Ethel Eljarrat

Recent advances in the mass spectrometric analysis related to endocrine disrupting compounds in aquatic environmental samples.

An overview of mass spectrometric methods used for the determination of endocrine disrupting compounds (EDCs) in environmental samples is presented. Among the EDCs we have selected five groups of compounds that are of priority within European Union and US research activities: alkylphenols, polychlorinated compounds (dioxins, furans and biphenyls), polybrominated diphenyl ethers, phthalates and steroid sex hormones. Various aspects of current LC-MS and GC-MS methodology, including sample preparation, are discussed.

Analysis and environmental levels of endocrine-disrupting compounds in freshwater sediments

An overview of analytical methods for target endocrine-disrupting compounds (EDCs) in freshwater sediments is presented. Among the EDCs we have selected five groups of compounds that are of priority within European Union and USA research activities: alkylphenols, polychlorinated compounds (dioxins, furans and biphenyls), polybrominated diphenyl ethers, phthalates and steroid sex hormones. Various aspects of current analytical methodology, such as sample preparation, extraction, purification and final determination, are discussed. Levels found in freshwater sediment are reviewed.

Determination of PBDEs, HBB, PBEB, DBDPE, HBCD, TBBPA and related compounds in sewage sludge from Catalonia (Spain)

The objective of this study was to determine different brominated flame retardants (BFRs) in sewage sludge produced in 17 wastewater treatment plants (WWTPs) located in the Northeast of Spain. A total of eight polybrominated diphenyl ether (PBDE) congeners, from tri- to deca-BDEs, were analyzed. The emerging BFR compounds, hexabromobenzene (HBB), pentabromoethylbenzene (PBEB) and decabromodiphenylethane (DBDPE) were also analyzed. The instrumental methodology for the analysis was based on gas chromatography coupled to mass spectrometry with negative chemical ionization (GC-NICI-MS). Moreover, liquid cromathography-quadrupole linear ion trap mass spectrometry (LC-QqLIT-MS/MS) was applied for the determination of hexabromocyclododecanes (HBCDs), tetrabromobisphenol A (TBBPA) and their related compounds, bisphenol A (BPA), monobromobisphenol A (MonoBBPA), dibromobisphenol A (DiBBPA) and tribromobisphenol A (TriBBPA). The most abundant PBDE congener in these sewage sludge samples was BDE-209, with levels ranging from nd to 2303 ng/g dw. In addition, a significant concentrations of DBDPE were also detected, nd-257 ng/g dw, due to their increase production as a Deca-BDE substitute. The emerging compounds HBB and PBEB were detected in 4 WWTPs and their concentrations ranged between nd-5.71 and nd-2.33 ng/g, respectively. TBBPA was detected in quantifiable levels in 15 of the 17 WWTPs analyzed, in concentration range of nd-472 ng/g dw, whereas HBCDs were only found in 8 WWTPs in lower concentrations, between nd and 97.5 ng/g dw. Based on the analysis of sewage sludge samples from different WWTPs and in order to evaluate the impact of these contaminants in the environment, an estimation of BFRs accumulated in the total sewage sludge produced in Catalonia was carried out, with values of 57.8 kg/year, 6.76 kg/year, 13.5 kg/year, 1.56 kg/year, 0.18 kg/year and 0.02 kg/year for PBDEs, DBDPE, TBBPA, HBCDs, HBB and PBEB respectively.

Dechlorane Plus and Related Compounds in Peregrine Falcon (Falco peregrinus) Eggs from Canada and Spain

Concentrations of Mirex, Dechlorane (Dec) Plus (DP), Dec 602, Dec 603, and Dec 604 were significantly higher in peregrine falcon (Falco peregrinus) eggs from Canada than Spain, with the former having the only measurable concentrations of the dechlorinated DP products, decachloropentacyclooctadecadiene (aCl10DP) and undecachloropentacyclooctadecadiene (aCl11DP). Large variations also occurred in the in ovo concentrations of the DP monoadduct, DPMA. This is the first study to report the accumulation and metabolism of DP by peregrines, both DP and dechloranes in European biota, as well as dechloranes in a terrestrial organism and one at the top of the food web. The geographical differences in the measured in ovo concentrations reflect local exposure of the adult peregrines on their breeding grounds, likely differences in diet of the adults, the production of DP on the Niagara River, and the greater use of Mirex and dechloranes as flame retardants in North America than Europe.

