This is nonsense, In salt water the discharge of sewage, one flush at a time is 1) insignificant and 2) quickly diluted beyond any health risk. Municipalities have frequently released millions of gallons of sewage and then said it was an insignificant drop in the bucket. How significant do you think one flush is?

This has happened in the great lakes with the same response from the sanitation authorities. Milwaukee used to be infamous for this.

The discharge laws have no basis in fact - they are just over regulation by well meaning but naive legislators.