Two methods to determine plant responses to pollutant mixtures

Two methods are described which enable better interpretation of the effects of pollutant mixtures on plants. The first method is a statistical procedure in which treatment components are partitioned into single degrees of freedom comparisons. With this technique, joint action of pollutants can be calculated. Trends in response, such as linear or quadratic, can be observed for quantitative data. Also, the nature of interactions in experiments of a factorial design can be determined. The second procedure described is growth analysis. Growth analysis provides a method for determination of the effects of pollutants on physiological processes, such as relative rates of growth, carbon allocation and leaf expansion. Advantages, disadvantages and applications of both methods are discussed.     

A Collaborative Effort to Model Plant Response to Acidic Rain

Radish plants were exposed three times per week to simulated acidic rain at pH values of 2.6 to 5.4 over the course of four weeks in trials performed at Argonne, Illinois; Ithaca and Upton, New York; Corvallis, Oregon; Oak Ridge, Tennessee; and Toronto, Canada. Uniform genotype, soil media and planting techniques, treatment procedures, biological measurements, and experimental design were employed. Growth of plants differed among trials as a result of variation in greenhouse environmental conditions according to location and facilities. Larger plants underwent greater absolute but lower relative reductions in biomass after exposure to the higher levels of acidity. A generalized Mitscherlich function was used to model the effects of acidity of simulated rain or dry mass of hypocotyls using data from three laboratories that performed duplicate trials. The remaining data, from three other laboratories that performed only one trial each, were used to test the model. When the laboratory by trial effect was removed (influence of different growth. conditions), lack of fit to the Mitscherlich function was insignificant. Thus, a single mathematical model satisfactorily characterized the relationship between acidity and mean plant response. The pH value associated with a 10 percent reduction in mass was 3.3 ± 0.3 for hypocotyls. No value was estimated for shoots because effects oh shoots were not significant. The results of this study demonstrate that a generalized exposure-response model can be developed in the presence of large variations in environmental conditions when plant culture and exposure to simulated rain are standardized among laboratories.     

From Valuation to Governance: Using Choice Experiment to Value Street Trees

This paper reports a choice experiment used to estimate the value of street trees in the city center of Lodz, Poland, and the broader context of how valuation results helped to improve governance of urban ecosystem services in this city. Based on a simplified inventory of trees, we prepared a set of hypothetical programs which put varying emphasis on the different ways to increase the numbers of trees, along with different levels of a hypothetical tax that would have to be paid by respondents to implement a given program. Our study indicated that the 351 surveyed Lodz residents were willing to pay the highest price for greening those streets where currently there are few or no trees and confirmed the general importance of planting trees. The results provided an argument in the debate on the new development strategy for the city and helped to promote the concept of ecosystem services.     

Back to Basics

ABSTRACT

Tests of the compatibility of geomembrane (GM) samples with waste were conducted using U.S. Environmental Protection Agency (EPA) Method 9090 and the Comprehensive Testing System (CTS). The CTS is a multi-axial performance test capable of simultaneous cyclic mechanical loads and chemical exposure. The test chemicals consisted of solvents, transportation-related compounds, and synthesized landfill leachate. Method 9090 testing was unable to distinguish between the effects of individual chemicals to which the GM was subjected, while the CTS was able to provide statistically-significant differences that were also traceable to chemical properties of the solvent and the GM liner. Further, the time required for changes in mechanical properties of the GM was significantly shorter than would be expected based upon diffusion of the solvent into the GM alone. The combination of chemical attack with mechanical load was found to enhance both reduction in mechanical properties and the ability of the solvent to diffuse into the GM. The CTS is a more realistic test than the existing standard test methods because of its ability to provide multi-axial loads and chemical exposure simultaneously.     

Reconnecting to the Biosphere

Humanity has emerged as a major force in the operation of the biosphere, with a significant imprint on the Earth System, challenging social-ecological resilience. This new situation calls for a fundamental shift in perspectives, world views, and institutions. Human development and progress must be reconnected to the capacity of the biosphere and essential ecosystem services to be sustained. Governance challenges include a highly interconnected and faster world, cascading social-ecological interactions and planetary boundaries that create vulnerabilities but also opportunities for social-ecological change and transformation. Tipping points and thresholds highlight the importance of understanding and managing resilience. New modes of flexible governance are emerging. A central challenge is to reconnect these efforts to the changing preconditions for societal development as active stewards of the Earth System. We suggest that the Millennium Development Goals need to be reframed in such a planetary stewardship context combined with a call for a new social contract on global sustainability. The ongoing mind shift in human relations with Earth and its boundaries provides exciting opportunities for societal development in collaboration with the biosphere--a global sustainability agenda for humanity.     

