Risk assessment and remediation suggestion of impacted soil by produced water associated with oil production

Produced water is water trapped in underground formations that is brought to the surface along with oil or gas production. Oilfield impacted soil is the most common environmental problem associated with oil production. The produced water associated with oil-production contaminates the soil and causes the outright death of plants, and the subsequent erosion of topsoil. Also, impacted soil serves to contaminate surface waters and shallow aquifers. This paper is intended to provide an approach for full characterization of contaminated soil by produced water, by means of analysis of both the produced water and the impacted soil using several recommended analytical techniques and then identify and assay the main constituents that cause contamination of the soil. Gialo-59 oilfield (29N, 21E), Libya, has been chosen as the case study of this work. The field has a long history of petroleum production since 1959, where about 300,000 bbl of produced water be discharged into open pit. Test samples of contaminated soil were collected from one of the disposal pits. Samples of produced water were collected from different points throughout the oil production process, and the analyses were carried out at the labs of Libyan Petroleum Institute, Tripoli, Libya. The results are compared with the local environmental limiting constituents in order to prepare for a plan of soil remediation. The results showed that the main constituents (pollutants) that impact the soil are salts and hydrocarbon compounds. Accordingly; an action of soil remediation has been proposed to remove the salts and degradation of hydrocarbons.     

Distribution of heavy metals in agricultural soils near a petrochemical complex in Guangzhou, China

The aim of the study was to investigate influence of an industrialized environment on the accumulation of heavy metals in agricultural soils. Seventy soil samples collected from surface layers (0-20 cm) and horizons of five selected pedons in the vicinity area of petrochemical complex in Guangzhou, China were analyzed for Zn, Cu, Pb, Cd, Hg and As concentrations, the horizontal and vertical variation of these metals were studied and geographic information system (GIS)-based mapping techniques were applied to generate spatial distribution maps. The mean concentrations of these heavy metals in the topsoils did not exceed the maximum allowable concentrations in agricultural soil of China with the exception of Hg. Significant differences between land-use types showed that Cu, Pb, Cd, Hg and As concentrations in topsoils were strongly influenced by agricultural practices and soil management. Within a radius of 1,300 m there were no marked decreasing trends for these element concentrations (except for Zn) with the increase of distance from the complex boundary, which reflected little influence of petroleum air emission on soil heavy metal accumulation. Concentrations of Zn, Cu, Pb, Cd, Hg and As in the five pedons, particularly in cultivated vegetable field and orchard, decreased with soil depth, indicating these elements mainly originated from anthropogenic sources. GIS mapping was a useful tool for evaluating spatial variability of heavy metals in the affected soil. The spatial distribution maps allowed the identification of hot-spot areas with high metal concentration. Effective measures should be taken to avoid or minimize heavy metal further contamination of soils and to remediate the contaminated areas in order to prevent pollutants affecting human health through agricultural products.     

Site environmental assessment to an old paint factory in China

High ethyl-benzene and total petroleum hydrocarbons (TPHs) were found in the soil samples and groundwater samples during a site environmental assessment for an old paint factory in the city Changchun, Jilin province of China. The target old paint plant had been in operation for near 30 years by manufacturing resin and house paint. Driving force for this study was to identify potential environmental contamination existing in this paint factory which is located next to a new resident area under construction. The assessment result would be used as baseline environmental data input for remediation plan when the factory site will be changed into potential resident area in near future. The analytical data from the soil samples from different area of the factory which had high exposure to operation showed that solid waster storage area was contaminated with high heavy metals (Cd, Pb, and Zn) and waster paint storage areas were contaminated with ethyl-benzene, xylene and C9-C30 aromatic hydrocarbon solvent. The analytical data from the groundwater samples from different area of the factory showed that resin plant area and waster paint storage areas were contaminated with high concentration of naphthalene, ethyl-benzene and xylene which exceed the reference standard. Remediation action is recommended.     

