Oil sands activities north of Fort McMurray, Alberta, have intensified in recent years with a concomitant debate as to their environmental impacts. The Regional Aquatics Monitoring Program and its successor, the Joint Canada-Alberta Implementation Plan for Oil Sands Monitoring (JOSM), are the primary aquatic programs monitoring this industry. Here we examine sediment data (collected by Ekman grabs) to investigate trends and sources of polycyclic aromatic hydrocarbons (PAHs), supplementing these data with sediment core studies. Total PAH (ΣPAH) concentrations were highest at Shipyard Lake (6038 ± 2679 ng/g) in the development center and lower at Isadore's Lake (1660 ± 777 ng/g) to the north; both lakes are in the Athabasca River Valley and lie below the developments. ΣPAH concentrations were lower (622–930 ng/g) in upland lakes (Kearl, McClelland) located further away from the developments. ΣPAH concentrations increased at Shipyard Lake (2001–2014) and the Ells River mouth (1998–2014) but decreased in nearshore areas at Kearl Lake (2001–2014) and a Muskeg River (2000–2014) site. Over the longer term, ΣPAH concentrations increased in Kearl (1934–2012) and Sharkbite (1928–2010) Lakes. Further (200 km) downstream in the Athabasca River delta, ΣPAH concentrations (1029 ± 671 ng/g) increased (1999–2014) when %sands were included in the regression model; however, 50 km to the east, concentrations declined (1926–2009) in Lake Athabasca. Ten diagnostic ratios based on anthracene, phenanthrene, fluoranthene, pyrene, benz[a]anthracene, chrysene, indeno[123-cd]pyrene, dibenz[a,h]anthracene, dibenzothiophene and retene were examined to infer spatial and temporal trends in PAH sources (e.g., combustion versus petrogenic) and weathering. There was some evidence of increasing contributions of unprocessed oil sands and bitumen dust to Shipyard, Sharkbite, and Isadore's Lakes and increased combustion sources in the Athabasca River delta. Some CCME interim sediment quality guidelines were exceeded, primarily in Shipyard Lake and near presumed natural bitumen sources.

This study investigates PM2.5-bound PAHs for rural sites (Dacheng and Fangyuan) positioned close to heavy air-polluting industries in Changhua County, central Taiwan. A total of 113 PM2.5 samples with 22 PAHs collected from 2014 to 2015 were analyzed, and Positive Matrix Factorization (PMF) and diagnostic ratios of PAHs were applied to quantify potential PAH sources. The influences of local and regional sources were also explored using the conditional probability function (CPF) and potential source contribution function (PSCF) with PMF-modeled results, respectively. Annual mean concentrations of total PAHs were 2.91 ± 1.34 and 3.04 ± 1.40 ng/m3 for Dacheng and Fangyuan, respectively, and their corresponding BaPeq were measured at 0.534 ± 0.255 and 0.563 ± 0.273 ng/m3 in concentration. Seasonal variations with higher PAHs found for the winter than for the spring and summer were observed for both sites. The lifetime excess cancer risk (ECR) from inhalation exposure to PAHs was recorded as 4.7 × 10−5 overall. Potential sources of PM2.5-bound PAHs include unburned petroleum and traffic emissions (42%), steel industry and coal combustion (31%), and petroleum and oil burning (27%), and unburned petroleum and traffic emission could contribute the highest ECR (2.4 × 10−5). The CPF results show that directional apportionment patterns were consistent with the actual locations of local PAH sources. The PSCF results indicate that mainly northeastern regions of China have contributed elevated PM2.5-bound PAHs from long-range transports.

While the spatial distributions of heavy metals in farmland soil of China have been comprehensively delineated, their temporal trends are rarely investigated but are important for environmental risk management. In this study, the current status and temporal trends of heavy metals in the farmland soil of Yangtze River Delta (YRD) were evaluated through field survey and meta-analysis. The field survey conducted in 2014 showed that the concentrations of Cd, Pb, Cu, Zn, and Ni in the farmland topsoil were 0.23 ± 0.14, 37.63 ± 15.60, 25.83 ± 41.62, 88.38 ± 43.30, and 29.21 ± 12.41 mg kg−1 (mean ± standard deviation), respectively. The heavy metals showed relatively higher concentrations on the borders among Zhejiang, Jiangsu, and Shanghai. In the meta-analysis, we selected 68 published studies related to heavy metal pollution in farmland topsoil of YRD from 2000 to the year (2014) when the field survey was conducted. The results show an increasing trend for Cd (p < 0.05; 0.0081 mg kg−1 year−1), a decreasing trend for Cu (p < 0.05; -0.80 mg kg−1 year−1), and no significant trend for Pb (p = 0.155), Zn (p = 0.746), and Ni (p = 0.305). The increasing rate of Cd from the meta-analysis is consistent with the rate (0.0013 mg kg−1 year−1) derived from the mass balance calculation for Cd, where atmospheric deposition originated from intensive coal combustion is considered as the main source of Cd in the topsoil. The decreasing trend of Cu is likely due to largely reduced application of copper-based agrochemicals. Environmental regulation and soil remediation are needed to protect food safety and ecosystem from heavy metal pollution, especially Cd.

