The present paper deals with an extensive review of literature concerning the platinum group elements (PGEs), and their impact on the environment. The increased number of cars and vehicles fitted with catalytic converters, has been linked with the wide spread in the environment of the PGEs, i.e. Pt, Pd and Rh. Numerous studies present compelling evidence that the catalytic converters, do not only minimize the pollution caused by the car exhaust fumes, but also they release in the environment particulate matter containing the above noble elements, which accumulate in the soil, and plants, or remain suspended in the air, being transported to large distances. Indeed, the concentration of these noble elements in the soil and plants has increased significantly during the last 10-15 years, especially along the road side of high ways. Assessment of the PGEs health risk was originally based on measuring the body fluid in Pt, Pd and Rh content of occupationally involved people, as well as of the general population. Recent results based on cellular studies show that the PGEs are related to respiratory sensitization, allergic reactions, dermatitis, urticaria, damage of the epithelial lung cells, asthma, rhinoconjuctivitis, lymphocyte proliferation and cytokine release and possibly to cancer. In spite of the progress attained, more work is necessary for an accurate health risk assessment.

Many management strategies to improve the health of Chesapeake Bay focus on reducing losses of sediments and nutrients from agricultural land. Plot-scale studies have suggested that Best Management Practices (BMPs) reduce these losses, and natural resource managers have since supported implementation of a variety of BMPs on farms in the Chesapeake Bay watershed over the last two decades. As a test of the efficiency of these BMPs at the watershed scale, all farms within German Branch watershed had BMPs implemented in the early 1990s. Using water quality from two past monitoring programs (i.e., in 1986 and 1991-1995) and current water quality monitoring (i.e., collected 2003-2006), we detected a 28% decrease in baseflow P concentrations a decade after BMP implementation. There were no significant changes in nitrate or total nitrogen concentrations between BMP implementation and the most recent sampling. However, the significant rate of increase (~0.08 mg N L⁻¹ year⁻¹) from 1986 to the 1990s did not continue to 2003-2006 baseflow conditions, which suggests that BMPs may have suppressed the rate of increase in nitrogen observed earlier in German. These data suggest that other management practices that increase agricultural N losses and natural processes that attenuate N losses at the watershed scale may obscure significant N reductions by current BMPs in the watershed.

Effluents from petroleum refineries contain a diverse range of pollutants including heavy metals. They also contain oil and grease, phenols, sulphides, dissolved solids, suspended solids and BOD-bearing materials. An overview of heavy metal removal from industrial effluents with emphasis on biological methods is given. Results of studies to remove heavy metals in effluents from a petroleum refinery by water hyacinth were presented. Limited success has been demonstrated for the case of iron and zinc, but further work needs to be done. There is a need to strike the right balance between the possible amount of uptake of heavy metal ions and the tendency to suffocate the ecosystem through the depletion and reduction of light and dissolved oxygen. Similarly there is a need for better understanding of the process of enhancement of the capability the water hyacinth to uptake heavy metal ions before the on-set of toxic accumulation.

Bivalve mussels can concentrate pollutants which, in high amounts, can cause cellular, physiological and behavioral changes. The gill mucus is essential for many metabolic and behavioral procedures on marine mussels including the response to environmental pollution. The present work analyzed the mucous cell number in Mytella falcata gill filaments from three sites of Santos estuary (Brazil) with different levels of sediment contamination named as sites A, B, and C. Site A is located at a low impacted region of the estuary, and sites B and C are under influence of port activities, domestic sewage, and industries like a still mill located in front of site C (the most contaminated area with high amounts of polycyclic aromatic hydrocarbons). An increase in mucous cell number was detected in animals from sites B and C, when compared to site A; this increase occurred preferentially in the frontal zone and was related to sediment contamination. Mucous cell analysis can be used as an efficient biomarker. It is suggested that mucus produced in lateral and abfrontal zones is responsible for eliminating pollutants previously absorbed and mucus produced in frontal zone is responsible for pollutant arrest and elimination as pseudofeces.

