Resistivity of plastic litter to chemical weathering, mechanical erosion, and biological degradation poses a critical environmental threat. Plastic debris has increased in abundance over the past several decades along shorelines and at sea, where organisms mistake small particles including plastic pellets as a potential food supply. These pellets have been shown to adsorb persistent organic pollutants such as PCBs, which may endanger the organism and become ingested higher in the food chain. Although several studies have been conducted to determine the amount and effects of plastics pollution in marine environments, relatively little is known concerning fresh water plastics pollution. This study represents the first detailed examination of the distribution, types, and physical and chemical degradation processes of plastic particles in a fresh water setting. In conducting field surveys along the shoreline of Lake Huron, Canada, we were able to ascertain that the total number of pellets over multiple sampling localities comprise 94% of plastic debris. The majority of the pellets were found proximal to an industrial sector along the southeastern margin of the lake and their abundance steadily decreased northward, following the dominant lake current patterns. Laboratory analyses using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy indicate predominant mechanical abrasion textures, including grooves, gauges, pits, and flakes, and less common chemical weathering features such as linear and crescentic fractures that developed from shrinkage during subaerial exposure. The predominant type of plastic, polyethylene, appears to be much more resistant to chemical weathering than polypropylene, as indicated by oxidation peaks on FTIR spectra suggesting that polypropylene degrades more readily under natural conditions on freshwater beaches.

Granular bentonite has been assessed regarding its capacity to remove Hg(II), Cd(II) and Pb(II) from aqueous solutions. Sorption capacities, kinetics and the dependence of the sorption process on pH were determined. Fractional power, pseudo-first-order, pseudo-second-order and intra-particle diffusion equations were used to model the kinetics of metal adsorption. The pseudo-second-order model showed the best fit to experimental data. Different two-parameter sorption isotherm models (Langmuir, Freundlich, Temkin and Dubinin–Radushkevich) were used to fit the equilibrium data. Freundlich's isotherm model gave the best fit to experimental data. The selectivity of granular bentonite towards these metals is Pb(II) > Cd(II) > Hg(II). The adsorption capacities of granular bentonite towards the metals expressed in milligramme metal per gramme granular bentonite are 19.45, 13.05 and 1.7 for Pb(II), Cd(II) and Hg(II), respectively (for an initial concentration of 100 mg metal/L).

The presented study deals with the interpretation of soil quality monitoring data using hierarchical cluster analysis (HCA) and principal components analysis (PCA). Both statistical methods contributed to the correct data classification and projection of the surface (0–20 cm) and subsurface (20–40 cm) soil layers of 36 sampling sites in the region of Burgas, Bulgaria. Clustering of the variables led to formation of four significant clusters corresponding to possible sources defining the soil quality like agricultural activity, industrial impact, fertilizing, etc. Two major clusters were found to explain the sampling site locations according to soil composition—one cluster for coastal and mountain sites and another—for typical rural and industrial sites. Analogous results were obtained by the use of PCA. The advantage of the latter was the opportunity to offer more quantitative interpretation of the role of identified soil quality sources by the level of explained total variance. The score plots and the dendrogram of the sampling sites indicated a relative spatial homogeneity according to geographical location and soil layer depth. The high-risk areas and pollution profiles were detected and visualized using surface maps based on Kriging algorithm.

Industries on the island of Mauritius are under increasing pressure from the regulatory authority and from the general public to control the air pollution from their boilers and particularly that of sulfur dioxide emissions from fuel oil combustion. The measures taken by industry are usually “ad hoc” in nature, and there has been yet no proper scientific methodology to justify the nature of the pollution control interventions. Air modeling as a planning tool provides a scientific methodology to industries and to the regulatory authority to select the optimum option(s) among various scenarios such as raising stack heights, changing fuels, implementing cleaner production opportunities or installation of wet scrubbers. The aim of this project was to use an air dispersion model for the selection of air pollution control systems for industrial boilers in an industrial estate. Given a number of constraints on small island developing states like Mauritius, it is recommended to start using established and simple modeling methods, as the complexity of the more refined models requires a relatively long learning curve to be able to use the model correctly. The Industrial Source Complex Short Term (ISCST3) is recommended for that purpose. The application of the ISCST3 model to the multiple-source case study helped in the identification of the most cost-effective options.

