Mercury (Hg) stored in vegetation and soils is known to be released to the atmosphere during wildfires, increasing atmospheric stores and altering terrestrial budgets. Increased erosion and transport of sediments is well-documented in burned watersheds, both immediately post-fire and as the watershed recovers; however, understanding post-fire mobilization of soil Hg within burned watersheds remains elusive. The goal of the current study is to better understand the impact of wildfire on soil-bound Hg during the immediate post-fire period as well as during recovery, in order to assess the potential for sediment-driven transport to and within surface waters in burned watersheds. Soils were collected from three southern California watersheds of similar vegetation and soil characteristics that experienced wildfire. Sampling in one of these watersheds was extended for several seasons (1.5 years) in order to investigate temporal changes in soil Hg concentrations. Laboratory analysis included bulk soil total Hg concentrations and total organic carbon of burned and unburned samples. Soils were also fractionated into a subset of grain sizes with analysis of Hg on each fraction. Low Hg concentrations were observed in surface soils immediately post-fire. Accumulation of Hg coincident with moderate vegetative recovery was observed in the burned surface soils 1 year following the fire, and mobilization was also noted during the second winter (rainy) season. Hg concentrations were highest in the fine-grained fraction of unburned soils; however, in the burned soils, the distribution of soil-bound Hg was less influenced by grain size. The accelerated accumulation of Hg observed in the burned soils, along with the elevated risk of erosion, could result in increased delivery of organic- or particulate-bound Hg to surface waters in post-fire systems.

Side effects related to liming have been studied in four dimictic lakes (553-642 m a.s.l.; 59°57′N) in Finnemarka, a forested area in Southern Norway with poor catchment buffer capacity. Data series from lake profiles have been sampled two decades apart; 10 years prior to liming and after 10 years of liming. Water samples were collected during spring after ice breakup and during summer after the development of thermal stratification. Before liming, there were very low concentrations of bicarbonate (HCO ₃ ⁻ ; or alkalinity) in the lakes. After 10 years of liming, up to 90% of the ions in hypolimnion originate from lime products. Hence, liming strengthened the chemical stratification and increased the vertical stability. Differences in chemocline developments between lakes were explained by differences in physical properties, i.e. their depth/surface area ratio. The chemocline developments lead to increased concentrations of organic matter in the hypolimnion with a subsequent reduction in oxygen concentrations. Lime additions during late spring, as an alternative to early autumn, lead to pronounced anoxic conditions in the hypolimnion.

Atmospheric and sea sediment concentrations were measured for eight nitrated polycyclic aromatic hydrocarbons (nitro-PAHs) and three unsubstituted PAHs in a suburban area and sea sediments in the Hiroshima Bay watershed area, Japan, from July to December, 2006 (atmospheric particulate matter) and in September and November, 2004 (sea sediments). Atmospheric concentration was higher in winter than summer for both nitro-PAHs and PAHs. Concentrations in sea sediments were less than 10%, and pattern was similar to those of atmospheric particles. Several combustion emission sources were also measured, and the 1-NP/Pyr ratio was compared to environmental values. The ratio of atmospheric and sea sediments were significantly lower than diesel particulate matters. Further, the vehicle emission loading and sea sedimentation loading was evaluated in this watershed area, and from the comparison, the existence of other important sources PAHs were suggested.

Reductive dechlorination of tetrachloroethylene (PCE) by green rust modified with copper (GR(Cu)) was investigated using a batch reactor system. Four different forms of GRs (GR-Cl, GR-SO₄, GR-CO₃, and GR-F) were synthesized by partial air oxidation of Fe(OH)₂ and used in reductive dechlorination. The addition of Cu(II) into GRs produced 100-nm particles on the surface of GRs, which were considered to be metallic Cu and transformed a portion of GR to magnetite. Concentration of Fe(II) in the liquid phase increased and concentration of Fe(II) in the solid phase decreased during the modification process and the extent of these changes was dependent on the amount of Cu(II) added. The most reactive of the modified GRs was GR-F(Cu), which reacted with PCE at a rate that was 80 times faster than that of GR-Cl(Cu). The rate of PCE degradation by GR-F(Cu) was strongly dependent on pH with higher rates at higher pH over the range of pH 7.5-11. Increasing concentrations of Cu(II) over the range of 0 to 5 mM increased rate constants. The rate of dechlorination of PCE by GR-F(Cu) showed surface saturation behavior with respect to PCE concentration.

