|LEAD Action News vol 11 Number
3, June 2011, ISSN 1324-6011
Incorporating Lead Aware Times (ISSN 1440-4966) & Lead Advisory Service News (ISSN 1440-0561)
The journal of The LEAD (Lead Education and Abatement Design) Group Inc.
Editor: Anne Roberts
Lead poisoning in China
By Russell Ng and Hannah Beedham, Interns from Macquarie University
Part II - Lead in China: The extent of lead exposure in China. Lead risks associated with children in China. Potential sources of lead in China
The extent of lead exposure in China
The World Health Organization (WHO) estimated in 2002 that about 800,000 children were affected by lead exposure each year, and about 34% of Chinese children had blood lead levels that exceed the WHO limit. This is in comparison to less than 1% of children in the US that have levels above the WHO limit (Pure Living 2007). It is further estimated by the WHO that lead poisoning accounts for 0.6% of the global burden of disease (WHO 2010). (This is a gross underestimate, but the only estimate there is. (E.O’Brien 2011)
Release of heavy metals such as lead into the environment has increased abruptly since the late 1970s, along with the rapid industrial development and economic growth in China. In pursuit of economic growth, some local governments in China devote more energy to gross domestic product than to environmental protection, which goes on to affect populations of people (Ji et al 2011). In fact, in 2001 China's lead smelting capacity reached 1,200,000 tons - second only to the US - and lead production reached 1,170,000 tons (Ye and Wong 2006).
Over the past decade China has been tightening regulations over the use of lead. Leaded gasoline was prohibited in 1999, and lead standards for fertiliser and food were passed in 2002 and 2004 respectively. In 2007, China also signed an agreement with the United States to ban the use of lead paint in the manufacture of toys (in 2009, China generated nearly 90% of US toy imports) and to address other product safety issues (Lee and Chen 2008). Regulatory standards were also set for industries, such as one by the National Development and Reform Commission which set regulations to prevent lead smelting mills being built in cities or suburbs (Ji et al 2011).
However, even with these tightened regulations, implementation and enforcement lag behind. For example, even though leaded gasoline was banned in 1999 with the intention for it to be phased out in major cities through the early 2000s, as of 2008 it was still available, especially in the western provinces (Lee and Chen 2008). A 2009 audit of 541 companies in Jiahe revealed that 309 were illegally operating, or did not meet environmental protection standards. Furthermore, many factories discharge lead waste into rivers and the atmosphere, and rely on local governments turning a blind eye because due to the need for tax revenue generated from such factories . There are also ways in which polluters escape from environmental monitoring, such as by discharging pollutants during the intervals between inspections, or secretly at night (Ji et al 2011).
In June 2010, 51 children under the age of 16 in East China’s Jiangsu province (for a map of China showing provinces, click here) were found to have excessive levels of lead in their blood, with a 4 year old boy having a blood lead level of 36.4 µg/dL. The case is similar to a string of similar cases in 2009, in that a lead-acid battery factory was located less than 100 metres from the Hekou village. While the government paid for medical treatment, there was no offer of nutrition subsidisation, nor was there further compensation for the damage as a result of the lead poisoning incident (Qian and Wei 2010).
In 2011, authorities in Gaohe, in the eastern Anhui province of China, closed two battery plants they blamed for causing lead poisoning of people living in close proximity. Among those affected were children just a few months old, with one being found to have a blood level of 24.5 µg/dL, and displaying symptoms of lead poisoning, such as lack of appetite and fatigue. Furthermore, residents said that children who tested above 25µg/dL were sent to a children’s hospital for treatment, but those who were below were left with nothing more than 400 yuan ($60) and a box of apples and bananas by the local government. While the plant opposite from the complainants was shut down, another plant further away is still in production (Chan 2011). These incidents are but a few out of a myriad of lead poisoning cases since just 2009, where until now more than 4000 children have been affected by lead poisoning (Ji et al 2011). Figure 2 below summarises areas of major lead poisoning cases in China since 2009.
Lead risks associated with children in China
Blood lead concentration in children tends to increase up to the age of 6, as comparative studies have shown that with growing age, children become more independently active and participate in more outdoor activities, leading to increased chances of lead exposure. This is opposed to younger children, whose risk of exposure to lead is mostly family and feeding-related (Dai and Fan 2007).
