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1.
An important consideration of any commercial and industrial property acquisition or divestiture—whether it is a single gasoline station or a suite of oil refineries—is the extant environmental conditions of the property(s) at the time of the transaction. Property sellers and prospective buyers each consider and negotiate how any existing or future liability associated with extant environmental conditions will be handled. In spite of this forethought and the agreed contract terms, future litigation over unanticipated environmental contamination remains a real possibility. Often precipitating future litigation are disagreements surrounding whether “newly realized” contamination is old (pre-sale) or new (post-sale). As a result, environmental forensic investigations are often faced with the issue of “age-dating” this newly discovered contamination in order to determine whether it was released pre- or post-sale. Age-dating contamination can be an inherently difficult task to perform and technically defend. Technical arguments between experts can be short-circuited if there was an irrefutable understanding of the nature of extant contamination that had existed at the time of the sale. Conventional environmental due diligence investigations (Phase I and II site assessments) fall short of providing this understanding. In this paper, we discuss Strategic environmental baselining (SEB), a cost-effective and pro-active form of environmental due diligence that incorporates a key component of environmental forensics, that is, advanced chemical fingerprinting using modified EPA Methods that are tailored for hydrocarbon fingerprinting. Sufficient sampling and advanced chemical fingerprinting performed at the time of a transaction (or, at least, properly archived samples analyzed in the future as needed) provides the evidence that eliminates the need to “age-date” contamination at some future date. Advanced chemical fingerprinting data also provides detailed characteristics of the extant contamination and thereby, helps distinguish “old” from “new” contamination, regardless of alteration of the chemicals of concern by weathering. Armed with this information both buyers and/or sellers can protect themselves in the event of any future claim(s).  相似文献   

2.
In light of the strict legal scrutiny surrounding DNA typing at this time, it has become necessary to systematically address the issue of PCR contamination. To precisely define the parameters affecting PCR contamination under casework analysis conditions, PCR amplification reactions were intentionally compromised by employing sub-standard laboratory technique and by introducing secondary sources of DNA. The PCR parameters considered for potential sources of contamination include amplification set-up, amplification product handling, aerosol DNA and storage. In addition, analyst technique was evaluated by modifying or eliminating standard safeguards. Under the circumstances normally encountered during casework analysis, PCR contamination was never noted. Significantly, using the dot blot detection method, contamination was never observed when nanogram quantities of genomic DNA were mishandled or aerosolized. Contamination occurred only when amplification product was carelessly manipulated or purposefully sprayed near or directly into open tubes containing water or genomic DNA. Although standard precautions should be employed during PCR-based DNA typing, our data indicates that contamination during amplification procedures is not prevalent when detected by dot blot analysis.  相似文献   

3.
Nylon bags are used for packaging fire debris in several countries, particularly in Europe. The possibility of cross‐contamination during transport from the fire scene to the laboratory, in normal casework conditions in the U.K., was studied for two brands of nylon bags, using simulated heavy‐loaded fire debris. Three experiments were carried out with each brand, using as sample a piece of cotton fabric soaked with gasoline. One experiment was carried out using automotive paint thinner (oxygenated solvent). Each sample was sealed in a nylon bag and stored in contact with eight empty bags. The empty bags were analysed at regular intervals for a period of time up to 8 weeks, using SPME and GC/MS. Cross‐contamination was found for components of gasoline (toluene and C2‐alkylbenzenes) in the two brands of nylon bags used, after 4 days and 2 weeks. Cross‐contamination using automotive topcoat thinner was detected after 2 days.  相似文献   

