Enviroment

Ground Water Header

With the Island surrounded by the waters of the Gulf of St. Lawrence and blessed with many freshwater streams, it is easy for Prince Edward Islanders to take clean water for granted. Indeed, Islanders are among the largest water users in Canada. Water is so abundant that we have not felt the need to conserve it. Nevertheless, we do know the importance of protecting it from contamination. Water is vital to human health, agriculture, woodlands, wildlife and diverse types of ecosystems such as wetlands, bogs, salt marshes, coastal sand dunes, beaches, and offshore islands. In addition, our industries such as agriculture, fishing, aquaculture, tourism, and food processing depend on the availability of clean water.

About one third of the 1,100 millimetres of precipitation that annually falls on Prince Edward Island soaks into the earth to become groundwater. Approximately one quarter more joins Island watercourses as surface water. The rest returns to the air through evaporation and transpiration. Stream water eventually makes its way to the ocean, meeting the tide as it travels up the Island’s waterways. The areas where the fresh and salt water mix are called estuaries.

Island groundwater is generally of excellent quality. Water entering the water table seeps slowly through the soil so that many undesirable substances are usually filtered out. But there are many risks posed to groundwater quality. The quality of Island drinking water can be undermined by toxic contaminants including petroleum products, pesticides, nitrates, and manure.

Leaks and spills from petroleum storage tanks and collapsed pipes for fuel tanks used in home heating account for many small spills. Even a small leak, however, can have enormous repercussions as one litre of leaked oil can contaminate one million litres of drinking water. In 1977, for example, 31 Kensington household wells were contaminated by a leaking underground storage tank that had become corroded. Since that incident, the government has required property owners to remove over two thousand steel storage tanks from the ground.

Since agriculture is such an important industry and, by its nature, inextricably part of water cycles, farm related activities can have substantial impacts on water quality. Pesticides can seriously contaminate ground water; especially when large quantities are released or spilled. Under normal use conditions, however, pesticides are very rarely detected in ground water quality tests. On a rare but notable occasion some years ago, a potato insecticide had leached into a community’s ground water. The substance was subsequently removed from the list of approved pesticides and is no longer in use on the Island. However, many factors, such as soil type, tillage and planting systems, irrigation methods, and rainfall patterns influence pesticide leaching. And, more importantly, pesticide use in the province is on the rise.

Similarly, fertilizers both natural and chemical, contain nitrates. Nitrogen in this form can be a common contaminant in Island groundwater due to its abundant use in farming. As the size and intensity of livestock operations increase, so do the risks of water contamination by manure.