Photo-oxidation and Photo-toxicity of Crude and Refined Oils

The fate and effects of an oil spill are effected by solar radiation through the action of photo-oxidation and photo-toxicity. Photo-oxidation, an important process in the weathering of oil, produces a variety of oxidized compounds, including aliphatic and aromatic ketones, aldehydes, carboxylic acids, fatty acids, esters, epoxides, sulfoxides, sulfones, phenols, anhydrides, quinones and aliphatic and aromatic alcohols. Some of these compounds contribute to the marine biota toxicity observed after an oil spill. Photo-toxicity occurs when uptake of certain petroleum compounds, e.g. certain polycyclic aromatic hydrocarbons and benzothiophenes, is followed by solar exposure which results in much greater toxicity than after dark uptake. The mechanism of PAH photo-toxicity includes absorbance of solar radiation by the PAH which produces a free radical and this free radical in turn reacts with oxygen to produce reactive oxygen species that can damage DNA and other cellular macromolecules. While most studies on photo-toxicity have been carried out in the laboratory, there are studies showing that water from an oil spill is photo-toxic to bivalve embryos for at least a few days after the spill. Other studies have found that oil contaminated sediments are photo-toxic to several marine invertebrates. More studies are required to determine if marine fauna at an oil spill site are effected by the action of photo-toxicity and photo-oxidation.     

Biodegradation of Crude Oil Contaminating Marine Shorelines and Freshwater Wetlands

This paper is a summary of the various factors influencing weathering of oil after it has been released into the environment from a spill incident. Special emphasis has been placed on biodegradation processes. Results from two field studies conducted in 1994 and 1999 involving bioremediation of an experimental oil spill on a marine sandy shoreline in Delaware and a freshwater wetland on the St. Lawrence River in Quebec, Canada have been presented in the paper.     

In-situ Treatment of Oiled Sediment Shorelines

Experimental oil spill studies were conducted to quantify the effectiveness of selected in-situ shoreline treatment options to accelerate natural oil removal processes on mixed-sediment (sand and pebble) shorelines. At each of three distinct shoreline sites, treatment test plots and control plots were established within a 40-, 80- and 143-m continuous stretch of oiled shoreline. A total of 5500 l of oil was deposited along a 3-m wide swath in the upper intertidal zone at each site. Approximately one week after oiling, a different treatment technique was applied to each plot. The treatment techniques were: sediment relocation (surf washing), mixing (tilling), bioremediation (fertilizer application), and bioremediation combined with mixing. One plot at each site was monitored for natural attenuation. The quantity of oil removed from the plots was measured six times up to 60 days post-treatment and then again one year later. Changes in the physical character of the beach, oil penetration, movement of oil to the subtidal environment, toxicity, and biodegradation were monitored over the 400-day period.The results verified quantitatively that relocation of oiled sediments significantly accelerated the rate of oil removal from the shoreline by more than one year. Microscopic observations and image analyses confirmed that the oil-mineral aggregate formation process was active and was increased by sediment relocation. Oil biodegradation occurred in this arctic environment, both in the oiled sediments and on the fine mineral particles removed from the sediment by natural physical processes. The biodegradation of oil in sediment was significantly stimulated by simple bioremediation protocols. Mixing (by tilling) did not clearly stimulate oil loss and natural recovery in the context of this experimental design. None of the treatment techniques elevated toxicity in the nearshore environment to unacceptable levels, nor did they result in consequential alongshore or nearshore oiling.     

Estimating Time Windows for Burning Oil at Sea: Processes and Factors

This paper discusses processes and factors for estimating time period windows of in situ burning of spilled oil at sea. Time-periods of in situ burning of Alaska North Slope (ANS) crude oil are estimated using available data. Three crucial steps are identified. The First Step is to determine the time it takes for the evaporative loss to reach the known or established limitation for evaporation and compare this time-period with estimated time of ignition at the ambient wind and sea temperatures. The Second Step is to determine the water up-take of the spilled oil and compare it with the known or established limitation for water-in-oil content. The Third Step is to determine the necessary heat load from the igniter to bring the surface temperature of the spilled oil to its flash point temperature so that it will burn at the estimated time period for ignition of the slick.     

