沙颍河流域某段污染现况及生态风险评价

[目的]选择沙颍河某段为研究对象,评价2011年该河流域某段的整体污染状况,为健康评价提供参考。[方法]分别在丰水期、枯水期采集沙颍河流域内某段河水和底泥及该河段流域内BG村与HS村农田土壤样本进行检测。采用水质综合评价污染指数法对流域内河流水质进行评价;对河流底泥、流域内农田土壤进行潜在生态风险评价。[结果]污染指数水质综合评价法结果显示沙颍河某段丰水期、枯水期3断面均为6级污染等级（WQI为10．0-100．0）;对沙颍河某段底泥进行潜在生态风险评价结果显示,3断面底泥汞的单因子潜在生态风险指数最高（145．520,154．267,135．573）,属于强生态风险（80～160）;BG村、HS村农田土壤中汞的单因子潜在生态风险指数分别为182．253、138．463,分别属于很强生态风险（160—320）和强生态风险（80～160）。[结论]沙颍河丰水期、枯水期河水水质均为严重污染;底泥、土壤中汞污染超标严重,对人群具有强生态风险。     

Seasonal variation and health risk assessment of atmospheric PM<Subscript>2.5</Subscript>-bound polycyclic aromatic hydrocarbons in a classic agglomeration industrial city,central China

Sixty atmospheric sample concentrations of PM_2.5 and polycyclic aromatic hydrocarbons (PAHs) in PM_2.5 were analyzed in distinct seasonal variations from a classic agglomeration industrial city. The concentrations of PM_2.5 ranged from 6.96 to 260.06 μg/m³ with an average of 177.05 μg/m³. Only 38% of the sampling days were superior to the 24-h limit value (75 μg/m³) of ambient air quality standards (AAQs), and the samples from autumn and winter exceeded the limit value. The total PAHs ranged from 1.51 to 44.51 ng/m³ with an average of 10.65 ng/m³. The highest and lowest concentrations of total PAHs appeared in winter and summer with averages of 22.56 and 4.03 ng/m³, respectively. Correlation analysis revealed that high-molecular-weight PAHs (HMW-PAHs) (4-, 5-, 6-ring PAHs) were significantly and negatively correlated with temperature and water-soluble total organic carbon (WTOC), and significantly correlated with water-soluble total nitrogen (WTN). The 4-, 5- and 6-ring PAHs were dominant, especially those of 4-ring PAHs, which were above 30% of the total PAHs in each season. Source apportionment indicated that PM_2.5-bound PAHs in Huangshi were mainly derived from pyrogenic source, vehicle exhaust, coal combustion, and biomass burning. Incremental lifetime cancer risks (ILCRs) showed no potential carcinogenic risk from the PM_2.5-bound BaP-eq. ILCRs in winter were the highest, and the risks for adults were approximately an order of magnitude higher than those for children.     

基于GIS的全国高水碘分布特征及与水系的关系研究

目的掌握全国高水碘地区分布现状和特征,利用地理信息系统(GIS)技术探索高水碘与黄河的关系,为进一步探讨黄泛平原高水碘的形成原因提供依据。方法以2004～2005年全国调查中9省市(安徽、北京、河北、河南、江苏、内蒙古、山东、山西和天津)各乡镇的水碘中位数为依据,采用地理信息系统(GIS)插值生成高水碘分布图,并计算高水碘乡镇到古黄河河道的距离;利用Spearman方法分析距离与水碘的关系。结果 9省市共有735个高水碘乡镇,除山西和内蒙古的高水碘地区独立存在外,其他7省市的高水碘地区主要分布在黄泛平原,沿着黄河及古黄河分布;高水碘乡镇水碘中位数与到古黄河河道的距离成负相关(r_s=-0.125,P0.05),按距离的四分位数将高碘乡镇进行分组,距离最近的乡镇组水碘中位数最高,为276.90μg/L,不同距离组的水碘值差异有统计学意义(χ~2=9.507,P0.05)。结论全国高水碘地区主要集中于黄泛平原,且沿着黄河及古黄河分布,高水碘的形成与黄河有一定的关系。     

