Gyeonggi says SK Hynix Icheon discharge stream exceeds FAO irrigation guideline
In short
Gyeonggi Province said three rounds of testing of Jukdang Stream in Icheon, which receives discharge from SK Hynix’s Icheon semiconductor plant, found chloride and sulfate ion concentrations above the guidelines the U.N. Food and Agriculture Organization gives for irrigation water, while nine items with domestic standards, including biochemical oxygen demand, were within South Korea’s stream limits. The province asked the Ministry of Climate, Energy and Environment to set management and permitted discharge standards for the two substances, which have no domestic stream or agricultural water limit. The institute said the survey was meant to gauge the effect of discharge from SK Hynix’s Yongin plant on Gosam Reservoir, which the province says will receive similar water from next February.
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Gyeonggi Province said on Oct. 5 that three rounds of water quality surveys of Jukdang Stream in Icheon, which receives discharge from SK Hynix’s Icheon semiconductor plant, found chloride and sulfate ion concentrations above the guidelines the U.N. Food and Agriculture Organization gives for irrigation water. The province said nine tested items that have domestic standards, including biochemical oxygen demand, were below South Korea’s stream water quality limits. [ 1 , 2 , 4 , 5 , 6 ]
At a point 0.4 km downstream of the discharge outlet, average chloride concentration was 731 mg/L and sulfate 1,561 mg/L, according to the Gyeonggi Provincial Health and Environment Research Institute. At 1.9 km the averages were 639 mg/L and 1,338 mg/L, and at 7.4 km they fell to 513 mg/L and 1,060 mg/L, showing concentrations declining with distance. Nearby Bokha Stream, which the discharge does not reach, averaged 71 mg/L chloride and 32 mg/L sulfate. [ 1 , 2 , 4 , 5 , 6 ]
FAO irrigation guidance gives a chloride indicator of 355 mg/L and a usual sulfate range of 0–960 mg/L. Asia Economy reported that FAO warns of “severe restriction” for sensitive crops above 355 mg/L of chloride, and that high sulfate can accumulate salts in soil. South Korea sets drinking water limits of 250 mg/L for chloride and 200 mg/L for sulfate but has no standard for streams or reservoirs used as agricultural water. The province said the two substances are common in natural water and are not known as acutely hazardous, affecting mainly taste, pipe corrosion and gastrointestinal irritation. [ 1 , 2 , 4 , 6 ]
The province said it asked the Ministry of Climate, Energy and Environment to set management and permitted discharge standards for chloride and sulfate ions, and to apply strengthened environmental impact assessment consultation standards to SK Hynix’s Yongin site, a request it said it made on Aug. 13. It said it will keep monitoring Gosam Reservoir and nearby streams. [ 1 , 4 , 5 , 6 ]
The institute said it surveyed Jukdang Stream to predict the effect of discharge from SK Hynix’s Yongin semiconductor plant on Gosam Reservoir. Moon Hee-cheon, acting director of the institute, said that if chloride and sulfate at levels similar to Icheon’s flow into Gosam Reservoir from next February, research and effective discharge management measures are needed. Asia Economy reported that Hancheon Stream currently meets the top BOD grade and Gosam Reservoir falls in the third to fourth TOC grades. [ 1 , 2 , 4 , 5 , 6 ]
Anseong city, local agricultural cooperatives and farmers’ groups have opposed the Gosam Reservoir discharge, citing possible harm to agricultural water and crops, Newsis reported. Governor Choo Mi-ae issued administrative guidance to Samsung Electronics and SK Hynix, including on July 16, telling them to raise process water reuse and cut wastewater discharge; Kyunghyang Shinmun reported that some view the announcement as a move to pressure the government and SK Hynix ahead of the Yongin semiconductor cluster’s construction start next year. [ 1 , 2 , 5 ]
Why it matters
The findings feed a dispute over discharge from SK Hynix’s Yongin semiconductor cluster into Gosam Reservoir, which the province says begins next February and which Anseong farming groups have opposed. Gyeonggi Province’s request for national standards on chloride and sulfate ions could add conditions for large semiconductor plants that discharge into streams and reservoirs.