Influence of multi-industrial activities on trace metal contamination: an approach towards surface water body in the vicinity of Dhaka Export Processing Zone (DEPZ)

Industrial wastewater discharged into aquatic ecosystems either directly or because of inadequate treatment of process water can increase the concentrations of pollutants such as toxic metals and others, and subsequently deteriorate water quality, environmental ecology and human health in the Dhaka Export Processing Zone (DEPZ), the largest industrial belt of 6-EPZ in Bangladesh. Therefore, in order to monitor the contamination levels, this study collected water samples from composite effluent points inside DEPZ and the surrounding surface water body connected to effluent disposal sites and determined the environmental hazards by chemical analysis and statistical approach. The water samples were analysed by inductively coupled plasma mass spectrometry to determine 12 trace metals such as As, Ag, Cr, Co, Cu, Li, Ni, Pb, Se, Sr, V and Zn in order to assess the influence of multi-industrial activities on metal concentrations. The composite effluents and surface waters from lagoons were characterized by a strong colour and high concentrations of biochemical oxygen demand, chemical oxygen demand, electrical conductivity, pH, total alkalinity, total hardness, total organic carbon, Turb., Cl(-), total suspended solids and total dissolved solids, which were above the limit of Bangladesh industrial effluent standards, but dissolved oxygen concentration was lower than the standard value. The measurement of skewness and kurtosis values showed asymmetric and abnormal distribution of the elements in the respective phases. The mean trend of variation was found in a decreasing order: Zn > Cu > Sr > Pb > Ni > Cr > Li > Co > V > Se > As > Ag in composite industrial effluents and Zn > Cu > Sr > Pb > Ni > Cr > Li > V > As > Ag > Co > Se in surface waters near the DEPZ. The strong correlations between effluent and surface water metal contents indicate that industrial wastewaters discharged from DEPZ have a strong influence on the contamination of the surrounding water bodies by toxic metals. The average contamination factors were reported to be 0.70-96.57 and 2.85-1,462 for industrial effluents and surface waters, respectively. The results reveal that the surface water in the area is highly contaminated with very high concentrations of some heavy/toxic metals like Zn, Pb, Cu, Ni and Cr; their average contamination factors are 1,460, 860, 136, 74.71 and 4.9, respectively. The concentrations of the metals in effluent and surface water were much higher than the permissible limits for drinking water and the world average concentrations in surface water. Therefore, the discharged effluent and surface water may create health hazards especially for people working and living inside and in the surrounding area of DEPZ.     

中国表层水体沉积物中多环芳烃源解析及评价

采用索氏提取气相色谱-质谱法测定中国6个重点水体表层沉积物中16种多环芳烃的含量。各化合物含量范围分别为长江6.20~163 ng/g、淮河7.90~249 ng/g、海河12.1~401 ng/g、松花江5.75~152 ng/g、太湖29.1~2 810 ng/g和滇池19.1~795ng/g;16种多环芳烃的总量分别为：长江1 147 ng/g、淮河1 723 ng/g、海河2 595 ng/g、松花江793 ng/g、太湖12472 ng/g、滇池3 714 ng/g,属中等污染水平。利用特征分子比值法分析结果表明6条水体表层沉积物中PAHs均可能以燃料（包括柴油、汽油、煤、木材）燃烧以及焦化污染为主。淮河和滇池还可能存在轻微石油泄漏污染。利用沉积物质量基准法（SQGs）和沉积物质量标准法分别对6条水体表层沉积物中多环芳烃的风险评估表明严重的多环芳烃生态风险在这些水体表层沉积物中不存在,但长江、淮河、松花江、海河均可能存在一定的潜在风险,负面生物毒性效应会偶尔发生,风险主要来源于荧蒽和菲。太湖和滇池水体中存在的潜在多环芳烃风险种类较多,风险主要来源于菲、荧蒽、芘、苯并（a）蒽、苊和蒽,对水生生物毒性效应较高,有必要进行更深入细致的调查研究高风险区域底栖生物的受损状况、污染来源和途径,以制定合理的污染控制对策。     

In situ laser-induced fluorescence (LIF) analysis of petroleum product-contaminated soil samples

