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Environment and health
Water quality of the Indus river and its tributaries is excellent. Total dissolved solids (TDS) range between 60-374 ppm (parts per million), which is safe for multiple uses (Bhutta, 1999; PWP, 2000). TDS in the upper reaches range between 60 ppm during high-flow to about 200 ppm during low-flow. Water quality deteriorates downstream but remains well within permissible limits, with TDS in the lower reaches of the Indus (at Kotri Barrage) ranging from 150 to 374 ppm. TDS of some of the tributaries such as Gomal River at Khajuri, Touchi River at Tangi Post and Zhob River at Sharik Weir range between 400 to 1 250 ppm (IWASRI, 1997). The quality of the groundwater is marginal to brackish in 60 percent of the IBIS aquifer. The groundwater quality in the area outside the IBIS varyies, depending on recharge (Ahmad, 2008a; Ahmad, 2008b).
Indiscriminate and unplanned disposal of effluents, including agricultural drainage water, municipal and industrial wastewater, into rivers, canals and drains is causing deterioration of water quality downstream. In 1995 around 12.435 km3/year (9 000 million gallons/day - 1 gallon = 4.5 litres) of untreated water were being discharged into water bodies (Ahmad, 2008b). It was estimated that 0.484 and 0.345 km3/year (350 and 250 million gallons/day) of sewage was produced in Karachi and Lahore metropolitan areas and most of it was discharged untreated into water bodies. The polluted water is also being used for drinking in downstream areas causing numerous water-borne diseases.
Quality of groundwater varies widely, ranging from < 1 000 ppm to > 3 000 ppm. Around 5.75 million ha have underlying groundwater affected by salinity < 1 000 ppm, 1.84 million ha with salinity ranging from 1 000 to 3 000 ppm and 4.28 million ha with salinity > 3 000 ppm. In addition to TDS, water quality concerns are related to the sodium adsorption ratio (SAR) and residual sodium carbonate (RSC) (WAPADA 2006).
Use of pesticides and nitrogenous fertilizers seriously affects shallow groundwater and entry of effluents into rivers and canals is deteriorating the quality of freshwater. Almost all shallow freshwater is polluted with agricultural pollutants and sewage (Ahmad, 2008a; Ahmad, 2008b).
Investments in drainage have been significant during the last two decades, though waterlogging still affects large tracts of land. Soil salinity and sodicity also constrain farmers and affect agricultural production. These problems are further exacerbated by the use of poor quality groundwater (Kijne and Kuper, 1995). In fresh groundwater areas, excessive pumping by tubewells leads to mining and redistribution of groundwater quality (WRRI, MONA and IIMI, 1999).
Waterlogging in the IBIS has been high in the 1990s because of heavy floods. Early in the 2000s, droughts resulted in lowering of the water table and in reduction of the waterlogged area. The overall analysis shows that there is no change in waterlogging. Currently, waterlogged and saline areas are around 7 million ha. During the late 1990s most of the SCARP tubewells were abandoned and farmers were provided support to install shallow tubewells (Zaman and Ahmad, 2009).
Climate change is also expected to significantly affect agriculture. Potential impacts include vulnerability of crops to heat stress, possible shifts in spatial boundaries of crops, changes in productivity potentials, changes in water availability and use, and changes in land-use systems. Even a fractional rise in temperature could have serious adverse effects, such as considerable increase in growing degree days (GDD, which is a measure of heat accumulation used to predict the date that a flower will bloom or a crop will reach maturity). This could not only affect the growth, maturity and productivity of crops, but would also require additional irrigation water to compensate the heat stress (Afzal, 1997).
The quality of shallow and deep groundwater can adversely impact human and animal health. Around 25 percent of all illnesses diagnosed at public hospitals and dispensaries are gastro-enteric and 40 percent of all deaths, 60 percent of infants’ deaths are related to infections and parasitic diseases, most are water-borne. The most common diseases are diarrhoea, dysentery, typhoid, hepatitis, kidney stones, skin disease and malaria.
HIV is not currently a dominant epidemic in Pakistan; however, the number of cases is growing. The World Health Organization (WHO) estimates indicated that the number of HIV/AIDS cases were around 97 000 ranging from the lowest estimate of 69 000 to the highest estimate of 150 000. The overall prevalence of HIV infection in adults aged 15 to 49 is 0.1 percent. The majority of cases go unreported because of social taboos about sex and victims’ fears of discrimination. On the other hand, over 900 individuals receive free HIV medicines and tests from nine public and three private sector facilities (WHO, UNAIDS and UNICEF, 2008).