ASTM D7144-05a

Human exposure to toxic metals present in surface dust can result from dermal contact with or ingestion of contaminated dust. Also, inhalation exposure can result from disturbing dust particles from contaminated surfaces. Thus standardized methods for the collection and analysis of metals in surface dust samples are needed in order to evaluate the potential for human exposure to toxic elements.

This practice involves the use of sampling equipment to collect surface dust samples that may contain toxic metals, and is intended for use by qualified technical professionals.

This practice allows for the subsequent determination of collected metals concentrations on an area (loading) or mass concentration basis, or both.

Because particle losses can occur due to collection of dust onto the inner surfaces of the nozzle, the length of the collection nozzle is specified in order that such losses are comparable from one sample to another.

This practice is suitable for the collection of surface dust samples from, for example: (a) soft, porous surfaces such as carpet or upholstery; (b) hard, rough surfaces such as concrete or roughened wood; (c) confined areas that cannot be easily sampled by other means (such as wipe sampling as described in Practice D 6966). A companion sampling technique that may be used for collection of surface dust from hard, smooth surfaces is wipe sampling (Practice D 6966). A companion vacuum sampling technique that may be used for sampling carpets is described in Practice D 5438.

Procedures presented in this practice are intended to provide a standardized method for dust collection from surfaces that cannot be reliably sampled using wipe collection methods (for example, Practice D 6966). Additionally, the procedure described uses equipment that is readily available and in common use for other environmental and occupational hygiene sampling applications.

The entire contents of the filter holder, that is, the filter plus collected dust, is targeted for subsequent analysis for metals content. An internal capsule is used if gravimetric analysis is necessary.

1.1 This practice covers the micro-vacuum collection of surface dust for subsequent determination of metals. The primary intended application is for sampling from soft, rough, or porous surfaces.

1.2 Micro-vacuum sampling is carried out using a collection nozzle attached to a filter holder (sampling cassette), which is in turn connected to an air sampling pump.

1.3 This practice allows for the subsequent determination of metals on a loading basis (mass of metal(s) per unit area sampled), or on a concentration basis (mass of metal(s) per unit mass of sample collected), or both.

1.4 The values stated in SI units are to be regarded as the standard.

1.5 Limitations—Due to a number of physical factors inherent in the micro-vacuum sampling method, analytical results for vacuum dust samples are not likely to reflect the total dust contained within the sampling area prior to sample collection. Indeed, dust collection will generally be biased towards smaller, less dense dust particles. Nevertheless, the use of this standard practice will generate data that are consistent and comparable between operators performing micro-vacuum collection at a variety of sampling locations and sites.

1.6This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.