https://www.um.edu.mt/library/oar/handle/123456789/314 2026-04-16T10:12:55Z 2026-04-16T10:12:55Z Scerri, Mark M. Haas, Kristin Gauci, Adam Schiedek, Thomas https://www.um.edu.mt/library/oar/handle/123456789/145170 2026-03-26T13:54:49Z 2026-01-01T00:00:00Z

Title: Atmospheric deposition of polycyclic aromatic hydrocarbons in southwestern German soils : sources, cancer risks and policy implications Authors: Scerri, Mark M.; Haas, Kristin; Gauci, Adam; Schiedek, Thomas Abstract: Background: Polycyclic aromatic hydrocarbons (PAHs) comprise a group of persistent carcinogenic pollutants whose transfer from air to soil via the atmospheric deposition represents a major chronic exposure pathway. Regulatory frameworks across Europe and beyond rely heavily on single compound indicators such as benzo[a]pyrene and focus predominantly on point source contamination, creating potential blind spots for contamination by deposition. This observational study quantified concentrations, identified emission sources and assessed the lifetime cancer risk of 20 PAHs in 97 topsoil samples from four locations in southwestern Germany. Results: The total concentrations of the 16 USEPA priority pollutants ranged from 52 to 3956 μg/kg, with median values between 214 μg/kg (Hunsrück) and 371 μg/kg (Saarland/Palatinate Forest). Most sites (76%) were classified as “not” or “weakly” contaminated, while 12% were “heavily contaminated”. PMF identified four major sources accounting for 97% of the total PAH mass: coal/coke combustion (34.5%), biomass combustion (9.8%), petrogenic sources (15.8%) and combustion of liquid fuels from vehicles and stationary sources (37.0%). A Monte Carlo based cancer risk assessment for ingestion, dermal contact, and inhalation indicated cumulative risks between 10-4 – 10-6, with ingestion and dermal contact as the dominant pathways. Localized hotspots with elevated risks were identified, indicating the need for site specific follow up. Conclusions: Liquid fuel combustion represents the dominant process influencing soil contamination by atmospherically deposited polycyclic aromatic hydrocarbons (PAHs) in the study area. While measured concentrations at most sites remain within current regulatory limits, the cumulative toxicity of PAH mixtures results in cancer risks that are not negligible. These findings point to a structural limitation in existing EU and national soil protection frameworks (e.g., the German BBodSchG/BBodSchV), which remain primarily oriented toward contamination from identifiable point sources and do not adequately account for diffuse deposition-driven inputs. Consequently, soils affected by atmospheric PAH deposition may fall outside current regulatory attention despite carrying a cumulative toxic burden of potential relevance for human health. Strengthening soil quality assessment approaches to incorporate cumulative toxicity metrics and deposition-driven contamination pathways would improve health protection and better align soil policy with contemporary emission patterns.

2026-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/144933 2026-03-16T14:12:33Z 2026-01-01T00:00:00Z

Title: Interactions between wild fauna and farmed tuna in Maltese coastal waters Abstract: Atlantic bluefin tuna (Thunnus thynnus) ranching is a major aquaculture activity in Malta, yet interactions between tuna farms and wild fauna remain poorly documented. This study addresses this gap by identifying which wild fauna aggregate around farm sites, the drivers of these aggregations, and the resulting ecological and operational implications. Nineteen semi-structured interviews were conducted with tuna farm personnel and environmental monitors across four ranching sites, providing multi-year observations on species presence, behavior, and interaction patterns. In total, 41 wild fauna species and 143 observations were recorded. Aggregation was primarily driven by uneaten baitfish, habitat provisioning from cage structures, and proximity to migratory routes. Findings indicate that tuna farms act as fish aggregating devices (FADs) that alter local trophic dynamics. Consumption of uneaten baitfish can reduce organic loading and improve the condition of aggregated fauna, offering localized ecological benefits. However, reliance on baitfish also perpetuates pressure on wild forage fish stocks, and predictable food subsidies may create ecological traps, behavioral dependency, and changes to natural movement patterns. This study provides the first baseline assessment of these interactions in Malta and highlights the need for long-term monitoring and adaptive management to balance aquaculture productivity with ecosystem sustainability. Description: MSc. (EMS)(Melit.)

2026-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/144858 2026-03-12T13:36:28Z 2026-01-01T00:00:00Z

Title: Sustaining snow : historical trends and future climate impacts on snowmaking sustainability in Southeastern U.S. ski resorts Abstract: Snowmaking has become an essential adaptation for ski resorts in the Southeast United States, where marginal winter temperatures and low natural snowfall increasingly constrain reliable operations. This study evaluates the feasibility and sustainability of snowmaking under historical and projected climate conditions across six representative ski resorts: Wisp, Snowshoe, Winterplace, Massanutten/Wintergreen, and Bryce, using NOAA hourly weather records from 2005 to 2025. The analysis used Linear regression scenario modeling to estimate 2040 snowmaking conditions under moderate and high warming scenarios. Results show available snowmaking hours reducing by 0.31-5.11% per decade, with February exhibiting the most substantial increase in both mean and cold hour wet-bulb temperatures (≤28°F/-2.2°C) of the winter months (Feb-Mar). Precipitation totals and extremes show no clear trends but remain operationally disruptive due to frequent and episodic heavy rain events. Scenario modeling suggests slight increases in Wet-bulb temperatures and proportional declines in cold hours by 2040. Interviews with snowmaking managers at Wisp, Snowshoe, and Massanutten confirm that resorts are already experiencing later openings, shorter cold spells, and growing reliance on high-capacity, automated snowmaking systems. These findings indicate that even modest warming can disproportionately affect snowmaking efficiency, resource demand, and operational stability in this ski region. The study concludes that long-term viability will depend on strategic investment in snowmaking technology, expanded water and energy infrastructure, and critical integration of on-site monitoring through summit and base weather stations. Description: MSc. (EMS)(Melit.)

2026-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/144857 2026-03-12T13:30:49Z 2026-01-01T00:00:00Z

Title: Land as community : an assessment of habitat fragmentation, development pressure, and wildlife impact along the southern border of Shenandoah National Park Abstract: The fragmentation of large, protected areas is a growing concern in ecology, as increased urban and infrastructural development isolates habitat patches and can lead to increased human-wildlife conflict, especially along roadways. Research has shown that fragmentation and loss of forest cover in protected areas is correlated with increased infrastructural development, and that roadways have an outsized effect on surrounding habitat and animal populations for their size, though there are gaps in this knowledge relevant to specific protected areas and highly mobile animal species. I examined the area around the Interstate 64 corridor that sits between the southern tip of Shenandoah National Park and the Blue Ridge Parkway, utilizing land cover, topographic, and deer-vehicle crash data to analyze the effect of infrastructure and urban development on the fragmentation of white-tail deer habitat. Habitat fragmentation was shown to be more widespread south of the highway corridor, where there is less protected land area, allowing for more dense infrastructural development along the mountain ridges that comprise the bulk of the study area. Additionally, I-64 was shown to be the greatest barrier to deer within the study area due to its width and much higher traffic volume than surrounding county and state roads. Food and water resources are scarce within the study area, likely leading to increased competition in the autumn months, incentivizing animals to range further in search of nutritional requirements – making the highway crossing a necessity to move between both protected areas. Fragmentation analysis highlights the importance of holistic management of protected areas, treating them as part of wider ecosystems rather than closed systems, as well as providing insights for the creation of wildlife corridor implementation, which would help reduce human-wildlife conflict within the study area. Description: MSc. (EMS)(Melit.)

2026-01-01T00:00:00Z