Polycyclic aromatic hydrocarbons (PAHs) in human breast milk from Colombia: Spatial occurrence, sources and probabilistic risk assessment.

The diet is the main route that polycyclic aromatic hydrocarbons (PAHs) enter the body and measuring breast milk is one of the best ways to understand the maternal body burden and can be passed on to infants. In this study, it was determinate the concentrations of 23 PAHs in 60 milk samples taken from 3 cities in Colombia and to determine the potential routes of exposure and risk to human health. On average, concentration for the ∑PAHs across all locations was 186.6 ng g-1, lipid mass (LM), with city means of 260.1, 175.7, and 123.9 ng g-1 LM for Cartagena, Bogota and Medellin, respectively. Monte Carlo simulations were used to estimate the hazard quotient (HQ) and incremental lifetime cancer risk (ILCR) for infant dietary exposure to PAHs. HQs were below the safe thresholds (HQ = 1) while ILCRs were greater than the reference value equal to 10-6 (mg kg-1day-1). Dietary source assessment indicated that fish is a significant source of PAHs, with mothers that consumed fish at least once per week having ∼2.5 times greater PAH milk concentrations than other groups. While a disparity was also observed among consumers of exclusively marine (∑PAHs 198.5 ng g-1 LM) or freshwater fish (∑PAHs 85.7 ng g-1 LM). However, geographical considerations can be significant in this finding.

Remodeling of Arctic char (Salvelinus alpinus) lipidome under a stimulated scenario of Arctic warming.

Arctic warming associated with global climate change poses a significant threat to populations of wildlife in the Arctic. Since lipids play a vital role in adaptation of organisms to variations in temperature, high-resolution mass-spectrometry-based lipidomics can provide insights into adaptive responses of organisms to a warmer environment in the Arctic and help to illustrate potential novel roles of lipids in the process of thermal adaption. In this study, we studied an ecologically and economically important species-Arctic char (Salvelinus alpinus)-with a detailed multi-tissue analysis of the lipidome in response to chronic shifts in temperature using a validated lipidomics workflow. In addition, dynamic alterations in the hepatic lipidome during the time course of shifts in temperature were also characterized. Our results showed that early life stages of Arctic char were more susceptible to variations in temperature. One-year-old Arctic char responded to chronic increases in temperature with coordinated regulation of lipids, including headgroup-specific remodeling of acyl chains in glycerophospholipids (GP) and extensive alterations in composition of lipids in membranes, such as less lyso-GPs, and more ether-GPs and sphingomyelin. Glycerolipids (e.g., triacylglycerol, TG) also participated in adaptive responses of the lipidome of Arctic char. Eight-week-old Arctic char exhibited rapid adaptive alterations of the hepatic lipidome to stepwise decreases in temperature while showing blunted responses to gradual increases in temperature, implying an inability to adapt rapidly to warmer environments. Three common phosphatidylethanolamines (PEs) (PE 36:6|PE 16:1_20:5, PE 38:7|PE 16:1_22:6, and PE 40:7|PE 18:1_22:6) were finally identified as candidate lipid biomarkers for temperature shifts via machine learning approach. Overall, this work provides additional information to a better understanding of underlying regulatory mechanisms of the lipidome of Arctic organisms in the face of near-future warming.

Oxygenated and Nitrated Polycyclic Aromatic Hydrocarbons in Ambient Air-Levels, Phase Partitioning, Mass Size Distributions, and Inhalation Bioaccessibility.

