From March to June 2020, governments across the world imposed lockdowns in an attempt to reduce the transmission of COVID-19 during the early phase of the pandemic. This period of time in which human activity slowed worldwide has been coined the "Anthropause". The goal of this study was to determine if sunscreen pollution abated during the Anthropause and to identify the severity of the pollution when tourism/recreation recovered at two coastal units of the U.S. National Park System: Kaloko-Honokōhau National Historical Park in Hawaiʻi, U.S.A. and Cape Lookout National Seashore in North Carolina, U.S.A. Active ingredients of sunscreen products were measured in water and sand samples at both locations, including oxybenzone, octinoxate, octocrylene, octisalate, homosalate, and relevant breakdown products of some of these ingredients. A risk assessment was conducted on Anthropause and post-Anthropause contaminant levels for both locations to determine if there was a threat reduction during the Anthropause, and whether tourism recovery in the post-Anthropause period served as a threat to coastal wildlife. Both national park units exhibited an almost absolute reduction in the levels of sunscreen contamination during the Anthropause period, a striking commonality considering the geographic expanse separating the parks. Once travel restrictions were lifted, a large influx of tourists ensued at both locations, resulting in a relatively sudden and dangerous increase in the levels of sunscreen chemical pollution. This study supports the argument that unmanaged tourism is a source of coastal sunscreen pollution that poses a threat to the localized continuity of species populations and biodiversity, especially to coral reefs and fisheries.

Sunscreen pollution is abated during the COVID-19 “Anthropause” of 2020 in two U.S. National Parks: Cape Lookout National Seashore and Kaloko-Honokōhau National Historical Park