Operational considerations for field data collection of water and dust samples in the home

Abstract

Background: Epidemiological studies include water and dust samples to measure exposure to a variety of contaminants. These matrices are used because they are considered inexpensive and easy to collect. Aims: To examine the operational feasibility of collecting water and dust samples, the National Children's Study (NCS) Vanguard Study collected samples from the homes of participants in select study locations from the spring 2011 to the fall 2012. Methods: At the first pregnancy visit the following environmental samples were collected, a water pharmaceuticals sample, a water pesticides sample, and a bulk dust sample. The water samples were collected in one-liter plastic bottles with 50 mg ascorbic acid preservative. Three bottles were filled for the pharmaceuticals sample and two bottles were filled for the pesticides sample. Both water samples were collected from the kitchen tap after a five minute flush. The bulk dust sample was collected by obtaining the vacuum bag or the dust from the vacuum, wrapping it in aluminum foil, and placing it into a plastic bag. The samples were then taken to the study center in a cooler filled with ice packs, logged into the study sample tracking system, and stored at 4 oC (water) or -20 oC (dust). The water and dust samples were shipped for long term storage on ice packs and dry ice, respectively. At the repository, the water and dust samples were stored at 20 oC. Results: By September 2012, the NCS collected over 380 tap water pharmaceutical samples, over 370 tap water pesticide samples, and over 270 bulk dust samples. The response rates to the collections were all over 70 percent. Reasons samples were not collected include no vacuum in home and participant refusal. Conclusions: Although water and bulk dust samples are easy to collect, they are not without operational issues. Participants may not have vacuums; also, when an analysis method requires a large volume of water it can pose problems with transport, shipping, and handling.