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This study examined the concentrations and compositions of polycyclic aromatic hydrocarbon (PAH) contaminants in the surficial sediments of the Saint John Harbour (SJH) and assessed PAH exposure to local aquatic biota. Our findings suggest that sedimentary PAH contamination is heterogeneous and widespread in the SJH, with several sites exceeding the Canadian and NOAA recommended guidelines for the protection of aquatic life. Despite high concentrations of PAHs at some sites, there was no indication that local nekton was affected. Lack of a biological response may be due in part to a low bioavailability of sedimentary PAHs, presence of confounding factors (e.g., trace metals), and/or adaptation of local wildlife to the historic PAH contamination in this region. Overall, although no indication of effects to wildlife was observed with the data collected in the present study, continued efforts should be made to remediate highly contaminated areas and reduce the prevalence of these compounds. • Mean total sediment PAH concentration exceeded CCME ISQGs in 6/13 sampled sites. • There was no significant change in overall sediment PAH concentration (2018–2022). • There is no immediate threat of sediment PAH contamination to sampled nekton. • There may be limited bioavailability of PAHs, decreasing their exposure to biota. [ABSTRACT FROM AUTHOR]

Adaptation to drought is particularly challenging on remote island atolls, such as those found in the Republic of the Marshall Islands (RMI), a nation of 58,000 populating 29 low-lying coral atolls spread over >2 million km2. Exposure to consecutive atmospheric hazards, such as meteorological floods and droughts diminish scarce water resources and erode the resilience of island communities. Drought impact mitigation measures must supply emergency drinking water to stricken communities, while simultaneously conserving natural sources in order to reduce their vulnerability to subsequent events. Household surveys (n = 298) and focus group discussions (n = 16) in eight RMI communities revealed that 86% of households have experienced drought and 88% reported using multiple water sources to meet normal household needs. With no surface water and a thin freshwater lens (FWL), rainwater collected from rooftops is the most common household water source. The traditional use of carved hollows in the base of coconut trees to collect rainwater ("Mammaks") appears to have been displaced by large rainwater tanks. However, rationing of rainwater for consumption only during drought was widely reported, with private wells supporting non-consumptive uses. Reverse osmosis (RO) desalination units have provided relief during drought emergencies but concerns have been raised around dependency, maintenance challenges, and loss of traditional water practices. Most notably, RO use has the potential to change the anthroposhpere by adversely affecting the FWL; 86% of RO units were installed at island-centre where excessive pumping can cause upconing, making the FWL brackish. Balancing the introduction of desalination technology to mitigate water shortages with maintenance of traditional water conservation practices to preserve the quantity and quality of the FWL is a promising strategy on island atolls that requires further investigation. Unlabelled Image • Small island states are among the most vulnerable to drought and climate change. • Cycling of multiple household water sources increases resilience to drought. • Austere usage behaviors conserve rainwater for drinking during drought. • Emergency water created using reverse osmosis presents a hazard to groundwater. [ABSTRACT FROM AUTHOR]