Preliminary characterization and source assessment of PAHs in tributary sediments of the Athabasca River,Canada

The Athabasca Oil Sands are one of four natural oil sands deposits in Northern Alberta, Canada. As a number of new mines are planned in the area, there is a need to establish background levels of natural hydrocarbon release prior to these developments. To this end, various environmental samples were taken from selected tributaries in the oil sands region of the Athabasca River Basin and analysed by gas chromatography/mass spectrometry (GC/MS) for polycyclic aromatic hydrocarbons (PAHs) and their alkylated analogues. Samples were collected over 3 years (1998–2000) to provide an increased understanding of the spatial distribution, nature and extent of natural hydrocarbon release to the environment. Results indicated that levels of total PAHs were elevated in the tributaries (up to 34·7 μg/g) compared to the main stem Athabasca River (<2 μg/g). As expected, samples from the oil sands deposits contained the greatest amounts of PAHs and alkylated PAHs. Profiles of the alkylated PAH distributions were very similar, indicating that all the samples tested were from a common petrogenic source.     

Structural and optical characterization of dissolved organic matter from the lower Athabasca River, Canada

Dissolved organic matter (DOM) is a ubiquitous constituent of natural waters and is comprised of a variety of chemically heterogeneous molecular structures and functional groups. DOM is often considered to be a major ligand for metals in most natural waters and its reactivity is thought to be strongly dependent on its chemical composition and structure. In this study, a combination of UV/visible, emission excitation matrix fluorescence (EEM) and ¹H NMR spectroscopies were used to characterize DOM from the Athabasca River (Alberta, Canada). The chemical characterization of river DOM showed that the most upstream samples located in agricultural areas were blue-shifted and less aromatic and contained more hydrogens connected with oxygen functional groups than those in the wetland dominated area in the Athabasca oil sand deposit region. The presence of paramagnetic ions (Fe and Al) was not found to significantly affect the structural composition of DOM as revealed by ¹H NMR. Such change in the quality of DOM may have a profound impact on metal binding in the Athabasca River watershed.     

Distribution,source, and ecological risk assessment of PAHs among size and density fractions in contaminated sediments from the Yellow River of Henan section

This study investigated particle size and density distributions of polycyclic aromatic hydrocarbons (PAHs) in two surface sediments (JZ and KF), collected from the Yellow River of Henan section, China. The concentrations of Σ₁₅PAHs ranged from 35.6 to 45862?ng g^?1 dry wt, which were greatly elevated in coarse particles and low-density fractions. The Σ₁₅PAHs concentrations in low-density fractions were 533 (JZ) and 996 (KF) times higher than those in the corresponding high-density fractions. However, due to relatively less quantities of low-density fractions (0.27–2.33%), most of the PAHs were contributed by the high-density components. For both sediments, the influence factors of PAHs source in the environment were very complex, more so than the level of TOC and BC content. JZ sediment was dominated by 4-ring to 6-ring PAHs (61.5–75.1%), while, 2-ring to 3-ring PAHs were abundant in KF samples (39.8–72.6%). Ratios of specific PAHs reflected PAHs among the size- and density-fraction of each sediment may be contaminated by mixed of pyrolytic and petrogenic origin. Additionally, ecological risk assessment of PAHs suggested that total toxic equivalent values of PAHs in the low-density fractions were much higher than those of the corresponding high-density fractions in the studied area.     

Concentration,sources and risk assessment of PAHs in bottom sediments

Environmental Science and Pollution Research - The aims of the study were to investigate the concentration, sources and ecological risk of PAHs (polycyclic aromatic hydrocarbons) in bottom...     

Spatial distribution,potential risk assessment,and source apportionment of polycyclic aromatic hydrocarbons (PAHs) in sediments of Lake Chaohu,China

