Impact of Phosphate Detergents on Plant Life

Excessive Plant Growth

• The most obvious impact of phosphate detergent use is unusual plant growth, especially in aquatic habitats. The widespread use of phosphate detergents led to the overgrowth of vegetation in lakes and rivers across Europe and North America. Restrictions have reduced this somewhat. Because phosphorus is a nutrient, plants whose growth is naturally limited by a limited amount of phosphorus may grow wildly when the nutrient is available in abundance. While this might appear positive, it radically changes aquatic ecosystems, and may cause other problems, for example the blockage of canals.

Algae Blooms

• Algae use the same nutrients as plants. An excess of nutrients produces a similar result; i.e. excessive growth. In the case of algae, this takes the form of algae blooms in oceanic and freshwater habitats. Unnatural algal blooms turn regions into dead zones, by removing oxygen from the water as the algae die and decay. In freshwater habitats, the excess of algae can block the light to underwater aquatic plants, indirectly harming or killing them.

Plant Diversity

• When nutrients are abundant, it is easy for one species to dominate an area. Phosphate detergents contribute to the conditions one or a few species of plants or algae need to thrive. The result is that these species take over, and other plants are overwhelmed, reducing the overall species diversity of a natural habitat and often causing problems for gardeners, especially in water features.

In the Garden

• A gardener is most likely to introduce phosphate detergents to their garden through the use of greywater. Greywater is water that, although not dirty, has been used for something else, such as washing clothes. If you use a phosphate detergent for your laundry, the used water will be high in phosphorus. Phosphorus won't necessarily have a deleterious effect on your plants or lawn; in fact it might make them lusher. However, there is a risk of the phosphorus leaking into the water table, adding to local water pollution. If it leaks into a water feature, you might experience overgrowth of algae, duckweed or other aquatic vegetation.

• The simplest way to reduce your phosphate use, and the resulting impact on natural habitats or your own garden, is to select low-phosphate or phosphate-free detergents. In some places, such detergents are the only kind available, as governments attempt to combat water pollution. In other areas, select laundry powder, dishwashing liquids and dishwasher detergents marked "green", "eco-friendly" or "phosphate-free". Additionally, use the smallest amount of detergent you need for each wash or task, to avoid adding other chemicals to the environment. If you use a substantial amount of greywater containing phosphate detergents, consider where and how you use it and make adjustments accordingly. For example, discontinue use of such water near a garden pond. You might want to use most of the greywater for plant species that need a lot of phosphorus.