TPH-contaminated Mexican Refinery Soil: Health Risk Assessment and the First Year of Changes

The soil of a coastal Mexican refinery is quite contaminated, especially by hydrocarbons, with detected concentrations up to 130000 mg kg(-1) as TPHs (total petroleum hydrocarbons). The main sources of contamination are pipelines, valves, and old storage tanks, besides the land disposal of untreated hydrocarbon sediments derived from the cleaning of storage tanks. A health risk assessment (HRA) was carried out in order to measure the risk hazard indexes and clean-up standards for the refinery soil. HRA suggested the following actions to be taken: benzene concentrations must be reduced in eight of the 16 studied refinery zones to 0.0074-0.0078 mg kg(-1). Also, vanadium concentration must be reduced in two zones up to a concentration of 100 mg kg(-1). In only one of all of the studied zones, benzo(a)pyrene concentration must be reduced to 0.1 mg kg(-1). After 1 yr, TPHs showed a diminution of about 52%. Even though TPHs concentrations were variable, during 1999 the average concentrations were as much as 15.5 times the goal concentration. For year 2000, TPHs concentrations were only 7.4-fold the proposed value. For the 1999-2000 period, PAHs (polycyclic aromatic hydrocarbons) concentrations decreased by 82%. Some PAHs with 2, 3, 4, and 5 aromatic rings were removed up to 100% values.     

Distribution of PAHs in Surface Soils from Petroleum Handling Facilities in Calabar

The level of concentrations of polycyclic aromatic hydrocarbons (PAHs) in surface soils from petroleum handling facilities (kerosene tank, generating plant, petrol stations, mechanic workshops, leaking pipeline and air port fuel dump) from Calabar metropolis southeastern Nigeria was determined by gas chromatography/ mass spectrometry. The results show that total polycyclic aromatic hydrocarbons (PAHs) varied from 1.80 to 334.43 mg/kg with a mean of 50.31 mg/kg. The lowest value of 1.80 mg/kg was obtained from petrol station while the highest value of 334.43 mg/kg was obtained from facility characterised by petrol stations and mechanic workshops. The ratio of phenanthrene/anthracene and fluoranthene/pyrene, varied from 0.43 to 27.72 and from 0.14 to 17.76 respectively. These ratios indicate various sources for the PAH. The two to three ring PAHs are the most abundant. Based on the PAH ratios and content alone it is not possible to distinguish between contribution from motor vehicle exhaust, gasoline spillage, used engine oil or petroleum production. However, considering the area of the study, it is very likely that the major source of soil contamination is originating from petroleum product.     

Assessment of hydrocarbons concentration in marine fauna due to Tasman Spirit oil spill along the Clifton beach at Karachi coast

On 27 July 2003, Tasman Spirit spilled 31,000 tonnes of crude oil into the sea at the Karachi coast. This disaster badly affected the marine life (Flora and Fauna.) Present research has been proposed to ascertain the level of Polycyclic Aromatic hydrocarbons (PAHs) contamination in different fisheries including Fishes, Crustaceans; Crabs and Shrimps, Mollusks and Echinoderms along with passing time. Heavier components of crude oil such as Polycyclic Aromatic Hydrocarbons (PAHs) appear to cause most damages as these are relatively unreactive and persist in water. High concentrations of toxic PAHs were observed in all the fisheries and shellfishes caught form oil-impacted area. In this study fishes were found most contaminated than shellfishes i.e. summation operator 16 PAH = 1821.24 microg/g and summation operator 1164.34 microg/g, respectively. Naphthalene was found in the range of 0.042-602.23 microg/g. Acenaphthylene, acenaphthene, fluorene, phenanthrene and anthracene were detected in the range 0.008-80.03 microg/g, fluoranthene, pyrene, benzo(a)anthracene and chrysene 0.0008-221.32 microg/g, benzo(b) fluoranthene, benzo(k)fluoranthene and benzo(a) pyrene 0.0005-7.71 microg/g, benzo(g,h,i)perylene and indeno(1,2,3-c,d)pyrene 0.02-503.7 microg/g. Dibenzo(a,h)anthracenre was not detected in any specie.     

