Complex sentence: Although no known illnesses have been associated with consuming hijiki seaweed to date, inorganic arsenic has been identified as carcinogenic to humans, and exposure to high levels of inorganic arsenic has been linked with gastrointestinal effects, anemia, and liver damage.
Split into simpler sentences: Although no known illnesses have been associated with consuming hijiki seaweed to date, inorganic arsenic has been identified as carcinogenic to humans. Exposure to high levels of inorganic arsenic has been linked with gastrointestinal effects, anemia, and liver damage.