Polycyclic aromatic hydrocarbons in farmland soils around main reservoirs of Jilin Province,China: occurrence,sources and potential human health risk

Study on the occurrence, sources and potential human health risk of polycyclic aromatic hydrocarbons in farmland soils around reservoirs is of great significance for the people drinking water security. In the present study, representative farmland soil samples around main reservoirs of Jilin Province, China, were investigated for 16 PAHs. The total concentrations of 16 priority PAHs in 32 farmland soil samples ranged from 602.12 to 1271.87 ng/g, with an arithmetic average of 877.23 ng/g, and the sum of seven carcinogenic PAH concentrations ranged from 30.07 to 710.02 ng/g, with a mean value of 229.04 ng/g. The 3-ring and 4-ring PAHs were major exist and account for 45.78 and 32.03%, respectively. Non-cancer and cancer risk of pollutants were calculated, and the results indicate that the complex PAHs in farmland soils were not considered to pose significant health effects. The isomer ratios Fla/(Fla + Pyr) and BaA/(BaA + Chr) show that the PAHs in soils were generally derived from biomass and coal combustion.     

Risk assessment of human exposure to polycyclic aromatic hydrocarbons via shrimp (<Emphasis Type="Italic">Macrobrachium felicinum</Emphasis>) consumption along the Imo River catchments,SE Nigeria

Shrimp species (Macrobrachium felicinum) collected from estuarine mangrove area of the Imo River is an important route of exposure to polycyclic aromatic hydrocarbons (PAHs). The estuarine associated sediment (EAS) composited sample showed higher TPAH, ΣAlkyl, ΣPAH_carc and ΣPAH_EPA concentrations (550.84, 172.36, 413.17 and 482.11 ng/g dry weight—dw) than their mean concentrations in shrimp samples (509.39 ± 354.21, 31.38 ± 18.49, 52.10 ± 1.35 and 460.06 ± 330.76 ng/g wet weight—ww), respectively. Among the individual PAHs congeners, phenanthrene was the dominant species detected in the EAS accounting for 21.02 % of the total PAH load and the decreasing order of 3- > 2- > 5- > 4- > 6-ring contamination was found. A different pattern predominated by naphthalene was observed for the shrimp species, suggesting that the organisms have different selectivity for a range of PAHs congeners. These variations may be attributed to different degree of bioavailability of these compounds, characteristic sandy lithology of the EAS and the protective capacity of soot particles associated with liquid fossil fuel combustion masking the uptake of high molecular weight PAHs by the organisms. Cancer risk associated with consumption of shrimps in the region was assessed using estimated daily intake (EDI) and compared with standards. The EDI values for naphthalene, benzo(a)pyrene and ∑PAH_carc were lower than the USEPA benchmarks and EFSA levels of concern values for adult and children population, suggesting low probability of developing cancer.     

汕头经济特区土壤中优控多环芳烃的分布

运用气相色谱-质谱方法对汕头经济特区131个土样中的美国EPA优控多环芳烃(PAHs)进行定性、定量测定,讨论了PAHs的分布特征。结果表明,该区表层土壤中优控PAHs的总质量分数范围从22.1 ng/g到1256.9 ng/g之间,平均质量分数为(317.3210.2) ng/g。其分布随采样点的位置不同而有显著变化:工业区附近多环芳烃的质量分数最高,城市中心次之,郊区最低。大多数样点中?PAHs质量分数和单种PAH质量分数都呈现w(5~20 cm)> w(0~5 cm)>w(20~40 cm)>w(40~100 cm)的垂直分布规律。该区土壤PAHs以3环和4环化合物为主,单种PAH以萘、菲和苯并[b]萤蒽为主。     

PAH depositional history and sources in recent sediment core from Ukwa Ibom Lake, S. E. Nigeria

