Lead pollution is one of the most important problems of environmental and occupational origin and is widely regarded as a risk to health. Lead accumulates in the blood, bones and soft tissues and affects the kidneys, liver, nervous system and blood forming organs. The residence times of lead in the body are estimated at 35 days in blood, 40 days in soft tissues, 3-4 years in trabecular bone and 16-20 years in cortical bone.

Several studies indicated that children are especially sensitive to lead because of their greater exposure and as they absorb, retain and show greater damage for a given body burden. Special concern of lead poisoning has been the accumulation of experimental and epidemiological evidence suggesting that lead is a neurotoxin and it impairs brain development in children, even at levels that were considered safe. There is enough evidence to suggest that in many cases, behavioral and developmental problems in children may be linked to exposure to chemicals like lead in the environment. Lead can damage the brain and nervous system and even a low level of lead exposure can cause learning disabilities, intellectual retardation, hearing loss, speech, language, difficulty in concentrating and staying focused and propensity to violence and other serious health effects in children.

Researchers have found that even children with safe blood lead levels (BPbL = 10 ugm/dL or less) had significant brain damage. A recent study has indicated that specially, at five years of age, the children experienced a 5.5 point drop in IQ for every jump of 10 ug/dL in BPbL. The 73% of the children having even very low BPbLs. showed IQ drop. It was noted that as BPbLs increased from one to 10ug/dL, a child's IQ fell by an average of 7.4 points, a far more decline than was seen with higher BPbLs .In developing countries like Pakistan, children with dietary deficiencies are even more susceptible to lead poisoning. According to 1998 population census, 43.19% (55,042,917 children) of Pakistan population comprises children below the age of 15 years. They face high risk due to lead exposure, most likely due to the use of leaded petrol and increase in traffic in the country.

In Pakistan, like many developing countries, the increasing prosperity and population growths are resulting in accelerated growth in vehicle population and vehicle kilometers traveled. The road length, which was about 94,000 kilometers in 1980-81, had increased to 232,000 in 1997-98, indicating an overall increase of 147%. The number of vehicles have jumped from 0.8 million to about 4.0 million within 20 years showing an overall increase of more than 400 %. The average compound growth of vehicles is about 11%. The number of registered motor vehicles mostly employing leaded petrol has increased from 714,940 in 1990 to 1,167,635 in 1998. Vehicle population growth rate being the highest (27.7%) is in Islamabad.

The transport sector is the second largest energy sector after the industry, stimulated by increasing use of road transport at the expense of railway system. Projected fuel consumption for transport sector has been estimated at 40,000 tons of oil equivalent (TOE) in 2050. The consumption of petrol has increased from 828,670 metric tons (1990) to 1,189,042 (1998). According to 1998-99 estimates, 98.47% of total petrol consumption is in the transport sector. Lead compounds are added in petrol to increase the efficiency of car engines and to prolong engine life by reducing knock. In Pakistan, prior to July 2001, the lead content in petrol (Premier Plus) was 0.35 gram/liter, very high compared to maximum lead contents of 0.00 - 0.15 gram per liter in USA and many European countries. Regular, Super Premier and HOBC were reported to have lead content of 0.42, 0.63 and 0.84 gm/liter, respectively

The high content of lead in petrol is a serious issue, as the end product of it is the release of lead into the environment. A few studies have been reported on lead concentrations in ambient air and dust-fall on some sites in Peshawar, Rawalpindi, Islamabad, Lahore and Karachi. The reported lead levels in air (micrograms/cubic centimeter; ug/m3) were found in Karachi (1980 - 81) 0.13 - 0.24; Peshawar (1994 - 95) 0.21 - 0.79 and Lahore (1993 - 94) 0.15 - 8.36. In 1998, a study with 24 hours monitoring on 14 locations in Rawalpindi and Islamabad was carried out to examine the concentration levels of trace constituents in suspended particulate matter (SPM) and to assess the ambient air quality in the twin city. At nine monitoring locations, lead content in total SPM was found to be in the range 0.25 - 0.98 ug/m3. In the remaining five monitoring locations, with excessive traffic or industrial activity, lead content in SPM was found to be in the range between 1.03 - 4.80ug/m3.

