Monitoring the condition of the Canadian forest environment: The relevance of the concept of ‘ecological indicators’

The Canadian forest environment is characterized by high spatial and temporal variability, especially in the west. Our forests vary according to climate, landform, and surficial geology, and according to the type, intensity, extent of, and the time since the last disturbance. Most Canadian forests have had a history of repeated acute, episodic disturbance from fire, insects, wind, diseases and/or logging, with a frequency of disturbance varying from a few decades to many centuries. These sources of variability have resulted in a complex and continually changing mosaic of forest conditions and stages of successional development.Monitoring the quality of this dynamic forested landscape mosaic is extremely difficult, and in most cases the concept of a relatively simple index of forest ecosystem quality or condition (i.e. an ecological indicator) is probably inappropriate. Such ecological indicators are better suited for monitoring chronic anthropogenically induced disturbances that are continuous in their effect (e.g. acid rain, heavy metal pollution, air pollution, and the greenhouse effect) in ecosystems that, in the absence of such chronic disturbance, exhibit very slow directional change (e.g. lakes, higher order streams and rivers). Monitoring the effects of a chronic anthropogenic disturbance to forest ecosystems to determine if it is resulting in a sustained, directional alteration of environmental quality will require a definition of the expected pattern of episodic disturbance and recovery therefrom (i.e. patterns of secondary succession in the absence of the chronic disturbance). Only when we have such a temporal fingerprint of forest ecosystem condition for normal patterns of disturbance and recovery can we determine if the ecosystem condition is being degraded by chronic human-induced alteration of the environment. Thus, degradation is assessed in terms of deviations from the expected temporal pattern of conditions rather than in terms of an instantaneous assessment of any particular condition. The concept of ecological rotation (the time for a given ecosystem to recover from a given disturbance back to some defined successional condition) is useful in the definition of these temporal fingerprints. This requires information on the intensity of disturbance, the frequency of disturbance, and the rate of successional recovery. Only when all three of these are known or estimated can statements be made as to whether the ecosystem is in a longterm sustainable condition or not.The somewhat overwhelming complexity of this task has led forest ecologists to use ecosystem-level computer simulation models. Appropriately structured and calibrated models of this type can provide predictions of the overall temporal patterns of ecosystem structure and functions that can be expected to accompany a given frequency and character of episodic disturbance. Such models can also be used to examine the long-term consequences of chronic disturbances such as acid rain and climatic change. Predictive ecosystem-level models should be used in conjunction with some method of stratifying the inherent spatial biophysical variability of the forest environment, such as the biogeoclimatic classification system of British Columbia.     

Temperature and Concentration Effects in Biomonitoring of Organic Air Pollutants

Up to now only very few studies in biomonitoring of organic air pollutants have been published taking into account the strong influence mean temperatures have on the accumulation process into plants during the course of the exposition. Temperature governed sorption as well as the plants vitality pose a major source of uncertainty making inter-study comparisons difficult. Different surface-to-volume ratios of plant foliage lead to strongly varying concentration effects in different plant species. Moreover a plants content of waxes and lipids must be considered in order to relate xenobiotic concentrations to the compounds being most efficient in the bioaccumulation process. Some of these factors are evaluated in regard to the use of plants as biomonitors for organic air pollutants. Another aim is to deduce the mean ambient gas phase concentrations from PAH concentrations determined in the biomonitor plants using vegetation-air partitioning coefficients which have been corrected for temperature dependent sorption as well as the plants lipid content. Restrictions of such approaches and methods of biomonitoring in general are discussed.     

Comparative Studies on the Usefulness of Seven Ecological Indices for the Marine Coastal Monitoring Close to the Shore on the Swedish East Coast

The simultaneous behaviour of seven ecological indices(Hurlberts, Margalefs, Menhinicks, Shannons,species number, Jaccards and saprobic index) wasstudied based on phytoplankton data close to the shoreon the East coast of Sweden during the summer 1998.The sampling stations had a similar eutrophicationlevel and were located in bays. Standard phytoplanktondatabases were used in calculating the indices, whichwere later compared using cluster analysis.Hurlberts, Margalefs, Menhinicks, Shannons andspecies number indices, as measure of communitydiversity, produced similar trends which oftendiffered from those based on Jaccards index ofsimilarity. However, the simultaneous use of theseindices was found meaningful as a possible part of themonitoring close to the shore. The application of asaprobic index lead to erroneous conclusions in thestudied case.     

