Josep M. Bayona

Organotin contamination in sediments from the Western Mediterranean enclosures following 10 years of TBT regulation.

Organotin (OT) compounds, namely butyl and phenyl, were measured in 38 recent sediments collected in harbours of the Western Mediterranean Sea (Northern: 4 and Southern: 9) and domestic and industrial sewage disposal sites (Northern: 9 and Southern: 1). Butyltins were the predominant tin species identified as being tributyltin (TBT) widespread in the whole area which suggests recent inputs of OTs. The highest levels of TBT were detected in commercial harbours associated with inputs from large vessels (average value: 5.0 microg TBT g(-1). Moreover, relatively high TBT values were also detected in fishing and recreational boating areas (average level ca. 1.0 microg TBTg(-1)). Phenyltin derivatives occurred at lower levels than butyltins being the monophenyltin the predominant compound (average values 45-945 ng g(-1)). The large predominance of the phenyltin degradation products (i.e. mono and diphenyltin) over the parent compound (i.e. triphenyltin) suggests that there are almost no recent inputs of these compounds. Furthermore, a comparative study of the OT occurrence in the sewage sludge disposal sites offshore Barcelona and Almeria (domestic) and into the Tarragona harbour (industrial) shows that domestic primary sewage sludge effluents can contribute to coastal OT pollution (244ng TBT g(-1)). Nevertheless, sewage sludge is a secondary source of OT contamination in the coastal environment in comparison to commercial harbours. In a comparative study with previous data collected in the late 1980s, the present study reveals that OT regulations established in the Mediterranean region in 1991 on the use of TBT-based antifouling paints have been effective in marinas, but reveals a significant TBT contamination in commercial and fishing harbours.

Contaminant Removal Processes in Subsurface-Flow Constructed Wetlands: A Review

The main contaminant removal processes occurring in subsurface-flow constructed wetlands treating wastewater are reviewed. Redox conditions prevailing in the wetlands are analyzed and linked to contaminant removal mechanisms. The removal of organic matter and its accumulation in the granular medium of the wetlands are evaluated with regard to particulate and dissolved components and clogging processes. The main biological processes linked to organic matter transformation—aerobic respiration, denitrification, acid fermentation, sulfate reduction, and methanogenesis—are reviewed separately. The processes of removal of surfactants, pesticides and herbicides, emergent contaminants, nutrients, heavy metals and faecal organisms are analyzed. Advances in wetland modeling are presented as a powerful tool for understanding multiple interactions occurring in subsurface-flow constructed wetlands during the removal of contaminants.

Determination of methylmercury in fish and river water samples using in situ sodium tetraethylborate derivatization following by solid-phase microextraction and gas chromatography-mass spectrometry

Abstract A solid-phase microextraction (SPME) analytical procedure is described for the quantitative determination of methylmercury and labile Hg 2+ in fish and river water matrices, The analytical procedure involves aqueous-phase derivatization of ionic mercury species with sodium tetraethylborate in a sample vial and subsequent extraction with a silica fiber coated with poly(dimethylsiloxane). The mercury derivatives are desorbed in the splitless injection port of a gas chromatograph and subsequently analyzed by electron impact mass spectrometry. Both headspace SPME and aqueous-phase SPME are studied, and the linear range of the method spans several orders of magnitude for both procedures. The detection limits of the headspace SPME procedure for a 20-ml sample are 7.5 and 3.5 ng/l as Hg for CH 3 Hg + and Hg 2+ , respectively. The detection limits of aqueous-phase SPME for a 1.5-ml sample are 6.7 and 8.7 ng/l as Hg for CH 3 Hg + and Hg 2+ , respectively. Analyses of standard reference materials and river water sample demonstrate the suitability of this method for the determination of methylmercury and labile Hg 2+ .

Mass budget and dynamics of polycyclic aromatic hydrocarbons in the Mediterranean Sea

