Polychlorinated alkanes in paired blood serum and breast milk in a Swedish cohort study: Matrix dependent partitioning differences compared to legacy POPs.

BACKGROUND: Polychlorinated alkanes (PCAs) constitute a large group of individual congeners originating from commercial chlorinated paraffin (CP) products with carbon chain lengths of PCAs-C10-13, PCAs-C14-17, and PCAs-C18-32, occasionally containing PCAs-C6-9 impurities. The extensive use of CPs has led to global environmental pollution of PCAs. This study aimed to quantify PCAs in paired serum and breast milk of lactating Swedish mothers, exploring their concentration relationship. METHODS: Twenty-five paired samples of mothers' blood serum and breast milk were analysed and concentrations were determined for PCAs C6-32 and compared to 4,4'-DDE, the PCB congener 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153), and hexachlorobenzene (HCB). RESULTS: The median concentrations of PCAs-C6-9, PCAs-C10-13, PCAs-C14-17, PCAs-C18-32 and ΣPCAs in serum were 14, 790, 520, 16 and 1350 ng/g lipid weight (lw), respectively, and in breast milk 0.84, 36, 63, 6.0 and 107 ng/g lw. Levels of 4,4'-DDE, CB-153 and HCB were comparable in the two matrices, serum and breast milk at 17, 12 and 4.9 ng/g lw. The results show significant differences of PCAs-C10-13 and PCAs-C14-17 in breast milk with 22- and 6.2-times lower lw-based concentrations than those measured in serum. On wet weight the differences serum/breast milk ratios of PCAs-C6-9, PCAs-C10-13, PCAs-C14-17, PCAs-C18-32 and ΣPCAs were 1.7, 3.2, 1.0, 0.4 and 1.6, respectively, while the ratio for 4,4'-DDE, CB-153 and HCB were each close to 0.1. CONCLUSION: Swedish lactating mothers had high serum concentrations of PCAs-C10-13 and PCAs-C14-17, with the ΣPCAs median serum concentration of 1350 ng/g lw. The breast milk concentration, although considerably lower at 107 ng/g lw, still surpassed those of 4,4'-DDE, CB-153 and HCB, suggesting an exposure risk of infants to PCAs. The variation in blood and breast milk accumulation between PCAs and studied legacy POPs, is rarely discussed but warrants further studies on partitioning properties as well as associated toxicological implications.

Legacy persistent organic pollutants (POPs) in eggs of night herons and poultries from the upper Yangtze Basin, Southwest China.

Black-crowned night heron (Nycticorax nycticorax) eggs have been identified as useful indicators for biomonitoring the environmental pollution in China. In this study, we investigated thirty eggs of black-crowned night heron collected from the upper Yangtze River (Changjiang) Basin, Southwest China, for the occurrence of legacy persistent organic pollutants (POPs), including polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs). Our results showed a general presence of POPs in night heron eggs with OCPs being the dominant contaminants, having a geometric mean concentration of 22.2 ng g-1 wet weight (ww), followed by PCBs (1.36 ng g-1 ww), PBDEs (0.215 ng g-1 ww), and PCDD/Fs (23.0 pg g-1 ww). The concentration levels were found to be significantly higher in night heron eggs than in poultry eggs by one or two magnitude orders. Among OCP congeners, p,p'-DDE was found to be predominant in night heron eggs, with a geometric mean concentration of 15.1 ng g-1 ww. Furthermore, species-specific congener patterns in eggs suggested similar or different sources for different POPs, possibly associated with contaminated soil and parental dietary sources. Additionally, estimated daily intakes (EDIs) were used to evaluate non-carcinogenic and carcinogenic risk associated with consumption of bird eggs. Our results revealed non-negligible non-cancer and cancer risk for humans who consume wild bird eggs as a regular diet instead of poultry eggs.

Detecting long temporal trends of photosystem II herbicides (PSII) in the Great Barrier Reef lagoon.

