This study characterizes the effects of water-soil flooding volume ratio and flooding time on copper (Cu) desorption and toxicity following multiple floodings of field-collected soils from agricultural sites acquired under the Comprehensive Everglades Restoration Plan (CERP) in south Florida. Soils from four field sites were flooded with three water-soil ratios (2, 4, and 6 [water] to 1 [soil]) and held for 14 days to characterize the effects of volume ratio and flooding duration on Cu desorption (volume ratio and flooding duration study). Desorption of Cu was also characterized by flooding soils four times from seven field sites with a volume ratio of 2 (water) to 1 (soil) (multiple flooding study). Acute toxicity tests were also conducted using overlying waters from the first flooding event to characterize the effects of Cu on the survival of fathead minnows (Pimephales promelas), cladocerans (Daphnia magna), amphipods (Hyalella azteca), midges (Chironomus tentans), duckweed (Lemna minor), and Florida apple snails (Pomacea paludosa). Acute tests were also conducted with D. magna exposed to overlying water from the second and third flooding events. Results indicate that dissolved Cu concentrations in overlying water increased with flooding duration and decreased with volume ratio. In the multiple flooding study, initial Cu concentrations in soils ranged from 5 to 223 mg/kg (dw) and were similar to Cu concentration after four flooding events, indicating retention of Cu in soils. Copper desorption was dependent on soil Cu content and soil characteristics. Total Cu concentration in overlying water (Cuw) was a function of dissolved organic carbon (DOC), alkalinity, and soil Cu concentration (Cus): log(Cuw) = 1.2909 + 0.0279 (DOC) + 0.0026 (Cus) - 0.0038 (alkalinity). The model was validated and highly predictive. Most of the desorbed Cu in the water column complexed with organic matter in the soils and accounted for 99% of the total dissolved Cu. Although total dissolved Cu concentrations in overlying water did not significantly decrease with number of flooding events, concentrations of free Cu²⁺ increased with the number of flooding events, due to a decrease in DOC concentrations. The fraction of bioavailable Cu species (Cu²⁺, CuOH⁺, CuCO₃) was also less than 1% of the total Cu. Overlying water from the first flooding event was only acutely toxic to the Florida apple snail from one site. However, overlying water from the third flooding of six out of seven soils was acutely toxic to D. magna. The decrease in DOC concentrations and increase in bioavailable Cu²⁺ species may explain the changes in acute toxicity to D. magna. Results of this study reveal potential for high Cu bioavailability (Cu²⁺) and toxicity to aquatic biota overtime in inundated agricultural lands acquired under the CERP.

Impairment of water quality is a major concern for streams and rivers in the central USA. Total maximum daily loads (TMDLs) establish a watershed framework and set management targets to alleviate pollution from both point and nonpoint sources. For this study, we have used a hydrologic modeling approach to holistically examine the effect of land use management, urban development, and agricultural practices on sediment and nutrient loadings in an agricultural watershed. Annualized Agricultural Nonpoint Source (AnnAGNPS) simulation indicates that while point source dischargers contribute 8% of total nitrogen (TN) and 24% of total phosphorus (TP) loadings to the Marmaton River, agricultural nonpoint sources are the leading pollution source contributing 55% of TN and 49% of TP loading. Based on TMDL analysis and model simulation, 3% of the watershed area (3,244 ha) needs to be targeted to control TN loading whereas 1% of the total area (1,319 ha) is required for TP reduction management. Managing the TN areas alone can achieve a 57% reduction in the TP load required for the TMDL, whereas managing the targeted TP areas can only provide 30% of the required TN reduction. Areas required both TN and TP management comprise 469 ha. Targeting these areas can achieve approximately 22% of the required TN reduction and 29% of the required TP reduction. Overall, 4,094 ha will require management to achieve water quality goals. This study demonstrates that a modeling approach is needed to effectively address TMDL issues and help identify targeted areas for management.

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.

The effect of aluminium on histopathological and behavioral changes in the planarian Polycelis felina (Daly.) in laboratory conditions was studied. The planarians were treated with seven concentrations of aluminium sulfate for five days and compared to three control groups of animals. Microscopical, histological and morphometric methods were used. The results showed distinguished morphological changes on the planarian body as well as behavioral changes: various depigmentations, disordered locomotion, twisting of the body parts, hardly reacting to the mechanical stimuli, body contractions, deformations and mortality. Histomorphometric analyses showed changes in the size and number of neoblasts and reticular cells. Changes in epithelial cells and segments, parenchyma and muscular layer were also noticed. Concentrations of 600 and 1100 mg/L caused most distinct changes in behavior, morphological and histological structure of planarians. The highest concentrations caused irreversible changes. Considering high LC₅₀ (1100 mg/L), the used concentrations of aluminium presented no actual environmental threat to planarian populations in nature, but showed the extent of damages in a possible concentrated aluminium environment.

