Climate change influence on the levels and trends of persistent organic pollutants (POPs) and chemicals of emerging Arctic concern (CEACs) in the Arctic physical environment - a review.

Climate change brings about significant changes in the physical environment in the Arctic. Increasing temperatures, sea ice retreat, slumping permafrost, changing sea ice regimes, glacial loss and changes in precipitation patterns can all affect how contaminants distribute within the Arctic environment and subsequently impact the Arctic ecosystems. In this review, we summarized observed evidence of the influence of climate change on contaminant circulation and transport among various Arctic environment media, including air, ice, snow, permafrost, fresh water and the marine environment. We have also drawn on parallel examples observed in Antarctica and the Tibetan Plateau, to broaden the discussion on how climate change may influence contaminant fate in similar cold-climate ecosystems. Significant knowledge gaps on indirect effects of climate change on contaminants in the Arctic environment, including those of extreme weather events, increase in forests fires, and enhanced human activities leading to new local contaminant emissions, have been identified. Enhanced mobilization of contaminants to marine and freshwater ecosystems has been observed as a result of climate change, but better linkages need to be made between these observed effects with subsequent exposure and accumulation of contaminants in biota. Emerging issues include those of Arctic contamination by microplastics and higher molecular weight halogenated natural products (hHNPs) and the implications of such contamination in a changing Arctic environment is explored.

Atmospheric Deposition of Organochlorine Pesticides and Industrial Compounds to Seasonal Surface Snow at Four Glacier Sites on Svalbard, 2013-2014.

Winter snow from four glacial sites on Svalbard was analyzed for atmospheric deposition of 36 organochlorine pesticides (OCPs) and 7 industrial compounds (OCICs) by GC-high-resolution MS. Thirteen of the OCPs and all OCICs were detected at all sites. Sampling sites are 230 km apart from west to east, but are at varying elevations, ranging from 700 to 1202 m a.s.l. Total OCP flux was greater than total OCIC at all sites and was 5 times greater at Lomonosovfonna, and 3 times greater at Austfonna, the most easterly site. Chlorpyrifos dominated OCP flux at Lomonosovfonna (81.7 pg cm-2 yr-1) and Kongsvegen (60.6 pg cm-2 yr-1), and at Austfonna, but not at Holtedahlfonna where dieldrin dominated. trans-chlordane was a major contributor to OCPs. These three pesticides comprised at least 50% of total OCP at each site. OCIC flux was dominated by pentachloroanisole (PCA) at Lomonosovfonna (23.5 pg cm-2 yr-1) and Kongsvegen (14.1 pg cm-2 yr-1). PCA and hexachlorobenzene comprised at least 63% of all OCICs at each site. Air mass frequency from likely source areas showed that Austfonna had the most frequent long-distance air flow, but showed lower amounts of chlorpyrifos and PCA, suggesting local sources of these compounds to other sites.

Atmospheric deposition of polychlorinated biphenyls to seasonal surface snow at four glacier sites on Svalbard, 2013-2014.

During spring 2014 we collected annual surface snow from four glacial sites on Svalbard, an archipelago in the European Arctic. The sampling sites are 230 km apart from west to east, but are at varying elevations, affecting local atmospheric contaminant inputs. Samples were analyzed for 209 polychlorinated biphenyl (PCB) congeners. The western sites, Holtedahlfonna and Kongsvegen, had the highest ∑PCB flux (26.7 pg cm-2 yr-1 at Kongsvegen) while the lowest was at Lomonosovfonna, in central Svalbard (14.4 pg cm-2 yr-1). The greatest difference between sites was the trichlorobiphenyl homologue which was nearly four times greater at Kongsvegen than the eastern site at Austfonna. The most concentrated congeners at each site were PCB-52, 70 + 74, 95, 101, 110 comprising 32-39% of ∑PCB, similar to Clophen 40 which is comprised 27% of these congeners. Similar variance of these congeners in samples and Clophen 40 was verified by principal components analysis. Air mass back trajectories from likely source areas for all sites were similar, indicating no difference in frequency or distribution of PCB from long-distances, suggesting local PCB sources contributing to Kongsvegen. We found 2,3-DiCB (PCB-5) and 3,3'-DiCB (PCB-11) at all sites; neither was found in western commercial PCB mixtures. PCB-5 may be from the Russian PCB product "Trichlorobiphenyl" or is residue from production of pigment violet 23. PCB-11 may come from waste incineration in northern Europe containing various pigments. These results, in comparison to earlier data from Lomonosovfonna, suggest that PCB inputs are variable and are not declining over time.

