HIGHER RISKS

Particulate Matter (PM) Air Pollution
PM air pollution in Cairo for instance exceeds the health - based standards by a factor of 5 to 10. These levels are higher than all other major large cities in the world (WHO/UNEP, 1992) . Industry is likely the major source of PM. Cement, iron, and steel plants in Helwan are probably the largest source (PRIDE, 1994). Other major sources include natural sand and dust, power plants, construction, open burning of trash, and motor vehicles (particularly diesel engines). PM's range from large ones that fall out of the atmosphere quickly, to small particles that remain suspended indefinitely. The small particles are most hazardous, as they can be inhaled deep into the lungs and lodge there.

Health hazards are dependent on the physical nature of the inhaled particles(e.g. irritant effects, altered mucus secretion and flow leading to increased susceptibility to acute infections) and effects related to the particular chemicals comprising the particles (perhaps even including toxic substances involving non-respiratory system organs and function (USEPA, 1986)

Lead (in all media)
Lead is widely present in food, water and air in Cairo. The average lead level in the blood of Cairo men is about 30 micrograms per decilitre. The level of lead in blood was found to be slightly lower for women, both well above the levels in other large cities. The main source of lead in Cairo comes mainly from food and water, though probably much of the lead enters the environment from highly leaded gasoline and lead smelters.
About two-thirds of lead emission in Cairo come from automobiles fuelled with leaded gasoline; the other one-third come from the dozen or so lead smelters in the city (Nasralla, 1993) . Lead from cars is distributed throughout the city, while the smelters have a major impact on their immediate vicinity. Concentrations of lead in Cairo residents' blood, reflecting total exposure from air and other routes, far exceed safe levels. Lead components in the drinking water supply systems (pumps, pipes, storage tanks, and fittings) contribute to potentially significant levels of lead in drinking water. High levels of lead has been found in different food sampling in Cairo. This is derived from crop production soil, irrigation water, and fertilisers containing lead; deposition of airborne lead on foodstuffs as they are grown, transported or displayed for sale; and lead solder used in canning (PRIDE, 1992).
Health Hazards from lead generally include mental development, blood chemistry, kidney functions, nervous, reproductive, and cardiovascular systems.

Lead and Reproductive Health Hazards
The amount of research done the health hazards of Lead and Pregnancy Outcome is abundant.

The incidence of Pregnancy hypertension and increased blood pressure during labour increased with rising level of lead, but not pre-eclampsia (Rabinowitz et al., 1987) .
Preterm labour and late foetal deaths were statistically significantly associated, in a dose response manner, with maternal blood lead concentration at delivery (McMichael et al., 1986) From Saudi Arabia a relationship was found between maternal blood lead concentrations and birth weight of new-borns, and concluded that low levels of lead exposure to pregnant women may be considered hazardous (Al-Saleh et al, 1995) .

Clinically, nutrition may play a role in the reduction of potentially adverse effects from lead during pregnancy, i.e. protection of the foetus against lead toxicity and/or free radical damage through the antioxidant actions of vitamin E and ascorbic acid. (West et al., 1994) Also lower blood lead concentration were observed in women who took iron and folic acid to supplement their diet. (Baghurst et al., 1987)
The placenta is a poor barrier to lead and Cadmium. From Yugoslavia, a study noted a linear relationship between maternal blood lead and umbilical cord blood lead across a wide range of blood lead levels (Grazizno et al., 1990 , Cavalleri et al., 1978 ). Umbilical cord blood lead levels were 80% to 87% of the maternal levels. Cadmium levels in cord blood, as well, was found to be 70% of that of maternal blood (Lagerkvist et al., 1992) .
Blood levels of Lead in pregnant females are naturally higher around smelter plants. In a U.S. Congress report it was estimated that 403,200 pregnant women out of 3.6 million black and white pregnant women were estimated to have lead levels greater than 10 micrograms/dl. This level is sufficient to pose an intrauterine toxicity risk (Crocetti et al., 1990).

Lead tends to deposit in bones, among other tissues, in a cumulative fashion. Chelating agents may be needed to mobilise calcium, and lead from its deposits in the bone, to obtain sensitive assays of body lead burden. In a study from Sweden, it was noted that there is an increase in blood lead concentrations during pregnancy, despite increased blood volume and unchanged or decreasing environmental lead levels. The mobilisation of lead from bone during pregnancy may explain this increase (Lagerkvist et al., 1996)

Microbiological diseases related to environmental conditions are common in Cairo, including diarrhoeal disease, infectious hepatitis, typhoid fever, schist Microbial Diseasesosomiasis, and many others. These diseases cause up to 10 percent of all deaths among the general population and 30 percent of deaths among young children. Environmental factors such as the quality and quantity of water supplies, disposal and treatment of excreta, solid waste collection, and food contamination significantly affect the transmission and persistence of these diseases. However, their incidence is related as much or more to non-environmental factors (e.g., malnutrition, inadequate health care and education, overcrowding in houses, poor domestic hygiene) as to environmental ones.
Although microbiological diseases seems of less direct impact on reproductive health as it seems in other environmental pollutants, its effect on the general female health may be profound. Maternal anemias, malnutrition, impaired general immunity and increased susceptibility to infectious diseases may all contribute to maternal morbidity and mortality. Increased incidence of preterm labour, haemorrhage during labour, postpartum infections are all considered sequel of maternal malnutrition.



