There were two main objectives to this study: (1) to
determine if microplastics were present in Manila clams
from Baynes Sound, BC, and (2) to investigate differences
in microplastic concentrations between wild and cultured
clams. This study has documented microplastic presence in
Manila clams from the Northeast Pacific Ocean that are
consumed by humans. While concentrations in individual
clams ranged from 0.07 to 5.5 particles/g, every clam had
at least one microplastic item found within. This may be
due to contamination in some cases, but overall these data
suggest that microplastics have become ubiquitous and can
enter the food chain at the benthic bivalve level.
Microplastic presence in the Northeast Pacific Ocean has
been relatively understudied, despite concern from residents.
Desforges et al. (2014) have documented high fiber
content (*3000 particles/m3) in waters surrounding Vancouver
Island, particularly in nearshore regions of the Strait
of Georgia where Baynes Sound is located. Additionally, it
is now clear that microplastics can enter the marine food
web via zooplankton ingestion or entanglement (Desforges
et al. 2015), but until now other routes of entry to food
webs were unknown. In Baynes Sound specifically, Cluzard
et al. (2015) documented concentrations of 0.045
microplastic particles/g (w/w) of sediment. Bivalves in the
Northeast Pacific Ocean may be ingesting microplastics
originating from both the water column and sediments, but
detailed water sampling in Baynes Sound would provide
insight into relative concentrations between water and
sediment.