Twenty-nine sediment samples were collected from Lake Chaohu, a shallow eutrophic lake in Eastern China, and were analyzed for 15 priority polycyclic aromatic hydrocarbons (PAHs) to determine the spatial distribution and exposure risks of PAHs. Three receptor models, the principal component analysis-multiple linear regression (PCA-MLR) model, the positive matrix factorization (PMF) model, and the Unmix model, were used in combination with the PAHs diagnostic ratios to investigate the potential source apportionment of PAHs. A clear gradient in the spatial distribution and the potential toxicity of PAHs was observed from west to east in the sediments of Lake Chaohu. ∑₁₅PAH concentrations and the TEQ were in the range of 80.82-30 365.01 ng g^?1 d.w. and 40.77-614.03, respectively. The highest values of the aforementioned variables were attributed to urban–industrial pollution sources in the west lake region, and the levels decreased away from the river inlets. The three different models yielded excellent correlation coefficients between the predicted and measured levels of the 15 PAH compounds. Similarly, source apportionment results were derived from the three receptor models and the PAH diagnostic ratios, suggesting that the highest contribution to the PAHs was from coal combustion and wood combustion, followed by vehicular emissions. The PMF model yielded the following contributions to the PAHs from gasoline combustion, diesel combustion, unburned petroleum emissions, and wood combustion: 34.49, 24.61, 16.11, 13.01, and 11.78 %, respectively. The PMF model produced more detailed source apportionment results for the PAHs than the PCA-MLR and Unmix models.     

Characteristics,source, and potential ecological risk assessment of polycyclic aromatic hydrocarbons (PAHs) in the Songhua River Basin,Northeast China

Environmental Science and Pollution Research - The concentration characteristics, sources, and potential ecological risk assessment of 16 PAHs were investigated in the surface water from the...     

Organochlorine pesticides and polychlorinated biphenyls in riverine runoff of the Pearl River Delta, China: assessment of mass loading, input source and environmental fate

A large-scale sampling program was conducted to simultaneously collect water samples at the eight major riverine runoff outlets of the Pearl River Delta (PRD), South China to assess the importance of riverine runoff in transporting anthropogenic pollutants from terrestrial sources to the coastal ocean. The concentrations of ∑₂₁OCPs (sum of 21 OCP components) and ∑₂₀PCBs (sum of 20 PCB congeners) were 2.57-41.2 and 0.12-1.47 ng/L, respectively. Compositional distributions of DDTs suggested the possibility of new input sources in the study area, but contributions from dicofol seemed considerably low. The annual inputs of ∑₂₁OCPs and ∑₂₀PCBs were 3090 and 215 kg, with those of total HCHs and DDTs being 1110 and 1020 kg, respectively. A mass balance consideration indicated that riverine runoff is the major mode carrying OCPs from the PRD to the coastal ocean, and the majority of OCPs is further dissipated to open seas.     

Environmental distribution of PAHs in pine needles,soils, and sediments

Introduction  

The content of 16 polycyclic aromatic hydrocarbons (PAHs) was determined in 60 samples from three environmental matrices (soils, sediments, and pine needles) in an effort to assess their distribution on a river basin scale.     

Environmental assessment of polycyclic aromatic hydrocarbons (PAHs) in surface sediments of the Santander Bay,Northern Spain

Samples of intertidal surface sediments (0-2 cm) were collected in 17 stations of the Santander Bay, Cantabric Sea, Northern Spain. The concentrations of polycyclic aromatic hydrocarbons (PAHs), 16, were analysed by HPLC and MS detection. Surface sediments show a good linear correlation among the parameters of the experimental organic matter evaluation, where total carbon (TC) and loss on ignition (LOI) are approximately 2.5 and 5 times total organic carbon (TOC). A wide range of TOC from 0.08% to 4.1%, and a broad distribution of the sum of sigma16PAHs, from 0.02 to 344.6 microg/g d.w., which can be correlated by an exponential equation to the TOC, has been identified. A qualitative relationship may be established between the industrial input along the rivers and the concentration of sigma6PAHs in the sediments of the estuaries: Boo estuary (8404-4631 microg/g OC), Solia-San Salvador estuaries (305-113 microg/g OC) and Cubas estuary (31-32 microg/g OC). This work shows a dramatic change in the spatial distribution in the concentration of PAHs of intertidal surface sediments. The left edge of the Bay has the main traffic around the city and the major source of PAHs is from combustion processes and estuarine inputs, leading to medium values of PAHs in the sediments; the right edge of the Bay has much lesser anthropogenic activities leading to lower values of PAHs in sediments. The distribution of individual PAHs in sediments varies widely depending on their structure and molecular weight; the 4-6 ring aromatics predominate in polluted sediments due to their higher persistence. The isomer ratio does not allow any clear identification of the PAHs origin. Environmental evaluation according to Dutch guidelines and consensus sediment quality guidelines based on ecotoxicological data leads to the same conclusion, sediments in the Santander Bay show a very different environmental quality depending on the spatial position from heavily polluted/medium effects to non-polluted/below threshold effects. These results indicate that local sources of PAHs, especially estuary discharges, lead to very different qualities of sediments in coastal zones, where traffic and industrial activities take place.     