Higher blood lead concentration in boys than girls also indicates that boys have a higher risk than that of girls of the same age group, and again the difference is more significant in the older age group than in the younger age group. The reason may be that boys are generally encouraged to be more physically active and adventurous, including outdoors, increasing their risk of exposure to lead in the environment (Dai and Fan 2007). Supporting this, a study by Zhang et al (2009) found that blood lead levels tended to increase with age and attributed it to children’s changing behaviour and their increasing exposure to lead. The study also suggests that lead exposure for children in China comes primarily from outdoor sources rather than from indoor ones.
Family factors related to blood concentration levels in children include occupation, education, income, and behaviour of their parents, with the occupation of parents of utmost importance. Studies have shown that lead dust in homes is closely related to the blood lead concentration, the volume of lead exposure, parents’ occupation and exposure times. In fact, a study showed that the blood lead concentration was increased in 38 of the 91 children whose parents were engaged in work involving contact with lead with 10 of them requiring treatment (Dai and Fan 2007). This can be referred to as 'take-home exposure', where workers wear their work clothes home or launder them with the family laundry or when they bring scrap or waste materials home from work (Shen et al 1996). Furthermore, the education of the parents is related to the blood lead concentration of their children, with parents who have a low education often knowing nothing about lead hazards or lead poisoning to guide their children in avoiding the risk factors (Dai and Fan 2007).
Environmental lead pollution is another factor that draws a lot of attention in relation to the incidence of lead poisoning in children. Shen et al (1996) point to studies performed prior to the prohibition of leaded gasoline in 1999, which indicated that children exposed to potential industrial sources of lead, whether it be through proximity of residence or school, had higher average blood lead levels than populations of children not exposed to industrial sources of lead. Other studies referred by Shen et al. (1996) showed that children with extremely high blood lead levels attended schools near heavily-used highways. These levels were significantly higher than control children who lived further away from traffic.
However, Zhang et al (2009) recognize that most studies performed to date focus merely on subjects living in highly polluted areas. A study by Zhang et al (2009) was performed to investigate the degree of lead exposure in children aged 0-6 years in 14 cities with a large metropolitan area and advanced industry and economy. Out of the 44,045 children aged 0-6 in the study, 8.46% were found to have blood lead levels greater than 10 µg/dL, 0.73% with levels greater than 20µg/dL, and 0.20% of the total children in the study with severe blood levels greater than 45µg/dL and requiring chelation therapy. While the blood lead levels of children in Zhang et al's (2009) study were lower than those reported in the Chinese media, they were still higher than those reported in developed countries.
The level of the building in which children live also has an effect on the incidence of lead poisoning, because the atmosphere closer to the ground contains more lead. In some cities, the lead concentration is about 0.18µg/m3, but the concentration at one metre above the ground is 13µg/m3. Findings have indicated that children living in the lower stories of buildings are exposed to more lead than those living in the higher stories (Dai and Fan 2007).
Another source of lead is paint from toys and stationery. Children playing with toys have more chances to take in the lead, as well as from habitually biting pencils (Dai and Fan 2007). Certain foods, such as popcorn and preserved eggs, may also cause lead poisoning. Old-fashioned popcorn machines are made from lead alloy, releasing lead to the popcorns and preserved eggs, if made conventionally, use lead oxide as a food additive (Dai and Fan 2007). Lead industries in the countryside can also cause contamination of fresh vegetables, fruit and rice. In fact, a study has shown that the lead content of rice grown near a smelter was 18 times greater than the content of lead in rice grown in non-polluted farmland (Shen et al 1996). Lead pollution may also exist in the production process of children's foods such as canned foods, canned vegetables, canned fruits, and canned juices, soft drinks and candies. Children eat such foods in an increasing volume, thus daily intake of lead is increased with their age (Dai and Fan 2007).
What potential sources of lead exist in China?
In China, lead compounds are regularly added to plastics and vinyl to make them more resistant to high temperatures; and, because lead is heavy, it is often added to cheap metal products as well as herbal products to mislead customers into thinking they are getting the amount by weight they are paying for. (Oster and Spencer 2006). Lead is also heavily prevalent from other sources, such as coal-burning, smelting factories, lead paint and e-waste recycling - some of which are the main source of economic income in some towns, especially in Southern China (Lee and Chen 2008).