Annually, sawmills and other wood-processing factories generate a significant amount of scrap materials which are sent to landfills or incinerated. The amount of residue generated in Australia annually is estimated at 200,000 tonnes. A research project conducted at RMIT University explored utilizing these waste materials as particleboard furnish. The research team has now established a methodology for making particleboard in the laboratory using 100% hardwood sawmill residues, developing a particleboard product made in the laboratory which has acceptable mechanical properties and density profiles in accordance with the Australian Standards. However, this board product has some perceived issues which have been hindering ready commercial uptake. The current product requires a 10% higher resin load, has a 10% higher board density, and requires 10% longer pressing times compared to normal softwood particleboard. The paper presents an analysis of the current production process of particleboard to investigate the economic feasibility of particleboard production using hardwood sawmill residues. A major challenge in the analysis is converting the environmental benefit of utilizing large quantities of sawmill residue to a monetary term. Investigation of the global impact of particleboard by considering emission of carbon dioxide to the atmosphere is also included. A comparison is presented between different methods of disposing wood residues to understand the environmental benefit of using hardwood residue in particleboard.

A comprehensive study on biodiversity and environmental characteristics of three different selected study sites located on different estuarine networks viz. Matla, Saptamukhi, and Hooghly on eastern, central, and western regions, having different environmental features of Sundarbans Mangrove Ecosystem, India, a World Heritage Site, was conducted through six seasons of consecutive 2 years. The different sites understudy have shown variable species composition. Special emphasis was made to record the population structure of benthic fauna, which exhibited maximum density during pre-monsoon followed by monsoon and post-monsoon. Physicochemical parameters displayed a wide range of fluctuation through different seasons and also revealed differences among different study sites. Biotic community structures of different study sites have been analyzed using different community indices like similarity index, dominance index, diversity index, and evenness index. Moreover, in order to evaluate the environmental stress on the environmental health of this dynamic mangrove ecosystem of global importance, species pollution value and community pollution value have been deduced as a new model of biotic indices based on the distribution patterns of both zooplanktons and benthic fauna. Canonical correspondence analysis revealed the cumulative influence of a group of environmental parameters on the abundance of different components of biodiversity. The study site II (Saptamukhi), encircled by undisturbed mangrove islands, revealed the least pollution stress and higher biological diversity followed by Jharkhali (study site I), which is in the process of eco-restoration and Bokkhali (study site III), which has been under anthropogenic stress especially from ecotourism.

Mesostructured iron oxyhydroxide (FeO x ) and iron oxyhydroxide-phosphate (FeO x P) composites were organized using dodecylsulfate surfactant as a template. X-ray diffraction studies depicted a lamellar structure of the product. Ion exchange and solvent extraction methods were employed for the removal of the surfactant. Carboxylate ions exchanged lamellar type mesostructured material reorganized to a wormhole-like mesoporous material when heated under N₂ atmosphere. Surfactant was completely removed by carboxylate ions as observed by the Fourier transform infrared spectra. High surface area acetate-exchanged FeO x (230 m² g⁻¹) was obtained after the surfactant removal from the composite (2.8 m² g⁻¹). Surface area of acetate-exchanged FeO x P was the highest (240 m²g⁻¹) after the removal of the surfactant. Local structure of iron species of FeO x was investigated by X-ray absorption fine structure spectroscopy. Further, Fe···Fe bond appeared at 3.21-3.25 Å with coordination number 2-3, showing a high degree of un-saturation of Fe···Fe bonds. As compared with bulk iron oxyhydroxide and iron-intercalated montmorillonite, the mesoporous iron materials were highly effective for arsenic removal from low concentrations of aqueous solutions. Furthermore, mesoporous iron materials were stable in aqueous phase.