These results indicate a very alarming increase and high levels of lead in the ambient air at the sites and time of monitoring. The World Health Organisation/United States Environmental Protection Agency (WHO/USAEPA) guidelines/standards for lead concentration in ambient air are 0.5 - 1.0 ug/cm3 (annual averages) and 1.5 ug/cm3 (quarterly averages), respectively. However, an accurate assessment of ambient air quality of a site/area is difficult without reliable information and comprehensive data on environmental parameters. For a true comparison with WHO or other guidelines that values a continuous monitoring and measurements of air pollutants is essential requirement and needs to be addressed at the earliest by Pakistan's Environmental Protection Agency (Pak EPA).

There are not many studies carried out in the country with specific research and work done on health or other impacts related to air pollutants, including lead. A study carried out in 1990 on 232 students (boys and girls of ages between 3 - 18 years) of two schools in Karachi, indicated mean BPbLs for school children as 38.2 +/- 7 ug/dl, (range 10.4 - 52.2 ug/dl) which was considerably higher than the acceptable BPbLs of 10 ug/dl. The 92% of the children population studied had BPbLs higher than 25ug/dl, which can cause irreversible mental impairment. Nearly half of the children had BPbLs above 40 ug/dl and none had level below 20ug/dl. Five children had the alarming BPbLs of 70ug/dl. No significant differences in BPbLs were observed, between the two groups or between the males and females in either of the two groups, the length of distance traveled by children and the traffic density of children's areas of residence.

In another study carried out in 1994, five hundred school students (374 boys & 126 girls of ages 11 - 16 years) were selected from three schools in Peshawar and their BPbLs were examined. Mean BPbLs of male & female students were found to be 21.2 +/- 8.15 and 16.8 +/- 4.81 ug/dl, respectively., indicating BPbLs among males to be significantly higher than females. 13% of male students showed BPbLs in the range 31 - 50 ug/dl with no female student's BPbL within this range. In contrast to Karachi, where 98% of the studied children population had BPbLs over 20 ug/dl, in Peshawar 32.6% had BPbLs over this limit, which may be due to much higher traffic activity in Karachi compared to Peshawar.

Studies carried out on BPbLs of 400 school going children in Islamabad and Chakshahzad (about 10 kilometers from Islamabad) also indicated children's BPbLs lower than BPbLs observed for the studied children population in Karachi. BPbLs of 230 school students (girls 129 and boys 101 with ages between 5 - 14) from Islamabad were found to be in the range 13 - 32 ug/dl with overall mean BPbL of 22.8 +/- 3.3 ug/dl, in the studied children population. However, unlike Peshawar, no significant BPbLs differences were observed between males and females Children. The BPbLs of 170 school students (88 boys and 82 girls of ages 13 - 19 years) from 20 villages around Chakshazad were found to be in the range 0.2 - 8.6 with overall mean BPbL of 2.38 ug/dl. However, like Peshawar, in Chakshahzad also mean BPbL for males (3.22 ug/dl) was found to be higher than mean BPbL for females (1.49 ug/dl). Low levels in females may be due to their less exposure to the outdoor environment because of the cultural reasons. BPbLs of the studied population in Chakshazad are not only lower than Karachi but are also significantly lower than Peshawar and Islamabad. Chakshahzad is a rural site having comparatively much lower traffic activity, resulting in lower vehicle exhaust and relatively very low lead levels in and around the area. BPbLs higher than 10 ug/dl among the children of Karachi, Peshawar and Islamabad are alarming and children in these areas face high risk due to lead exposure, which may very likely cause many health problems.

