2. Drinking-water

    Safe drinking-water is clear, colourless, odourless, of agreeable taste and of reasonable temperature. It contains only small amounts of minerals and a maximum of 0.15 g/litre of lime salts. It should be free of ammonia, nitrates, organic pollutants, and toxic substances such as lead salts and arsenic, as well as poisonous gases. It is totally free of parasites, ova and larvae, as well as disease-causing germs. It may contain no more than 100 non-pathogenic germs per one cubic centimetre.

    Polluted water is that which contains inorganic chemicals, organic matter resulting from degeneration processes, or disease-causing germs or parasites. Polluted water is often turbid, with a particularly unpleasant odour and taste. However, water may remain colourless while containing a large number of pathogenic germs. These require special methods of detection.

    Among the most important sources of rainwater pollution are the particles it collects from the air while falling, and the dirt in the containers in which it is collected. Surface water, likewise, becomes polluted by decayed substances, waste material or dirt that may be discharged into it. Underground water becomes polluted if dirt filters through and reaches the water from a nearby waste dumping site, latrine or the like.

Polluted water and the transmission of disease

    The diseases transmitted by contaminated water are numerous. Prominent among these are the diseases caused by germs or parasites found in the faeces and urine of sick persons, particularly typhoid, schistosomiasis and various kinds of helminthiasis.

    Typhoid-causing bacteria infest man's intestines, blood and urine and are, therefore, likely to be transmitted to water if a sick person evacuates his bowels or urinates into it. In fact, before the adoption of modern methods of purification and control, water was one of the main pathways for the transmission and prevalence of typhoid. It remains so in developing countries.

    Schistosomiasis is characterized by an inflammation of the bladder (demonstrated by haematuria) or the colon (demonstrated by dysentery). In the former, the ova of the parasite are excreted with the urine, and in the latter they are excreted with the faeces. When they reach water, particularly that with little movement, larvae hatch and enter snails, where they develop into cercariae. These swim freely in the water until they come into contact with a person who may be bathing, swimming, washing clothes, drinking or wading in irrigation water. They penetrate the skin of that person with their front extremities, discarding their tails. In 24 hours the cercariae reach the blood and circulate in the blood-stream until they finally enter the liver. There they grow, reach adulthood and multiply. They then migrate to the walls of the bladder and the intestines where they produce ova.

    This noxious cycle continues as long as urination and bowel evacuation are done in such a way that urine and faeces reach surface water, particularly where it is stagnant. The cycle can be broken by teaching people to refrain from such unsanitary practices, which are emphatically forbidden by Islam as will be shown later.

    Ancylostomiasis is caused by worms which are found in the intestines and which inflict acute abdominal pain on the patient. Subsequently, severe anaemia is induced, causing the mucous membranes to become very pale, the face to swell and the legs to become oedematous. The patient may develop oedema, which causes liquids to accumulate in the tissues and body. If the case is not treated, it will certainly lead to chronic debility, and oedema will spread into all the patient's limbs. The patient becomes very lean and bony, yet retains an enlarged abdomen until death.

    The ova of these worms are excreted with the faeces and, if they find damp soil, such as in fields, farms or mines, they hatch into larvae. When a person comes into contact with the larvae, they penetrate the skin and move inwards until they reach the blood and through the blood circulation reach the liver, the lungs and the intestines. Those who are most susceptible to infection are farmers and mine workers. However, larvae also attack children who wade barefoot in polluted mud. Obviously, prevention of the disease requires that no excreta be deposited on the ground, particularly in the shade, as shade maintains the dampness necessary for the survival of larvae, preventing the purifying effect of the sun from reaching them.

    All the foregoing makes it absolutely lear that prevention of water pollution and the spread of the aforementioned diseases depend to great extent on two things: firstly, preventing the pathogenic germs which transmit these diseases and the parasites carrying them from being deposited in water or damp soil; and secondly, not exposing oneself to these germs and parasites by going through polluted water. Stagnant water represents the greatest risk in this connection.

    These are exactly the same measures of control which the Prophet PBUH mentions in a number of authentic statements, or hadith.

1. "Let no one of you urinate in stagnant water" (related by Ibn Majah).
2. "God's messenger has prohibited anyone from urinating where he bathes" (related by Abu Dawood).
3. "Do not urinate in stagnant, unrunning water, then use it for bathing."(related by Muslim).
4. "Let no one of you bathe in stagnant water to remove the state of ceremonial impurity" (related by Muslim).
5. "Guard against the two practices which invite people's curses". When the Prophet PBUH was asked what these practices were he said: "Evacuating one's bowels by the roadside and in the shade" (related by Muslim).
6. "Guard against the three practices which invite people's curses: evacuating one's bowels near water sources, by the roadside and in the shade" (related by Abu Dawood).

    From these pronouncements by the Prophet PBUH , we learn that it is totally forbidden to urinate or defecate anywhere which is considered a source of water (hadith 6). This is particularly emphasized, in the first, third and fourth hadith, in the case of stagnant water, which, as we have learnt, is the best environment for the breeding of parasites. The Prophet's PBUH pronouncements, particularly the second one, also forbid urination in water to be used for bathing. The Prophet's PBUH statement is meant to arouse people's disgust at the unhealthy practice of urinating in water. It reminds us that we may use the same water at a later time for taking a bath or washing. Also, it is a preventive measure, which aims to protect other people against infectious diseases. Urination in stagnant water, including ponds and swimming pools, causes the spread of diseases.

    The Prophet's PBUH pronouncements also prohibit defecation in the shade. From the social point of view, this prohibition highlights the repugnance with which such a habit is held. It is in the shade that people rest, and they are prevented from doing so when they see that the place has been used as a toilet. As far as health protection is concerned, the prohibition is highly significant, because shady places do not receive enough sunshine to kill the germs which happen to be in their vicinity.   It has already been mentioned that humidity, which is indeed for the breeding of ancylostomiasis and various kinds of helminthiasis, lingers on in the shade. 

    The prohibition of urination and defecation in water may be extended to all water pollutants that may have an adverse effect on human health.   These include the disposal of industrial effluent, dead animals, rubbish and waste, as well as the washing  contaminated clothes in rivers, canals and drains, and any action that pollutes the environment and endangers animals and plants. God commands us in the Quran: Do not corrupt the earth after it has been set in order (7:85). He also denounces any person who, whenever he holds a position of influence, goes about the earth spreading corruption and destroying crops and livestock. God does not leave corruption (2:205).

    Islam's concern for maintaining the purity of water is clearly expressed by the following statement by the Prophet PBUH : "Anyone who wakes up from sleep must not put his hand in any utensil until he has washed it three times; for he does not know where his hand was during his sleep" (related by Muslim).