Spatial distribution and concentration assessment of total petroleum hydrocarbons in the intertidal zone surface sediment of Todos os Santos Bay, Brazil

The primary objective of this study was to investigate the concentrations and spatial distribution of the total petroleum hydrocarbons (TPHs) in the intertidal zone surface sediment of Todos os Santos Bay, Brazil, to assess the distribution and degree of contamination by TPHs, measure the level of TPH degradation in the surface sediment, and identify the organic matter sources. The surface sediment used in this study was collected in 50 stations, and TPHs, isoprenoid alkanes (pristane and phytane), and unresolved complex mixture (UCM) were analyzed by gas chromatography with a flame ionization detector. The total concentrations ranged from 0.22 to 40,101 μg g^?1 dry weight and showed a strong correlation with the total organic carbon (TOC) content. The highest TPH concentrations were observed in samples from the mangrove sediments of a river located near a petroleum refinery. Compared with other studies in the world, the TPH concentrations in the intertidal surface sediment of Todos os Santos Bay were below average in certain stations and above average in others. An analysis of the magnitude of UCM (0.11 to 17,323 μg g^?1 dry weight) and the ratios nC17/Pr and nC18/Ph suggest that an advanced state of oil weathering, which indicates previous contamination. The molar C/N ratios varied between 5 and 43, which indicate organic matter with a mixed origin comprising marine and continental contributions.     

Habitat Conditions and Correlations of Sediment Quality Triad Indicators in Delaware Bay

This paper summarizes sampling results from NOAA's National Status and Trends (NS&T) Program for marine environmental quality in Delaware Bay. A stratified-random design was used to determine the spatial extent of sediment contamination and toxicity in Delaware Bay from offshore stations in the coastal zone, the lower estuary, the upper estuary, the fresh/salt mixing zone, and tidal fresh areas. Sediment samples were taken for chemical analyses of major classes of environmental contaminants, a suite of toxicity bioassays, and benthic macrofaunal community assessment to identify patterns of resident species. The tidal-fresh areas and portions of the mixing zone of the study area were heavily contaminated. Contaminant concentrations were frequently above the 90th percentile of EMAP Virginian Province levels. PAHs in the sediment were higher than previously documented, with a major component of PAHs being pyrogenic in origin. Bioassay results were highly variable. Toxicity and contaminant levels were correlated when aggregated into indices, but were only marginally correlated with benthic community impacts. High and low abundance stations were found in all zones. Most of the tidal fresh stations were dominated by pollution tolerant species. Species diversity and abundance were generally lowest in the fresh/salt mixing zone.     

武汉市东西湖农场表层土壤中多环芳烃的含量分布特征

对武汉市东西湖农场土壤中多环芳烃的含量调查表明,除紧靠马路边、居民区的土壤中多环芳烃的浓度高于荷兰制定的土壤修复标准之外,其余地方均在此标准值之内,其中主要是高环多环芳烃含量超标严重。证明了汽车尾气所排放的多环芳烃要高于居民日常生活的排放量。多环芳烃在水平方向上的迁移存在色谱效应。     

Effect of land use activities on PAH contamination in urban soils of Rawalpindi and Islamabad, Pakistan