GC-MS法分析黄河郑州段水中多氯联苯浓度变化规律

目的 利用气相色谱-质谱联用技术（GC - MS）测定黄河郑州段水中多氯联苯（PCBs）的含量,以探讨PCBs含量随季节、水层和断面的变化规律。方法 水样经C18固相萃取膜富集,以乙酸乙酯 - 正己烷洗脱,GC - MS法测定,利用保留时间定性,内标法定量。结果 18种PCBs的检出限在0.12～0.42 ng/L之间,定量限在0.36～1.26 ng/L之间。加标回收率在90%～118%之间,精密度RSD＜7%(n = 7)。黄河水中18种PCBs在枯水期（三月）为0.00～5.2 ng/L,丰水期（十月）的含量为3.50～24.75 ng/L。结论 黄河郑州段水中的PCBs含量随季节和水层以及不同分段有较大差别,丰水期PCBs的含量要比枯水期的PCBs含量高,底层水中的PCBs含量要高于同点位表层水中PCBs的含量,黄河流经郑州时由于河床变宽,水流变缓PCBs的自然沉降使得下游的大部分PCBs含量低于上游PCBs含量。另外在丰水期只有个别PCBs的含量超出国家限定,其他的值均低于国家规定的20 ng/L标准限值。     

第二松花江吉林市段多环芳烃类有机污染物人体健康风险评价

目的：为研究第二松花江吉林市段多环芳烃类有机污染物对人体健康产生的潜在风险。方法：以第二松花江吉林市段的10座桥和2个渡口为采样点,在枯水期（2月）、平水期（5月）和丰水期（8月）分别采集江水,用气相色谱-质谱联用仪（GC-MS）测定其中15种多环芳烃（PAHs）的含量,以12个采样点江水中15种PAHs的检测质量浓度为基础数据,采用健康评价四步法对PAHs进行人体健康风险评价。结果：第二松花江吉林市段枯水期、平水期和丰水期江水中PAHs的质量浓度范围分别为0.983~4.569μg/L、1.042~5.542μg/L和1.194~4.983μg/L,不同江段和不同水期江水中的PAHs总质量浓度变化较大,江水中PAHs的检出种类和检出总质量浓度基本规律为平水期〉丰水期〉枯水期,城市下游江段〉城市上游江段;人体健康风险值为10-6~10-7。结论：第二松花江吉林市段水体PAHs对人体健康存在风险,但属于可接受范围,水体对于PAHs污染物具有一定承载能力。     

北京市昌平区大气颗粒物中多环芳烃暴露及人群健康风险评价

目的了解北京市昌平区大气颗粒物PM_(10)、PM_(2.5)及多环芳烃(PAHs)的污染水平,分析PAHs的污染来源,并进行人群健康风险评估。方法于2015年1—12月用大气采样器采集北京市昌平区大气样品,分别用称重法和高效液相色谱法检测大气PM_(10)、PM_(2.5)质量浓度和16种PAHs浓度;利用比值法分析PAHs的污染来源,并对其人群健康风险进行评估。结果 2015年北京市昌平区大气PM_(10)和PM_(2.5)的质量浓度范围分别为7.8~343.0μg/m~3和6.3~344.3μg/m~3,年均浓度分别为97.0、78.6μg/m~3;PAHs浓度范围为2.4~383.0 ng/m~3,年均浓度为87.8 ng/m~3。4环PAHs浓度与5、6环PAHs浓度比值范围为0.15~1.38。PAHs的等效毒性浓度以夏季最低(0.354 ng/m~3),冬季最高(29.816 ng/m3)。PAHs对成人及儿童的终身致癌超额风险分别为9.68×10~(-6)和6.14×10~(-6)。结论北京市昌平区大气颗粒物浓度高于GB 3095—2012《环境空气质量标准》二级标准,PAHs污染主要来自本地污染;PAHs对成人的终身致癌风险高于儿童,但两者均处于可接受水平。     