Analyses of recent sediment core from the Ukwa Ibom Lake show evidence of aquatic production, terrigenous, combustion and petroleum inputs. Total organic carbon/total nitrogen values (>10) for the sediments indicate greater wash-in of land-plant organic matter relative to algal production. The characteristic combustion ratios, fluoranthene/fluoranthene + pyrene (>0.50), anthracene/anthracene + phenanthrene (>0.10), benzo(a)anthracene/benzo(a)anthracene + chrysene (>0.35) as well as 1,7/1,7 + 2,6-dimethylphenanthrene (>0.70) were observed for the top section only. These results coincided with the most recent pave-road extension exercise involving tree logging and burning of bush. The highest total PAH concentration (91.13 ng/g dry weight (dw)) observed for the bottom section coincided with the period of inhabitation of the lake catchments (~5 decades ago) when discharge to the Lake water of domestic sewage and mill waste water were prevalent. The regular decline in total PAH concentrations upcore is a reflection of the ban placed on indiscriminate dumping of wastes following relocation of the inhabitants of the catchments. Besides the local depositional history, the irregular decrease in unresolved complex mixture (UCM) profiles suggests regional contaminant influx from the adjacent upper Cross River estuary, especially during intense rainfall event. The non-uniformity in methylphenanthrene indices (MPI-1 and MPI-2) shows evidence of importation and utilization of petroleum products of different thermal maturity histories into the Nigerian economy.     

Historical record of anthropogenic polycyclic aromatic hydrocarbons in a lake sediment from the southern Tibetan Plateau

High-altitude lake sediments can be used as natural archives to reconstruct the history of pollutants. In this work, the temporal distribution of polycyclic aromatic hydrocarbons (PAHs) was determined in a sediment core collected from the southern Tibetan Plateau (TP), which was dated by using the ²¹⁰Pb dating method and validated with the ¹³⁷Cs fallout peak. The concentrations of the anthropogenic PAHs (Σ₈PAH) in the sediment core ranged from 0.83 to 12 ng/g dw, and the fluxes of the Σ₈PAH were in the range of 2.1–27 g/cm²/year. The temporal variations in the concentration and input flux of anthropogenic PAHs were low with little variability before the 1950s, and then gradually increased from the 1950s to the 1980s, and an accelerated increase was observed after the early 1980s. The content of total organic carbon played an insignificant role in affecting the time trends of PAHs in the sediment core. Diagnostic concentration fractions of PAH components indicate PAHs in the lake sediment of the southern TP which are mainly from biomass burning and/or from long-range atmospheric transport.     

北京城市道路积尘中多环芳烃的分布特征

从2006年4月至2007年7月,对北京市不同类型道路的路面积尘进行了16个月的连续采样和分析,结果显示,交通道路路面积尘的3种粒径中∑16PAHs范围为123.71～18489.5ng/g,其16个月的几何均值为2378.28～4834.68ng/g,其中以3、4环为主。冬春季路面积尘中的多环芳烃含量高于夏秋季;交通道路路面积尘中的多环芳烃含量均比对照点高,不同类型的道路也呈现出差异,在同一条道路的机动车道、自行车道和人行道也表现出显著的差异。     

珠江水体表层沉积物中PAHs的含量与来源研究

沿珠江白鹅潭水域及大学城官州河流域设立6个采样点,利用沉积物捕获器收集沉积物。参照美国EPA8000系列方法及质量保证和质量控制,对各采样点表层沉积物中16种多环芳烃（polycyclic aromatic hydrocarbons,PAHs）进行分析,以阐明珠江广州河段表层沉积物中PAHs的含量和分布特征,并结合特征化合物指数对其来源作初步探讨。珠江广州河段表层沉积物中PAHs总量介于4 787.5～8 665 ng·g^-1,平均值为7 078 ng·g^-1,黄沙码头河涌出口沉积物中总量为最高（8 665 ng·g^-1）,芳村码头为最低（4 787.5 ng·g^-1）。16种多环芳烃中菲、荧蒽、芘含量较高,分别占PAHs总量的16.11%、14.47%和17.77%。特征化合物荧蒽/202比值均小于0.5,茚并[1,2,3-cd]芘/276比值均大于0.2,表明珠江广州段表层沉积物中PAHs主要来源于化石燃料的不完全燃烧。     