General considerations of the calibrations of in situ measurements are presented and the concept of using an "average oil" with average analysability for calibration purposes is introduced. The in situ analysis of 30 petroleum product-contaminated soil samples with laser-induced fluorescence (LIF) spectroscopy was performed. Compared to an uncontaminated laboratory reference (LR) soil, 23 soil samples exhibited significantly higher LIF signals, so that these soil samples were classified as contaminated. The repeatability and reproducibility of the in situ LIF analysis were investigated. For the calibration of the LIF data, two LR oils (a fuel oil and a crude oil) were employed. The degree of soil contamination with petroleum products ranged from the limit of detection (LOD) for LIF analysis (ca. 100 ppm), or below, to more than 10,000 ppm. The petroleum product concentrations determined with in situ LIF analysis reveal a reasonable correlation with the results of standard IR analysis after extraction of the contaminated soils.     

Evaluation of organic contamination in urban groundwater surrounding a municipal landfill, Zhoukou, China

This paper investigates the organic pollution status of shallow aquifer sediments and groundwater around Zhoukou landfill. Chlorinated aliphatic hydrocarbons, monocylic aromatic hydrocarbons, halogenated aromatic hydrocarbons, organochlorine pesticides and other pesticides, and polycyclic aromatic hydrocarbons (PAHs) have been detected in some water samples. Among the detected eleven PAHs, phenanthrene, fluorine, and fluoranthene are the three dominant in most of the groundwater samples. Analysis of groundwater samples around the landfill revealed concentrations of PAHs ranging from not detected to 2.19 μg/L. The results show that sediments below the waste dump were low in pollution, and the shallow aquifer, at a depth of 18–30 m, was heavily contaminated, particularly during the wet season. An oval-shaped pollution halo has formed, spanning 3 km from west to east and 2 km from south to north, and mainly occurs in groundwater depths of 2–4 m. For PAH source identification, both diagnostic ratios of selected PAHs and principal component analysis were studied, suggesting mixed sources of pyro- and petrogenic derived PAHs in the Zhoukou landfill. Groundwater table fluctuations play an important role in the distribution of organic pollutants within the shallow aquifer. A conceptual model of leachate migration in the Quaternary aquifers surrounding the Zhoukou landfill has been developed to describe the contamination processes based on the major contaminant (PAHs). The groundwater zone contaminated by leachate has been identified surrounding the landfill.     

流域重点工业污染源识别特征成分谱建立技术

研究了基于生产排放全过程、多相、多类污染物并举的污染源识别特征成分谱建立技术。首先建立污染源排放完整图谱,包括原辅料、中间物质、产品、各工艺废水污染物、水处理设施进口和出口污染物等。然后从排放完整图谱中解析出特征污染物。对于废水中的常规污染物和金属污染物,采用与受纳水体浓度相比较的方式得到污染源识别特征污染物,建议将浓度超过受纳水体1倍的污染物定为特征污染物。对于有机污染物,将质量分数之和大于90%的污染物集定为特征有机污染物,并按照有机物类别进行分类。最后开发建立动态的水污染源排放数据库。应用该技术建立了石化行业典型企业的排放特征成分谱,发现这些特征组分具有很好的代表性,为水污染源的识别提供了基础数据。     

Ground water contamination by organochlorine insecticide residues in a rural area in the indo-gangetic plain

Residues of several organochlorine insecticides were monitored in the ground water from a rural area near Farrukhabad in the vicinity of the Ganga River in northern India for one year (1991–1992). Almost all the samples were found to be contaminated with residues of Hexachlorocyclohexane (HCH) and Dichloro-diphenyl-trichloroethane (DDT). Residues of Aldrin, endosulfan and heptachlor were also detected in a large number of samples. The concentrations of aldrin residues greatly exceeded the WHO guideline value for drinking water, concentrations of heptachlor and DDT residues also occasionally exceeded the specified limits. Migration of pollutants through ground water recharge with polluted Ganga River water and monsoon rains carrying undergraded residues downwards from the soil surface are throught to be important sources of insecticide contamination of ground water in the region.     