China’s methods of recycling lead-acid batteries are very basic, and operate on a small-scale. Such facilities are responsible for producing approximately 50 percent of all the lead being emitted into the environment, particularly in waterways and soil (Go & Scull 2008). A countrywide lead-acid storage battery recycling network has not been established in China, unlike most Western countries, which have formed secure recycling systems and have developed strict regulations (Changhai & Zhang 2009). There has been a phenomenal increase in lead battery usage due to the increase in electrical bikes over the past 20 years; however, with this increase there has not been any adequate development on infrastructure for the disposal of the batteries. (Go & Scull 2008)
According to the China Battery Industry Association, there are over 1,400 battery manufacturers in China, which produced over 30.5 billion batteries in 2005, and 13.9 billion of these sold for use in China (Go & Scull 2008). The main source of lead-acid storage batteries recycling is individuals, who account for approximately 60% of all the lead-acid battery recycling. The final 40% is made up from battery retailers (18%), secondary lead smelters (9%), battery manufacturers (8%) and vehicle maintenance plants (5%) (Changhai & Zhang 2009). On average, China contributed to a third of the world’s battery output in 2001, with a consumption level of 10.7 batteries used by a person in China each year (Go & Scull 2008).
According to a report by Research and Markets produced in 2007, China’s lead-acid storage battery industry is growing at a rate of 30 % annually. This industry is driven by the increase in technologies in China, and their need for lead-acid batteries used increasingly, in particular, electronic -bikes (e-bikes). E-bikes have increased in popularity considerably fast in China, especially in urban locations (Go & Scull 2008). China’s significant usage of e-bikes is due to the fact that they are affordable, and do not require a driving licence (Bloomberg 2009). Over 10 million e-bikes were produced in 2005, which is approximately more than three times the amount of cars produced in the same year. This is significantly large in terms of the lead-acid storage batteries consumed, as currently, the bike batteries have a very limited life of only 1 to 2 years, but emit similar rates of lead into the environment during production and at end of life as car batteries, which have a longer life span.(Go & Scull 2008).
The China Electrical Equipment Industrial Association aimed to lower the lead battery demand in China by reassessing the vehicle standards of the e-bike, and reducing their output. To do this, regulations will be enforced limiting the speed and size of e-bikes, which may cause some manufacturing companies to cease production. According to Barclays Capital, the e-bike market is responsible for more than 20% of China’s lead consumption (Bloomberg 2009). Currently, the limiting factor for the e-bikes is that they have a lead-acid battery, which is unsuitable for the growing demands of daily commuting, because the batteries are too heavy for the bike to easily handle (ebikes 2005). Improvements in these batteries are being undertaken; however, there will be a larger market for the e-bikes if lithium-ion batteries are to be used (Ramzy 2009).
When disposed of correctly, lead-acid storage batteries are sent to a licensed recycler, where the lead and plastic used are reclaimed, following strict environmental regulations, and then sent back to the battery manufacturers to produce a new battery. Most developed countries use advanced technologies to break down and separate spent lead-acid storage batteries. The materials are then treated and mixed with primary lead concentrate and then given to a smelting system (Changhai & Zhang 2009).
In China, a majority of the batteries are disposed as regular garbage, which can cause them to leak and contaminate soil, groundwater and surface water supplies; with a single battery contaminating approximately 12 cubic metres of water or one cubic metre of soil. Due to the lack of legislation regarding the recycling and correct disposal of e-waste, many workers in the recycling companies are at serious risk of lead poisoning from these improperly disposed lead-acid storage batteries (Go & Scull 2008). More traditional ways are still in place to dispose of the spent lead-acid batteries, with approximately 50% of secondary lead mills partaking in manual labour to break down and separate the lead-acid batteries. The resulting lead paste and mud is used in small reverberatory furnaces or blast furnaces. Other secondary lead mills use machines to break down the batteries; however, manual labour is still used for the separation of the materials. Only a few large-scale lead battery recyclers in China have advanced, fully automatic dismantling operations (Changhai & Zhang, 2009).
To address the issue of e-waste, China has introduced regulatory measures regarding lead. The Occupational Diseases Prevention and Control Act of 2002 reaffirmed the authority of the Ministry of Health to revise and develop new Occupational Exposure Limits (OELs). Regulations were also devised around fines for subjected violators (such as factory owners), revocation of business licenses, as well as criminal prosecution. These revised regulations did not have an effect on reducing lead exposure levels from smelters and battery factories when evaluated in 2006. In fact, the average exposure levels to both lead dust and fumes increased when compared to the OELs between the years 2003 and 2005, with some levels being even higher then before the implementation of the Occupational Diseases Prevention and Control Act of 2002 (Go & Skull, 2009). In 2003, The Oriental Golden Lead Co Ltd constructed a lead smelter near the village of Mafang, located in Henan province. However, it failed to do an environmental impact assessment on the site prior to construction. With the excessive emissions of lead dust, 259 children had their blood lead levels tested, and in 2005 almost 80% of the children had levels exceeding the acceptable level of 10ug/dl, with 8 children recording over 30 ug/dl (OKI 2008).
