Lead as a Pollutant
Lead contamination has become a global problem, characterized by increased levels of lead in the blood of people living in contaminated spots. Lead poisoning was first indicated in 370 BC and from then, its effects have been spreading. Lead traces have also been found present in water, soil, air, and any environmental components. Depending on its level, in a particular area, lead can have mild to fatal effects. Children are the most affected but adults are affected to. Lead contamination and poisoning can stem from various sources such as house dust, gasoline and lead paint. Drinking water, food and soil, are also other sources. People who work in industries, which produce car batteries and other production lines, which involve lead are also at a greater risk of suffering from lead poisoning. Such companies also aggravate the concentrations of lead in the environment, when they dispose waste (Aboh et al 8).
This paper looks at the lead pollutant from a historical perspective. It traces its accumulation right from the prehistoric times to the present past. It looks at how industrialization increased the levels of lead in human blood. In addition, it shows the difference between the blood lead levels then and today. The paper proceeds to outline the recent studies, which have been conducted about lead for the past few years. What to the developments mean for the lead control strategies? It looks at some of the studies conducted in Europe, Asia, Latin America and Africa among other regions of the world and the results. The paper also outlines some of the regulations laid down by EPA and some governments, in an effort to manage lead contamination. Lastly, the paper gives a number of recommendations, which can be used mitigate lead exposure, poisoning and contamination. It proposes recommendations to both individuals and authorities involved in public health and environmental management.
Historic Background Information
Lead is a highly versatile metal, which has been in use since prehistoric era. Over the years, the non-essential element has been distributed and accumulated in the environment, increasing exposure and uptake by humans and other living things. When people are exposed to lead for a long time, their organs and organ systems may be damaged. Blood, kidney and the central nervous system are the most affected and in some cases, death is inevitable. If one is exposed to low concentrations of lead, their biochemical processes, can be affected, their psychological functions disrupted and other effects (Tong, Shirnding and Prapamontol 1068).
Lead exposure and poisoning dates back to historic times. In the Roman era, it was common since people used water pipes, wine storage containers and earthenware, which had lead. Hence, their water was laden with lead traces (Tong et al 1068). As at 4000BC, Egyptians, Phoenicians and Hebrews, were already using lead. Spain also used lead by 2000BC (Hernberge 244). Lead poisoning from occupational activities was reported for the first time in 370BC. Hippocrates was the first to report lead poisoning, although he did not know it was lead poisoning (Hernberge 244).
In the 19th and 20th centuries, workers in occupations such as plumbing, painting, smelting and printing among others, were exposed to lead. In 1767, Franklin requested for a list of all patients, who had been admitted with unexplainable symptoms at the La Charite Hospital. While the symptoms were not recognized, they depicted lead poisoning (Tong et al 1068). Upon industrialization, the levels of lead in the environment increased. Before industrial revolution, the levels were low but after, the exposure of human to lead has risen. The concentration of lead in the environment today, is higher than that of other non-essential elements (Tong et al 1069).
At the global level, immense processing of lead ores, have been estimated to produce about 300 million tons of lead into the world ecosystems over the past 500 years. The invention of motor vehicles in the 20th century did not help to lower the levels of lead in the environment either. Owing to the intensive use of lead-based petrol, there was significant increase of lead. This increased human and animal exposure over the century (Tong et al 1069).
The consumption of lead increased at a steady rate from 1965 to 1990, when it hit 5.6 million tones. During the period of 1980 and 1990, lead usage in developed economies rose only slightly whereas in the developing nations, it increased from 315000 to 844000 tons per year. Lead contamination globally, which is attributed to the heightened accumulation of the metal in water, soil and air due to anthropogenic activities, is still significant to date (Tong et al 1069).
Tong et al (1069) affirms that there is a difference in the lead levels in human blood during pre-industrial era and after industrial revolution. At the time, the level of lead in blood is stated to have been around 0.016mg/dl, which is about 50 to 200 times, the lowest reported level for today’s people. This is especially in remote areas of southern and northern hemispheres, which measure 3.20mg/dl and 0.78mg.dl respectively. The ancient lead level in human blood is also 625 times higher than what the Centers for Disease Control and Prevention in the U.S.A. (10 mg/dl), propose. From the anthropology collections, the lead levels in the remains of the ancient men, is 500 to 1000 times lower than today’s levels.