Using Farmers’ Actions to Measure Crop Loss Due to Air Pollution

The effects of ozone on the profitability of Illinois cash grain farms is investigated by utilizing a profit function framework. This approach uses individual farms as the observational unit so the data are generated under field conditions. Hence, experimental plot data are not used although results from past biological experiments are utilized to frame initial hypotheses and for evaluation of the estimated model. This study demonstrates the benefits of combining economic data and biological science results to estimate the economic reactions of producers in terms of input and output (production) response to an ambient environmental characteristic.

A time series of cross sectional data on cash grain farms in Illinois is used to estimate two profit functions. Ozone data are measured on a growing season basis by county. The estimated model shows ozone has a negative effect on profits. Increases in ozone levels tend to depress output levels and lessen the demand for variable inputs. Additionally, a production function is derived from one of the profit functions. The impact of ozone is found to be in general agreement with dose-response data obtained in Illinois by plant scientists.     

Letters to The Editor

Abstract

Since 1990, basic knowledge of the “chemical climate” of fine particles, has greatly improved from Junge’s compilation from the 1960s. A worldwide baseline distribution of fine particle concentrations on a synoptic scale of approximately 1000 km can be estimated at least qualitatively from measurements. A geographical distribution of fine particle characteristics is deduced from a synthesis of a variety of disparate data collected at ground level on all continents, especially in the northern hemisphere. On the average, the regional mass concentrations range from 1 to 80 μg/m³, with the highest concentrations in regions of high population density and industrialization. Fine particles by mass on a continental and hemispheric spatial scale are generally dominated by non-sea salt sulfate (0.2 to ～20 μg/m³, or ～25%) and organic carbon (0.2->10 μg/m³, or ～25%), with lesser contributions of ammonium, nitrate, elemental carbon, and elements found in sea salt or soil dust. The crustal and trace metal elements contribute a varied amount to fine particle mass depending on location, with a larger contribution in marine conditions or during certain events such as dust storms or volcanic disturbances. The average distribution of mass concentration and major components depends on the proximity to areal aggregations of sources, most of which are continental in origin, with contributions from sea salt emissions in the marine environment. The highest concentrations generally are within or near very large population and industrial centers, especially in Asia, including parts of China and India, as well as North America and Europe. Natural sources of blowing dust, sea salt, and wildfires contribute to large, intermittent spatial-scale particle loadings beyond these ranges. A sampling of 10 megacities illustrates a range of characteristic particle composition, dependent on local and regional sources. Long-range transport of pollution from spatially aggregated sources over hundreds of kilometers creates persistent regional- and continental-scale gradients of mass concentration, sulfate, and carbon species especially in the northern hemisphere. Data are sparse in the southern hemisphere, especially beyond 45° S, but are generally very low in mass concentrations.     

Basement Ventilation Needed to Lower Indoor Radon to Acceptable Levels

Although many remedial measures have been proposed for excessive Indoor ²²²Rn concentrations, their general effectiveness in given situations is not well established, In part because of the number and complexity of the factors that influence Indoor ²²²Rn. The strategy considered here is the use of basement ventilation to control upstairs Indoor radioactivity. A simple two-compartment model is described and used to derive ventilation rates that are needed to lower radon concentrations to specified levels. Previously published indoor radon measurements are used to derive the parameters needed for the calculations. The results of the two compartment model differ typically by a factor of two from the simpler, more often used one-compartment approximation.     

