Critically assessing the utility of portable lead analyzers for wildlife conservation: Portable Lead Analyzers

Lead (Pb) exposure in wildlife is a widespread management and conservation concern. Quantitative determination of Pb concentrations in wildlife tissues is the foundation for estimating exposure and risk. Development of low-cost, portable instruments has improved access and cost-effectiveness of determining Pb concentrations in blood samples, while also facilitating the ability for wildlife researchers to conduct near real-time Pb testing. However, these instruments, which use anodic stripping voltammetry (ASV) methodology, may produce an analytical bias in wildlife-blood Pb concentrations. Additionally, their simplicity invites use without appropriate quality-assurance-quality-control measures. Together, these factors can reduce data quality and hamper the ability to evaluate it, raising concerns about use of these instruments to inform important conservation issues. We document the extent to which this bias is addressed in the wildlife toxicology literature, develop quantitative approaches for correcting the bias, and provide recommendations to ensure robust data quality when using these instruments. Of the 25 studies we reviewed that referenced ASV use for determining Pb exposure in wildlife, only 32% acknowledged the existence of bias from the instrument. Importantly, another 20% of the studies actually reported ASV and spectroscopic-based results together without acknowledging their lack of equivalence. Using a multispecies data set of avian blood Pb concentrations, we found that ASV-based estimates of paired blood Pb concentrations were 30-38% lower than those from standard spectrometric-based methods. We provide regression equations based on this analysis of 453 blood samples to allow users of ASV instruments to adjust Pb concentrations to spectrometric-equivalent values, and propose a series of guidelines to follow when using these instruments to improve data validity. Published 2018. This article is a U.S. Government work and is in the public domain in the USA.