4.
Detection of specific meningococcal capsular polysaccharide (CPS) in postmortem blood permits rapid diagnosis of meningococcemia and differentiation from pneumococcemia and septicemia caused by Haemophilus influenzae Type b. We present studies validating application of latex agglutination assay for CPS on blood samples collected at autopsy, delineate the circumstances when CPS testing is indicated, and illustrate the usefulness of this procedure by several recent cases. Blood samples from victims dying of injury or disease other than infection were examined to determine whether the postmortem interval, bacterial contamination, anticoagulants, or delay in testing would result in false positive assays. Series 1 samples, collected so as to minimize bacterial contamination, were immediately submitted for assay. Series 2 evaluated the effect of adverse conditions of collection, anticoagulation, and prolonged sample storage. Despite extended postmortem intervals of up to 14 days, heavy bacterial contamination, prolonged storage at 4 degrees C, deep hemolysis, and presence of anticoagulants, false positive assays were seldom observed.  相似文献   

5.
The procedure used in this laboratory for removing and identifying contamination of hair specimens with drugs is demonstrated by its application to hair contaminated by various experimental models. The models include soaking; coating with drug followed by sweat conditions for 6 h; and soaking in a very high concentration of cocaine followed by storage and multiple shampoo treatments. A multi-part wash procedure along with a wash criterion is applied to all samples containing drug above the cutoff. The failure of the wash criterion is a signal that the sample may be positive due to contamination rather than use, and in the absence of other over-riding evidence, the sample would be considered to be negative for drug use. This Wash Criterion has also been tested with hair from subjects demonstrated to be drug users by one or more drug-positive urines; in these studies, all hair samples from demonstrated users passed the Wash Criterion test.  相似文献   

6.
A sensitive radioimmunoassay for the detection of human hemoglobin in dried bloodstains for the purpose of forensic science species identification has been developed. Bloodstains from 13 animal species were tested and found to be negative for human blood. A minimum volume of 0.8 microL of fresh blood is required to produce sufficient stain for successful testing. Bloodstains prepared from newborn and sickle-cell bloods were determined to be human. Bloodstains ranging in age from 1 month to 6 years which had been maintained desiccated at 20 to 25 degrees C were also successfully tested. Positive results were obtained on human bloodstains stored at 24 degrees C with relative humidity ranging from 0 to 98% for a period of 3 weeks. Absolute counts per minute (CPM) decreased with increased humidity. Human bloodstains exposed to bacterial contamination (gram positive or negative species) under humid conditions for 2 weeks also tested positive. Bacterial contamination caused a decrease in CPM, but insufficient to result in an erroneous conclusion as to species of origin. Positive results were also obtained on human bloodstains stored for 6 weeks at various temperatures ranging from -16 to 37 degrees C. No significant decreases in CPM were noted for any of the temperature conditions described.  相似文献   

7.
物证鉴定中的物证污染问题   总被引:12,自引:5,他引:7  
物证污染是影响物证鉴定结果的最重要因素之一,它会损害物证鉴定结论质量甚至造成错误的鉴定结论。随着以法医DNA检验为代表的物证鉴定技术检验灵敏度的提高,物证污染出现的可能性及其造成的危害程度都显著增加。物证污染有多种形式和来源,可能发生在犯罪现场或实验室。采取适当的污染防范措施可以有效降低物证污染发生的可能性,及时监测和发现物证污染可以将污染造成的危害降到最低。  相似文献   

8.
In postmortem cases, a blood sample is frequently obtained by transthoracic (TT) puncture. The purpose of this study was to determine if, in traumatic death, blood samples collected by TT provided a valid sample for blood alcohol analysis. A retrospective study (1980–1986) was conducted to evaluate possible contamination of blood by GI alcohol in traumatic death cases. Out of 6000 cases reviewed, 19 cses with BACs >500 mg/dl were found and 8 of these cases involved traumatic death with GI laceration and/or transection. The results of this study support the hypothesis that blood samples from the 8 cases had been contaminated, resulting in a falsely elevated BAC. A transthoracic study (1987–1989) was conducted under controlled conditions, where blood alcohol content of TT blood samples was compared with samples collected from the intact heart chamber. Seven out of 28 cases of traumatic injury revealed trauma to the GI tract. The results showed that when GI traumatic injury occurs and unabsorbed ethanol is present in the stomach, contamination of TT blood samples occurs and artificially elevated BACs are obtained. It is recommended that, in cases of traumatic injury, heart blood samples from the intact heart chamber, as well as samples of additional biological fluids, be collected to rule out the possibility of contamination and to ensure that the BAC used for forensic interpretation is accurate.  相似文献   

