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.

A simple and very sensitive method determining microgram quantities of indium in soil has been developed. The spectrophotometric method (ε = 1.74 x 10⁵ l mol⁻¹ cm⁻¹) based on the mixed complex In (III) with Chrome Azurol S and benzyldodecyldimethylammonium bromide was used for the analysis. A preliminary separation is made by extracting indium into butyl acetate from 5 M HBr solution. The selectivity of indium extraction and determination in the presence of macro- and micro components of soil was studied. Prior reduction of Fe (III) to Fe (II) with ascorbic acid prevents its co-extraction with indium. Indium was determined in synthetic mixtures corresponding to soil compositions and real samples of soil from different agricultural and industrial regions of Poland. The content of indium was found from the calibration graph (in the range, 0.12-0.48 μg/ml; r = 0.9991) obtained after extraction. The precision was satisfactory: % RSD (n = 6) ranged from 2.7 to 8.2. The average indium standard recovery ranged from 95 to 101%. Analysis using an ICP-OES method gave comparable results.

In this study, benthic flux measurements of inorganic nitrogen (i.e., [graphic removed] , [graphic removed] + [graphic removed] ) were made using a batch incubation system at different stations (i.e., shallow sandy macrophyte and unvegetated beds, and deep central mud) over four seasons in Lake Illawarra, NSW, Australia, to study the influence of different primary producers (i.e., seagrasses, microphytobenthos (MPB) and macroalgae) and/or different sediment types (i.e., sand or mud) on the benthic fluxes. In general, nutrient fluxes displayed typical diel variations, with lower flux out of sediments (release) or enhanced uptake by the sediment in the light, due to the photosynthetic activities of the plant-MPB-sediment community in Lake Illawarra during photosynthetic periods. A distinct seasonal pattern of inorganic-N fluxes was also observed (e.g., the marked difference between summers 2002 and 2003). This may be explained by the seasonal variations in the biomass and activity (growing or decay phases) of MPB, seagrass and macroalgae, which may influence their nutrient assimilation and alter the chemical conditions of surface sediments that influence the benthic geochemical processes and thus benthic nutrient fluxes. On an annual basis, unvegetated sediments displayed net DIN effluxes, while seagrass beds showed a net DIN uptake, and the highest DIN uptakes coincided with the largest standing crop of seagrass and/or macroalgae and the highest levels of benthic community production. This may be due to the enhanced denitrification and/or assimilation activity by rooted plants and macroalgae, and the effect is most efficient during periods of net growth (e.g., in Spring 2002).

An assessment of influent and effluent data from 24 wastewater treatment plants (WWTPs) in the state of Georgia with design capacities of 37,850 m³/d (10-mgd) or greater was undertaken. Twelve months of operating data from the 2003 calendar year were evaluated. The objectives of the study were to determine the effect of rainfall intensity on the volumetric flow rate to each WWTP and to determine the relationship between flow rate and the influent five-day, biochemical oxygen demand (BOD₅) and total suspended solids (TSS) concentrations. The relationships between rainfall intensity and influent BOD concentration, rainfall intensity and influent TSS concentration, influent BOD loading and effluent BOD concentration, and influent TSS loading and effluent TSS concentration were also evaluated. Moderate to strong correlations were observed between rainfall intensity and volumetric flow rate, volumetric flow rate and influent BOD and TSS concentrations, average monthly rainfall intensity and influent BOD and TSS concentrations, and between influent BOD and TSS loadings and effluent BOD and TSS concentrations. Weak correlations were observed for some of the relationships when applied to the complete data set however, stronger correlations were achieved by performing statistical analyses of variance and pooling subsets of the data. Peaking factors for flows and loadings were similar to those reported in the literature.

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.

Aquifer vulnerability assessments can be incorporated in groundwater contamination studies. Atmospheric pollutants as vanadium, V, can reach aquifers after soil deposition if the system is vulnerable. Vanadium concentrations were detected in soil and groundwater in Salamanca Mexico. V origin is related mainly to particulate emissions from a thermoelectric plant that is using fuel oil number 6 with high V content. To determine the V origin in groundwater, a soil and groundwater monitoring was carried out. A SINTACS vulnerability zoning was done. Vanadium in soil, emissions and groundwater is well correlated. The V input is associated to aquifer vulnerable zones.

