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Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous organic contaminants, which are found in soils throughout the U.S. The objective of this study was to determine the background concentrations, distributions, and sources of 16 USEPA priority PAHs in two urban soils. A total of 114 soil samples were collected from two large cities in Florida: Orlando and Tampa. The results showed that soils were dominated by high molecular weight PAHs in both cities. The average ∑16-PAHs in Orlando and Tampa soils were 3227 and 4562 μg kg−1, respectively. The averages of 7 carcinogenic PAHs based on the benzo[a]pyrene-equivalent (BaP-EQ) concentrations in the two cities were 452 and 802 μg kg−1. BaP-EQ concentrations in 60–62% of samples were higher than the Florida Soil Cleanup Target Level (FSCTL) for residential soils at 100 μg kg−1 and 20–25% of samples were higher than FSCTL for industrial soils at 700 μg kg−1. Based on molecular diagnostic ratios and PMF modeling, major sources of soil PAHs in both cities were similar, mainly from pyrogenic sources including vehicle emissions, and biomass and coal combustion. Based on ArcGIS mapping, PAH concentrations in soils near business districts and high traffic roads were higher. Thus, it is important to consider background PAH concentrations in urban soils when considering soil remediation.

Sediment cores from 47 inland lakes in Michigan, USA were used to assess spatial and temporal trends in loadings of mercury (Hg). Focusing/background corrected accumulation rates and inventories and peak concentrations were used to examine: 1) responses of loadings to post-1990 reductions in emissions, 2) if spatial trends are consistent with modeled Hg deposition and 3) evidence for local and distal inputs. Results showed that decreases in concentrations and anthropogenic accumulation rates of Hg were consistent with recent reductions in emissions of Hg. Most lakes exhibiting a decreasing trend were located within an area with the most emission sources. Not all lakes showed the decreasing trend with some showing increases or no change. These lakes tended to be in the northern portion of the state. In all lakes, current concentrations of Hg remain greater than long-term, historical, background concentrations. Sub-regional mean inventories and mean decadal accumulation rates exhibited a south to north gradient, consistent with previously modeled spatial trends. However, individual lake inventories and rates of accumulation compared at shorter times scales varied among lakes. Evidence for event deposition (e.g., volcanic eruptions, manufacturing) was also variable among lakes. These results suggest influence of more distal inputs of Hg, perhaps driven by well-mixed, global sources. Cause(s) of variability on shorter time scales (e.g., events) needs further work. Finally, the results reveal that understanding risks to humans and ecosystems due to exposure to Hg and developing effective abatement policy is challenging.

In this study, the removal of pharmaceuticals from wastewater as predicted by SimpleTreat 4.0 was evaluated. Field data obtained from literature of 43 pharmaceuticals, measured in 51 different activated sludge WWTPs were used. Based on reported influent concentrations, the effluent concentrations were calculated with SimpleTreat 4.0 and compared to measured effluent concentrations. The model predicts effluent concentrations mostly within a factor of 10, using the specific WWTP parameters as well as SimpleTreat default parameters, while it systematically underestimates concentrations in secondary sludge. This may be caused by unexpected sorption, resulting from variability in WWTP operating conditions, and/or QSAR applicability domain mismatch and background concentrations prior to measurements. Moreover, variability in detection techniques and sampling methods can cause uncertainty in measured concentration levels. To find possible structural improvements, we also evaluated SimpleTreat 4.0 using several specific datasets with different degrees of uncertainty and variability. This evaluation verified that the most influencing parameters for water effluent predictions were biodegradation and the hydraulic retention time. Results showed that model performance is highly dependent on the nature and quality, i.e. degree of uncertainty, of the data. The default values for reactor settings in SimpleTreat result in realistic predictions.

Geochemical studies of 174 sediment cores collected by the MAREANO mapping program in Norwegian waters of the North Atlantic Ocean give new sets of values of background concentrations (BCs) for polycyclic aromatic hydrocarbons (PAHs) for the studied regions. The study is based on deep core sediment samples representing background levels of PAHs. The samples selected were only from the deeper parts of undisturbed sediment cores with low, stable concentrations of petrogenic and pyrogenic PAHs, with low variation for individual PAH compounds between the samples within the same core, and from below the parts of the cores dated with 210Pb to approximately the last 100-150 years. The results show that the main part of the studied area has BCs different from those previously established by OSPAR Commission (OSPAR) for the North-East Atlantic. Another area in central Barents Sea has a separate set of BCs of pyrogenic PAHs, apparently due to the influence from marginal ice zone mechanisms. A third area with its own set of BCs has been established for north-western Barents Sea off the coast of Svalbard, due to high natural contents of PAHs in this area. BCs for several PAHs not included in the present OSPAR list are also provided.