Polychlorinated Biphenyls in Tree Bark near Former Manufacturing and Incineration Facilities in Sauget, Illinois, United States.

We collected 27 tree bark samples near Sauget, IL, where 373 000 mt of polychlorinated biphenyls (PCB) was produced between 1936 and 1977 and 10 245 mt was incinerated from 1971 to 1977. Our goal was observe PCB distribution and apparent movement to residential sites, where 24 of 27 samples were collected. Only one of several waste sites was accessible for sampling. We analyzed for 209 PCB congeners, and 85 peaks are reported (other congeners either coeluted or were near or less than the detection limit). Concentrations of ∑PCB ranged from 190 952 to 2 383 988 pg g lipid(-1); 24 of 27 samples had less than 50% of the maximum concentration. Two samples with the highest ∑PCB concentrations were downwind from the plant site in residential areas, but both were among the farthest away from the production facility. One high-concentration sample was near the waste site. The three highest concentrations were in trees that were less than 20 years old, showing recent atmospheric PCB mobility. The percentage of ∑PCB distributions showed a consistent but variable pattern of diCB to nonaCB congeners. DecaCB was inconsistent, because PCB-209, which was manufactured at the site in Aroclor 1270 and 1271, was the most abundant congener in 10 of the samples but lower in others.

Chlorinated dibenzo-p-dioxin and dibenzofuran congener and homologue distributions in tree bark from Sauget, Illinois, U.S.

Polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) are ubiquitous urban/industrial contaminants found in tree bark, which acts as a long-term passive atmospheric sampler. Twenty seven bark samples (tree age 8­92 years) were collected from residential and industrial areas near Sauget, IL to identify the trends of 2,3,7,8-Cl PCDD & PCDF congener distributions, toxic equivalents (TEQ), and PCDD & PCDF homologue distributions. The Sauget area is heavily industrialized, with a long history of chlorine production, and is the largest single contributor to air pollution exposure risk in St. Louis. Analysis of seven 2,3,7,8 Cl-substituted PCDD and 10 PCDF congeners showed ∑PCDD7 ranging from 2214 to 71821 pg g(­1) lipid and ∑PCDF10 from 355 to 13707 pg g(­1) lipid, the highest in trees <20 years old in both cases. OctaCCD and octaCDF respectively dominated ∑PCDD7 (89% average) and ∑PCDF10 (57% average). The 2,3,7,8-Cl congener profiles showed slight differences among samples showing that all were affected by similar sources but at different magnitudes. ∑TEQ ranged from 35 to 624 pg g(­1) lipid, dominated by 1,2,3,7,8-PeCDD (average = 41.3% of total TEQ). Tetra-Cl through hepta-Cl homologues were dominated by non-2,3,7,8-Cl compounds for both CDD and CDF. Homologue profiles for 26 samples had a "sink" profile dominated by octaCDD, whereas one sample showed effects of a local source.

Organophosphate and halogenated flame retardants in atmospheric particles from a European Arctic site.

