Book Description

The presence of contaminants of emerging concern (CECs) in the environment is a growing field of research for analytical environmental scientists. CECs are a class of anthropogenic pollutants not regulated by governmental agencies, and their potential deleterious environmental and human impacts are largely unknown. One of the main sources of CEC entry into the aquatic environment is wastewater treatment plant (WWTP) effluent as the treated water is often released into bodies of water, such as river and streams. Because most WWTPs were not designed to remove organic micropollutants, many CECs are poorly removed in traditional WWTPs and persist in the treated effluent waters. As a model system for study, the University Park WWTP treats the wastewater from the Penn State main campus. Following primary and secondary treatment, effluent water is then disinfected using sodium hypochlorite ("chlorine contact") and pumped for spray irrigation of over 500 acres of agricultural and forested lands called the Living Filter. The full characterization of CECs in environmental matrices requires the use of both targeted and non-targeted analysis employing a variety of advanced analytical techniques and multi-residue extraction methods. Comprehensive two-dimensional gas chromatography (GCxGC) coupled to time of flight mass spectrometry (TOFMS) is utilized for the separation and analysis of complex samples, such as wastewater. In these studies, GCxGC-TOFMS has been utilized for the non-targeted analysis of wastewater influent, effluent, and Living Filter irrigation water. Over the course of three years, these samples were investigated for CECs, revealing a new class of benzotriazole corrosion inhibitors and their transformation products. The tentatively identified chloromethyl-benzotriazole isomers were detected at higher concentrations in the effluent and irrigation water than the influent. Upon further investigation with a lab-scale synthesis, it was determined that the methyl-benzotriazoles in the influent react with sodium hypochlorite during chlorine disinfection to form previously unidentified chloromethyl-benzotriazoles. These compounds were not detected in the groundwater below the Living Filter. Traditionally, the extraction of wastewater and aqueous environmental samples is performed using liquid-liquid extraction (LLE). This method is time consuming and solvent intensive therefore a microextraction method, stir bar sorptive extraction (SBSE) was investigated. SBSE and LLE were compared for their application to multiclass organic contaminants in the University Park wastewater with GCxGC-TOFMS. LLE was found to be a better method for the quantitative analysis of a broader range of contaminants. SBSE was determined to be a more sensitive method for the non-targeted analysis of trace contaminants in effluent samples. These extraction methods were further tested and verified using wastewater from the Bellefonte, PA municipal WWTP as well as surface waters downstream of the WWTP outfall. 32 CECs, including a variety of pharmaceuticals and personal care products, were detected and tentatively identified in the samples. To further explore the fate and transport of CECs in the University Park wastewater, the soil and crops at the Living Filter were investigated. Specifically, corn roots, leaves, and grain were examined separately to determine the uptake and translocation of contaminants throughout the plant. The Living Filter samples were also compared to a corn crop control site at the agricultural research center at Rock Springs because it is not irrigated with the WWTP effluent. Target compounds detected in the soil and corn samples include herbicides, phthalates, and polycyclic aromatic hydrocarbons. Non-targeted principal component analysis of each sample type showed chemical differences between the control and Living Filter samples attributed to the treated wastewater irrigation. In addition, new chloro-dimethyl-benzotriazole compounds were tentatively identified in the wastewater as well as the Living Filter soil and corn root samples. Lastly, another class of CEC, microplastic particles (MPs), was investigated using a different set of analytical techniques. The surface characteristics and chemical composition of neat MP standards were compared to those extracted from personal care products and effluent water from the University Park WWTP. Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, and Optical Profilometry were all utilized for a more comprehensive view of the MP samples. This proof-of-concept study is the first to combine the three methods for MP analysis and demonstrate that MPs extracted from personal care products and WWTP effluent differ greatly from neat microsphere standards of similar sizes. The following research presented in chapters 2-6 has been published or submitted for publication in peer reviewed journals. Chapter 2 has been published in Science of the Total Environment and chapter 6 was published in Analytical Methods. Chapter 3 has been accepted for publication in Talanta. Chapter 4 has been submitted for publication in Analytical Methods and chapter 5 has been submitted to Chemosphere. I am first author on all five of these publications.