Among the nitrated and oxygenated polycyclic aromatic hydrocarbons (NPAHs and OPAHs) are some of the most hazardous substances to public health, mainly because of their carcinogenicity and oxidative potential. Despite these concerns, the concentrations and fate of NPAHs and OPAHs in the atmospheric environment are largely unknown. Ambient air concentrations of 18 NPAHs, 5 quinones, and 5 other OPAHs were determined at two urban and one regional background sites in central Europe. At one of the urban sites, the total (gas and particulate) concentrations of Σ10OPAHs were 10.0 ± 9.2 ng/m3 in winter and 3.5 ± 1.6 ng/m3 in summer. The gradient to the regional background site exceeded 1 order of magnitude. Σ18NPAH concentrations were typically 1 order of magnitude lower than OPAHs. Among OPAHs, 9-fluorenone and (9,10)-anthraquinone were the most abundant species, accompanied by benzanthrone in winter. (9,10)-Anthraquinone represented two-thirds of quinones. We found that a large fraction of the target substance particulate mass was carried by submicrometer particles. The derived inhalation bioaccessibility in the PM10 size fraction is found to be ≈5% of the total ambient concentration of OPAHs and up to ≈2% for NPAHs. For 9-fluorenone and (9,10)-anthraquinone, up to 86 and 18%, respectively, were found at the rural site. Our results indicate that water solubility could function as a limiting factor for bioaccessibility of inhaled particulate NPAHs and OPAHs, without considerable effect of surfactant lipids and proteins in the lung lining fluid.

Neonicotinoid insecticides in pollen, honey and adult bees in colonies of the European honey bee (Apis mellifera L.) in Egypt.

Honeybee losses have been attributed to multiple stressors and factors including the neonicotinoid insecticides (NIs). Much of the study of hive contamination has been focused upon temperate regions such as Europe, Canada and the United States. This study looks for the first time at honey, pollen and bees collected from across the Nile Delta in Egypt in both the spring and summer planting season of 2013. There is limited information upon the frequency of use of NIs in Egypt but the ratio of positive identification and concentrations of NIs are comparable to other regions. Metabolites of NIs were also monitored but given the low detection frequency, no link between matrices was possible in the study. Using a simple hazard assessment based upon published LD50 values for individual neonicotinoids upon the foraging and brood workers it was found that there was a potential risk to brood workers if the lowest reported LD50 was compared to the sum of the maximum NI concentrations. For non-lethal exposure there was significant risk at the worst case to brood bees but actual exposure effects are dependant upon the genetics and conditions of the Egyptian honeybee subspecies that remain to be determined.

Potential health risks posed by polycyclic aromatic hydrocarbons in muscle tissues of fishes from the Athabasca and Slave Rivers, Canada.

Polycyclic aromatic hydrocarbons (PAHs) are released to the environment from oil sands operations and from natural sources in Alberta, Canada. Concentrations of 16 USEPA priority PAHs were measured in tissues of fishes collected from three locations on the Athabasca River in Alberta and two downstream locations on the Slave River in the Northwest Territories, Canada. A total of 425 individual fish were collected including 89 goldeye (Hiodon alosoides), 93 whitefish (Coregonus clupeaformis), 104 northern pike/jackfish (Esox lucius), 96 walleye (Sander vitreus) and 43 burbot/loche mariah/mariah (Lota lota). Fish were sampled during the summer and fall of 2011 and spring of 2012. Dorsal muscle of fishes from upstream reaches of the Athabasca River, close to oil sands extraction and upgrading activities, contained greater concentrations of individual PAHs than concentrations in muscle of fishes from further downstream in the Slave River. Concentrations of the sum of USEPA indicator PAHs (∑PAHs) in fishes collected in the vicinity of Fort McKay, closest to oil sands activities, varied among seasons with average concentrations ranging from 11 (burbot, summer) to 1.2 × 102 ng/g, wm (burbot, spring) with a mean of 48 ng/g, wm. Concentrations of ∑PAHs in fishes collected in the vicinity of Fort Resolution, the location most distant from oil sands activities, also varied among species and seasons, with average concentrations ranging from 4.3 (whitefish, summer) to 33 ng/g, wm (goldeye, summer) with a mean of 13 ng/g, wm. Significant differences in concentrations of ∑PAHs in muscle were observed within goldeye, jackfish, walleye and whitefish among sites. Health risks posed by PAHs to humans were assessed probabilistically using a B[a]P equivalents approach (B[a]Peq). The average lifetime risk of additional cancers for humans who consumed fish was deemed to be within an 'acceptable' range of risk (i.e., less than 10-6).