Levels of 13 organophosphate esters (OPEs) and 45 brominated and chlorinated flame retardants (BFRs) were measured in particle phase atmospheric samples collected at Longyearbyen on Svalbard in the European Arctic from September 2012 to May 2013. Total OPE (ΣOPEs) concentrations ranged from 33 to 1450 pg/m3, with the mean ΣOPE concentration of 430±57 pg/m3. The nonchlorinated tri-n-butyl phosphate (TnBP) and 2-ethylhexyl-diphenyl phosphate (EHDPP) were the most abundant OPE congeners measured, and the sum of all nonchlorinated OPE concentrations comprised ∼75% of the ΣOPE concentrations. The most abundant chlorinated OPE was tris(1-chloro-2-propyl) phosphate (TCPP). Total BFR concentrations (ΣBFRs) were in the range of 3-77 pg/m3, with a mean concentration of 15±3 pg/m3. 2-Ethylhexyl-2,3,4,5-tetrabromobenzoate (TBB) and bis(2-ethylhexyl)tetrabromophthalate (TBPH) were among the relatively abundant BFRs measured in these samples and comprised ∼46% and 17% of ΣBFR concentrations, respectively. Total PBDE (ΣPBDE) concentrations constituted ∼37% of ΣBFR concentrations on average and ranged from 1 to 31 pg/m3. The most abundant PBDE congener was BDE-209, which contributed 24% to ΣPBDE concentrations. Dechlorane Plus (DP) was detected in all of the samples, and ΣDP concentrations (syn-+anti-DP concentrations) ranged from 0.05 to 5 pg/m3. Overall, ΣOPE concentrations were 1-2 orders of magnitude higher than the ΣBFR concentrations.

Deposition history of polychlorinated biphenyls to the Lomonosovfonna Glacier, Svalbard: a 209 congener analysis.

A 37 m deep ice core representing 1957-2009 and snow from 2009 to 2010 were collected on the Lomonosovfonna glacier, Svalbard (78.82° N; 17.43° E) and analyzed for 209 polychlorinated biphenyl (PCB) congeners using high-resolution mass spectrometry. Congener profiles in all samples showed the prevalence of tetra- and pentachlorobiphenyls, dominated in all samples by PCB-44, PCB-52, PCB-70 + PCB-74, PCB-87 + PCB-97, PCB-95, PCB-99, PCB-101, and PCB-110. The ∑PCB flux varied over time, but the peak flux, ∼19 pg cm(-2) year(-1) from 1957 to 1966, recurred in 1974-1983, 1998-2009, and 2009-2010. The minimum was 5.75 pg cm(-2) year(-1) in 1989-1998, following a 15 year decline. Peak ∑PCB fluxes here are lower than measured in the Canadian Arctic. The analysis of all 209 congeners revealed that PCB-11 (3,3'-dichlorobiphenyl) was present in all samples, representing 0.9-4.5% of ∑PCB. PCB-11 was not produced in a commercial PCB product, and its source to the Arctic has not been well-characterized; however, our results confirm that the sources to Lomonosovfonna have been active since 1957. The higher fluxes of ∑PCB correspond to periods when average 5 day air mass back trajectories have a frequency of 8-10% and reach 60° N or beyond over northern Europe and western Russia or the North Sea into the U.K.

Deposition history of brominated flame retardant compounds in an ice core from Holtedahlfonna, Svalbard, Norway.

Brominated flame retardants (BFRs) have been found in Arctic wildlife, lake sediment, and air. To identify the atmospheric BFR deposition history on Svalbard, Norway, we analyzed 19 BFRs, including hexabromocyclododecane (HBCD), 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), decabromodiphenyl ethane (DBDPE), pentabromoethylbenzene (PBEB), and 15 polybrominated diphenyl ether congeners (PBDE) in the upper 34 m of an ice core (representing 1953-2005) from Holtedahlfonna, the western-most ice sheet on Svalbard. All of the non-PBDE compounds were detected in nearly continuous profiles in the core. Seven PBDEs were not observed above background (28, 47, 66, 100, 99, 154, 153), while 4 were found in 1 or 2 of 6 segments (17, 85, 138, 183). BDEs-49, 71, 190, 209 had nearly continuous profiles but only BDE-209 in large amounts. The greatest inputs were HBCD and BDE-209, 910, and 320 pg cm(-2) yr(-1) from 1995-2005. DBDPE, BTBPE, and PBEB show nearly continuous input growth in recent core segments, but all were <6 pg cm(-2) yr(-1). Long-range atmospheric processes may have moved these particle-bound BFRs to the site, probably during the Arctic haze season. Average air mass trajectories over 10 years show >75% of atmospheric flow to Holtedahlfonna coming from Eurasia during haze periods (March and April).