我国水体中苯并(a)芘污染的生态风险评价

目的 对我国部分水体苯并(a)芘[B(a)P]的污染进行生态风险性评价。方法 采用美国佛罗里达洲的海洋和河口沉积物化学品风险评价标准和加拿大淡水水生生物保护临时沉积物质量标准及可能有害生物效应标准两种生态风险评价的标准，对我国主要江河海港水体沉积物中B(a)P的污染水平进行了初步的风险评价。结果 河流、湖泊沉积物中B(a)P的含量为0．06～707．12ng／g，港湾、海域、潮滩表层沉积物中B(a)P的含量为7．1-1492．12ng／g。结论 我国水体普遍受到B(a)P的污染，但基本都还未达到不利生物危害的水平。     

Concentrations, sources and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in soils of Liaohe estuarine wetland

Concentration, source, and risk of PAHs were investigated in 31 sites from surface soils of Liaohe estuarine wetland. Total PAHs concentrations ranged from 293.4 to 1735.9 ng/g with a mean of 675.4 ng/g. The 3- and 4-ring PAHs were the dominant species. The ratios of high-molecular weight PAHs to low-molecular weight PAHs and anthracene/(anthracene+phenanthrene) were calculated to apportion sources of PAHs. It was found that both pyrogenic and petrogenic PAHs sources were important. Effect range low and effect range median showed that the PAHs would occasionally cause adverse effects. The nemerow composite index revealed that about 41.9% soil sampling sites were safety; about 58.1% sites had different grades of PAHs pollution.     

Ecological risk assessment of parent and halogenated polycyclic aromatic hydrocarbons in surface sediments from an urban river in south China

In the present study, 16 priority polycyclic aromatic hydrocarbons (Σ(16) PAHs), including seven carcinogenic PAHs (Σ(7) PAHs) designated by the U.S. Environmental Protection Agency, in surface sediment from an urban river (Shenzhen, south China) were measured. The concentrations of Σ(16) PAHs and Σ(7) PAHs ranged from 27.92 to 7409 ng/g and 0.53 to 2326 ng/g, respectively. Source appointments indicated that the PAHs in surface sediments were mainly derived from coal combustion (36.6%), oil spills (22.2%), vehicle emission (19.5%), and waste incineration (12.1%). The ecological risks posed by PAHs and several halogenated PAHs in these sediment samples were assessed using two redefined guidelines incorporating the toxic equivalency quotients (TEQs) of individual PAH congeners: (1) TEQs effect range-low, and (2) TEQs effect range-median. The authors' results suggested that the PAHs they measured in most of the sediments in this urban river would not cause acute biological effects. On the contrary, the ecological risk posed by some halogenated PAHs was much higher than that of their corresponding parent PAHs. Finally, the relationships between PAH levels and catchment urbanization processes were examined. The results indicated that rapid urbanization has led to an obvious increase in PAH contamination in surface sediments.     

Distribution and Risk Assessment of Antibiotics in a Typical River in North China Plain

We evaluated the occurrence and distribution of 12 antibiotics from the sulfonamide (SAs), fluoroquinolone (FQs) and tetracycline (TCs) groups in the Weihe River, North China. The total antibiotic concentrations in surface water, pore water, and sediment samples ranged from 11.1 to 173.1 ng/L, 5.8 to 103.9 ng/L, and 9.5 to 153.4 μg/kg, respectively. The values of the sediment-water partitioning coefficient in the Weihe River varied widely, from not detected to 943, 2213, and 2405 L/kg for SAs, FQs, and TCs, respectively. The values of the partitioning coefficients between sediment and surface water were generally lower than those between sediment and pore water, which indicated ongoing inputs to the water. The risk assessment showed that there were relatively high ecological risks to aquatic algae in this area from sulfamethoxazole, norfloxacin, tetracycline, ofloxacin, and ciprofloxacin.     