The lead poisoning rate among lead battery workers decreased from 45 % between the period of 1990-2002, to 36.8 % between 2003 and 2005. The 2002 Act had a very minimal impact on the occupational levels (Go & Scull 2008). There was an incident of lead poisoning from lead battery manufacturing and recycling in China during 2005 at Guangzou Nanfang Guangyuan Super Energy Battery Ltd, which is one of the major car battery producers in China. Staff started complaining of symptoms such as nausea and stomach pains, and, after physical examinations, 140 workers were diagnosed with lead poisoning. Following chelation treatment the workers were forced to return to work under the same conditions as the company had denied all claims of negligence, and stated that they had warned their workers when hiring them (OKI 2008).
A significant factor associated with e-waste in China is the lack of sufficient technology to dispose of lead-acid storage batteries. There are many cases in which the batteries are dumped in landfills, or left in warehouses due to the lack of proper disposal facilities (Go & Scull 2009). In Gansu Province, residents were determined to investigate if a local lead smelting plant was poisoning their families; however, the local medical facilities all refused to test their blood lead levels. They travelled to a different hospital, and 954 children were found to have blood lead levels exceeding 10ug/dL, as well as 43 adults with levels greater than 40 ug/dL. The Chinese media reported that the Huixian Country Non-Ferrous Metal Smelting Co Ltd had situated this smelting plant in a rural location, as it would be more likely to escape scrutiny of the government. This facility had produced 5,000 lead ingots, and had left waste in open slag piles (OKI 2008). Since 1998, urban centres such as Shanghai and Beijing introduced initiatives to increase awareness of recycling batteries, through placing recycling bins for batteries in popular public places such as shopping centres. These bins did not have a great impact on lead battery disposal, as they were located quite far from where people live, making them less convenient then putting the batteries in one’s own bin (Go & Scull 2008).
In 2001, the Shandong Association of Battery Pollution Prevention and Treatment set up a network for collection and maintenance of waste batteries for recycling purposes. The group also contributes funding towards research on environment -friendly batteries. Also in 2001, the University of Science and Technology, in Beijing, developed a “chemical disposal” technique, in which lead is purified before being discharged. This method has been trialed in a battery recycling plant located in the Hebei Province. During 2008, Beijing city built the world’s largest plastics recycling plant, and continued with its initiative of installing recycling bins around urban centres. China also committed to cooperate with the United States in working out a treatment and disposal regime for lead-acid storage batteries (Go & Scull 2008).
Lead in paint
Lead paint is any paint that relies on lead compounds for its colour: for example white lead (also known as lead carbonate) or vivid yellow lead chromate. The lead in these paints gives the paint its tint, and is highly opaque, meaning that a relatively small amount of the compound can cover a large area. Furthermore, leaded paint is highly water-resistant, as well as being able to neutralise acidic decomposition products of some oils that make up the paint, so the coating stays tough, yet flexible, and crack-resistant for longer (Crow 2007).
Regulatory levels of lead in paint have existed in China for many years. In 1986, Toy Safety prohibited lead concentrations of more than 2,500 ppm, and soluble lead more than 250ppm for paint coating in toys, pens, pencils, and children’s painting materials. This standard was updated in 2003 to prohibit paints with soluble lead concentrations of more than 90ppm. In 2001, the same standard of no more than 90ppm of lead in paint was applied to paints for indoor decorating and refurbishing materials (Lin et al. 2009). However, paint with higher levels of lead often sells for a third of the cost of paint with low levels. As a result of an intensely competitive and poorly regulated market, Chinese factory owners will attempt to increase profits by cutting corners and using cheaper leaded paint (Barboza 2007).
