Highly sensitive determination of polybrominated diphenyl ethers in surface water by GC coupled to high-resolution MS according to the EU Water Directive 2008/105/EC.

The analysis of brominated flame retardants, such as polybrominated diphenyl ethers (PBDEs), has received increased interest because of their toxicity and ubiquity. According to European Union Directive 2008/105/EC, the development of highly sensitive and selective methods capable of determining PBDEs at low concentration levels (<0.5 ng/L) is necessary. In this work, an SPE method was developed for the analysis of the six PBDEs (BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154) specified by the aforementioned directive in surface waters. The analyses were performed by GC coupled to magnetic sector high-resolution MS. The conditions were also optimized to detect the target compounds in water samples at concentrations below the environmental quality standards established by European legislation. The validated method provided adequate linearity (determination coefficient, R(2) ≥ 0.9960), recovery (101-120%, except for BDE-47 at 5 ng/L, 127%), and precision values (RSD < 20%) at two fortification levels (0.2 and 5 ng/L). The method showed LODs and LOQs ranging from 0.02 to 0.05 and from 0.05 to 0.1 ng/L, respectively. The method was applied in surface water samples, allowing the determination of these compounds at the limits established by current legislation.

Priority organic compounds in wastewater effluents from the Mediterranean and Atlantic basins of Andalusia (Spain).

A comprehensive survey of the occurrence of organic compounds in 30 wastewater (WW) effluent samples from 21 urban wastewater treatment plants (WWTPs) from both secondary and tertiary treatments was carried out in the Mediterranean and Atlantic basins of the Andalusia region (south of Spain). For each sample, a total of 226 compounds including pesticides and some transformation products, polycyclic aromatic hydrocarbons (PAHs), phenolic compounds and volatile organic compounds (VOCs) were monitored with the aim of evaluating their occurrence in urban WW effluents. Compounds belonging to each class were detected. Among pesticides, insecticides such as clorfenvinphos and diazinon as well as herbicides such as diuron, sebuthylazine, terbuthylazine and terbuthylazine desethyl were the most frequently detected. The ubiquity of some compounds such as fluorene, phenanthrene and pyrene was also demonstrated. The compounds evaluated were detected at low concentrations (in general below 1 µg L(-1)), except 4-tert-octylphenol, which was detected at extremely high concentrations (up to 443 µg L(-1)). PAHs and VOCs were the compounds most frequently detected in the assayed samples, and they are the main sources of contamination in WWTPs, as well as some herbicides and transformation products.

Systematic study of the contamination of wastewater treatment plant effluents by organic priority compounds in Almeria province (SE Spain).

The occurrence of priority organic pollutants in wastewater (WW) effluents was evaluated in a semi-arid area, characterized by a high agricultural and tourism activity, as Almeria province (Southeastern Spain). Twelve wastewater treatment plants (WWTPs) were sampled in three campaigns during 2011, obtaining a total of 33 WW samples, monitoring 226 compounds, including pesticides, polycyclic aromatic hydrocarbons (PAHs), phenolic compounds and volatile organic compounds (VOCs). Certain banned organochlorine pesticides such as aldrin, pentachlorobenzene, o,p'-DDD and endosulfan lactone were found, and the most frequently detected pesticides were herbicides (diuron, triazines). PAHs and VOCs were also detected, noting that some of these pollutants were ubiquitous. Regarding phenolic compounds, 4-tertoctylphenol was found in all the WW samples at high concentration levels (up to 89.7 µg/L). Furthermore, it was observed that WW effluent samples were less contaminated in the second and third sampling periods, which corresponded to dry season. This evaluation revealed that despite the WW was treated in the WWTP, organic contaminants are still being detected in WW effluents and therefore they are released into the environment. Finally the risk of environmental threat due to the presence of some compounds in WWTP effluents, especially concerning 4-tertoctylphenol must be indicated.