The Marine Monitoring Program (MMP) was established in 2005 to monitor the inshore health of the Great Barrier Reef (GBR) and evaluate progress towards water quality objectives in Reef Water Quality Improvement Plans. The MMP provides information on the magnitude and spatial extent of pesticide contamination, reports on temporal variability, and provides a risk assessment for the biota in the GBR lagoon. However, long-term trends in pesticide contamination of inshore marine waters over the entire monitoring period (2005-2018) have not been assessed. We used up to 14 years of monitoring data for five PSII herbicides (ametryn, atrazine, diuron, tebuthiuron, and hexazinone) to conduct temporal trend analyses at 11 inshore monitoring sites. The trend analyses suggested increasing significant trends (p < 0.05) for the five PSII herbicides concentrations at several monitoring sites. Power analysis indicated that monitoring sites with over 10 years of monitoring data had convincing results with 80% power.

Correlating seasonal changes of naturally produced brominated compounds to biomarkers in perch from the Baltic Sea.

Hydroxylated polybrominated diphenyl ethers (OH-PBDEs), naturally produced by algae and cyanobacteria in the Baltic Sea, are potent disrupters of energy metabolism as well as endocrine disruptors and neurotoxins. In this study, European perch (Perca fluviatilis) from the Baltic Sea were sampled from May until October. OH-PBDEs and ten biomarkers were measured in each individual (n = 84 over 18 sampling time points) to study potential correlations between exposure to OH-PBDEs and changes in biomarkers. Several biomarkers showed significant non-linear seasonal variation. In the perch, ethoxyresorufin-O-deethylase (EROD) activity, plasma lactate concentration, and plasma glucose concentration showed a significant positive log-linear correlation with OH-PBDEs, whereas lipid percentage and liver somatic index showed a significant negative log-linear correlation with OH-PBDEs. These results strengthen the concern that OH-PBDEs could cause negative health effects for fish in the Baltic Sea.

Major lead exposure from hunting ammunition in eagles from Sweden.

Exposure to lead (Pb) from ammunition in scavenging and raptorial birds has achieved worldwide recognition based on incidences of lethal poisoning, but exposure implies also sublethal levels with potential harmful effects. Background and elevated Pb levels in liver from 116 golden eagles (GE, Aquila chrysaetos) and 200 white-tailed sea eagles (WTSE, Haliaeetus albicilla) from Sweden 2003-2011 are here examined, with supporting data from a previous WTSE report and eagle owl (EO, Bubu bubo) report. GE and WTSE display seasonal patterns, with no Pb level exceeding a generally accepted threshold for subclinical effects during summer but strongly elevated levels from October. Fledged juveniles show significantly lower levels than all other age classes, but reach levels found in older birds in autumn after the start of hunting seasons. Pb levels in EO (non-scavenger) show no seasonal changes and indicate no influence from ammunition, and are close to levels observed in juvenile eagles before October. In all, 15% WTSE and 7% GE were lethally poisoned. In areas with high-exposure to hunting ammunition, 24% of WTSE showed lethal Pb levels, compared to 7% in both eagle species from low-exposure areas. Lethal poisoning of WTSE remained as frequent after (15%) as before (13%) a partial ban on use of Pb-based shotgun ammunition over shallow waters (2002). Pb levels increased significantly in WTSE 1981-2011, in contrast to other biota from the same period. A significant decrease of Pb in WTSE liver occurred below a threshold at 0.25 µg/g (dry weight), exceeded by 81% of the birds. Trend patterns in Pb isotope ratios lend further support to this estimated cut-off level for environmental background concentrations. Pb from spent ammunition affects a range of scavenging and predatory species. A shift to Pb-free ammunition to save wildlife from unnecessary harm is an important environmental and ethical issue.

Are temporal trends of some persistent organochlorine and organobromine compounds in Swedish breast milk slowing down?

We investigated body burdens of persistent organic pollutants (POPs) in Swedish first-time mothers by measurements in breast milk, and followed up the temporal trends between 1996 and 2017. POPs were analysed in individual samples (n = 539) from participants from Uppsala county, Sweden. This made it possible to adjust temporal trends for age of the mother, pre-pregnancy BMI, weight gain during pregnancy, weight loss after delivery, and education, the main determinants for POP body burdens, apart from sampling year. We also compared observed body burdens with the body burdens determined to be safe from a health perspective in the risk assessment of dioxin-like polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), published by the European Food Safety Authority (EFSA). Declining temporal trends in breast milk of on average -4 to 14% per year were observed 1996-2017 for PCBs, PCDD/Fs, chlorinated pesticides, and brominated flame retardants, except for the polybrominated diphenyl ethers (PBDEs) BDE-153 and BDE-209. The toxic equivalents (TEQs) for PCDD declined faster than PCDF TEQs, -6.6% compared to -3.5% per year. For CB-169, CB-180, PCDDs, PCDFs, Total TEQ, and hexachlorobenzene (HCB), a change point year (CP) was observed around 2008-2009 and after that, the decline in levels has slowed down. If breast milk levels follows the exponential declining trend of total TEQ estimated for the entire period (-5.7% per year), 97.5% of first time mothers from the Uppsala area will have body burdens below the estimated safe level in year 2022. If instead it follows the estimated % decline after the CP in 2008 (-1.6% per year), it will take until 2045 before 97.5% is below the estimated safe level. It is important to proceed with the monitoring of POPs in breast milk from Swedish mothers in order to further observe if the levels are stabilizing or continue to decline.

