A new finalised study that was completed in 2019 has found that the levels of arsenic in children living near a gold mine that was shut three years ago dropped sharply since an earlier study in 2016.
The study corresponded with a significant decrease in learning disabilities that were linked to the children's exposure to the poisonous chemical element.
The study was carried out last year on about 200 Prathom 4-6 students in six schools in Phichit, Phitsanulok and Phetchabun, in areas that surrounded the former location of a gold mine that was shut down three years before that.
It found only 4.5% of these students were found to still have high levels of arsenic, 12 times lower than that (36.1%) found in a previous study carried out in 2016 before the gold mine was shutdown.
Funded by the Health Systems Research Institute (HSRI), the study was carried out by National Institute for Child and Family Development (NICFD) of Mahidol University on the same six schools studied in 2016.
Jointly carried out by the Public Health Ministry and Ramathibodi Hospital, the 2016 study was conducted after a large number of complaints were received from villagers in the area about arsenic contamination in the environment, which was blamed on the gold mine. However, this sharp drop was found across all ages and sexes, said the 2019 study.
The share of a group of 126 students with intelligence quotient (IQ) scores of 90 and higher who still had learning disabilities also fell to 22.22% from 38.9% in the 2016 study.
And in a follow-up programme carried out after the 2019 study on a group of students found to have an average IQ score of less than 90 (85.43), the students were found to have a higher average IQ score of 90.11, which is considered to be a normal intelligence level, the HSRI said yesterday.
The programme was aimed at rehabilitating learning abilities of the low IQ group through enhancing their reading, spelling, sentence comprehension and mathematic skills, said the HSRI.
Assoc Prof Adisak Plitapolkarnpim, a NICFD researcher, said the sharp decrease in arsenic levels in these children was a result of environmental rehabilitation work carried out during the three years after the gold mine shut.
"The government should think more carefully as to how it will prevent children and their communities from exposure to new heavy metal poisoning [that may be caused by new gold mining activities if the mines are authorised to operate again]," said the researcher.
Nopporn Chuenklin, director of the HSRI, said heavy metal contamination in the food chain and the environment actually affects every one, but children are five times more vulnerable to the impact on their health.