Chlorinated Polycyclic Aromatic Hydrocarbons in Sediments from Industrial Areas in Japan and the United States

Chlorinated polycyclic aromatic hydrocarbons (ClPAHs) are widespread environmental pollutants in the urban environment. Nevertheless, there is little information available regarding the occurrence and profiles of ClPAHs in environmental matrices. In this study, residual concentrations and profiles of 20 individual ClPAHs and 16 US EPA-priority PAHs were determined using high- resolution gas chromatography–high-resolution mass spectrometry in sediments from water bodies near industrialized areas: Tokyo Bay, Japan; the Saginaw River watershed, Michigan, USA; a former chlor-alkali plant, Georgia, USA; and the New Bedford Harbor Superfund site, Massachusetts, USA. A sediment core from Tokyo Bay showed temporal patterns in the distribution of ClPAHs from the 1950s through 2004. The fluxes of ClPAHs and 16 priority PAHs in Tokyo Bay sediment core were 0.029–0.57 ng/cm²/year and 85-609 ng/cm²/year, respectively; fluxes were lowest in the 1950s and highest in 1989–1990. In the United States, a high mean concentration of ClPAHs was found in sediment collected near a former chlor-alkali plant [8820 pg/g dry weight (dry wt)], and lower mean concentrations were found for New Bedford Harbor (1880 pg/g dry wt) and the Saginaw River watershed (1140 pg/g dry wt). Among individual ClPAHs, 6-ClBaP and 1-ClPyr were the dominant compounds in sediments; this pattern is similar to the pattern reported in the literature for waste incineration and ambient urban air samples. Significant correlation between ΣClPAH concentrations and Σparent-PAH concentrations in Tokyo Bay sediment implies that the sources and distribution of ClPAHs are directly related to those of parent PAHs. We also analyzed ClPAHs and parent PAHs in blue mussels from New Bedford Harbor. The mean concentration of ClPAHs in mussels from New Bedford Harbor was 21 ng/g lipid weight, a concentration three orders of magnitude lower than the mean concentration of parent PAHs. Low-molecular-weight ClPAHs predominated in mussel tissues. Toxic equivalents (TEQs) of ClPAHs analyzed in sediment ranged between 1.1 fg TEQ/g dry wt (Tokyo Bay) and 2.4 fg TEQ/g dry wt (Saginaw River watershed). The dioxinlike toxicity contributed by ClPAHs in sediment from contaminated areas was five orders of magnitude lower than that previously reported for dioxins.     

淄博市城区大气PM2.5中多环芳烃污染特征及来源分析

目的 了解淄博市城区大气PM2.5中的多环芳烃(PAHs)污染水平及特征,分析PAHs来源。方法 2017年采集淄博市城区大气中PM2.5颗粒物,用HPLC分析PM2.5颗粒样品中16种PAHs的含量水平,分析其变化规律,利用比值特征法解析PAHs来源。结果 除苊烯外,PM2.5中15种PAHs均有检出,全年PM2.5的平均值为0.087 mg/m3,范围为0.011～0.309 mg/m3;PAHs总含量范围为1.11～361 ng/m3,平均为33.7 ng/m3。 PM2.5和ΣPAHs的含量随季节的变化规律一致。全年中4环多环芳烃的含量随月份增加呈现下降的趋势;2～3环多环芳烃的含量相对稳定。5～6环多环芳烃含量先逐渐上升,在8月份达到峰值,8月份以后含量逐渐下降。淄博为石油化工为主的工业城市,大气PM2.5中多环芳烃受石油化工源及煤来源的综合影响。结论 淄博市大气PM2.5中PAHs冬季污染最为严重,对健康有较高的潜在风险。2017年经过秋冬大气污染治理,大气状况有了明显改善。     

