Sub-soil contamination due to oil spills in zones surrounding oil pipeline-pump stations and oil pipeline right-of-ways in Southwest-Mexico

Oil spills due to oil pipelines is a very frequent problem in Mexico. Petroleos Mexicanos (PEMEX), very concerned with the environmental agenda, has been developing inspection and correction plans for zones around oil pipelines pumping stations and pipeline right-of-way. These stations are located at regular intervals of kilometres along the pipelines. In this study, two sections of an oil pipeline and two pipeline pumping stations zones are characterized in terms of the presence of Total Petroleum Hydrocarbons (TPHs) and Polycyclic Aromatic Hydrocarbons (PAHs). The study comprehends sampling of the areas, delimitation of contamination in the vertical and horizontal extension, analysis of the sampled soils regarding TPHs content and, in some cases, the 16 PAHs considered as priority by USEPA, calculation of areas and volumes contaminated (according to Mexican legislation, specifically NOM-EM-138-ECOL-2002) and, finally, a proposal for the best remediation techniques suitable for the contamination levels and the localization of contaminants.     

Seasonal and spatial occurrence and distribution of atmospheric polycyclic aromatic hydrocarbons (PAHs) in rural and urban areas of the North Chinese Plain

Passive air sampling (PAS) was employed to study the occurrence of gaseous and particle-bound PAHs in the North Chinese Plain. The averaged concentrations of gaseous and particle-bound PAHs were 485 ± 209 ng/m³ and 267 ± 161 ng/m³, respectively. The PAHs concentrations at urban sites were generally higher than those at rural ones with ratios <1.5 in spring, summer and fall, but differences between them were not significant for the wintertime and annually averaged concentrations. This urban-rural distribution pattern was related to the PAHs emission sources. PAHs spatial variation can be partially (49%) explained by emission with a simple linear regression method. Both the gaseous and particle-bound PAHs were highest in winter and lowest in summer, with winter/summer ratios of 1.8 and 8, respectively. Emission strength was the most important factor for the seasonality.     

Seasonal concentrations and partitioning of PAHs in a suburban site of Bursa, Turkey

Effects of space heating on atmospheric concentrations and gas-particle partitioning of PAHs were investigated in a suburban site of Bursa, Turkey. The average concentrations of ∑₁₅-PAHs in heating season samples were approximately 10 times higher than those of non-heating season samples. The plot of log K_p versus log P_L⁰ for all the data set gave significantly different slopes. The slope for the heating season (−0.75) samples was steeper than the one for the non-heating season (−0.64) samples. It was also observed that partitioning of PAHs for the non-heating season samples showed different characteristics depending on air parcel trajectories. Generally steeper slopes were obtained for the air parcels traveled across the Black sea and arrived to the sampling site from northern sector. On the other hand, the variations in slopes according to air mass origin were insignificant for the heating season samples. Local contributions from space heating are the reason for this observation.     

Accumulation and phytoavailability of benzo[a]pyrene in an acid sandy soil

Effects of benzo[a]pyrene (B[a]P) on ryegrass (Lolium perenne L.) growth, plant accumulation and dissipiation of B[a]P in a red sandy soil (Hapli-Udic Argosol) were studied in a pot experiment. The plants were grown for 61 days in soil spiked with B[a]P at 0, 12.5, 25 and 50 mg kg⁻¹. Control pots without plants were also set up. Soil extractable B[a]P, plant shoot and root biomass, and concentrations of B[a]P in plant shoots and roots were determined. Ryegrass biomass was increased by addition of B[a]P and root B[a]P concentrations were significantly correlated with B[a]P application rate, but no such correlation was found for shoot B[a]P concentrations. This indicates that B[a]P enhanced the growth of the ryegrass. The extractable B[a]P concentration in the planted soil was significantly lower than that in the unplanted control soil at the rate of 50 mg B[a]P kg⁻¹. This indicates that ryegrass may help to dissipate B[a]P in soil at concentrations over 50 mg kg⁻¹ soil although the mechanism for this is not understood.     

4种多环芳烃对仿刺参(Apostichopus japonicus)原肠胚发育的急性毒性研究

海洋中的多环芳烃(PAHs)具有较强的生物毒性,且海洋动物早期发育阶段是对环境因素变化响应的最敏感阶段。为探究海洋多环芳烃类有机污染物对仿刺参(Apostichopus japonicus)早期发育阶段原肠胚的毒性影响,采用半静态毒性实验方法,分别考察了4种多环芳烃苯并[a]芘、3-甲基菲、惹烯及2-甲基蒽对仿刺参原肠胚的24、48、72、96 h急性毒性效应。结果表明,在10、50、100、200μg·L~(-1)暴露浓度下,随着暴露时间的延长和暴露浓度的升高,4种多环芳烃对仿刺参原肠胚产生不同程度的急性毒性效应,仿刺参原肠胚存活率与4种多环芳烃浓度之间分别存在显著的剂量-效应关系(P0.05)。苯并[a]芘对仿刺参原肠胚在24、48 h的半致死浓度(LC_(50))分别为294.4、225.64 mg·L~(-1),3-甲基菲在24、48、72、96 h的LC_(50)分别为404.5、300.7、81.4、17.6mg·L~(-1),惹烯在24、48、72 h的LC_(50)分别为243.1、230、186 mg·L~(-1),2-甲基蒽在24、48、72、96 h的LC_(50)分别244、231.6、152.6、142.9 mg·L~(-1)。4种多环芳烃的安全浓度(SC)分别为39.76、49.8、61.8、62.6μg·L~(-1),其毒性大小顺序为苯并[a]芘3-甲基菲惹烯2-甲基蒽。基于定量构效关系(QSAR)的研究结果可知多环芳烃化合物的毒性差异可能与分子结构等性质有关。该实验为深入研究多环芳烃对海洋环境的毒性效应提供了理论依据。     

