Plastics in sediments and fishes at the mouth of Chollas Creek, San Diego, USA
|Author(s)||Talley Theresa1, Venuti Nina2, Whelan Rachel3|
|Affiliation(s)||1 : California Sea Grant, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California, USA
2 : Ecology Graduate Group, University of California Davis, One Shields Ave., Davis, California, USA
3 : Ocean Discovery Institute, 4255 Thorn St., San Diego, California, USA
|Keyword(s)||killifish, sailfin molly, plastics, contaminants, microplastics, pthalates, natural history, trash, debris, diet|
The extent to which small plastics and potentially associated compounds are entering coastal food webs, especially in estuarine systems, is only beginning to be realized. This study examined an estuarine reach at the mouth of urbanized Chollas Creek in San Diego, California to determine: 1) the extent and magnitude of microplastics pollution in estuarine sediments and fish, 2) the extent and magnitude of SVOC contamination in estuarine fish, and 3) whether fish preferentially ingested certain types of microplastics, when compared with the microplastic composition of creekbed sediments. Surface sediments (0-5 cm depth) contained about 10,000 small plastic pieces per m2, consisting mostly (90%) of fibers, and hard and soft pieces. Nearly 25% of fish contained small plastics, but prevalence varied with size and between species. Of the 25 types of small plastics found in sediment, fish preferred about 10 types (distinct colors and forms). Several SVOCs, both water soluble and sediment-associated compounds, were found in the two species of fish tested. This study revealed that a species’ natural history may influence contamination levels, and warrants further study to better understand the pathways of plastics and associated contaminants into and throughout coastal food webs, and the potential health risks for small and/or low-trophic level organisms.
|Acknowledgments||Theresa S Talley, California Sea Grant, University of California San Diego|
In June 2015, sediments and fish were sampled along a 250-m long reach of tidal brackish Chollas Creek in San Diego, California USA, located about 1.5 km upstream of the mouth of the creek by San Diego Bay (Latitude: 32.6953° N, Longitude:-117.1230° W). Estuarine sediments were collected at low tide throughout the reach of creek, in nine 10-cm diameter x 5-cm depth cores (393 cu cm). Common wetland fish were trapped using metal minnow traps baited with cat food placed in nylon sleeves. Three species were captured: California killifish (Fundulus parvipinnis; n = 68), longjaw mudsucker (Gillichthys mirabilis; n = 4), and sailfin molly (Poecilia latipinna; n = 82). In the field, all fish collected for gut analysis were placed in zip-top bags (one bag per trap). Additionally, two composite samples (7 California killifish and 8 sailfin molly) were collected and immediately placed into clean glass jars for analysis of SVOCs (pthalates).