9.
It has long been suspected that the illicit distribution of cocaine in the United States has led to a large‐scale contamination of the currency supply. To investigate the extent of contamination, 418 currency samples (4174 bills) were collected from 90 locations around the United States from 1993 to 2009. The extent of their cocaine contamination was quantitated via gas chromatography/mass spectrometry or liquid chromatography/mass spectrometry. The level of cocaine contamination was determined to average 2.34 ng/bill across all denominations ($1, $5, $10, $20, $50, and $100). Levels of cocaine contamination on currency submitted to the Federal Bureau of Investigation Laboratory in criminal cases over the 1993–2001 timeframe had significantly higher contamination than currency in general circulation. A mathematical model was developed based on the background survey that indicates the likelihood of drawing a bill in specific concentration ranges. For example, there is a 0.8349 likelihood that random bill will have contamination less than 20 ng.  相似文献   

10.
The analysis of DNA from archaeological human remains is plagued by a unique set of methodological problems concerning contamination with modern exogenous DNA. Through an original approach, we propose complementary methods to identify all potential sources of contamination and complete guidelines for the validation of ancient human sequences. The study presented was conducted on non-European human samples (Polynesian and Amerindian) which were collected with all precautions during excavation. This permitted us to distinguish without ambiguity authentic and contaminant sequences. The samples' origins and histories were perfectly known, allowing us to trace all potential contamination sources and to determine the efficiency of precautions followed during all steps of the study. The data obtained confirm that precautions taken during sampling effectively prevent contamination. However, we demonstrate that human contamination can also be introduced during genetic analyses even if all precautions are strictly followed. Indeed, numerous human contaminations were detected in template-PCR products and negative controls, resulting in a striking diversity of contaminant mitochondrial DNA sequences. We argue that this contamination partly derives from the primers. To our knowledge, no previous experiment has been performed to investigate primers as a possible source of human contamination despite the fact that this specific type of contamination poses a real problem in terms of validating ancient human DNA studies. Finally, we confirm that the detection of contaminants in negative controls is clearly related to the number of PCR cycles used. This study enhances our understanding of contamination processes and confirms that, in reality, an absolutely contamination-free situation cannot be obtained. As a consequence, we propose improvements to the guidelines usually followed in the field in order to take the highly probable contamination of PCR reagents, including primers, into account.  相似文献   

11.
Property owners are subject to potential environmental liability from a number of sources including strict statutory liability for remediation of contamination on their properties as well as liability for conditions within their buildings. These latent environmental risks are often exposed in the context of a transaction, redevelopment, or change of use. Commonly used due diligence protocols can avoid or mitigate many risks but owners need to be aware of the limitations and pitfalls of due diligence. In many circumstances, environmental insurance should also be considered as part of the overall environmental risk management strategy.  相似文献   

12.
As the sensitivity and discriminative power of DNA technology progressively improves, the ability to utilise trace DNA as evidence in forensic casework similarly increases. Along with increased sensitivity comes the prospect of detecting contaminating DNA, complicating the interpretation of profiles. This study aimed to provide data into the occurrence and level of DNA potentially transferred between high risk vectors (scissors, forceps, gloves) and exhibits during the examination process in both light and heavy contamination/contact scenarios. DNA transfer was observed for all vectors in both transfer situations, with heavy conditions transferring more than light. Profiles with sufficient alleles to identify the origin were observed for each vector in both heavy and light scenarios, excluding forceps, where only a small number of alleles were transferred under light conditions,  相似文献   