Untargeted Screening and Distribution of Organo-Bromine Compounds in Sediments of Lake Michigan.

Previously unreported natural and synthetic organo-bromine compounds (NSOBCs) have been found to contribute more than 99% of total organic bromine (TOB) in environmental matrices. We recently developed a novel untargeted method (data-independent precursor isolation and characteristic fragment, DIPIC-Frag) and identified ∼2000 NSOBCs in two sediments from Lake Michigan. In this study, this method was used to investigate the distributions of these NSOBCs in 23 surficial samples and 24 segments of a sediment core from Lake Michigan. NSOBCs were detected in all 23 surficial samples and exhibited 10- to 100-fold variations in peak abundance among locations. The pattern of distributions of NSOBCs was correlated with depth of the water column (r(2) = 0.61, p < 0.001). Hierarchical cluster analysis showed that sediments in close proximity exhibited similar profiles of NSOBCs. Distributions of NSOBCs in 24 segments of a sediment core dated from 1766 to 2008 were investigated, and samples from similar depths exhibited similar profiles of NSOBCs. NSOBCs were grouped into four clusters (soft-cluster analysis) with different temporal trends of abundances. 515 and 768 of the NSOBCs were grouped into cluster 1 and cluster 3 with increasing temporal trends, especially since 1950, indicating that abundances of these compounds might have been affected by human activities.

Untargeted Screening and Distribution of Organo-Iodine Compounds in Sediments from Lake Michigan and the Arctic Ocean.

The majority of halogenated organic compounds present in the environment remain unidentified. To address this data gap, we recently developed an untargeted method (data-independent precursor isolation and characteristic fragment; DIPIC-Frag) for identification of unknown organo-bromine compounds. In this study, the method was adapted to enable untargeted screening of natural and synthetic organo-iodine compounds (NSOICs) in sediments. A total of 4,238 NSOIC peaks were detected in sediments from Lake Michigan. Precursor ions and formulas were determined for 2,991 (71%) of the NSOIC peaks. These compounds exhibited variations in abundances (<10(3) to ∼10(7)), m/z values (206.9304-996.9474), retention times (1.0-29.7 min), and number of iodine atoms (1-4). Hierarchical cluster analysis showed that sediments in closer proximity exhibited similar profiles of NSOICs. NSOICs were screened in 10 samples of sediment from the Arctic Ocean to compare the profiles of NSOICs between freshwater and marine sediments. A total of 3,168 NSOIC peaks were detected, and profiles of NSOICs in marine sediments were clearly distinct from Lake Michigan. The coexistence of brominated and iodinated analogues indicated that some NSOICs are of natural origin. Different ratios of abundances of iodinated compounds to brominated analogues were observed and proposed as a marker to distinguish sources of NSOICs.

Products of biotransformation of polycyclic aromatic hydrocarbons in fishes of the Athabasca/Slave river system, Canada.

Concentrations of products of biotransformation of polycyclic aromatic hydrocarbons (PBPAH) were measured in bile of five fishes of nutritional, cultural and ecological relevance from the Athabasca/Slave river system. Samples were collected in Alberta and the Northwest Territories, Canada, during three seasons. As a measure of concentrations of PBPAHs to which fishes are exposed and to gain information on the nature and extent of potential exposures of people or piscivorous wildlife, concentrations of biotransformation products of two- and three-ringed, four-ringed and five-ringed PAHs were measured using synchronous fluorescence spectroscopy. Spatial and seasonal differences were observed with greater concentrations of PBPAHs in samples of bile of fish collected from Fort McKay as well as greater concentrations of PBPAHs in bile of fish collected during summer compared to those collected in other seasons. Overall, PBPAHs were greater in fishes of lower trophic levels and fishes more closely associated with sediments. In particular, goldeye (Hiodon alosoides), consistently contained greater concentrations of all the PBPAHs studied.