Emergent wetland plant species may exhibit different nutrient removal efficiencies when grown in monoculture and mixed stands in constructed wetlands for tertiary purification of wastewater. A glasshouse study was conducted to investigate the influence of mono- and mixed-culture between Canna indica Linn and Schoenoplectus validus (Vahl) A. Löve & D. Löve on their growth in, and nutrient removal from, simulated wastewater in the surface water of vertical-flow wetland microcosms. Plants were grown for 50 days before imposing nutrient treatments that simulated secondary-treated municipal wastewater effluent with either low (17.5 mg N and 10 mg P per litre) or high (35.0 mg N and 20 mg P per litre) nutrient concentrations. Treatment solutions were renewed in weekly intervals. After 65 days of nutrient and plant treatments, the total and above-ground biomass was significantly (P < 0.01) greater in the high compared with the low nutrient treatment, but there were no significant differences in below-ground biomass. Significant (P < 0.01) differences in above-ground and below-ground biomass were observed, but no significant difference in total biomass was detected among plant treatments. The highest below-ground biomass was in monoculture of C. indica, whereas the highest above-ground biomass was in the monoculture of S. validus. The biomass of mixed-culture was intermediate to that in the two monoculture treatments. There was significant interspecific competition between C. indica and S. validus in mixed-culture, with C. indica being the superior competitor. The concentrations of N and P in plant tissues (except P in above-ground tissues) were significantly (P < 0.01) higher in the high than in the low nutrient treatment. The accumulation of N and P in above- and below-ground tissues largely reflected patterns of biomass allocation. No significant difference was observed between the nutrient treatments in nutrient removal efficiencies. Plant uptake was the major nutrient removal pathway in the wetland microcosms. Nutrient removal from simulated wastewater in mixed-culture was not greater than in mono-cultures, due to interspecific competition. The results suggested that plant nutrient uptake was the major removal mechanism at the establishment stands in the constructed wetlands.

Over 70 wood chemical plants operated in northern Pennsylvania between ca. 1890 and 1950, all located within 72 km of the New York state border. Their original purpose was to salvage the small unwanted hardwood trees left behind by the lumber mills, and to make charcoal, calcium acetate and methanol for a number of industrial uses via destructive distillation. At many old wood chemical plant sites, unknown quantities of wood tar remain as a residual contaminant and pose a pollution threat to aquatic life in nearby streams. Research on the composition and properties of residual wood tars from five abandoned industrial sites in Pennsylvania are described. Weathered wood tars were more viscous and contained fewer volatile and semivolatile organic compounds than did soil-buried tars. Phenol, 2-methylphenol (o-cresol), 4-methylphenol (p-cresol), and 2, 4-dimethylphenol were found in all sampled tars. These water-soluble phenolic compounds were released quasi-instantaneously in aqueous solution, followed by a slower rate of release, consistent with the behavior of similar compounds in other dense non-aqueous liquids. Air-exposed wood tar deposits developed a hard crust, which contained fewer volatiles and semivolatiles and had a higher softening point than other samples. These tars eroded to form a powdered soil colonized by lichens and mosses. Residual wood tar material found at one site was shown to be thermally altered, likely during the historical destruction of the chemical plant by fire. Recovered wood tar wastes have a relatively high heating value and may have use as a potential, but limited, alternate energy source.

Levels of heavy metals (chromium, copper, lead and cadmium) in water and sediments of the lower Salado River (Argentina) are presented and compared to Canadian and Argentinian environmental standards. Measurement of metal levels was performed using atomic absorption spectroscopy. In order to interpret analytical results, one way ANOVA, hierarchical cluster analysis and correlations were used. Geoaccumulation Index was used as a measure of metal pollution in sediments. There were differences between the accumulation of metals in sediments and water and the control sampling site. Heavy metals, especially chromium, copper and lead, appear to be an important problem to these freshwater environments.