Contaminant concentrations and risks associated with the Pacific oyster in the highly urbanized San Diego Bay

Contaminant Risk and Social Vulnerability Associated with Crustacean Shellfish Harvest in the Highly Urbanized San Diego Bay, USA

“…For example, phosphate flame retardants and pyrethroids were at higher levels in spiny lobster at Shelter Island in October while tributyltin was higher in March. While sample sizes in this study were small, making it hard to be sure about temporal changes in contaminants, a concurrent study that included the same study locations revealed strong seasonal differences in suites of contaminants in Pacific oyster [19], and spiny lobster prey heavily upon bivalves (e.g., [64], Loflen, personal observation).…”

“…Further, 60% (18 of 30) of lobster tails tested contained concentrations of mercury that exceeded no-consumption thresholds with a strong positive relationship between mercury concentration and carapace size (i.e., age), indicating bioaccumulation [13]. This snapshot of mercury concentrations was valuable in setting recreational consumption guidelines for spiny lobster tails in San Diego Bay [14], but uncertainty remains about the risks associated with the consumption of whole lobster or viscera (vs. muscle only), loads of contaminants of emerging concern, including personal care products and pharmaceuticals [15,16], recently trending pesticides (e.g., neonicotinoids; [17]) and anthropogenic debris, including small natural and synthetic textile fibers and plasticizers (phthalates) (e.g., [18][19][20]). The impacts of small plastics on organisms are very well documented and include toxicity associated with compounds within and adhering to the plastics, as well as physical damage and interference with organismal functioning, including entanglement in digestive tracts and gills [21].…”

“…In addition, there remains much uncertainty about the additive or synergistic effects of multiple contaminants, even those that individually fall under dose or consumption limits [49][50][51]. Further, contaminant concentrations and therefore exposure risk can be variable in space, time and with species [19,[52][53][54][55]. This variability was seen with PBDEs in 2014-2015 when they were detected (and exceeded thresholds) in only 1 of 32 samples (2 whole lobster and 30 lobster tail samples) and in 2018-2019 when they were detected in each of the 2 crab samples but were at or below the detection limit in spiny lobster.…”

“…This study expanded on previous efforts to characterize shellfish contamination [13,19] and recreational harvest patterns [8] in San Diego Bay through the incorporation of additional species (crab), tissue types (viscera), contaminants (e.g., PFOS) and harvester types (shellfishers/hoop netters). The results indicate a need for the additional monitoring of contaminants, especially PAHs, which have been detected in Pacific oysters and sediments of San Diego Bay [19,67] but were not examined in this study, and emerging contaminants such as perfluoroalkyl substances (PFAS). Assessments are needed to characterize the shellfish harvest and consumption patterns of people who frequent CPFVs as these may differ from those observed on the public fishing piers (e.g., [8,68]).…”

“…For example, in this study organotin, pyrethroid and PFOS were only detected in spiny lobster, not the crabs, while DEET was detected in only the spider crab. Differences across broader taxonomic groups may be even greater given that taxonomy may be linked to differences in morphology and physiology (e.g., lipid content, rates of metabolism), lifestyle (e.g., hard vs. soft substrate dwelling), feeding or other functional groups any of which may influence contaminant exposure, uptake, metabolism and accumulation rates (e.g., [18,19,54,69]). This makes the use of commonly used fouling filter feeding shellfish (e.g., mussel, oyster) as indicators even less reliable for indicating potential risks associated with crabs in San Diego Bay, which are bottom-dwelling predators (and occasionally scavengers) [64,[70][71][72].…”