Correlation between environmental parameters and leaf injury in Nicotiana tabacum L. cv. ‘Bel-W 3’

Tobacco plants (Nicotiana tabacum L. cv. Bel-W3) were exposed to ambient air for 25 weeks during the 1987 growing season next to an air pollution monitoring station in Brera (Milan, Italy). The research objective was to study the influence of selected environmental parameters on leaf damage in this plant, which is widely used as an ozone indicator. A multiple linear correlation model was estimated between leaf damage and available meteorological and air pollution data. Leaf injury was positively correlated with ozone integrated exposure and temperature, but negatively with vapour pressure deficit. A linear correlation model was used to estimate ozone integrated exposure from the leaf injury indexWork carried out as part of the research programme: ENEL's contribution to the knowledge of important environmental issues, research line: Effects of atmospheric pollution on the land.     

Application of remote sensing to exposure monitoring

Although exposure assessments cannot be completed remotely, remote sensing techniques provide an invaluable adjunct in exposure monitoring programs. Exposure can be defined as the summation over time, in all media, of the amount of a pollutant available at the exchange boundaries of the receptor during a specified period. This paper describes a few remote monitoring techniques that provide direct measurement input into an exposure assessment and several that furnish quantitative or qualitative information leading to decisions regarding how to monitor, such that the source-exposure-dose relationships can be fully defined. Two general classes of remote sensing systems are included in this discussion-passive and active. Passive systems depend on a measurement of the energy reflected or emitted by a target and active systems use an energy source, e.g., a laser to perform the environmental interrogation. Airborne as well as ground-based remote monitoring measurements or systems are also considered in this paper.     

Ozone biomonitoring in Northern Italy

This report presents the results of an ozone monitoring experience performed with tobacco indicator plants (Nicotiana tabacum L. cv. Bel-W3). These bioindicators were exposed to ambient air in 23 sites in Northern Italy from 27 April 1987 to 21 October 1987. Typical ozone-induced leaf necrosis was observed in every site. The percentage increase in injured leaf area was estimated weekly and a Leaf Injury Index (LII) was calculated. The weekly series of LIIs were statistically inspected for spatial and temporal relationships. Sample correlation coefficients were statistically significant for almost every possible pair of sites. The time series properties of ten series of LIIs with no missing data were analyzed using Box-Jenkins models. An autoregressive first order model, or AR(1), was selected to remove the autocorrelation from these series. Linear correlation coefficients between prewhitened (i.e. from which autocorrelation had been removed) pairs of LII series were statistically significant. Hence synchronous variations in leaf necrosis could only be related to the regional diffusion of tropospheric ozone.Work carried out as part of the research programme: ENEL's contribution to the knowledge of important environmental issues, Research line; Effects of atmospheric pollution on the land.     

Exposure estimates in assessing helath effects of air pollution

Air pollution has been associated with adverse health effects. Difficulties in interpreting studies of health effects of exposure to air pollution arise in estimating exposure. Until recently, studies of effects of air pollution have relied on pollution exposure measurements obtained from fixed location air pollution stations monitoring outside air (to evaluate compliance with air quality standards, rather than to examine population exposure). However, recent evidence suggests that there are substantial differences between air pollution levels measured at such sites and levels to which people are actually exposed, i.e. personal exposure. The present study examines effects of ambient urban air pollution on persons suffering from asthma, healthy non-asthmatic subjects and school children (in 2 Canadian cities, Toronto and Hamilton). Air pollution exposure is being assessed by data obtained from: (1) conventional abatement oriented fixed location air pollution monitoring stations, (2) an extensive population oriented network, (3) inside and (4) outside structures (homes and schools) as well as (5) personal air pollution samplers. The data indicate variability in these different estimates of exposure which have implications on health effects assessment.     