History of Inuit community excretion of polychlorinated biphenyls recorded in sewage lake sediments.

Exposure to polychlorinated biphenyls (PCBs) is high among the Inuit resulting from ingestion of contaminated wild "country" foods. These contaminants originate in urban/industrial areas and reach the Arctic by long-range atmospheric transport. Ingested PCBs eventually equilibrate into various body components, including feces, which become an indication of body burden. Bulk domestic sewage residue from a community will accumulate PCBs from feces; long-term accumulated sediments from a sewage treatment system are a historical indicator of changes in community-wide PCB excretion. In this study, sediment cores were collected from the domestic sewage treatment lake, known as Annak, for the Inuit Hamlet of Sanikiluaq, Canada (established 1967), and were dated (Pb-210, Cs-137) and analyzed for 127 PCB congeners. We focused our attention on the 47 congeners that were observed consistently. Atmospheric and local inputs to a nearby lake accounted for local background. PCB inputs from sewage grew rapidly from the late 1960s until 1990. The maximum 47 congener SigmaPCB excretion occurred in approximately 1989 (11116 ng person(-1)d(-1)); all sewage PCB inputs were dominated by PCB 153, PCB 138 and PCB 180. PCB ingestion from a Sanikiluaq food survey in 1989 for 11 of the most highly concentrated PCB congeners (7270 ng person(-1)d(-1)) was the same as our excretion estimate for the same congeners (7348 ng person(-1)d(-1)) that year, suggesting that by the late 1980s, the ingested amount of PCB was similar to what was excreted every day, although the latter is a reflection of body burden and not short-term exposure.

Endosulfan, a global pesticide: a review of its fate in the environment and occurrence in the Arctic.

This review investigates the fate and behaviour of endosulfan, a current-use organochlorine pesticide, in temperate environments and the Arctic. Usage data and patterns, physical-chemical properties, environmental partitioning and degradation, environmental levels, global distribution and temporal trends are evaluated and discussed in the context of criteria that designate a substance as a persistent organic pollutant. Endosulfan is one of the most abundant OC pesticides in the global atmosphere and is capable of undergoing long range transport to remote locations such as the Arctic. Degradation of the two isomers, alpha- and beta-endosulfan, does occur in temperate/tropical soil and aquatic systems, both by abiotic and biotic processes, although this is highly dependent on the prevailing environmental conditions. Endosulfan sulfate is the major metabolite and this recalcitrant compound has been detected in air and is present in remote mountain lake sediments, although in comparison to alpha-endosulfan, data for this compound in the wider environment are lacking. Temporal trends from ice/snow cores as well as mountain lake sediments reveal a marked increase in endosulfan accumulation from the 1980s onwards. Furthermore, unlike other 'legacy' OC pesticides, levels of alpha-endosulfan do not show a decline in atmospheric monitoring data, reflecting ongoing use of this pesticide in the northern hemisphere. Endosulfan is present at low concentrations (relative to the pesticide, lindane) in surface Arctic Ocean waters, with the atmosphere likely to be the major contemporary source. Residues of endosulfan have been detected in marine biota for different geographical regions of the Arctic, with higher bioaccumulation factors (>10(3)-10(7)) for zooplankton and various species of fish, compared to studies in warmer/temperate systems. Endosulfan is present in marine mammals, although there is uncertainty in the various Arctic biota datasets due to differences in analytical techniques. For some biota, biomagnification factors for alpha-endosulfan are >1, notably from fish to seal, although there is a wide variability in values between the same species for different regions of the Arctic. There is little if any evidence of trophic magnification of alpha-endosulfan in well-defined marine foodwebs, with some evidence of bio-dilution at higher trophic levels, presumably due to increased metabolism. Endosulfan does fulfil several of the criteria under the UNEP Stockholm Convention for designation as a persistent organic pollutant. The alpha- and beta-isomer have similar physical-chemical properties and environmental behaviour to some of the obsolete organochlorine pesticides, although an assessment of their persistence and toxicity should be viewed alongside endosulfan sulfate, as 'Sigmaendosulfan'. Persistence of 'Sigmaendosulfan' coupled to ongoing use of endosulfan pesticides, will ensure continued long-range transport and contamination of remote environments.

