What heavy metals are, how they harm a body, and overseas cases from 1956, around 1912, and 2014

Representative heavy metals named in the essay include cadmium, lead, chromium, zinc, mercury, arsenic, iron, manganese, and copper. They generally exist as oxides and compounds, occur in trace amounts in nature, and can accumulate excessively through industrial activity. Even at low concentrations they show toxicity, are hard to break down biologically, and biomagnify up the food chain. Most tend to accumulate in the body for a long time, are not easily excreted, and become a threat by binding with body proteins. High density, ductility, and conductivity are why they are widely used in industry and, at the same time, become a cause of pollution. Natural sources include volcanic activity, weathering, wildfire, and marine eruptions; artificial sources include mining, smelting, thermal power, and agricultural insecticides; other sources include electronic waste, urban sewage, and medical waste. Cadmium, atomic number 48, is a bluish silver-white metal, highly toxic; in acute poisoning, difficulty breathing, tightness in the chest, and cardiopulmonary insufficiency can occur. Lead, atomic number 82, is bluish-white when freshly cut and gray in air, and is a metal people have used the longest; most poisoning is chronic, beginning with loss of appetite, then pain, headache, and vomiting, and it also affects the nervous system. Copper, atomic number 29, is reddish-brown as a metal and blue as a compound; in acute poisoning, vomiting, vomiting of blood, and high blood pressure can occur, and in chronic poisoning the liver and kidneys are damaged. In soil they hinder plant growth and can enter the body through crops; in water they accumulate in aquatic life and can become a drinking source; in air they enter through the respiratory tract, travel long distances, and can also be a cause of acid rain. Mercury is placed with nervous damage, cognitive impairment, and fetal malformation; lead with impaired brain development, anemia, and reduced kidney function; cadmium with kidney damage, osteoporosis, and reduced lung function; arsenic with skin lesions, cancer, and increased cardiovascular risk; chromium with respiratory irritation, dermatitis, and increased risk of lung cancer. They enter mainly through the respiratory tract, the digestive tract, and the skin, spread through the blood, and accumulate in the liver, the kidneys, and the bones. Acute poisoning occurs with a large amount in a short period and can lead to death; chronic poisoning advances slowly, early symptoms are not distinct, and over time it can cause nervous damage, reduced kidney function, and cancer.

Accidents related to heavy-metal poisoning became an occasion, in the course of industrialization, for waking to the importance of environmental management, and led to stronger policy and regulation, but pollution continues, centered on developing countries, and international cooperation is still needed. Minamata disease, first reported in 1956 in Minamata, Kumamoto Prefecture, occurred when Shin-Nippon Chisso — now JNC — discharged wastewater containing methylmercury into Minamata Bay; residents who ate contaminated fish and shellfish suffered abnormalities of the central nervous system. Afterward Japan enacted a water-pollution prevention law, strictly regulating chemical-waste treatment at factories, removed contaminated sediment from the bay, and controlled fishing in the contaminated area. Through 2001, 2,265 patients were officially confirmed, and 1,784 of them were reported to have died; Itai-itai disease, in the Jinzu River basin of Toyama Prefecture from around the 1910s — Also, the onset from around 1912 — occurred when cadmium in waste ore from Mitsui Mining’s Kamioka mine polluted the river, and residents who used it as drinking and agricultural water were poisoned; it is osteomalacia from cadmium pollution. Afterward Japan strictly regulated cadmium discharge, purified contaminated soil and water, limited farm produce from the area, and strengthened health monitoring. An exact death toll is not clear, though many patients are known to have died from extreme pain and complications. In 2014, Flint, Michigan, changed its water source from Lake Huron to the Flint River to cut costs; the river water was highly corrosive, lead leached from old pipes into tap water, and residents were poisoned. Afterward the city returned to Lake Huron, replaced lead pipes, and federal and state governments strengthened water-management standards and monitoring. A direct death toll from lead poisoning is not clear, though deaths related to a worsening of health were reported; at least twelve people are known to have died from an outbreak of Legionnaires’ disease from the contaminated water.

