Kuwait City has an impact on the nearshore marine environment by discharging sewage randomly through short emergency outfalls into the intertidal zone. The effect of the discharged sewage on the biological activity and the chemical characteristics of the relevant intertidal areas, which are controlled by a dry, tropical climate, was studied.
Pore water, tidal water characteristics and nutrient release and transport from the intertidal zone during tidal flushing were investigated in polluted and unpolluted areas. The accumulation of particulate organic matter in the upper, middle and lower intertidal zones was characterized. It was concluded that in addition to settling, a great deal of particulate organic matter entered into the upper tidal sediment by infiltration during high tide and was filtered out by the sediment and migrated toward the low tide zone during the falling tide. The rate of the release of the substances associated with inorganic particulates was controlled by the overall organic load and the microbial activity. Sediment core samples were taken for multistage carbon dioxide treatment, and the results showed a decrease in carbonate-bound phosphates with depth. Photosynthetic productivity observed during the spring showed a close relationship with the sewage discharges and were also controlled by the tidal current. Based on the determination of dissolved nutrients, it was concluded that the limiting nutrient for photosynthesis was nitrogen rather than phosphorous. The release of some heavy metals from the sewage-polluted intertidal sediment was significant, and beachrock development also related to the discharges. The intertidal fauna was impoverished because of the organic sludge.