Polycyclic aromatic hydrocarbons in soils around Guanting Reservoir,Beijing, China

The concentrations of 16 polycyclic aromatic hydrocarbons (∑ 16PAHs) were measured by gas chromatography equipped with a mass spectrometry detector (GC-MS) in 56 topsoil samples around Guanting Reservior (GTR), which is an important water source for Beijing. Low to medium levels of PAH contamination (mean=394.2±580.7 ng g^?1 dry weight (d.w.)) was evident throughout the region. In addition, localised areas of high PAH contamination near steel and cement factories were identified, with ∑ 16PAHs concentrations as high as 4110 ng/g, dry weight (d.w.). There was a significant positive correlation (r²=0.570, p<0.01) between total organic carbon content and ∑ 16PAHs concentrations. Phenanthrene was the predominant compound, accounting for 27.2% of the ∑ PAH concentration, followed by chrysene>pyrene>benzo[a]anthracene≈ benzo[b]fluoranthene≈ benzo[a]pyrene. Four-ring PAH homologues (39%) were dominant. The higher proportion of 4–6 ring homologues, molecular indices, and the spatial distribution of PAH indicated that industrial discharges, incineration of wastes and traffic discharges were the major sources of soil PAHs around the water reservoir.     

Ecological risks of polycyclic aromatic hydrocarbons found in coastal sediments along the northern shores of the Bohai Sea (China)

The total concentrations of 16 United States Environmental Protection Agency (US EPA)-listed polycyclic aromatic hydrocarbons (PAHs) found in coastal and estuarine sediments along the northern shores of the Bohai and Yellow Seas, China, at any study location varied from 0.236 to 8.34 nM g^?1 dry weight (dw). For a given PAH, concentrations varied by one to two orders of magnitude. Ecological risk assessments based on biota–sediment accumulation factors (BSAFs) indicated that the potential ecological hazard of PAHs in the sediments was limited. The average total sediment PAH concentrations were less than the effects range low, indicating that PAHs currently present in the sediments were not harmful to aquatic organisms. The estimated PAH concentration in the aquatic organisms was 0.223 nM g^?1 and posed a limited threat to human health via biological concentration from sediment to harvest of the sea. Assuming no additional PAH inputs, 99% of the 16 PAH molecules currently present in the sediments would be degraded in 40 years.     

Biologic risk and source diagnose of 16 PAHs from Haihe River Basin,China

Surface sediments of rivers can exhibit spatial and temporal variations in contaminant concentrations that may significantly affect risk evaluations. As to pollution control and remediation of watershed, large-scale and further background data on PAHs in China were required urgently. Spatial distribution and compositional characteristics of 16 polycyclic aromatic hydrocarbons (PAHs) in surface sediments from Haihe River Basin were investigated. A method based on effects range (ER) was used to assess ecosystem risk of ∑PAHs (the total of 16 PAH) sensitively and accurately. The results indicated that ∑PAHs content levels ranged from 257 to 16901 μg·kg⁻¹ dry weight. The lower rings predominated in the samples, and 2-, 3-, 4-, 5- and 6-ring PAHs accounted for 12%, 21%, 30%, 30%, and 7% respectively in total PAHs. The ratio of Fl / (Fl+ Py) uniformly distributed in the interval 0.20–0.80, indicating that it may be affected by petroleum origin, oil combustion, biomass and coal combustion jointly. ∑PAHs in Cetian (S6), Dongwushi (S19), Handan (S20), Aixinzhuang (S21) and Tianjin (S37) exceeded effects range low (ERL), in which biologic effects were in a medium level with an adverse effect on biologic organisms. Thus, it is necessary to strengthen the PAHs monitoring and research of the Haihe River Basin.     