Although China prohibited production of leaded gasoline in 1999, it is still available, especially in the Western provinces (Lee and Chen 2008). Lead compounds are added to gasoline to increase the octane and enhance performance. However, when leaded gasoline is used, particles of lead are emitted into the atmosphere, where they can persist for a few weeks before settling onto the ground. Prior to 1999, China used leaded gasoline extensively, with a lead content up to 0.78 g/L (Shen et al 1996). Undoubtedly vehicles that ran on leaded gasoline would have contributed greatly to atmospheric lead pollution as leaded gasoline accounted for 80-90% of airborne lead pollution in large cities where it was used (Meyer et al 2008).
A study that was a part of the International Tobacco Control project compared the content of Chinese cigarettes with those from other countries; all 13 Chinese cigarette brands tested were found to have significantly elevated levels of heavy metals, including lead. Some, in fact, contained up to 3 times the level of lead compared to other cigarette brands, constituting a potential global public health problem, as exports of Chinese cigarettes continue to increase (McEwen 2010).
A study performed by the University of Michigan showed that candles produced in China released high levels of lead into the air during burning. Candles that had high lead emission levels when burnt contained metal cores made of either pure lead or lead alloy. Metal cores are used to provide rigidity to the wick, to provide an even and slower burn rate, ideal for scented and ceremonial candles (Reyes 1999).
The US Consumer Product Safety Commission (CPSC) has determined that candles using lead wick could present a lead poisoning hazard to young children. Emitted lead presents a risk to children from exposure by way of inhalation and via ingestion of lead that may settle on surfaces in the room, which could remain accessible to a child for an extended period of time (HKTDC 2001).
Countries such as Australia and the US have taken action in banning the importation and manufacturing of candles with lead-wicks; however, at this moment, it is not clear as to whether China even recognises the risk of lead exposure as a result of burning candles with lead-wicks, let alone has policies put in place that pertain to the problem.
A study by Al-Saleh et al. (2009) tested a series of lipsticks for lead. While the primary ingredients found in lipstick are wax, oil, alcohol and dye, lead can be present as impurities in the colour additives. The study found that some brands of lipstick made in China contained lead around or above 20 PPM; the FDA limit for lead as impurities in colour additives used in cosmetics with the highest lead content was found in shimmering coloured lipsticks, which may come from Mica, a group of silicate minerals that are widely used in the cosmetics industry.
Chinese-made eye shadow has also been examined as a lead risk. The study by Al-Saleh et al. (2009) also looked at eight different brands of pressed powder eye shadow, and found that one brand had lead contents above 20 ppm. Similarly, another study by Omolaoye et al (2010) managed to find that seven out of their test of twenty eye shadows contained lead contents higher than 20µgg-1 (unable to confirm if this measurement is the same as FDA's limit of 20 ppm).
Preserved eggs, also known as pi dan, are a traditional Chinese food which is made from egg with some additives, one of which is lead oxide. Shen et al (1996) found that five out of the eleven tested brands of preserved eggs contained lead concentrations greater than 3µg/g, which was at the time the allowable lead level for food in China, with the highest one as high as 10.3µg/g. More recently, the Consumer Council (2006) tested 19 samples of preserved eggs taken from both retail outlets and restaurants, and found seven of the samples to contain lead. However, it was reported that these levels were well below the permitted amount stipulated in the Food Adulteration (Metallic Contamination) Regulation of 6 mg/kg (or 6µg/g). (*Authors’ Note: unable to verify these permitted levels of lead in food for both time periods of 1996 and 2006, nor could we explain how the permitted levels had in fact risen from 3 µg/g to 6 µg/g)
Bao mi hua, one of the most favourite foods among Chinese children, similar to popcorn in Australia, also potentially contains considerable amounts of lead. Bao mi hua is processed in a special tank alloyed by iron and lead under very high temperature; as a result some of the lead is melted onto the food. A study that looked at the lead content of 66 samples discovered that the highest content of lead was as high as 21µg/g (Shen et al 1996)
Traditional medicines such as hai ge fen have also been proven to contain substantial quantities of lead, with several cases of lead poisoning due to Chinese traditional medicines. Unfortunately, there has been little or no comprehensive data available on this potentially large lead risk (Shen et al 1996)
Sewage sludge as fertilizer is widely used in China because of its rich source of nutrients for crop production; however, precautionary steps must be taken to address the risks of heavy metal accumulation due to the application of large volume of sewage sludge fertilizer. (PCARRD 2006). For more information on the issue we refer readers to The LEAD Group’s LEAD Action News article title, “Biosolids used as fertilizer in China and other countries”
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Updated 25 January 2012