Sampling plans are not necessarily lengthy documents. The exceptions occur with spills of light oils, which can penetrate surface soils or sediments and travel through the subsurface, or with underground spills from tanks or pipelines. Sampling on land is less of a concern as source identification is, in most cases, straightforward. This section describes elements of designing an adequate sampling plan for spills of a known source, with a primary focus on the options of discrete water sampling, continuous water sampling, and oil source sampling. Also integral to this type of spill investigation is the characterization of the pre-existing “background” conditions in the area of the spill. For spills with a known source, sampling is still integral to determination of the spill pathway and to scaling the nature of the problem in terms of the type, amount, and extent of the spilled material(s). spills with a known sourceĪs part of the site characterization of a forensic oil spill investigation, an appropriate sampling plan must be designed and implemented. Parker, in Standard Handbook Oil Spill Environmental Forensics (Second Edition), 2016 1.7 Sampling plan and design: 1. Spill site characterization in environmental forensic investigationsĮd H. Incorrect application can result in regulatory observations ( Fig. Therefore, it is very important to properly interpret the standard and apply the inspection rules as they are prescribed. The common mistakes include, but not are limited to, the selection of incorrect sampling size, selection of incorrect acceptance criteria, or an attribute plan used for variable data, etc. The standard provides instructions as to how it is supposed to be applied however, this is often misinterpreted. The use of sampling tables provides a quicker way of selecting a sampling plan instead of developing a sampling plan using complex statistics. ANSI/ASQ Z1.4-2008: Sampling Procedures and Tables for Inspection by Attributes is an acceptance sampling system that provides tightened, normal and reduced plans to be applied to attributes for inspection for the percentage of nonconformities per 100 units. It is a common pharmaceutical industry practice to employ American National Standards Institute (ANSI)/American Society for Quality (ASQ) Z1.4-2008: Sampling Procedures and Tables for Inspection by Attributes for inspection of product/process defects. Attribute sampling plans are often used to inspect the effectiveness of the product/process and to determine the rate of compliance with established criteria.
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