由石油类应急监测现状探寻水中石油类监测的突破

突发环境事件发生后,对污染物质、污染物浓度、污染范围及其动态变化情况进行监测是环境应急监测的基本工作要求。在不能利用管理手段有效获取污染来源等信息的情况下,开展溯源应急监测成为突发环境事件处理处置的重要需求。然而通过资料调研及应急监测案例分析发现,石油类水体突发环境事件应急监测大多存在采样代表性不够、溯源手段不健全、特征污染物监测不全面,以及现行石油类监测方法不能完整说清污染状况等问题或不足。因此,建议通过优化整合水中石油类指标监测标准,构建与石油类污染特征相适应的技术规范及配套监测分析方法,以达到精准、全面反映石油类水体污染状况的目的。     

Natural attenuation of petroleum hydrocarbons—a study of biodegradation effects in groundwater (Vitanovac,Serbia)

The role of natural attenuation processes in groundwater contamination by petroleum hydrocarbons is of intense scientific and practical interest. This study provides insight into the biodegradation effects in groundwater at a site contaminated by kerosene (jet fuel) in 1993 (Vitanovac, Serbia). Total petroleum hydrocarbons (TPH), hydrochemical indicators (O₂, NO₃^?, Mn, Fe, SO₄^2?, HCO₃^?), δ¹³C of dissolved inorganic carbon (DIC), and other parameters were measured to demonstrate biodegradation effects in groundwater at the contaminated site. Due to different biodegradation mechanisms, the zone of the lowest concentrations of electron acceptors and the zone of the highest concentrations of metabolic products of biodegradation overlap. Based on the analysis of redox-sensitive compounds in groundwater samples, redox processes ranged from strictly anoxic (methanogenesis) to oxic (oxygen reduction) within a short distance. The dependence of groundwater redox conditions on the distance from the source of contamination was observed. δ¹³C values of DIC ranged from ??15.83 to ??2.75‰, and the most positive values correspond to the zone under anaerobic and methanogenic conditions. Overall, results obtained provide clear evidence on the effects of natural attenuation processes—the activity of biodegradation mechanisms in field conditions.     

Partitioning and sources of PAHs in wastewater receiving streams of Tianjin,China

Polycyclic aromatic hydrocarbons (PAHs) partitioning among dissolved phase, suspended particulate matter, pore water, and sediment was studied in one moderately contaminated river (Yongding New River) and two highly contaminated drainage canals (South Drainage Canal and North Drainage Canal) of Tianjin, China. PAHs concentrations in sediment (ranged from 0.2 to 195 μg/g) showed positive relations with both total organic carbon contents (ranged from 0.7% to 31.1%, dw) and black carbon contents (ranged from 0.1% to 2.1%, dw) in the sediments. Moreover, most of the measured organic carbon normalized partition coefficients of PAHs in the three streams were 0.76 to 1.54 log units higher than the predicted values. These indicated that strong and nonlinear sorption of PAHs by carbonaceous geosorbents such as black carbon (BC) existed in the streams, and BC was an important part of the carbonaceous particles controlling the partitioning of PAHs in the sediments of this study. PAH component ratio analyses suggested that PAHs in the three streams, effluent samples from wastewater treatment plants, and soil samples by the riverbank had similar main sources, which is coal/petroleum combustion. We suggested the transportation and transformation of both carbonaceous particles and PAHs during wastewater treatment process, surface runoff, etc, should be studied further in order to make decisions on PAHs controlling measures.     

Water quality associated public health risk in Bo, Sierra Leone

Human health depends on reliable access to safe drinking water, but in many developing countries only a limited number of wells and boreholes are available. Many of these water resources are contaminated with biological or chemical pollutants. The goal of this study was to examine water access and quality in urban Bo, Sierra Leone. A health census and community mapping project in one neighborhood in Bo identified the 36 water sources used by the community. A water sample was taken from each water source and tested for a variety of microbiological and physicochemical substances. Only 38.9% of the water sources met World Health Organization (WHO) microbial safety requirements based on fecal coliform levels. Physiochemical analysis indicated that the majority (91.7%) of the water sources met the requirements set by the WHO. In combination, 25% of these water resources met safe drinking water criteria. No variables associated with wells were statistically significant predictors of contamination. This study indicated that fecal contamination is the greatest health risk associated with drinking water. There is a need to raise hygiene awareness and implement inexpensive methods to reduce fecal contamination and improve drinking water safety in Bo, Sierra Leone.     