Current use pesticides in Arctic media; 2000-2007.

This review will summarize the levels of selected current use pesticides (CUPs) that have been identified and reported in Arctic media (i.e. air, water, sediment, and biota) since the year 2000. Almost all of the 10 CUPs (chlorothalonil, chlorpyrifos, dacthal, diazinon, dicofol, lindane, methoxychlor, pentachloronitrobenzene (PCNB), pentachlorophenol, and trifluralin) examined in the review currently are, or have been, high production volume chemicals i.e. >1M lbs/y in USA or >1000 t/y globally. Characteristic travel distances for the 10 chemicals range from 55 km (methoxychlor) to 12,100 km (PCNB). Surveys and long-term monitoring studies have demonstrated the presence of 9 of the 10 CUPs included in this review in the Arctic environment. Only dicofol has not been reported. The presence of these chemicals has mainly been reported in high volume air samples and in snow from Arctic ice caps and lake catchments. There are many other CUPs registered for use which have not been determined in Arctic environments. The discovery of the CUPs currently measured in the Arctic has been mainly serendipitous, a result of analyzing some samples using the same suite of analytes as used for studies in mid-latitude locations. A more systematic approach is needed to assess whether other CUPs might be accumulating in the arctic and ultimately to assess whether their presence has any significance biologically or results in risks for human consumers.

PCB, PCDD and PCDF congener profiles in two types of Aroclor 1254.

Monsanto produced two distinct variants of Aroclor 1254. The late-production variant resulted from a change in Monsanto's manufacturing process in the early 1970s. Previous literature had reported that the late-production variant was produced from 1974 to 1976, but subsequent work has identified a sample known to be obtained in 1972. In this paper, we present congener-specific PCB and PCDD/F data for this 1972 late-production sample, and a brief historical record of late-production Aroclor 1254.

Polychlorinated biphenyls in tree bark near a former manufacturing plant in Anniston, Alabama.

Tree bark samples were collected to identify the relative amounts and congener profiles of atmospheric polychlorinated biphenyls dissolved into bark lipids from the gas phase in Anniston, Alabama, USA, where PCBs were manufactured from the 1920s until 1971. The area is heavily contaminated with PCBs: At least 4550 metric tons (mt) of PCB and 14000 mt of PCB distillation residue, known as Montar, remain buried in two landfills near the plant site. A minimum of 20.5 mt of PCBs were emitted to the atmosphere by the plant between 1953 and 1971 based on emissions figures for 1970. Bark results show that total PCB concentrations range over more than three orders of magnitude from 171927 ng/g lipid near the plant/landfill area, dropping exponentially to 35 ng/g lipid at a distance of about 7 km. The exponential trend is highly correlated (r=-0.77) and significant (p<0.05). The most concentrated tree started growing after 1971 showing that atmospheric PCB concentrations remained high after PCB production ended. All PCB congener profiles show persistent congeners 31+28, 52, 66, 153, 138, and 180. Congener profiles from trees growing near the plant/landfill all have somewhat similar profiles but those growing during PCB production show high molecular mass compounds not usually found in the atmosphere and not found in younger trees, even in the most concentrated sample. We believe that high-temperature Montar disposal released high molecular mass PCBs into the gas phase which were dissolved into older tree bark lipids.