MIDDLE RISKS AND MIDDLE/LOWER RISKS

Air Pollution
Air pollution is mainly a problem of large cities. In Egypt, this problem is mainly related to Cairo. Cairo is now one of the most 20 most populated metropolitan areas in the world and the largest city in Africa. Estimated population of Greater Cairo range from about 10-16 million people (mean 12 million). During the past decade population has grown by about 2.3 percent per year (CAPMAS, 1993). Average population density is about 30,000 per square kilometre, more than in Manhattan in New York City (PRIDE, 1994)
The greatest industry concentrations in Cairo are in the Helwan area to the South and Shoubra El-Kheima to the North.
Prevailing winds from the North, most of the year blow pollutants from the industrial zone in Shoubra El-Kheima directly into the city. The three months of southerly winds bring pollutants from industrial Helwan.
Current ambient concentrations for all major air pollutants in Cairo approach or exceed levels that threaten public health. Table 1 show the Concentrations of Air Pollutants in Cairo.
Table 1: Concentrations of Air Pollutants in Cairo.
Pollutant Concentration (ug/m3) U.S. Standard (ug/m3)
Sulphur Dioxide 40-156 annual mean 80 annual mean
Particulate Matter 349-857 annual mean 75 annual mean
Nitrogen Oxides 90-750 hourly means 100 annual mean
Carbon Monoxide 1,000-18,000 hourly means 40,000 hourly mean
Lead 0.5-10 annual mean 1.5 quarterly mean
Ozone 100-200+ hourly maximum 235 hourly maximum

Health Hazards from Air Pollution
In General, although levels of several air pollutants often exceed health standards, they do not do so by as much as particulate matter (PM) (Vida supra). Non-PM air pollutants also generally have less severe health effects and, at levels prevailing in Cairo, often affect only small, particularly sensitive groups (e.g. asthmatics). Ozone seems to have the most significant health impacts and is probably responsible for several days per year of relatively mild adverse symptoms among much of Cairo's population.
Sulphur Dioxide, despite the fact that it exceeds U.S. health-based standards, it has few adverse general health hazards for the population.
Particulate matter (PM) Vida supra
Nitrogen Oxides (Nox) irritates mucous membranes, aggravates pre-existing respiratory illness (asthma), causes coughs, headaches, and shortness of breath.
Carbon Monoxide (CO) causes cardiopulmonary illness especially in individuals in highly exposed occupations (traffic policemen, bus and taxi drivers and garage mechanics). Minimal health problems are expected in the general population including women.
Lead (Vida supra)
Ozone is a respiratory irritant that impairs lung function and leads to lower respiratory symptoms such as cough and chest discomfort. It is significantly hazardous in individuals having pre-existing respiratory conditions such as asthmatics, may increase the likelihood of chronic lung injury, fibrosis, chronic bronchitis and heightened susceptibility to respiratory infections.
Indoor Air Pollution
The most grave in this respect is environmental tobacco smoke (ETS) or "second hand smoke" which has a cumulative effect on foetal weight and pregnancy outcome. Pollutants from cooking stoves (CO, Nox and particulate) are not uncommon especially in poorer communities in Egypt and rural areas deploying kerosene appliances. In some instances, concentration of such substances may exceed outdoor ambient concentrations. Apart from fire hazards such pollutants may cause respiratory irritation, eye infections, neonatal deaths and low birth weight babies. Biological contaminants such as moulds, mites and allergens as well as household toxins, particularly pesticide sprays may cause serious health hazards. U.S. and other studies have suggested that ETS may have carcinogenic compounds (PRIDE, 1994).
Drinking Water Contamination by Chemicals
Despite its upstream course of more than 6,000 KM, the Nile is relatively unpolluted when it reaches Cairo. Cairo dispenses 2-3 million cubic meters of domestic sewage and 0.2 million cubic meters of industrial effluents generated daily. The large flow of water in the Nile (daily flow of 80-150 million cubic meters) provides extensive dilution of pollutants.
After treatment and chlorinated, the drinking water generated from the 16 water treatment plants in Cairo is nearly always clean. However, the crisis lies in the distribution system. In some areas the pressure reaching houses is considered low for consumption, pipe lines are deteriorated in some areas. To compensate for the pressure loss, it is not uncommon for houses to be equipped with power pumps and holding tanks. The negative pressure generated increases the likelihood of infiltration of ground water and sewage into the pipes. Moreover, the tanks are open for contamination by atmospheric depositions, birds and animals.
In addition, chemical contamination of the drinking water especially in Cairo and other large Egyptian cities are not to be neglected. Chlorine, carcinogenic pesticides, heavy metals especially lead have all been detected in varying levels in our drinking water.
Reproductive Health Hazards from drinking water
There were no confirmed evidence of reproductive health hazards from drinking water chemicals. In a U.S. based study, chlorine and trihalomethane (THM) was associated to non statistically significant increase in cases of miscarriage (in high concentrations) (Savitz et al., 1995) . Another American study suggested, although not confirmed, excess spontaneous abortions rates and birth defect in a single incidence of solvent contamination of drinking water in a certain area in California (Wrensch et al., 1990) .
In Cairo, however, the main health hazard from drinking water is lead contamination. Samples from treatment plants revealed lead levels of 6 ug/l. This level went as high as 200-700ug/l when samples were taken from tap water in one of the reports(PRIDE, 1994). This surprising high level of lead in drinking water is considered the MAJOR source of lead contamination for humans living in Cairo and major Egyptian cities and constitutes a major health threat for Egyptian (Cairo residents) including pregnant women (Vida supra). The source of such alarming chemical contamination needs further clarification.
In addition, microbiological contamination of drinking water in some suburban areas and rural communities in Egypt is not to be neglected. Potent water supplies are still not available in a major sector of non-urban areas of Egypt including a large section of Egyptian population (CAPMAS, 1993).
Chemical Exposure and Reproductive Health