Respiratory Suspended Particulate (RSP) Concentration and its Implications to Roadside Workers: A Case Study of Hong Kong

The adsorption behaviour of Diphenylamine (DPAM), napthylamine ( NAM), napthylamine ( NAM)and aniline on pyrolusite and activated carbon has been studied.Pyrolusite shows remarkable sorption capacity for DPAM and NAM as compared to aniline; (the adsorption followed theorder:Activated Carbon: DPAM = NAM > AnilinePyrolusite: DPAM: NAM > NAM> Aniline)The maximum adsorption of NAM occurred in theconcentration range 4–20 g mL^-1 on pyrolusite (95%)and 4–50 g mL^-1 on activated carbon (100%). Theeffect of various doses of activated carbon on the adsorption of NAM confirm Langmuir and Freundlich isotherms where asFreundlich isotherm is obeyed by pyrolusite. The adsorption of NAM on both the absorbents is not affected in presence ofDPAM over a wide range of their initial concentrations (20–60g mL^-1). The desorption studies of NAM onpyrolusite was carried out by batch as well as column processes.Excellent results were obtained when a mixture of n-hexane andisopropanol (91:1) was used as eluent.     

Soil-Water Partitioning and Desorption Hysteresis of Volatile Organic Compounds from a Louisiana Superfund Site Soil

The adsorption and desorption of three volatile organic compounds (1,2- dichloroethane, 1,1,2- trichloroethane and 1,1,2,2-tetrachloroethane) from a previously uncontaminated clayey soil sample from a Superfund site in North Baton Rouge,Louisiana was studied. In the linear range of the adsorption isotherm, the partition constants were not affected by the presence of the co-solutes. The adsorption isotherms over a wide concentration range on the soil followed the nonlinearFreundlich isotherm. The desorption of the compounds showedsignificant hysteresis at all concentrations studied. Approximately 20 to 70% of the adsorbed mass of organic compounds resisted the desorption even after five months ofsuccessive desorption steps. The desorption of four compounds(1,2-dichloroethane, 1,1,2-trichloroethane, 1,4-dichlorobenzeneand hexachlorobutadiene) from a contaminated soil sample fromthe same site was also studied. The aqueous concentration declined as the successive desorption steps progressed. For hexachlorobutediene the desorption can be visualized as occurring in two stages. The first stage involved a loosely bound or reversible fraction and the second stage involveda tightly bound or resistant fraction.     

Application of CFD Methods for Modelling in Air Pollution Problems: Possibilities and Gaps

Different urban air pollution problems deal with complex structure of air flows and turbulence. For such problems the Computer Fluid Dynamics (CFD) methods become widely used. However, this approach despite a number of advantages has some problems. Experience of use of CFD tools for development of models and suggestions of their applications for a local scale air pollution over a complex terrain and stable stratification are discussed in this paper, including: Topography and complex geometry: choose of the co-ordinate system and computer grid; Turbulence closure for air pollution modelling: modified k- model for stable stratified ABL; Boundary conditions for vertical profiles of velocity for stable-stratified atmosphere; Effects of the radiation and thermal budget of inclined surfaces to dispersion of pollutants; Artificial sources of air dynamics and circulation.Some examples of CFD applications for air pollution modelling for a flat terrain, mountainous area, mining open cast and indoor ventilation are discussed. Modified k- model for stably-stratified ABL is suggested. Due to the isotropic character of the k- model a combination of it in vertical with the sub-grid turbulence closure in horizontal can be more suitable for ABL. An effective scheme of boundary conditions for velocity profiles, based on the developed similarity theory for stable-stratified ABL, is suggested. Alongside with the common studies of atmospheric dispersion, the CFD methods have also demonstrated a good potential for studying anthropogenic and artificial-ventilation sources of air dynamic and circulation in local-scale processes of air pollution.     

Field Study of Wind and Traffic to Test a Street Canyon Pollution Model

In the U.K., local authorities have new duties to review and assess air quality. Dispersion models are important tools in this process. The performance of a street canyon model, AEOLIUS, in calculating carbon monoxide (CO) concentrations in urban areas is discussed. A field experiment was conducted in a busy street canyon in Leek, Staffordshire. Wind speed and direction were measured at three heights adjacent to the street. The canyon's CO concentrations and traffic counts were recorded. Predicted concentrations of CO, calculated using AEOLIUS, were compared with the observed values. The concept of a roof-top wind is discussed, as are the consequences of using wind measurements from outside the town. Choice of wind measurement location and height of the anemometer above the canyon had a pronounced effect on calculating the roof-top wind. Two methods of deriving a street level wind speed from a roof-top wind speed gave results that differ by up to a factor of two. AEOLIUS had variable skill at predicting CO concentrations depending on the roof-top wind direction: possible reasons for this variability are explored. A sensitivity study of the model showed that vehicle emissions have the greatest impact on predicted concentrations. Implications for local air quality management are discussed.     