Determination of 19 volatile organic compounds in wastewater effluents from different treatments by purge and trap followed by gas-chromatography coupled to mass spectrometry.

A rapid and simple methodology based on purge and trap with gas-chromatography coupled to triple quadrupole mass spectrometry has been developed for the analysis of 19 volatile organic compounds (VOCs) in wastewater (WW) effluents from four different treatments. The determination was carried out in the raw WW effluents, which were not submitted to any pre-treatment (e.g., filtration). A matrix effect study was also performed, concluding that solvent calibration was adequate to quantify VOCs in WW effluent samples containing a variety of suspended particulate matter. Adequate validation parameters were obtained with recovery values in the range 73-124% and precision values lower than 24%. Limits of quantification were established at 0.1 µg L(-1) for all VOCs. The proposed method was applied to the analysis of WW samples, detecting chloroform and toluene at concentrations ranging from 0.1 to 4.80 µg L(-1).

Comprehensive analysis of polycyclic aromatic hydrocarbons in wastewater using stir bar sorptive extraction and gas chromatography coupled to tandem mass spectrometry.

The objective of this study was the optimization and comparison of two extraction methods for the determination of polycyclic aromatic hydrocarbons (PAHs) in wastewater (WW). A distribution study of the target compounds between the aqueous phase and the suspended particulate matter (SPM) has been performed in order to establish whether the analysis of both phases is necessary. In this sense, the feasibility of stir bar sorptive extraction (SBSE) and solid-phase extraction (SPE) for the determination of 24 PAHs in WW samples has been evaluated. The results demonstrated the suitability of SBSE to perform a comprehensive analysis of liquid samples containing high amounts of SPM, such as in the determination of PAHs in WWs. A gas chromatography triple quadrupole mass spectrometry (GC-QqQ-MS/MS) method has been also optimized for the separation and detection of the target compounds, avoiding the co-elution of some groups of isomers, such as benzo[b], [j] and [k] fluoranthenes and indene[1,2,3-cd]pyrene/dibenz[a,h]anthracene. For that purpose, a specific capillary column developed for PAH determination was used. The SBSE procedure was validated and adequate parameters (such as recovery, linearity, precision, limits of detection and quantification) were obtained. Finally, the validated method was applied to the analysis of real samples collected from an experimental WW treatment plant, detecting some PAHs at concentrations in the range 0.007-0.022 µg L(-1).

Analysis and study of the distribution of polar and non-polar pesticides in wastewater effluents from modern and conventional treatments.

The analysis of a wide range of pesticides in wastewaters (WWs) undergoing different treatments (both modern and conventional) has been studied. The need for optimizing specific extraction methods for each WW effluent based on their physico-chemical characteristics has been considered. A distribution study was performed to establish if the filtration step before extraction is a correct procedure since pesticides can be more prone to be in the aqueous or the solid phase, depending on their hydrophobicity. This evaluation demonstrated that pesticides are distributed between the aqueous phase and the suspended particulate matter (SPM; e.g. pyrethroids are only found in the SPM). The proposed methodologies involved the determination of 39 polar and 139 non-polar pesticides using solid-phase extraction (SPE) and pressurized-liquid extraction (PLE) for the extraction of the aqueous phase and the SPM, respectively. Ultra high pressure liquid chromatography and gas chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS, GC-MS/MS) were used in the determination stage. WW samples from four different technologies were evaluated: membrane bioreactor, extended aeration, maturation pond and anaerobic pond. Validation data for the four effluents studied were generated, obtaining adequate precision values (estimated as % relative standard deviation, RSD) in almost all cases (<25%). The methods showed limits of detection at 0.01-0.20µgL(-1) and limits of quantification from 0.02 to 0.50µgL(-1). The proposed methods were applied to the analysis of real samples collected from an experimental WW treatment plant, detecting non-polar and polar pesticides at concentrations in the range 0.02-1.94µgL(-1) and 0.02-0.33µgL(-1), respectively.