It is evident that lead poisoning and contamination has been on since the pre-historic times. The industrial revolution only aggravated the level of lead in the environment. The metal has been mobilized, accumulated in water, air, and soil, such that all components of the ecosystem are threatened (Kinder).
Lead poisoning and contamination have been identified as one of the most pressing challenges of most governments and public health agencies. While there has been several occupational and health measures, which the authorities have undertaken, lead exposure is still a problem. To humans, lead has been proven to cause damaging effects on the reproductive, renal and the central nervous system (Flora, Gupta and Tiwarri 47). Besides, lead contamination in the soil, water and air have not been easy on the ecosystems, both fauna and flora have been contaminated (Kinder).
While most people associate gasoline, to lead contamination, there are many other sources of lead. Environmental lead stems from a wide range of sources including occupations, environment and domestic activities. Evaluating the contribution of each of the sources, often poses complexities. It varies between locations and groups of people. Currently, studies have been conducted to determine the susceptibility of people to lead poisoning. Experts have conducted analyses on ALAD gene polymorphisms as well as by use of phenotypic estimations on blood lead-level. Such studies have been conducted in Saudi Arabia, Senegal, Nigeria, Portugal and Latin America among other countries (Shaik, Sultan and Alsaeed 3).
By studying the ALAD gene polymorphisms, which affect lead poisoning susceptibility, has enabled experts in human health to establish persons who are at risk. This way, they will be in a position to prevent both non-occupational and occupational hazards, caused by lead. Globally, studies have been carried out to find out if ALAD gene polymorphisms have a role in lead contamination and toxicity. The studies involved persons who worked in environments, where lead was used. It also included people from the population, who were exposed to lead by being near factories, which released lead or those who worked in such factories but took administrative and management roles. Estimations of gene polymorphisms were also conducted on children as well. In most of the studies, those who had occupational exposure recorded a blood lead concentration of about 10 to 61 ug/dl (Shaik et al 4).
Most studies that were conducted on the general population both on children and adults, with environmental exposure, registered lead levels lower than 10ug/dl. The studies were conducted primarily on the Asian and Caucasian populations. From the results, those with ALAD2 had high lead levels in their blood whereas those with ALAD1 had lower levels. These studies showed that it is important to categorize subjects depending on their genotypes. Such data will enable researchers and health care experts in coming up with preventive measures, in particular for those who are at the risk of lead poisoning (Shaik et al 5).
Other studies have been conducted in the recent years, to find out about the hotspots for lead pollution, especially where children are most affected. Nigeria and Senegal have reported high levels of lead in children, which points out to that children are at risk of lead toxicity. Where remediation measures have been made, the lead levels have dropped very low. For instance, at a blacksmith’s site in Haina Republic of Dominican in 1997, the lead levels averaged at 60ug/dl. However, after the remediation was done the average dropped to 12ug/dl by 2010. Some other hotspots, which were identified, included Central Asia, Eastern Europe, Middle East and Africa. Southeast Asia, South America and Pacific Islands, have also been established as hotspots. Today, most studies are directed into finding the level of lead in human blood, to inform the right prevention and mitigating strategies for lead exposure and toxicity (Clune, Falk and Riederer 21)
Metal smelting was the most common source of lead in a large number of the hotspots. Battery recycling and leaded gasoline, are other key sources of lead contamination. Lead –based paint and glazed pottery are other sources of lead in these regions. By understanding these sources, experts and public health officials, can develop the right strategies for preventing and mitigating lead contamination (Clune et al 21)
Most countries have laid regulations for managing lead contamination. EPA (Environmental Protection Agency) is mostly referenced, when it comes to environmental standards. EPA enacted, the Safe Drinking Water Lead and Copper Rule act in 1991. The LCR accepts a concentration of 15ppb of lead in a liter of water, gotten from the pipe for around 6 hours. EPA also has a goal to put lead levels to a minimum and if possible to a zero. This is the level at which, no deleterious effects can happen (Brown and Margolis 2).