Polycyclic aromatic hydrocarbons (PAHs) were studied in 230 daily fine particulate matter (PM2.5) samples collected in four seasons at urban and suburban sites of Shanghai, China. This study focused on the emission sources of PAHs and its dynamic results under different weather conditions and pollution levels and also emphasized on the spatial sources of PM2.5 and PAHs at a regional level. Annual concentrations of PM2.5 and 16 EPA priority PAHs were 53 μg/m3 and 6.9 ng/m3, respectively, with highest levels in winter. Positive matrix factorization (PMF) modeling identified four sources of PAHs: coal combustion, traffic, volatilization and biomass combustion, and coking, with contributions of 34.9%, 27.5%, 21.1% and 16.5%, respectively. The contribution of traffic, a local-indicative source, increased from 17.4% to 28.7% when wind speed changed from >2m/s to <2m/s, and increased from 18.3% to 31.3% when daily PAH concentrations changed from below to above the annual mean values. This indicated that local sources may have larger contributions under stagnant weather when poorer dispersion conditions and lower wind speed led to the accumulation of local-emitted pollutants. The trajectory clustering and potential source contribution function (PSCF) and concentration weighted trajectory (CWT) models showed clearly that air parcels moved from west had highest concentrations of PM2.5, total PAHs and high molecular weight (HMW) PAHs. While small differences were found among all five clusters in low molecular weight (LMW) PAHs. Sector analyses determined that regional transport source contributed 39.8% to annual PM2.5 and 52.5% to PAHs, mainly from western regions and varying with seasons. This work may make contribution to a better understanding and control of the increasingly severe air pollution in China as well as other developing Asian countries.

To investigate the size distributions of chemical compositions and sources of particulate matter (PM) at ground level and from the urban canopy, a study was conducted on a 255 m meteorological tower in Tianjin from December 2013 to January 2014. Thirteen sets of 8 size-segregated particles were collected with cascade impactor at 10 m and 220 m. Twelve components of particles, including water-soluble inorganic ions and carbonaceous species, were analyzed and used to apportion the sources of PM with positive matrix factorization. Our results indicated that the concentrations, size distributions of chemical compositions and sources of PM at the urban canopy were affected by regional transport due to a stable layer approximately 200 m and higher wind speed at 220 m. The concentrations of PM, Cl− and elemental carbon (EC) in fine particles at 10 m were higher than that at 220 m, while the reverse was true for NO3− and SO42−. The concentrations of Na+, Ca2+, Mg2+, Cl− and EC in coarse particles at 10 m were higher than that at 220 m. The size distributions of major primary species, such as Cl−, Na+, Ca2+, Mg2+ and EC, were similar at two different heights, indicating that there were common and dominant sources. The peaks of SO42−, NH4+, NO3− and organic carbon (OC), which were partly secondary generated species, shifted slightly to the smaller particles at 220 m, indicating that there was a different formation mechanism. Industrial pollution and coal combustion, re-suspended dust and marine salt, traffic emissions and transport, and secondary inorganic aerosols were the major sources of PM at both heights. With the increase in vertical height, the influence of traffic emissions, re-suspended dust and biomass burning on PM weakened, but the characteristics of regional transport from Hebei Province and Beijing gradually become obvious.

Concentrations and isotopic compositions of Pb and Sr in the surface sediment samples from Jiulong River, Southeast China, were determined to trace the sources of Pb and Sr. The average concentrations of Pb and Sr were 110.9 mg/kg and 69.2 mg/kg, approximately 3.2 and 2.0 times of the local soil background values, respectively. Average 62.9% of total Pb and 36.8% of total Sr in the investigated surface sediment samples were extracted by 0.5 mol/L HNO3. Pb and Sr presented slight contamination, and Pb showed low ecological risk for most of surface sediment samples in Jiulong River according to geo-accumulation index (Igeo) and potential ecological risk index (RI). The results of Pb isotopic compositions in sediment samples and potential sources showed that the Pb accumulated in the surface sediments of Jiulong River was mainly from parent material, coal combustion and Fujian Pb-Zn deposit, with the contribution rates of 34.4%, 34.0%, and 31.6%, respectively. The results of Pb isotopic compositions in 0.5 mol/L HNO3-extraction suggested that dilute HNO3-extraction was more sensitive in identifying anthropogenic Pb sources than total digestion. The results of Sr isotopic compositions showed that Sr accumulated in the surface sediments of Jiulong River estuary mainly derived from external source and natural source (parent material) with the contribution rates of 48.1% and 51.9%, respectively.

