Five students from Vietnam Australia International School in Vietnam won the Best in Region award for their investigation into how varying concentrations of plastic-derived chemicals in soil affect the growth of spinach and coriander.
According to the UN Development Program (UNDP), 79% of plastic after being used either ends up in landfills or nature, while only a small amount is recycled. Inspired by their research, Phùng Phương Anh, Bùi Việt Phương Mai, Dương Hoàng Yến, La Tuệ Lâm Lê and Hoàng Minh Anh wanted to investigate the effects of Nonylphenol (NP) and Dibutyl Phthalate (DBP) – chemicals found in plastics – on common plant species in Vietnam.
The team added the two chemicals into soil at different concentrations – low, medium and high – and then planted the spinach and coriander seeds. They measured the shoot height, germination rate and pH of the soil every five days over 30 days, measuring 8 variations in total:
- 1 control (no chemicals)
- 1 mixed concentration (1 mg/kg of DBP + NP)
- 3 spinach (low, medium, and high concentrations of DBP and NP)
- 3 coriander (low, medium, and high concentrations of DBP and NP)
The students found that NP generally had more negative effects on spinach’s growth, while DBP had lower negative effects, and especially a low concentration of DBP even led to an increase in height. Interestingly, the mixed concentration indicated contrasting and relatively favourable results, in which it increased shoot height and germination rate rather than decreased. Despite this, the team concluded that both can lead to health consequences in humans after consumption, therefore the concentration should be lowered as much as possible.
Speaking on their experience of the competition, Bùi Việt Phương Mai said: 'Growing up in a developing country, I’ve always been passionate about science and helping my community. Participating in the Science Competition this year was a memorable experience that enhanced my lab skills and allowed me to bond with friends who share my enthusiasm. I also gained valuable experience in writing science articles and public speaking. I hope these experiences will support my future scientific career and projects.'