Assessment of PAHs in water and fish tissues from Great Bitter and El Temsah lakes,Suez Canal,as chemical markers of pollution sources

Sea water and fish tissue samples were collected from nine sampling stations from the Great Bitter and El Temsah lakes in the Suez Canal and analysed for polycyclic aromatic hydrocarbon (PAH). The compositions of PAH determined in the dissolved fraction of sea water were measured in order to use them as chemical markers for identifying different sources of PAH pollution in this region. PAHs determined in fish tissues were measured for comparison with human health standards as consumption. The total mean PAHs concentrations in the sea water samples ranged from 0.28 to 39.57 μg l^?1 with an overall mean of 10.78 and 12.38 μg l^?1 for El Temsah and Bitter Lakes water, respectively. Total PAHs fractions recorded in muscle tissues of all different Osteicthyes fishes collected from Great Bitter lakes ranged from 5.8 to 218.5 μg g^?1 with an overall mean of 57.98 μg g^?1 during all seasons. However, they ranged from 68 to 623 μg g^?1 with an overall mean of 87.69 μg g^?1 recorded in El Temsah lake during four seasons (2003–2004). Benzo(a)pyrene was the most dominant PAHs found in the sea water samples from both lakes with an average concentration of 3.8 μ g l^?1. Dibenzo(a,h)anthracene (DBA) was the most dominant PAHs recorded in fish samples. A maximum of 533 μg g^?1 of DBA was recorded in Dahbana sp. collected from Bitter lakes during January 2004. However, a maximum of 68.7 μ g g^?1 was recorded in Liza carinata species collected from El Temsah lake during July, 2004. The simultaneous occurrence of isomer ratios PHE/ANT<10 for all stations indicated that the major PAH input to water was from combustion of fossil fuel (pyrolytic source). The average ratios were 1.21 and 12.9 during winter (January 2004) and 4.3 and 8.63 during spring (April 2004) for all water samples of Great Bitter lakes and El Temsah lake, respectively. In addition, the present data demonstrate that PAHs from fossil fuel sources (MW<178) were the least significant source of PAHs in this region.     

Sources of polycyclic aromatic hydrocarbons (PAHs) in sediments of the Biobio River in south central Chile

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the environment; there are concerns about them due to their toxic properties. Human activities could significantly contribute to the total PAH burden in river sediments. In this work, we document the analysis of PAHs in sediments taken in the middle stretch of the Biobio River in south central Chile. This river is a principal system, draining more than 24,000 km² and subjected to a diverse variety of human-made stressors (pulp mill and urban effluents, agricultural drainage systems, etc). During 2003, several sediment samples were taken in more than 45 sampling sites located in the river’s middle stretch. Due to the granulometric characteristics (mainly sandy sediments), only 17 samples were analyzed, taking into consideration the presence of a fine section within the sediment sample. Using HPLC with fluorescence detection, 15 EPA priority PAHs and perylene were analyzed. The composition of PAHs in the sediment samples is rather similar between sites and levels averaged 104 ± 78 ng g⁻¹ d.w. The highest levels were detected downstream from an industrial discharge. A good correlation was observed between PAH levels and organic carbon content in the tested sediments; however, concentrations above 134 ng g⁻¹ d.w. did not indicate correlation. The samples PAH ratios (Flu/Pyr and Chr/B(a)A) reveal a strong pyrolytic PAH pattern in the sediments tested, supporting evidence indicating that PAHs come mainly from pyrolytic sources. This result contrasts with previous records that have shown a natural influence in the upper basin and a petrogenic pattern near the mouth.     

