Polychlorinated Biphenyls (PCBs), and Polycyclic Aromatic Hydrocarbons (PAHs), in UK Air and Deposition.

Air concentrations and deposition fluxes of PCBs and PAHs are presented for 1991 and 1992 at four UK urban centres (London, Manchester, Cardiff and Stevenge). Sampling was also carried out throughout 1993 at a rural location in NW England (Hazelrigg). This monitoring programme, part of the toxic organic micropollutants survey (TOMPS), has provided the first extensive data sets for PAHs and PCBs in the UK urban and rural atmosphere. Atmospheric PCBs and PAHs were sampled every other week at each of the sites using High-Volume air samplers, equipped with glass fibre filters to collect particulate and polyurethane foam plugs to serve as vapour adsorbents. Bulk deposition was collected every month. Furthermore, atmospheric PCBs were sampled every day at the rural site, between March and June 1994, in a preliminary attempt to investigate the influence of separate meteorological episodes. At the four urban sites mean annual SigmaPAH concentrations ranged from approximately 60 - 150 ng m-3, while the mean SigmaPCB concentration ranged from 500 - 1500 pg m-3. These concentrations are the same order of magnitude as contemporary concentrations reported in other urban areas on an international basis. The lighter, predominantly vapour phase PAHs of fluorene and phenanthrene and the lower chlorinated PCB congeners, 28 and 52, dominate the atmospheric profile for both sets of compounds respectively. SigmaPAH concentrations were actually greater in the Hazelrigg atmosphere (~ factor 2) than in Manchester. This was due to significantly higher concentrations of fluorene and phenanthrene. This site and another rural site in the NW England are under the influence of local sources. Added to this, volatilisation of these lighter compounds from secondary sources such as sediments/soils/vegetation may explain the elevated concentrations during the warmer summer months. Principal components analysis highlighted the dominance of these lighter compounds in the rural atmosphere over the urban atmospheres. At Hazelrigg the SigmaPCB concentrations were lower than the urban sites by a factor of between 3-4, reflecting the lack of point sources in the rural environment. Seasonal variations were evident for the heavier PAH in both the urban and rural atmosphere. This was characterised by elevated concentrations in the winter, possibly due to increased fuel consumption for residential heating. The lighter compounds in the urban atmosphere did not show the seasonal cycling evident in the rural atmosphere, probably due to the masking effect of increased primary emissions in the winter. The SigmaPCB concentrations showed elevated concentrations in the summer at all of the sites, the vapour phase concentrations of several prominent congeners being correlated with temperature. The more chlorinated congeners showed an increased cycling amplitude from winter to summer than the less chlorinated congeners. This may be due to them being more readily exchangeable between surfaces and the atmosphere, than the lower chlorinated congeners. Partitioning between the particulate and vapour phases for the PAHs and the PCBs appears to be controlled mainly by temperature and a compound's volatility. Total suspended particulate plays a lesser role, the partitioning behaviour (calculated partition coefficients at 20°C) for six indicator congeners being similar in both the Manchester and Hazelrigg atmospheres. As surface area available for sorption is more important than just particulate concentration it is postulated here that the amount of area available at the earth's surface, particularly if covered by vegetation, will play a more important role in vapour phase sorption/desorption than atmospheric particulate. Meteorological episodes typified by high pressure anti-cyclonic systems resulted in elevated particulate phase SigmaPCB and SigmaPAH concentrations in the Cardiff and Manchester atmospheres respectively. The use of air mass back trajectories identified three separate air masses at the Hazelrigg site, when SigmaPCB concentrations varied significantly from the sampling mean. The lack of profile differences between these air masses (originating from different areas) indicate similar sources to the atmosphere, or similar processes that occur during transport that result in a uniform profile. The mean sPAH deposition flux varied from ~5 ug m-2 d-1 at the urban sites to ~2 ug m d-1 at the rural site. The mean SigmaPCB deposition flux varied from ~0. 8 ng m-2 d-1 at the urban sites to ~0. 2 ng m-2 d-1 at the rural site. Comparison with fluxes reported at rural/remote sites in north America would suggest that Hazelrigg and a site in the Lake District in NW England represent semi-urban areas; it seems that greater distances away from urban centres are required before 'true' rural fluxes are obtained. (Abstract shortened by ProQuest.)

