The objective of this research is to evaluate the influence of the factors identified by the Johnson, Kendall and Robert’s theory that affect the strength of the detachment force necessary to remove a particle of contaminant from a surface, and the roughness of the surface in which the contaminant is present, on predicting the efficiency of removal of loose contamination. Two methods were used to reach this objective: the first method consisted of quantifying the contamination by weight and the second method of quantifying the contamination by counting alpha and gamma particles. As a result, it was determined that for particles of 5 μm, the interaction between contaminant-wipe and contaminant-surface were significant. However, for particles between 37-149 μm, the contaminant-surface interaction was the only significant interaction affecting the amount of contamination removed. The results obtained were already used at a contaminated site, confirming the prediction of contamination removed

Phthalate esters (PEs) and alternative plasticizers used as additives in numerous consumer products are continuously released into the environment leading to subsequent human exposure. The ubiquitous presence and potential adverse health effects (e.g. endocrine disruption and reproductive toxicity) of some PEs are responsible for their bans or restrictions. This has led to increasing use of alternative plasticizers, especially cyclohexane-1,2-dicarboxylic acid diisononyl ester (DINCH). Human exposure data on alternative plasticizers are lacking and clear evidence for human exposure has previously only been found for di(2-ethylhexyl) terephthalate (DEHTP) and DINCH, with increasing trends in body burdens. In this thesis, a study population of 61 adults (age: 20–66; gender: 16 males and 45 females) living in the Oslo area (Norway) was studied for their exposure to plasticizers. Information on sociodemographic and lifestyle characteristics that potentially affect the concentrations of PE and DINCH metabolites in adults was collected by questionnaires. Using the human biomonitoring approach, we evaluated the internal exposure to PEs and DINCH by measuring concentrations of their metabolites in urine (where metabolism and excretion are well understood) and using these data to back-calculate daily intakes. Metabolite levels in finger nails were also determined. Since reference standards of human metabolites for other important alternative plasticizers apart from DINCH (e.g. DEHTP, di(2-propylheptyl) phthalate (DPHP), di(2-ethylhexyl) adipate (DEHA) and acetyl tributyl citrate (ATBC)) are not commercially available, we further investigated the urine and finger nail samples by Q Exactive Orbitrap LC-MS to identify specific metabolites, which can be used as appropriate biomarkers of human exposure. Many metabolites of alternative plasticizers that were present in in vitro extracts were further identified in vivo in urine and finger nail samples. Hence, we concluded that in vitro assays can reliably mimic the in vivo processes. Also, finger nails may be a useful non-invasive matrix for human biomonitoring of specific organic contaminants, but further validation is needed. Concentrations of PEs and DINCH were also measured in duplicate diet, air, dust and hand wipes. External exposure, estimated based on dietary intake, air inhalation, dust ingestion and dermal uptake, was higher or equal to the back-calculated internal intake. By comparing these, we were able to explain the relative importance of different exposure pathways for the Norwegian study population. Dietary intake was the predominant exposure route for all analyzed substances. Inhalation was important only for lower molecular weight PEs, while dust ingestion was important for higher molecular weight PEs and DINCH. Dermal uptake based on hand wipes was much lower than the total dermal uptake calculated via air, dust and personal care products, but still several research gaps remain for this exposure pathway. Based on calculated intakes, the exposure risk for the Norwegian participants to the PEs and DINCH did not exceed the established tolerable daily intake and reference doses, and the cumulative risk assessment for combined exposure to plasticizers with similar toxic endpoints indicated no health concerns for the selected population. Nevertheless, exposure to alternative plasticizers, such as DPHP and DINCH, is expected to increase in the future and continuous monitoring is required. Findings through uni- and multivariate analysis suggested that age, smoking, use of personal care products and many other everyday habits, such as washing hands or eating food from plastic packages are possible contributors to plasticizer exposure. / <p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Manuscript.</p>

<p dir="ltr">Healthcare-acquired infections (HAIs) cause a burden in acute care hospitals in the United States. HAIs are caused by <i>Staphylococcus aureus</i>, along with other pathogens found on high-touch and non-high-touch surfaces in hospital environments (e.g., bed rails, blood pressure cuffs, countertops, and floors). To minimize the growth and cross-contamination of pathogens, it is vital to use disinfectants for surface decontamination. In this work, the impact of different application methods and disinfectant active agents was evaluated for use on different healthcare-related surfaces. The first study examined the cross-contamination potential of an auto-scrubber when used to clean and disinfect a 2m² vinyl floor contaminated with <i>S. aureus</i>. Five EPA-registered disinfectants and a cleaner were used with three application methods. Hydrogen peroxide and quaternary ammonium compounds-based disinfectants significantly resulted in less cross-contamination compared to the cleaner. However, there were no significant differences among the application methods used. In the second study, manual floor cleaning and disinfecting on a two-square-meter vinyl floor with three different moping materials were evaluated to assess their ability to prevent cross-contamination. Evidence showed that there were significant differences among the products used, with Hydrogen peroxide and quaternary ammonium compound products being the most effective. The cleaner caused the most cross-contamination, while cotton mops resulted in significant cross-contamination among materials used. Study three investigated the differences among four application methods used with three different wiping cloths (Cotton, microfiber, and nonwoven) on a 2m² Formica board. A spray surface and wipe method was successful in decreasing <i>S. aureus</i> on the surface. A hydrogen peroxide-based product was most effective in reducing bacteria at contamination areas and minimizing cross-contamination. Microfiber cloth picked up significantly more bacteria at contaminated areas. Post disinfection, there was evidence of cross-contamination at sampling areas regardless of product type, wiping cloth, and application methods used, with the cotton cloth causing the most cross-contamination. Viable bacteria were found on the wiping cloths used and on worker's gloves. Together, this work shows that the use of disinfectants is important in hospital environments. The choice of product, wiping material, and application method are principal in the disinfection process as they influence disinfection failure or success.</p>