Per- and polyfluoroalkyl substances (PFASs) in Swedish household dust and exposure of pet cats.

Per- and polyfluoroalkyl substances (PFASs) are used in a wide range of products and have been found ubiquitously in our indoor environment, and there is evidence that exposure to PFAS can lead to adverse endocrine effects, such as thyroid hormone disruption. Pet cats have a high dust intake due to their grooming behavior and have been shown to be a suitable sentinel species for assessment of toddler's exposure. Here we used paired household dust (n=46) and cat serum (n=27) samples to establish whether dust is a relevant exposure pathway to PFASs. An analytical method for PFAS analysis was optimized using a low volume of cat serum samples, combining solid-phase extraction and online sample cleanup. Dust was extracted with methanol by sonication and cleaned up by addition of active carbon. In total, 27 PFASs were analyzed by liquid chromatography/mass spectrometry analysis. The correlation between PFAS levels in dust and serum, serum lipids and thyroid hormone levels, and PFAS levels in dust between different rooms were statistically evaluated. PFOS and PFDA could be quantified in all cat serum samples (median 2300 pg/mL and 430 pg/mL, respectively), followed by PFOA (median 1100 pg/mL), quantified in 96% of the samples. The levels of 6:2 and 8:2 diPAPs were determined in 65% and 92% of the serum samples, respectively, and were an order of magnitude lower (1.4-160 pg/mL). Household dust on the other hand was dominated by 6:2 and 8:2 diPAPs, with a median of 65 ng/g dust and 49 ng/g dust, respectively. PFOS (median 13 ng/g dust) and PFOA (median 9 ng/g dust) were quantified in 93% of the dust samples. Only eight PFASs were detected (>LOD) in at least 50% of the samples of both matrices and could be paired. Significant correlations between cat serum and dust were found for PFOA (rS=0.32, p<0.049) and PFUnDA (rS=0.55, p<0.001). Significant positive correlations were found between serum total thyroxine (rS=0.11, p<0.05) and PFNA and between serum cholesterol and PFHpA (rS=0.46, p<0.01), PFUnDA (rS=0.40, p<0.05), PFDoDA (rS=0.44, p<0.01), and sum PFAS (rS=0.48, p<0.01). In conclusion, this study confirmed that dust is a relevant exposure pathway for the ingestion of some PFASs for cats, and the serum levels of PFASs could be of relevance for the cat's health.

Ecological changes as a plausible explanation for differences in uptake of contaminants between European perch and eelpout in a coastal area of the Baltic Sea.

Unexpected increasing trends in the concentration of contaminants in European perch (Perca fluviatilis) and in activity of ethoxyresorufin-O-deethylase (EROD) in European perch and eelpout (Zoarces viviparus) have been observed at a Swedish coastal reference site. This study uses data from different sources to investigate plausible explanations. The results showed that a change in diet and an improved overall condition coincide with an increase in mercury in European perch. Furthermore, an increase in several organic contaminants in European perch coincided with the introduction of an invasive deep-burrowing polychaete, which likely contributed to the release of contaminants through bioturbation. The increase in EROD-activity in both species seems to be related to contaminants that reach the fish through the water rather than the diet. The results show that for contaminants that are taken up via the diet, trends in contamination can be opposite for different species of fish in the same area.

Presence and Health Risks of Obsolete and Emerging Pesticides in Paddy Rice and Soil from Thailand and China.