Pesticides contaminated dust exposure, risk diagnosis and exposure markers in occupational and residential settings of Lahore, Pakistan

There are few studies documenting the dust loaded with pesticides as a potential non-dietary exposure source for occupational worker and populations living near agricultural farms and pesticides formulation plants. In present study we have evaluated the pesticide concentration in dust from potential sites and relevant health risk from dust ingestion. Furthermore, the effect of currently used pesticides was investigated on blood and urine parameters of subjects: farmer, factory worker, urban resident and rural resident and controlled subjects with presumably different levels of exposure. The urinary metabolites (TCPY and IMPY) were quantified as biomarkers of exposure to chlorpyrifos and diazinon in relation with biomarkers of effect including BuChE, LH, FSH, testosterone and oxidative stress. Results showed that chlorpyrifos and diazinon were present in higher concentration in dust and posed a high health risk to exposed subjects. The mean SOD value was high among the farmer (3048 U/g Hb) followed by factory worker (1677.6U/g Hb). The urinary biomarkers – TCPY and IMPY- were found higher in exposed subjects as compared to control. Furthermore, testosterone was found in higher concentration in factory worker than control (12.63 ng/ml vs 4.61 ng/ml respectively). A decreased BuChE activity was noticed in occupational group and significant differences were observed in control verses exposed subjects. The PCA analysis evidenced the impact of pesticides on exposure biomarkers and male reproductive hormones. The study suggests that dust contaminated with pesticides engenders significant health risk particularly related to the nervous and endocrine system, not only for occupational workers exposed to direct ingestion but also for nearby residential community. Succinctly putting: Pesticides loaded dust in the city of Lahore, being a high priority concern for the government of Pakistan, demands to be addressed

Polycyclic aromatic hydrocarbons in ocean sediments from the North Pacific to the Arctic Ocean

Abstract Eighteen polycyclic aromatic hydrocarbons (PAHs) were measured in surficial sediments along a marine transect from the North Pacific into the Arctic Ocean. The highest average Σ18PAHs concentrations were observed along the continental slope of the Canada Basin in the Arctic (68.3 ± 8.5 ng g−1 dw), followed by sediments in the Chukchi Sea shelf (49.7 ± 21.2 ng g−1 dw) and Bering Sea (39.5 ± 11.3 ng g−1 dw), while the Bering Strait (16.8 ± 7.1 ng g−1 dw) and Central Arctic Ocean sediments (13.1 ± 9.6 ng g−1 dw) had relatively lower average concentrations. The use of principal components analysis with multiple linear regression (PCA/MLR) indicated that on average oil related or petrogenic sources contributed ∼42% of the measured PAHs in the sediments and marked by higher concentrations of two methylnaphthalenes over the non-alkylated parent PAH, naphthalene. Wood and coal combustion contributed ∼32%, and high temperature pyrogenic sources contributing ∼26%. Petrogenic sources, such as oil seeps, allochthonous coal and coastally eroded material such as terrigenous sediments particularly affected the Chukchi Sea shelf and slope of the Canada Basin, while biomass and coal combustion sources appeared to have greater influence in the central Arctic Ocean, possibly due to the effects of episodic summertime forest fires

Investigating the uptake and fate of poly- and perfluoroalkylated substances (PFAS) in sea ice using an experimental sea ice chamber

Poly- and perfluoroalkyl substances (PFAS) are contaminants of emerging Arctic concern and are present in the marine environments of the polar regions. Their input to and fate within the marine cryosphere are poorly understood. We conducted a series of laboratory experiments to investigate the uptake, distribution, and release of 10 PFAS of varying carbon chain length (C4–C12) in young sea ice grown from artificial seawater (NaClsolution). We show that PFAS are incorporated into bulk sea ice during ice formation and regression analyses for individual PFAS concentrations in bulk sea ice were linearly related to salinity (r2 = 0.30 to 0.88, n = 18, p < 0.05). This shows that their distribution is strongly governed by the presence and dynamics of brine (high salinity water) within the sea ice. Furthermore, long-chain PFAS (C8–C12), were enriched in bulk ice up to 3-fold more than short-chain PFAS (C4–C7) and NaCl. This suggests that chemical partitioning of PFAS between the different phases of sea ice also plays a role in their uptake during its formation. During sea ice melt, initial meltwater fractions were highly saline and predominantly contained short-chain PFAS, whereas the later, fresher meltwater fractions predominantly contained long-chain PFAS. Our results demonstrate that in highly saline parts of sea ice (near the upper and lower interfaces and in brine channels) significant chemical enrichment (ε) of PFAS can occur with concentrations in brine channels greatly exceeding those in seawater from which it forms (e.g., for PFOA, εrinebrine = 10 ± 4). This observation has implications for biological exposure to PFAS present in brine channels, a common feature of first-year sea ice which is the dominant ice type in a warming Arctic

Pollution in the Arctic Ocean: An overview of multiple pressures and implications for ecosystem services

The Arctic is undergoing unprecedented change. Observations and models demonstrate significant perturbations to the physical and biological systems. Arctic species and ecosystems, particularly in the marine environment, are subject to a wide range of pressures from human activities, including exposure to a complex mixture of pollutants, climate change and fishing activity. These pressures affect the ecosystem services that the Arctic provides. Current international policies are attempting to support sustainable exploitation of Arctic resources with a view to balancing human wellbeing and environmental protection. However, assessments of the potential combined impacts of human activities are limited by data, particularly related to pollutants, a limited understanding of physical and biological processes, and single policies that are limited to ecosystem-level actions. This manuscript considers how, when combined, a suite of existing tools can be used to assess the impacts of pollutants in combination with other anthropogenic pressures on Arctic ecosystems, and on the services that these ecosystems provide. Recommendations are made for the advancement of targeted Arctic research to inform environmental practices and regulatory decisions

Investigating the occurrence of persistent organic pollutants in the Arctic: their atmospheric behaviour and interaction with the seasonal snow pack.