Probabilistic Ecological Risk Assessment and Source Apportionment of Polycyclic Aromatic Hydrocarbons in Surface Sediments from Yellow Sea

Based on the concentrations of polycyclic aromatic hydrocarbons (PAHs) in 12 surface sediment samples from Yellow sea, the relative risk of 9 PAHs was investigated using joint risk probability distribution curves and overlapping area, which were generated based on the distributions of exposure and acute toxicity data (LC₅₀), and the sources of PAHs were apportioned using principal component analysis. It was found that joint probability curve and overlapping area indicated the acceptable ecological risk of individual PAHs, only a small fraction of the benthic organisms was affected. Among the nine PAHs studied, the overall risk of pyrene was the highest, with that of naphthalene the lowest. For lower exposure levels at which the percentage of species affected was less than 10%, the risk associated with phenanthrene and fluorene were clearly higher than that of the other seven PAHs. It was indicated that PAHs in surface sediments mainly originated from vehicular emissions, coal combustion sources, coke oven emission and wood combustion, petroleum origin made little influence on sources of PAHs by PCA.     

Studies on bioremediation of polycyclic aromatic hydrocarbon-contaminated sediments: bioavailability,biodegradability, and toxicity issues

The widespread contamination by polycyclic aromatic hydrocarbons (PAHs) has created a need for cost-effective bioremediation processes. This research studied a chronically PAH-contaminated estuarine sediment from the East River (ER; NY, USA) characterized by high concentrations of PAHs (approximately 4-190 ppm), sulfide, and metals and a marine sediment from New York/ New Jersey Harbor (NY/NJH; USA) with only trace quantities of PAHs (0.1-0.6 ppm). The focus was to examine the relationship between bioavailability of PAHs and their biological removal in a slurry system. Freshwater and marine sediment toxicity tests were conducted to measure baseline toxicity of both sediments to amphipods, aquatic worms, fathead and sheepshead minnow larvae, and a vascular plant; to determine the cause of toxicity; and to evaluate the effectiveness of the biotreatment strategies in reducing toxicity. Results showed the ER sediment was acutely toxic to all freshwater and marine organisms tested and that the toxicity was mainly caused by sulfide, PAHs, and metals present in the sediment. In spite of the high toxicity, most of the PAH compounds showed significant degradation in the aerobic sediment/water slurry system if the initial high oxygen demand due to the high sulfide content of the sediment was overcome. The removal of PAHs by biodegradation was closely related to their desorbed amount in 90% isopropanol solution during 24 h of contact, while the desorption of model PAH compounds from freshly spiked NY/NJH sediment did not describe the bioavailability of PAHs in the East River sediment well. The research improves our understanding of bioavailability as a controlling factor in bioremediation of PAHs and the potential of aerobic biodegradation for PAH removal and ecotoxicity reduction.     

Analysis of trace organic contaminants in sediment,pore water,and water samples from Onsan Bay,Korea: instrumental analysis and in vitro gene expression assay

Persistent organic pollutants and alkylphenols (APs) were determined in sediment and water samples from Onsan Bay, Korea, by using instrumental analysis and in vitro gene expression cell bioassay. Polycyclic aromatic hydrocabons (PAHs) were the predominant compounds in sediments with concentrations as great as 573 ng/g dry weight. The PAH concentrations were elevated in sediment from inland rivers that flow through Onsan City (mean: 116 ng/g dry wt) and discharge into Onsan Bay. Concentrations of polychlorinated biphenyls (PCBs) in sediments ranged from <1.00 to 56.2 ng/g dry weight. Among different organochlorine (OC) pesticides analyzed (hexachlorobenzene, hexachlorocyclohexanes, chlordanes, and DDTs), DDT concentrations were the greatest, ranging from <0.01 to 7.58 ng/g dry weight. The spatial gradient of contaminant concentrations suggested that streams and rivers are the major sources of PCBs, PAHs, and APs to the bay. Maximum concentrations of nonylphenol, octylphenol, and bisphenol A in sediments were 860, 11, and 204 ng/g dry weight, respectively. Screening of Onsan Bay sediment samples for dioxinlike activity with the H4IIE-luc in vitro cell bioassay revealed that 17 of 22 samples contained significant dioxinlike activity. Further fractionation of sediment extracts indicated that mid-polar and more polar fractions were responsible for the significant dioxinlike activity. Based on a mass balance analysis, PAHs apparently accounted for only a small portion of dioxinlike responses elicited by sediment extracts. Only one raw extract of sediment elicited a significant estrogenic response by MVLN cells. The combination of instrumental analysis and in vitro bioassay was useful to assess sediment quality and characterize the causative agents or potential toxic compounds present.     

