PHOSPHORUS IN LAKE CHAPLAIN

By:Being Green Pays Firm

Phosphorus Background

Too much phosphorus in water causes algal blooms and excessive aquatic plant growth. These plants and the water quality problems that occur when they decompose can harm fish and other organisms and limit our use and enjoyment of the Lake.

Phosphorus levels are elevated in many parts of Lake Champlain, such as Missisquoi Bay, St. Albans Bay and the South Lake. Nuisance algal conditions exist nearly half of the time in these areas. Blue-green algae has become problematic during the summer in Missisquoi Bay and other northern parts of the Lake.

Algae Background

Algae are vitally important to marine and fresh-water ecosystems, and most species of algae are not harmful. However, a harmful algal bloom can occur when certain types of microscopic algae grow quickly in water, forming visible patches that may harm the health of the environment, plants, or animals. HABs can deplete the oxygen and block the sunlight that other organisms need to live, and some HAB-causing algae release toxins that are dangerous to animals and humans.

Algae Types

There are many types of microalgae, which can be divided into harmless, nuisance micro algal blooms, toxic blue-green blooms, and fish killing events.

Harmless blooms result in water discoloration but have no scum or odor Nuisance blooms occur when harmless microalgae form surface scum's

that may cling to the skin Toxic blue-green algae blooms are potentially harmful if water is ingested

by humans and animals or if they come into contact with people’s mucosa (for example mouth, throat and nose).

All blue-green alga can potentially cause skin irritation following direct exposure.

Blue-green algae usually flourish in waters with high nutrient levels and can result in bright green or khaki paint-like scum along the water’s edge.

When blue-green algal blooms are identified in any recreational waters, health warning signs are erected, and media alerts issued to inform the public.

As a precaution, water contact should be avoided and edible mussels from bloom-affected areas should not be consumed as they can become toxic.

Fish ‘kills’ can be caused by natural conditions, toxic algal blooms, low oxygen levels in the water or pollution events

Causes

CAUSES OF THE EXCESS PHOSPHORUS

WHERE THE EXCESS PHOSPHORUS IN THE LAKE COMES FROM

Detergents Fertilizers Conversion of agricultural and forest

land to developed land Stream erosion Inadequate implementation of Best

Management Practices on farms and in urban areas

This assumption has the convenience that, at least in principal, what has been done can be undone-that in some way it can be possible the water can be returned to a more pristine condition.

Runoff from roads and developed areas

Runoff from farms Runoff from lawns Overflow from septic

systems Non-point sources

contribute to more than 90%

Less than 10% comes from point sources (wastewater treatment and industrial discharges)

Environmental Factors

Global Warming is a factor and is causing an increase in algae One environmental factor weighing on Lake Chaplain is the

summer season. In the rivers and lakes, micro algal blooms usually occur from

spring through to autumn when temperatures are warmer, there is bright sunlight and the water is slow-moving or stagnant.

Under these ideal conditions they flourish, forming blooms. Also, wet months cause more runoff into the lake. Lake Champlain is surrounded by a substantial amount of

agriculture, which means more use of fertilizers to runoff into water systems.

About half of Lake Champlain's phosphorus problem is from developed lands and one acre of urban/suburban land contributes about four times more phosphorus to the Lake than one acre of farm land!

What Phosphorus Does to the Water

High levels of nitrogen and phosphorus in waters can produce harmful alga blooms. In turn, these blooms can produce "dead zones" in water bodies where dissolved oxygen levels are so low that most aquatic life cannot survive. This condition in water bodies is referred to as hypoxia.

The shallower parts of Lake Champlain are the most vulnerable to heightened phosphorus levels and thus the excessive growth of nuisance algal conditions. Missisquoi Bay, St. Albans Bay, and the South Lake have the highest incidence of heightened phosphorus levels.

Possible Solutions and Strategies

Regulate ingredients of fertilizers Tackle sources of nutrients, such as nitrogen and phosphorus, before they

enter the waterways Implement intervention techniques such as oxygenation, which increases

the amount of oxygen in the water column and prevents conditions that enable algae to grow

Implement a Drainage Nutrient Intervention Program to remove nutrients from drains and tributaries before they reach rivers

Homeowners could create buffered vegetated strips along a riverbank Land conservation may be the best solution to this problem (undeveloped

forested land contributes 40 times less phosphorus to the Lake than developed land and about 3.5 times less phosphorus than agricultural land.)

Riparian buffers- A section of trees or shrubs growing between developed or agricultural land and the lake. The roots of the plants help keep soil from washing into the water as well as filtering much of the water that does wash in of any pollutants including phosphorus.

Take efforts to reduce global warming.