杭州市多环芳烃的干、湿沉降

多环芳烃（PAHs）是一类典型的持久性有机物,在各种环境介质广泛存在。为了研究干湿沉降对空气中PAHs的去除,采集了杭州市6个干沉降尘土样品、9个湿沉降雨水样品、5个湿沉降雪样品和6个地表径流样品,用高效液相色谱法（HPLC）测定了其中15种多环芳烃的浓度水平,比较了这些介质中PAHs的分布特点。结果表明,降尘中15种PAHs的总平均质量分数为4323ng·g^-1;雨水、雪水和地表径流样品中15种PAHs的总平均质量浓度分别为558.4ng·L^-1、765.1ng·L^-1和576.3ng·L^-1。地表径流、雨水、雪水和干沉降尘土4种样品中,都以4环PAHs为主,其次为3环PAHs。降雪比降雨对PAHs的去除效果更好,地表径流中PAHs主要来自雨水。根据杭州市大气降尘通量和降雨量,估算了PAHs的干湿沉降通量。杭州市辖区大气中每年PAHs的干湿沉降通量分别为1419.1kg和2689.8kg,湿沉降是PAHs去除的主要方式,约为干沉降去除总量的2倍。     

Polycyclic aromatic hydrocarbons and organochlorine pesticides in rice hull from a typical e-waste recycling area in southeast China: temporal trend, source, and exposure assessment

The residue levels of 16 US EPA priority polycyclic aromatic hydrocarbons (PAHs) and 16 selected organochlorine pesticides (OCPs) in rice and rice hull collected from a typical e-waste recycling area in southeast China were investigated from 2005 to 2007. PAHs and OCPs also were measured in ten mollusk species (soft tissues) collected in an adjacent bay in 2007. Individual PAHs were frequently found in the entire sample set (including the rice, hull, and mollusk samples) with a detection rate of 73 %. The total concentrations of 16 PAHs (ΣPAHs) and 16 OCPs (ΣOCPs) were in the range of 40.8–432 ng/g dry weight (mean: 171 ng/g) and 2.35–925 ng/g (122 ng/g), respectively, which were comparable or higher than those reported in some polluted areas. Statistical comparisons suggested that the concentrations of contaminants in hull gradually decreased from 2005 to 2007 and the residue levels were generally in the order of mollusk, hull, and rice, on a dry weight basis. Principal component analysis in combination with diagnostic ratios implied that combustion of coal, wood, and plastic wastes that are closely associated with crude e-waste recycling activities is the main source of PAHs. The finding of decreasing trend of concentrations of PAHs in this area is consistent with the efforts of local authorities to strengthen regulations on illegal e-waste recycling activities. Composition analysis suggested that there is a recent usage or discharge of hexachlorocyclohexane and dichlorodiphenyltrichloroethane into the tested area. The estimated daily intake (EDI) of ΣPAHs and ΣOCPs (calculated from mean concentrations) through rice and mollusk consumption was 0.411 and 0.921 μg/kg body weight (bw)/day, respectively.     

Hydrocarbons contamination and microbial degradation in mangrove sediments of the Niger Delta region (Nigeria)

The distribution of aliphatic hydrocarbons and polycyclic aromatic hydrocarbons (PAHs), and their degradability by bacteria in epipelic and benthic sediments from Qua Iboe Estuary mangrove ecosystem and associated creeks were investigated. The research findings revealed that total aliphatic hydrocarbons in sediments ranged from 16.82 mg·kg ^?1 to 210 mg kg ^?1, wheras total PAHs ranged from 6.30 to 35.55 mg·kg ^?1 dry weight of sediment. Low molecular mass (i.e. the 2–3-ring) PAHs were predominant in almost all the sampling points, whereas the higher molecular masses (4-, 5- and 6-ring PAHs) had the lowest concentrations. In general, the sediment samples ES ₂ (39.7%), ES ₃ (24.8%), BS ₁ (46.7%), BS ₂ (49.9%) and BS ₃ (44.2%) showed<50% contributions of Σ combustion–derived PAH (COMP-PAH) concentration to the Σ PAH concentrations, whereas ES ₁ (57%) contained>50% of COMP-PAHs. Our results have also shown that many mangrove bacteria have strong capacity to utilise Qua Iboe Light (QL) crude oil as the sole source of carbon and energy, while lower number of bacterial species including Bacillus sp., Micrococcus sp., Pseudomonas aeruginosa, Alcaligenes sp. and Flavobacterium sp. exhibited detectable PAHs degradability; and as such may serve as efficient degraders of QL crude oil contamination of mangrove ecosystem.     

