The Loxahatchee National Wildlife Refuge (Refuge) developed as a system with waters low in nutrients. Today, the Refuge wetlands are impacted by inflows containing elevated nutrient concentrations originating from agricultural sources flowing into canals surrounding the west side and from urban and horticultural areas flowing into canals surrounding the eastern side of the Refuge. We analyzed water quality sampled at 40 sites divided into eastern and western areas and four zones in the Refuge. We defined four zones as the canals surrounding the Refuge marsh, the perimeter zone, the transition zone, and the interior zone. The canal receiving agricultural inflows had greater alkalinity and conductivity (SpC), Si and SO4 but lower turbidity and total suspended solids than the canal receiving urban and horticultural inflows. Alkalinity, total dissolved solids (TDS), SpC, Ca, Cl, and SO4 concentrations were greater in the perimeter than in transition and interior zones. Alkalinity and SpC values and SO4 concentrations were greater in the transition than in interior zone. Alkalinity, SpC, and TDS values and Ca, SO4, and Cl concentrations correlated in negative curvilinear relationships with distance from the canal (r 2 = 0.78, 0.70, 0.61, 0.78, 0.64, 0.57, respectively). Analysis of multiple water quality parameters may reveal the complexity of interactions that might be overlooked in a simple single parameter analysis. These data show an impact of canal water containing high nutrient concentrations on water quality flowing from the canal towards the Refuge interior.

To elucidate the influence of airborne materials on the ecosystem of Japan’s Yakushima Island, we determined the elemental compositions and Sr and Nd isotope ratios in streamwater, soils, vegetation, and rocks. Streamwater had high Na and Cl contents, low Ca and HCO₃ contents, and Na/Cl and Mg/Cl ratios close to those of seawater, but it had low pH (5.4 to 7.1), a higher Ca/Cl ratio than seawater, and distinct ⁸⁷Sr/⁸⁶Sr ratios that depended on the bedrock type. The proportions of rain-derived cations in streamwater, estimated by assuming that Cl was derived from sea salt aerosols, averaged 81 % for Na, 83 % for Mg, 36 % for K, 32 % for Ca, and 33 % for Sr. The Sr value was comparable to the 28 % estimated by comparing Sr isotope ratios between rain and granite bedrock. The soils are depleted in Ca, Na, P, and Sr compared with the parent materials. At Yotsuse in the northwestern side, plants and the soil pool have ⁸⁷Sr/⁸⁶Sr ratios similar to that of rainwater with a high sea salt component. In contrast, the Sr and Nd isotope ratios of soil minerals in the A and B horizons approach those of silicate minerals in northern China’s loess soils. The soil Ca and P depletion results largely from chemical weathering of plagioclase and of small amounts of apatite and calcite in granitic rocks. This suggests that Yakushima’s ecosystem is affected by large amounts of acidic precipitation with a high sea salt component, which leaches Ca and its proxy (Sr) from bedrock into streams, and by Asian dust-derived apatite, which is an important source of P in base cation-depleted soils.

Groundwater drains used to manage saline watertables in the semi-arid zone of south-western Australia can discharge acidic saline water with high concentrations of metals to waterways. Mitigating the acidity impacts of the waters requires sulfate-reducing bioreactors capable of functioning under semi-arid conditions with limited source materials. Two simple pilot-scale bioreactor designs using straw and sheep manure mixtures were evaluated over several years. The bioreactors increased pH from <3.5 to >5.5 for 125–260 days, with concurrent evidence of sulfate reduction, >85% reductions in net acidity and >90% reductions in Al and most trace elements (e.g. Pb, Cu, Ni, Zn, Ce and La). When outflow pH < 5.5 (remaining greater than inflows), reduction in net acidity was 10–80% but concentrations of Pb, Cu and Ni remained >80% reduced over periods of 250 to >700 days. Rates of alkalinity generation initially exceeded 10 g CaCO3/m2/day in both bioreactors thereafter decreasing to >1–2 CaCO3/m2/day. Al and Fe retention was implicated in trace metal removal when pH < 5.5, mediated by biological alkalinity generation. High evaporation rates limited bioreactor function by restricting outflows with no benefits to alkalinity generation rates. This experiment showed that simple bioreactors can neutralise acidic waters and remove metals for short durations and show capacity for sustained reduction in acidity and metal concentrations over several years despite low alkalinity generation.