A mass budget was constructed to examine the status and dynamics of polycyclic aromatic hydrocarbons (PAHs) in the western Mediterranean Sea. Using gas chromatography-mass spectrometry, 11 PAHs have been quantified in atmospheric aerosols, rivers and seawater, sediment cores and sediment trap samples. Total PAH concentrations in Mediterranean aerosols range from 0.2 to 2 ng m−3, with 50–70% associated with the sub-micron particles. Maximum PAH concentrations were observed in winter when the concentrations were double those recorded in the spring. Total PAH inputs from the atmosphere were estimated to be from 35 to 70 t year−1 with a mean value of 47.5 t year−1 (wet/dry mean ratio of ∼2–3). Atmospherically-deposited PAH are dominated by the benzofluoranthenes. The total PAH riverine inputs amount to about 5.3−33 t year−1 from the Rhone river and 1.3 t year−1 from the Ebro river. The difference in these riverine fluxes is due to differences in annual water discharges and upstream land use. The total PAH accumulation rate in surficial sediments in the whole basin is estimated at 182 t year−1. Nearly 50% of the total PAHs accumulate in the 0–200 m water depth area supporting the importance of the coastal zone as a trap of terrigenous material and associated contaminants. Sediment trap experiments gave a mean residence time in the water column of total PAH (considering only particle settling) of 11 years, with higher residence times for high molecular weight PAHs. This supports the hypothesis that lower molecular weight PAHs are more efficiently removed from the water column. Water exchange resulted in a net outflow of 20 t year−1 and 2 t year−1 through the Gibraltar and Sicilian Straits, respectively. Atmospheric deposition and the Rhone River are the major contributors of PAH in the western Mediterranean. Sedimentation was identified as the major net output of PAH.

Preliminary screening of small-scale domestic wastewater treatment systems for removal of pharmaceutical and personal care products

Occurrence and removal efficiencies of 13 pharmaceuticals and personal care products (PPCPs) as well as BOD(5), TSS and NH(4)(+) were evaluated for the first time in thirteen onsite household secondary wastewater treatment systems, including two compact biofilters followed by Filtralite-P filter units, two biological sand filters, five horizontal subsurface flow and four vertical flow constructed wetlands. As expected, all systems removed TSS and BOD(5) efficiently (>95% removal). The PPCP removal efficiencies exceeded 80% with the exception of carbamazepine, diclofenac and ketoprofen because of their more recalcitrant characteristics. Despite no statistical differences in the PPCP removal were observed between the different systems evaluated, the vegetated vertical flow constructed wetlands which had unsaturated flow and hence better oxygenation, appeared consistently to perform better in terms of PPCP removal efficiency. The combined effects of vegetation and unsaturated water flow provide a higher tolerance to variations in loading rate and a consistent removal rate.

Comprehensive assessment of the design configuration of constructed wetlands for the removal of pharmaceuticals and personal care products from urban wastewaters

Seven mesocosm-scale constructed wetlands (CWs) of different configurations were operated outdoors for nine months to assess their ability to remove pharmaceuticals and personal care products (PPCPs) from urban wastewaters. CWs differed in some design parameters, namely the presence of plants, the species chosen (i.e., Typha angustifolia vs Phragmites australis), flow configuration (i.e., surface flow vs subsurface flow) and the presence of a gravel bed. A nearby conventional activated-sludge wastewater treatment plant (WWTP) fed with the same sewage was simultaneously monitored for comparison. The PPCPs ketoprofen, naproxen, ibuprofen, diclofenac, salicylic acid, carbamazepine, caffeine, galaxolide, tonalide and methyl dihydrojasmonate were monitored. The presence of plants favoured the removal of some PPCPs. The performance of the mesocosm studied was compound-dependant, soilless CWs showing the highest removal efficiency for ketoprofen, ibuprofen and carbamazepine, while free-water CWs with effluent leaving through the bottom of the tank performed well for the degradation of ketoprofen, salicylic acid, galaxolide and tonalide. Finally, subsurface horizontal flow CWs were efficient for the removal of caffeine. Significant linear correlations were observed between the removal of some PPCPs and temperature or redox potential. Hence, microbiological pathways appear to be the most probable degradation route for PPCPs in the CWs studied.

Assessment of full-scale natural systems for the removal of PPCPs from wastewater in small communities.

This study assessed the ability to remove pharmaceuticals and personal care products (PPCPs) of three different full-scale hybrid pond-constructed wetlands and a conventional wastewater treatment plant (WWTP). The four systems were fed with primary-treated urban wastewaters. The three hybrid systems consisted of several different subsystems (ponds, surface flow constructed wetlands and horizontal subsurface flow constructed wetlands) connected in series, and their PPCP degradation efficiency was monitored. In addition, the enantiomeric behaviour of ibuprofen was studied in all the subsystems. The hybrid systems were at least as efficient in PPCP removal as the WWTP, removal efficiencies mainly exceeding 70%. Moreover, enantiomeric analysis indicates that ibuprofen removal followed a predominantly aerobic and microbiological pathway. Constructed wetlands and ponds are therefore successful technologies for removing PPCPs from wastewater and the most significant removal process in these systems is biologically mediated.