石化污水处理场排放废气中有机污染的分析与评价

采用预浓缩、气相色谱-质谱联用及脉冲火焰光度检测的方法对石化污水处理场排放的废气污染物进行了定性与定量分析,并采用相应的污染物排放标准及其人体感知嗅阈值进行了污染程度评价.结果表明,污水处理场在各个采样点位均有挥发性有机污染物和恶臭污染物检出,其中以污水进口最为严重.从检出物的浓度水平而言,苯系物和恶臭污染物均存在超标现象,而且检出的恶臭污染物浓度水平远高于人体感知嗅阈值.     

Polycyclic aromatic hydrocarbons in surface water and bed sediments of the Hungarian upper section of the Danube River

This study was performed to elucidate the distribution, concentration trend and possible source of polycyclic aromatic hydrocarbons (PAHs) in surface water and bed sediments of the Hungarian upper section of the Danube River and the Moson Danube branch. A total of 217 samples (water and sediments) were collected from four different sampling sites in the period of 2001–2010 and analysed for the 16 priority US Environmental Protection Agency PAHs. Concentrations of total 16 PAHs (∑PAHs) in water samples ranged from 25 to 1,208 ng/L, which were predominated by two- and three-ring PAHs. The ∑PAH concentrations in sediments ranged from 8.3 to 1,202.5 ng/g dry weight. Four-ring PAHs including fluoranthene and pyrene were the dominant species in sediment samples. A selected number of concentration ratios of specific PAH compounds were calculated to evaluate the possible sources of PAH contamination. The ratios reflected a pattern of pyrogenic input as a major source of PAHs. The levels of PAHs determined were compared with other sections of the Danube and other regions of the world.     

Identification of sources of elevated concentrations of polycyclic aromatic hydrocarbons in an industrial area in Tianjin, China

The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) were determined by gas chromatography equipped with a mass spectrometry detector in 105 topsoil samples from an industrial area around Bohai Bay, Tianjin in the North of China. Results demonstrated that concentrations of PAHs in 104 soil samples from this area ranged from 68.7 to 5,590 ng g^???1 dry weight with a mean of ∑16PAHs 814 ± 813 ng g^???1, which suggests that there exists mid to high levels of PAH contamination. The concentration of ∑16PAHs in one soil sample from Tianjin Port was exceptionally high (48,700 ng g^???1). Ninety-three of the 105 soil samples were considered to be contaminated with PAHs (>200 ng g^???1), and 25 were heavily polluted (>1,000 ng g^???1). The sites with high PAHs concentration are mainly distributed around chemical industry parks and near highways. Two low molecular weight PAHs, naphthalene and phenanthrene, were the dominant components in the soil samples, which accounted for 22.1% and 10.7% of the ∑16PAHs concentration, respectively. According to the observed molecular indices, house heating in winter, straw stalk combustion in open areas after harvest, and petroleum input were common sources of PAHs in this area, while factory discharge and vehicle exhaust were the major sources around chemical industrial parks and near highways. Biological processes were probably another main source of low molecular weight PAHs.     

Persistent organochlorine pesticide residues in animal feed

Animal products like milk and meat are often found to be contaminated with residues of persistent pesticides and other toxic substances. The major source of entry of these compounds to animal body is the contaminated feed and fodder. So, unless the residues are managed at this stage, it is very difficult to prevent contamination in milk and meat. Therefore, the status of residue level of most persistent organochlorinated pesticides (OCP) in feed and fodder should be monitored regularly. The frequency of occurrence and contamination levels of OCP residues in different kinds of animal concentrate feed and straw samples collected from Bundelkhand region of India were determined. Out of 533 total samples, 301 i.e. 56.47% samples were positive containing residues of different OCPs like hexachlorocyclohexane (HCH) isomers, dichlorodiphenyltrichloroethane (DDT) complex, endosulfan and dicofol. Among different HCH isomers, the mean concentration of ??-HCH was highest, and total HCH varied from 0.01 to 0.306 mg kg^???1. In case of DDT complex, i.e. DDD, DDE and DDT, the concentration ranged between 0.016 and 0.118 mg kg^???1 and the pp^| isomers were more frequently encountered than their op^| counterparts. Endosulfan was also found in some samples in concentration ranging from 0.009 to 0.237 mg/kg, but dicofol could be recorded in very few samples. Although feed samples were found to contain OC residues, after comparing their levels in positive samples with the limiting values of respective pesticides, only very few were found to exceed the threshold level. Otherwise, they were mostly within safe limits.     