The aim of the study was to determine whether the application of superphosphate fertiliser to soils contaminated with mine wastes can inhibit metal and metalloid mobility (Cu, Pb, Zn, Cd, Fe, Mn, As, Sb) in the long term. Contaminated soils contained sulfide- and sulfate-rich waste materials from the Broken Hill and Mt Isa mining centres. Results of long-term (10 months) column experiments demonstrate that fertiliser amendment had highly variable effects on the degree of metal and metalloid mobilisation and capture. Rapid release of metals from a sulfate-rich soil showed that phosphate amendment was ineffective in stabilising highly soluble metal-bearing phases. In a sulfide-rich soil with abundant organic matter, complexing of metals with soluble organic acids led to pronounced metal (mainly Cd, Cu and Zn) release from fertiliser-amended soils. The abundance of pyrite, as well as the addition of fertiliser, caused persistent acid production over time, which prevented the formation of insoluble metal phosphate phases and instead fostered an increased mobility of both metals and metalloids (As, Cd, Cu, Sb, Zn). By contrast, fertiliser application to a sulfide-rich soil with low organic carbon content and a sufficient acid buffering capacity to maintain near-neutral pH resulted in the immobilisation of Pb in the form of newly precipitated Pb phosphate phases. Thus, phosphate stabilisation was ineffective in suppressing metal and metalloid mobility from soils that were rich in organic matter, contained abundant pyrite and had a low acid buffering capacity. Phosphate stabilisation appears to be more effective for the in situ treatment of sulfide-rich soils that are distinctly enriched in Pb and contain insignificant concentrations of organic matter and other metals and metalloids.

Coagulation and flocculation are basic chemical engineering operations employed to remove suspended solids from water. The growing concern for environmental and ecological issues warrants the use of the biodegradable flocculants in wastewater and industrial effluent treatment. In this work, unconventional coagulant, namely lactic acid, calcium lactate, sodium lactate, and citric acid were studied in comparison with AlCl3, a usual coagulant widely employed to remove water turbidity. It was observed that lactic acid and calcium lactate were able to reduce the water turbidity similarly to AlCl3. This fact can be very interesting because lactic acid salts can be produced by biotechnological process, and contrarily to aluminium salts, they are biodegradable, reducing the risk for human and animal’s health.

Phosphorus (P) releases to the environment have been implicated in the eutrophication of important water bodies worldwide. Current technology for the removal of P from wastewaters consists of treatment with aluminum (Al) or iron (Fe) salts, but is expensive. The neutralization of acid mine drainage (AMD) generates sludge rich in Fe and Al oxides that has hitherto been considered a waste product, but these sludges could serve as an economical adsorption media for the removal of P from wastewaters. Therefore, we have evaluated an AMD-derived media as a sorbent for P in fixed bed sorption systems. The homogenous surface diffusion model (HSDM) was used to analyze fixed bed test data and to determine the value of related sorption parameters. The surface diffusion modulus Ed was found to be a useful predictor of sorption kinetics. Values of Ed < 0.2 were associated with early breakthrough of P, while more desirable S-shaped breakthrough curves resulted when 0.2 < Ed < 0.5. Computer simulations of the fixed bed process with the HSDM confirmed that if Ed was known, the shape of the breakthrough curve could be calculated. The surface diffusion coefficient D ₛ was a critical factor in the calculation of Ed and could be estimated based on the sorption test conditions such as media characteristics, and influent flow rate and concentration. Optimal test results were obtained with a relatively small media particle size (average particle radius 0.028 cm) and resulted in 96 % removal of P from the influent over 46 days of continuous operation. These results indicate that fixed bed sorption of P would be a feasible option for the utilization of AMD residues, thus helping to decrease AMD treatment costs while at the same time ameliorating the impacts of P contamination.