Korean cases as 2024 accounts place them, and responses the essay names

A 22 April 2024 account, on Earth Day, places an 1,853rd death among humidifier-disinfectant victims, and a press conference in front of the Yeouido headquarters of Oxy, in Yeongdeungpo, Seoul, by victims, the Environmental Health Civic Center, the Seoul Environmental Movement Union, and the Korean Federation for Environmental Movement, urging Oxy Reckitt Benckiser and Aekyung to carry out compensation. Kim Bok-hui, a victim who had lived in Cheonan, died on the 6th, as that account places the day, at Dankook University Hospital in Cheonan, without having received proper compensation in life. She had used Oxy and Aekyung products, developed asthma and chronic obstructive pulmonary disease, reported the harm in 2013, and was recognized under the humidifier-disinfectant victim relief law; she had gone between hospital and home for eleven years with severe asthma. The 2017 relief law allows hospital and care costs, but victims and families have continued to ask firms for proper compensation. In April 2022 a mediation committee presented a final proposal that Oxy and nine firms pay up to about 924 billion won to some 7,000 victims, but Oxy and Aekyung, whose shares were large, opposed accepting it, and as of that April 2024 account it had not been carried out for more than two years. On 11 January, as the same account places the date, a court recognized the guilt of former representatives of SK Chemicals and Aekyung, in effect recognizing a causal link between all humidifier-disinfectant raw materials and lung disease, but firms were still delaying contribution payments. A 4 September 2024 account places Gunsan Customs analyzing jewelry sold on AliExpress and Temu and detecting cadmium and lead over domestic safety standards. Of 172 items analyzed, about 15 percent, 26 items, were over the standard: lead from 1.1 times to a maximum of 3,812 times, and cadmium from 37 times to a maximum of 948 times. A Ministry of Environment notice, 2022-248, forbids mixtures with cadmium at 0.1 percent or more, or lead over 0.009 percent, for use as metal jewelry. Cadmium and lead are substances the International Agency for Research on Cancer has designated as possibly carcinogenic to humans. Customs immediately held the 26 items and said it would strengthen supervision.

A 12 October 2024 account, drawing on an indictment that National Assembly Environment and Labor Committee member Kim Ju-yeong received through the Ministry of Justice, places Yeongpung’s Seokpo smelter. From 2015 through 2021, cadmium was deliberately discharged into the Nakdong River 1,064 times; contaminated groundwater reached 27.70 million liters, and cadmium contamination a maximum of 3,300 milligrams per liter, 165,000 times a standard of 0.02 milligrams, a fact caught in 2022 by the Ministry of Environment’s Daegu Regional Environmental Office. In December 2023, on the second floor of the plant in Bonghwa, North Gyeongsang, four subcontracted workers were exposed to arsine gas during work; one man in his sixties died and three were injured. Similar accidents had occurred twice before, but measures were not properly taken: arsenic meters were not properly managed, workers were not told of the danger, and respiratory protection was not provided. Park Yeong-min, the Seokpo representative, was sent to trial in custody on the 23rd of the previous month, as that October 2024 account places the day; Bae Sang-yun, the plant manager, was also detained and indicted for violations of the Occupational Safety and Health Act. In February two years earlier, as the same account places it, an acute arsine-poisoning accident had already occurred; the company then prepared a control plan, installed four arsenic meters, and provided that entry would be controlled if a meter exceeded 0.005 parts per million or a worker was not wearing a gas mask, with a monthly inspection by the safety team — yet the meters were not properly managed, and workers were working with a hole about 40 centimeters in diameter in the upper part of a tank. An earlier arrest warrant for the representative over cadmium discharge was dismissed on 15 November 2021. Responses named in the essay include chemical precipitation, ion exchange, membrane filtration with a nano filter, electrolysis, soil washing, an electrokinetic method, solidification and stabilization, phytoremediation, microbial remediation, mushroom remediation, biosorption, dust collection with bag filters and electrostatic precipitators, and adsorption with activated carbon. Processes in which excess absorption from lead exposure cannot be ruled out include lead-mine work, soldering, automobile repair, and ceramics that use red lead as a glaze. The same Korean report, at fuller length, is on CampusDown.