Spatial and seasonal variation of polychlorinated biphenyls in Songhua River, China

The spatial and seasonal variation of polychlorinated biphenyls (PCBs) were investigated in water and sediment samples collected from Songhua River, China, from 2007 to 2008. The total concentration of PCB congeners ranged from 1.1 to 14 ng/l in water and 0.26–9.7 ng/g dry weight (dw) in sediment. The results of seasonal variation may suggest an impact to PCB concentration in water from its atmospheric input, the dilution to PCBs concentrations of high stream in summer, and a general trend towards increased volatilization in warmer conditions. From PCBs concentrations comparison between upstream and downstream of industrial urban cities, it was obvious that industrial urban cities reflect an important pollutant source for PCBs in our study, also with the evidences of high concentrations of PCBs occurring in high development industry and residential areas. Meanwhile, the homologue profile of PCBs in Songhua was analyzed, whose comparison with published data indicates that the sources of PCBs accumulated in the sediment may also came from the residue of PCBs production in China. Total five dioxin-like PCBs (CB-77, 81, 105, 114, and 126) and nine (CB-77, 81, 105, 114, 118, 123, 126, 156, and 167) were found in Songhua water and sediment.     

PAHs in surface sediments from coastal and estuarine areas of the northern Bohai and Yellow Seas, China

Polycyclic aromatic hydrocarbon (PAH) concentrations and their risks in surface sediments (n = 35) collected from coastal and estuarine areas of the northern Bohai and Yellow Seas, China, were investigated in 2008. Total concentrations of PAHs ranged from 52.3 to 1,870.6 ng/g dry weight. The greatest concentrations were observed in the Dou River of Tangshan where waste water from small factories is discharged into the river without treatment. At other locations, municipal sewage was the primary contributor of PAHs. Regional differences in concentrations of PAHs in sediments are related to human activities. Concentrations of PAHs were significantly correlated with concentrations of organic carbon in sediments. The patterns of relative concentrations and types of PAHs observed and knowledge of the potential sources, as well as the results of a principal component analysis, are consistent with the primary sources of PAHs in sediments of the northern Bohai Sea and Yellow Sea, being derived from the high-temperature pyrolytic processes such as combustion of fossil fuel. While concentrations of PAHs at most locations did not exceed the effects range median stated by the numerical effect-based sediment quality guidelines of the United States, concentrations of PAHs at some locations were similar to or greater than the effects range low.     

