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.

Current-year, 1-year-old, and 2-year-old needles were collected separately on 37 black spruce (Picea mariana Mill. B.S.P.) trees located on a heavy metal contamination gradient around the smelter in Murdochville, Québec (Canada). Needles were analyzed separately by year for the concentrations of Pb and Cu, a nonessential and an essential metal, respectively. Lead concentrations increased significantly with needle age in the highly contaminated area near the smelter. In contrast, Cu concentrations decreased with needle age in the same area. Our results support the hypothesis that the passive sequestration of toxic metals in the senescing foliage is a detoxification process contrasting with the active translocation of essential metals in the nonsenescent part of the foliage.

This study determined the content of trace elements in coal ash collected from a coal-fired thermal power plant using local coal from Sawarak, Malaysia. This is crucial for the potential impact on the geoenvironment from its disposal and utilization; as coal ash has recently been produced locally in substantial amounts and very limited data is available. The trace elements concentrations presents in coal ashes are compared with the reported coal ash concentrations and the risk for the local wet tropical geoenvironment from the perspective of its vulnerability to these is studied for an indication of potential environmental implications on the wet tropics. The trace elements were found to be in concentrations that, if applied or inadvertently released into the environmental media, present a potential hazard and further necessary research in this regard is indicated.

The chemical characterization of contaminated soil was assessed in two study areas in Finland contaminated with metals. The aqua regia extractable and/or concentrated nitric acid leachable median concentrations of selected elements within the study areas were first compared to those from various geochemical baseline studies. Based on this comparison, the studied elements were divided into two groups: elements displaying general enrichment in the study areas and those with median concentrations within the range of baseline levels. In addition to comparison with the baseline levels, the distribution of aqua regia extractable concentrations of selected elements was assessed in relation to the Finnish soil screening values. The potential leachability of the selected metallic elements in contaminated, mainly man-made soil was examined by determining the ratio between the median ammonium acetate and median aqua regia extractable concentrations in the two study areas. Aqua regia extractable concentrations are considered to represent the near-total fraction of the elements and ammonium acetate extractable concentrations the 'bioavailable' fraction. These ratios were compared with those from non-polluted sites representing geochemical baselines. In addition, water soluble element concentrations were available from the two study areas and the ratio between synthetic rainwater or distilled, de-ionised water extractable and aqua regia extractable concentrations was calculated. The ratio between ammonium acetate extraction and aqua regia extraction indicated that of the studied elements, Cu, Ni, Pb, Zn and V exist in a more leachable form in contaminated soil than in the natural environment. It can be assumed that these elements are also more 'bioavailable' in contaminated land and could therefore pose a risk to the environment. The water soluble fraction of the potential harmful elements was generally low in both study areas, but single samples had easily leachable metal concentrations. High concentrations of trace elements were found in the groundwater on the down stream side of the potential pollution source. The chemical characteristics of the soil material in both study areas were defined with hierarchical cluster analysis, with the results presented as dendrograms produced using Ward's method. Although some clusters were identified from the dendrograms, no special characterization of the fill material was possible. However, suggestive grouping of certain element groups was observed. Similar grouping of elements was found in factor analysis. Cluster analysis as well as factor analysis was found to be feasible for the chemical characterization of soil provided that a sufficient number of samples with appropriate analysis are available.

Willows (Salix spp.) are an integral component in the restoration of wetland plant communities that have been impacted by the fluvial deposition of mine tailings. A greenhouse study was conducted to compare growth and metal uptake of Geyer (S. geyeriana) and mountain (S. monticola) willow grown in topsoil versus lime and biosolids amended mine tailings. Biomass, leader length, and tissue metal contents were measured after four months growth. Above and belowground biomass and leader length of Geyer willow were greater for plants grown in topsoil compared to amended mine tailings. However, soil type did not affect mountain willow growth. Analysis for five metals yielded complex results for the two willow species and soil types. As compared to mountain willow, Geyer had greater concentrations of Mn and Pb in aboveground tissues, and Cu in senesced leaves and bark-less leaders when grown in tailings; mountain willow leaves contained greater levels of Cd than Geyer when grown in tailings. Both willow species had foliar Cd levels which were above livestock toxicity tolerance values. Based on growth characteristics, mountain willow appeared better suited for restoration of mine tailings compared to Geyer willow. However, because of the high Cd uptake by both willow species, care should be taken in restoration efforts where wildlife and domestic livestock are likely to browse on the willows.

