Volatile phenol, a toxic substance, was detected in water samples collected near the Tianjin Port, the State Oceanic Administration (SOA) said on Tuesday.
Also, minute traces of sodium cyanide were again detected, but at a lower level than the previous day, reported Xinhua.
The results were based on monitoring reports from Monday, according to the SOA.
Two explosions ripped through a warehouse storing hundreds of tons of toxic chemicals on August 12 in Tianjin city of China.
Death toll from the accident has risen to 114, with 692 people hospitalised and 57 still unaccounted for.