First Determination of UV Filters in Marine Mammals. Octocrylene Levels in Franciscana Dolphins

Most current bioexposure assessments for UV filters focus on contaminants concentrations in fish from river and lake. To date there is not information available on the occurrence of UV filters in marine mammals. This is the first study to investigate the presence of sunscreen agents in tissue liver of Franciscana dolphin (Pontoporia blainvillei), a species under special measures for conservation. Fifty six liver tissue samples were taken from dead individuals accidentally caught or found stranded along the Brazilian coastal area (six states). The extensively used octocrylene (2-ethylhexyl-2-cyano-3,3-diphenyl-2-propenoate, OCT) was frequently found in the samples investigated (21 out of 56) at concentrations in the range 89-782 ng·g(-1) lipid weight. São Paulo was found to be the most polluted area (70% frequency of detection). Nevertheless, the highest concentration was observed in the dolphins from Rio Grande do Sul (42% frequency of detection within that area). These findings constitute the first data reported on the occurrence of UV filters in marine mammals worldwide.

Pyrethroids in human breast milk: Occurrence and nursing daily intake estimation.

There is an assumption that pyrethroid pesticides are converted to non-toxic metabolites by hydrolysis in mammals. However, some recent works have shown their bioaccumulation in human breast milk collected in areas where pyrethroids have been widely used for agriculture or malaria control. In this work, thirteen pyrethroids have been studied in human breast milk samples coming from areas without pyrethroid use for malaria control, such as Brazil, Colombia and Spain. The concentrations of pyrethroids ranged from 1.45 to 24.2 ng g⁻¹ lw. Cypermethrin, λ-cyhalothrin, permethrin and esfenvalerate/fenvalerate were present in all the studied samples. The composition of pyrethroid mixture depended on the country of origin of the samples, bifenthrin being the most abundant in Brazilian samples, λ-cyhalothrin in Colombian and permethrin in Spanish ones. When the pyrethroid concentrations were confronted against the number of gestations, an exponential decay was observed. Moreover, a time trend study was carried out in Brazil, where additional archived pool samples were analyzed, corresponding to years when pyrethroids were applied for dengue epidemic control. In these cases, total pyrethroid levels reached up to 128 ng g⁻¹ lw, and concentrations decreased when massive use was not allowed. Finally, daily intake estimation of nursing infants was calculated in each country and compared to acceptable WHO levels. The estimated daily intakes for nursing infants were always below the acceptable daily intake levels, nevertheless in certain samples the detected concentrations were very close to the maximum acceptable levels.

Dechlorane Plus and related compounds in aquatic and terrestrial biota: a review.

Dechlorane Plus, dechlorane 602, dechlorane 603 and dechlorane 604 are flame retardants that have been used for a long time as a substitute for mirex, but they have not been noticed as environmental contaminants until recently (2006). Regardless of their large molecular size and very high lipophilicity (log KOW > 9), Dechlorane Plus and related compounds have been detected in different aquatic and terrestrial species, supporting their bioaccumulation and biomagnification. Moreover, some studies showed different behaviour of the syn-Dechlorane Plus and anti-Dechlorane Plus isomers in the environment and different biomagnification factors in biota. This review describes the different analytical approaches applied to the determination of Dechlorane Plus and related compounds. Moreover, a summary of their levels in aquatic and terrestrial biota, as well as in humans, is presented, showing also current research results on their bioaccumulation and biomagnification potential. Finally, isomer-specific bioaccumulation of Dechlorane Plus is also discussed.