Organochlorine (OCPs) and organophosphorus pesticides (OPPs) have been intensively applied in rice paddy field farming to control pest infestation and increase the yield. In this study, we investigated the presence of organochlorine and organophosphorus pesticides in paddy rice and soil from rice plantations in Thailand and China. According to concentration and distribution of OCPs, the most abundant OCPs residues in rice and soil from Thailand and China were dichlorodiphenyltrichloroethane and hexachlorocyclohexanes. The OPPs of methidathion, carbophenothion, chlorpyrifos, and diazinon were common to Thailand and China in both types of samples. The detection frequency of multiple types of these pesticides was greater than 50% of total samples. The relative concentration of some OPPs residues in rice and soil from Thailand and China were significantly different from each other (p < 0.0083), whereas, no significant difference was observed for the relative concentration of OCPs residues in rice and soil from both countries, except for HCHs (p < 0.05). Bioaccumulation factors of OCPs between rice and soil samples indicated that OCPs and OPPs in soil could accumulate in rice. The carcinogenic and non- carcinogenic risks of OCPs and OPPs seem to be in the safe range as recommended by the European Union.

Temporal trends of suspect- and target-per/polyfluoroalkyl substances (PFAS), extractable organic fluorine (EOF) and total fluorine (TF) in pooled serum from first-time mothers in Uppsala, Sweden, 1996-2017.

A combined method for quantitative analysis, along with suspect and non-target screening of per- and polyfluoroalkyl substances (PFAS) was developed using ultra-high pressure liquid chromatography-ultra-high resolution (Orbitrap) mass spectrometry. The method was applied together with measurements of total- and extractable organofluorine (TF and EOF, respectively), to pooled serum samples from 1996-2017 from first-time mothers living in the county of Uppsala, Sweden, some of which (i.e. 148 of 472 women sampled 1996-2012) were exposed to drinking water contaminated with perfluorohexane sulfonate (PFHxS) and other PFAS until mid-2012. Declining trends were observed for all target PFAS as well as TF, with homologue-dependent differences in year of onset of decline. Only 33% of samples displayed detectable EOF, and amongst these samples the percentage of EOF explained by target PFAS declined significantly (-3.5% per year) over the entire study period. This finding corroborates prior observations in Germany after the year 2000, and may reflect increasing exposure to novel PFAS which have not yet been identified. Suspect screening revealed the presence of perfluoro-4-ethylcyclohexanesulfonate (PFECHS), which displayed declining trends since the year 2000. Non-target time trend screening revealed 3 unidentified features with time trends matching PFHxS. These features require further investigation, but may represent contaminants which co-occurred with PFHxS in the contaminated drinking water.

Chlorinated Paraffins in Human Milk from Urban Sites in China, Sweden, and Norway.

Short-, medium-, and long-chain chlorinated paraffins (SCCPs, MCCPs, and LCCPs) were analyzed in human milk from the Yangtze River Delta (YRD) and Scandinavia. Individual samples were collected from Shanghai, Jiaxing, and Shaoxing (China), Stockholm (Sweden), and Bodø (Norway) between 2010 and 2016. Mean concentrations (range) of SCCPs, MCCPs, and LCCPs in samples from the YRD were 124 [

Temporal Trends (1981-2013) of Per- and Polyfluoroalkyl Substances and Total Fluorine in Baltic cod (Gadus morhua).

Temporal trends from 1981 to 2013 of 28 per- and polyfluoroalkyl substances (PFASs) were investigated in liver tissue of cod (Gadus morhua) sampled near southeast Gotland, in the Baltic Sea. A total of 10 PFASs were detected, with ∑28 PFAS geometric mean concentrations ranging from 6.03 to 23.9 ng/g ww. Perfluorooctane sulfonate (PFOS) was the predominant PFAS, which increased at a rate of 3.4% per year. Most long-chain perfluoroalkyl carboxylic acids increased at rates of 3.9 to 7.3% per year except for perfluorooctanoate (PFOA), which did not change significantly over time. The perfluoroalkyl acid precursors perfluorooctane sulfonamide (FOSA) and 6:2 fluorotelomer sulfonic acid were detected, of which the former (FOSA) declined at a rate of -4.4% per year, possibly reflecting its phase-out starting in 2000. An alternate time trend analysis from 2000 to 2013 produced slightly different results, with most compounds increasing at slower rates compared to the entire study period. An exception was perfluorohexane sulfonate (PFHxS), increasing at a faster rate of 3.7% measured from 2000 on, compared to the 3.0% per year measured starting from 1981. Analysis of the total fluorine content of the samples revealed large amounts of unidentified fluorine; however, its composition (organic or inorganic) remains unclear. Significant negative correlations were found between concentrations of individual PFASs (with the exception of PFOS) and liver somatic index. In addition, body length was negatively correlated with PFOA and perfluorononanoate, but positively correlated with perfluorododecanoate (PFDoDA) and FOSA. Additional studies on endocrine, immunological, and metabolic effects of PFAS in marine fish are essential to assess the environmental risk of these substances. Environ Toxicol Chem 2020;39:300-309. © 2019 SETAC.