Sources

1. Representative heavy metals include cadmium, lead, chromium, copper, zinc, mercury, arsenic, iron, manganese, and copper. They generally exist as oxides and compounds. In a natural state they exist in trace amounts, but through industrial activity they can accumulate excessively in the environment. General characteristics of heavy metals: they show toxicity even at low concentrations, and biological breakdown is difficult. They have the trait of biomagnifying through the food chain, and so bring a greater risk to higher predators. Most heavy metals have a tendency to accumulate inside the human body for a long period. Once accumulated in the body they are not easily excreted, and become a threat by binding with body proteins. Heavy metals show high density. They are outstanding in ductility, malleability, and thermal and electrical conductivity. Most exist in a solid state. They have luster and can be forged. According to their physical characteristics they are widely used in industry, and at the same time become a cause of environmental pollution. Heavy metals have various oxidation states. Most exist in the form of cations and bind easily with other substances. Binding with body proteins, they destroy tissue cells or thin the bones, and remain without breaking down for a long period. Natural sources of occurrence include volcanic activity, weathering, wildfire, marine eruptions, and the like. Artificial sources include mining, smelting, thermal power generation, agricultural insecticides, and the like. Other sources include electronic-product waste, urban sewage, medical waste, and the like. Heavy metals are released into the environment by both natural processes and human activity. Natural sources arise from the earth’s geological processes, and artificial sources are mainly related to industrial activity. Understanding both types of source is important for effective heavy-metal management and for reducing pollution. Cadmium, atomic number 48, is a bluish silver-white metal, soft in strength, with good ductility and malleability, and very high in toxicity; in acute poisoning, difficulty breathing, a feeling of tightness in the chest, cardiopulmonary insufficiency, and the like occur. Lead, atomic number 82, is bluish-white when freshly cut and gray when exposed to air, and is a representative metal that humankind has used the longest; most poisoning is chronic, and after loss of appetite and the like appear in the early stage, pain, headache, vomiting, and the like appear, and it also affects the nervous system. Copper, atomic number 29, is reddish-brown in the metallic state and blue in the compound state; the method of extracting the ore is simple and working is easy; in acute poisoning, vomiting, vomiting of blood, high blood pressure, and the like, and in chronic poisoning the liver and the kidneys are damaged. A national research-and-development report, “The development of technology for risk reduction of harmful heavy metals (Lead, Cadmium,” is named as a source; the title is left as the extract places it. Heavy-metal pollution in the environment includes soil pollution, water pollution, and air pollution. Accumulating in soil, they hinder plant growth, destroy the soil ecosystem, and there is a possibility of entry into the human body through crops. Accumulating in aquatic life, they disturb the ecosystem; contaminated water becomes a drinking-water source and is a direct threat to human health. Heavy-metal particles exist in the air, enter the human body directly through the respiratory tract, can travel long distances and so affect a wide area, and can also be a cause of acid rain. Effects on animals include harm to the nervous system, the reproductive system, and the like, immediate death from acute poisoning, and, from chronic poisoning, a decline in the reproduction rate and a shortening of life. Effects on plants include hindering plant growth, interfering with photosynthesis, suppressing root development, destroying chlorophyll, and the like, and harm across the plant ecosystem. A decline or extinction of particular species from heavy-metal pollution disturbs the food chain of the ecosystem, destroys the balance of the ecosystem, and threatens biodiversity. There is a biomagnification phenomenon in which the concentration of heavy metals becomes higher toward higher predators, and the effect of heavy-metal pollution widens across the ecosystem. Mercury: nervous-system damage, cognitive impairment, and the causing of fetal malformation. Lead: hindering of brain development, anemia, and a decline in kidney function. Cadmium: kidney damage, osteoporosis, and a decline