13.
我国土壤污染防治立法研究   总被引:2,自引:0,他引:2  
罗吉 《现代法学》2007,29(6):99-107
我国目前在土壤污染防治方面不仅没有专门性单行法律、法规,而且在《环境保护法》等法律、法规中也只有些零散规定,防治土壤污染的法律基本上是一项空白,缺乏系统的、可操作性的具体法律制度。立法的缺乏直接导致环境管理权的缺乏,这与土壤污染的严峻形势及其防治的实际需要很不相适应,在土壤污染防治问题的原因分析中,几乎都将政策与法律的缺失问题作为最主要原因之一。为了使土壤污染防治有法可依,需要健全和完善土壤污染防治法律、法规体系,目前,最亟需制定的是一部综合性的土壤污染防治的法律,对我国土壤污染防治的目的、基本原则、管理体制和主要制度作出规定。  相似文献   

14.
法医DNA实验室的DNA污染和防范   总被引:3,自引:2,他引:1  
陈松 《刑事技术》2007,(3):16-20
DNA污染是产生DNA鉴定结论错误的重要因素,法医DNA实验室要努力去解决这一问题。DNA污染有自身污染、交叉污染、PCR污染3种。法医DNA实验室要采取实验室分区、严格检验操作步骤、对试剂及消耗材料进行质量控制等方法防止发生DNA污染,采取设置对照样本、核查DNA结果、建立DNA排查数据库等方法监测和发现DNA污染。  相似文献   

15.
Because contamination is usually tube-specific, negative controls cannot give assurance that an associated batch of extracted casework material is contaminant-free. However, it is possible to use them to predict the level of overall (undetected) contamination that is processed by an operational DNA unit. A MATLAB-based program was used to combine results of negative controls with actual casework DNA profiles to assess the probability that laboratory contaminants will give rise to reportable profiles (along with their likelihood ratios). Using data from an operational DNA unit as an example, it was demonstrated that the risk is inextricably linked to guidelines used to interpret DNA profiles. We have demonstrated how computer-based models can predict the levels of contamination expected in the process and, in addition, how the process can be made more robust by changing reporting guidelines. There is a need to compare DNA profiles against staff and plasticware elimination databases in order to determine sources of contamination. The likeliest outcome of a contamination event is false exclusion.  相似文献   

16.
Bank of England banknotes sampled from different locations in the UK have been analysed for the presence of cocaine, diamorphine (DAM), Delta(9)-tetrahydrocannabinol (THC) and 3,4-methylenedioxymethamphetamine (MDMA). A database of the contamination detected is routinely used as a benchmark against which the contamination detected on seized banknotes can be compared. Evidence presented at court details how banknotes seized from a suspect may differ from banknotes in general circulation in terms of their contamination with controlled drugs. A question arising from such evidence is whether seized banknotes could have become contaminated through being in circulation in drug "hot spots". In order to address this issue, a Plackett-Burman experimental design was used to investigate the influence of source location and other factors on banknote contamination with drugs of abuse. Banknotes were drawn from banks in eight regions throughout the UK. Each location could be described by a unique combination of the factors under investigation, namely whether the location was rural or urban, in the North or South of the UK, and whether it was a port of entry. The socio-economic class and the proportion of drug offenders in the area and the denomination of the banknotes were also considered as potentially influential factors. Indices were calculated to describe the degree to which samples were contaminated with different drugs, and normal probability plots were used to identify the factors that could account for the contamination observed. Whilst some factors were more influential than others, it was shown that, at the 95% confidence level, none of the proposed factors were significant influences on the contamination. Cocaine contamination on banknotes has been shown to follow a log-normal distribution. It was, therefore, possible to calculate F- and t-statistics to compare the cocaine contamination on the entire sample set with that detected on a second sample set consisting of banknotes all drawn from a single bank branch. It was shown that both inter-bank samples and intra-bank samples had similar variance and similar contamination levels at the 95% confidence level. This suggests that there are no significant regional trends in the contamination of banknotes with drugs of abuse across the UK.  相似文献   