Untargeted Identification of Organo-Bromine Compounds in Lake Sediments by Ultrahigh-Resolution Mass Spectrometry with the Data-Independent Precursor Isolation and Characteristic Fragment Method.

While previous studies have found that unknown natural and synthetic organo-bromine compounds (NSOBCs) contributed more than 99% of the total organic bromine (Br) in the environment, there was no efficient method for untargeted screening to identify NSOBCs in environmental matrixes. A novel untargeted method for identifying NSOBCs, based on ultrahigh-resolution mass spectrometry (UHRMS) with the Q Exactive instrument was developed. This method included a data-independent precursor isolation and characteristic fragment (DIPIC-Frag) procedure to identify NSOBCs. A total of 180 successive 5-m/z-wide windows were used to isolate precursor ions. This resulted in a sufficient dynamic range and specificity to identify peaks of Br fragment ions for analysis. A total of 2520 peaks of NSOBC compounds containing Br were observed in sediments from Lake Michigan, United States. A new chemometric strategy which combined chromatographic profiles, isotopic peaks, precursor isolation window information, and intensities was used to identify precursor ions and chemical formulas for detecting NSOBCs. Precursor ions for 2163 of the 2520 NSOBCs peaks (86%) were identified, and chemical formulas for 2071 NSOBCs peaks (82%) were determined. After exclusion of isotopic peaks, 1593 unique NSOBCs were identified and chemical formulas derived for each. Most of the compounds identified had not been reported previously and had intensities which were 100- to 1000-fold greater than the congeners of polybrominated diphenyl ethers (PBDEs). In extracts of sediments, these compounds exhibited variations in intensities (<10(3) to ∼10(8)), m/z values (170.9438-997.5217), retention times on a C18 column (1.0-29.3 min), and the number of Br atoms (1-8). Generally, compounds with greater m/z values had longer retention times and greater numbers of Br atoms. Three compounds were used in a proof-of-concept experiment to demonstrate that structures of some of the screened NSOBCs could be further predicted by combining searching of database libraries and high-resolution MS(2) spectra.

Detection, identification, and quantification of hydroxylated bis(2-ethylhexyl)-tetrabromophthalate isomers in house dust.

Ultra-High Resolution LC/mass spectrometry (LC-UHRMS; Thermo Fisher Q-Exactive) was used to identify two novel isomers of hydroxylated bis(2-ethylhexyl)-tetrabromophthalate (OH-TBPH) which were unexpectedly observed in a commercial standard of TBPH. By combining ultra-high resolution (UHR) mass spectra (MS(1)), mass errors to theoretical [TBPH-Br+O](-) were 2.1 and 1.0 ppm for the two isomers, UHR-MS(2) spectra and NMR analysis; the structures of the two compounds were identified as hydroxylated TBPH with a hydroxyl group on the aromatic ring. Relatively great proportions of the two isomers of OH-TBPH were detected in two technical products, Firemaster 550 (FM-550; 0.1% and 6.2%, respectively) and Firemaster BZ 54 (BZ-54; 0.1% and 7.9%), compared to a commercial standard (0.4% and 0.9%). To simultaneously analyze OH-TBPH isomers and TBPH in samples of dust, a method based on LC-UHRMS was developed to quantify the two compounds, using negative and positive ion modes, respectively. The instrumental limit of detection for TBPH was 0.01 µg/L, which was 200-300 times better than traditional methods (2.5 µg/L) based on gas chromatography-mass spectrometry. The analytical method combined with a Florisil cleanup was successfully applied to analyze TBPH and OH-TBPH in 23 indoor dust samples from Saskatoon, Saskatchewan, Canada. Two OH-TBPH isomers, OH-TBPH1 and OH-TBPH2, were detected in 52% and 91% of dust samples, respectively. Concentrations of OH-TBPH2 (0.35 ± 1.0 ng/g) were 10-fold greater than those of OH-TBPH1 (0.04 ± 0.88 ng/g) in dust, which was similar to profiles in FM-550 and BZ-54. TBPH was also detected in 100% of dust samples with a mean concentration of 733 ± 0.87 ng/g. A significant (p < 0.001) log-linear relationship was observed between TBPH and OH-TBPH isomers, further supporting the hypothesis of a common source of emission. Relatively small proportions of OH-TBPH isomers were detected in dust (0.01% ± 0.67 OH-TBPH1 and 0.1% ± 0.60 OH-TBPH2), which were significantly less than those in technical products (p < 0.001). This result indicated different environmental behaviors of OH-TBPH and TBPH. Detection of isomers of OH-TBPH is important, since compounds with phenolic groups have often shown relatively greater toxicities than nonhydroxylated analogues. Further study is warranted to clarify the environmental behaviors and potential toxicities of OH-TBPH isomers.

