Rock water, the remedy for rigidity and self-denial, is made by the sun method.
Water can be taken from any healing spring but it must be free of human interference so distant from areas of habitation. This will minimise any water pollution.
Pollution of streams has three major sources – fertilisers, pesticides and acid rain.
Fertilisers are a source of the nutrients nitrogen and/or phosphorous for plants and promote growth so are used in agriculture. Common fertilisers are ammonium nitrate, urea and ammonium phosphate. These are water soluble so are readily washed into streams by rainwater. They can cause algae to grow, blocking sunlight from aquatic plants. The plants die and along with the algae are decomposed by microbes. This depletes the oxygen levels in the water causing other living organisms to die.
Chemical diagram of pyrethrin I
Pesticides are also used in agriculture to control animals or plants which adversely affect crops. One of the most commonly used classes is the pyrethrins. The first examples were isolated from Chrysanthemum cinerariifolium and the compounds are potent insecticides.
So-called acid rain occurs when atmospheric pollutants, such as nitric oxide and sulfur dioxide from car exhausts, react with water to produce acids like nitric acid and sulfuric acid which increase the acidity of rain.
Chemical diagram of oxazepam
Water pollution is more problematic in urban areas where wastewater enters rivers. Some recent studies have looked at the effect of commonly-used prescription medications which can contaminate water. One of the biggest polluters are the benzodiazepines, like Valium and oxazepam. The latter compound has been found in Swedish rivers and was makes fish less fearful and more active.
Anti-depressants like setraline (Zoloft) also have an effect on fish, suppressing territorial aggression and promoting sociability and boldness. However, although in a laboratory environment these effects are beneficial and the fish live longer and perhaps happier lives, in the real world changes of behaviour which make fish more chilled and bolder may lead to them being more likely to be eaten.
Other effects of drugs including Prozac have been seen in starlings. Prozac causes changes in feeding patterns and females show a reduced libido which, in the long term, could affect the viability of the species. There are various possible solutions to pharmaceutical pollution including filtration of wastewater through constructed wetlands but their high cost raises the question of who should pay.