Geology topics

Jared C. Smith

Publications and source records attributed to Jared C. Smith.

2 recordsLinked to original sources

USGS2023

Validation and standardization of SPE and HPLC-UV methods for simultaneous determination of legacy and insensitive munitions

There have been few attempts to consolidate legacy and insensitive munitions analyses. Furthermore, there are no standard methods for insensitive munitions (IM) in tissues, resulting in overlapping methods and supplementary analyses. The goal of the present study was to validate extraction and instrumental methods previously developed and address analytical methodology gaps (missing tissue matrices, combined legacy and IM analysis, and IM compounds). The method encompasses analytes in waters, soils, and tissues. The primary and secondary instrumental methodologies use high performance liquid chromatography-ultraviolet (HPLC-UV) and an alternate LC-mass spectrometry (MS) method, which includes 26 compounds of interest (legacy munitions, IM, IM degradation products , and other munitions compounds). The methods were formally evaluated during a series of double-blind round robin studies including a broad variety of laboratories (Government Department of Defense (DoD), Government non-DoD, ammunition manufacturing, commercial, and academic). The results of these round robin studies were gathered to generate recovery ranges for each of the 26 compounds in each of the matrices. The recovery ranges were subsequently compared with existing recovery ranges for standard explosives analysis, United States Environmental Protection Agency (USEPA) 8330B. The validation study reveals a capable method, which reduces analysis time for IM and legacy munitions analyses.

Environmental Nanotechnology, Monitoring & Managem↗

USGS2022

Salmonella enterica serovar Typhimurium from wild birds in the United States represent distinct lineages defined by bird type

Salmonella enterica serovar Typhimurium is typically considered a host generalist; however, certain isolates are associated with specific hosts and show genetic features of host adaptation. Here, we sequenced 131 S. Typhimurium isolates from wild birds collected in 30 U.S. states during 1978-2019. We found that isolates from broad taxonomic host groups including passerine birds, water birds (Aequornithes), and larids (gulls and terns) represented three distinct lineages and certain S. Typhimurium CRISPR types presented in individual lineages. We also showed that lineages formed by wild bird isolates differed from most isolates originating from domestic animal sources, and genomes from these lineages substantially improved source attribution of Typhimurium genomes to wild birds by a machine learning classifier. Furthermore, virulence gene signatures that differentiated S. Typhimurium from passerines, water birds, and larids were detected. Passerine isolates tended to lack S. Typhimurium-specific virulence plasmids. Isolates from the passerine, water bird, and larid lineages had close genetic relatedness with human clinical isolates, including those from a 2021 U.S. outbreak linked to passerine birds. These observations indicate that S. Typhimurium from wild birds in the United States are likely host-adapted, and the representative genomic dataset examined in this study can improve source prediction and facilitate outbreak investigation.

Applied and Environmental Microbiology↗