某电子垃圾拆解园周边农田土壤中多环芳烃的污染特征及风险评估

研究了某电子垃圾拆解园周边151个农田土壤样品中16种多环芳烃(PAHs)的污染特征和环境风险。结果表明,125个表层土壤样品中PAHs总质量浓度在149.0~2.0×104μg/kg,均值为1 805.5μg/kg,随着剖面土壤深度增加,PAHs含量总体呈递减趋势。通过来源解析,电子拆解园周围土壤中PAHs污染主要由废弃的电子电器元件的粗放燃烧和汽车尾气排放共同引起。土壤风险评估表明,7种类二噁英毒性PAHs的毒性当量(TEQPAH)在6.000×10-5~0.689pg TEQ/g,平均值为0.015pg TEQ/g;苯并(a)芘、二苯并(a,h)蒽、苯并(a)蒽、苯并(b)荧蒽、茚并(1,2,3-cd)芘致癌风险率超出百万分之一的样本比例分别为20.53%、6.62%、1.99%、2.65%、2.65%,其中采样点1、68两个点位表层土壤的苯并(b)荧蒽致癌风险率超过了万分之一。     

Risk Assessment of 26 Polycyclic Aromatic Hydrocarbon (PAH) Compounds in Parkıng Garages

The aim of this study was to determine the level of 26 polycyclic aromatic hydrocarbons (PAHs) at parking garages and to provide the necessary annual information based on occupational inhalation exposure and non-occupational inhalation exposure, which carry risks for the environment. For this purpose, 22 samples were collected continuously from both gas and particulates phase PAHs from two parking garages at Konya City Center, Turkey. The exposure-based risk of these samples was evaluated using concentrations of the carcinogenic PAH compounds. None of the 26 PAHs measured had values exceeding the recommended exposure limits (RELs) standard values for inhalation rate recommended by the World Health Organization (WHO). Exposure levels of gas and particulate PAHs for the occupational group and the public (children and adults who spend time in shopping centers) were found to be 0.07–28.24 μgm^?3 and 0.05–5.753 μgm^?3, respectively, representing levels two to four times higher than those at the control site. Maximum daily inhalation of B[a]Py was estimated at 1.33 ngd^?1 for exposure of the public and as 274 ngd^?1 for the occupational group. It is believed that traffic makes a substantial contribution to the PAH profile, which had relatively high concentrations of naphthalene (Napth) and coronene (Coro). Highly carcinogenic dibenzo(a,l)pyrene (B[al]Pyre) was found in the ambient air at two parking garages. Napth and phenanthrene (Phen) were the main compounds found in nearly all the tested samples. In this study, benzo[e]pyrene (B[e]Py) was used as a reference for PAHs because its concentration is stable and does not change seasonally. Considering the importance of these compounds in relation to human health, the aim of this work was to characterize and quantify the more toxic PAHs in parking garages. Conducting PAH sampling and their chemical analysis is very costly and labor intensive. This study produced data that can be a powerful tool for environmental forensics.     

Polycyclic Aromatic Hydrocarbon (PAH) Contamination of Surface Sediments from Port Dickson,Malaysia: Distribution,Sources and Ecological Risk Assessment

Distribution and sources of 16 parent polycyclic aromatic hydrocarbons (PAHs) were investigated in surface sediments from Port Dickson, Malaysia. Total PAHs varied from 481.3 to 976.6 with a mean value of 679.3 ng g^?1 dry weight, which can be classified as moderate level of pollution. The toxic assessment suggested that the PAHs in sediments will not cause immediately adverse biological effects. Both petrogenic and pyrogenic PAHs were recorded in the study area with dominance of pyrogenic. The authors believe that effective monitoring and implementation of environmental regulations have resulted in a tremendous improvement of sediment quality in the Malaysian aquatic ecosystem.     

生物活性炭法深度处理印染废水及其生物毒性的表征

采用负载经驯化后微生物的活性炭深度处理实际印染废水,研究生物活性炭系统中存在的生物相及其降解有机污染物的作用,并表征了处理后印染废水的生物毒性.结果表明,生物相中含有草履虫、轮虫及钟虫等原生动物.随着运行次数的增加,活性炭反应器在运行5次后出水的COD、NH3-N及色度去除率骤降,但是生物活性炭处理后出水的COD、NH3-N及色度去除率缓慢下降.生物活性炭能很好地降解印染废水中的苯酚类和稠环芳烃污染物.本研究中生物活性炭反应器对氨氮和COD的去除符合一级动力学方程,去除动力学常数分别为1.02和0.96.经过生物活性炭的处理可以将印染废水的生物毒性降到适于小球藻生长的水平.     

珠江三角洲淡水养殖沉积物及鱼体中DDTs和PAHs的残留与风险分析

采用GC-ECD和GC-MS分析了珠江三角洲淡水养殖鱼塘沉积物及鱼体中DDTs、PAHs的质量分数。结果表明,珠江三角洲地区鱼塘积物中DDTs质量分数范围为2.87～8.25ng·g-1,PAHs质量分数分布在61.76～196.05ng·g-1(干物质量)之间;鳙鱼、草鱼等5种鱼肌肉样品中DDTs质量分数为5.47～125.27ng·g-(1湿质量),PAHs质量分数为30.94～410.06ng·g-1(湿质量),5个品种鱼体内DDTs质量分数均未超过国家食用卫生标准。部分鱼塘中含有o,p’-DDT和p,p'-DDT,表明近期曾受到DDT污染。生态风险分析表明,珠江三角洲部分地区DDTs污染生态风险较高。