Urbanization can increase the vulnerability of soils to various types of contamination. Increased contamination of urban soils with polycyclic aromatic hydrocarbon (PAH) could relate to increased number of petrol pump stations and mechanical workshops—a phenomenon that needs to be constantly monitored. This study was undertaken to explore the soil PAH levels in Rawalpindi and Islamabad urban areas in relation to land use activities. Composite soil samples from petrol pump stations and mechanical workshops (n?=?32) areas were evaluated for five PAHs––naphthalene, phenanthrene, pyrene, benzo[a]pyrene, and indeno(1,2,3-cd)pyrene—and compared with control area locations with minimum petroleum-related activity (n?=?16). Surface samples up to 3 cm depth were collected and extraction of analytes was carried out using n-hexane and dichloromethane. Prior to running the samples, standards (100 μg ml^–1) were run on HPLC to optimize signal to noise ratio using acetonitrile as mobile phase at a flow rate of 1.25 ml/min at 40 °C. Significant differences between petrol pump stations and mechanical workshop areas were observed for individual PAH as well as with control area soil samples. Naphthalene was found to be the most abundant PAH in soil, ranging from 2.47 to 24.36 mg kg^–1. Correlation between the benzo[a]pyrene (BaP) level in soil and the total PAH concentration (r?=?0.82, P?<?0.0001) revealed that BaP can be used as a potential marker for PAH pollution. A clear segregation between petrogenic and pyrogenic sources of contamination was observed when low molecular weight PAHs detected in soil was plotted against high molecular weight PAHs. The former source comprised lubricants and used engine oil found at mechanical workshops, whereas the latter could be mostly attributed to vehicular emission at petrol pumps. The results indicate that PAH contamination in urban areas of Rawalpindi and Islamabad has direct relevance with land use for petroleum activity. We conclude that in order to reduce the soil PAH exposure in urban environment, petrol pumps and mechanical workshops must be shifted to less densely populated areas because of their role as important point sources for PAH emission.     

The effects of pipeline construction disturbance on soil properties and restoration cycle

Disturbance to the physical–chemical properties of soil caused by pipeline installation was evaluated using two soil quality indices to identify the scale of disturbance and the restoration cycle. The integrated soil quality index (SQI) was used to evaluate soil property changes in different pipeline zones (0, 10, 20, and 50 m from the pipeline) at sites 1 and 2. The soil restoration index (SRI) was used to estimate soil recovery from three pipelines with different recovery periods (2, 6, and 8 years) at site 3. The results showed that the adverse effects of pipeline construction on soil properties mainly occurred in the right-of-way (ROW) areas and the impaired zones were in the order trench?>?piling and working areas?>?20 and 50 m. The soil restoration cycle may be complete within 6 years of construction. At site 3, the SRI in the ROW area of a pipeline after 6 years of restoration was close to 100 %, showing full soil recovery. However, the SRI in the disturbed areas of a pipeline after 2 years of restoration was much lower than that after 6 years of restoration, indicating that the soil was still recovering from the disturbance. The topography may change the intensity of disturbance in different areas due to the movement patterns of heavy machinery and traffic routes. There were local variations in the SQI within the pipeline zones, with flat areas suffering greater disturbance than hilly areas, indicating that topography should be considered in a pipeline’s environmental impact assessment.     

The distribution and composition of hydrocarbons in sediments from the Fladen Ground, North Sea, an area of oil production

The distribution and composition of hydrocarbons in sediment from the Fladen Ground oilfield in the northern North Sea have been investigated. The total PAH concentrations (2- to 6-ring parent and alkylated PAHs, including the 16 US EPA PAHs) in sediments were relatively low (<100 microg kg(-1) dry weight). The PAH, the Forties crude and diesel oil equivalent concentrations were generally higher in sediment of fine grain size and higher organic carbon concentration. PAH distributions and concentration ratios indicated a predominantly pyrolytic input, being dominated by the heavier, more persistent, 5- and 6-ring compounds, and with a high proportion of parent PAHs. The n-alkane profiles of a number of the sediments contained small, high boiling point, UCMs, indicative of weathered oil arising from a limited petrogenic input. The geochemical biomarker profiles of the sediments that contained UCMs showed a small bisnorhopane peak and a high proportion of norhopane relative to hopane, indicating that there was contamination from both Middle Eastern and North Sea oils. Therefore contamination was not directly as a result of oil exploration activity in the area. The most likely source of petrogenic contamination was from general shipping activity.     