Health hazard assessment in an industrial town with the help of GRAM-GIS

Unplanned industrialization and urbanization are causing health hazard mainly in developing countries. It is essential to assess the magnitude of future hazard in an industrial town. The geographical information system is a special type of tool evolved to analyse geographic data for efficient planning. In India large-scale industrialization started after independence. New industrial towns have been established and Durgapur in West Bengal is one of them. In this study an indigenously developed GIS package GRAM has been used to assess air quality in Durgapur town. Using GIS, interpolated maps have been prepared showing the distribution of five pollutants, i.e. carbon monoxide, total oxidant, nitrogen-oxide, sulfur-dioxide and suspended particulate matter. The maps have been used to find the pollutant standard index of the area. The final map shows that the PSI index is high and ranges between the unhealthy to very unhealthy category. This map has been combined with a present landuse pattern. There are three pockets of extremely poor air quality zones which generally match with industrial units. Areas around these units are the potential zones of health hazard. Large numbers of patients admitted in hospitals here suffer from obstructive diseases. Most of them belong to the working age group. This may indicate that the main work force is exposed to the health hazard due to industrial pollution.     

Bio-indicators and the quality of the Wadden Sea

The definitions of the notions bio-indicator and water quality are critically reviewed; it is shown that both have been used ambiguously.The quality of the Wadden Sea is discussed using a number of indicators for pollution effects; the Wadden Sea is now an unsuitable environment for a number of marine mammals, and, to a lesser extent, for some bird species. It cannot be shown whether or not this pollution has any effect on r-selective species.Paper presented at a Symposium held on 14 and 15 October 1982, in Utrecht, The Netherlands.     

Background Levels of Metals in Soils, McMurdo Station, Antarctica

McMurdo Station is the largest research station in Antarctica, with a population that ranges each year from 250 to 1200 people. Because of its size and 40-year history of use, a number of locations around the station have become contaminated with wastes. Soils and sediments in these areas have been shown to contain elevated levels of petroleum-related products, PCBs, other organics, and metals. While some remedial investigations have been conducted, background levels of metals in soils have not been determined. This paper reports on background levels of metals in a natural basalt-derived soil (gray soil) and scoria (soft porous rock used as fill, red soil) near McMurdo Station using two fundamentally different analytical procedures, concentrated acid extraction/analysis and total metals. These data facilitate determining the extent and levels of metal contamination near McMurdo Station and provide reference levels of metals for comparison with existing and future remediation data. There were statistically significant differences between metals concentrations in both gray and red soils, and no correlations between the level of extracted versus total metal. Generally, only a small fraction of a metal was extractable.     

Popular Cognition of National Monuments in Singapore

Monumental features or landmarks in the urban built environment are distinguished by clear form, prominent location, a high degree of visibility and in Lefebvres (1991:143) words, "impose a clearly intelligible message". In Singapore, the gazetting and preservation of national monuments come under the ambit of the Preservation of Monuments Board. From the states perspective, national monuments embody historical value: as enduring landmarks of the city which link the present to the past, they give "lithic memory to the life of a nation" and are integral to the process of building national solidarity, identity and pride. This paper examines popular cognition of Singapores national monuments, that is, the extent to which the general public are able to identify gazetted monuments in visual and nomenclatural terms. A questionnaire survey of 284 respondents selected from a public housing estate as well as in-depth interviews with a smaller sample yielded information on Singaporeans visual recognition, nomenclatural accuracy and historical knowledge with respect to national monuments. The results showed that while visual identification of monuments was strong and the public could clearly identify the main attributes and general forms which national monuments take, the specific names of these monuments were often overlooked and historical knowledge of them rather shallow. In the conclusion, it is argued that if monuments are to serve their purpose as the countrys "psyche" annd "memory", deeper knowledge of the history and meaning behind these monuments must be inculcated in the Singaporean consciousness.     

