Occurrence of contaminants of emerging concern in mussels (Mytilus spp.) along the California coast and the influence of land use, stormwater discharge, and treated wastewater effluent Nathan G. Dodder1, Keith A. Maruya1, P. Lee Ferguson2, Richard Grace3, Susan Klosterhaus4,*, Mark J. La Guardia5, Gunnar G. Lauenstein6 and Juan Ramirez7 results suggest that certain compounds; for example, ABSTRACT alkylphenols, lomefloxacin, and PBDE, are appropriate Contaminants of emerging concern were measured for inclusion in future coastal bivalve monitoring efforts in mussels collected along the California coast in 2009- based on maximum concentrations >50 ng/g dry weight 2010. The seven classes were alkylphenols, pharmaceu- and detection frequencies >50%. Other compounds, for ticals and personal care products, polybrominated diphe- example PFC and hexabromocyclododecane (HBCD), nyl ethers (PBDE), other flame retardants, current use may also be suggested for inclusion due to their >25% pesticides, perfluorinated compounds (PFC), and single detection frequency and potential for biomagnification. walled carbon nanotubes. At least one contaminant was detected at 67 of the 68 stations (98%), and 67 of the 167 analytes had at least one detect (40%). Alkylphenol, INTRODUCTION PBDE, and PFC concentrations increased with urbaniza- The National Oceanic and Atmospheric tion and proximity to stormwater discharge; pesticides Administration’s National Status and Trends (NOAA had higher concentrations at agricultural stations. These NS&T) Mussel Watch Program measures the 1Southern California Coastal Water Research Project, Costa Mesa, CA 2Department of Civil & Environmental Engineering, Duke University, Department of Civil & Environmental Engineering, Durham, NC 3AXYS Analytical Services, Sidney, Canada 4San Francisco Estuary Institute, Richmond, CA 5Virginia Institute of Marine Science, College of William & Mary, Virginia Institute of Marine Science, Gloucester Point, VA 6National Oceanic and Atmospheric Administration, National Centers for Coastal Ocean Science, Silver Spring, MD 7TDI-BI/B&B Laboratories, College Station, TX 77845 *Currently at: Cradle to Cradle Products Innovation Institute, San Francisco, CA Land use, stormwater, and wastewater influence on CECs in mussels along the CA coast - 37 concentrations of coastal contaminants in bivalves (SWNT) are additives to a variety of materials and sediments to determine their spatial distribution (Schierz et al. 2012). Other flame retardants (OFR), and temporal trends, and to provide information to besides PBDE, include three sub-classes: alternatives assess the risk posed to marine wildlife and humans to PBDE flame retardants, hexabromocyclododecane through the use of coastal resources (Kimbrough (HBCD) isomers, and chlorinated organophosphate et al. 2008). Bivalves are mobility-limited filter flame retardants (Klosterhauset al. 2012). feeders which draw in water and particulates from The data analysis is structured to address the their surrounding environment and subsequently questions posed in the overall study design (Maruya bioaccumulate contaminants in their tissues. Their et al. In press a). First, the occurrence of individual tissue concentrations are indicators of local water CECs along the entire California coast is sum- contamination. In contrast to legacy contaminants marized. Second, the effect of station proximity to and trace metals which have been monitored by varying land cover, such as urban or agricultural, NS&T for more than 25 years (Kimbrough et al. on the contaminant concentrations is investigated. 2008), contaminants of emerging concern (CECs) are Third, the effect of station proximity to stormwater anthropogenic compounds which are released into and municipal wastewater discharge on the contami- the environment and may pose a risk, but at present nant concentrations is investigated. are largely unregulated and thus unmonitored within the Mussel Watch Program. Due to their potential risk, CECs have received attention from regulatory METHODS bodies. For example, the US EPA has produced A complete description of the study design action plans for several classes of CECs (http://www. is provided in Maruya et al. In press a. Briefly, epa.gov/oppt/existingchemicals/index.html) and the 68 mussel sampling stations were selected along California State Water Resources Control Board is the coast of California. Native mussels (Mytilus developing a process for monitoring for CECs in spp.) were collected from these stations between the coastal environment (Anderson et al. 2012). In November 2009 and April 2010. Land use within response, a multiagency California pilot study was 10 km was used to sort stations into four mutually initiated to begin to fill the CEC data gap and