Air pollution is one of those complex environmental problems where control through reduction at source is considered most desirable and the only way to prevent the health and other damaging impacts. Once emitted into the atmosphere, unlike other matrix/media, the recycling or re-use of the emitted products from air is almost impossible. To combat air pollution in the country, the government of Pakistan has formulated acts and policies. Pakistan Environmental Protection Act 1997 (PEPA-97) covers air, water, soil and noise pollution. It also includes hazardous waste disposal and motor vehicular pollution. The PEPA.97 under section 11, sub-section (1) strictly prohibits discharge or emission of any air pollutant in an amount, concentration or level of which is in excess of the National Environmental Quality Standards (NEQS). The PEPA-97 under section 15, sub-sections 1 to 3 describes the regulations of motor vehicles.

Pakistan Environmental Protection Council (PEPC) last year approved a National Environmental Protection Action Plan (NEAP) with “Clean Air” as one of the four priority areas of immediate concern. Components of the NEAP clean air program include control of vehicular pollution, industrial emission and indoor air pollution. As part of the vehicular pollution control program, 2,65,000 vehicles (23.7%) have so far been switched over to compressed natural gas (CNG) and over 300 CNG stations set up in the country. Efforts are also being made to promote use of CNG in auto rickshaws (three wheelers) through motivation and incentive schemes.

Under the Clean Fuel Action Plan (CFAP), a phase-wise lead reduction program to provide low and un-leaded petrol in the country was approved in 1999 by PEPC. The main features of the program were:
(a) October 2000 - reduction of lead content to 0.35 gm/L
(b) Introduction of un-leaded petrol in major cities and highways
(c) Reduce lead content to 0.25 gm/L
(d) Reduce lead content to 0.15 gm/L
(e) Introduce un-leaded petrol throughout the country
(f) 2005 - no more leaded petrol in the country.

It has been reported that Vitamin C, if taken in regular doses, have potential for reducing accumulated lead from human body, as indicated by some recent studies carried out in Malaysia and Pakistan. Children (7 - 12 years of age) under study at Karachi were given a 500 mg vitamin C tablet orally after dinner for 24 days. The mean lead concentration in hair, before giving Vitamin C was 12.7 ± 6.6 ug/gm which after treatment with Vitamin C was reduced to 3.9 ± 3.5 ug./gm. The lead concentration of urine samples of the same children were found to be about 45 times higher than the concentration before vitamin C treatment. Similar studies (August 2000 - January 2002) carried out in Ranau, Sabah in Malaysia also indicated 24 - 54% reduction in lead concentration of children hair after vitamin C treatment..

Pakistan achieved “No More Leaded Petrol” target much ahead of the target time. Since July 2001, three out of the total four refineries in the country i.e. Pak - Arab (PARCO), National (NRL) and Pakistan Refinery (PRL) started producing lead-free petrol and the fourth refinery, Attock Refinery (ARL) started production of lead-free petrol in June, 2002. This is expected to subside environmental lead pollution to some extent. However, there is a need to periodically check the quality of petrol supplied to the users for maintaining quality and also in view of petrol smuggled into country, which may be containing lead.

It has been reported that Vitamin C, if taken in regular doses, have potential for reducing accumulated lead from human body, as indicated by some recent studies carried out in Malaysia and Pakistan. Children (7 - 12 years of age) under study at Karachi were given a 500 mg vitamin C tablet orally after dinner for 24 days. The mean lead concentration in hair, before giving Vitamin C was 12.7 ± 6.6 ug/gm which after treatment with Vitamin C was reduced to 3.9 ± 3.5 ug./gm. The lead concentration of urine samples of the same children were found to be about 45 times higher than the concentration before vitamin C treatment. Similar studies (August 2000 - January 2002) carried out in Ranau, Sabah in Malaysia also indicated 24 - 54% reduction in lead concentration of children hair after vitamin C treatment.

Phasing out lead from Gasoline gives substantial economical benefits to the country. A study carried out in USA estimated economic benefit = US $ 17.2 billion per annum by reducing US population's BPbL by 1ug/dl. With the supply of unleaded petrol, problems of lead poisoning due to lead in the environment have not been completely solved. There are other sources of lead exposure, which include old lead pipelines or lead-based solders in water supply systems, old houses/buildings with lead-based paints and lead-based ceramics. There is a dire need to give high priority to further develop and implement policies and measures that facilitate at the earliest a complete lead phase out program in the country.