油气田开发对生态环境的影响--以昌吉州为例

重点论述了昌吉州周围油气田开发对大气、水、噪声、土壤环境及生态环境造成的影响，尤其是对生态环境的影响作了重点阐述，这对做好油气田环境保护工作具有一定的指导意义。     

国外石油天然气开采行业清洁生产技术发展动态

对比和分析了各国或国际组织关于清洁生产含义的不同解释方法,阐述了石油天然气开采行业清洁生产的基本概念。在此基础上,按照物探、钻井、井下作业(包括试油、酸化及酸压、压裂、修井)、采油及采气生产几个工艺环节,对国际上石油天然气开采行业清洁生产最新技术进行了详细总结和分析。针对我国相关行业的清洁生产水平,提出了实用有效的技术发展对策和建议。     

Volatilization behaviors of diesel oil from the soils

The volatilization of diesel oil, Shengli crude oil and 90 # gasoline on glass surface of petri dishes were conducted at the ambient temperature of 25℃. Diesel oil evaporates in a power manner, where the loss of mass is approximately power with time. 90 # gasoline evaporates in a logarithmic with time. Where as the volatilization of Shengli crude oil fit either the logarithmic or power equation after different time, and has similar R^2 . And the effects of soil type and diesel oil and water content on volatilization behavior in unsaturated soil were studied in this paper. Diesel oil and water content in the soils play a large role in volatilization from soils. Appropriate water helps the wicking action but too much water stops it. The wicking action behaves differently in four different types of soils in the same volatilization experiment of 18% diesel oil content and air-dry condition.     

油气田建设水土保持措施体系研究

文章对西南地区典型油气田建设工程水土保持措施的类型、工程量进行数理统计,监测评估水土保持措施体系的实施效果,对不同的工程单元分区利用多元相关分析方法,研究水土保持措施与实施效果之间的线性关系,进一步提出不同类型水土保持措施的优先等级。结果表明：当前油气田建设过程中,工程措施使用频率最高,植物措施与临时措施对水土保持效果最为显著。为西南油气田建设工程水土保持措施制定和实施提出指导性建议。     

Chirp浅剖仪在水域地质调查中的应用

基于线性调频技术的Chirp声学浅剖仪系统,较好地解决了探测深度以及分辨率这两个最令人关心但又互为矛盾的问题。该浅剖仪系统主要由导航系统、信号控制系统、信号发射系统、信号接受系统以及测深系统等5部分组成,理论上,其纵向地层分辨率为十几厘米左右,最大探测深度在百米左右,具体视地层以及水质等条件而定。考虑到该系统的特殊性和复杂性,对其关键操作进行了较为详细的描述。最后介绍了该系统在活断层调查、管线走向调查以及水底抛石调查等不同类型水域岩土工程勘察中的成功应用,表明其具有良好的应用前景。     

Bio-herbicidal effects of five essential oils on germination and early seedling growth of velvetleaf (Abutilon theophrasti Medik.)

The evaluation of the inhibition effect exerted by the essential oils of basil (Ocimum basilicum), sage (Salvia officinalis), thyme (Thymus vulgaris), lemon balm (Melissa officinalis) and goldenrod (Solidago virgaurea) on seeds germination and early seedling growth of velvetleaf (Abutilon theophrasti Medik.) weed was examined in a laboratory bioassay. The essential oils were obtained by hydrodistillation and characterized chemically by gas chromatography coupled with both mass spectrometry and flame ionization detector. The working solutions of essential oil emulsified with Tween 20 and dissolved in distilled water were prepared at three concentration levels (0.01%, 0.1% and 1%, vol/vol). The results obtained showed that increase of essential oil concentration leads to decrease of seed germination, shoot and radical length of velvetleaf. The obtained data revealed a highly significant effect (P?<?0.05) between control and 1% and 0.1% oil concentrations in all treatments. The essential oils of basil, thyme and lemon balm exhibited more powerful bio-herbicidal effect compared to sage and goldenrod essential oils on the germination and early seedling growth of velvetleaf weed.