Characterization, sources, and potential risk assessment of PAHs in surface sediments from nearshore and farther shore zones of the Yangtze estuary, China

The assessment of polycyclic aromatic hydrocarbons (PAHs) contamination in surface sediments from the Yangtze estuary which is a representative area affected by anthropogenic activity (rapid industrialization, high-population density, and construction of dams upstream) in the world was systematically conducted. Fifty-one samples were analyzed by high-performance liquid chromatography (HPLC). The ??PAHs in all sediments varied from 76.9 to 2,936.8?ng?g^?1. Compared with other estuaries in the world, the PAH levels in the Yangtze estuary are low to moderate. Phenanthrene, acenaphthylene, fluoranthene, and pyrene were relatively abundant. The ??PAH levels and composition varied obviously in different estuarine zones due to different sources. The highest ??PAHs concentration was observed in the nearshore of Chongming Island. The PAH composition showed that four to six ring PAHs were mainly found in the nearshore areas, while two to three ring PAHs were in the farther shore zones. The PAHs in the Yangtze estuary were derived primarily from combustion sources. A mixture of petroleum combustion and biomass combustion mainly from coal combustion and vehicle emission was the main source of PAHs from the nearshore areas, while the spill, volatilization, or combustion of petroleum from shipping process and shoreside discharge were important for PAHs in the farther shore areas. The result of potential ecotoxicological risk assessment based on sediment quality guidelines indicated low PAH ecological risk in the Yangtze estuary. The study could provide foundation for the protection of water quality of the Yangtze estuary by inducing main sources input.     

Plateau River research: ecological risk assessment of surface sediments in the Yarlung Tsangpo River

Environmental Science and Pollution Research - To fully understand the environmental quality of sediments in the Yarlung Tsangpo River Basin, surface sediments of the mainstream of the Yarlung...     

Pollution characteristics and potential ecological risk assessment of metals in the sediments of Xiaoqing River,Jinan

Environmental Science and Pollution Research - The spatial–temporal changing characteristics and potential ecological risk combined with local policies and industrial status were analyzed....     

Pt and Pd in sediments from the Pearl River Estuary,South China: background levels,distribution, and source

Purpose  

This study assessed the concentrations of platinum (Pt) and palladium (Pd) in surface sediments and sedimentary cores collected from the Pearl River Estuary with a view of evaluating the distribution, background levels, possible sources, and contamination level of anthropogenic Pt and Pd.     

Heavy metal in sediments of Ziya River in northern China: distribution,potential risks,and source apportionment

The concentration partitioning between the sediment particle and the interstitial water phase plays an important role in controlling the toxicity of heavy metals in aquatic systems. The aim of this study was to assess the sediment quality in a polluted area of the Ziya River, Northern China. The contamination potential and bioavailability of six metals were determined from the concentrations of total metals and the bioavailable fractions. The results showed that the concentrations of Cr, Cu, Ni, Zn, and Pb exceeded the probable effect concentration at several sites. The high geoaccumulation indices showed that the sediments were seriously contaminated by Cd. The ratio of acid-volatile sulfide (AVS) to simultaneously extracted metal (SEM) was higher than 1, which indicated that the availability of metals in sediments was low. The risk assessment of interstitial waters confirmed that there was little chance of release of metals associated with acid-volatile sulfide into the water column. Values of the interstitial water criteria toxicity unit indicated that none of the concentrations of the studied metals exceeded the corresponding water quality thresholds of the US Environmental Protection Agency. Positive matrix factorization showed that the major sources of metals were related to anthropogenic activities. Further, if assessments are based on total heavy metal concentrations, the toxicity of heavy metals in sediment may be overestimated.     