Recent studies have shown that natural perchlorate may be an important component to the general population exposure. These studies indicate that natural perchlorate is likely deposited by atmospheric deposition. Perchlorate concentration of total (dry + wet) deposition is relatively unstudied yet these measurements will aid in understanding natural levels in the environment. We sampled total deposition monthly at six sites in Suffolk County, Long Island, NY from November 30, 2005 until July 5, 2007. The mean perchlorate concentration is 0.21 ± 0.04 (standard error) μg L⁻¹ with a maximum value of 2.78 μg L⁻¹ . Here we show up to an 18-fold increase above the mean concentration in July 2006 and July 2007 samples. It appears that this increase in perchlorate in total deposition is associated with Fourth of July fireworks.

The effects of heavy metal contamination (Cr, Cu, Pb, Cd) in the lower basin of the Salado River (Argentina) were studied on the zooplanktonic community. The determination of heavy metals in water and sediments was carried out in a previous study. Zooplankton was analyzed quali- and quantitatively. Total density, by-group density (Copepoda, Cladocera and Rotifera), micro and mesozooplankton density, biomass, species richness (S), and species diversity (H) were studied. The results showed that total density of zooplankton was significantly higher in the river than in the channels and streams (p < 0.001), with dominance of rotifers but a higher copepod biomass. Calanoida dominated over Ciclopoidea and Harpacticoida. Total species richness was 74, showing the highest values (59 and 56) at the points corresponding to the Salado River at localities Manucho and San Justo (MSR, SJSR) and the lowest ones in North and South channels (NCH, SCH), with 16 and 17 species, respectively), and in the two sampling stations of Las Prusianas stream (LP1, LP2), between 13 and 38 species. The species diversity showed low values (1.8 to 2.3) in channels and streams, and higher values (3.0) in the Salado River, at Manucho and San Justo. Absolute biomass varied in the order SJSR > MSR > LP1 > NCH > SCH > LP2, similarly to absolute density, which varied in the order SJSR > MSR > LP1 > NCH > SCH > LP2. The comparison of the content of heavy metals in water between the control site (SJSR) and the most contaminated sites showed significant differences with the North and Las Prusianas 1 and 2 channels (ANOVA p = 0.001; 0.012 and 0.011, respectively) and non-significant differences, although close to the significance level, with the South Channel and Manucho (p = 0.08; p = 0.059). The following positive correlations were found: depth with mesozooplankton density, H and S (p < 0.001); temperature with microzooplankton density, H and S (p < 0.004), and dissolved oxygen with mesozooplankton density, H and S (p < 0.01), but not with microzooplankton, indicating a higher tolerance of the organisms belonging to this fraction. A negative correlation was found between biomass of copepods and concentration of Pb and Cu (p < 0.05 and p = 0.01, respectively). Rotifers were the most tolerant to heavy metal contamination, followed by copepods and cladocerans. Diversity (H) and richness (S) were good indicators of stress of contaminated systems. The clustering of biological variables and the concentration of heavy metals in water and sediments showed three groups of environments: the first one was the main course of the river, with lower contamination by heavy metals and higher density, biomass, H and S, which separated clearly from the other two groups of the tributaries, composed by channels and streams. In the tributaries, r strategists and a few tolerant species, such as Eucyclops neumani, proliferated. The results of this study show that zooplankton responds as good descriptor of water quality, constituting an efficient tool to assess heavy metal contamination.

Leaching of trace metals and greenhouse plant growth (Collard greens; Brassica oleracea var. acephala) response studies were conducted in two types of soils with contrasting characteristics amended with varying rates (0 to 24.70 Mg ha⁻¹) of poultry litter (PL) or 1:1 mixture of PL and fly ash (FA). Leaching of Cr, Zn, Cd, Cu, and Pb from soils amended with PL or PL + FA (1:1) increased with increasing rates of amendment. Leaching losses were greater from coarse-textured soil compared to that from medium-textured soil. Crop performance study indicated that growth as well as trace elements concentrations increased with increasing rates of amendments only up to 12.35 Mg ha⁻¹. Trace element concentrations in plant parts were greater in plants grown in Candler fine sand (CFS) compared to that grown in Ogeechee loamy sand (OLS). Trace element concentrations were greater in the above ground plant parts (leaf and stem) than those in roots. This study demonstrated beneficial effects of PL or mixture of PL + FA amendments to soils at rates not exceeding 4.94 Mg ha⁻¹. Further field studies are recommended to evaluate the long-term impact of using poultry litter and fly ash on plant growth and tissue trace metal concentration as well as environmental impact.

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.