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Cyanobacteria (blue-green algae) bloom on Lake Erie (United States) in 2009. These kinds of algae can cause harmful algal bloom. A harmful algal bloom (HAB), or excessive algae growth, is an algal bloom that causes negative impacts to other organisms by production of natural algae-produced toxins, water deoxygenation, mechanical damage to other organisms, or by other means.
Periphyton can contain species of cyanobacteria that are toxic to humans and other animals. [1] In fresh water, excessive growth and subsequent death and decay of periphyton can have undesirable effects: depleting oxygen in the water, altering its pH, and clogging the space between gravel and sand (the hyporheic zone).
This kills off marine life or forces it to leave the area, removing life from the area and giving it the name dead zone. Hypoxic zones or dead zones can occur naturally, but nutrient pollution from human activity has turned this natural process into an environmental problem. [29] There are five main sources of nutrient pollution.
The toxicity of ammonia is dependent on both pH and temperature and an added complexity is the buffering effect of the blood/water interface across the gill membrane which masks any additional toxicity over about pH 8.0. The management of river chemistry to avoid ecological damage is particularly difficult in the case of ammonia as a wide range ...
Just how common that is varies widely: Anywhere from 10% to 78% of samples of bottled water have been found to contain contaminants that may be harmful to human health. They include:
The risk of dying from chronic lung disease during a heat wave has been estimated at 1.8–8.2% higher compared to average summer temperatures. [36] An 8% increase in hospitalization rate for people with chronic obstructive pulmonary disease (COPD) has been estimated for every 1 °C increase in temperatures above 29 °C. [20]
In humans, arsenic can cause cancer in the bladder, skin, lungs and liver. One of the major sources of arsenic exposure in humans is contaminated water, which is a problem in more than 30 countries in the world. Humans tend to encounter arsenic by "natural means, industrial source, or from unintended sources."
Air pollution can cause diseases, allergies, and even death; it can also cause harm to animals and crops and damage the natural environment (for example, climate change, ozone depletion or habitat degradation) or built environment (for example, acid rain). [3] Air pollution can occur naturally or be caused by human activities. [4]