Monitoring of pharmaceutically active compounds on the Guadalquivir River basin (Spain): occurrence and risk assessment

Guadalquivir River (South of Spain) is among the major freshwater sources of the European Atlantic basin. Until now scientific efforts have been focused on contamination by heavy metals and some priority pollutants in Guadalquivir River. However, the presence of "emerging contaminants", such as pharmaceutically active compounds, has not yet been studied. In this work the occurrence and risk assessment of sixteen pharmaceutically active compounds, belonging to different therapeutic groups, in Guadalquivir River during its course through Seville city are reported. Wastewater effluents from four wastewater treatment plants discharging into Guadalquivir River and river water samples were analyzed. All studied pharmaceutically active compounds, except sulfamethoxazole, trimethoprim, estrone and clofibric acid, were detected in effluent wastewaters at concentration levels up to 28.9 μg L(-1). Among the pharmaceutically active compounds found in effluent wastewater, seven were present in Guadalquivir River samples at concentration levels up to 0.75 μg L(-1), which indicated an important dilution from effluent discharge. Environmental risk assessment reveals that potential ecotoxicological risk cannot be expected on Guadalquivir River at measured concentration levels. Only, the lipid regulator gemfibrozil showed a medium risk for the environment. The risk for acute toxic effects in the environment with the current use of active pharmaceutical ingredients is unlikely. However, the results do not rule out the potential for chronic environmental effects.     

Polycyclic aromatic hydrocarbon contamination in stormwater detention pond sediments in coastal South Carolina

The purpose of this study was to characterize the polycyclic aromatic hydrocarbon (PAH) contamination in the sediments of stormwater detention ponds in coastal South Carolina. Levels of the sum of PAH analytes were significantly higher in the sediments of commercial ponds compared to that of reference, golf course, low-density residential, and high-density residential ponds. Isomer ratio analysis suggested that the predominant source of PAHs were pyrogenic; however, many ponds had a PAH signature consistent with mixed uncombusted and combusted PAH sources. PAH levels in these sediments could be modeled using both pond drainage area and pond surface area. These results demonstrate that the sediment from most commercial ponds, and a few residential and golf course ponds, were moderately contaminated with PAHs. PAH levels in these contaminated ponds exceeded between 42% and 75% of the ecological screening values for individual PAH analytes established by US EPA Region IV, suggesting that they may pose a toxicological risk to wildlife.     

Evaluation of poly-aromatic hydrocarbons (PAHs) in the aquatic species of Suez Gulf water along El-Sokhna area to the Suez refineries

The Egyptian Red Sea environment especially along El-Sokhna area to the Suez refineries (Suez) is severely contaminated with organic compounds, as well as overfishing. This may be well contributory to recent serious declines in fish stocks. Fish embryos are also particularly vulnerable to oil exposure, even at extremely low concentrations of less than one part per billion. Consequently, even traces of oil pollution at levels often considered safe for wildlife can cause severe damage to fish. Sixteen polycyclic aromatic hydrocarbons (PAHs) were investigated in ten fish species of aquatic species by high performance liquid chromatography (HPLC). The compositions of PAHs determined in all samples were measured in order to use them as chemical markers for identifying different sources of PAH pollutants in the studied region. The total content of these16 PAHs ranged from 399.616 up to 67,631.779 ng/g wet weight. The data show that these values are considered to be alarmingly high enough to cause lethal toxicity effect by accumulation. All studied aquatic species samples are characterized by relatively high concentrations of the six-membered ring PAHs. The origin of PAHs in the collected samples is either petrogenic, biogenic, or mixed petrogenic and biogenic.