Forensic fingerprinting and source identification of the 2009 Sarnia (Ontario) oil spill

This paper presents a case study in which integrated forensic oil fingerprinting and data interpretation techniques were used to characterize the chemical compositions and determine the source of the 2009 Sarnia (Ontario) oil spill incident. The diagnostic fingerprinting techniques include determination of hydrocarbon groups and semi-quantitative product-type screening via gas chromatography (GC), analysis of oil-characteristic biomarkers and the extended suite of parent and alkylated PAH (polycyclic aromatic hydrocarbon) homologous series via gas chromatography-mass spectrometry (GC-MS), determination and comparison of a variety of diagnostic ratios of "source-specific marker" compounds, and determination of the weathering degree of the spilled oil, and whether the spilled oil hydrocarbons have been mixed with any other "background" chemicals (biogenic and/or pyrogenic hydrocarbons). The detailed chemical fingerprinting data and results reveal the following: (1) all four samples are mixtures of diesel and lubricating oil with varying percentages of diesel to lube oil. Both samples 1460 and 1462 are majority diesel-range oil mixed with a smaller portion of lube oil. Sample 1461 contains slightly less diesel-range oil. Sample 1463 is majority lubricating-range oil. (2) The diesel in the four diesel/lube oil mixture samples was most likely the same diesel and from the same source. (3) The spill sample 1460 and the suspected-source sample 1462 have nearly identical concentrations and distribution patterns of target analytes including TPHs, n-alkane, PAHs and biomarker compounds; and have nearly identical diagnostic ratios of target compounds as well. Furthermore, a perfect "positive match" correlation line (with all normalized ratio data points falling into the straight correlation line) is clearly demonstrated. It is concluded that the spill oil water sample 1460 (#1, from the water around the vessel enclosed by a boom) matches with the suspected source sample 1462 (#3, from the vessel engine room bilge pump). (4) From the n-alkane and PAH analysis, it appears that the oil in the spill sample 1460 is slightly more weathered in comparison with sample 1462. The minor differences in fingerprints of two samples were most likely caused by weathering effects. (5) Sample 1461 (#2, from the vessel engine room bilge) and sample 1463 (#4, from the vessel bilge waste collection tank) demonstrated significantly different fingerprints and diagnostic ratios of target compounds from that of spill sample 1460. This was caused most likely by percentages of diesel to lube oil in these two samples different from that in spill sample 1460.     

Potential effects of large linear pipeline construction on soil and vegetation in ecologically fragile regions

Long-distance pipeline construction results in marked human disturbance of the regional ecosystem and brings into question the safety of pipeline construction with respect to the environment. Thus, the direct environmental impact and proper handling of such large projects have received much attention. The potential environmental effects, however, have not been fully addressed, particularly for large linear pipeline projects, and the threshold of such effects is unclear. In this study, two typical eco-fragile areas in western China, where large linear construction projects have been conducted, were chosen as the case study areas. Soil quality indices (SQI) and vegetation indices (VI), representing the most important potential effects, were used to analyze the scope of the effect of large pipeline construction on the surrounding environment. These two indices in different buffer zones along the pipeline were compared against the background values. The analysis resulted in three main findings. First, pipeline construction continues to influence the nearby eco-environment even after a 4-year recovery period. During this period, the effect on vegetation due to pipeline construction reaches 300 m beyond the working area, and is much larger in distance than the effect on soil, which is mainly confined to within 30 m either side of the pipeline, indicating that vegetation is more sensitive than soil to this type of human disturbance. However, the effect may not reach beyond 500 m from the pipeline. Second, the scope of the effect in terms of distance on vegetation may also be determined by the frequency of disturbance and the intensity of the pipeline construction. The greater the number of pipelines in an area, the higher the construction intensity and the more frequent the disturbance. Frequent disturbance may expand the effect on vegetation on both sides of the pipeline, but not on soil quality. Third, the construction may eliminate the stable, resident plant community. During the recovery period, the plant community in the work area of the pipeline is replaced by some species that are rare or uncommon in the resident plant community because of human disturbance, thereby increasing the plant diversity in the work area. In terms of plant succession, the duration of the recovery period has a direct effect on the composition and structure of the plant community. The findings provide a theoretical basis and scientific foundation for improving the environmental impact assessment (EIA) of oil and gas pipeline construction as it pertains to the desert steppe ecosystem, and provide a reference point for recovery and management of the eco-environment during the pipeline construction period.     

