An Adaptive, Comprehensive Monitoring Strategy for Chemicals of Emerging Concern (CECs) in California's Aquatic Ecosystems

Abstract

A scientific advisory panel was convened by the State of California to recommend monitoring for chemicals of emerging concern (CECs) in aquatic systems that receive discharge of municipal wastewater treatment plant (WWTP) effluent and stormwater runoff. The panel developed a risk-based screening framework that considered environmental sources and fate of CECs observed in receiving waters across the State. Using existing occurrence and risk threshold data in water, sediment, and biological tissue, the panel applied the framework to identify a priority list of CECs for initial monitoring in three representative receiving water scenarios. The initial screening list of 16 CECs identified by the panel included consumer and commercial chemicals, flame retardants, pesticides, pharmaceuticals and personal care products, and natural hormones. The panel designed an iterative, phased strategy with interpretive guidelines that direct and update management actions commensurate with potential risk identified using the risk-based framework and monitoring data. Because of the ever-changing nature of chemical use, technology, and management practices, the panel offered recommendations to improve CEC monitoring, including development of bioanalytical screening methods whose responses integrate exposure to complex mixtures and that can be linked to higher-order effects; development or refinement of models that predict the input, fate, and effects of future chemicals; and filling of key data gaps on CEC occurrence and toxicity. Finally, the panel stressed the need for adaptive management, allowing for future review of, and if warranted, modifications to the strategy to incorporate the latest science available to the water resources community.

The occurrence and fate of chemicals of emerging concern in coastal urban rivers receiving discharge of treated municipal wastewater effluent

“… where C max is the maximum measured environmental concentration, PNEC is the predicted no‐effect concentration, and uncertainty factors range from 10 to 1000. Values of MTQs that exceeded a set threshold (unity) were used to identify CECs to include in investigative monitoring for different classes of receiving waters, including effluent‐dominated waterways similar to those studied in the present study .…”

Antibiotics as CECs: An Overview of the Hazards Posed by Antibiotics and Antibiotic Resistance

“…Similarly only one antibiotic-Tetracycline, and one antibacterial agent-Triclosan, had high MEC/NOEC ratios (0.108-0.15), low margins of safety (6.70-9.26) and high MIC ratios (1600-320,000) when compared to the other nine antibiotics and one antibacterial agent. Maruya et al (2013) applied the use of Uncertainty Factors to address the quality (inadequacies/incompleteness) of toxicological, chemistry and microbial data in estimating the hazards of CECs for the State of California (Anderson et al, 2012). For antibiotic resistance, Uncertainty Factors (10-100) were used when data for specific indicator species were lacking (e.g., E. coli) and/or for a lack of MIC values for both sensitive and resistant bacteria were not available.…”

Occurrence of PPCPs in the marine environment: a review

“…Questions regarding the occurrence (frequency of detection and concentration) and its variability were raised and factors such as land use, proximity of wastewater treatment plant outflow, and stormwater runoff were discussed. To answer these questions, native mussels were collected and analyzed at 68 sampling sites along the California coasts to characterize the spatial extent and temporal trends in contaminant concentrations (Bricker et al 2014;Dodder et al 2014;Maruya et al 2014aMaruya et al , 2014b. The results showed the detection of 30 out of 88 PPCPs with the frequencies of detection of lomefloxacine and sertraline exceeding 60 %.…”