Phthalates are ubiquitous in the built environment and are used across various fields, despite known endocrine disruptive properties, and other associated health hazards, including abnormalities in reproductive health and development. I investigated the presence of phthalates in the built environment using the Health Product Declaration (HPD) repository to survey for products containing these chemicals, investigated the literature for possible health effects and alternatives to phthalates, and conducted a laboratoy-based feasibility study of urinary biomarkers associated with phthalates using wastewater-based epidemiology (WBE) on a US university campus at the building-scale. Of the 5,278 products in the HPD repository, 73 contained phthalates and were most commonly found in windows, doors, flooring, sealants, insulations, and furnishings. Alternative plasticizers (cardanol, epoxidized soybean oil, hydrogenated castor oil) usage were identified in 10 products from HPD repository. The two wastewater samples analyzed by liquid chromatography-tandem mass spectrometry (LC-MS-MS) showed that dimethyl phthalate (DMP) was detectable, as well as its human metabolite, monomethyl phthalate (MMP), observed at a concentration of 163-202 ng/L. These results indicate low human exposure from the building materials in the limited convenience sample investigated. Future studies of building scale wastewater-based epidemiology are recommended to investigate these and other phthalates commonly found in the built environment, including diisononyl phthalate (DINP) and diisononyl hexahydrophthalate (DINCH).
In LAC, residential electricity demand could increase as much as 55-68% between 2020 and 2060, and building technology lock-in has constricted the options for mitigating energy demand, as major changes to the building stock itself are not possible, as only a small portion of the stock is turned over every year. Aggressive and timely efficiency upgrades to residential appliances and building thermal shells can significantly offset the projected increases, potentially avoiding installation of new generation capacity, but regulations on new construction will likely be ineffectual due to the long residence time of the stock (60+ years and increasing). These findings can be extrapolated to other U.S. cities where the majority of urban expansion has already occurred, such as the older cities on the eastern coast. U.S. population is projected to increase 40% by 2060, with growth occurring in the warmer southern and western regions. In these growing cities, improving new construction buildings can help offset electricity demand increases before the city reaches the lock-in phase.
Environmental releases of neonicotinoid and fipronil insecticides via U.S. wastewater infrastructure
A literature review demonstrated that municipal sewage sludge produced by wastewater treatment plants around the world contains detectable quantities of microplastics. Application of sewage sludge on land was shown to represent a mechanism for transfer of microplastics from wastewater into terrestrial environments, with some countries reporting as high as 113 ± 57 microplastic particles per gram of dry sludge.
To address the notable shortcoming of inconsistent reporting practices for microplastic pollution, this thesis introduced a novel, online calculator that converts the number of plastic particles into the unambiguous metric of mass, thereby making global studies on microplastic pollution directly comparable.
This thesis concludes with an investigation of a previously unexplored and more personal source of plastic pollution, namely the disposal of single-use contact lenses and an assessment of the magnitude of this emerging source of environmental pollution. Using an online survey aimed at quantifying trends with the disposal of lenses in the US, it was discovered that 20 ± 0.8% of contact lens wearers flushed their used lenses down the drain, amounting to 44,000 ± 1,700 kg y-1 of lens dry mass discharged into US wastewater.
From the results it is concluded that conventional and medical microplastics represent a significant global source of pollution and a long-term threat to ecosystems around the world. Recommendations are provided on how to limit the entry of medical microplastics into the built water environment to limit damage to ecosystems worldwide.