Temporal Changes in Concentrations of Lead and Other Trace Metals in Free-Ranging Eurasian Eagle Owls Bubo bubo in Sweden.

Patterns of lead and other trace metals were examined in 122 Eurasian eagle owls Bubo bubo found dead in Sweden in the period 1978-2013. Environmental lead (Pb) has decreased over recent decades from reduced anthropogenic emissions but mortality by Pb poisoning is still frequently reported for avian raptors and scavengers exposed to Pb ammunition. One objective here was to determine if Pb concentrations in a nocturnal non-scavenging raptor follow the general decline observed in other biota. Pb concentration in owl liver was significantly correlated with body weight, sex, latitude, longitude and season. Pb showed a significant decreasing trend towards north and west. Starved birds had significantly higher concentrations. Total Pb concentrations in liver averaged 0.179 µg g-1 dry weight (median 0.103) and decreased by 5.6% per year 1978-2013, or 5.3% after adjustment for confounding factors, similar to trends in other species. Among 14 other trace elements only antimony and arsenic showed decreasing trends. Lead isotope ratios 206Pb/207Pb and 208Pb/207Pb increased from 1.138 and 2.408 in 1978-1985 to 1.170 and 2.435 in 2010-2013, respectively, demonstrating that the decreasing Pb concentration in eagle owl is related to the phase-out of leaded gasoline in Europe, where Pb additives had much lower isotope ratios than natural lead in Swedish soils. Only one incidence of suspected Pb poisoning (40.7 µg g-1 in liver) was observed indicating that poisoning from ingestion of metallic lead is rare (< 1%) in eagle owl in Sweden, in contrast to what has been reported for eagles.

Organophosphate flame retardants in heron eggs from upper Yangtze River basin, southwest China.

The egg samples of four heron species, including black-crowned night heron (Nycticorax nycticorax), little egret (Egretta garzetta), Chinese pond heron (Ardeola bacchus) and cattle egret (Bubulcus ibis), were collected from the upper Yangtze River (Changjiang) Basin, Southwest China in early summer of 2017. Nine out of ten target organophosphate flame retardants (PFRs) were detected in these heron egg samples. The sum of concentrations of the PFRs quantified (∑PFRs) ranged from 63 to 590 pmol g-1 ww (18-185 ng g-1 ww) with a median value of 139 pmol g-1 ww (48 ng g-1 ww) among all samples. The median ∑PFRs in eggs of night herons (160 pmol g-1 ww) was higher than Chinese pond herons (median 121 pmol g-1 ww) and little egrets (median 109 pmol g-1 ww). In heron eggs, ∑PFRs were mainly contributed by tri-n-butyl phosphate (TNBP), tris (isobutyl) phosphate (TIBP), tris (1-chloro-2-propyl) phosphate (TCIPP) and tri-2-methylphenyl phosphate (TMPP). Alkyl-PFRs accounted for approximately 28%-85% (median 57%) of the nine PFRs quantified while the rest is contributed by aryl-PFRs and chlorinated PFRs. Lower levels of PFRs in little egret eggs were found upstream than downstream of the Yangtze. In addition, the daily intakes of PFRs through ingestion of heron eggs were estimated at lower levels.

Sources of polychlorinated dibenzo-p-dioxins and dibenzofurans to Baltic Sea herring.

Levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in herring (Clupea harengus) remain high in several parts of the Baltic Sea, despite declines in PCDD/F emissions since the 1980s. The reasons behind this are not well understood. This study applied a statistical modeling approach where sources of PCDD/Fs that contaminate Baltic biota were quantitatively assessed by analyzing existing datasets. PCDD/F patterns were extracted from a herring dataset using positive matrix factorization (PMF). The extracted biota patterns were transformed into sediment patterns using fish-to-sediment transformation factors, and the resulting patterns were compared with known source PCDD/F patterns. The model distinguished three model patterns, which explained 85% of the data. These patterns were matched to tetra-chlorophenol (TCP), penta-chlorophenol/atmospheric background (PCP/AB), and thermal source patterns, respectively. The thermal source was the largest contributor to toxic equivalents (TEQ) in herring, but the level decreased from 42 ±â€¯9.0 pg TEQ g-1 lipid weight (lw) before year 2000 (pre-2000) to 15 ±â€¯2.4 pg TEQ g-1 lw post-2000, i.e., a decline of around one-third in the original TEQ concentration. The contribution of TCP more than doubled, from 2.1 ±â€¯0.62 pg TEQ g-1 lw to 5.6 ±â€¯1.1 pg TEQ g-1 lw, and the relative contribution of PCP/AB also increased. These increasing trends suggest that, as primary air emissions of PCDD/Fs are managed and levels decline, the impact of TCP and PCP/AB sources on Baltic Sea biota will become more important over time and that PCDD/F-contaminated sites in coastal areas and marine environments require more attention.

Temporal trends of persistent organic pollutants in Arctic marine and freshwater biota.

More than 1000 time-series of persistent organic pollutants (POPs) in Arctic biota from marine and freshwater ecosystems some extending back to the beginning of 1980s were analyzed using a robust statistical method. The Arctic area encompassed extended from Alaska, USA in the west to northern Scandinavian in the east, with data gaps for Arctic Russia and Arctic Finland. The aim was to investigate whether temporal trends for different animal groups and matrices were consistent across a larger geographical area. In general, legacy POPs showed decreasing concentrations over the last two to three decades, which were most pronounced for α-HCH and least pronounced for HCB and ß-HCH. Few time-series of legacy POPs showed increasing trends and only at sites suspected to be influenced by local source. The brominated flame retardant congener BDE-47 showed a typical trend of increasing concentration up to approximately the mid-2000s followed by a decreasing concentration. A similar trend was found for perfluorooctane sulfonic acid (PFOS). These trends are likely related to the relatively recent introduction of national and international controls of hexa- and hepta-BDE congeners and the voluntary phase-out of PFOS production in the USA in 2000. Hexabromocyclododecane (HBCDD) was the only compound in this study showing a consistent increasing trend. Only 12% of the long-term time-series were able to detect a 5% annual change with a statistical power of 80% at α < 0.05. The remaining 88% of time-series need additional years of data collection before fulfilling these statistical requirements. In the case of the organochlorine long-term time-series, 45% of these would require >20 years monitoring before this requirement would be fulfilled.

Inter-individual, inter-city, and temporal trends of per- and polyfluoroalkyl substances in human milk from Swedish mothers between 1972 and 2016.

Inter-individual, inter-city, and temporal trends of 19 per- and polyfluoroalkyl substances (PFASs) were investigated in human milk collected in Stockholm (1972-2016) and Gothenburg (2007-2015), Sweden. The concentrations of perfluorohexane sulfonate (PFHxS), perfluorononanoate (PFNA), perfluorodecanoate (PFDA), perfluoroundecanoate (PFUnDA), and perfluorotridecanoate (PFTrDA) in human milk from Stockholm increased significantly over the entire monitoring periods, whereas branched (Br) and linear (L) isomers of perfluorooctane sulfonamide (FOSA) decreased. In human milk from Gothenburg, significant downward trends were detected for perfluorododecanoate (PFDoDA), PFHxS and Br-perfluorooctane sulfonate (Br-PFOS) over the last decade. This declining trend was also observed for perfluorohexanoate (PFHxA), PFHxS, perfluorooctanoate (PFOA) and Br-PFOS in Stockholm over the same time period. No significant differences were observed in concentrations or relative PFAS profiles between Stockholm and Gothenburg. However, a comparison of the PFAS profile in Stockholm milk revealed distinct profiles for the time periods 1972-1996, 2000-2012, and 2013-2016, reflecting a shift in exposure over time. The lower bound estimated daily intake (EDI) for ∑PFAS concentrations in infants ranged from 7.1-40 ng per kg body weight per day (ng/kg bw/d) in Stockholm and from 5.2-25 ng/kg bw/d in Gothenburg over the studied time period, consistent with other European countries. Overall these data indicate that exposure to some legacy PFASs via breastmilk is declining, presumably as a result of regulation and phase-out initiatives. However, increasing concentrations for other PFASs and a shift in the overall PFAS profile in recent years may pose an ongoing health risk to infants.

