Factors Affecting Risk Perceptions about the Human Health Effects Resulting from Harmful Algal Bloom Exposure.

In the Great Lakes region, harmful algal blooms (HABs) are known cyanobacterial blooms that pose significant public health, environmental, and socio-economic risks. Risk information related to HABs is primarily communicated through state and local government agencies; however, the effectiveness of these communication strategies and how local stakeholders are learning about such risks remains unclear. The objective of this study is to examine how to effectively communicate HABs risks and understand public risk perceptions of HABs-related risks during recreational lake use in Michigan. Guided by the social amplification of risk framework, this qualitative study conducted fieldwork in 2021, including 27 semi-structured interviews with individuals from vulnerable populations. Interviews explored participants' awareness, experiences, and communication preferences related to HABs. Results showed that while respondents were familiar with general algal ecology, they lacked knowledge about HABs-related health effects. Vulnerable populations reported greater trust in local networks, community leaders, and peers than in state or federal agencies, revealing a gap between trusted information sources and where official information is provided. Findings indicate that effective HAB communication must combine not only accurate scientific information but also include communication approaches that build trust, account for social context and audience characteristics, and actively involve communities in engaging with risk information.