Trace Organic Contaminants in Sediment and Water from Ulsan Bay and Its Vicinity, Korea

Sediment and water samples collected from 32 locations in Ulsan Bay and adjacent inland areas were analyzed for polycyclic aromatic hydrocabons (PAHs), nonylphenol (NP), octylphenol (OP), bisphenol A (BPA), organochlorine (OC) pesticides (HCB, HCHs, CHLs, and DDTs), and polychlorinated biphenyls (PCBs) to characterize their spatial distribution and contamination status. PAHs were detected in nearly all sediment and water extracts from Ulsan Bay and its inland locations. The sedimentary PAH concentrations ranged from 17 to 3,100 ng/g on a dry weight basis (DW), which were predominated by two- and three-ring aromatic hydrocarbons in river and/or stream, and four- to six-ring compounds in Ulsan Bay sediment. Concentrations of PAHs in pore water samples were generally two or three orders magnitude less than those of corresponding sediment samples. Maximum concentrations of NP, OP, and BPA in sediments were 1,040, 120, and 54 ng/g DW, respectively. Concentrations of OP and BPA were, on average, 5- to 13-fold less than those of NP. PCB concentrations in sediment ranged from 1.4 to 77 ng/g DW, which were predominated by lower chlorinated congeners such as di- through pentachlorinated biphenyls. Among different OC pesticides analyzed, concentrations of DDTs were the greatest, ranging from 0.02 to 41.9 ng/g DW. NP concentrations were greater at inner locations proximal to municipal wastewater discharges into rivers and/or streams, whereas the concentrations of PCBs and PAHs were great near the sites of high industrial activities. Sediment-pore water partitioning coefficients correlated with those of reported K _oc or K _ow values for selected PAHs in Ulsan Bay, but these varied by an order of magnitude for stream and/or river sediments. Received: 11 June 2000/Accepted: 28 August 2000     

Cadmium and Lead Levels Along the Estuarine Ecosystem of Tigre River-San Andres Lagoon, Tamaulipas, Mexico

Cadmium and lead levels were evaluated in water and sediment along the estuarine ecosystem of Tigre River-San Andres Lagoon (Gulf of Mexico) during September to December 2009. Significant highest metal concentration in water (0.45?mg?L(-1)?Cd and 3.94?mg?L(-1)?Pb) and sediment (2.83?mg?kg(-1)?Cd and 6.61?mg?kg(-1)?Pb) were found at the mouth of the Tigre River, where the fishing town of El Moron is located. Cadmium levels in sediment were above limits associated with adverse biological effects on aquatic fauna, so negative impacts on natural populations of aquatic organisms would be expected to occur. This in turn could affect the fishery resources inhabiting this ecosystem.     