17.
This paper analyzes the legal issues surrounding defendants' liability for property value diminution caused by stigma from environmental contamination. The courts, law review articles, and public policy analyses are in disagreement over how to handle stigma damages. This paper argues that a reasonable risk of contamination is not required for a nuisance claim if community effects, which were caused by the contamination, are present. The authors then turn to issues regarding the level of damages and propose a methodology for measuring compensation that is based on a guaranteed sales price. This methodology is applied to the RSR smelter in Dallas, Texas.  相似文献   

18.
The presence of gunshot residues (GSRs) on arrested suspects can help the Court to form an opinion regarding the possibility of utilization of firearms by these suspects. Since the presence of a few particles can in some cases already have a strong indicative value, the GSR experts have to evaluate in their daily work the risk of a potential contamination of these suspects during their arrest. A few studies conducted on police officers and police facilities concluded that the risk of secondary transfer on arrested suspects is quite negligible. However, the case of special force units of the police should be taken into account, since these units can be assumed to be highly contaminated by GSR due to their intensive training. The aim of this study is to evaluate this possibility of particle transfer by performing simulations of arrests by special force police units, according to both low and high contamination scenarios. The results show that secondary transfers of GSR during these simulations are in most cases not negligible, even for the low contamination scenario. This is especially apparent on the vests of the target persons, with an average of 7 GSR particles (2 PbBaSb and 5 TiZn) found on the stubs used on these materials. Of course, the major contamination levels were observed in the case of the high contamination scenario, due to the use of highly contaminated gloves by the police officers during the arrests. Some recommendations are proposed to take into account this risk of contamination and to try to minimize it, or at least to better identify it.  相似文献   

19.
Active cocaine use results in sequestration of parent drug in hair. In addition, hair has unique physicochemical properties that permit absorption of cocaine from the environment. When hair is tested for evidence of cocaine, it is important to consider whether the positive test resulted from active drug use or environmental contamination. In a series of laboratory experiments, it was found that exposure of ‘cut’ hair to cocaine vapor (‘crack’ smoke) and to aqueous solutions of cocaine hydrochloride resulted in significant contamination of hair samples. Similar results were obtained with two subjects who were exposed to cocaine vapor in an unventilated room. The amount of contamination adsorbed by hair depended upon both time and extent of exposure. Washing the hair samples with methanol removed >70% of the cocaine contaminant after cocaine vapor exposure, but was less effective (<50%) following contamination with aqueous cocaine. Shampoo treatment cycles (overnight soaking) progressively removed increasing amounts of cocaine from the contaminated hair, but residual cocaine remained after 10 cycles. Studies were also performed to determine the usefulness of benzoylecgonine as a marker of active cocaine administration. Small amounts of benzoylecgonine (ca. 1 ng/mg) were formed in hair as a result of environmental contamination with cocaine. Also, it was found that benzoylecgonine could be adsorbed from illicit cocaine contaminated with benzoylecgonine. It was concluded that positive hair test results should be interpreted cautiously due to the possibility of environmental contamination from cocaine and related constituents.  相似文献   

20.
Environmental surface sampling is crucial in determining the zones of contamination and overall threat assessment. Viability retention of sampled material is central to such assessments. A systematic study was completed to determine viability of vegetative cells under nonpermissive storage conditions. Despite major gains in nucleic acid sequencing technologies, initial positive identification of threats must be made through direct culture of the sampled material using classical microbiological methods. Solutions have been developed to preserve the viability of pathogens contained within clinical samples, but many have not been examined for their ability to preserve biological agents. The purpose of this study was to systematically examine existing preservation materials that can retain the viability of Bacillus anthracis vegetative cells stored under nonpermissive temperatures. The results show effectiveness of five of seventeen solutions, which are capable of retaining viability of a sporulation deficient strain of B. anthracis Sterne when stored under nonrefrigerated conditions.  相似文献   

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