Occurrence and distribution of pharmaceuticals in surface water, suspended solids and sediments of the Ebro river basin, Spain

The occurrence of 43 pharmaceuticals belonging to predominant therapeutic classes and their distribution in surface water, suspended solids and sediments has been investigated in the Ebro river basin in the Northeast of Spain. WWTP effluents were found to be a main source of contamination and the spatial distribution was affected by the river flow at the sampling point and corresponding dilution factor, resulting in higher concentrations and higher loads in small tributary rivers than in the Ebro river. The study showed that some compounds are preferentially found bound to suspended solids and not detected in river water. Generally, compounds with basic characteristics (pKa > 7) showed higher tendency to bind to suspended solids. The sediment samples generally presented lower concentrations than suspended solids.     

Development,validation, and application of a method for the GC-MS analysis of fipronil and three of its degradation products in samples of water,soil, and sediment

A method for the identification and quantification of pesticide residues in water, soil, and sediment samples has been developed, validated, and applied for the analysis of real samples. The specificity was determined by the retention time and the confirmation and quantification of analyte ions. Linearity was demonstrated over the concentration range of 20 to 120 µg L^?1, and the correlation coefficients varied between 0.979 and 0.996, depending on the analytes. The recovery rates for all analytes in the studied matrix were between 86% and 112%. The intermediate precision and repeatability were determined at three concentration levels (40, 80, and 120 µg L^?1), with the relative standard deviation for the intermediate precision between 1% and 5.3% and the repeatability varying between 2% and 13.4% for individual analytes. The limits of detection and quantification for fipronil, fipronil sulfide, fipronil-sulfone, and fipronil-desulfinyl were 6.2, 3.0, 6.6, and 4.0 ng L^?1 and 20.4, 9.0, 21.6, and 13.0 ng L^?1, respectively. The method developed was used in water, soil, and sediment samples containing 2.1 mg L^?1 and 1.2% and 5.3% of carbon, respectively. The recovery of pesticides in the environmental matrices varied from 88.26 to 109.63% for the lowest fortification level (40 and 100 µg kg^?1), from 91.17 to 110.18% for the intermediate level (80 and 200 µg kg^?1), and from 89.09 to 109.82% for the highest fortification level (120 and 300 µg kg^?1). The relative standard deviation for the recovery of pesticides was under 15%.     

Sorption of alpha and beta hydrophobic endosulfan in a Vertisol from southeast region of Turkey

Endosulfan has been applied to control numerous insects in a variety of food and non-food crops. Limited information is available on dynamics of this pesticide in the soil. The objective of this research was to determine the adsorption–desorption behavior of the alpha (α) and beta (β) endosulfan in a Vertisol from the southeast region of Turkey, where cotton is the main crop in the large irrigated lowlands. The α and β endosulfan were adsorbed considerably and Freundlich adsorption–desorption isotherms fitted the α and β endosulfan data (R² > 0.98). Freundlich adsorption coefficients (K_f) for the α endosulfan ranged between 21.63 and 16.33 while for the β endosulfan they were between 14.01 and 17.98 for the Ap and Bw2 horizons. The difference of K_f values of α and β endosulfan for two horizons were explained with the slight difference in the amount of organic matter and clay, but considerable difference in Fe contents of the two horizons. Alpha and β endosulfan K_fd values were 118.03 and 45.81 for the Ap and 48.08 and 68.71 for the Bw2 horizons. Higher adsorption and desorption behavior of the endosulfan isomers for the same horizon was attributed to poor physical bonding between the endosulfan molecule and the surfaces of fundamental soil particles. This fact is thought to increase the effective use of endosulfan in agriculture with a possibility of its movement to the surface and groundwater in the Vertisol studied.     

Nitrogen deposition effects on Mediterranean-type ecosystems: an ecological assessment

We review the ecological consequences of N deposition on the five Mediterranean regions of the world. Seasonality of precipitation and fires regulate the N cycle in these water-limited ecosystems, where dry N deposition dominates. Nitrogen accumulation in soils and on plant surfaces results in peaks of availability with the first winter rains. Decoupling between N flushes and plant demand promotes losses via leaching and gas emissions. Differences in P availability may control the response to N inputs and susceptibility to exotic plant invasion. Invasive grasses accumulate as fuel during the dry season, altering fire regimes. California and the Mediterranean Basin are the most threatened by N deposition; however, there is limited evidence for N deposition impacts outside of California. Consequently, more research is needed to determine critical loads for each region and vegetation type based on the most sensitive elements, such as changes in lichen species composition and N cycling.     

Pentachlorophenol association with fulvic acids from recycled wastes

The apparent water solubility of pentachlorophenol was measured at pH=6 and at 25 degrees C in pure water, aqueous solutions of three salts (NaCl, KNO(3) and CaCl(2) at 0.010, 0.10 and 1.0M) and in aqueous solutions of three fulvic acids samples extracted from a natural soil (sFA), composted sewage sludge (csFA) and composted livestock's material (lsFA). A solubility enhancement method was developed for the measurement of partition coefficients (K(oc), L/kg organic carbon). Pentachlorophenol associates strongly with the fulvic acid samples and the calculated K(oc) were the following (averages and standard deviations): (sFA) (211+/-22) x 10(2), (csFA) (253+/-26) x 10(2), (lsFA) (235+/-10) x 10(2). For comparison purposes the K(oc) for pyrene were also calculated for the three FA samples and were the following: (sFA) (119+/-10) x 10(2), (csFA) (239+/-21) x 10(2), (lsFA) (92+/-10) x 10(2). The analysis of variance (one-way ANOVA) of the effect of the type of FA sample on the solubilization of pentachlorophenol and pyrene shows that this factor causes significant differences on the aqueous solubilization of these two organic substances.     

Discriminating the pH toxicity to Poecilia reticulata Peters, 1859 in the Dunas Lake (Camaçari, BA, Brazil)

Toxic potential of the pH reduction to fingerlings of Poecilia reticulata, through acute toxicity bioassays, as well as the influence of increased pH on the toxicity were assessed. Acid lake samples (Dunas Lake) were collected during 19 months, and assessed with following treatments: water at local pH (+/-3.0) and samples with modified pH to 3.5, 3.8, 4.0, 4.3, 4.6, 5.0, 5.5, 6.0, and 6.5. Culture water samples with pH reduced to 3.0 were also assessed. Newborn P. reticulata were exposed during 96h, and dead/immobile organisms were counted at various time intervals during exposure (short intervals in the beginning and long towards the end). Mean results of LT(50) and confidence intervals from the Dunas Lake and control water with reduced pH were 1.36 (+/-0.48)h, and 1.03 (+/-0.50)h, respectively, with no statistical difference. Samples with increased pH showed a significant reduction in toxicity, with no toxicity detected at pH 6.0 and higher. Relationship between pH and lethal toxicity for fingerlings of P. reticulata demonstrated that pH exerted a strong effect on the survival of this species at the Dunas Lake, explaining about 80% of the toxicity observed.