Potential chlorinated and brominated interferences on the polybrominated diphenyl ether determinations by gas chromatography-mass spectrometry

The analysis of polybrominated diphenyl ether (PBDE) congeners by GC-MS was studied in terms of potential interferences. Different MS approaches were normally used for the PBDE analyses: negative ion chemical ionization (NICI-MS) and electron ionization (EI-MS). This paper studied the presence of potential interferences in each instrumental technique approach, principally those corresponding to different chlorinated compounds (PCBs, PCNs, etc.) as well as brominated compounds (PBBs, MeO-PBDEs, TBBPA, etc.). The two ionization modes are subjected to different types of interferences. In general, EI-MS is affected by chlorinated interferences, especially PCBs. NICI-MS eliminated chlorinated interferences but presented different brominated interferences, well resolved with the EI-MS approach.

Pyrethroids: a new threat to marine mammals?

The present study constitutes the first investigation to demonstrate pyrethroid bioaccumulation in marine mammals, despite the assumption that these insecticides are converted to non-toxic metabolites by hydrolysis in mammals. Twelve pyrethroids were determined in liver samples from 23 male franciscana dolphins from Brazil. The median concentration values for total pyrethroids were 7.04 and 68.4 ng/g lw in adults and calves, respectively. Permethrin was the predominant compound, contributing for 55% of the total pyrethroids. Results showed a distinct metabolic balance of pyrethroids through dolphin life. High loads are received at the beginning of their lives and, when they reach sexual maturity, these mammals seem to degrade/metabolize pyrethroids. Maternal transfer of these compounds was also evaluated through the analysis of breast milk and placenta samples. Pyrethroids were detected in both matrices, with values between 2.53-4.77 ng/g lw and 331-1812 ng/g lw, respectively. Therefore, for the first time, a study shows mother-to-calf transfer of pyrethroids by both gestational and lactation pathways in dolphins.

Biotransformation of BDE-47 to Potentially Toxic Metabolites Is Predominantly Mediated by Human CYP2B6

Background: Previous studies have indicated that cytochrome P450s (CYPs) are involved in the metabolism of polybrominated diphenyl ether (PBDE) flame retardants in humans, resulting in the formation of hydroxylated PBDEs (OH-PBDEs) that are potentially more toxic than the parent PBDEs. However, the specific enzymes responsible for the formation of OH-PBDEs are unknown. Objectives: The purposes of this study were to characterize the in vitro metabolism of 2,2´,4,4´-tetrabromodiphenyl ether (BDE-47) by human liver microsomes (HLM) and recombinant human CYPs, and to identify the CYP(s) that are active in the oxidative metabolism of BDE-47. Methods: Recombinant human CYPs (CYP1A1, 1A2, 1B1, 2A6, 2B6, 2C8, 2C9, 2C19, 2D6, 2E1, and 3A4) were incubated with BDE-47 (20 µM), and the metabolites were measured and characterized using gas chromatography with tandem mass spectrometry (GC-MS/MS). For kinetic studies, CYP2B6 and pooled human liver microsomes (HLMs) were incubated with BDE-47 (0–60 µM). Results: CYP2B6 was the predominant CYP capable of forming six OH-BDEs, including 3-OH-BDE-47, 5-OH-BDE-47, 6-OH-BDE-47, 4-OH-BDE-42, 4´-OH-BDE-49, and a metabolite tentatively identified as 2´-OH-BDE-66. On the basis of full-scan GC-MS analysis, we hypothesized the formation of two other metabolites: di-OH-tetra-BDE and di-OH-tetrabrominated dioxin. In kinetic studies of BDE-47 metabolism by CYP2B6 and pooled HLMs, we found Km values ranging from 3.8 to 6.4 µM and 7.0 to 11.4 µM, respectively, indicating the high affinity toward the formation of OH-BDEs. Conclusion: Our findings support a predominant role of CYP2B6 in the metabolism of BDE-47 to potentially toxic metabolites, including a hypothesized di-OH-tetrabrominated dioxin metabolite. These results will assist future epidemiological studies investigating the potential of PBDEs and their metabolites to produce neurobehavioral/neurodevelopmental disorders.