**2.3. Causes of air and soil pollution from lead**

it has been reported that lead may leak from WEEE and battery waste by the effect of acid rain. In 2000, the EU developed the "Directive of End-of-Life Vehicle (ELV)" to solve the problem of waste. The directive necessitated the recycling of end-of-life vehicles, and the ratio of lead recycling to collecting lead-acid batteries was improved. A similar recycling system has been constructed in Japan, and lead-acid battery recycling is additionally mandated by law.

**Figure 1.** Lead use and lead production. A. The amount of lead used in various products in 1996 and 2009 in Japan. B.

29 A. The amount of lead used in various products in 1996 and 2009 in Japan. B. Worldwide lead production in

32 **2.2. Emission Control of Lead in Japan and Other Countries** 

The use of lead in 1996 and 2009 in Japan is depicted in Figure 1A [8]. More than 80 % of lead is utilized for the production of lead-acid batteries for cars and industries. The second most common use is in inorganic chemicals, such as a polyvinyl chloride stabilizer, crystal glass, and paint. A polyvinyl chloride stabilizer containing lead was widely used due to its protective effects in the elimination reaction of vinyl chloride by oxygen. Crystal glass, which contains a high concentration of lead(II) oxide (PbO), is also widely used due to its high degree of transparency and refractive index, similar to crystal. Other common uses for lead include solder for electronic materials, tubes for draining and exhausting, and plates for medical equipment and lagging materials of underground cable. Moreover, lead production is rapidly increasing in some countries due to an increase in the production of lead-

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10 acid batteries, especially in China (Fig. 1B) [9].

250 Advances in Bioremediation of Wastewater and Polluted Soil

A

28 **Figure 1.** Lead use and lead production.

Worldwide lead production in leading countries.

B

30 leading countries.

31

The EU also issued a strict directive in 2003 on the restrictive use of certain hazardous substances in electrical and electronic equipment (referred to as the "Restriction of Hazardous Substances (RoHS) Directive"). The directive forbids the use of hazardous heavy metals (e.g., Pb, Hg, Cd, and Cr(VI)) in newly produced products of electrical and electric equipment. The United States also issued a similar law, the "Electric Waste Recycling Act of 2003." In compli‐ ance with these directives, lead-free products (solder, glass, and paint) have been developed, and the use of lead-free solder and lead-free paint is now the standard practice in Japan.

Heavy metal pollution has become an increasing concern in the EU [10]. The amount of waste of electrical and electronic equipment (WEEE) in 2005 was approximately 9 million tons and is steadily increasing at a rate of 5 % annually. The wastes are generally burned or buried without any treatment. If the total amount is calculated based on the assumption that WEEE contains approximately 5 % solder, 22,500 tons of lead is lost as waste every year. In addition, it has been reported that lead may

Another factor related to lead consumption is polyvinyl chloride consumption. In 2012, global polyvinyl chloride consumption was approximately 36 million tons. Polyvinyl chloride contains approximately 4, 500 ppm of lead stabilizer; thus, 162, 000 tons of lead stabilizer was exhausted as burned ash. The EU issued a strict directive on the management of packaging waste (Directive 94/62/EC), which banned the use of lead stabilizers in vinyl chloride produc‐ tion. To reach the target value of this directive, lead-free stabilizers, such as those containing Ca and Zn, have been developed. Furthermore, old pipes and electrical codes made of polyvinyl chloride are gradually being changed to lead-free ones in homes and industries.

Due to the efforts to decrease lead emissions, air and soil pollution from lead has decreased. According to an investigation from the 1980s to 2000s on lead concentrations in the air and blood by Thomas et al. [11], the lead concentrations decreased after the ban on lead gasoline. Recently, the blood lead levels (BLLs) of inhabitants and the concentrations of lead in the air and soil in urban and agricultural areas have been investigated. The results suggest that the lead concentrations did not exceed nonpoisonous levels, even in the countries in which lead is produced [12, 13].

