A grass roots approach to sustainable
Galveston Bay marinas
Environmental Heath Issues
Environmental Impact of Boater Sewage
Eutrophication is a
process
whereby water bodies, such as lakes, estuaries,
or slow-moving
streams receive excess nutrients such as nitrogen and
phosphorus that stimulate excessive plant growth from algae and nuisance
weeds. This is called an algal bloom. Algal blooms reduce dissolved oxygen
when dead algal plant material decomposes. The decomposing algae can
smother bottom dwelling organisms and low dissolved oxygen and can cause
other organisms to die from oxygen starvation. Water with a low
concentration of dissolved oxygen is called hypoxic.
Hypoxia is common during the summer months when surface water temps are high, surface winds are low and during drought conditions. If you were a fish, this puts you into a “physiological squeeze” between your water temperature tolerance and your need to move some oxygen through your gills. Fish kills often result when fish can’t breathe and/or can’t tolerate water temperature.
Boater sewage discharge
causes eutrophication and
poses human health risks both with adverse
consequences to society. Human waste carries pathogens such as bacteria,
viruses and parasites. People who come in contact with water that has been
contaminated with human wastes can become ill. More serious water-borne
diseases include infectious hepatitis, typhoid and cholera, necrotizing faciculitis (also known as flesh eating bacteria).
Untreated vessel discharges can contaminate shellfish beds. When boaters discharge wastewater overboard in shellfish bed areas, these contaminated shellfish can convey virtually all waterborne pathogens (disease causing organisms) to humans.