Investigations were made on living strains of fungi in a bioremediation process of three metal (lead) contaminated soils. Three saprotrophic fungi (Aspergillus niger, Penicillium bilaiae, and a Penicillium sp.) were exposed to poor and rich nutrient conditions (no carbon availability or 0.11 M d-glucose, respectively) and metal stress (25 µM lead or contaminated soils) for 5 days. Exudation of low molecular weight organic acids was investigated as a response to the metal and nutrient conditions. Main organic acids identified were oxalic acid (A. niger) and citric acid (P. bilaiae). Exudation rates of oxalate decreased in response to lead exposure, while exudation rates of citrate were less affected. Total production under poor nutrient conditions was low, except for A. niger, for which no significant difference was found between the poor and rich control. Maximum exudation rates were 20 µmol oxalic acid g⁻¹ biomass h⁻¹ (A. niger) and 20 µmol citric acid g⁻¹ biomass h⁻¹ (P. bilaiae), in the presence of the contaminated soil, but only 5 µmol organic acids g⁻¹ biomass h⁻¹, in total, for the Penicillium sp. There was a significant mobilization of metals from the soils in the carbon rich treatments and maximum release of Pb was 12% from the soils after 5 days. This was not sufficient to bring down the remaining concentration to the target level 300 mg kg⁻¹ from initial levels of 3,800, 1,600, and 370 mg kg⁻¹in the three soils. Target levels for Ni, Zn, and Cu, were 120, 500, and 200 mg kg⁻¹, respectively, and were prior to the bioremediation already below these concentrations (except for Cu Soil 1). However, maximum release of Ni, Zn, and Cu was 28%, 35%, and 90%, respectively. The release of metals was related to the production of chelating acids, but also to the pH-decrease. This illustrates the potential to use fungi exudates in bioremediation of contaminated soil. Nonetheless, the extent of the generation of organic acids is depending on several processes and mechanisms that need to be further investigated.

The amounts of nitrogen and sulfur deposited in the region of the Yellow Sea in both dry and wet forms were estimated focusing on the period between 1999 and 2000. Dry deposition fluxes were obtained using concentrations from ground stations on both Korean and Chinese sides and from shipboard and aircraft measurements. Wet deposition fluxes were determined at ground stations on the Korean side. The dry deposition flux over the Yellow Sea was much greater than those for other world oceans. As a whole, the amounts of wet depositions of nitrogen and sulfur were 1.9 and 1.5 times larger than the amounts of respective dry depositions. Substantial influence from China caused by high emissions in East China and westerly wind was possibly suggested. However, the influence from nitrogen emission in Korea was also confirmed.

