadway (9,755 and 4,296 vehicles/hour during weekdays and weekends, respectively); and second, to develop single compartment mass balance-based IAQ models for PM10 (NVIAQMpm10), PM2.5 (NVIAQMpm2.5), and PM1.0 (NVIAQMpm1.0) for predicting their indoor concentrations. Outdoor RSPM levels and classroom characteristics, such as size, occupancy level, temperature, relative humidity, and CO2 concentrations have also been monitored during school hours. Predicted indoor PM10 concentrations show poor correlations with observed indoor PM10 concentrations (R
2 = 0.028 for weekdays, and 0.47 for weekends). However, a fair degree of agreement (d) has been found between observed and predicted concentrations, i.e., 0.42 for weekdays and 0.59 for weekends. Furthermore, NVIAQMpm2.5 and NVIAQMpm1.0 results show good correlations with observed concentrations of PM2.5 (R
2 = 0.87 for weekdays and 0.9 for weekends) and PM1.0 (R
2 = 0.86 for weekdays and 0.87 for weekends). NVIAQMpm10 shows the tendency to underpredict indoor PM10 concentrations during weekdays as it does not take into account the occupant’s activities and its effects on the indoor concentrations during the class hours. Intense occupant’s activities cause resuspension or delayed deposition of PM10. The model results further suggests conductance of experimental and physical simulation studies on dispersion of particulates indoors to investigate their resuspension and settling behavior due to occupant’s activities/movements. The models have been validated at three different classroom locations of the school site. Sensitivity analysis of the models has been performed by varying the values of mixing factor (k) and newly introduced parameter R
c. The results indicate that the change in values of k (0.33 to 1.00) does not significantly affect the model performance. However, change in value of R
c (0.001 to 0.500) significantly affects the model performance.
Produced water is water trapped in underground formations that is brought to the surface along with oil or gas production. Oilfield impacted soil is the most common environmental problem associated with oil production. The produced water associated with oil-production contaminates the soil and causes the outright death of plants, and the subsequent erosion of topsoil. Also, impacted soil serves to contaminate surface waters and shallow aquifers. This paper is intended to provide an approach for full characterization of contaminated soil by produced water, by means of analysis of both the produced water and the impacted soil using several recommended analytical techniques and then identify and assay the main constituents that cause contamination of the soil. Gialo-59 oilfield (29N, 21E), Libya, has been chosen as the case study of this work. The field has a long history of petroleum production since 1959, where about 300,000 bbl of produced water be discharged into open pit. Test samples of contaminated soil were collected from one of the disposal pits. Samples of produced water were collected from different points throughout the oil production process, and the analyses were carried out at the labs of Libyan Petroleum Institute, Tripoli, Libya. The results are compared with the local environmental limiting constituents in order to prepare for a plan of soil remediation. The results showed that the main constituents (pollutants) that impact the soil are salts and hydrocarbon compounds. Accordingly; an action of soil remediation has been proposed to remove the salts and degradation of hydrocarbons.
Metals and radionuclide levels in marine birds of the Aleutians are of interest because they are part of subsistence diets of the Aleut people, and can also serve as indicators of marine pollution. We examined geographic and species-specific variations in concentrations of radionuclides in birds and their eggs from Amchitka, the site of underground nuclear tests from 1965 to 1971, and Kiska Islands (a reference site) in the Aleutians, and the levels of lead, mercury and cadmium in eggs. In 2004 we collected common eiders (Somateria mollissima), tufted puffins (Fratercula cirrhata), pigeon guillemot (Cepphus columba) and glaucous-winged gulls (Larus glaucescens) from Amchitka and Kiska, and eggs from eiders and gulls from the two island. We also collected one runt bald eagle (Haliaeetus leucocephalus) chick from both Amchitka and Kiska Islands. For most species, the levels of radionuclide isotopes were below the minimum detectable activity levels (MDA). Out of 74 cesium-137 analyses, only one composite (gulls) was above the MDA, and out of 14 composites tested for plutonium (Pu-239, 240), only one exceeded the MDA (a guillemots). Three composites out of 14 tested had detectable uranium-238. In all cases, the levels were low and close to the MDAs, and were below those reported for other seabirds. There were significant interspecific differences in metal levels in eggs: gulls had significantly higher levels of cadmium and mercury than the eiders, and eiders had higher levels of lead than gulls. There were few significant differences as a function of island, but eiders had significantly higher levels of cadmium in eggs from Kiska, and gulls had significantly higher levels of mercury on Kiska. The levels of cadmium and mercury in eggs of eiders and gulls from this study were above the median for cadmium and mercury from studies in the literature. The levels of mercury in eggs are within the range known to affect avian predators, but seabirds seem less vulnerable to mercury than other birds. However, the levels of mercury are within the action levels for humans, suggesting some cause for concern if subsistence Aleuts eat a large quantity of eggs.
