Agricultural runoff is a major non-point source pollutant and is the leading impairment of streams and rivers in the USA. This study examined the effects of agricultural, forest and urban land cover on water quality at the watershed level. Forty-three catchments ranging from 12 to 50 km2 were selected based on a land cover gradient within Lower Kaskaskia River Watershed in Illinois. Grab samples were collected and analyzed for nutrients, bacteria, and total suspended solids (TSS). Forest land cover was included in six of the ten regression models produced. Four of these regression models were for base flow conditions, suggesting that forest land cover had a significant impact on base flow water quality. Urban land cover was also included in six of the regression models. However, the majority were during storm flow conditions implying urban land cover had a greater impact on storm flow conditions. Watersheds were further categorized into agriculture, village, and urban watersheds. During base flow conditions agriculture watersheds had significantly higher TSS concentrations and urban watersheds had significantly higher ortho-P concentrations. In all watersheds, ortho-P concentrations were above the statewide 95th percentile for Illinois streams. Escherichia coli levels during storm conditions exceeded the national US EPA criteria.

A multiphase model based on the Mackay-type level II fugacity model has been used to predict the behaviour and final environmental concentrations of some of the more consumed pharmaceuticals in Spain. The model takes into account the mean rate of consumption of pharmaceuticals, the percentage of pharmaceutical metabolised, the formation of the corresponding glucuronide, which is assumed to be hydrolysed back to the parent molecule, the partial degradation of each pharmaceutical in a conventional sewage treatment plant, and the fate of these substances in a regional model environmental system. Predicted environmental concentrations in air, water, soil, sediments and suspended matter, and the corresponding residence time for each pharmaceutical have been obtained by application of the model. The predicted concentrations of pharmaceuticals in the water phase are of the same order than the measured experimentally, showing that the simple model used to predict the environmental concentrations is suitable for modelling the environmental fate of high water soluble and low volatile organic compounds such as pharmaceuticals products.

Lake Hallstättersee is a holomictic alpine lake, which is influenced by salt mining since the middle Bronze Age. Beside the constant saline waste water load, two massive brine spills loaded the lake with additional 16,900 tons sodium chloride (≈10,250 tons Cl−) from 1977 to 1979 and 3,000 tons salt (≈1,820 tons Cl−) in 2005. The effect of waste water intrusions from salt mining on stratification of Lake Hallstättersee was analysed over a period of 40 years. Water density, dissolved oxygen and total phosphorus (TP) concentrations were measured and an exponential model was fitted to describe the wash-out of chloride from Lake Hallstättersee after the brine spills. Furthermore, the time required returning to holomixis and steady chloride content after the second brine spill was estimated. During the whole sampling period the minimum and maximum volume-weighted annual mean chloride concentrations were 23.58 mg/L in 1979 and 3.19 mg/L in 1998. However, the mixing regime of Lake Hallstättersee, as well as the chloride concentrations, varied considerably and exhibited three holomictic and three meromictic periods between 1970 and 2009. Holomictic periods were observed when the yearly density gradient was below 0.06 kg/m3, deepwater oxygen in spring above 4 mg/L and consequently declining TP concentration in the deepest water layer below 60 mg/m3, otherwise meromictic periods were observed. Our study showed that Hallstättersee was 13 years ectogenic meromictic and 27 years holomictic during the study period.

The effects of municipal sewage sludge applied on topsoil and understory vegetation (Molinia caerulea (L.) Moench) were studied in a maritime pine forest located in the South West of France (Landes of Gascogne). Understory response to sludge application is important as sludge addition to forest could increase competition with pine and affect herbivorous wildlife through incorporation of heavy metals in the food chain. The experiment was conducted in a young stand of maritime pines. The experimental design consisted of three 0.1-ha plots. One plot received composted sludge, one plot received liquid sludge, and one control plot received no sludge. Liquid sludge and composted sludge were applied on the basis of 3 tons dry matter sludge per hectare and per year. After 2 years of sludge application, we observed the following: (1) a significant increase in total concentrations of the following major and trace elements in the topsoil (layer 0–20 cm) [organic carbon (+140%), nitrogen (+140%), and lead (+80%)] and (2) no significant accumulation of trace elements in M. caerulea except nickel, which increased moderately (+40%) following application of composted sludge. These initial results need to be completed (1) by the assessment of long-term effects and dynamics of trace elements with additional applications of sludge and (2) by analyzing secondary understory species to determine if understory response to sludge application is more dependant on species than on soil parameters and sludge type.