Lake Vela (Littoral Centre of Portugal) is considered a natural habitat with community interest and consequently was included in the Natura 2000 Network. However, this freshwater ecosystem has been potentially exposed to diffuse pollution generated by agricultural and livestock activities, which seriously compromise its ecological balance. As part of the Ecological Risk Assessment (ERA) proposed for Lake Vela, this study aimed to evaluate the occurrence of pesticides in different compartments: surface water, groundwater, sediments, and fish tissues. Moreover, to assess potential concerning effects on ecosystem and human health, the measured concentrations of pesticides were compared with regulatory and toxicological benchmarks. The results confirmed the presence of high concentrations of pesticides, including organochloride pesticides banned decades ago, in surface water, groundwater, and sediment. The measured concentrations of pesticides, compared with toxicological benchmarks, indicated that harmful effects are likely for aquatic species due to the presence of alachlor, aldrin, and dieldrin. Additionally, the concentrations of pesticides detected in groundwater were also above the recommended safety levels for drinking water, which constitutes a concern for the local population's health. Results also showed an accumulation of alachlor in predator and benthic fish species which could represent a risk to human consumers and particularly to the regular fish predators (e.g., otters and birds). This study, as the first exposure characterization performed on the Lake Vela system, constitutes valuable and useful information for the ERA process. Although this preliminary assessment of risks should be continued and confirmed through a weight-of-evidence approach, it had already unraveled how concerning are the problems in this ecosystem and the urgency of implementing restoration measures to guaranty its sustainability. Furthermore, this study reinforces the importance of evaluating similar freshwater ecosystems that are also highly threatened by diffuse pollution.

Phosphorus (P) loss from agricultural soils to water is a major contributor to eutrophication. In an incubation experiment with five contrasting soils, lime and gypsum showed potential as source measures to decrease P loss risk, as assessed by water extractions. Soils were incubated with lime to achieve a target pH of 6.5 and with gypsum at equivalent Ca rates for 108 days. P was added (17 kg P ha⁻¹) as KH₂PO₄ in solution. Gypsum appears to have greater potential as a source measure, decreasing molybdate-reactive P (RP) solubility by 14-56% and organic P (OP) by 10-53% across all soils. RP and Ca may have precipitated or co-sorbed, and OP may have been stabilised in organic matter complexes due to the bridging effect of Ca and the flocculating effect of increased ionic strength. Greater effectiveness of gypsum may be due to its higher solubility and the fact that it increases Ca concentrations without increasing pH. Lime decreased RP solubility in two soils (by 4% and 20%) but increased solubility in two and had no effect in a third. The overall effect of lime may depend on several competing effects of raised pH and Ca concentration that may vary in importance depending on soil characteristics such as base cation and P status. For the highest P status soil, both lime and gypsum were effective, decreasing RP solubility by 4% and 15%, respectively. Targeted treatment of high P soils may be an effective and economical strategy to minimise P losses.

The present study determines the source of dust particles and investigates their impact on the chemical compositions of plants and soils around a cement factory in Oman within a radius of 10 km of this disturbed ecosystem. A total number of nine samples of the species of plants (Rhazya stricta), nine samples of soils, and nine samples of dust were collected and analyzed for major ions and trace elements including rare earth elements (REEs). Principal component analysis applied to the major and trace element concentrations in the dust indicated the input of at least two sources to the dust in the study area: ophiolites and cement. The REE distribution in the plants and soils revealed that the most available elements to plants originated dominantly from ophiolites rather than from cement. The contribution of cement industry is significant only in the zone located at about 0.500 to 2 km around the cement factory, whereas the contribution of ophiolites increases with distance from the cement factory.

The main objective of this study was to examine the efficacy and capacity of constructed wetlands for metal removal. Between January 2006 and December 2008, removal of Cr, Cu, Cd, Zn, Pb, B, Ni, As, Fe, Hg, and Mn was measured on a monthly basis at a hierarchical mosaic of artificial ecosystems which has been in operation since 1998. The results showed a great variety of average removal efficiencies, in the range of 55% for chromium and −73% for manganese. Four elements presented negative removal: nickel, iron, arsenic, and manganese. Seasonal removal efficiencies were also studied for each element. Moreover, a correlation assessment among metal removal efficiencies and different parameters of each basin in the hierarchical mosaic of artificial ecosystems was performed. Negative significant correlations were found among Fe, Zn, Cu, Mn, As, Ni, Cd, and Hg removal and the inlet concentrations. In general, the treatment system was not a good system for removal of metals from wastewater as, in relation to other constructed wetlands, the system was not able to provide efficient removal of metals.