Chemistry of the Great Big Blue: Sewage

"Warning! Stormwater discharge area may be contaminated by discharge from pipe. Swimming is not recommended within 200 feet of this sign during active discharge"

You live on a rural island. You poop. You flush. Does your island have a sewage treatment plant? Is your plant large enough to deal with the influx of tourists that increases the population of your island by an order of magnitude in the summer? Ever stop to look at the metal pipes on your island’s beach to see what was coming out? More than likely, there’s an ocean outfall involved in your island’s wastewater treatment plan. It may only be for overflow, but it’s an option.

What does “ocean outfall” really mean? Well, often it means raw sewage is dumped into the coastal environment that we all love to swim in. Read More

Chemistry of the Great Big Blue: Sedimentation

Sedimentation in the Chesapeake - look at the brown toward the headwaters. Found at

Rocks erode, travel down rivers and eventually in the form of small particles, settle in river deltas and estuaries. Even smaller pieces can be carried hundreds of miles into the ocean. It’s all part of the natural process of sedimentation, but like many other natural cycles, this one has been hijacked by human activities. Development, agriculture, channelization of streams, damming and many other practices change the natural course of sediment in the coastal oceans more than the ecosystem can handle.

These changes can either be a drastic increase in sediment runoff from upstream sources or a complete deprivation of naturally occurring deltas. In addition, many pollutants cling to these sediment particles so that changing the location of the sediment also shifts the location of pollution.

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