The contribution of particles washed from rooftops to contaminant loading to urban streams

Rooftops are both a source of and a pathway for contaminated runoff in urban environments. To investigate the importance of particle-associated contamination in rooftop runoff, particles washed from asphalt shingle and galvanized metal roofs at sites 12 and 102 m from a major expressway were analyzed for major and trace elements and PAHs. Concentrations and yields from rooftops were compared among locations and roofing material types and to loads monitored during runoff events in the receiving urban stream to evaluate rooftop sources and their potential contribution to stream loading. Concentrations of zinc, lead, pyrene, and chrysene on a mass per mass basis in a majority of rooftop samples exceeded established sediment quality guidelines for probable toxicity of bed sediments to benthic biota. Fallout near the expressway was greater than farther away, as indicated by larger yields of all contaminants investigated, although some concentrations were lower. Metal roofing was a source of cadmium and zinc and asphalt shingles a source of lead. The contribution of rooftop washoff to watershed loading was estimated to range from 6 percent for chromium and arsenic to 55 percent for zinc. Estimated contributions from roofing material to total watershed load were greatest for zinc and lead, contributing about 20 and 18 percent, respectively. The contribution from atmospheric deposition of particles onto rooftops to total watershed loads in stormwater was estimated to be greatest for mercury, contributing about 46 percent.     

Performance of RBC coupled to a polyurethane foam to biodegrade petroleum refinery wastewater

Biological treatment of petroleum refinery wastewater was studied in a rotating biological contactor (RBC) coupled to a polyurethane foam (PUF) as a porous biomass support. The PUF was attached on both sides of biodisks. The biodegradation studies were carried out at varying hydraulic and organic loadings. COD removal efficiency of up to 87% was achieved. The results obtained in terms of biodegradation of COD, NH3-N, phenol, hydrocarbons and suspended solids in this study were compared with those in the literature. The RBC-PUF bioreactor was found to have a better performance than a conventional RBC for the biodegradation of the above mentioned parameters. A higher concentration of active biomass (77 g TVS/m2) was observed in the RBC-PUF as compared to other treatment systems. A linear relationship between COD applied and COD removed was observed for the combined four stage system as well as for the individual stages.     

Household hazardous waste disposal to landfill: using LandSim to model leachate migration

Municipal solid waste (MSW) landfill leachate contains a number of aquatic pollutants. A specific MSW stream often referred to as household hazardous waste (HHW) can be considered to contribute a large proportion of these pollutants. This paper describes the use of the LandSim (Landfill Performance Simulation) modelling program to assess the environmental consequences of leachate release from a generic MSW landfill in receipt of co-disposed HHW. Heavy metals and organic pollutants were found to migrate into the zones beneath a model landfill site over a 20,000-year period. Arsenic and chromium were found to exceed European Union and US-EPA drinking water standards at the unsaturated zone/aquifer interface, with levels of mercury and cadmium exceeding minimum reporting values (MRVs). The findings demonstrate the pollution potential arising from HHW disposal with MSW.     

Potential of microalgae as biopesticides to contribute to sustainable agriculture and environmental development

The loss of yields from agricultural production due to the presence of pests has been treated over the years with synthetic pesticides, but the use of these substances negatively affects the environment and presents health risks for consumers and animals. The development of agroecological systems using biopesticides represents a safe alternative that contributes to the reduction of agrochemical use and sustainable agriculture. Microalgae are able to biosynthesize a number of metabolites with potential biopesticidal action and can be considered potential biological agents for the control of harmful organisms to soils and plants. The present work aims to provide a critical perspective on the consequences of using synthetic pesticides, offering as an alternative the biopesticides obtained from microalgal biomass, which can be used together with the implementation of environmentally friendly agricultural systems.     

A new flux-orientated concept to derive critical levels for ozone to protect vegetation

The current European critical levels for ozone (O3) to protect crops, natural and semi-natural vegetation and forest trees are based on a relative small number of open-top chamber experiments with a very limited number of plant species. Therefore, the working group "Effects of Ozone on Plants" of the Commission on Air Pollution Prevention of the Association of German Engineers and the German Institute of Standardization reanalysed the literature on O3 effects on European plant species published between 1989 and 1999. An exposure-response relationship for wild plant species and agricultural crops could be derived from 30 experiments with more than 30 species and 90 data points; the relationship for conifer and deciduous trees is based on 20 experiments with nine species and 50 data points. From these relationships maximum O3 concentrations for different risk stages are deduced, below which the vegetation type is protected on the basis of the respective criteria. Because it is assumed that the fumigation concentrations reflect the O3 concentrations at the top of the canopy, i.e. the upper surface boundary of the quasi-laminar layer if the micrometeorological big-leaf approach is applied, the application of these maximum O3 concentrations requires the transformation of O3 concentrations measured at a reference height above the canopy to the effective phytotoxic concentrations at the top of the canopy. Thus, the approach described in this paper is a synthesis of the classical concept of toxicology of air pollutants (critical concentrations) and the more toxicological relevant dose concept.     