Current-use and legacy pesticide history in the Austfonna Ice Cap, Svalbard, Norway.

The Svalbard archipelago in arctic Norway receives considerable semivolatile organic contaminant (SOC) inputs from the atmosphere. To measure the history of net SOC accumulation there, we analyzed the upper 40 m of an ice core from Austfonna, the largest ice cap in Eurasia, for several legacy organochlorine (OC) compounds and current-use pesticides (CUPs) including organophosphorus (OP), triazine, dinitroaniline, and chloroacetamide compounds. Five OP compounds (chlorpyrifos, terbufos, diazinon, methyl parathion, and fenitrothion), two OCs (methoxychlor and dieldrin), and metolachlor--an herbicide--had historical profiles in the core. The highest OC concentration observed was aldrin (69.0 ng L(-1)) in the surface sample (1992-1998). The most concentrated OP was dimethoate (87.0 ng L(-1)) between 1986 and 1992. The surface sample also had highest concentrations of pendimethalin (herbicide, 18.6 ng L(-1)) and flutriafol, the lone observed fungicide (9.6 ng L(-1)). The apparent atmospheric persistence of CUPs likely results from little or no oxidation by OH* during the dark polar winter and in spring. Long-range atmospheric pesticide transport to Svalbard from Eurasia is influenced by the positive state of the North Atlantic Oscillation Index since 1980 and also by occasional fast-moving summer air masses from northern Eurasian croplands.

History of Inuit community exposure to lead, cadmium, and mercury in sewage lake sediments.

Exposure to lead, cadmium, and mercury is known to be high in many arctic Inuit communities. These metals are emitted from industrial and urban sources, are distributed by long-range atmospheric transport to remote regions, and are found in Inuit country foods. Current community exposure to these metals can be measured in food, but feces and urine are also excellent indicators of total exposure from ingestion and inhalation because a high percentage of each metal is excreted. Bulk domestic sewage or its residue in a waste treatment system is a good substitute measure. Domestic waste treatment systems that accumulate metals in sediment provide an accurate historical record of changes in ingestion or inhalation. We collected sediment cores from an arctic lake used for facultative domestic sewage treatment to identify the history of community exposure to Pb, Cd, and Hg. Cores were dated and fluxes were measured for each metal. A nearby lake was sampled to measure combined background and atmospheric inputs, which were subtracted from sewage lake data. Pb, Cd, and Hg inputs from sewage grew rapidly after the onset of waste disposal in the late 1960s and exceeded the rate of population growth in the contributing community from 1970 to 1990. The daily per-person Pb input in 1990 (720,000 ng/person per day) exceeded the tolerable daily intake level. The Cd input (48,000 ng/person per day) and Hg input (19,000 ng/person per day) were below the respective TDI levels at the time.

Variable air temperature response of gas-phase atmospheric polychlorinated biphenyls near a former manufacturing facility.

Many investigations of gas-phase atmospheric PCB show a strong relationship between concentration and air temperature, especially near PCB sources. Comparative gas-phase atmospheric PCB trends during an annual temperature regime at two sites near a former PCB manufacturing plant and nearby PCB landfills in Anniston, AL, indicate a departure from this trend. The Mars Hill sampling site, located closest to the plant and landfills, shows an annual average sigmaPCB concentration of 27 ng m(-3) (ranging from 8.7 to 82 ng m(-3)) three times the average at Carter, 1.5 km away (9 ng m(-3), ranging from 1.1 to 39). However, total PCB and congener concentrations vary more with air temperature at Carter where PCB are evaporating from surfaces during warmer weather. The slopes of the Clausius-Clapeyron plots of 18 of the most concentrated congeners representing dichloro- through heptachlorobiphenyl homologues are significantly higher at the Carter site. While some of the atmospheric PCB at Mars Hill is derived from ground surface evaporation, the source of much of it apparently is the material buried in the landfills, which has different thermal properties than surface materials and is not in equilibrium with air temperature.