Biomarkers of environmental contaminants in the coastal waters of Estonia (Baltic Sea): effects on eelpouts (Zoarces viviparus)

The eastern Baltic Sea near the Estonian coast is heavily navigated by numerous cargo ships and oil tankers. Hundreds of accidents and oil spills happen yearly in this area. Yet, there is a lack of data concerning the distribution and effects of the environmental contaminants, especially polycyclic aromatic hydrocarbons (PAHs). Different parts of the Baltic Sea have different levels of contamination; therefore a wide range of monitoring stations in coastal areas in the Gulf of Finland and Gulf of Riga were chosen. The aim of the present research was to document the responses of chosen biomarkers of environmental contaminants in different unstudied areas of the Estonian coastal sea. During 2009 and 2010 we measured PAH metabolites, EROD activities, geno- and cytotoxicity, histology, parasites and other biomarkers from the eelpout (Zoarces viviparus), a resident benthic fish species. The results showed that fish from the Gulf of Riga emitted lower levels of fluorescence in fixed wavelength analyses (representing equivalents of PAH metabolites in bile and urine), and consistently, showed less geno- and cytotoxicity and parasite infection, higher liver somatic index (LSI) and a higher condition factor (CF) than fish inhabiting areas close to the Baltic proper and in the Gulf of Finland. The results point to the effect of long-range contaminant transportation, whether atmospheric or hydrodynamic, and also to the intensive shipping activity in international routes. This study fills the gap of knowledge in this area that has persisted until now. Nevertheless, more studies in this area on the different groups of contaminants are necessary, to specify the factors that are responsible for observed biological effects.     

膜、柱串联固相萃取-高效液相色谱法测定水中多环芳烃(PAHs)的研究

建立了用膜-柱串联固相萃取(SPE)技术,甲醇和水作为流动相进行梯度洗脱,紫外和荧光检测器串联的高效液相色谱法(HPLC)分析水中EPA优先监控的16种PAHs的方法.     

Determination of Hydrocarbons in Mussels from the Egyptian Red Sea Coast

Mussels (Brachidontes Sp.) collected in April 2000 from the Red Sea coastal of Egypt in order to determine the contamination by hydrocarbons. The study included 11 sampling stations covering about 450 Km of the Egyptian Red Sea coast for the first time. Total concentrations of 20 aliphatics (average 0.105 ng g(-1) of wet weight) and sixteen polycyclic aromatic hydrocarbons (PAHs) (average 5452 ng g(-1) of wet weight) were generally lower in comparison with those reported for some of the published surveillance and monitoring studies of coastal areas from various regions. These results suggest that the coastal area in the Red Sea of Egypt might be considered as a relatively unpolluted.     