Modeling to Evaluate Contribution of Oil and Gas Emissions to Air Pollution

Oil and gas production in the Western United States has increased considerably over the past 10 years. While many of the still limited oil and gas impact assessments have focused on potential human health impacts, the typically remote locations of production in the Intermountain West suggests that the impacts of oil and gas production on national parks and wilderness areas (Class I and II areas) could also be important. To evaluate this, we utilize the Comprehensive Air quality Model with Extensions (CAMx) with a year-long modeling episode representing the best available representation of 2011 meteorology and emissions for the Western United States. The model inputs for the 2011 episodes were generated as part of the Three State Air Quality Study (3SAQS). The study includes a detailed assessment of oil and gas (O&G) emissions in Western States. The year-long modeling episode was run both with and without emissions from O&G production. The difference between these two runs provides an estimate of the contribution of the O&G production to air quality. These data were used to assess the contribution of O&G to the 8 hour average ozone concentrations, daily and annual fine particulate concentrations, annual nitrogen deposition totals and visibility in the modeling domain. We present the results for the Class I and II areas in the Western United States. Modeling results suggest that emissions from O&G activity are having a negative impact on air quality and ecosystem health in our National Parks and Class I areas.

Implications: In this research, we use a modeling framework developed for oil and gas evaluation in the western United States to determine the modeled impacts of emissions associated with oil and gas production on air pollution metrics. We show that oil and gas production may have a significant negative impact on air quality and ecosystem health in some national parks and other Class I areas in the western United States. Our findings are of particular interest to federal land managers as well as regulators in states heavy in oil and gas production as they consider control strategies to reduce the impact of development.     

Deposition of ozone to a mature spruce forest: measurements and comparison to models

Removal of ozone at terrestrial surfaces provides a major sink for tropospheric ozone and, therefore, a constraint on the peak concentrations achieved during photochemical episodes. This study reports results from 5 years of almost continuous measurements of vertical profiles of ozone and related meteorological variables over a mature spruce forest in Bavaria. Deposition velocities calculated from flux/gradient and eddy correlation flux measurements have been compared with estimates based on a resistance model and yield satisfactory agreement during fine weather conditions. The results also suggest that biogenic emissions of reactive hydrocarbons from the forest influence the vertical profile of ozone.     

Local to regional emission sources affecting mercury fluxes to New York lakes

Lake-sediment records across the Northern Hemisphere show increases in atmospheric deposition of anthropogenic mercury (Hg) over the last 150 years. Most of the previous studies have examined remote lakes affected by the global atmospheric Hg reservoir. In this study, we present Hg flux records from lakes in an urban/suburban setting of central New York affected also by local and regional emissions. Sediment cores were collected from the Otisco and Skaneateles lakes from the Finger Lakes region, Cross Lake, a hypereutrophic lake on the Seneca River, and Glacial Lake, a small seepage lake with a watershed that corresponds with the lake area. Sediment accumulation rates and dates were established by ²¹⁰Pb. The pre-anthropogenic regional atmospheric Hg flux was estimated to be 3.0 μg m⁻² yr⁻¹ from Glacial Lake, which receives exclusively direct atmospheric deposition. Mercury fluxes peaked during 1971–2001, and were 3 to more than 30 times greater than pre-industrial deposition. Land use change and urbanization in the Otisco and Cross watersheds during the last century likely enhanced sediment loads and Hg fluxes to the lakes. Skaneateles and Glacial lakes have low sediment accumulation rates, and thus are excellent indicators for atmospheric Hg deposition. In these lakes, we found strong correlations with emission records for the Great Lakes region that markedly increased in the early 1900s, and peaked during WWII and in the early 1970s. Declines in modern Hg fluxes are generally evident in the core records. However, the decrease in sediment Hg flux at Glacial Lake was interrupted and has increased since the early 1990s probably due to the operation of new local emission sources. Assuming the global Hg reservoir tripled since the pre-industrial period, the contribution of local and regional emission sources to central New York lakes was estimated to about 80% of the total atmospheric Hg deposition.     