The concentration of p-cresol and p-ethylphenol, two malodorants typical of swine waste, were measured at 0.5 and 1.5 m above a waste treatment lagoon during two separate campaigns encompassing late winter through early spring and late spring through early summer. Concomitant collection of air temperatures, humidities, insolation, and wind speeds, as well as water column temperatures were done so that heat fluxes could be computed using an energy budget method and Bowen ratio estimates. The empirical model that was found to correlate best with variations in malodorant concentrations and gradients above the lagoon had the terms describing evaporation from the lagoon surface and net available energy at the lagoon surface. Emissions were found to be much higher during the cool season than the warm season. This was despite much higher evaporation rates during the warm season. This could be explained by much lower lagoon concentrations of the malodorants in the warm season than in the cool season. Results of this work are being used to determine appropriate models to estimate malodorant emissions from lagoons and devise techniques for the abatement of nuisance emissions.

Biological degradation rates of six pharmaceuticals and personal care products were examined in soil from a land application site and in adjacent soil with no prior history of effluent exposure. Microbial degradation rates were compared over 2 weeks under standing water or saturated conditions and draining conditions after having been saturated for 3 days. Biological degradation of 17β-estradiol exhibited rapid rates of biological degradation under both saturated and draining conditions. Half-lives for 17β-estradiol ranged from 1.5 to 4 days; 66–97% was lost from the soils. Estriol showed a pattern of biological degradation in both saturated and draining conditions though the half-lives were longer (8.7–25.9 days) than those observed for 17β-estradiol. Twenty-eight percent to 73% of estriol was lost over the 14 days treatment period. Estrone and 17α-ethinylestradiol exhibited slower rates of biological transformation under saturated and draining conditions. Half-lives for estrone ranged between 27.5 and 56.8 days with loss of at most 21%. 17α-ethinylestradiol exhibited half-lives of 22.6–207 days. Half-life data for ibuprofen ranged from 30.4 to 1,706.4 days in this experiment. Losses of up to 17% were observed in draining soils. Triclosan loss was at most 10%, and half-lives were 70.9–398.8 days. In all cases, soils that were draining from saturated conditions exhibited faster degradation rates than soils that remained saturated. Prior exposure of the soil to effluent did not always result in higher biological degradation rates.

The goal of the present work was to increase our knowledge on the behavior of manganese and nickel in soil within a Mediterranean environment. The study assessed the concentration levels of Mn and Ni (heavy metals selected for their essential role in the development of plants) in 250 soil horizon samples within 125 soil profiles of undisturbed soils in La Rioja (Spain). The study was undertaken to investigate and predict Mn and Ni concentrations on a regional scale. The analysis of spatial distribution of the elements was found to be affected by the nature of bedrock and, to a lesser extent, the anthropogenic origin. The variation of vertical distributions can be related, first, to natural sources—mainly the bed rocks—and, second, to soil processes. The geographical distribution of soil Mn is important to agriculture, nutrition, and health. Soil Mn and Ni maps of the area were elaborated, using geostatistics and geographic information systems. Mapping of geographical distributions will be useful in future research to determine regional patterns of Mn and Ni bioavailability, Mn and Ni deficiencies, and the possible consequences of land disposal of Mn- and Ni-laden wastes.