Nontarget Screening and Time-Trend Analysis of Sewage Sludge Contaminants via Two-Dimensional Gas Chromatography-High Resolution Mass Spectrometry.

Nondestructive sample cleanup and comprehensive two-dimensional gas chromatography (GC×GC) high-resolution mass spectrometry (HRMS) analysis generated a massive amount of data that could be used for nontarget screening purposes. We present a data reduction and prioritization strategy that involves time-trend analysis of nontarget data. Sewage sludge collected between 2005 and 2015 in Stockholm (Sweden) was retrieved from an environmental specimen bank, extracted, and analyzed by GC×GC-HRMS. After data alignment features with high blank levels, artifacts and low detection frequency were removed. Features that appeared in four to six out of ten years were reprocessed to fill in gaps. The total number of compounds was reduced by more than 97% from almost 60 000 to almost 1500. The remaining compounds were analyzed for monotonic (log-linear) and nonmonotonic (smoother) time trends. In total, 192 compounds with log-linear trends and 120 compounds with nonmonotonic trends were obtained, respectively. Most compounds described by a log-linear trend exhibited decreasing trends and were traffic-related. Compounds with increasing trends included UV-filters, alkyl-phenols, and flavor and fragrances, which often could be linked to trade statistics. We have shown that nontarget screening and stepwise reduction of data provides a simple way of revealing significant changes in emissions of chemicals in society.

Signals from the south; humpback whales carry messages of Antarctic sea-ice ecosystem variability.

Southern hemisphere humpback whales (Megaptera novaeangliae) rely on summer prey abundance of Antarctic krill (Euphausia superba) to fuel one of the longest-known mammalian migrations on the planet. It is hypothesized that this species, already adapted to endure metabolic extremes, will be one of the first Antarctic consumers to show measurable physiological change in response to fluctuating prey availability in a changing climate; and as such, a powerful sentinel candidate for the Antarctic sea-ice ecosystem. Here, we targeted the sentinel parameters of humpback whale adiposity and diet, using novel, as well as established, chemical and biochemical markers, and assembled a time trend spanning 8 years. We show the synchronous, inter-annual oscillation of two measures of humpback whale adiposity with Southern Ocean environmental variables and climate indices. Furthermore, bulk stable isotope signatures provide clear indication of dietary compensation strategies, or a lower trophic level isotopic change, following years indicated as leaner years for the whales. The observed synchronicity of humpback whale adiposity and dietary markers, with climate patterns in the Southern Ocean, lends strength to the role of humpback whales as powerful Antarctic sea-ice ecosystem sentinels. The work carries significant potential to reform current ecosystem surveillance in the Antarctic region.

Persistent Organic Pollutants in the East Antarctic Atmosphere: Inter-Annual Observations from 2010 to 2015 Using High-Flow-Through Passive Sampling.

In the first multiyear sampling effort for POPs in the eastern Antarctic atmosphere, 32 PCBs and 38 organochlorine pesticides were targeted in air collected with a high-flow-through passive sampler. Agricultural chemicals were found to dominate atmospheric profiles, in particular HCB and endosulfan-I, with average concentrations of 12 600 and 550 fg/m3, respectively. HCB showed higher concentrations in the austral summer, indicative of local, temperature-dependent volatilisation, while endosulfan-I appeared to show fresh, late-austral-summer input followed by temporally decreasing levels throughout the year. The current-use herbicide, trifluralin, and the legacy pesticides mirex and toxaphene, were detected in Antarctic air for the first time. Trifluralin was observed at low but increasing levels over the five-year period. Its detection in the Antarctic atmosphere provides evidence of its persistence and long-range environmental transport capability. While a time frame of five years exceeds the duration of most Antarctic air monitoring efforts, it is projected that continuous monitoring at the decadal scale is required to detect an annual 10% change in atmospheric concentrations of key analytes. This finding emphasizes the importance of continuous, long-term monitoring efforts in polar regions, that serve a special role as sentinel environments of hemispheric chemical usage trends.