An introduction to critical loads

The critical loads approach to emission controls of gaseous pollutants is a concept with a short but eventful history. Despite difficulties with definitions and agreed values, its acceptance within the UN-ECE Convention on Long Range Transboundary Air Pollution has provided the impetus for developing methods to put critical loads to a practical use-the revision of the UNECE emission protocols for sulphur and nitrogen. Methodologies first focus upon quantifying a pollutant threshold at which harmful effects occur on particular sensitive receptors (usually biological species). This threshold is known as the critical load for deposited pollutants, and as the critical level for gaseous pollutants acting on receptors. To calculate a critical load, biological effects are usually 'translated' to critical chemical values, e.g. harmful effects on fish 'translate' to alkalinity or aluminium concentrations in water; thus, critical load calculations may be based upon the chemistry of a system. Such calculations may be performed using simple, steady-state models, whilst the use of more complex, dynamic models provides an insight into the past and future trends. Maps of critical loads can be drawn using calculated values, and maps of pollutant deposition data will then show geographical areas where critical loads are exceeded. Spatial emission-deposition models can identify sources contributing to areas of excess loads and quantify necessary emission reductions. Optimization procedures applied to such models can derive abatement strategies related to economic costs and critical load effects. The critical load calculations may also be used to underpin the setting of target loads; these are pollutant loads, determined by political agreement, which take account of social, economic and political considerations.     

Adaptation to environmental stress in Daphnia magna simultaneously exposed to a xenobiotic

In standardized ecotoxicological testing chemicals are investigated under optimal conditions for the test organisms despite the fact that environmental factors such as predation pressure and food availability are important parameters regulating natural populations. Food limitation and predator presence can induce shifts in life-history traits in various Daphnia species, especially trade-offs in reproductive biomass allocation. These adaptive responses are thought to ensure survival of the population in a highly variable environment. A xenobiotic dispersant (used in textile dyeing processes) also shifted the biomass allocation of Daphnia magna. To assess whether the dispersant could hinder D. magna adaptation to varying environmental conditions, we conducted experiments with food level and presence of Chaoborus larvae as environmental factors and simultaneous exposure to the dispersant. At low food level and in presence of the predator, D. magna produced fewer but larger sized neonates, regardless of dispersant exposure. The dispersant shifted biomass allocation towards more but smaller sized offspring in all experiments. However, the adaptive response to the environmental factors and the dispersant effect cancelled each other out in that they induced independently from each other opposite shifts in biomass allocation. In summary, the dispersant exposure resulted not in an inhibition of the adaptive response but in a reduction of the value of the response. Our study with this model substance demonstrates that xenobiotics can affect the adaptation of organisms to environmental stress which can result in effects likely to be overlooked in standardized testing.     

Mice exposure to tannery effluents changes their olfactory capacity,and their response to predators and to the inhibitory avoidance test

Environmental Science and Pollution Research - The current study has assessed whether the oral and/or dermal exposure of C57Bl/6 J mice to tannery effluent (a complex pollutant consisting of...     

Tolerance to agricultural pesticides of strains belonging to four genera of Rhizobiaceae

In order to determine their tolerance to pesticides, 122 strains of rhizobia isolated from different geographical regions, and belonging to the genera Rhizobium, Mesorhizobium, Sinorhizobium and Bradyrhizobium were tested against eight herbicides, four fungicides and five insecticides. Sensitivity to the pesticides was measured by using the filter paper disk method at four concentrations, 0.45, 4.5, 45 and 450 μg per disk. When the pesticides were used at 0.45 μg per disk, a concentration similar to that found when pesticides are applied under field conditions, no inhibition was observed. Strains growth was affected at concentrations of 45 and 450 μg pesticide per disk. These higher concentrations can be encountered when seeds are treated with pesticides. Pesticides tolerance level was correlated to pesticide function, i.e rhizobial strains were more tolerant to insecticides, followed by herbicides and then fungicides. Two fungicides, captan and mancozeb, inhibited the highest number of strains. Only one insecticide, carbaryl, affected the growth of some rhizobial strains. Strains isolated from the arctic (Mesorhizobium spp. and R. leguminosarum bv. viciae), a putative pesticides-free environment, were either less or equally affected by pesticides compared to strains isolated from agricultural regions.