Four prototype thin film oil samplers were evaluated for use in sampling for identification purposes. All of the samplers utilize an oenophiles sorbet as the collecting medium for the oil. In addition, two of the samplers also utilize a surfactant as an aid in collecting the oil. The sorbet materials used were chosen on the basis of their affinity for oils of all types.
Although these sorbents have been used previously in oil recovery systems, their use in an oil sampling system whose objective is identification of the oil sampled, required that an extensive series of tests be conducted. This series of tests, which is the subject of this paper, was conducted in two phases. The first phase was concerned with the operational aspects of the samplers (deployment, retrieval, cleaning, refurbishment, storage, etc.). The result of this phase is a table giving an evaluation of the samplers operational characteristics as observed during deployment from a boat on soybean oil slicks.
The second phase was concerned with the efficiency of the samplers on different oils and at different thickness, as well as the ability of the samplers to maintain the chemical integrity of the samples. Tests conducted during this phase included deployment of the samplers in slicks of known thicknesses. Three different oils were used during this phase: a No. 2 Fuel Oil, a South Louisiana Crude and a Bunker C. The efficiencies were calculated by color comparison of extracts with known volumes of solvent and standards of known oil concentration. The techniques used to evaluate the samplers' ability to maintain the chemical integrity of the sample include gas chromatgraphy, ultraviolet fluorescence and infrared spectrophotometer.
The four samplers were evaluated in order to assess the feasibility of adapting one or more of them for use from a vessel by Coast Guard field units. The samplers are intended for use on thin slicks where a sample is to be taken for identification purposes.
The objectives of the test was to evaluate:
Handling characteristics under practical conditions
Maintenance and repair requirements
Efficiency of oil pickup
Ability of samplers to maintain the chemical integrity of the oil
Three of the samplers tested were developed for the Coast Guard under contract; the fourth sampler was developed in house by the Coast Guard Research and Development Center. Figure 1 shows relative size differences between samplers; from the top, clockwise, are Shell, R&D Center, Poseidon Mod 1 and Mod 2 (with container), and Marconsult samplers.
The basic Poseidon Oil Net is a polypropylene yarn double layered sleeve held open at the mouth by a steel hoop and knotted at the tail. The net is bridled at the mouth and tied to a boat hook for deployment. The polypropylene yarn serves as both the oil sorbent and the supporting net material.
The Mod 2 net is identical to the basic Poseidon Mod 1 net except for three small differences.