It was claimed that toxic substances produced by green algae cyanobacteria prevalent in the Nakdong River were also detected in the air of nearby residential areas and tourist attractions. There are concerns that the pollution of the Nakdong River caused by the Four Major Rivers Project is going beyond an environmental disaster and becoming a social disaster.
The Nakdong River Network, the Korean River Society, and the Korean Federation for Environmental Movement held a press conference at the Rachel Carson Hall of the Environmental Foundation in Jung-gu, Seoul on the 21st and announced the results of a survey of microcystin in the air in the area around the Nakdong River. Microcystin is a toxic substance produced by harmful cyanobacteria that cause green algae. The World Health Organization (WHO) International Agency for Research on Cancer (IARC) classified this substance as a possible carcinogen to humans based on animal test results in 2010.
Researchers from Changwon National University and Pukyong National University collected and analyzed samples from the vicinity of Yeongju Dam, Yangsan-si, Changwon-si, Gyeongsangnam-do, and Upo Marsh in Changnyeong-gun, Gyeongsangnam-do from June to November. As a result, the concentration of 4.13ng/㎥ (1 year old) near Hapcheonbo in Changnyeong was found in June. It was revealed that nanograms per square meter of microcystin was detected. Previously, in 2015, social controversy arose when microcystin was identified around a river in New Hampshire, USA, and its concentration was 10.76 to 317.69 times greater than at the time.
Last August, 0.49 to 0.54 ng/㎥ of microcystin was detected indoors in two apartments in Yangsan, Gyeongsangnam-do. In the two apartments, 0.47 to 0.66 ng/㎥ of microcystin was confirmed indoors and outdoors last September. In addition, similar levels of microcystin were detected in a wide range of areas, including a village hall in Gimhae City, a village near Yeongju Dam, a village hall in Changwon City and around Junam Reservoir, and Upo Wetland.
There is still no global standard for microcystin concentration in the air. Through academic papers, cases have been reported in the United States and Australia where this substance spread into the air in the form of an aerosol (a mixture of fine particles in the air) and then was inhaled into the body, causing respiratory diseases. A paper by researchers at Toledo University in Ohio and Oregon State University contains information that it has been confirmed that cyanobacterial toxins in aerosol affect airway epithelial cells.
These organizations announced that microcystin was detected in air collected and analyzed three times from 14 locations along the Nakdong River in August and September of last year. This year, the sample collection locations and number of samples were expanded compared to last year.
These groups claimed, “The negative effects of the Four Major Rivers Project, which was an environmental disaster, are becoming a social disaster due to microcystin contamination of agricultural products due to green algae, total trihalomethane contamination in tap water, a carcinogen, and air pollution due to green algae.” The organizations said, “The family that participated in this measurement is raising a 9-year-old child and 6-year-old twins, and the mother of these children is angry, saying, ‘Children under the age of 10 have grown up exposed to algae toxins from their mothers’ wombs.’” reported.
The organizations continued, “The fact that (microcystin) was detected in an area with dense residential areas and many schools and hospitals shows that not only adults, but also future generations and the socially vulnerable are exposed to risk,” adding, “The government is planning to close the Nakdong River reservoir sluice gate.” “We must not ignore the demand for openness, restoration of nature, and the formation of a private, academic, and public committee to solve the green algae problem,” he argued.