Organophosphorus insecticides in honey, pollen and bees (Apis mellifera L.) and their potential hazard to bee colonies in Egypt.

There is no clear single factor to date that explains colony loss in bees, but one factor proposed is the wide-spread application of agrochemicals. Concentrations of 14 organophosphorous insecticides (OPs) in honey bees (Apis mellifera) and hive matrices (honey and pollen) were measured to assess their hazard to honey bees. Samples were collected during spring and summer of 2013, from 5 provinces in the middle delta of Egypt. LC/MS-MS was used to identify and quantify individual OPs by use of a modified Quick Easy Cheap Effective Rugged Safe (QuEChERS) method. Pesticides were detected more frequently in samples collected during summer. Pollen contained the greatest concentrations of OPs. Profenofos, chlorpyrifos, malation and diazinon were the most frequently detected OPs. In contrast, ethoprop, phorate, coumaphos and chlorpyrifos-oxon were not detected. A toxic units approach, with lethality as the endpoint was used in an additive model to assess the cumulative potential for adverse effects posed by OPs. Hazard quotients (HQs) in honey and pollen ranged from 0.01-0.05 during spring and from 0.02-0.08 during summer, respectively. HQs based on lethality due to direct exposure of adult worker bees to OPs during spring and summer ranged from 0.04 to 0.1 for best and worst case respectively. It is concluded that direct exposure and/or dietary exposure to OPs in honey and pollen pose little threat due to lethality of bees in Egypt.

Accumulation of perfluoroalkyl compounds in tibetan mountain snow: temporal patterns from 1980 to 2010.

The use of snow and ice cores as recorders of environmental contamination is particularly relevant for per- and polyfluoroalky substances (PFASs) given their production history, differing source regions and varied mechanisms driving their global distribution. In a unique study perfluoroalkyl acids (PFAAs) were analyzed in dated snow-cores obtained from high mountain glaciers on the Tibetan Plateau (TP). One snow core was obtained from the Mt Muztagata glacier (accumulation period of 1980-1999), located in western Tibet and a second core from Mt. Zuoqiupo (accumulation period: 1996-2007) located in southeastern Tibet, with fresh surface snow collected near Lake Namco in 2010 (southern Tibet). The higher concentrations of ∑PFAAs were observed in the older Mt Muztagata core and dominated by perfluorooctanesulfonic acid (PFOS) (61.4-346 pg/L) and perfluorooctanoic acid (PFOA) (40.8-243 pg/L), whereas in the Mt Zuoqiupu core the concentrations were lower (e.g., PFOA: 37.8-183 pg/L) with PFOS below detection limits. These differences in PFAA concentrations and composition profile likely reflect the upwind sources affecting the respective sites (e.g., European/central Asian sources for Mt Muztagata and India sources for Mt Zuoqiupu). Perfluorobutanoic acid (PFBA) dominated the recent surface snowpack of Lake Namco which is mainly associated with India sources where the shorter chain volatile PFASs precursors predominate. The use of snow cores in different parts of Tibet provides useful recorders to examine the influence of different PFASs source regions and reflect changing PFAS production/use in the Northern Hemisphere.

Polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) in human breast milk from Colombia: A probabilistic risk assessment approach.

Polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs) are ubiquitous environmental contaminants. They were produced in relatively large volumes in the last century and are now subject to long-term monitoring and regulated under the United Nations Stockholm Convention (SC) on persistent organic pollutants (POPs). Though restricted, human exposure is still a concern and in some regions of the globe the information on the health risk is limited. Sixty breast milk samples from nursing mothers were collected between 2014 and 2015, residing in Bogota, Cartagena, and Medellin, which are industrialized cities in Colombia. This is the first comprehensive study to determine the concentrations in breast milk of PBDEs (n = 7), PCBs (n = 29), and OCPs (n = 28) in Colombia. The detection frequency of POPs, including BDE-47, CB-138, CB-153, CB-156, and CB-180, as well as several OCPs such as chloroneb, aldrins, HCHs, DDTs, and heptachlor, was found to be 100% in all samples tested. The mean concentrations of the analyzed legacy POPs were ∑3DDTs (423 ng/g lw) > chloroneb (50.1 ng/g lw) > ∑2permetrins (17.5 ng/g lw) > ∑2aldrins (16.7 ng/g lw) > 29 PCBs (15.04 ng/g lw) > ∑2chlordanes (CHLs) (11.2 ng/g lw) ≈ ∑3endosulfans (11.1 ng/g lw) > ∑2heptachlors (2.43 ng/g lw) > 7PBDEs (2.1 ng/g lw) > ∑4HCHs (0.58 ng/g lw). The results of this study suggest that the concentrations of DDTs were present in breast milk samples from Colombia at levels comparable to those found in previous studies conducted in other countries such as Brazil, Uruguay, Chile, and various Asian countries. The concentrations of PBDE and PCB congeners, as well as many pesticides, were found to be significantly correlated with each other. This suggests that these substances may have similar sources of exposure. The strength of the pair correlation among concentrations of POPs was assessed using Spearman's correlation coefficients, which varied from r = 0.62 for the association between BDE-47 and CB-153, to a high correlation of 0.99 for the correlation between γ-Chlordane and heptachlor. This suggests that these POPs may share similar sources, such as diet. An exposure assessment model obtained by Monte Carlo simulation showed that infants were exposed to low concentrations of POPs with exception of p,p'-DDE and Aldrin, in which 25th, 50th and 95th percentiles were greater than the threshold reference values of non-carcinogenic effects suggested by US-EPA regulations while the 90th percentile of pg TEQ/Kg-bw/day for dl-PCBs was above of the tolerable daily intake (TDI) proposed by the World Health Organization (WHO). Therefore, the health risk of infants exposed to OCPs and dl-PCBs should be exanimated continually through biomonitoring programs in the Colombian population.

LC-HRMS based method for suspect/non-targeted screening for biomarkers of chemical exposure in human urine.

Every day we are exposed to a cocktail of anthropogenic compounds many of which are biologically active and capable of inducing negative effects. The simplest way to monitor contaminants in a population is via human biomonitoring (HBM), however conventional targeted approaches require foreknowledge of chemicals of concern, often have compound specific extractions and provide information only for those compounds. This study developed an extraction process for human biomarkers of interest (BoE) in urine that is less compound specific. Combining this with an ultra-high resolution mass spectrometer capable of operating in full scan, and a suspect and non-targeted analysis (SS/NTA) approach, this method provides a more holistic characterization of human exposure. Sample preparation development was based on enzymatically hydrolysed urine spiked with 34 native standards and extracted by solid-phase extraction (SPE). HRMS data was processed by MzMine2 and 80% of standards were identified in the final data matrix using typical NTA data processing procedures.

Application of 96-well plate SPE method for analysis of persistent organic pollutants in low volume blood serum samples.