Screening of 47 organic microcontaminants in agricultural irrigation waters and their soil loading

Reclaimed water usage for crop irrigation is viewed both as an excellent sustainable water source and as a potential entrance for emerging organics into the food chain. This concern is backed by the already documented pollutant crop uptake potential. In the present study, irrigation waters used in agricultural fields (Torroella de Montgri, NE Spain) were screened for 47 analytes in a two year study (2007-2008). A total of 26 contaminants belonging to different chemical classes namely, pesticides, pharmaceuticals, personal care products, phenolic estrogens, antioxidants and disinfection by-products, were detected. Marked differences in concentration trends for the different chemical classes were evidenced from 2007 to 2008, and attributed to a persistent drought endured by the region in 2008. Also, loading mass rates of chemical classes were estimated based on crop irrigation regimes and they ranged from 0.8 to 121.3 g ha(-1) per crop cycle. These values were contrasted with those obtained for other water sources from countries where crop irrigation is commonly practiced. Finally, crops grown under these irrigation regimes, namely alfalfa and apple, were analyzed and 5 anthropogenic compounds were identified and quantitated, whose concentrations ranged from 13.9 to 532 ng g(-1) (fresh weight).

Part-per-Trillion Determination of Pharmaceuticals, Pesticides, and Related Organic Contaminants in River Water by Solid-Phase Extraction Followed by Comprehensive Two-Dimensional Gas Chromatography Time-of-Flight Mass Spectrometry

An analytical procedure based on comprehensive two-dimensional gas chromatography (GC x GC) coupled with time-of-flight mass spectrometry (TOF-MS) for the simultaneous determination of 97 organic contaminants at trace concentration in river water is presented. The target analytes included 13 pharmaceuticals, 18 plasticizers, 8 personal care products, 9 acid herbicides, 8 triazines, 10 organophosphorous compounds, 5 phenylureas, 12 organochlorine biocides, 9 polycyclic aromatic hydrocarbons (PAHs), and 5 benzothiazoles and benzotriazoles. The best resolution of the target analytes in the contour plots was obtained when a nonpolar stationary phase was used in the first dimension and polar one in the second. However, in the opposite configuration, polar-nonpolar, the retention time in the second dimension exhibited a strong correlation with the log Kow (p < 0.01), and it was proposed as an additional identification criteria. The developed methodology is based on a polymeric solid-phase extraction followed by in GC-port methylation and GC x GC/TOF-MS determination. Moreover, limits of detection (LODs) and quantification (LOQs) ranged from 0.5 to 100 ng/L and from 2 to 185 ng/L, respectively. Repeatability was always lower than 20%. Finally, the developed method has been successfully applied to the determination of incurred target analytes in four river waters subjected to a different anthropogenic pressure.

Assessment of the pharmaceutical active compounds removal in wastewater treatment systems at enantiomeric level. Ibuprofen and naproxen.

The enantioselective degradation of ibuprofen and naproxen enantiomers was evaluated in five different wastewater treatment systems, including three constructed wetlands (vertical- and horizontal-flow configurations), a sand filter and an activated sludge wastewater treatment plant. In addition, injection experiments were carried out with racemic ibuprofen at microcosm- and pilot-scale constructed wetlands. Ibuprofen and naproxen have an asymmetric carbon atom and, consequently, two enantiomeric forms (i.e. S and R). The enantiomeric fraction (EF=S/(S+R)) in the raw sewage and effluents of various wastewater treatments were found to be compound-dependent (i.e. ibuprofen: EF(influent)=0.73-0.90, EF(effluent)=0.60-0.76; naproxen: EF(influent)=0.88-0.90, EF(effluent)=0.71-0.86). Of the two chiral pharmaceuticals, naproxen was the only one whose effluent EF correlated with its removal efficiency (p<0.05). The lack of correlation found for ibuprofen was attributable to the fact that its enantioselective degradation kinetics were different under prevailing aerobic and anaerobic conditions. Injection experiments of ibuprofen in constructed wetlands at microcosm and pilot-scale followed similar trends. Hence, under prevailing aerobic conditions, S-ibuprofen degraded faster than R-ibuprofen, whereas under prevailing anaerobic conditions, the degradation was not enantioselective. In summary, the naproxen EF measurements in wastewater effluents show that naproxen is a suitable alternative for evaluating the removal efficiency of treatment systems because its enantioselective degradation is similar under prevailing aerobic and anaerobic conditions.