Clam survival fell and antioxidant markers flipped after two weeks of intermittent 50 Hz exposure at 15 microtesla, Chinese study reports

October 20, 2026 (EMFS)

Oct 18, 2026 (original)

Source: Comparative Biochemistry and Physiology Part C

Source category: Research

Researchers in Jiangsu, China exposed the clam Cyclina sinensis to a 50 Hz magnetic field of 15 microtesla, two hours on and two hours off, for either 24 hours or 14 days. Survival was 100 percent in controls, 95.6 percent after the short exposure and 90.0 percent after the long one, and the antioxidant pattern reversed: the short group raised two protective enzymes and lowered a marker of lipid damage, recovering within 14 days, while the long group did the opposite. The authors disqualify their own gene-expression result, writing that without time-matched controls the thousands of altered genes cannot be attributed to the field alone. The same team reported similar effects at graded field strengths in June.

Exposure note: The exposed animals sat in a 50 Hz magnetic field measured at 15 ± 1 microtesla, switched on and off in two-hour blocks, for either 24 hours or 14 days. Controls were kept in the geomagnetic field only. Physiological measurements were taken at 0, 1 and 14 days after exposure ended with time-matched controls at each point, but the transcriptomic comparison had a control only at day 0, which is the gap the authors say invalidates attributing the gene lists to the field.

Quotes

"Rapid expansion of coastal wind farms raises concerns about extremely low-frequency electromagnetic fields (ELF-EMF) affecting marine organisms."

— Zhang et al., Comparative Biochemistry and Physiology Part C (2026)

Exposure

"Using Cyclina sinensis as a model, this study examined effects of short-term (24-h intermittent exposure, 2-h on/off, then field-free recovery to day 14) and long-term (14-d intermittent exposure, 2-h on/off) ELF-EMF exposure (15 ± 1 μT, 50 Hz) versus geomagnetic control."

— Zhang et al., Comparative Biochemistry and Physiology Part C (2026), Abstract

Location

📍 China