The lab under the Division of Environmental Science and Engineering, POSTECH, located in Pohang City, Korea, is a place of much convivial comradery, and yet can be in the very next moment, the site of extreme and studious concentration. Imagine a researcher smiling and chatting about with his colleagues suddenly change his expression to one of seriousness. The researcher holds up a knife and slits the underside of a fish. This fish, caught in the Hyeongsan River in Pohang, is sliced open as the researcher begins to probe for clues deep inside its belly. In this case, a ‘scientific environmental forensic’ was initiated to discover the source of mercury pollution in this local river.

The Environmental & Health Assessment Lab (EHA Lab) directed by Professor Sae Yun Kwon at the Division of Environmental Science and Engineering, POSTECH, carries out scientific investigations to pinpoint sources of pollution in the environment and ecosystem, specifically pertaining to the circumstantial evidence of when, how and to what extent pollution has been released. The Lab also leverages investigation outcomes to predict the impact of climate change or environmental policies on how pollution actually appears within the landscape. Essentially, the Lab is equipped with all-encompassing analytical capabilities to look into the past (cause), the present (phenomena) and the future (forecast).

The EHA Lab engages in the entire spectrum of scientific environmental forensics. Notably, researchers at the Lab are delving into the details pertaining mercury that disrupts the human central nervous system. Mercury was singled out as one of the top 10 pollutants by the World Health Organization due to the intensity of its toxicity and its extremely persistent tendency to linger on in the environment. The primary mode of environmental discharge of this heavy metal includes such anthropogenic activities as coal-fired power generation, waste incineration and cement manufacturing. Once mercury is discharged into the environment, it can never be dissolved, is much more volatile than other heavy metals and can even atmospherically drift into polar regions. Mercury accumulates in the body mainly through the consumption of fish.

Pohang City commissioned the EHA Lab to look into mercury-induced pollution as its first-ever scientific environmental investigation. This project analyzes the mercury accumulated within the fish of Hyeongsan River and traces the type of businesses that discharge mercury into the environment. The main forensics tool here is to study the fish samples for their ‘mercury stable isotope ratios’. Mercury has seven stable isotopes, and their ratios differ depending on their origin. Such differences can enable researchers to track down the origin of mercury and the source of its pollution. In addition, the Lab uses numerical modeling to forecast the future of mercury.

The EHA Lab has built big data on mercury stable isotopes from the data it has accumulated over the years. Such big data have been adopted as the major sources used to assess the progress made under the Minamata Convention on Mercury adopted back in 2017 to impose general regulations on mercury-consuming/discharging industries, their manufacturing processes and products. The mercury big data produced by the Lab will soon be officially registered on the UN website and made available all around the globe.

The EHA Lab plans to go one step further in developing mercury pollution indicators based on the mercury stable isotope ratios calculated within the flesh of fish, with the belief that these indicators may fulfill an important role in easily identifying the sources of mercury pollution within the environment that so adversely impact human health. “For us to develop such indicators, we first need to conduct biological research to understand how mercury stable isotopes change within the body of organisms through the biological metabolic process”, Professor Kwon commented, adding “We will engage in any research that is genuinely engaging, novel and creative that contributes to scientific environmental forensics”.