The work focuses on application of linear regression method for assessment of soil physicochemical parameters influence on ¹³⁷Cs accumulation. Besides organic matter content and pH, the parameters related to sorption properties of mineral parts and mobile ions concentration were considered. Before linear regression model is applied the data were transformed using Box-Cox formula. Selection of explanatory variables for regression was based on Akaike Information Criterion (AIC). Analysis of residuals distribution showed that linear regression can be applied for assessment of Cs⁺ accumulation in soil horizons. The important conclusion is that Cs⁺ cation migration in soil is usually influenced by more than a single horizon parameter. Common influence of two or more parameters on ¹³⁷Cs activity in soil horizon was observed. Our results suppose that migration of Cs in soil is affected mainly by horizon's acidity, presence of minerals and ion exchangeable substances. Some processes are probably affected by Cs⁺ individual properties, but other ones are not so selective.

Rhizobacteria possess a wide variety of qualities governing their pollutant-catabolic and rhizospheric competences. We investigated how the abilities to degrade phenanthrene and other polycyclic aromatic hydrocarbons (PAHs), to synthesize surfactants and the phytohormone indole-3-acetic acid (IAA), to be motile, and to perform chemotaxis toward phenanthrene and some potential root-exudate components were manifested in rhizobacteria isolated from oil-polluted sites. We observed that most of the examined rhizobacteria had the abilities under consideration and that in some strains, these were strongly affected by the bacterial environment. Only one strain--Sinorhizobium meliloti P221--exhibited increased PAH-degrading, surfactant-producing, and IAA-synthesizing activities, as well as distinct behavioral responses. We conclude that S. meliloti P221 can be used as a model to assess the contributions of all these activities to plant-inoculation-induced reduction in the soil PAH contents. This strain also may be useful for phytoremediation applications.

The chemical, mineralogical, and leaching behavior of three dominant Greek forest species ashes (Pinus halepensis, Pistacia lentiscus, and Olea europaea), before and after treating forest species with diammonium phosphate (DAP) 5% and 10% weight to weight, have been studied using a new five-step shake leaching method at pH = 6. For the analysis of ashes (prior and after leaching) and leachants, the following analytical techniques were used: atomic absorption spectroscopy, X-ray diffraction, and scanning electron microscopy with energy dispersive X-ray fluorescence analysis. The presence of DAP obstructs the extraction process of some metal ions (i.e., Na, K) contained in ashes by converting the soluble carbonate salts to the less soluble phosphates (i.e., Na₂CO₃ [rightward arrow] Na₃PO₄). On the contrary, DAP enhances the mobility of some other metals (i.e., Ca) by forming more soluble compounds [i.e., CaCO₃ [rightward arrow] Ca₃(PO₄)₂]. In addition, the presence of DAP lowers the pH of leachates, causing dissolution of some toxic elements (i.e., Mn, Pb, Zn). Unexpectedly, DAP prevents the leachability of Cr from ash. The above study concerns the environmental effects (soil and ground and underground water streams) caused by the use of chemical retardants on forest fires.

All commercial gasoline fuels build up deposits on the spark plugs, injectors, oxygen sensors, catalytic converter, and inside the combustion chamber, which will lower the engine's performance and increase air pollution. As a result, fuel-based detergents have been developed to prevent and remove unwanted deposits. Unfortunately, many of the detergents use high amounts of aromatic solvents, which result in a greater risk of exposure to aromatic compounds like benzene. In this study, car exhaust was analyzed for benzene, toluene, ethylbenzene, and xylenes (BTEX), as well as formaldehyde and acetaldehyde during engine cleaning service using different chemical cleaners. A special device was designed for sampling from car exhaust using solid phase microextraction. The extracted compounds were analyzed using a gas chromatograph with flame ionization detector. The cleaning products were rated with regard to the amount of pollutants produced during the cleaning service.

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.

A commercial strain of the fungus Pleurotus ostreatus was used to mediate the degradation of lindane, by landfarming technology during a 4 weeks statistical experiment. The Multilevel Factorial Design was used with two design factors, namely, straw content X ₁ (%) and lindane content X ₂ (ppm). The optimization parameters (responses) investigated were: biodegradation rate Y ₁ (μg d⁻¹), biomass growth rate Y ₂ (mg d⁻¹), biodegradation/biomass Y ₃ (μg mg⁻¹), total organic carbon Y ₄ (%), total organic nitrogen Y ₅ (%) and total organic carbon/total organic nitrogen Y ₆. The optima of the adequate models obtained for the period of 2 and 4-weeks were found. An overall kinetic study, conducted in this work with the aid of experimental design, determined the optimum (maximum) specific lindane degradation rate to be 0.16 g kg⁻¹ month⁻¹.