In this study, a fast bioassay using the ECOTOX system to evaluate biological safety of waste water samples from different sources was performed. This biological system works full automatically to test water quality. The system uses the image analysis of movement behavior of the flagellate Euglena gracilis as a model organism. The measured parameters are cell motility, velocity, orientation (r-value, upward swimming and alignment) as well as cell form (compactness). In most tested waste samples, precision of orientation (r-value) is inhibited at concentrations which showed less effect on the other parameters. Motility and compactness were noticed to be the least inhibited parameters in response to waste water samples. The results of waste treatment plants revealed the efficiency of the used purification system. Movement as well as orientation parameters in E. gracilis showed high sensitivity toward chlorine. The order of sensitivity was motility > velocity > r-value > upward swimming with EC50 values of 0.69, 0.81, 0.85, and 1.78 mg L−1, respectively. ECOTOX with its test organism (E. gracilis) provides an automatic, fast and sensitive system to monitor water samples.

Identifying the factors responsible for the diversity of responses of biota to industrial pollution is crucial for predicting the fates of polluted ecosystems. A meta-analysis based on 49 field studies conducted around 47 point polluters demonstrated that the individual (growth and reproduction) and community (abundance and species richness) characteristics of bryophytes in polluted habitats are reduced to about a half of the values observed in unpolluted sites. Non-ferrous smelters cause a stronger reduction in species richness and larger changes in species composition than other types of polluters. The magnitudes of the effects of pollution on the abundances of individual bryophyte species are not linked with their taxonomic position, life form or Ellenberg indicator values for light, moisture and nitrogen. The variation in species’ responses to pollution is mostly explained by differences in their reproductive characteristics; bryophyte species that possess special forms of vegetative reproduction and those that produce abundant sporophytes are more successful in polluted habitats. Ranking of bryophyte species according to their sensitivity to pollution is independent of the type of the polluter. Changes in bryophyte cover follow changes in tree cover, but not changes in the cover of the vascular field layer in the same pollution gradients. Pollution impacts cause stronger adverse effects on bryophytes in warmer climates.

The adsorption capacity of seven inorganic solid wastes [air-cooled blast furnace (BF) slag, water-quenched BF slag, steel furnace slag, coal fly ash, coal bottom ash, water treatment (alum) sludge and seawater-neutralized red mud] for Cd2+, Cu2+, Pb2+, Zn2+ and Cr3+ was determined at two metal concentrations (10 and 100 mg L−1) and three equilibrium pH values (4.0, 6.0 and 8.0) in batch adsorption experiments. All materials had the ability to remove metal cations from aqueous solution (fly and bottom ash were the least effective), their relative abilities were partially pH dependant and adsorption increased greatly with increasing pH. At equimolar concentrations of added metal, the magnitude of sorption at pH 6.0 followed the general order: Cr3+ ≥ Pb2+ ≥ Cu2+ > Zn2+ = Cd2+. The amounts of previously sorbed Pb and Cd desorbed in 0.01 M NaNO3 electrolyte were very small, but those removed with 0.01 M HNO3, and more particularly 0.10 M HNO3, were substantial. Water treatment sludge was shown to maintain its Pb and Cd adsorption capability (pH 6.0) over eight successive cycles of adsorption/regeneration using 0.10 M HNO3 as a regenerating agent. By contrast, for BF slag and red mud, there was a very pronounced decline in adsorption of both Pb and Cd after only one regeneration cycle. A comparison of Pb and Cd adsorption isotherms at pH 6.0 for untreated and acid-pre-treated materials confirmed that for water treatment sludge acid pre-treatment had no significant effect, but for BF slag and red mud, adsorption was greatly reduced. This was explained in terms of residual surface alkalinity being the key factor contributing to the high adsorption capability of the latter two materials, and acid pre-treatment results in neutralization of much of this alkalinity. It was concluded that acid is not a suitable regenerating agent for slags and red mud and that further research and development with water treatment sludge as a metal adsorbent are warranted.

