Pesticide biodegradation was studied in soil samples of a representative small periurban production unit (Moreno District, Argentina). The mean periods required for the 50 % dissipation of chlorpyrifos (16 days ± 1 day), procymidone (3.7 days ± 0.6 day), and trifluralin (3.6 days ± 0.6 day) were significantly lower than those measured for reference soil samples of a close location, using doses similar to the manufacturer’s recommendation. A preliminary screening scheme for pesticide-degrading bacteria on horticultural soil allowed the isolation of nine culturable bacterial strains, eight of which belonged to Pseudomonas genus. In order to consider the influence of the variability of soil properties on the biodegradation results, humidity, organic matter, conductivity, pH, water retention volume, density, respiration, and total phosphorous content were studied for different soil samples, finding no significant differences in the performed analysis. Overall, although the horticultural activity alters the natural soil, pesticide contamination effects could be reversed by the autochthonous microbial community.

The ultimate goal of our study is to establish thin-layer chromatography (TLC) as a quick and simple method for identifying the type of refined petroleum products present in the environmental media. As a preliminary step, TLC chromatograms of different petroleum products, including gasoline, kerosene, and diesel, were characterized and compared. Methanol was determined as the optimum carrier solution in TLC analysis. The spherical-shaped TLC chromatogram of gasoline showed the longest migration distance, and thus the highest retardation factor (Rf) of 0.91. This was followed by that of kerosene (0.63) with an elliptical-shaped, and diesel (0.24) with an elongated trapezoid-shaped chromatogram. Rfof kerosene and diesel increased with the dilution factor, while gasoline showed a constant value. Additionally, it was observed that the TLC chromatograms of oils produced the same peak pattern with the corresponding petroleum products in gas chromatography (GC). A mixed sample of kerosene and diesel presented a triangular shaped chromatogram, underlining the need to consider the shape of chromatogram in addition to the Rfvalue, as an indicator of the petroleum type. The findings indicate that TLC has a huge potential to be used as a quick and reliable method for identifying the type of refined petroleum products in the environmental media.

A simple, rapid, sensitive, and inexpensive dispersive liquid–liquid microextraction method was developed for the determination of trace amounts of copper by flame atomic absorption spectrometry (FAAS). N,N′-bis-(2-hydroxy-5-bromobenzyl)-2-hydroxy-1,3-diiminopropane was used as the chelating ligand. Several analytical parameters affecting the microextraction efficiency such as, sample pH, volume of extraction solvent (carbon tetrachloride), concentrations of the chelating ligand and NaCl, and sample volume were investigated and optimized. The effect of the interfering ions on the recovery of copper was also examined. Under the optimum conditions, the detection limit (3σ) was 0.75 μg L⁻¹for copper with a sample volume of 10 mL, and a preconcentration factor of 20 was achieved. The relative standard deviation (R.S.D) for ten independent determinations of a 10 μg L⁻¹solution of Cu(II) was 2.3 %. In order to verify the accuracy of the developed method, different certified reference materials (SLRS-5, QCS-19, Rice flour unpolished high level of Cd NIES 10c) were analyzed and the results obtained were in good agreement with the certified values. The proposed method was applied to tap water, river water, seawater, rice flour, and wheat flour samples. The percentage recovery values for spiked water samples were between 95.4 and 108.4.

Surface mining for coal is responsible for widespread degradation of water resources and aquatic ecosystems in the Appalachian Region, USA. Because native topsoils are typically not retained on Appalachian mined sites, mine soils are usually composed of crushed overburden. This overburden tends to contribute high salinity loads to downstream aquatic systems. Also, loss of transpiration from forests and reduced infiltration associated with conventional reclamation procedures lead to altered water budgeting and stream morphology. To investigate the influence of the geologic composition of this overburden on water quality and tree growth, a series of experimental plots were constructed on a reclaimed surface mine site in eastern Kentucky, USA, in 2005. Treatments included unweathered GRAY sandstone, weathered BROWN sandstone, and MIXED sandstones and shale spoils. Plots were composed of end-dumped, uncompacted spoils and were designed to drain interflow through data acquisition stations for sampling purposes. Most water chemical parameters had stabilized across all treatments by 9 years after spoil placement. Discharge volume was not different among treatment types through the first 3 years after placement. However, 9 years after placement, seasonal variation in discharge on BROWN is more extreme than that on MIXED or GRAY. In addition, planted tree growth on BROWN has drastically outpaced growth on GRAY or MIXED, suggesting that evapotranspiration may be influencing seasonal variation in water discharged from BROWN. These results suggest that placement of brown weathered spoils when soil substitutes are required may lessen hydrologic impacts via improved tree growth and water utilization on surface-mined sites in Appalachia.

Industrialization and urbanization in central Europe since the middle of the nineteenth century led to changes in urban waste water disposal and thus, to an increasing nutrient impact of surface waters by human waste. Based on historical statistics and literature research, we have made a quantification of nutrient loads discharged to surface waters in central European river catchments for seven decades between 1878 and 1939. For both total nitrogen (TN) and total phosphorus (TP), nutrient inputs via point (urban) and diffuse (rural) pathways, nutrient removal by waste water treatment plants (WWTPs) and that during soil passage were quantified. The total nutrient inputs caused by human waste between 1880 and 1940 increased from 243 to 396 kt TN year⁻¹, and from 18 to 30 kt TP year⁻¹. In 1880, most of the inputs (92 % for TN and 93 % for TP) originated from diffuse pathways (cesspits). In 1940, 43 % of TN and 41 % of TP inputs originated from urban pathways (sewer systems). The total nutrient removal between 1880 and 1940 declined from 79 to 59 % for TN and from 86 to 66 % for TP. Consequently, waste water disposal shifted from diffuse to urban pathways. On the one side, this led to rising nutrient loads discharged to surface waters because of insufficient nutrient removal by the early WWTPs. Otherwise, nutrient concentration in groundwater under rural areas decreased by discharge human waste via sewer systems out of the cities.