The physicochemical analyses of pulp-paper mill effluent revealed that it was dark brown with 1761 ± 2.3 color PtCo units having slightly alkaline pH, high biological oxygen demand and chemical oxygen demand values, and contained large quantities of organic and inorganic constituents, well above the prescribed standards. The bacterial growth, color reduction, and dechlorination were evident in all the four sets of experiments with different possible combinations of nutrient supplementation and Pseudomonas putida augmentation. A high degree of decolorization at 29.7% and 27.4% was observed by the effluent native microflora during 48 and 24 h, in unaugmented effluent supplemented with glucose + yeast extract and glucose + peptone, respectively. The extent of decolorization in glucose + yeast extract unaugmented effluent also corresponded with high degree of dechlorination (59.3%) during 60-h incubation (SET III). An appreciable level of growth, decolorization, and dechlorination was evident in nutrient unsupplemented P. putida augmented effluent as well as in the control natural effluent. However, a maximum level of growth response (OD 1.641-1.902) during 36-48 h, removal of color (39.72-48.2%) during 24-36 h, and chloride ions (80.1-83.5%) during 36 h was achieved in P. putida augmented effluent supplemented with glucose + yeast extract or peptone. Therefore, supplementation of effluent with glucose and yeast extract or peptone and concomitant augmentation with P. putida is required for efficient effluent decolorization and detoxification.
Since the early 1970's, remote sensing has been used to study ocean dumping at some of the hearshore ocean dump sites off the coast of the United States, but little remote sensing had been done over the deep water ocean disposal sites. This report summarizes what has been learned from the remote sensing of ocean dumping by the Landsat satellites at Deep Water Dumpsite 106. Of the three major types of waste material discharged at Deep Water Dumpsite 106, only the titanium pigment process acid waste has been sighted. From early in 1977 to May 1979, 11 acid dumps were observed by Landsat. All five of the dumps sighted in 1977 occurred within warm core Gulf Stream eddies and the plumes moved clockwise within the eddies. Four of those dumps were seen to be located northeast of the original dump location while the fifth one was sighted south of the original dump location. The six remaining observed dumps, discharged in the absence of an eddy, were seen to be located generally south of the original dumping locations. The average speed of the dump movement was 0.68 kt with a range from 0.17 to 1.17 kts. Plume dispersion showed a tendency toward greater dispersion as the plume got older with the widest plume cross section measured on the order of 2100 m.
Over the past decade, an increased tendency to consume meals at dining facilities outside the home has been highlighted; moreover, meals supplied in food businesses have been involved in many foodborne disease outbreaks. Therefore, microbial air contamination in food processing facilities could be a concern and an increase of microbial loads could represent a risk factor, especially for the potential contamination of foods due to undesirable spoiling and pathogenic bacteria. In this paper, the results of an 11-year microbiological monitoring of air quality in a university canteen are reported. The study, which started in the year 2000, was performed within a hazard analysis and critical control point (HACCP) plan implementation of a canteen that produces about 1,000 meals a day in order to verify the effectiveness of corrective actions on the indoor air quality. The primary food preparation room, the kitchen, and three cold rooms underwent air sampling by using a calibrated impaction sampler. Our investigation detected a general and progressive improvement in the air quality of the canteen since the beginning of the study, thus suggesting the appropriateness of the corrective action undertaken during the HACCP implementation program.
The background concentrations of atmospheric CFC-11 and CFC-12 were monitored to assess their impact on stratospheric ozone depletion and global warming from September 1995 to March 1999 at Kosan, Korea, located at eastern margin of the Asian Continent. The concentrations of atmospheric CFC-11 at Kosan have decreased slightly, at a rate of -2.5 pptv yr(-1), over the period in response to the Montreal Protocol. The CFC-12 mixing ratio at Kosan continues to increase in the atmosphere at a rate of 5.7 pptv yr(-1) despite international regulations, because of its extreme atmosphere persistence. Recent trends of these two chlorofluorocarbons at Kosan, Korea were concordant with those of the northern hemispheric background monitored unit at Mauna Loa, Hawaii. The maximum seasonal mean mixing ratios of CFC-11 and CFC-12 at Kosan, Korea, were 270 +/- 4 pptv in the spring and 538 +/- 9 pptv in the winter, and the corresponding seasonal minima were 267 +/- 7 and 529 +/- 12 pptv. This occurred in the summer and was due to southeasterly winds from the northwestern Pacific Ocean. By performing a three-day isentropic backward trajectory analysis, it was shown that air masses at Kosan, and with the exception of summer, mainly originated from central and northern China. In particular, the mixing ratios of these two contaminant species are closely related with their air mass trajectories.
To understand electromagnetic radiation field strength and its influencing factors of certain 110-kV high-voltage lines in one urban area of Chongqing by measuring 110-kV high-voltage line's electromagnetic radiation level. According to the methodology as determined by the National Hygienic Standards, we selected certain adjacent residential buildings, high-voltage lines along a specific street and selected different distances around its vertical projection point as monitoring points. The levels of electromagnetic radiations were measured respectively. In this investigation within the frequency of 5-1,000 Hz both the electric field strength and magnetic field strength of each monitoring sites were lower than the public exposure standards as determined by the International Commission on Non-Ionizing Radiation Protection. However, the electrical field strength on the roof adjacent to the high-voltage lines was significantly higher than that as measured on the other floors in the same buildings (p < 0.05). The electromagnetic radiation measurements of different monitoring points, under the same high-voltage lines, showed the location which is nearer the high-voltage line maintain a consistently higher level of radiation than the more distant locations (p < 0.05). Electromagnetic radiation generated by high-voltage lines decreases proportionally to the distance from the lines. The buildings can to some extent shield (or absorb) the electric fields generated by high-voltage lines nearby. The electromagnetic radiation intensity near high-voltage lines may be mitigated or intensified by the manner in which the high-voltage lines are set up, and it merits attention for the potential impact on human health.