The heterogeneous photocatalytic water purification process has gained wide attention due to its effectiveness in degrading and mineralizing the recalcitrant organic compounds as well as the possibility of utilizing the solar UV and visible light spectrum. This paper aims to review and summarize the recently published works in the field of photocatalytic oxidation of toxic organic compounds such as phenols and dyes, predominant in wastewater effluent. In this review, the effects of various operating parameters on the photocatalytic degradation of phenols and dyes are presented. Recent findings suggested that different parameters, such as type of photocatalyst and composition, light intensity, initial substrate concentration, amount of catalyst, pH of the reaction medium, ionic components in water, solvent types, oxidizing agents/electron acceptors, mode of catalyst application, and calcinations temperature can play an important role on the photocatalytic degradation of organic compounds in water environment. Extensive research has focused on the enhancement of photocatalysis by modification of TiO2 employing metal, non-metal, and ion doping. Recent advances in TiO2 photocatalysis for the degradation of various phenols and dyes are also highlighted in this review.

The main objective of this study was to evaluate the contribution of sorption to the removal of two commonly used antibiotics (amoxicillin and ciprofloxacin) from wastewater. These antibiotics are excreted in large quantities with more than 75% of them being unmetabolized and are therefore likely to end up in domestic wastewater in significant quantities. The specific objectives were to determine the sorption behavior in synthetic wastewater (SWW), the effect of pH and contribution of microbial surfaces, to the sorption of these antibiotics. The SWW, adjusted to various pH levels, was used and sorption kinetics conducted at 100 and 250 μg L−1 concentrations. Adsorption isotherms were determined at different pH levels. The SWW (pH 6.6) was inoculated with Rhodococcus sp. B30 strain to determine the contribution of microbial surfaces to sorption. Generally, both antibiotics revealed a decrease in sorption with pH increase, suggesting that lowering the solution pH of the wastewater may reduce their amounts in wastewater solution. Comparatively, ciprofloxacin exhibited higher sorption than amoxicillin. The sorption distribution coefficient (K d) values for ciprofloxacin ranged from 0.4356 to 0.8902 L g−1, with pH = 5.5 exhibiting the highest K d, while that for amoxicillin ranged from 0.1582 to 0.3858 L g−1 with the highest K d at pH = 3.5. There was a significant difference (p < 0.05) in K d values between various pH levels for both antibiotics except between the pH of 5.5 and 6.6. Both antibiotics were not degraded within 48 h by Rhodococcus sp. B30 strain. These results indicate that degradation may not be the major process of removal of compounds from wastewater treatment plants and hence the importance of sorption as an intervention technique.

Sorption and desorption of Hg(II) on clay minerals can impact the biogeochemical cycle and bio-uptake of Hg in the environment. We studied the kinetics of the desorption of Hg(II) from kaolinite as affected by oxalate and cysteine, representing the ligands with carboxylic and thiol groups of different affinities for Hg(II). The effects of pH (3, 5, and 7), ligand concentration (0.25 and 1.0 mM), and temperature (15°C, 25°C, and 35°C) on the Hg(II) desorption were investigated through desorption kinetics. Our study showed that the Hg(II) desorption was pH dependent. In the absence of any organic ligand, >90% of the previously adsorbed Hg(II) desorbed at pH 3 within 2 h, compared to <10% at pH 7. Similar results were observed in the presence of oxalate, showing that it hardly affected the Hg(II) desorption. Cysteine inhibited the Hg(II) desorption significantly at all the pH tested, especially in the first 80 min with the desorption less than 20%, but the inhibition of the desorption appeared to be less prominent afterwards. The effect of the ligand concentration on the Hg(II) desorption was small, especially in the presence of oxalate. The effect of temperature on the Hg(II) desorption was nearly insignificant. The effect of the organic acids on the Hg(II) sorption and desorption is explained by the formation of the ternary surface complexes involving the mineral, ligand, and Hg(II). The competition for Hg(II) between the cysteine molecules adsorbed on the particle surfaces and in the solution phase probably can also affect the Hg(II) desorption.