But, EPA understands that reaching this goal can be challenging. This is because, there are multiple sources of the lead in water, which water suppliers for public drinking water, do not have control over. The act requires that water authorities to examine the content of lead in drinking water from residential taps and pipes, made with lead and copper plumbing materials. If more than 10% of the samples of water collected from the water terminal, providing water to around 50000 people surpass the lead action level, treatment for corrosion should be applied. It is the responsibility of the public water providers, to educate the water users on the concentration of lead in the drinking water (Brown and Margolis 2).
Those water utilities that go beyond the action level, should warn the consumers about the risk of suffering adverse health risks. The education materials should contain information about the sources of lead, the effects and the measures individuals can take to minimize lead exposure. LCR still demands that extra action be undertaken, if a water utility with lead-based pipes and corrosion control treatment surpasses the action level, in more than 10% of the collected samples. Apart from creating awareness about lead poisoning, the water utility companies must replace lead pipes. The only portion that the company is not supposed to replace is the one, which is privately owned (Brown and Margolis 9).
After water utility company changes the service lines, they do some tests after 72 hours. The results should be communicated to the customers. Most water systems in the U.S comply with LCR. A report released in 2004, indicated that the levels of lead in water systems, was no longer high. For water utilities serving more than 50000 people, 27 of them (3.6%) were beyond the allowable level of lead at one time. However, lead pipes are still prevalent in the U.S, some of which were laid down between 1800s and 1986 (Brown and Margolis 9).
However, present changes in disinfection and water treatment procedures can significantly undermine the control of lead corrosion. In the early 90s, in District of Columbia, chlorine was used in high concentrations, to reduce coliform bacteria. The process affected the lead coating along the water piping, making it to be insoluble. When the chlorine was substituted with chloramines, the insoluble scale of lead became unstable and dissolved. Hence, significant concentrations were released (Brown and Margolis 9).
To this effect, CDC conducted a research, to establish the relationship that existed between methods of water treatment in District of Columbia, lead in water pipes and lead levels in blood of children from 1998-2006. The study found out there was a correlation between high BLLs in children and presence of lead in the pipes. This was clear especially during the period of 2001 to 2004, when chloramines were applied as water purifiers without adequate corrosion treatment (Brown and Margolis 9).
While regulations on drinking water have been given maximum attention, EPA has also established more regulations to prevent the accumulation of lead in the environment for the sake of wildlife too. Besides, it has put forward measures, to prevent and remediate lead hotspots to prevent them getting into water systems, plants and to the atmosphere (Kennedy et al, 23).
Recommendations for Less Exposure to Humans and Wildlife
Exposure to lead for both humans and wildlife can occur through various ways. First, one can ingest lead through drinking water and food. This can apply for the wildlife too. To prevent ingestion, there should be policies, which are geared towards preventing lead based products from reaching the consumer. Such can be food additives, water systems and cosmetics. If the lead contents in the products get into the body, they might harm vital body organs. FDA for example demands that products should be made clearly packaged and labeled, so that the consumers can know the ingredients of the products. Authorities for testing the standard of various products should also be vigilant into ensuring that what gets to the consumer is healthy (Ettinger and Wengrovitz 67)
People should avoid taking water, which is contaminated by lead. Usually, lead contamination in water is caused by lead-based water systems. In this era, the ancient lead pipes should be replaced with PVC piping. Today, there is intensive recycling of polythene and plastic. Hence, this will not be an expensive venture. Lead pipes have been known to increase the action level from the proposed 15ppb. If substituting the pipes is not an option, then if people must use the water, it must then be treated and flushed prior to use. This is one way of reducing the risk of exposure and mitigating its health risks (Ettinger and Wengrovitz 68).
