MONITORING EMERGING CONTAMINANTS IN WASTEWATER IMPACTED VERNAL POOLS USING INTEGRATIVE AND GRAB SAMPLING

Open Access
- Author:
- Hayden, Kathryn
- Graduate Program:
- Agricultural and Biological Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- June 12, 2019
- Committee Members:
- Heather E. Gall, Thesis Advisor/Co-Advisor
Herschel Adams Elliott, Committee Member
John Earl Watson, Committee Member - Keywords:
- POCIS
vernal pools
integrative sampling
grab sampling
emerging contaminants - Abstract:
- Many of the active ingredients in pharmaceuticals and personal care products (PPCPs) can persist through wastewater treatment plants and be released into the environment. With recent advancements in analytical techniques, PPCPs are increasingly detected in wastewater effluent. However, PPCPs remain largely unregulated in the environment due to a lack of monitoring data and understanding of the toxicological impacts they pose to ecological and human health. While research has focused on the presence of PPCPs in lotic waters (rivers and streams), this study aims to evaluate the temporal variability of PPCPs in lentic waters (specifically vernal pools) impacted by treated wastewater, using integrative and grab (point-in-time) sampling techniques. In this study, the use of Polar Organic Chemical Integrative Sampler (POCIS) membranes was compared to grab sampling techniques to monitor the presence and persistence of 39 selected PPCPs in 3 vernal pools receiving treated wastewater (study sites) from spring through fall 2018 and 3 non-irrigated control sites. The three irrigated sites were located at the Pennsylvania State University’s “Living Filter”, where treated wastewater from the University’s wastewater treatment plant is spray irrigated onto cropped and forested land. The control sites were vernal pools located in Scotia Barrens (State Gamelands 176). The overarching goal was to evaluate the effectiveness of integrative sampling and grab sampling techniques in monitoring the occurrence and persistence of PPCPs in wastewater-impacted vernal pools. Overall, out of the 39 PPCPs studied, five (dextromethorphan, carbadox, tylosin, triclocarban, and triclosan) was not detected in any grab or POCIS samples. This study addressed three objectives. Objective 1 considers how frequently PPCPs were detected in grab sampling vs. integrative sampling over the study period across all six vernal pools. In general, more PPCPs are detected in POCIS than in grab water samples. However, both sampling techniques (integrative and grab) were needed to evaluate the presence and persistence of PPCPs in vernal pools over time. Objective 2 compares the presence and concentration of PPCPs in the three study site vernal pools and in the laterals that feed them. POCIS and grab samples collected from laterals and vernal pools were used to detect the presence of PPCPs. Overall, POCIS detected more compounds compared to lateral and vernal pool grab water samples. Additionally, study site 1 proves to be the most sensitive to effluent inputs. Part 2 of objective 2 compares PPCP concentrations from grab water samples at the three study sites. Grab water samples collected from vernal pools are compared to grab water samples collected from their contributing laterals. Generally, concentrations were recorded at higher levels in laterals. Aside from the pesticide and hormone studied, over-the-counter medicines are detected more frequently than other categories of emerging contaminants studied in lateral and vernal pool grab water samples. Objective 3 compares the concentrations of over-the-counter medicines found in vernal pool grab water samples to physical and chemical system characteristics of the three study site vernal pools. Three parameters are evaluated: water level, water temperature, and dissolved oxygen. Unfortunately, the three parameters are insufficient in explaining the variability among concentrations over time across the study site pools. Therefore, it is likely that other factors, such as clay or organic matter content, could explain more variability. For example, PPCPs could be sorbed/desorbed from organic matter under anerobic conditions. As a result, PPCPs may not be accurately captured by point-in-time grab sampling. Without integrative sampling, PPCPs that may be slowly released into the vernal pool over time under anerobic conditions may not be captured. However, both grab sampling and integrative sampling techniques are needed to capture the holistic presence and persistence of PPCPs in vernal pools over time. Knowing the diffusive mass transfer and membrane uptake rates of the POCIS system, and the hydrodynamic conditions of the vernal pools, the analyte concentrations on the sorbent can be used to estimate time-weighted average concentrations for the system being studied. These time-weighted concentrations can then allow for an assessment of the toxicological impacts of PPCPs on aquatic organisms, especially amphibians. In this way, future studies may be able to better inform researchers and policymakers on how PPCPs should be monitored in lentic systems and how vernal pools are evaluated as critical habitats for amphibians.