1.1 This guide describes the procedures for obtaining and interpreting data associated with a direct health status assessment for mammalian receptors at chemically contaminated terrestrial sites where ERA work is either scheduled or ongoing, and irrespective of the number and type of chemicals that may be present. Through reviewing sperm features, the RSA method reports on the reproductive health of male rodents in their natural environmental settings, with these animals serving as surrogates for other (and larger) site mammals (4).

1.2 These procedures are applicable at any terrestrial property that supports small mammals (for example, mice, voles, rats, squirrels) and has contaminated soil. Importantly, chemicals of concern in site soils need not be spermatoxins. Additionally, the RSA method considers that any combination of chemicals or other site stressors might collectively act to compromise reproduction, held to be a sensitive toxicological endpoint for mammals. The anticipated primary application of the method will be at historically contaminated sites (such as Superfund sites). The procedures describe tasks conducted in the field and in a laboratory. For the latter, tasks may be conducted either in an on-site mobile laboratory, or in a more conventional laboratory setting. For certain tasks, a make-shift work space may be suitable as well (see 7.3).

1.3 Initial determinations of compromised or non-compromised reproduction in resident male small rodents are made through a cautious comparative review of sperm parameters. Briefly, for the rodents of a given species collected at both a contaminated site and a habitat-matched (non-contaminated) reference location, arithmetic means are first computed for each of the three sperm parameters of count, motility, and morphology. If one or more of the parameter means of the contaminated site rodents reflect an unfavorable shift (that is, count or motility is less than that of reference location animals; the percentage of abnormally-shaped sperm is greater relative to reference location animals), the percent decrease or increase in each mean is compared to the relevant established sperm parameter benchmark, each in the form of that degree of shift in an unfavorable direction that signifies lesser reproductive success (2) (see 9.3).

1.4 Advanced determinations of compromised or non-compromised reproduction in larger site-contacting mammals, the true focus of the RSA method and this guide, are made through an applied spatial movements-based extrapolation scheme. Where established sperm parameter benchmark exceedances are not observed in contaminated-site rodents, other mammals contacting a site are also assumed to have non-compromised reproduction. This follows from the latter all having notably lesser degrees of site exposure due to home ranges that are vastly larger than those of rodents. By way of example, with respective home ranges of 400+ and 640 acres for the red fox and white-tailed deer (10-14), these species would spend minimal amounts of their time (for example, 5 %) at prototypical contaminated sites that cover areas of 25 acres or less (15, 16). Where one or more sperm parameter benchmarks are exceeded in contaminated-site rodents (certainly indicating that the rodents are reproductively compromised), other site mammals may also be reproductively compromised. The greater the disparity between the home ranges of the target species (that is, the site rodent) and any of the other mammals known to contact the contaminated site in question, the less likely it will be that the latter are reproductively compromised. The RSA method employs the same toxicological extrapolation principles as that used for mammals in conventional desktop-based ERAs. In those ERAs, stressor-mediated responses of rodents (of a laboratory-based study) assist with the interpretation of health effects for an expanded list of mammals that cannot conveniently be evaluated directly for health status (for example, fox, skunk, raccoon, deer, coyote, etc.).

1.5 This guide is arranged as follows:

1.6 This 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.