POPs in the Arctic are the focus of international concern due to their occurrence and accumulation in Arctic food webs. This paper presents an overview of the major pathways into the Arctic and details contemporary studies that have focused on the occurrence and transfer of POPs between the major Arctic compartments, highlighting areas where there is a lack of quantitative information. The behaviour of these chemicals in the Arctic atmosphere is scrutinised with respect to long-term trends and seasonal behaviour. Subtle differences between the PCBs and OC pesticides are demonstrated and related to sources outside of the Arctic as well as environmental processes within the Arctic. Unlike temperate regions, contaminant fate is strongly affected by the presence of snow and ice. A description of the high Arctic snow pack is given and the physical characteristics that determine chemical fate, namely the specific surface area of snow and wind driven ventilation, are discussed. Using a well-characterised fresh snow event observed at Alert (Canadian high Arctic) [Atmos. Environ. 36(2002) 2767] the flux of γ-HCH out of the snow is predicted following snow ageing. Under conditions of wind (10 m/s) it is estimated that ≈75% of the chemical may be re-emitted to the atmosphere within 24 h following snowfall, compared with just ≈5% under conditions of no wind. The implications of this are raised and areas of further research suggested

A novel approach to investigating indoor/outdoor pollution links : combined magnetic and PAH measurements.

In a preliminary study, paired indoor and outdoor air sampling was conducted at three locations around the city of Lancaster, UK to examine the influence of combustion sources on air quality by measuring particulate concentrations, particulate magnetic properties and polyaromatic hydrocarbons (PAHs). With one exception (an indoor suburban air sample), outdoor air samples had higher total suspended particulates (TSP), particle-bound PAH concentrations and magnetic remanence (IRM) values. IRM values were highest for the week-day, outdoor city centre samples and then declined in the sequence: Sunday, city centre > suburban/residential > Lancaster University campus. These data indicate traffic as the major particle-bound PAH, particulates and magnetic source, particularly as sampling was conducted during July in the absence of any space heating. The indoor air samples revealed a wide variation in pollutant concentrations, characterised by higher vapour levels of 2-3 ring PAHs, variable TSP concentrations and variable but generally low IRMs. The differences in PAH concentrations, TSP and IRMs between outdoor and indoor environments indicate limited ingress of outdoor air pollutants to the indoor environment in this study. Our combined PAH and magnetic data identify specific and distinctive indoor pollution signals for each of our sampled sites, reflecting distinct sources. One site, the suburban house, has anomalously high IRM, TSP and particle-bound PAHs. A possible source for these is a cast iron, wood-burning stove (even though not lit). The city centre indoor site is characterised by high TSP and very low IRMs but high values of the magnetic ratio of anhysteretic remanence:saturation remanence, indicative of ultrafine (submicrometre) magnetic grain sizes. The source for this city centre indoor signature is unidentified but may reflect the occupant smoking and/or lighting candles. The indoor campus sample was affected by loss2 on-ignition procedures carried out in a teaching laboratory. The combined PAH and magnetic analyses thus provide a sensitive and discriminatory means of identifying outdoor, trafficderived pollution, and of discriminating between different types of indoor pollution

Changing sources and environmental factors reduce the rates of decline of organochlorine pesticides in the Arctic Atmosphere.

An extensive database of organochlorine (OC) pesticide concentrations measured at the Norwegian Arctic Monitoring Station was analysed to assess longer-term trends in the Arctic atmosphere. Dynamic Harmonic Regression (DHR) is employed to investigate the seasonal and cyclical behaviour of chlordanes, DDTs and hexachlorobenzene (HCB), and to isolate underlying inter-annual trends. Although a simple comparison of annual mean concentrations (1994–2005) suggest a decline for all of the OCs investigated, the longer-term trends identified by DHR only show a significant decline for p,p'-DDT. Indeed, HCB shows an increase from 2003–2005. This is thought to be due to changes in source types and the presence of impurities in current use pesticides, together with retreating sea ice affecting air-water exchange. Changes in source types were revealed by using isomeric ratios for the chlordanes and DDTs. Declining trends in ratios of trans-chlordane/cis-chlordane (TC/CC) indicate a shift from primary sources, to more ''weathered'' secondary sources, whereas an increasing trend in o,p'-DDT/p,p'-DDT ratios indicate a shift from use of technical DDT to dicofol. Continued monitoring of these OC pesticides is required to fully understand the influence of a changing climate on the behaviour and environmental cycling of these chemicals in the Arctic as well as possible impacts from ''new'' sources