Buffer capacity analysis of open atmospheric gas-liquid systems containing main acidic and basic atmospheric pollutants was carried out. Usually the buffer capacity is considered as a function of pH as an independent variable. In this work the buffer capacity is analysed including the dependence of pH on the composition of a system. Such an approach allows finding an important, from the viewpoint of atmospheric water acidification, relationship between the gas phase composition and the buffer capacity. It was found that buffer capacity of the open gas-liquid systems may be very high and it may cause the liquid phase pH to remain at low levels. The buffer capacity of the analysed systems is most strongly affected by the simultaneous presence of ammonia and strong acids in the gas phase. The higher concentrations of strong acid gases the lower NH₃ concentration is sufficient to achieve high buffer capacity. In the presence of strong acid gases, calcium ions affect both the buffer capacity and the liquid phase pH only at low NH₃ concentrations. High buffer capacity of open gas-liquid systems may be one of the reasons why the reduction in emissions of acidic gas pollutants has little effect on decrease in atmospheric water acidity.

The biodegradation kinetics of anionic (sodium laureth sulfate - SLES), amphoteric (disodium cocoamphodiacetate - DSCADA), and nonionic surfactants (polyalcohol ethoxylate - PAE) were assessed in this laboratory study. Similar degradation behavior was observed for all surfactants with only a fraction of the parent compound readily biodegradable. Biodegradation, as estimated by COD removal, was initially (i.e., within 24 h) rapid, however only 40-70% of the surfactant molecules were readily biodegradable. Intrinsic kinetic parameters were successfully quantified for the readily biodegradable component of the surfactant. Inhibition was not observed and microbial kinetics of SLES, DSCADA, and PAE degradation fit the Monod model well. Average μ-S curves were generated for each surfactant. Based on these results, complete degradation of the target surfactants using biological waste treatment would be limited.

The objectives of this study are: (1) Evaluate the capacity of Indian mustard (Brassica juncea) for uptake and accumulation of Cs and Sr natural isotopes. (2) Identify foliar structural and other physiological changes (biomass, relative water content etc.) resulted from the accumulation of these two elements. (3) Monitor the Cs and Sr uptake and bioaccumulation process by spectral reflectance. Potted Indian mustard plants were exposed to different concentrations of Cs (50 and 600 ppm) and Sr (50 and 300 ppm) natural isotopes in solution form for 23 days. Bioaccumulation of Cs and Sr were found in the order of leaves > stems > roots for both Cs- and Sr-treated plants. The highest leaf and root Sr accumulations are observed to be 2,708, and 1,194 mg kg⁻¹, respectively; and the highest leaf and root Cs accumulations are 12,251, and 6,794 mg kg⁻¹, respectively. High translocation efficiency for both elements is documented by shoot/root concentration ratios greater than one. Biomass decreases were observed for plants treated with higher concentration of Cs or Sr. Cs accumulation affected the pigment concentration and internal structure of the leaf and the spectral characteristics of plants. Within the applied concentration range, Sr accumulation resulted in no significant changes in relative water content (RWC), leaf structural and spectral characteristics of mustard plants. Cs shoot concentration showed significant negative correlation with relative water content (RWC; r = −0.88*) and normalized difference vegetative index (NDVI) value (r = −0.68*) of plant shoots. The canopy spectral reflectance and NDVI analysis clearly revealed (p < 0.05) the stress caused by Cs accumulation.

The SO₄-S and NO₃-N concentrations and pH in bulk precipitation, throughfall, stemflow and soil water for the 1994-2004 period were studied in pine forests in Latvia (Rucava and Taurene Integrated Monitoring stations). The SO₄-S and NO₃-N concentrations decreased over the study period, simultaneously with a decrease of acidity in precipitation. The changes were more evident in the western part of Latvia, probably due to declining long-range air pollution from West Europe. The trend of decreasing sulphate concentrations and increasing pH in precipitation were not followed by respective changes in soil water. In the upper soil horizon sulphate ion concentrations and acidity increased in soil water. Over the observation period, nitrate concentrations also showed an increasing trend in soil water at Rucava and Taurene, but these changes were not statistically significant.

Douglas fir [Pseudotsuga menziesii (Mirb.) Franco] shoots from mature trees were collected from two sites of contrasting soil pH: the Glendon campus of York University in Toronto, Canada (pH 6.7 at 40 cm) designated Can.; and Breuil Forest, Morvan, France (pH 4 to 4.5) designated Fr.. Needles were removed from the shoots, frozen in liquid nitrogen, and kept in a cryo-biological storage system prior to X-ray microanalysis on the cold stage (-170°C) of a cryo-SEM. Four elements detected, potassium, phosphorus, sulphur and chlorine, were ubiquitous in the needle tissues from both sites. Manganese was infrequently found in needle tissues from the Fr. site. Calcium was localized most heavily in the outer tangential wall of the hypodermis and also in the epidermal walls. Silicon (Si) concentrations were higher in the Fr. site than in the Can. site. The epidermis, hypodermis and mesophyll of needles from the Fr. site exhibited the highest Si content, with greater amounts in the tip and middle of the needle than in the base. Aluminium was distributed fairly evenly throughout the tissues, and there were few major sites of concentration.

The use of vegetated wetlands for accelerating pesticide removal from agricultural runoff is gaining acceptance as a best management practice. In this study, the dissipation of five cotton pesticides – endosulfan, chlorpyrifos, aldicarb, prometryn and diuron – was quantified in cotton field runoff water contained in glasshouse columns, under light or dark conditions. Two water samples sourced from large, non-vegetated storage dams were compared with two other water samples obtained from vegetated wetlands receiving runoff from cotton fields. All pesticides studied except chlorpyrifos dissipated significantly faster from the storage dam samples than the vegetated wetland samples. Suggested reasons include a greater number of pesticide-degrading microorganisms in the storage dam waters and/or the presence of more organic matter in the wetland samples, limiting contaminant volatilisation and hydrolysis. Exposure to light significantly reduced the rate of endosulfan removal, whereas light increased the rate of chlorpyrifos removal. Half-lives are presented for each pesticide where appropriate.

