- Water pollution can come from a variety of places, from agricultural and livestock farms to industrial plants. When it comes from agricultural settings, it usually contains high amounts of nitrogen and phosphorus. When large bodies of water are exposed to these nutrients, there is often an unhealthy spike in the plant life -- particularly seen with algae. Algae can spread fast and far, blocking the sunlight and shading plants and animals beneath. If the algae blooms last long enough, it can kill the plants that it overtakes.
When plants take water in through their roots, they also take in nutrients and whatever other chemical compounds are in the water. When the water is polluted, plants can become poisoned with pollution; this can result in visible impacts from yellowing leaves to unhealthy or dying seedlings. - Contaminants in soil can easily pass into the plants that rely on the nutrients contained in soil for survival. If a single area is polluted, contaminants can quickly spread to other areas due to the water that moves through the soil; in many cases, what might seem like a small spill or contamination can spread to the plants in a wide area.
Salts, lead and other heavy metals are commonly found soil pollutants. With a high enough concentration, plants can be killed outright. Those that are not killed often have a slow growth pattern, and contain pollutants which are then passed on to whatever organism, human or animal, consumes them. - The wind can spread particles over long distances in a way similar to water. The largest and most dangerous type of air pollution is smog, which contains a wide variety of chemicals and pollutants including ozone.
Plants are often used as the first indicators that the ozone is reaching dangerously high levels. Leaves of plants damaged by ozone take on a bleached appearance or a layer of metallic-looking brown spots, usually beginning with the outermost leaves first. Other types of air pollution have a similar effect, ranging from lesions developing on the leaf surface to browning, dying leaves. Sulfur dioxide released from energy-producing factories and fluoride from the manufacture of substances from bricks to fertilizer are some of the most common air pollutants that damage plants. - Solar pollution can be thought of as the pollution that exists high and thick in the air, reflecting the sun's rays back into space rather than allowing them to pass through to the earth. While at first glance it might seem like this would have a detrimental impact on plants around the world, there have been studies that suggest exactly the opposite.
The Centre for Ecology and Hydrology in the United Kingdom has come to the conclusion that the existence of this solar pollution enables plants to store and use more carbon dioxide than they would on a clear day. This means an increased oxygen output, a more efficient rate of photosynthesis and ultimately a higher growth rate, in part due to the diffusion of the sun's rays falling over a larger area on the plants.