The characteristics (natural, socioeconomic and administrative/institutional) of Alfeios River basin, in Greece, are identified and presented, incorporating and critically reviewing all possibly found literature. The Alfeios River is a water resources system of great natural, ecological, social and economic importance for Western Greece, since it has the longest and highest flow rate watercourse in the Peloponnisos region. Moreover, the river basin was exposed in the last decades to a plethora of environmental stresses (such as hydrogeological alterations, intensively irrigated agriculture, surface and groundwater overexploitation and infrastructure developments), resulting in the degradation of its quantitative and qualitative characteristics. It is therefore necessary for the development of an integrated river basin management plan for this basin, to study and analyse the interplay between the river components and the exerted environmental stresses, taking into account the puzzle of various and conflicting water uses, including water supply, irrigation, hydropower generation, lignite thermal power production and recreation. Mitigative, preventive and control measures for the analysed environmental stresses are epigrammatically depicted. Focusing on the problematic features, the present work provides a concrete foundation for the determination and conceptualisation of management objectives and possible sustainable alternatives.

In order to assess the use of magnetic methods to study vertical migration behavior of metal pollutants in natural soils, a controlled experiment was performed near Belle River, Ontario, Canada. The soil at the site consists primarily of clay-rich glacial till overlain by localized alluvium. Twenty PVC tubes (16″ × 8″) were inserted vertically into the ground as test capsules. Magnetite powder (<5 μm) was distributed on the surface of the soil inside ten tubes (10 grams/tube) to simulate anthropogenic contamination, while the other ten were used as controls. While the surficial magnetic susceptibility (MS) remained fairly stable in controls, decreases of 15–60% were observed in contaminated soil tubes. Post-test MS profiles from soil cores in contaminated tubes show that the magnetic signal is strongest at depths between 4 and 6 cm. Magnetic measurements and chemical analysis (using SEM-EDS) on soil layers with enhanced magnetic signal indicate the presence of iron containing particles, likely magnetite. Overall, the results suggest that magnetite powder migrated vertically downwards at a rate of ∼14 cm/year over the four month period, probably as a result of rainwater infiltration. Such magnetic methods and chemical analytical techniques are useful in the investigation of migration of metal pollutants and the potential depth of soil contamination.

The adsorption behavior of denim blue from aqueous solutions in column systems, using both carbonaceous material and Fe-zeolitic tuff (Fe-Z), was determined. The breakthrough data obtained for denim blue adsorption were fitted to the empty-bed contact time, Bohart–Adams, Thomas, and Yoon–Nelson models. The parameters such as breakthrough and saturation times, bed volumes, kinetic constants, adsorption capacities, and adsorbent usage rates (AUR) were determined. The results show that the breakthrough time increases proportionally with increasing bed height, but it decreases as the kinetic constant increases. The adsorption capacity for denim blue for carbonaceous material was higher than Fe-Z. AUR was lower for carbonaceous material than Fe-Z. The results indicated that the carbonaceous material from pyrolysis of sewage sludge is a good adsorbent for denim blue removal.

Using an automated gas chromatography system coupled with an online sampling/thermal desorption module, benzene, toluene, and their alkylated derivatives were measured in Las Vegas, Nevada from 3 July to 28 August 2008. The levels of hydrocarbons were comparable to those typically found in urban environments. Statistically significant (at 95 % level) higher concentrations were measured on mid-week days as compared with those measured during weekends. This was correlated to a local traffic pattern rather than traffic on highways. The concentrations of aromatic hydrocarbons also increased during periods when transport of smoke from wildfires in central and north California was identified by remote sensing but these levels were comparable to other days with volatile organic compounds concentrations. The high toluene/benzene ratios and the estimated photochemical age of air masses implied the contribution of other local sources. Fuel evaporation accounted for the vast majority of toluene enhanced concentrations in early July (as compared with those measured in June) for sites within the urban grid, but very little for sites located outside the urban area.