Though many persistent organic pollutants (POPs) are closely regulated the human population is still exposed to these ubiquitous chemicals from the environment and diet. Safe management and human biomonitoring of POPs is necessary to understand the risk of exposure. Within human biomonitoring the mass of sample is often limited, therefore robust methods using smaller sample amounts are necessary. This study developed a 96-well plate solid phase extraction (SPE) method for determination of selected POPs: polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD) and non-persistent novel flame retardants (NFRs) in low volume blood serum. Non-destructive clean-up coupling Oasis HLB extraction plate with Phree phospholipid removal plate was employed. Extraction efficiency was determined at low and high concentrations in certified reference materials NIST SRM 1957 and 1958, respectively. Target compounds deviated from certified values on average by 15% and 21% for SRM 1957 and SRM 1958, respectively. Observed limit of detections (LODs) ranged from 0.36 pg/mL (PCB 180) to 66.07 pg/mL (δ-HCH). The applicability for real samples is demonstrated on 48 samples from pregnant women enrolled in the pilot phase of the CELSPAC: TNG study. In total, 30 target compounds were detected in at least one sample. The method developed here provides a fast and reliable analysis of human blood serum with possibility to introduce automation for the sample preparation procedure.

Suspect and non-targeted screening-based human biomonitoring identified 74 biomarkers of exposure in urine of Slovenian children.

Human exposure to organic contaminants is widespread. Many of these contaminants show adverse health effects on human population. Human biomonitoring (HBM) follows the levels and the distribution of biomarkers of exposure (BoE), but it is usually done in a targeted manner. Suspect and non-targeted screening (SS/NTS) tend to find BoE in an agnostic way, without preselection of compounds, and include finding evidence of exposure to predicted, unpredicted known and unknown chemicals. This study describes the application of high-resolution mass spectrometry (HRMS)-based SS/NTS workflow for revealing organic contaminants in urine of a cohort of 200 children from Slovenia, aged 6-9 years. The children originated from two regions, urban and rural, and the latter were sampled in two time periods, summer and winter. We tentatively identified 74 BoE at the confidence levels of 2 and 3. These BoE belong to several classes of pharmaceuticals, personal care products, plasticizers and plastic related products, volatile organic compounds, nicotine, caffeine and pesticides. The risk of three pesticides, atrazine, amitraz and diazinon is of particular concern since their use was limited in the EU. Among BoE we tentatively identified compounds that have not yet been monitored in HBM schemes and demonstrate limited exposure data, such as bisphenol G, polyethylene glycols and their ethers. Furthermore, 7 compounds with unknown use and sources of exposure were tentatively identified, either indicating the entry of new chemicals into the market, or their metabolites and transformation products. Interestingly, several BoE showed location and time dependency. Globally, this study presents high-throughput approach to SS/NTS for HBM. The results shed a light on the exposure of Slovenian children and raise questions on potential adverse health effects of such mixtures on this vulnerable population.

Open, High-Resolution EI+ Spectral Library of Anthropogenic Compounds.

To address the lack of high-resolution electron ionisation mass spectral libraries (HR-[EI+]-MS) for environmental chemicals, a retention-indexed HR-[EI+]-MS library has been constructed following analysis of authentic compounds via GC-Orbitrap MS. The library is freely provided alongside a compound database of predicted physicochemical properties. Currently, the library contains over 350 compounds from 56 compound classes and includes a range of legacy and emerging contaminants. The RECETOX Exposome HR-[EI+]-MS library expands the number of freely available resources for use in full-scan chemical exposure studies and is available at: https://doi.org/10.5281/zenodo.4471217.

Targeted and suspect screening of plasticizers in house dust to assess cumulative human exposure risk.