assess exclusive categories (urban, mixed development, the feasibility of incorporating CECs into the Mussel low development, and agricultural). Stormwater Watch Program. For this pilot study, details of the receiving stations were defined as within 1 km of study design and station selection are described in a permitted stormwater discharge region. Stations Maruya et al. In press a, the spatial distribution of receiving POTW discharge were within 2 km of legacy contaminants are described in Edwards et al. small (<100 MGD) or 5 km of large (>100 MGD) In press, and incorporation of passive samplers as outfalls. Stations could have one of four categories mussel tissue surrogates are provided in Alvarez et (stormwater only, stormwater and POTW, POTW al. In press; a synthesis of each of these components only, or no discharge). can be found in Maruya et al. In press b. A total of 166 contaminants plus SWNTs were Analyte selection was based primarily on two cri- analyzed in the mussel tissue. Some contaminant teria. First, the compound was known or suspected classes were measured at a subset of the 68 sampling to bioaccumulate from previous surveys in California stations. The individual analytes are listed in the or other regions. Second, robust analytical methods Supplemental Information (SI) Table SI-1 (ftp:// capable of processing the relatively large sample ftp.sccwrp.org/pub/download/DOCUMENTS/ set were available. The seven CEC classes were as AnnualReports/2013AnnualReport/ar13_037_047SI. follows. Alkylphenols (AP) are nonionic surfactants pdf) and were measured by positive or negative (David et al. 2009); polybrominated diphenyl ethers mode electrospray ionization (+/-ESI) liquid (PBDE) are flame retardants (Shawet al. 2009); chromatography tandem mass spectrometry (LC/ perfluorinated compounds (PFC) are polymers used MS/MS), or electron impact (EI) or electron capture in a variety of products (Houde et al. 2006); pharma- negative chemical ionization (ECNI) mode gas ceuticals and personal care products (PPCP) include chromatography mass spectrometry (GC/MS). APs antibiotics, antidepressants, and stimulants; current and PPCPs were measured by +/-ESI LC/MS/MS use pesticides (CUP) include insecticides, fungicides, (a modified version of EPA Method 1694), PFCs by and herbicides, and single walled carbon nanotubes -ESI LC/MS/MS (Kannan et al. 2001), CUPs by EI Land use, stormwater, and wastewater influence on CECs in mussels along the CA coast - 38 GC/MS (a modified version of EPA Method 1699), Statistical Analysis PBDEs by ECNI GC/MS, and OFRs by EI/ECNI Plotted tissue concentrations (dry weight) were GC/MS and -ESI LC/MS/MS (La Guardia et al. transformed as log10(x+1), where x is the concentra- 2012). SWNTs were measured by both near infrared tion. The tick marks on the y-axes of the box and fluorescence spectroscopy (NIRF; Schierzet al. whisker plots were adjusted for this transformation. 2012) and inductively-coupled plasma mass spec- Non-parametric Kruskal-Wallis tests followed by trometry (ICP-MS). Descriptions of each extraction pairwise Wilcoxon tests were used to compare tissue and instrumental method are provided in the SI. concentrations among the different land use and discharge categories. The statistical analysis was performed using R (R Core Team 2012). Quality Control Analytical precision and accuracy were evaluated using a performance based approach beginning RESULTS AND DISCUSSION with a comprehensive set of data quality objectives CECs as a group were detected at 67 of 68 (DQO; Maruya et al. In press a). The performance of stations (98%); the exception was station SSSS\ each analytical method was compared against initial San Simeon Point-San Simeon Point, located in project-wide thresholds, and then the DQOs were an undeveloped region of the central coast that is adjusted to account for actual method performance approximately equidistant (350 km) between the Los Angeles and San Francisco Bay metropolitan areas. (Tables SI-2 and SI-3). The adjustment required Figure 1 shows the total concentration at each station satisfactory matrix spike/matrix spike duplicate (MS/ for each compound class. The order by mean con- MSD) recovery for all accepted data. MS/MSD per- centration was PPCP > AP > PBDE > CUP > OFR formance directly tests the accuracy of the method, > PFC. The variation in concentration within each and was therefore considered more important than class spanned between approximately 1 and >3 orders the recovery of the surrogate standards. Threshold of magnitude. Table 1 summarizes the occurrence of adjustments were reviewed by the laboratories to individual CECs across all stations. The total number ensure they conformed to known past performance. of stations analyzed per compound varied because