Polycyclic aromatic hydrocarbons (PAHs) were assessed spatially and temporally within and adjacent to a former coking and steel manufacturing facility in Sydney, Nova Scotia, Canada. Concentrations of PAHs were measured in surface soils, marine and estuary sediments prior to and during remediation of the Sydney Tar Ponds (STPs) site which was contaminated by nearly a century of coking and steel production. Previous studies identified PAHs in surficial marine sediments within Sydney Harbour, which were considered to be derived from STP discharges. Numerous PAH fingerprint techniques (diagnostic ratios, principal component analysis, quantitative and qualitative analysis) were applied to soil and sediment samples from the STPs and surrounding area to identify common source apportionment of PAHs. Results indicate coal combustion (from historical residential, commercial and industrial uses) and coal handling (from historic on-site stockpiling and current coal transfer and shipment facilities) are likely the principal source of PAHs found in urban soils and marine sediments, consistent with current and historical activities near these sites. However, PAH fingerprints associated with STP sediments correlated poorly with those of urban soils and marine sediments, but were similar to coal tar, historically consistent with by-products produced by the former coking operations. This study suggests PAH contamination of Sydney Harbour sediments and urban soils is largely unrelated to historic coking operations or recent remediation of the STPs site, but rather a legacy of extensive use of coal for a variety of activities.

Heavy metals (Cr, Co, Ni, As, Cd, and Pb) can be bound to PM adversely affecting human health. Quantifying the source impacts on heavy metals can provide source-specific estimates of the heavy metal health risk (HMHR) to guide effective development of strategies to reduce such risks from exposure to heavy metals in PM2.5 (particulate matter (PM) with aerodynamic diameter less than or equal to 2.5 μm). In this study, a method combining Multilinear Engine 2 (ME2) and a risk assessment model is developed to more effectively quantify source contributions to HMHR, including heavy metal non-cancer risk (non-HMCR) and cancer risk (HMCR). The combined model (called ME2-HMHR) has two steps: step1, source contributions to heavy metals are estimated by employing the ME2 model; step2, the source contributions in step 1 are introduced into the risk assessment model to calculate the source contributions to HMHR. The approach was applied to Huzou, China and five significant sources were identified. Soil dust is the largest source of non-HMCR. For HMCR, the source contributions of soil dust, coal combustion, cement dust, vehicle, and secondary sources are 1.0 × 10−4, 3.7 × 10−5, 2.7 × 10−6, 1.6 × 10−6 and 1.9 × 10−9, respectively. The soil dust is the largest contributor to HMCR, being driven by the high impact of soil dust on PM2.5 and the abundance of heavy metals in soil dust.

From November 2014 to October 2015, the concentrations of volatile organic compounds (VOCs), O3 and NOx were simultaneously monitored by using online instruments at the air monitoring station belonged to Tianjin Environmental Protection Bureau (TEPB). The results indicated that VOCs concentrations were higher in autumn and lower in spring, while O3 concentrations were higher in summer, and lower in winter. The diurnal variations of VOCs and NOx (NO2 plus NO) showed opposite tendency comparing to that of O3. The concentrations of alkanes were higher (the average of 18.2 ppbv) than that of aromatics (5.3 ppbv) and alkenes (5.2 ppbv), however, the alkenes and aromatics made larger contributions to ozone because of their high reactivity. Tianjin belonged to the VOC-limited region during most of seasons (except summer) according to the VOC/NOx ratios (the 8:1 threshold). The automobile exhaust, industrial emission, liquefied petroleum gas/natural gas (LPG/NG), combustion, gasoline evaporation, internal combustion engine emission and solvent usage were identified as major sources of VOCs by Positive Matrix Factorization (PMF) model in Tianjin, and the contributions to VOCs for the entire year were 23.1%, 19.9%, 18.6%, 10.6%, 8.7%, 5.4% and 4.7%, respectively. The conditional probability function (CPF) analysis indicated that the contributing directions of automobile exhaust and industrial emission were mainly affected by source distributions, and that of other sources might be mainly affected by wind direction. The backward trajectory analysis indicated that the trajectory of air mass originated from Mongolia, which reflected the features of large-scale and long-distance air transport, and that of beginning in Jiangsu, Shandong and Tianjin, which showed the features of small-scale and short-distance. Tianjin, Beijing, Hebei and Northwest of Shandong were identified as major potential source-areas of VOCs by using potential source contribution function (PSCF) and concentration-weighted trajectory (CWT) models.

Little is known about the propensity of crocodilians to bioaccumulate trace elements as a result of chronic dietary exposure. We exposed 36 juvenile alligators (Alligator mississippiensis) to one of four dietary treatments that varied in the relative frequency of meals containing prey from coal combustion waste (CCW)-contaminated habitats vs. prey from uncontaminated sites, and evaluated tissue residues and growth rates after 12 mo and 25 mo of exposure. Hepatic and renal concentrations of arsenic (As), cadmium (Cd) and selenium (Se) varied significantly among dietary treatment groups in a dose-dependent manner and were higher in kidneys than in livers. Exposure period did not affect Se or As levels but Cd levels were significantly higher after 25 mo than 12 mo of exposure. Kidney As and Se levels were negatively correlated with body size but neither growth rates nor body condition varied significantly among dietary treatment groups. Our study is among the first to experimentally examine bioaccumulation of trace element contaminants in crocodilians as a result of chronic dietary exposure. A combination of field surveys and laboratory experiments will be required to understand the effects of different exposure scenarios on tissue residues, and ultimately link these concentrations with effects on individual health.