Runoff of genotoxic compounds in river basin sediment under the influence of contaminated soils

Contaminated sites must be analyzed as a source of hazardous compounds in the ecosystem. Contaminant mobility in the environment may affect sources of surface and groundwater, elevating potential risks. This study looked at the genotoxic potential of samples from a contaminated site on the banks of the Taquari River, RS, Brazil, where potential environmental problems had been identified (pentachlorophenol, creosote and hydrosalt CCA). Samplers were installed at the site to investigate the drainage material (water and particulate soil matter) collected after significant rainfall events. Organic extracts of this drained material, sediment river samples of the Taquari River (interstitial water and sediment organic extracts) were evaluated by the Salmonella/microsome assay to detect mutagenicity and by Allium cepa bioassays (interstitial water and whole sediment samples) to detect chromosomal alterations. Positive mutagenicity results in the Salmonella/microsome assay of the material exported from the area indicate that contaminant mixtures may have drained into the Taquari River. This was confirmed by the similarity of mutagenic responses (frameshift indirect mutagens) of organic extracts from soil and river sediment exported from the main area under the influence of the contaminated site. The Allium cepa test showed significant results of cytotoxicity, mutagenic index and chromosome aberration in the area under the same influence. However, it also showed the same similarity in positive results at an upstream site, which probably meant different contaminants. Chemical compounds such as PAHs, PCF and chromium, copper and arsenic were present in the runoff of pollutants characteristically found in the area. The strategy employed using the Salmonella/microsome assay to evaluate effects of complex contaminant mixtures, together with information about the main groups of compounds present, allowed the detection of pollutant dispersion routes from the contaminated site to the Taquari River sediment.     

Sediment Contamination in Lyons Creek East, a Tributary of the Niagara River: Part I. Assessment of Benthic Macroinvertebrates

Sediments in Lyons Creek East (Welland, Ontario), a tributary of the Niagara River and part of the Niagara River Area of Concern, which exceed screening-level environmental-quality criteria for multiple contaminants, were assessed for biological impacts using information from multiple lines of evidence. An initial chemical survey indicated the primary contaminants of concern to be polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), zinc, and p,p′-DDE due to frequent exceedences of sediment guidelines. A subsequent study focused on the chemical composition of sediment, status of benthic invertebrate communities, contaminant bioaccumulation in resident benthos, and sediment toxicity to laboratory-exposed organisms. Chemical and biological conditions in the creek were compared with those in reference creeks using both multivariate (cluster analysis and ordination) and univariate (regression) techniques. Sediment PCBs (≤19 μg/g), PAHs (≤63 μg/g), and Zn (≤7969 μg/g) were increased above the sediment-quality guidelines along most of the creek; however, the upper 1.5 km portion of the creek was the most highly contaminated and therefore the main focus for biological study. Although severe toxicity was evident at several locations in the upper creek, resident benthic communities were minimally affected by sediment contamination. The cause of toxicity was likely related to a combination of stressors, including PCBs, PAHs, and metals. Due to its biomagnifiable nature, bioaccumulation focused on PCBs; concentrations in resident macroinvertebrates were ≤2 orders of magnitude greater than those found in reference creeks and were above tissue residue guidelines, indicating a potential risk for consumers of benthos. This risk was not limited to the upper 1.5 km where other effects were seen.     

Heavy Metals in the Surface Sediments in Lanzhou Reach of Yellow River,China

The heavy metal pollution and their fractionations in the surface sediments of Yellow River in Lanzhou Reach was monitored for arsenic (As), lead (Pb), Zinc (Zn), chromium (Cr), copper (Cu) and manganese (Mn) with Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). The mean sediment concentrations (in μg/g dry weight) ranged from 13.68–48.11 (As), 26.39–77.66 (Pb), 89.80–201.88 (Zn), 41.49–128.30 (Cr), 29.72–102.22 (Cu), and 773.23–1459.69 (Mn). Spatial distribution showed that each heavy metal concentration remained almost constant in this reach. Correlation coefficients indicated that metals were not strongly associated with sediment sand content or organic carbon content (f_oc). Labile fractions (exchangeable + carbonate + Fe–Mn oxide) had no significant correlations with sand content or f_oc, either. Results from the present study are useful for understanding heavy metal distributions in a torrential river sediment environment.