Polychlorinated dibenzo-p-dioxins (PCDDs) occur naturally in ball clay at elevated concentrations. Thus, persons who habitually work with clay may be at risk for exposure to PCDDs. An earlier case report provided some evidence of elevated PCDD levels in serum for long-term hobby ceramicists; however, no previous study has measured serum dioxin concentrations among ceramicists. This study measured PCDD serum levels for 27 individuals involved in ceramics making. The average residual, defined as the average of the [log measured serum lipid concentration – log background serum lipid concentration], was calculated and then tested to determine whether it was significantly different from zero. The p-values for the average residuals indicated that the serum lipid concentrations for several PCDD congeners were elevated relative to background. The number of significant residuals increased dramatically if the background concentrations were adjusted to account for the fact that they were not contemporaneous with the measurements for the ceramicists. The ratio of the 1,2,3,6,7,8-HxCDD concentration to the 1,2,3,7,8,9-HxCDD concentration was greater than 1.0, unlike in ball clay, suggesting that although long-term working with ball clay elevates the PCDD levels in serum somewhat, it is not the predominant source of the PCDD body burden for ceramicists.

Concentrations of PAHs and PCDD/Fs were measured throughout one year, and PCBs during the second semester, at a rural site in a natural park representative of background pollution in central Italy; results were compared with simultaneous measurements performed at an urban site in Rome 60km away. Twenty-four daily samples were collected at each site by a high-volume PM(10) sampler from February 2000 to January 2001. After ultrasonic extraction and clean-up by TLC, samples were analysed by GC-MS. Mean concentrations of benzo[a]pyrene (BaP, as a marker of carcinogenic PAHs), summation operatorPCDD/Fs and summation operator64 PCBs in Rome were, respectively: 1.1ngm(-3), 65fgWHO-TEQm(-3), 553pgm(-3). The background concentrations were, respectively: 0.016ngm(-3), 3fgWHO-TEQm(-3), and 94pgm(-3). Hence, BaP, and the other PAHs, showed the highest urban-background gradient (two orders of magnitude) and PCBs the lowest. The background pollution levels of BaP and PCDD/Fs were in agreement with the few available background/remote measurements in Europe. In Rome PAHs and PCBs, but not PCDD/Fs, were clearly seasonal; the PCDD/F TEQ was moderately correlated with BaP (P

We evaluated individual adipose tissue (subcutaneous lipomas) dioxin contamination in non-occupationally exposed persons living in France (adult patients undergoing a surgical ablation of benign lipomas), in relation to the corresponding individually evaluated mean daily dietary dioxin intake (DDDI). The diet survey (questionnaire) included information on consumption of meat, fish, milk and dairy products, from which the individual DDDI was calculated. Sixteen subjects participated in this study. DDDI ranged between 1.06 and 3.31 pg I-TEQ/kg body weight, bw (mean value: 2.05±0.72). Adipose tissue polychlorinated dibenzo- p -dioxins (PCDD)/polychlorinated dibenzofurans (PCDF) levels ranged between 18.5 and 76.9 pg I-TEQ/g lipids (mean value: 35.6±14.8). No relation was found between the DDDI and adipose tissue PCDD/PCDF concentrations. The mean DDDI in France does not fundamentally differ from those found in other industrialised countries, is within the range of 1–4 pg I-TEQ/kg/day recently suggested by WHO-ECEH/ICPS for the tolerable daily intake of dioxins. Adipose tissue PCDD/PCDFs levels are similar to levels in other European countries and USA without relation to sex or age, and can be considered representative European background concentrations. Globalisation of alimentary production leads to a similar food exposure in Western European countries, in spite of dioxins accidental selective contaminations that are epiphenomenon and thus do not have any impact in human dioxin background levels.

In order to get more information about potential health hazards due to indoor air PCBs the present study investigated the PCB indoor concentration in schools as well as the blood levels of 6 PCB-indicator congeners in teachers from these schools. 151 teachers (78 male and 73 female; mean age 48 years) from 3 contaminated and 2 control schools participated in the study. Maximal indoor air values for total PCBs (6 PCB-indicator congeners times 5) in schools ranged from 1587 to 10655 ng/m3. Blood analyses indicated an increase in mean PCB 28 level from 0.036 (control group) to 0.098 microg/l in teachers from a school with heavy contamination of low chlorinated PCB. But there was no significant increase of PCB 138, 153 and 180 in blood above the normal background concentrations in any of the contaminated schools (mean values of all groups: PCB 138 = 0.66, 153 = 0.95, 180 = 0.70 microg/l blood). The results of blood analyses and additional toxicokinetic calculations suggested that inhalative PCB-uptake in the most contaminated schools caused a minor increase above mean background-PCB concentrations in blood. In conclusion, despite high PCB indoor air levels in schools, there was only a moderate increase in blood concentrations of teachers, mainly due to congeners with low chlorination (PCB 28 to PCB 101).

The results in this study forms the beginning of the establishment of a baseline for background heavy metal concentrations in aquatic bryophytes collected in the Sudety Mts. (Poland and Czech Republic) by comparison with bryophytes in other non polluted and non industrialized areas outside the Sudety Mts. The plant elemental composition of the Sudety Mts. contains significantly more nickel, chromium and barium and significantly less zinc and mercury as compared to bryophyte samples from selected areas in the Swiss Alps.

