Miljöskydd: allmänt

This document provides guidance on taking and handling samples that are collected as part of an investigation into the likely source of a crude oil or petroleum product spill into a marine or aquatic environment. Guidance is given on taking samples from both the spill and its potential source.
Mostly, oil sampling is part of legal procedures and has to be treated like any other preservation of evidence (legal sampling).
WARNING - Taking samples may involve hazardous materials, operations and equipment.
This document is not intended to address all the safety and health aspects associated with the guidance given. It is the responsibility of the user to consult and establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
IMPORTANT - Most countries have special trained teams to take samples on board of ships. As police officer or law enforcer, don’t take unnecessary risks and ask assistance from such a team when available.
NOTE For the sake of clarity, the word ‘oil’ is used throughout this document. It can equally refer to crude oil, a petroleum product or mixtures of such.

This document describes a method to firstly identify the specific nature of oils spilled in the environment and secondly compare the chemical composition of samples from spilled oil with those of suspected sources. Specifically, the document describes the detailed analytical methods and data processing specifications for identifying the specific nature of oil spills and establishing their correlation to suspected sources. Even when samples or data from suspected sources are not available for comparison, establishing the specific nature (e.g. refined petroleum, crude oil, waste oil, etc.) of the spilled oil can still help to constrain the possible source(s) of the spilled oil.
This methodology is restricted to petroleum related products containing a significant proportion of hydrocarbon-components with a boiling point above 150 °C. Examples are: crude oils, higher boiling condensates, diesel oils, residual bunker or heavy fuel oils, lubricants, and mixtures of bilge and sludge samples, as well as distillate fuels and blends. While the specific analytical methods may not be appropriate for lower boiling oils (e.g. kerosenes, jet fuels, or gasoline), the general concepts described in this methodology, i.e. statistical comparison of weathering-resistant diagnostic ratios, can have applicability in spills involving this kind of oils.
Paraffin as petroleum product (for candles, etc.) is outside the scope of this method, because too many compounds have been removed during the production process [37]. Still the method can be used to analyse the type of product involved.
This method is not directly intended for identifying oil spills in matrixes like groundwater, vegetation, wildlife/tissues, soils, or sediments, and although its application in these matrices is not precluded, it requires caution. The reason for caution is that the extractable compounds in these matrices may alter and/or contribute additional compounds compared to the source sample, which if left unrecognised, can lead to “false non-matches”. It is therefore advisable to analyse background sample(s) from seemingly uncontaminated matrix. Including these “non-oil” matrices in this oil spill identification method can require additional sample preparation (e.g. clean-up) in the laboratory prior to analysis and consideration of the extent to which the matrix can affect the correlation achieved. Evaluating the possible effects in these matrices is beyond the scope of this document. Whether the method can be used for this kind of matrices may depend on the oil concentration compared to the “matrix concentration” of the samples. In matrices containing relatively high concentration of oil, a positive match can still be concluded. In matrices containing relatively low concentration of spilled oil, a false non-match or an inconclusive match could be achieved due to matrix effects.