Two cultivars of soybean (Pusa 9814 and Pusa 9712) were investigated to evaluate the impact of ambient and elevated concentrations of ozone (O3) in a suburban site of India with and without application of 400 ppm ethylenediurea (EDU) in open top chambers having filtered air (FCs), non-filtered air (NFCs), and non-filtered plus 20 ppb O3 (NFCs + 20 ppb). Significant reductions were observed in various growth parameters, biomass accumulation, and yield attributes of soybean cultivars due to ambient O3 in NFCs and elevated concentration of O3 in NFCs + 20 ppb. Reductions in all parameters were of lower magnitude in plants treated with EDU as compared to non-EDU treated plants. Yield (weight of seeds plant−1) increased by 29.8% and 33% in Pusa 9712 and by 28.2% and 29.0% in Pusa 9814 due to EDU treatment in plants grown at ambient and elevated levels of O3, respectively. The results clearly showed that (a) EDU can be effectively used to assess phytotoxicity of O3 by providing protection against its deleterious effects, (b) EDU can be used for biomonitoring of O3 in areas experiencing its higher concentrations, and (3) EDU is more effective against higher concentrations of O3.

The research presented here represents a segment of a cumulative impact assessment of resource development in northeastern British Columbia. It considers point and area source emissions of sulphur and nitrogen oxides (SO₂ and NO x , respectively), over a 2,156-km² area. With the exception of open burning, all emissions are from Upstream Oil and Gas (UOG) sector sources (SO₂, n = 103; NO x , n = 250; area, n = 25). AERMOD View™ was used to estimate the maximum potential concentration and deposition of these pollutants over 1-h, 3-h, 24-h, and annual averaging periods. Results are compared with various thresholds and limits from the policy and scientific literature to assess the potential cumulative effects of these pollutants. Of the thresholds employed, exceedances of the 1-h and 24-h NO x concentrations and the annual SO₂ concentration are predicted. There were no predicted exceedances of annual deposition thresholds (i.e., “Critical Loads”). Maximum predicted concentrations vary between compounds and are related to boundary layer stability, elevation, and distance from sources. Comparison with nearby monitoring data indicated that predicted concentrations were reasonable and that AERMOD provides a useful tool for approaching the potential cumulative impacts of air pollution from multiple sources. While the accuracy of Gaussian-based annual deposition estimates is questioned, model enhancements that could extend the application to more comprehensive assessments are suggested. Lastly, the implications of predicted threshold violations for forest ecosystems and local forest-dependent First Nations communities are discussed.

In this study, microalgae Scenedesmus quadricauda was entrapped in calcium alginate/polyvinyl alcohol composite hydrogel beads by phase-inversion techniques. The composite biosorbents were used for removal of Cu(II) and Cd(II) ions from single component and binary systems using cell-free composite beads as a control system. The effects of the experimental conditions (such as pH, initial metal ions concentrations, temperatures, contact time, and biosorbent concentrations) on Cu(II) and Cd(II) removal efficiencies were studied. The maximum metal ions on the bare and algal biomass immobilized in alginate beads were observed between pH 5.0 and 6.0. The biosorption of metal ions by the bare and composite beads increased as the initial concentration of the metal ions increased in the medium. The biosorption of Cu(II) and Cd(II) on the composite beads appears to be slightly temperature dependent. The maximum biosorptions of metal ions onto microalgae entrapped in composite beads were 0.970 ± 0.028 and 0.682 ± 0.017 mmol/g for Cu(II) and Cd(II) ions, respectively. The equilibrium experimental data for two metallic species fitted well by the Langmuir model. The values of ΔG° at all temperatures are negative, indicating the spontaneous nature of the biosorption process. When the metal ions competed (in the case of the biosorption from their mixture), the amounts of biosorption onto microalgae cells entrapped in beads were 0.857 ± 0.033 mmol/g for Cu(II) and 0.593 ± 0.024 mmol/g for Cd(II). Under noncompetitive and competitive conditions, the affinity order of ions for biosorbents was Cu(II) > Cd(II).