Among the determinants of environmental health risk perception, health literacy and social media messages have been generally neglected. This study details the environmental health risk perception and its determinants in Italian university students, including a measure of functional health literacy and an analysis of newspapers and social media. A cross sectional survey was carried out among students from 15 Italian universities and different disciplines (grouped into Scientific-Health and Humanistic-Legal-Social sectors) using a self-administered anonymous questionnaire, divided into six sections: socio-demographic characteristics, information on health and environment, environmental health risk perception, trust, attitudes and behaviors and functional health literacy. Local newspapers and tweets in the same areas and period were analyzed in relation to quantity and topics. The study population included 4778 students (65.1% female) aged 21 ± 4.3 years, and functional health literacy was low (below the cutoff value) for 44.4% of students. A new outcome of the survey is that the detected association between high functional health literacy a higher global health risk perception and trust in institutions both as sources of information and as actors for protection against environmental risks. The internet and social networks were the most frequently consulted sources of information (77.7%), which was predictive of a higher risk perception. The possible relation between environmental health risk perception and tweet communication was highlighted by a comparison between the risk perception in the city with the highest number of tweets (Modena) and another one similar for socio-demographic characteristics (Pisa). In conclusion, the results of our study may be of help to strengthen information and education programs: functional health literacy should be taken into account in school programs, to produce a basic knowledge for a better understanding of health and environment. Moreover, mass and social media should be included in planning communication intervention and in verifying their results.