Hydrophobic modified vermiculite mixed with soil was investigated in biodegradation experiments of naphthalene and anthracene. The experiments had been carried out on mixtures of soil and vermiculite at a proportion of 2%, 10%, and 15% and also in the absence of clay used for control. Biodegradation of the pollutants was followed by the decline of naphthalene and anthracene concentration, measured by CG. Compound mineralization was also proved by the evolution of CO₂. The results showed that in the mixture with a higher proportion of vermiculite biodegradation is enhanced compared to that performed in the absence of vermiculite. In general, when vermiculite proportions are increased, the rate of degradation increases, which may account for the bioavailability of compounds. Bioavailability is an important factor for the degradation of compounds with low solubility. Comparison of biodegradation rates shows that naphthalene is degraded faster than anthracene. The chemical structure could be responsible for this observation. However, although we did not identify the microorganism that was in the soil, we can conclude that vermiculite could be an alternative for the bioavailability of such compounds. Vermiculite in the modified form could also be very useful as a barrier to retain organic pollutants in accidental spills.

In the greenhouse and container nursery production industry there is potential for runoff of nitrogen (N) and phosphorus (P), which may contaminate surface and groundwater. Since the 1950s constructed wetlands (CWs), as a simple, low-technology method, have been shown to effectively treat agricultural, industrial, and municipal wastewater. We investigated the N and P attenuating potential of three floating hydrophytes planted in a laboratory-scale subsurface flow (SSF) CW system. Over an 8-week period plants were supplied with N and P (0.39 to 36.81 mg·L⁻¹ N and 0.07 to 6.77 mg·L⁻¹ P) that spanned the rates detected in nursery runoff between the discharge and inflow locations of a commercial nursery currently employing CWs. Whole plant dry weight was positively correlated with N and P supplied. Highest N recovery rates were exhibited by water hyacinth (Eichhornia crassipes [Mart.] Solms.) and water lettuce (Pistia stratiotes L.). P recovery rates were similar for water hyacinth, water lettuce, and dwarf redstemmed parrotfeather (Myriophyllum aquaticum [Vell.] Verdc.). These floating hydrophytes can be cultivated in a SSF CW to remediate runoff losses of N and P. The possibility exists for integrating them into a polycultural remediation system that includes emergent aquatic macrophytes for processing and polishing nursery/greenhouse wastewater.

The effects of bentazon and molinate, two selective herbicides recommended for integrated weed management in rice, were studied in Anabaena cylindrica, an abundant cyanobacterium isolated from a Portuguese rice field agro-ecosystem. Comparative effects of both herbicides on A. cylindrica were estimated under laboratory conditions by measuring its dry weight yield, photopigments, and carbohydrate and protein contents in a time- and dose-dependent exposure throughout 72 h. Photosynthesis and respiration were also monitored. The results revealed that both herbicides exerted a pleiotropic effect on the cyanobacterium at the range of concentrations tested (0.75-2 mM). Growth, chlorophyll a, carotenoids and phycobiliproteins were more adversely affected by molinate than by bentazon. Cyanobacterial growth inhibitions of over 50% were observed after 48 h when 1.5-2 mM of molinate were applied. Bentazon concentrations ranging from 0.75 to 2 mM did not significantly modified chlorophyll a content with time, however, considerable reductions in chlorophyll a, carotenoids and specially phycobiliproteins were observed with molinate. Protein content increased with both herbicides although the effect was particularly noticeable with the highest concentration of molinate. Herbicide effects on carbohydrate content were contrasting: molinate increased this organic fraction whereas bentazon decrease it. Photosynthesis and respiration were inhibited by both herbicides and higher molinate concentrations (1.5-2 mM) completely ceased O₂ evolution after 48 h. Since A. cylindrica is abundant in Portuguese rice fields and could be used as an inoculum source in rice biofertilization programs, their protection from potential residual effects of herbicides is fundamental for a correct management of local soil fertility.