periodic table graphic

- a Review

Good old number 15 on your Periodic Table. Chances are, you now know more about this element than you did during your high school chemistry class. You don’t think so? Let’s review.

Phosphorus is a naturally occurring element and a nutrient essential to the growth and development of organisms. A moderate amount of this nutrient is important to promote a healthy, balanced lake, but excess phosphorus acts as fertilizer and promotes nuisance algal growth. We also know that phosphorus input into our lakes comes from various sources in the watershed, and that controlling input is key to good lake water quality.

Hopefully you are also aware that the state is working to develop criteria that will determine when lakes in the state have too much phosphorus. Once a lake is determined to have too much phosphorus, it is placed on the state’s 303(d) impaired waters list. This leads to the creation of a Total Maximum Daily Load (TMDL) study that initiates a plan to reduce the phosphorus within the lake.

One key to a successful TMDL is accounting for all sources of phosphorus in the lake. Although we have discussed nonpoint sources of phosphorus in previous issues of The Water Line, this issue will expand your knowledge of this nutrient. Phosphorus From Within introduces the concept of internal loading, phosphorus that comes from the lake’s bottom, while Phosphorus by the Numbers discusses the amount of phosphorus coming from agricultural and urban areas. We will also outline various approaches to setting phosphorus criteria and review the pros and cons of each.

Back to the Fall 2006 Water Line

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