The main factors determining the geochemical fate of copper in urban freshwaters affected by raw sewage discharges were investigated in this work. Water samples from the Iraí and Iguaçu rivers were collected monthly during a 1-year period at two points located upstream and downstream from the city of Curitiba, in Brazil. Results revealed that raw sewage discharges from the heavily urbanized area caused an enhancement of humic-coated suspended solids in the Iguaçu River. In these waters copper is predominantly associated with the humic-coated particles whereas in the Iraí River copper was found primarily in the aqueous phase. The transfer of copper from the aqueous to the solid phase changed its physical speciation along the watercourse. Thus, aspects related to the overall transport of trace metals in watercourses become an important issue to be considered in further studies concerning the effect of sewage discharges on the geochemical speciation and fate of trace metals in urban rivers.

Mercuric ions (Hg²⁺) and methylmercury are major, human-generated, toxic contaminants present in fish and our waterways. Bacteria provide a means of bioremediation by taking up these compounds and reducing them to volatile, non-toxic, elemental mercury (Hg°). Three types of mercury/methylmercury transporters have previously been identified: MerC, MerF and MerT. Each of these sets of homologues has distinct topologies. MerF proteins are characterized by a 2-transmembrane α-helical segment (TMS) topology; most MerTs have three TMSs, and MerCs have four TMSs. This report shows that MerT and MerF proteins are related by common descent and are similar in sequence throughout their first two TMSs. One of the MerF proteins is internally duplicated, generating a protein with four TMSs, while several MerT homologues bear a C-terminal extracytoplasmic Hg²⁺-binding MerP domain. MerPs are homologous to heavy metal-binding domains present in copper chaperone proteins, at the N-termini of mercuric reductases and in from one to six copies in heavy metal transporting P-type ATPases. Phylogenetic analyses reveal that mercuric ion transporters have been horizontally transferred with high frequency between bacteria. Some MerTs function with MerP receptors while others do not, and the MerP-dependent MerTs cluster separately from the MerP-independent MerTs on a phylogenetic tree. MerTs possessing a MerP appear to have co-evolved with their cognate receptors. Conserved sequence and motif analyses serve to define the mercuric transporter family fingerprints and allow prediction of specific subfunctions. This report provides the first detailed bioinformatic description of two apparently unrelated families of Hg²⁺ uptake transporters. We propose that all members of these two families function by a simple channel-type mechanism to allow influx of Hg²⁺ in response to the membrane potential in preparation for reduction and detoxification. This information should facilitate the exploitation of these transporters for purposes of microbial and phytobioremediation.

The importance of the chemical composition in evaluating groundwater flow is discussed. Two different geological environments, a felsic volcanic region around San Luis Potosí (SLPB), Mexico, and a sedimentary basin, part of the Pannonian Basin (PB), in Hungary, were chosen to explore the effect of local, intermediate and regional groundwater flows on the chemical evolution of water in different geological circumstances. In the study areas contrasting stable isotopes and groundwater temperature values, as well as the chemical composition of groundwater were convenient tools to propose groundwater flow direction and to study contamination processes in the different groundwater flow systems. Results indicate that regardless of the geological framework variability of the chemical composition of the shallow (<100 m) groundwater is significant; at depth the chemical content of groundwater becomes homogeneous, and the concentrations are smaller than at shallow depths. The Cl- and NO- ₃ concentrations indicate mainly up- and downward vertical flow directions suggesting local flow systems in the shallow layers. The linear regression between Cl- and Na⁺ suggests that evaporation processes are the main control of the Cl- concentration. Deviations from the regression line suggest processes such as pollution at shallow depths in both study areas. Based on the distribution of Ca⁺², Mg⁺² and Na⁺, a lateral flow can be traced. The large dimensions of the geological units involved with the regional flow systems implies a long groundwater flow path, also these flows remain isolated from anthropogenic contamination, then groundwater has not been altered by human influence, although in the SLPB a communication between the local and intermediate flows has been found. Recharge areas of the local and intermediate flow systems are more vulnerable to contamination processes than the discharge areas, where the expected low dissolved oxygen content of ascending water could play a control. Differences in the lithology between the PB (sedimentary basin) and the SLPB (felsic volcanic basin) explain the contrasting saturation indices calculated for chalcedony and calcite and the lack of the expected development of HCO- ₃, SO-² ₄ Cl- facies and contrasting aerobic/oxidizing conditions.

The roles of ectomycorrhizal fungi and bacteria associated with corresponding fungal species in distribution of heavy metals within roots and shoots of inoculated pine (Pinus sylvestris L.) seedlings were determined in this study. The mycorrhizal fungi forming different morphotypes were identified by PCR-RFLP using respective primers for an internal spacer transcribed region (ITS) of fungal rDNA. Amongst five fungal species detected, three were identified as Scleroderma citrinum, Amanita muscaria and Lactarius rufus. These fungi used for inoculation of pine seedlings significantly reduced translocation of Zn(II), Cd(II) or Pb(II) from roots to shoots, and the pattern of metal-accumulation was dependent on the fungal species. Ectomycorrhizae-associated bacteria identified as Pseudomonas were used as an additional component of the pine inoculation. These dual root inoculations resulted in higher accumulation of the metals, especially Zn(II), in the roots compared to the inoculation with fungal species alone. Consequently, dual inoculation of pine seedlings could be a suitable approach for plant protection against heavy metals and successful planting of metal-polluted soils.