Establishing a standard Sonoran Reference Plant and its application in monitoring industrial and urban pollution throughout the Sonoran Desert

Using analyses from honey mesquite (Prosopis glandulosa) leaves from nearly pristine locations in Arizona, an inorganic plant concentration standard is proposed for use as a Sonoran Reference Plant (SRP). Such a standard can be used as a monitoring device for different anthropogenic pollution sources throughout the Sonoran Desert. To test the application of the SRP, honey mesquite leaves were collected at different sites in southern Arizona and their chemical fingerprints compared to SRP. Sources of element origin were identified through factor analysis and correlation matrices. A terrestrial factor was found in leaves from all sites. Anthropogenic factors varied for different sites. Mesquite leaves accumulated significant amounts of elements originating from copper smelters (As, Sb) and urban pollution (La, Sm, Ce, V). These pollutants are small-sized and have been linked to human lung diseases. Mesquite is a deciduous tree; the yearly comparison of mesquite leaf element concentration spectra to the SRP standard can be used to determine seasonal improvement or deterioration of environmental quality in a particular area.     

Planning Tools for Developing Comprehensive Regional Monitoring Programs

We present a planning framework that structures thelarge amount of interrelated information involved indeveloping regional monitoring programs. By regionalwe mean programs that recognize the importance ofprocesses that occur on larger geographic scales andthat cut across more than one ecosystem component. Theframework helps visualize functional relationshipsamong qualitative ingredients such as public concernsand more concrete details such as individual dataelements. It portrays the flow of information amongthe components of a regional program and ties eachaspect of the program to management decision-makingneeds. This makes it easier, during the planningprocess, to ensure that monitoring will actuallyproduce useful information. Further, the frameworksnovel, graphically oriented, and readily accessibleformat makes key information equally available to thewide range of participants (regulators, scientists,managers, public) whose input and support arenecessary for program success.     

Routine Measurement of Dissolved Inorganic 15N in Precipitation and Streamwater

The difficulty of measuring 15N in dilute solutions has limited the potential of ecosystem labeling experiments and model comparisons. By concentrating the N from large (up to 20 L) water samples on ion-exchange resin columns, we obtained enough N for accurate and reproducible 15N measurement using the Teflon tape diffusion method. Analysis of standards demonstrated >95% recovery of inorganic N from samples, and 15N values comparable to those obtained using standard distillation methods. The value of the blank at our laboratory was 0.16 moles N. Analytical precision was within 2 15N when samples of streamwater from the Bear Brook Watersheds (1800 eq · ha-1 · yr-1 N addition at 192 15N) were kept frozen until analysis. The analytical process is lengthy, but once set up can easily be performed for large numbers of samples.     

An evaluation of benthic macroinvertebrate biomass methodology

This study shows that biological assessments of water quality status using biomass estimates of wet, dry, and ash-free dry weights and counts of individual organisms from a small, headwater stream in southwestern Ohio provide essentially similar results concerning the impact of a sewage treatment plant discharge. Of the indices of biotic status for the stream segment employed for data evaluation; Diversity Index (D), Community Diversity Index (d), Trophic Condition Index (TCI), and Empirical Biotic Index (EBI), the latter two provided evaluations most consistent with benchmark water chemistry and physics information concerning the trophic status of the stream. In addition, the percent composition of macro-invertebrate taxa by pollutional category; clean water, facultative, and pollution tolerant, as ascribed using TCI and EBI ranges for individual taxa collected in combination of Ekman grab, rock-filled basket sampler and drift net samples, proves adequate for interpretation of biotic status.     

Influence of aluminium on the restoration potential of a terrestrial vascular plant,Portulaca Oleracea L. as a biomonitoring tool of fresh water aquatic environments

In the present study, the influence of aluminium on the regeneration potential of leaf and stem-cuttings of Portulaca oleracea was studied in order to identify a terrestrial plant species as an alternate biomonitoring toolof fresh water environment. The leaves and stem cuttings of theterrestrial plant, P. oleracea grew well in the distilled water producing adventitious and lateral roots. The aluminium treated leaves and stem cuttings showed a reduction in the growthof the adventitious and lateral roots and increase in the decay of leaves and stem cuttings with increasing aluminium concentration. The tolerance index calculated for the leaves and the stem cuttings showed that the leaves were more sensitivethan stems to aluminium. Since all the parameters studied showedconcentration dependent changes, the terrestrial plant, P. oleracea can be considered a suitable biomonitoring tool of fresh water environment besides its usage in the Al toxicity testing.