Causes and probable correctives for oxygen depletion fish kills in the Dickinson Bayou estuary: a field study and simplified algal assay.
Frequent oxygen depletion fish kills, caused by dense algal blooms, have occurred during summers in the six-kilometer portion of Dickinson Bayou directly upstream from two sewage treatment plants. These plants are the major contributors of wastes to the bayou. During summer periods of low fresh-water inflow, the treatment plant effluents are carried upstream by tidal action, causing dense algal blooms; algal density is much less above tidal influence and downstream from the plant outfalls. Algal assays demonstrated that if the plants employed chemical coagulation to remove phosphorus, the summer algal densities in the critical six-kilometer portion of the bayou would be reduced to concentrations corresponding to, or less than, the levels found in the rest of the bayou. Such treatment would thereby reduce the probability of summer fish kills.