In the industrial areas where mining and metallurgy occurred, however, a significant amount of unusable lead was discarded in the soil, and effluent from the factories had been directly exhausted to the rivers without any posttreatment removal of heavy metals. In Uruguay, for example, drinking water and the soil are critically polluted by metallurgy industrial wastes because most of the hazardous wastes are dumped in the rivers [7]. Moreover, lead gasoline is still utilized in Uruguay, and many old cubes of tap water are made of lead. The BLLs in many Uruguayans are much higher than in other countries [14]. In mining areas (e.g., Paraná state) in Brazil, 177, 000 tons of waste from metallurgy and mining has remained in the soil for more than 60 years [15]. When lead concentrations in 171 soil portions were analyzed, extremely high concentrations (10, 000–52, 000 mg/kg) of lead were found in the soil near a metallurgy factory. Moreover, the inhabitants near a mining company in the Czech Republic had an average BLL of 37.2 μg/dL, and 40 % of the lead workers in the southwest of Nigeria had an average BLL of 60 μg/dL [16, 17]. Additionally, the soil near a car battery processing workshop in Kerman City, Iran, was found to contain 5, 780 mg/kg of lead [18]. The BLL of Indians near a residential area was 20–25 μg/dL, and the lead concentration of PM10 (or PM2.5) in the residential area was very high (10–14 mg/m3 ) [11, 19].

Soil pollution from lead was not observed in the major cities in China, such as Beijing and Hong Kong; therefore, the BLLs of inhabitants in these cities were normal (4–5 μg/dL) [20-22]. The number of mining and metallurgy factories is rapidly increasing in China due to the increased consumption of lead-acid batteries. However, no formal reports on the lead con‐ centration and BLL have been reported in areas predominantly inhabited by mining and metallurgy factories, such as Zhejiang and Guangdong provinces. According to the WEB report [4], it is suspected that 100, 000 children are suffering due to lead toxicity. Therefore, in China, the areas predominantly inhabited by mining and/or metallurgy industries are thought to contain extremely high lead concentrations which are exhausted into the air, river, and soil.

Another potential cause of soil pollution from lead is a firing range. One of the worst cases of soil pollution from lead at a firing range demonstrated more than 10 kg/kg of lead due to remnant lead alloy bullets. Therefore, lead pollution in firing ranges may be as harmful as in mining areas.

#### **2.4. Effects of lead pollution on the health of inhabitants living near metallurgy and mining areas**

The BLL is an indicator of pollution from lead. Lead decreases the IQ value when the BLL is greater than 20 μg/dL [23]. A test to measure the ability of recognition in monkeys suggested that dysgnosia was observed in monkeys with BLLs of 10–13 μg/dL. Moreover, lead toxicity was observed when the BLL exceeded 40 μg/dL. According to recent studies, the BLL should be maintained below 10 μg/dL [24, 25].

The main route of exposure for an elevated BLL is ingestion. The amount of lead that adult subjects ingest from food is generally 20–25 μg/kg and 5–10 % is absorbed. Approximately 100 mg of lead is present in the body. The sensitivity of lead in a child is much higher than in an adult because 40 % of the ingested lead is absorbed. A previous report demonstrated that when more than 5 μg/kg/day of lead was ingested in infants, 32 % of the lead was absorbed, although no accumulation was observed in infants who ingested less than 4 μg/kg/day. The WHO also suggested that the BLL was not increased in those who ingested less than 4 μg/kg/day [26].

The other most common route of exposure is polluted air. Approximately 40–50 % of lead taken in from the nose is absorbed by the lung. The relationship between the concentration of lead in the air and the BLL is shown in Figure 3 (based on the data from the study by Thomas et al. on pollution from lead gasoline [11]). The BLL was found to be strongly correlated with air pollution.

Safety standards are defined to keep the environment safe. In Japan, the lead concentrations in the air and wastewater are below 1 ng/m3 and 0.01 mg/L, respectively. Moreover, the normal BLL observed in Japanese is 1–3 μg/dL, and the normal concentration of lead in the soil is 15– 30 mg/g. The lead concentrations in the areas near mining and metallurgy industries listed in Section 2.3 are greater than 1, 000 mg/kg, which are unusually high and dangerous. Therefore, to maintain a safe environment for those living near these areas, an effort to decrease lead emissions and remediation in these areas must be rapidly implemented.

**Figure 3.** Effect of lead concentration in the air on the BLL. The figure was prepared based on the data from the study by Thomas et al. [11].