Indoor dust is an important exposure route to anthropogenic chemicals used in consumer products. Plasticizers are common product additives and can easily leach out of the product and partition to dust. Investigations of plasticizers typically focus on a subset of phthalate esters (PEs), but there are many more PEs in use, and alternative plasticizers (APs) are seeing greater use after recognition of adverse health effects of PEs. In this study we use full scan high resolution mass spectrometry for targeted and suspect screening of PEs and APs in house dust and to assess the potential risk of human exposure. House dust samples from Eastern Slovakia were investigated and concentrations of ∑12PEs and ∑5APs ranged 12-2765 µg/g and 45-13,260 µg/g, respectively. APs were at similar levels to PEs, indicating common usage of these compounds in products in homes. Evaluation of individual compound toxicity combined with human intake via dust ingestion suggested PEs are of lower priority compared to semivolatile organic compounds such as polychlorinated biphenyls due to their lower toxicity. However, cumulative risk assessment (CRA) is a more appropriate evaluation of risk, considering the presences of many PEs in dust and their similar toxic mode of action. CRA based on median toxicity reference values (TRVs) suggested acceptable risks for dust ingestion, however, the wide range of literature-derived TRVs is a large uncertainty, especially for the APs. Use of newer TRVs suggest risk from dust ingestion alone, i.e. not even considering diet, inhalation, and dermal contact. Additionally, screening of full-scan instrumental spectra identified a further 40 suspect PE compounds, suggesting the CRA based on the 12 target PEs underestimates the risk.

Molecular mechanisms of zooplanktonic toxicity in the okadaic acid-producing dinoflagellate Prorocentrum lima.

Prorocentrum lima is a dinoflagellate that forms hazardous blooms and produces okadaic acid (OA), leading to adverse environmental consequences associated with the declines of zooplankton populations. However, little is known about the toxic effects and molecular mechanisms of P. lima or OA on zooplankton. Here, their toxic effects were investigated using the brine shrimp Artemia salina. Acute exposure of A. salina to P. lima resulted in lethality at concentrations 100-fold lower than densities observed during blooms. The first comprehensive results from global transcriptomic and metabolomic analyses in A. salina showed up-regulated mRNA expression of antioxidant enzymes and reduced non-enzyme antioxidants, indicating general detoxification responses to oxidative stress after exposure to P. lima. The significantly up-regulated mRNA expression of proteasome, spliceosome, and ribosome, as well as the increased fatty acid oxidation and oxidative phosphorylation suggested the proteolysis of damaged proteins and induction of energy expenditure. Exposure to OA increased catabolism of chitin, which may further disrupt the molting and reproduction activities of A. salina. Our data shed new insights on the molecular responses and toxicity mechanisms of A. salina to P. lima or OA. The simple zooplankton model integrated with omic methods provides a sensitive assessment approach for studying hazardous algae.

Concentrations of Metals in Fishes from the Athabasca and Slave Rivers of Northern Canada.

There is growing concern about possible effects of exploitation of the Alberta Oil Sands on the ambient environment, including possible effects on populations of fishes in the Athabasca River and farther downstream in Lake Athabasca and the Slave River. In the present study, concentrations of metals in dorsal muscle tissue of 5 fish species-goldeye, northern pike, walleye, whitefish, and burbot-from the Slave, Peace, and Athabasca Rivers were quantified. A suite of 25 metals including As, Hg, Se, Tl, and V was analyzed. Most metals exhibited no significant variations in concentration among locations. Concentrations of 5 metals, As, Hg, Se, Tl, and V, revealed significant variations among locations and were of sufficient magnitude to be of interest. Concentrations of Hg did not vary significantly among locations; however, because it was detected at concentrations of concern and the use of the selected fishes was a local source of food for humans and pets, it was of interest. Concentrations of As, Se, Tl, and V in dorsal muscle of certain fishes in the farthest downstream sites on the Slave River were greater than those in the same tissues and species in the farther upstream sites on the Peace and Athabasca Rivers. This phenomenon was most prevalent with Tl and to a lesser extent with As and Se. Nevertheless, concentrations were not of concern for the health of human consumers. Although metals did not appear to be increased in fish in the Alberta Oil Sands region in the present study, further research is needed to understand the potential impacts. Environ Toxicol Chem 2020;39:2180-2195. © 2020 SETAC.