Earthworms as soil quality indicators: A case study of Crissy Field and Bayview Hunters Point naval shipyard

Crissy Field (CF) and Bayview Hunters Point (BVHP) are both former military sites in San Francisco, California, USA, where chemical disposals occurred. Although CF, a former air coast defense station, was formally remediated in 1994, leading to low topsoil chemical remains, only haphazard remediations of BVHP, a former naval shipyard, occurred. Worms live in topsoil, and their health reflects that of their environment, thus indicating the health of other organisms who live on and around that soil, including humans. To investigate the differences in topsoil quality between CF and BVHP, topsoil toxicity was analyzed by taking soil samples along with Lumbricus terrestris (earthworm) counts. Topsoil sampling revealed heavy metals that influence human health, including arsenic, lead, chromium, and mercury. We hypothesized that fewer L. terrestris would be observed in BVHP and that BVHP would test positive for more heavy metals than CF. Our results aligned with our hypotheses as higher levels of contaminants and fewer worms were detected in BVHP topsoil compared to CF, underlining the need to remediate the soils of BVHP naval shipyard. Our findings support the poor ecological health and viability of BVHP topsoil and the dangers it poses, along with supporting claims surrounding illnesses attributed to BVHP toxins.