New Perspectives in Science Education

The impact of environmental contaminants in the ecosystems’ and human health has received increasing attention, not only from researchers and health professionals but also from the civil society. This interest is emerging not only in adults, but also in younger generations. One of the noxious chemicals that has received increased attention is mercury, a toxic metal, well known for its neurotoxicity and endocrine disrupting potential [1] has received increased attention in this context. Due to its widespread occurrence, its deleterious effects and persistency, mercury is regulated by the United Nations trough the Minamata Convention that entered into force in 2017 [2]. However, humans are still exposed to mercury in several ways, being the ingestion of contaminated seafood considered as the most important one [1]. Given the high toxicity of mercury, preventive measures to reduce exposure are highly desirable. However, in order to reduce exposure, it is fundamental to first assess exposure levels. In this line, monitoring surveys are particularly relevant. A monitoring survey was implemented at Colégio Valsassina, a high school in Lisbon, Portugal, in order to evaluate exposure levels to mercury. The work was conducted by a group of secondary students (11 th and 12th grade) under the supervision of biology teachers and researchers from the academia following a Inquiry Based Science Education approach (IBSE). Aksela et al. (2010) elaborates the importance of competencies enhanced through IBSE approach such as decision making, critical thinking, adaptability, tolerance and autonomy. The study protocol was approved by the Pedagogical Board and authorized by the Portuguese National Data Protection Commission. A total of 95 students were recruited, with ages ranging from 12 to 18 years. All volunteers answered a questionnaire with specific questions on mercury exposure sources (e.g. seafood consumption, dental amalgams) and provided a sample of their hair. The provided samples were homogenized and grinded into powder before being analyzed by atomic absorption spectrometry with thermal decomposition and gold amalgamation. The precision and accuracy of the analytical technique were assessed by the analysis of human hair certified reference material (ERM-DB001), with relative standard deviations (%RSD) below 5% and recoveries between 85 and 97%. The concentrations of total mercury in hair samples varied between 12.6 and 3314.74 ng g-1, with an average of 1085±661 ng g-1. Overall, 12% of the studied population, exhibit levels higher than the reference dose set by the Word Health Organization (2000 ng g-1) [3]. Significantly higher levels of mercury were registered in students that consumed fish more than once a week; however, given the small sample size, such results should be interpreted with caution.

Keywords: mercury, students, public engagement, citizen science.

References:

1. UNEP, Global Mercury Assessment. 2002.
2. UNEP, Minamata Convention on Mercury. 2017.
3. WHO, Guidance for identifying populations at risk from mercury exposure. 2008.
4. http://www.allea.org/Content/ALLEA/WG%20Science%20Education/ProgrammeIBSE_YORK.pdf.