Apart from lead ingestion, humans as well as wildlife can be exposed to lead through the environment they interact with. It is the duty of every human being to reduce the accumulation of lead in the environment. Although EPA agrees that the action level cannot get to zero, it can at least remain manageable. Humans are notorious for causing environmental degradation. Therefore, they should be in the front line of mitigating the effects. They can do this, by avoiding lead-based paints and practices, which develop dust laden with lead traces. Property owners should disclose information about the building materials and the paints used in the properties, to minimize exposure. This way, they will be in a position to make sound decisions (Ettinger and Wengrovitz 69)
Lead-based construction materials should also be disposed appropriately. This will prevent the elements from reaching various systems of the natural environment. High concentrations of lead can cause damaging effects in animals as well. There might not be adequate statistics and information about the effects of lead on wildlife but it is expected. They may not be affected directly but the effects may be spread across the food chain (Ettinger and Wengrovitz 69)
Lead based gasoline has also been a cause for lead contamination. It is the right of a consumer to know what they are using. Although most countries today have done away with lead-based fuels, in some places, the gasoline is still in use. As mentioned earlier, lead has diverse entry points into the human’s body. Lead from car gas can get into the air, thereby getting into the body through inhalation. Lead based gasoline, should be eliminated in the stores. There are more eco-friendly options. They might cost more than the lead based fuel, but they will ease the risk of lead exposure and poisoning (Ettinger and Wengrovitz 69)
Finally, based on the studies carried out in different parts of the world, they have shown that industries, which use lead or produce lead, are to blame for heightened lead levels. Since, lead is a versatile metal, it would not be appropriate to shun its use all together, but it can be controlled. Such companies should be located far from residential places. Furthermore, they should be regulated to ensure that they do not dispose their lead waste to the environment (Briggs 20).
Aboh, Innocent, Sampson, Manukure, Abra-Kom , Leticia, Caravanos, Jack, Ofosu, Francis and Harriet Kuranchie-Mensah, Harriet. Assessing Levels of Lead Contamination in Soil and Predicting Pediatric Blood Lead Levels in Tema, Ghana. Journal of Health and Pollution 3(5), pp. 7-12, June 2013 web. 1 Dec 2015 <http://www.journalhealthpollution.org/doi/full/10.5696/2156-9614-3.5.7>
Briggs, David. Environmental Pollution and the Global Burden of Disease. British Medical Bulletin Journal, 68(1), 1-24). 2003 web. 1 Dec. 2015http://bmb.oxfordjournals.org/content/68/1/1.full
Brown, Mary and Margolis, Stephen. Lead in Drinking Water and Human Blood Lead Levels in the United States. National Center for Environmental Health, 61(04), 1-9, 10 August 2012 web. 1 Dec. 2015 < http://www.cdc.gov/mmwr/preview/mmwrhtml/su6104a1.htm>
Clune, Alison, Falk, Henry and Riederer, Anne. Mapping Global Environmental Lead Poisoning in Children. Journal of Health and Pollution, 1( 2), 14-23, November 2011 web. 1 Dec 2015 < http://journalhealthpollution.org/doi/full/10.5696/2156-96188.8.131.52>
Flora, Gagan, Gupta,Deepesh and Tiwari, Archana. Toxicity of Lead: A Review with Recent Updates. Interdisciplinary Toxicology,5(2), 47-58,June 2012 web. 1 Dec. 2015 < http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3485653/>
Hernberge, Sven. Lead Poisoning in a Historical Perspective. American Journal of Industrial Medicine, 38, 244-254. 20 February 2000 web. 1 Dec. 2015<http://rachel.org/files/document/Lead_Poisoning_in_Historical_Perspective.pdf>
Kennedy, Chinaro, Lordo, Robert, Marissa, Sucosky, Boehm, Rona and Brown, Mary. Primary Prevention of Lead Poisoning in Children: A Cross-Sectional Study to Evaluate State Specific Lead-Based Paint Risk Reduction Laws in Preventing Lead Poisoning in Children. Environmental Health Journal, 13:93 7 Nov. 2014 web. 1 Dec. 2015< http://www.ehjournal.net/content/13/1/93>
Kinder, Carolyn. Lead Contamination in Our Environment. Yale-New Haven Teachers Institute. 5 July 1997 web. <http://www.yale.edu/ynhti/curriculum/units/1997/7/97.07.05.x.html>
Shaik, AP, Sultana, SA, Alsaeed, AH. Lead Exposure: A Summary of Global Studies and the Need for New Studies from Saudi Arabia. Hindawi Publishing Corporation, Vol.2014, 19 August 2014 web. 1 Dec. 2015 < http://www.hindawi.com/journals/dm/2014/415160/>
Tong, Shilu,Shirnding, Yasmin and Prapamontol, Tippawan. Environmental Lead Exposure: A Public Health Problem of Global Dimensions. World Health Organization, 78(9), 1068-1076. 2000 web. 1 Dec. 2015<http://www.who.int/bulletin/archives/78(9)1068.pdf