Lead Levels in Roadside Soil

Lead Levels in Roadside Soil

Aim

Background

Lead is a type of heavy metal and has an atomic value of 82. Of all the known heavy metals in the earth’s crust, lead is the most abundant. It is naturally all around us. Lead poisoning has been linked to many health issues, the earliest reported in 370BC. It became a common illness in people working in industries such as smelting, painting, plumbing and others in the 19th and 20th centuries as these workers were exposed to lead pm a regular basis. (Wu et al., 2011)

High exposure to lead can result in damage to most of a person’s organs and organ systems including, kidneys, blood and the central nervous system. It has the potential to be fatal. Even small doses of lead can damage a person’s psychological and neurobehavioral functions (Wu et al., 2011). Philip J. Landrigan believes that unborn babies and young children are the most at risk of permanent and untreatable damage as a result of exposure to lead. Lead apparently “interferes with neuronal migration, cell proliferation and synapse formation during critical periods of vulnerability” He claims that loss of intelligence and behaviour are the result of this lead interference (2002).

There are many uses for lead in both chemical and metal compounds. One of the compounds of lead is called tetraethyl lead. In 1922 tetraethyl lead was added to petrol with the aim to improve the performance of engines and by the 1970’s most petrol across the globe contained lead. After the damaging effects of exposure to lead were found, along with the damage lead was doing to cars, governments around the world started to take action to remove lead from petrol. By 2002, lead was finally phased out in Australia and 80% of the total sales of petrol was accounted for by unleaded fuel. (Landrigan, 2002)

Due to health concerns of the absorption of lead and the fact that lead stays in soil for hundreds of years it is imperative that the level of lead in the environment be monitored and exposure limited (where possible) for the sake of public health.

Method

A road in a major capital city that had a high traffic flow was identified. Two experiments were then done on the soil samples collected. In the first experiment, soil samples were taken from a spot directly adjacent to the road. The first soil sample was the surface sample. The following soil samples were taken at depths of 5mm, 10mm, 15mm, 20mm and 25mm. These soil samples were then analysed in a laboratory for the concentration of lead. This test involved combining 3 grams of soil with 30 millilitres of HNO^3 for 1 hour at 180 oscillations per minute. The sample was then centrifuged and the supernatant analysed for lead using an ICP-AES (inductively coupled plasma atomic emission spectrophotometer). (Regents of the University Of Minnesota 2016).The results of the lead concentration were reported in ppm then converted to mg of lead per g of soil for easy understanding (Figure 1).

In the second experiment, samples of the surface soil were taken from the edge of the same road as experiment one and at distances of 5m, 10m, 15m, 20m and 25m extending into the neighbouring parkland. The samples were then tested using the same process as experiment one. The results were then converted to mg of lead per g of soil for easy understanding (Figure 2).

Results

Figure 1 shows that the deeper the soil, the lower the lead concentrations, with the exception of the surface soil. The highest lead concentration was found at 5 mm deep with a lead concentration of 0.26 mg/g of soil. The lowest concentration of lead was 0.02 mg/g of soil at 25 mm deep.

Figure 2 shows that the further away from the road the soil sample is taken, the less lead concentration there is in the surface soil sample. The most lead was found at 0 m and had a lead concentration of 0.09 mg/g and the lowest found was at a distance of 25 m and had a lead concentration of 0.01 mg/g.

Discussion

On the basis of analysis as performed, it is discussed about the lead metal, its availability, uses, hazards and its concentration in the soil at different layers. It is discussed that lead is a chemical element with atomic number 82 and symbol Pb.  It is very soft, malleable, ductile and poor conductor of electricity. It is in the carbon group but behaves quite different from carbon. It is discussed that lead as a metal is present in the environment from thousands of years and it is one of the few elements known to ancient people.  Lead generally occurs as an ore and rarely as a pure lead metal. It usually is found as an ore lead sulphide. Also some other ores of lead are zinc, silver, cerrusite etc.

It is discussed that lead has wide applications since 5000 BC.  Lead is generally used in pipelines, cables and also in paints and pesticides. Lead was considered quite safe years ago for its numerous use but now it is understood that it has damaging effects on health of humans and animals. It is highly toxic and enters human body through water, food and air. Some fruits, vegetables, wine; cigarette etc contains lead and through this lead enters our body. It enters our body through drinking water when pipes corrode. It also enters our body when lead fumes and dust are inhaled.

It was found in the early 19^th and 20^th century that people working in smelting, painting etc industry are more prone to health issues due to more exposure to lead on regular basis. Though occupational exposure to lead was a concern but the major concern found in late 1800 in Australia was risk of lead poisoning to children. In children lead exposure and inhalation cause behavioural disruptions, brain damage and it makes difficult for them to carry mental functions normally and thus reduces their learning ability. Lead has the ability to affect brain and kidney. It is very toxic and also causes anaemia, high blood pressures, kidney and brain damage. It also reduces men fertility through sperm damage and in women it leads to miscarriage and subtle abortions. It is so harmful that it harms the nervous systems also. It also enters the mother’s womb through placenta and affects the foetus. Thus it harms unborn children by harming their nervous systems and brains.

It has become evident that lead ends up in water and soil and thus affects water organisms and soil organisms. Highways and farmlands are the areas where lead concentrations in the soil are high and thus here soil functions are disturbed.  Hence pertinent steps are being taken to reduce the consumption of lead as it affects public health highly.

Road side traffic is one of the main reasons for the lead accumulation in the soil adjacent to road. In order to test the concentration of lead at different depth of soil roadside area is considered where traffic is much as vehicles are one of the causes of lead accumulation in the soil. It is evident from many sources that concentration of lead reduces moving away from the road. Thus two experiments are conducted and samples of soil are collected from the area directly adjacent to the road and from the area little away from the road.

The conduct of the analysis revealed significant level of finding with respect to the application of lead and the ways in which it is likely to impact the health condition. The analysis as performed in respect to the soil collected from road side has revealed significant level of findings. It is discussed that the lead concentration in the soil is a major factor, as deeper the soil; the lead concentration is likely to be lower.  The findings lead to discussion that the distance of the road side is a major factor affecting the lead concentration within soil. The experiment as carried out has resulted into discussion that the level of lead concentration is identified as higher especially in respect to the road side. This is clarified from the findings that the distance from the road of 0 km has higher lead concentration in the soil. This is a major threat to the health performance because lead can account to significant level of adverse impact on the health performance of people at large. As a result, necessary precautions are essential from the point of view of performing the management of health condition in a better manner.

Conclusion

References

LANDRIGAN, P. J. 2002. The worldwide problem of lead in petrol. Bulletin of the World Health Organization, 80, 768-768.

REGENTS OF THE UNIVERSITY OF MINISOTA 2016, accessed on 17 March 2016  http://soiltest.cfans.umn.edu/our-methods/#ENVIRONMENTALLEAD

WU, W. T., TSAI, P. J., YANG, Y. H., YANG, C. Y., CHENG, K. F. & WU, T. N. 2011. Health impacts associated with the implementation of a national petrol-lead phase-out program (PLPOP): evidence from Taiwan between 1981 and 2007. Sci Total Environ, 409, 863-7.