One-year monitoring survey of organic compounds (PAHs, PCBs, TBT), heavy metals and biomarkers in blue mussels from the Arcachon Bay, France

Marine mussels Mytilus sp. were transplanted on a monthly basis in cages over one year to oyster farms and harbours in the Arcachon Bay (France) in order to assess the water quality of the bay. Contaminant levels (organotin compounds, trace metals, PCBs and PAHs) were measured in tissues of transplanted mussels and mussels from a reference station, along with physiological parameters of the mussels (condition indexes, lipid content and dry weight). Four biomarkers (AChE: acetylcholinesterase activity, GST: gluthathione S-transferase activity, CAT: catalase activity and TBARS: thiobarbituric acid-reactive substance content) were also monitored. The remote stations monitored (oyster parks) exhibited no accumulation pattern of pollutants. Their respective concentrations therefore constitute a background level of the contamination in the bay ([TBT]= 30 ng Sn g(-1) dw, [SigmaHAPs]= 100 ng g(-1) dw, [SigmaPCBs]= 35 ng g(-1) dw). The elevated chemical contamination of the largest harbour of the bay, the Arcachon harbour, can be interpreted in terms of persistence of organotin compounds ([SigmaOTs]= 1500-2000 ng Sn g(-1) dw) and PAHs ([SigmaHAPs]= 4500-5000 ng g(-1) dw) in sediments and, to a lesser extent, of direct inputs of copper ([Cu]= 20 microg g(-1) dw in harbours versus 7 in oyster parks) and petrogenic PAHs ([methylphenanthrenes]= 1600 ng g(-1) dw in the dockyard versus 170 at the gas stations), related to the use of copper-based antifouling paints and to dockyard activity, respectively. However, the Arcachon Bay presents a low contamination level by PCBs and metals, including harbour stations. Furthermore, higher levels of other PAHs (particularly alkyl PAHs such as methylphenanthrenes/1600 ng g(-1) dw) not included in the 16 PAHs from the EPA priority list (usually studied in biomonitoring programmes/1500 ng g(-1) dw) in the Arcachon harbour underline the need to integrate these compounds in biomonitoring of highly PAH-polluted areas such as harbours in order to avoid misinterpretation of the biological responses observed. Biomarker responses were not able to discriminate the different chemical contamination levels recorded in the Arcachon Bay and rather reflected changes in environmental factors. Furthermore, the strong intraspecies variability of biological responses could be due to genetic differences of mussels from the Arcachon Bay. It is the first time that such an integrated monitoring is performed in the Arcachon Bay, also taking into account seasonal variations of chemical contents and biomarkers levels in mussel tissues.     

Hydrocarbon Uptake by Roots of Vicia faba (Fabaceae)

Vicia faba was grown in crude oil polluted soil and its roots were extracted for the detection and estimation of hydrocarbons. Saturated and unsaturated Aliphatic Hydrocarbons (AHs) ranging from C₂₂ to C₃₆ were identified in AHs fraction. However, PAHs were not present in the same extract. This could be due to the fact that PAHs being toxic compounds are not accumulated in the plant root extracts of V. faba grown in crude oil polluted soil. Three phytoalexins were identified and estimated by mass spectrometric analysis in the root extracts of V. faba. These three compounds are 2-t-butyl-4-(dimethyl benzyl) phenol, 2, 4-bis (dimethyl benzyl) phenol and 2,4-bis (dimethyl benzyl)-6-butyl phenol. These phenolics in V. faba are being reported for the first time. These compounds are presumably elicited as a direct stress on crude oil hydrocarbons on the roots of this plant.     

Assessment of cyclodextrin-enhanced extraction of crude oil from contaminated porous media

The purpose of this study was to evaluate the effects of cyclodextrin (CD) on the extraction of Macondo well oil from contaminated porous media over a range of hydroxypropyl-β-CD (HPβCD) concentrations. To our knowledge, this is the first dataset on this type of CD yet assembled for an actual crude oil. The results showed that HPβCD can significantly increase oil extraction efficiency, demonstrated by increasing concentrations of all tested normal alkanes (nC(15)-nC(35)) and polyaromatic hydrocarbons (PAHs) in the aqueous phase with increasing CD concentration. A linear relationship between the extraction enhancement effect and CD concentration were verified experimentally and high correlation coefficients for total PAHs (R(2) = 0.82) and alkanes (R(2) = 0.99) were determined. For a 20% CD solution, 3.13 wt% of alkanes and 32.12 wt% of total PAHs were extracted to the aqueous phase, which was significantly more than what was extracted with water only (0.04% and 0.21% for alkanes and PAHs, respectively). This result shows that the remediation of oil contaminated media can be significantly enhanced through the use of HPβCD solutions in flushing or pump and treat operations to remove sorbed oil. The CD extraction enhancement effect decreases with increasing n-alkane chain length for the carbon number range tested. CD significantly enhanced PAH extraction from sand and the enhancement effect increased in the order of parent compounds < C-1 substituted < C-2 substituted < C-3 substituted for most PAHs tested. This study provides important information to assess the feasibility of using CD as a near-shore agent to enhance the cleanup of oil contaminated porous media.     