A bentonite-based hydrogel was chemically modified to prepare a new effective adsorbent for the removal of phosphate from aqueous solutions using batch equilibrium experiments at the laboratory scale. The efficiency of the phosphate adsorption by the modified adsorbents followed the order: Al-Fe-hydrogel > Al-hydrogel > Fe-hydrogel > Rewoquate surfactant-hydrogel ≅ Irasoft surfactant-hydrogel > raw hydrogel. The amount of Fe and Al, as determined in proportion to the cation exchange capacity (CEC) of the hydrogel, was the most important parameter for optimizing the modification process by pillaring solutions. The results showed that the phosphate adsorption was rapid and pH independent. The removal of phosphate reached up to 99 % at the optimized conditions. The adsorption data were well fitted by Langmuir and Freundlich models. According to the Langmuir model, the maximum adsorption capacity of the phosphate on the Fe-Al-hydrogel was 14.29 mg L⁻¹. The removal of phosphate from an urban wastewater using the modified adsorbent was more than 99 %. The Fe-Al-hydrogel selectively adsorbed the phosphate from the solutions containing sulphate, bicarbonate, chloride, and nitrate. Based on the obtained results, the synthesized adsorbent could be used effectively to decontaminate the phosphate polluted water.

Drought conditions should magnify the effect of wastewater treatment plant (WWTP) effluent on river biogeochemistry. This study examined the impact of WWTP effluent on the Enoree River in the piedmont region of South Carolina during a period of significant drought. The Enoree River lacks impoundments, upstream agricultural runoff, and significant industrial point sources, so the single most important human influence on river chemistry is WWTP effluent. Water samples were collected from 28 locations on the Enoree River, 13 of its tributaries, and the effluent of four WWTPs. Effluent from the WWTP furthest upstream increased the salinity of the river and temporal variation and concentrations of most ions, especially nitrate, phosphate, sulfate, sodium, and chloride. The upstream WWTP set the downstream chemical composition of the river, with increasing proportions of chloride, sodium, and sulfate and decreasing proportions of dissolved silicon and bicarbonate. Downstream WWTPs had little or no impact on the chemical composition of the river. Mixing model results show that dilution was the dominant process of the downstream decrease in solute concentrations, but in-channel uptake mechanisms also contributed to declines in concentrations of nitrate, phosphate, and carbon dioxide. Despite dilution and uptake, the chemical signature of WWTP effluent was still evident 135 km downstream. These results lead to a better understanding of the effects of WWTP effluent on the biogeochemistry of rivers.

Adsorptive water purification methods were studied for the removal of phenol-type compounds (such as phenol/thymol) and humic acid applying sodium bentonite modified by cationic surfactant hexadecyltrimethylammonium bromide (HTAB). The effect of humic acid on adsorption of phenols was examined in pure and model thermal water. It was found that the efficiency of the removal of individual pollutants can be highly influenced if another pollutant is present. The main reason for the increased efficiency was identified by the means of infrared spectroscopy which proved that each pollutant modifies decisively the organophilicity of the clay surface. Furthermore, the studies performed in model thermal waters revealed that the presence of specific cations could further increase the removability of these pollutants.

Ombrotrophic peatlands are highly sensitive to atmospheric heavy metal deposition. Previous attempts to quantify peatland lead pollution have been undertaken using the inventory approach. However, there can be significant within-site spatial heterogeneity in lead concentrations, highlighting the need for multiple samples to properly quantify lead storage. Field portable x-ray fluorescence (FPXRF) continues to gain acceptance in the study of contaminated soil, but has not thus far been used to assess peatland lead contamination. This study compares lead concentrations in surface peat samples from the South Pennines (UK) derived using (a) FPXRF in the field, (b) FPXRF in the lab on dried samples and (c) ICP-OES analysis. FPXRF field and lab data are directly comparable when field measurements are corrected for water content, both can be easily used to estimate acid extractable lead using regression equations. This study is a successful demonstration of FPXRF as a tool for a time- and cost-effective means of determining the lead content of contaminated peatlands, which will allow rapid landscape scale reconnaissance, core logging, surface surveys and sediment tracing.

Concentration of methylmercury (MeHg) in different habitats and associated food chains may vary because of habitat characteristics that determine methylation and MeHg transfer. We examined MeHg levels in primary consumers from littoral, pelagial and profundal habitats of a boreal humic lake, and measured total mercury (TotHg) and MeHg in surface sediments at increasing depths. MeHg concentrations in primary consumers increased from profundal to littoral, a pattern which was mirrored by the surface sediment concentrations. Methylation potential (expressed as the ratio of MeHg to TotHg) was lower in profundal than in littoral sediments, suggesting that littoral sediments have higher net methylation rates. No specific MeHg-enriched entrance point in the littoral food chain was identified, however. High MeHg concentrations in littoral primary consumers and sediments suggest that shallow lake sediments are important for MeHg transfer to the aquatic food web in boreal humic lakes. Lake morphometry, most specifically the fraction of littoral, is hence likely to add to differences in MeHg bioaccumulation rates in lake food webs.