A growing body of scientific evidence implicates occupational chemical exposures in the aetiology of human adverse reproductive outcome. The major threat in developing countries, including Egypt, is the lack of knowledge in handling those chemicals ( Paul and Himmelstein, 1988). In a large study including 10,879 pregnant women exposed to various household and agricultural chemicals, it was found that there exists a strong association of congenital malformations with chemical exposure (Gibson et al., 1983) In another study including women who worked as factory workers in chemical industry suggested high rate of low birth weight and short gestation length and infant death (Kallsen and Landgren, 1994) . In another study from the Netherlands, it was clearly stated that Chemical agents of different nature can induce developmental disorders either via the mother or perhaps the father. The common consent that the vulnerable stage of development is only the first trimester is incorrect. From oogenesis and spermatogenesis to at least the first years of life the developing organism is susceptible to harmful effects of chemical agents, including drugs. Developmental disorders include not only malformations visible at birth, but also spontaneous abortions, foetal death and functional deficits (Peters, 1993) . Spermatogenic count deterioration, loss of sperm motility, teratospermia, loss of libido have all been related to males exposed to chemicals (e.g. solvents). Moreover, increased rates of abortion, stillbirth, low birth weight, and birth defects and childhood malignancy in offspring has all been recorded in wives of males working in chemical industries (Tas et al., 1996)

Pesticides Exposure and Reproductive Health
Organochlorines including endrin, dieldrin, lindane, and DDT were the most widely used pesticides in Egypt through the early 1980's (Abdel Gawaad, 1989) . The hazard from these pesticides is that they are very persistent in the environment and bioaccumulative in fatty tissue. The increasing use of household and agricultural pesticides still constitute a major health threat especially in injudicious use. In Egypt, chlorinated hydrocarbons (DDT) are still in use in some rural agricultural areas. Pesticide food contamination may be a major health threat to the general population in Egypt. Varying amounts of pesticides applied to crops in the field may remain on food surfaces or be incorporated systemically into the plant. Subsequent washing, processing, and cooking may remove some but not all of the pesticide residue. Pesticides may applied to crops after harvest (DDT) to prevent spoilage during transport and storage. Pesticides may even appear in crops to which they were not applied when irrigation water that has been contaminated by upstream pesticide use is re-used for additional crops.

In one study, exposed pregnant women retain high serum levels of such insecticide (DDT) in their serum. In addition, significant residue levels were detected in the cord serum of their babies (D'Ercole et al., 1976) . Another study dealing with DDT, as well, confirmed the placental transfer of this insecticide in humans (Saxena et al., 1981) . From Nairobi, Kenya came a study indicating that DDT was detected in maternal subcutaneous fat, mothers milk, and maternal serum in significant amounts. This in addition to its presence in the umbilical serum (Kanja et al., 1992) . From Nigeria came a study correlating maternal exposure to household chemicals and neonatal jaundice. Naphthalene exposure was the most potent of these chemicals in causing severe neonatal jaundice (Familusi and Dawodu, 1985)
Marked impairment of spermatogenesis was found related to men exposure to the pesticide 1,2-dibromo-3-chloropropane (DBCP) (Marshall et al., 1978 , Levine et al., 1983 , Egnatz et al., 1980 ).