Key facts
- Gyeonggi Province announced on Oct. 5 the results of water quality surveys of Jukdang Stream in Icheon, which receives discharge from SK Hynix’s Icheon semiconductor plant. [ 1 , 2 , 4 , 5 , 6 ]
- The Gyeonggi Provincial Health and Environment Research Institute surveyed the stream three times, on Aug. 26 and Sept. 2 and 3, and found nine items with domestic standards, including biochemical oxygen demand, below South Korea’s stream water quality limits. [ 1 , 2 , 4 , 5 , 6 ]
- Average chloride concentration was 731 mg/L and sulfate 1,561 mg/L at 0.4 km downstream of the discharge outlet; 639 mg/L and 1,338 mg/L at 1.9 km; and 513 mg/L and 1,060 mg/L at 7.4 km. [ 1 , 2 , 4 , 5 , 6 ]
- Nearby Bokha Stream, which the discharge does not reach, averaged 71 mg/L chloride and 32 mg/L sulfate. [ 1 , 2 , 4 , 5 , 6 ]
- FAO irrigation guidance gives a chloride indicator of 355 mg/L and a usual sulfate range of 0–960 mg/L; South Korea has drinking water limits of 250 mg/L and 200 mg/L but no standard for streams or reservoirs used as agricultural water. [ 1 , 2 , 4 , 5 , 6 ]
- Gyeonggi Province asked the Ministry of Climate, Energy and Environment to set management and permitted discharge standards for chloride and sulfate ions, and said it would keep monitoring Gosam Reservoir and nearby streams. [ 1 , 4 , 5 , 6 ]
- The survey was conducted to predict the effect of discharge from SK Hynix’s Yongin semiconductor plant on Gosam Reservoir, the province said. [ 1 , 2 , 4 , 5 , 6 ]
- Anseong city, local agricultural cooperatives and farmers’ groups have opposed the Gosam Reservoir discharge, citing possible harm to agricultural water and crops. [ 5 ]
Confirmed by several sources
- The Gyeonggi Provincial Health and Environment Research Institute surveyed Jukdang Stream, which receives SK Hynix Icheon plant discharge, three times in August and September 2026, and reported the results on Oct. 5. [ 1 , 2 , 4 , 5 , 6 ]
- Nine tested items that have domestic standards, including BOD, were below South Korea’s stream water quality limits. [ 1 , 2 , 4 , 5 , 6 ]
- Chloride and sulfate ion concentrations in Jukdang Stream were higher than in nearby Bokha Stream, which the discharge does not affect, and declined with distance downstream. [ 1 , 2 , 4 , 5 , 6 ]
- South Korea has no water quality standard for chloride and sulfate ions in streams or reservoirs used as agricultural water; FAO irrigation guidance cites 355 mg/L chloride and 0–960 mg/L sulfate. [ 1 , 2 , 4 , 5 , 6 ]
- Gyeonggi Province asked the central government to set management and permitted discharge standards for chloride and sulfate ions. [ 1 , 2 , 4 , 5 , 6 ]
- Moon Hee-cheon, acting director of the Gyeonggi Provincial Health and Environment Research Institute, said that if chloride and sulfate at levels similar to Icheon’s flow into Gosam Reservoir from next February, research and effective discharge management measures are needed. [ 1 , 2 , 4 , 5 , 6 ]
Still unclear
- Whether the measured chloride and sulfate levels cause harm to crops, soil or people The documents say the two substances are common in natural water and are not known as acutely hazardous, affecting mainly taste, pipe corrosion and gastrointestinal irritation, and no domestic standard exists for them in agricultural water; no assessment of actual damage is given.
- Whether the announcement is intended to pressure the government and SK Hynix Only Kyunghyang Shinmun reported that some view it as positioning ahead of the Yongin semiconductor cluster’s construction start next year; no other document says this.
- Whether SK Hynix or Samsung Electronics responded to the findings None of the documents carry a comment or position from either company.
What local media are saying
Timeline, local time
- Governor Choo Mi-ae issues administrative guidance telling Samsung Electronics and SK Hynix to raise process water reuse and cut wastewater discharge; Kyunghyang Shinmun says further guidance followed in August. [ 1 , 2 ]
- Gyeonggi Province asks the Ministry of Climate, Energy and Environment to apply strengthened environmental impact assessment consultation standards to SK Hynix’s Yongin site. [ 6 ]
- First of three water quality surveys of Jukdang Stream, followed by surveys on Sept. 2 and Sept. 3. [ 1 , 2 , 4 , 5 , 6 ]
- Governor Choo attends a party-government consultation on a 162 trillion won fund and calls for investment in Gyeonggi industrial areas including Yongin, Pyeongtaek and Icheon. [ 2 ]
- Yonhap reports the province’s announcement that chloride and sulfate ion concentrations in Jukdang Stream exceed FAO recommended levels. [ 1 ]
- Kyunghyang Shinmun reports the results and adds that some view the announcement as a move to pressure the government and SK Hynix before the Yongin cluster’s construction start. [ 2 ]
- Newsis reports that the province flagged the need for management standards for chloride and sulfate ions. [ 3 ]
- Hankook Ilbo publishes the detailed concentrations by sampling point. [ 4 ]
- Newsis reports that Anseong’s agricultural sector is watching the results closely amid opposition to the Gosam Reservoir discharge. [ 5 ]
- Asia Economy reports FAO’s crop-restriction wording and the province’s Aug. 13 request for stricter assessment standards for the Yongin site. [ 6 ]
- Hankook Ilbo issues a further summary report on the same findings. [ 7 ]