Gas chromatographic fingerprinting of crude oil from Idu-Ekpeye oil spillage site in Niger-delta, Nigeria

Samples were collected from an oil polluted site in Niger-delta, Nigeria. Gas chromatographic analyses carried out on the samples revealed an abundance of n-alkanes within the n-C₈–n-C₂₃ region. The pristane/phytane ratio of 5.70 obtained for the samples depicted a plant/terrestrial source input and a possible oxic depositional environment. The n-C₁₇/pristane and n-C₁₈/phytane ratios of 2.80 and 2.77, respectively, suggested that the spilled oil was only slightly weathered, as corroborated by the presence of peaks in the aromatic hydrocarbon fingerprints. The polycyclic aromatic hydrocarbon (PAH) fractions showed that the hydrocarbon fractions might have undergone combustion and/or that there was bush burning at the site prior to the oil spill incidence. This is supported by the abundance of high-molecular-weight PAHs which are pyrogenic in nature. High molecular weight PAHs are products of the combustion of petroleum or its products. The phenanthrene/anthracene ratio of 0.95, fluorathene/pyrene ratio of 2.23 and the ∑ (other three to six ringed PAHs)/∑ (five alkylated PAHs) ratio far greater than unity (4.10) also affirm this. On the other hand, the benzo (a) anthracene to chrysene ratio of 0.24 confirms the petrogenic origin of the spilled oil because chrysene which is highly abundant is a fossil PAH.     

Sediment Contamination, by Habitat, in the Tampa Bay Estuarine System (1993–1999): PAHs, Pesticides and PCBs

More than 760 Tampa Bay (Florida, U.S.A.) sediment samples have been analyzed for organic contaminants (PAHs, organochlorine pesticides, and PCBs) since 1993. Data were analyzed to assess status by habitat (defined by overlapping salinity zones and sediment type). The habitats most degraded by PAHs and pesticides were generally located in lower salinity, fine-grained sediment habitats, which are typically confined to the Hillsborough River. PCB contamination was more common in mesohaline waters of the Palm and Hillsborough rivers. Higher salinity portions of the bay, where medium to coarse sand-sized sediments predominate, showed little evidence of contamination by PAHs, PCBs and pesticides other than lindane.     

Effects of crude oil residuals on soil chemical properties in oil sites, Momoge Wetland, China

Crude oil exploration and production has been the largest anthropogenic factor contributing to the degradation of Momoge Wetland, China. To study the effects of crude oil on wetland soils, we examined the total petroleum hydrocarbon (TPH), total organic carbon (TOC), total nitrogen (TN), and total phosphorus (TP), as well as pH and electricity conductivity (EC) from oil sites and uncontaminated areas in the Momoge Wetland. All contaminated areas had significantly higher (p < 0.05) contents of TPH and TOC, but significantly lower (p < 0.05) TN contents than those of the uncontaminated areas. Contaminated sites also exhibited significantly higher (p < 0.05) pH values, C/N and C/P ratios. For TP contents and EC, no significant changes were detected. The level of soil contamination and impact of oil residuals on soil quality greatly depended on the length of time the oil well was in production. Oil residuals had caused some major changes in the soils’ chemical properties in the Momoge Wetland.