IntroductionCarbon dioxide removal (CDR) is a necessary component of limiting global warming to 2 °C by 2,100. Marine enhanced rock weathering (mERW) with minerals like olivine is a CDR strategy with the potential to capture atmospheric carbon dioxide and mitigate ocean acidification, which threatens calcifying organisms including those essential for global aquaculture such as oysters. mERW could benefit these species through the local addition of alkalinity, although olivine also releases trace metals like nickel which may bioaccumulate.MethodsThis study presents findings from the world’s first field trial of mERW conducted in New York, USA. Olivine sand was applied to an intertidal beach, where juvenile oysters were exposed over a one-year period. Oyster biomass and trace metal accumulation were subsequently assessed.ResultsOn short (2 month) timescales, Eastern oysters exposed to olivine demonstrated a positive, but non-significant, increase in biomass as compared to control treatments. After a year of exposure, there was no significant difference in oyster biomass or mean metal accumulations between olivine and control treatments (mean for all treatments 2.18 ± 2.71 μg g dw−1 for Ni; <1 μg g dw−1 for Cr and Co).DiscussionMetals concentrations were below US Food and Drug Administration warning thresholds and within global natural ranges. Our findings suggest that mERW with olivine has a limited effect on oysters and that olivine-derived metals did not result in oyster safety concerns for human health.