An ongoing biomonitoring program using oysters (Crassostrea virginica) was implemented in 1978 to monitor radionuclide releases from the Calvert Cliffs Nuclear Power Plant located on Chesapeake Bay. The program involves quarterly removal and replenishment of oysters located in a tray about 0.2 km from the effluent discharge. Radiosilver (Ag-110m) concentrations in tray oysters (pCi/kg ww) were analyzed using ANCOVA-like models with plant releases of Ag-110m in the present and immediately preceding quarters and season of exposure as explanatory variables. Hypothesis testing based on the estimated models and comparison among model predictions under hypothetical release scenarios showed that season of exposure was important in influencing Ag-110m concentrations, with exposure during the Fall and Summer seasons resulting in significantly higher Ag-110m concentrations in tray oysters than exposure during the Winter and Spring seasons. From a management perspective of minimizing Ag-110m concentrations in oysters located near the plant, Winter and Spring are the preferred seasons for plant releases.
This study is based on 82 days of continuous air-quality monitoring using two mobile monitoring vans provided by the Taiwan Environmental Protection Administration (TEPA). The purpose of the study is to reveal variations of air quality without forced ventilation from on-road emissions of light-duty vehicles (LDV) inside the Hsuehshan Tunnel. Since it was opened to traffic in June 2006, only LDV have been allowed to pass the Hsuehshan Tunnel, the longest tunnel in Taiwan and in Asia. The hourly concentrations of air pollutants at four monitoring sites inside the tunnel (pollutant: downslope entrance, downslope exit, upslope entrance, upslope exit) are as follows: (CO: 6.9±5.4, 13.6±8.7, 4.6±3.2, 14.6±8.0 ppm), (NOX
: 534±311, 1198±640, 460±242, 1704±692 ppb), (SO2: 7±5, 18±10, 9±4, 26±10 ppb), (NMHC: 1.9±2.5, 3.5±3.0, 0.8±0.9, 2.7±1.9 ppm), (PM10: 50±28, 62±29, 59±25, 85±30 μg m−3), and (PM2.5: 31±18, 45±22, 35±18, 62±23 μg m−3). The emission factors (EFs) from LDV in this study (pollutant: downslope EF, upslope EF in mg veh−1 km−1) is estimated respectively as follows: (CO: 909±469, 1468±631), (NOX
: 145±67, 331±166), (SO2: 3±2, 6±3), (NMHC: 96±65, 121±63), (PM10: 2±2, 5±4), and (PM2.5: 2±2, 4±3). It shows that the upslope pollutant EFs are twice as big as those of the downslope. However, among these EFs, the NMHC EF is less affected by the road gradient. Likewise, its upslope EF is only 1.3 times as big as that of the downslope. In summary, the results are useful for examining the emissions from the local fleet of vehicles under the driving conditions present during the study and for observing the changes in fleet emission rates upon future replication of the study.
Cadmium and lead were determined simultaneously in seawater by differential pulse stripping voltammetry (DPSV) preceded by adsoptive collection of complexes with 8-hydroxyquinoline (oxine) on to a hanging mercury drop electrode (HMDE). In preliminary experiments the optimal analytical condition for oxine concentration was found to be 2.10(-5) M, at pH 7.7, the accumulation potential was -1.1 V, and the initial scannig potential was -0.8 V. The peak potentials were found -0.652 V for Cd and -0.463 V for Pb At the 60 s accumalation time. The limit of detection (LOD) and limit of quantitatification (LOQ) were found to be by voltammetry as 0.588 and 1.959 microg l(-1) (RSD, 5.50%) for Cd and 0.931 and 3.104 microg l(-1) (RSD, 4.10%) for Pb at 60 s stirred accumulation time respectively. In these conditions the most of the seawater samples are amenable for direct voltammetric determination of cadmium and lead using a HMDE. An adsorptive stripping mechanism of the electrode reaction was proposed. For the comparison, seawater samples were also analysed by ICP-atomic emission spectrometry method (ICP-AES). The applied voltammetric technique was validated and good recoveries were obtained.
The problem of managing scientific information for widespread availability and use can be overwhelming. At Oregon State University, the Quantitative Sciences Group has found a workable solution. The group has developed a Forest Science Data Bank (FSDB) to house data generated by scientists and collaborating researchers in the Andrews Long-Term Ecological Research program. Today the FSDB houses some 2400 data sets from over 350 existing ecological studies and adds about 20 new studies yearly. This paper describes what we have learned in setting up the FSDB as a facility that can be used by researchers who both deposit information in and retrieve information from the FSDB.