In fireworks, organic additives with high chlorine content such as hexachlorobenzene (HCB) are used for the improvement of illumination effects. In the course of a monitoring campaign for the detection of HCB in fireworks, atmospheric concentrations of chlorobenzenes (CBs), chlorophenols (CPs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), were measured during the Swiss National holiday August 1, 2011 which is celebrated with fireworks nationwide. Samples were collected in the city of Zurich using high-volume air samplers equipped with quartz fiber filters and poly-urethane foam plugs. With one sampling period of 3h, a peak HCB concentration of 297 pg m(-3) was detected. Maximum total concentrations of pentachlorophenol and PCDD/Fs were 218 pg m(-3) and 61 fg I-TEQ m(-3), respectively. These levels are in the order of ten times above background concentrations measured one week before and two weeks after the event. Atmospheric emissions of HCB and CPs were quantified using a multimedia mass balance model to interpret the field measurements resulting in total emissions of HCB and CPs during the event of 23 g and 25 g, respectively. Based on per capita amounts this corresponds to total annual emissions from fireworks of 1.5 kg for each of the two pollutants in Switzerland. Starting from an estimation of the total worldwide emissions of HCB, in Switzerland emissions from fireworks may represent about 2-14% of total HCB releases.

CDFs and CDDs were detected in Niagara Falls air samples with total concentrations ranging from 0.07 to 53 pg/m 3 . The highest concentrations were found on days when the wind direction was from a nearby point source. Average CDF/CDD background concentrations were calculated.

6 pages, 2 figures.-- PMID: 17223182 [PubMed].-- Printed version published Apr 2007., Issue title: Halogenated Persistent Organic Pollutants Dioxin 2004 - Selected, extended and updated proceedings of the 24th International Symposium on Halogenated Environmental Organic Pollutants and POPs convened at the Technical University of Berlin, Germany, September 2004, This work summarizes the results of a ten year surveillance programme on PCDD/F in ambient air carried out in Catalonia (Spain). The study has been conducted by the Dioxin Laboratory of Spanish Council for Scientific Research (CSIC) in collaboration with the Environment Department of the Catalonian Government. 175 samples have been collected throughout Catalonia from 1994 to 2004. Different sampling locations classified as industrial, traffic, urban, suburban and rural sites have been monitored in order to find the most contaminated zones as well as the ones with expected background concentrations., The highest concentrations found in this study were determined at the industrial locations. Concentrations ranging from 5 to 1196 fg I-TEQ/m3, with a mean value of 140 fg I-TEQ/m3 and from 10 to 357 fg I-TEQ/m3, with a mean value of 72 fg I-TEQ/m3 were determined in industrial and traffic sampling points, respectively. In contrast, the lowest concentrations were found in rural stations, ranging from 5 to 45 fg I-TEQ/m3, with a mean value of 28 fg I-TEQ/m3. The PCDD/F concentration trend in Catalonian ambient air shown a clear drop of the median values occurred during the study sampling period. A decline of about 70% was observed from 1997–1998 to 2003–2004., The authors wish to thank Ms. M.G. Martrat and Mr. M.A. Adrados for sample preparation and Mr. Jordi Sauló for the mass spectrometric analyses.

The concentrations of chlorinated dibenzodioxins and dibenzofurans (PCDD/F) in human blood and in milk from non-occupationally exposed persons living in the vicinity of a municipal waste incinerator were determined. As compared to background levels in the general population in Germany the results give no indication of an enhanced body burden of PCDD/F. This is in agreement with earlier investigations in the same area, showing normal background concentrations in soil, fruit and vegetables. In conclusion, no direct health hazard related to PCDD/F — emissions from a local municipal waste incinerator may be expected.

Two office buildings were tested to determine the background surface and air concentrations of PCDFs and PCDDs. Surface samples showed higher concentrations of PCDDs than PCDFs, increase of PCDD concentration with degree of chlorination, similar concentrations of PCDFs irrespective of degree of chlorination, and significant correlations between concentrations of PCBs, and PCDFs and PCDDs. Air samples generally contained non-detectable concentrations of PCDFs and lower chlorinated PCDDs; and a predominance of higher chlorinated PCDDs. These data define a concentration baseline for PCDFs and PCDDs in these buildings, but may be indicative of the concentrations present in other office buildings.

Concentrations in the environment of polychlorinated dibenzo-p-dioxins (PCDD), and related compounds such as polychlorinated dibenzofurans (PCDF), have recently been the cause of great concern due to their suspected high toxicity. General low background concentrations of PCDD/PCDF are found in the atmosphere, sediments and the human populationl. Evidence in the sediment record suggest that there have been increases in PCDD/PCDF pollution since 19402. In this study, we present the results of a program to determine the sources, occurrence and effects of PCDD and PCDF concentrations in ambient air in Ohio at several locations.

Soil samples collected at points on a 50 km grid covering England, Wales and lowland Scotland have been analysed for PCDDs and PCDFs. Mean concentrations for a reduced data set were in the range 6.6 ng kg −1 for PCDD to 191 ng kg −1 for OCDD and from 23 ng kg −1 for PCDF to 41 ng kg −1 for HxCDF. These levels provide an indication of the background concentrations of PCDDs and PCDFs in British soils.