南苕溪支流锦溪水质时空变化特征分析

综合运用灰色聚类法、综合污染指数法、等级聚类法就南苕溪支流锦溪近年水质时空变化特征进行分析。结果表明,锦溪入青山水库断面水质2005—2009年逐年改善,2007年后达到灰色聚类等级Ⅲ类水质要求;2009年秋季至2010年夏季期间秋、冬两季的污染程度高于春、夏季节;枯水期综合污染指数最高,但TN、TP污染分指数在丰水期最高,表明污染源中面源污染已占相当比例。空间变化方面从玲珑桥到江桥锦溪水质的综合污染指数不断提升,到江桥时达到极值13.25,锦溪末端三眼桥断面水质较江桥断面有所改善;SPSS空间聚类分析可分为轻污染区(从玲珑桥到冬韵桥)、重污染区(从群利桥到江桥)和中度污染区(从江桥到三眼桥)。锦溪上游农业区对河水中的COD、TN和TP的贡献率分别为66%、54%和49%,农业面源污染已成为制约锦溪水质改善的主要因素。     

Fate of linear alkylbenzenes and benzothiazoles of anthropogenic origin and their potential as environmental molecular markers in the Pearl River Delta, South China

The mass emissions of linear alkylbenzenes (LABs), benzothiazole (BT), and 2-[4-morpholinyl]benzothiazole (24MoBT) from anthropogenic activities within one year were estimated according to the population and the number of automobiles in the Pearl River Delta (PRD), South China. Based on the estimation, the distribution of these compounds among various environmental media was simulated with a mass balance box model established in the present study. The results showed that 79% of LABs generated in the PRD was stored in sediment while only 1.3% of LABs was presumably transported to the adjacent South China Sea (SCS). On the contrary, 47% of BT and 77% of 24MoBT generated in the region were carried with riverine runoff to the coastal ocean. The results from the present study suggest that hydrophobic compounds tend to stay in the watershed of the PRD, whereas hydrophilic ones mainly outflow to the coastal ocean.     

长江、嘉陵江(重庆段)源水有机提取物的类雌激素活性评价

为了解长江、嘉陵江(重庆段)源水有机提取物的类雌激素活性，分别于夏季和冬季采用GDX—120大孔树脂对位于城区上、中、下游5个断面长江、嘉陵江(重庆段)源水进行有机物的浓缩提取。用体外MCF—7细胞增殖试验检测有机提取物的类雌激素活性。结果显示，源水有机提取物均具有类雌激素活性。其类雌激素活性中、下游均高于上游，丰水期高于枯水期。     

Potential source apportionment of polycyclic aromatic hydrocarbons in surface sediments from the middle and lower reaches of the Yellow River,China

In this work, principal component analysis/multiple linear regression (PCA/MLR), positive matrix factorization (PMF), and UNMIX model were employed to apportion potential sources of polycyclic aromatic hydrocarbons (PAHs) in surface sediments from middle and lower reaches of the Yellow River, based on the measured PAHs concentrations in sediments collected from 22 sites in November 2005. The results suggested that pyrogenic sources were major sources of PAHs. Further analysis indicated that source contributions of PAHs compared well among PCA/MLR, PMF, and UNMIX. Vehicles contributed 25.1–36.7 %, coal 34.0–41.6 %, and biomass burning and coke oven 29.2–33.2 % of the total PAHs, respectively. Coal combustion and traffic-related pollution contributed approximately 70 % of anthropogenic PAHs to sediments, which demonstrated that energy consumption was a predominant factor of PAH pollution in middle and lower reaches of the Yellow River. In addition, the distributions of contribution for each identified source category were studied, which showed similar distributed patterns for each source category among the sampling sites.     

黄河干流表层沉积物中重金属形态分析与风险评价

对黄河全流域表层沉积物样品中重金属元素 (As、Cd、Cr、Cu、Ni、Pb、Zn、V、Co) 的赋存形态进行分析,发现Cd的可利用态占比较高,其余重金属以残渣态为主。基于可利用态重金属含量计算重金属风险评价标准、次生相和原生相分布比值,从而对表层沉积物中重金属的生态风险进行评估。结果表明,整个流域中Cd的生态风险最高。此外,Cd和Pb等重金属在M6点位迁移性较高,存在一定的生态风险。对可利用态重金属进行人体健康风险评价,发现M6点位儿童的致癌 (8.76×10⁻⁶) 和非致癌风险总值 (0.32) 最高。成人与儿童非致癌健康风险总值中As的贡献率最大 (61.28%和62.71%) ,致癌健康风险总值中As的贡献率也最大 (75.91%和75.98%) ,但总体均未超过美国环境总署推荐的人体最大可接受范围。本研究可为识别黄河干流表层沉积物中重金属风险及制定相应污染防控策略提供参考。