汾河流域水系和表层沉积物中多环芳烃的空间变化规律及其生态风险研究

本研究在汾河流域上、中、下游及其部分支流布设29个采样点,对其水体和表层沉积物多环芳烃(PAHs)的空间分布规律及生态风险进行了分析和讨论。结果表明,汾河流域水相中丰水期PAHs总量浓度范围是0.530~16.002μg·L~(-1),平均浓度为(2.738±3.078)μg·L~(-1),枯水期PAHs总量浓度范围是0.588~12.916μg·L~(-1),均值为(2.762±3.132)μg·L~(-1)。就空间分布而言,汾河流域整体呈现上游污染较轻,中下游污染严重的特点。PAHs的组成规律显示,丰水期和枯水期PAHs含量均以低环(2~3环)为主,不同采样期低环PAHs所占比例分别为96.5%和90.4%。与其他15个研究地区水体PAHs含量比较,汾河流域水体中PAHs污染程度的国内外对比处于中等到较高程度的污染。丰水期和枯水期水体中PAHs来源于石油源和植物、木材、煤的燃烧,主要受到流域煤化工、燃煤电厂排放污染物的影响。地表水健康风险评价结果显示,汾河流域丰水期和枯水期分别有13.8%和20.7%的点位存在一定的健康风险。汾河流域沉积相中16种PAHs平均浓度为(3.774±1.987)μg·g-1,其污染主要集中在流域中下游地区。PAHs的组成规律显示,PAHs含量集中在低环(2~3环),约占总量的75%左右。与本研究提到的河流、湖泊及港口沉积物中PAHs含量比较,汾河流域沉积物中PAHs污染程度仍处于中等偏高的污染水平。丰水期沉积相中PAHs以燃烧源和石油源为主,部分来自典型石油类产品的输入。表层沉积物生态风险评价结果显示,对于提出的12种PAHs的生态风险的效应区间低值(ERL值)或效应区间中值(ERM值)以及苯并(b)荧蒽(Bb F)和苯并(k)荧蒽(Bk F)这2类没有最低安全值的PAHs化合物来说,汾河上、中、下游流域均有采样点的PAHs可能存在着对生物的潜在生态风险。通过本研究可全面地了解该流域多环芳烃的空间分布规律及其可能的来源,并且为汾河流域多环芳烃污染的控制和生态风险评价提供科学依据。     

Aliphatic and polycyclic aromatic hydrocarbon contamination in surface sediment of the Chitrapuzha River,South West India

Distribution (seasonal and spatial) of aliphatic and polycyclic aromatic hydrocarbons (PAHs) in surface sediments of the Chitrapuzha River, Cochin, India, was investigated using gas chromatography. Significantly high concentrations prevailed during the pre-monsoon season with the industrial zones of the river appearing to be hot spots with particularly elevated levels of the hydrocarbons. AHCs ranged between 7754 and 41,173?ng/g with an average of 25,256?ng/g, while total PAHs varied from 5046 to 33,087?ng/g. n-Alkane indices and PAH diagnostic ratios point to petroleum contamination in the sediments. The significance of PAHs in the sediments was explored using universally accepted interpretation tools. Observed levels of PAHs in sediments of Chitrapuzha are likely to cause adverse effects on biota.     

Pollution characteristics and potential health risk of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in soil/sediment from Baiyin City, North West, China

In order to better understand the environmental behaviors of persistent organic pollutants, the characteristics of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were investigated in twenty-three soil/sediment samples from Baiying City, Northwest China, in 2008. The possible sources and potential health risk of PCDD/Fs were also discussed. The concentrations of PCDD/Fs in nineteen soil samples varied between 20.13 and 496.26 pg/g dry weight (dw.), with an average value of 125.59 pg/g dw. The highest International Toxic Equivalent (I-TEQ) of PCDD/Fs (8.34 pg/g dw.) in soil was found at sample S1 collected from proximity to a copper metallurgy plant. The concentrations of PCDD/Fs in four sediment samples ranged from 37.69 to 491.49 pg/g dw., with an average value of 169.95 pg/g dw. The highest I-TEQ of PCDD/Fs (8.56 pg/g dw.) in sediment was found at sample S12 collected from the East big ditch with waste water discharged into the Yellow River. The results indicated that PCDD/Fs contamination of soil/sediment is originated from three sources: chlorine-containing chemicals, non-ferrous metal industrial PCDD/Fs emission and coal burning. The health risk exposure to PCDD/Fs through soil, dust ingestion and dermal absorption ranged from 0.0006 to 0.0134 pg/kg/day Word Health Organization’s toxic equivalent in 1998 (WHO₁₉₉₈-TEQ) with mean values 0.0032 pg WHO₁₉₉₈-TEQ for adults and varied between 0.0012 and 0.0256 pg/kg/day WHO₁₉₉₈-TEQ with mean values 0.006 pg/kg/day WHO₁₉₉₈-TEQ for children, respectively. These results indicated that health risk of PCDD/Fs for children should be paid more attention.