in lung function. Arsenic: skin lesions, the causing of cancer, and an increased risk of cardiovascular disease. Chromium: respiratory irritation, dermatitis, and an increased risk of lung cancer. Heavy metals enter the human body mainly through the respiratory tract, the digestive tract, and the skin. Fine dust in the air, intake of contaminated drinking water or food, contact with soil, and the like are the main paths. Heavy metals that have entered the body spread through the whole body through the blood, and accumulate in particular organs such as the liver, the kidneys, and the bones. In this process they bind with proteins, remain in the body for a long period, and show toxicity. Acute poisoning occurs when one is exposed to a large amount of heavy metal in a short period. Together with gastrointestinal symptoms such as vomiting, abdominal pain, and diarrhea, nervous abnormality, difficulty breathing, and the like occur, and in serious cases it can reach death. Chronic poisoning occurs when one is continuously exposed to a small amount of heavy metal over a long period. It advances slowly, and in the early stage symptoms are not distinct, but as time passes it can cause serious health problems such as nervous-system damage, a decline in kidney function, and the occurrence of cancer. Heavy-metal accidents have a serious adverse effect not only on environmental pollution but also on the health of the human body. Accidents related to heavy-metal poisoning became an occasion for waking, in the course of industrialization, to the importance of environmental management, and led to a strengthening of environmental policy and regulation in each country. But the problem of heavy-metal pollution still continues, centered on developing countries, and international cooperation and the arranging of countermeasures are needed. Minamata disease, first reported in 1956 in Minamata, Kumamoto Prefecture, Japan, occurred when Shin-Nippon Chisso — now JNC — discharged wastewater containing methylmercury into Minamata Bay. As a result, residents who ate contaminated fish and shellfish suffered abnormalities of the central nervous system from methylmercury poisoning. After the incident, the Japanese government enacted a water-pollution prevention law and strictly regulated the treatment of chemical waste at factories. It also carried out environmental restoration work such as removing contaminated sediment from Minamata Bay and controlling fishing in the contaminated area. Number of deaths: through 2001, 2,265 patients were officially confirmed, and of them 1,784 were reported to have died. Itai-itai disease, which occurred in the Jinzu River basin of Toyama Prefecture, Japan, in the 1910s — Also, the onset from around 1912 — occurred when cadmium contained in waste ore discharged from Mitsui Mining’s Kamioka mine polluted the river, and residents who used it as drinking water and agricultural water were poisoned with cadmium; it is osteomalacia from cadmium pollution. After the incident, the Japanese government strictly regulated cadmium discharge and carried out work to purify contaminated soil and water quality. It also limited the production of farm produce in the contaminated area and strengthened monitoring of residents’ health. Number of deaths: an exact number of deaths is not clear, but many patients are known to have died from extreme pain and complications. Cause of the Flint lead-poisoning incident: in 2014 the city of Flint, Michigan, in the United States, changed its water source from Lake Huron to the Flint River in order to cut costs. But the water of the Flint River was strongly corrosive, and lead leached from old lead pipes and became mixed into the tap water. As a result a state of affairs occurred in which residents were poisoned with lead. After the incident, the city of Flint came to use Lake Huron again as its water source, and proceeded with work to replace lead pipes. Also, the U.S. federal government and the state government arranged recurrence-prevention measures such as strengthening water-quality management standards and strengthening monitoring of lead pollution. Number of deaths: a direct number of deaths from the Flint lead-poisoning incident is not clear, but death cases related to a worsening of health from lead poisoning were reported. Also, from an outbreak of Legionnaires’ disease from the contaminated water, at least twelve people are known to have died. “Another humidifier-disinfectant victim has died… the 1,853rd death,” Monday 22 April 2024. Humidifier-disinfectant victims and environmental groups, saying that on the 22nd, Earth Day, an 1,853rd humidifier-disinfectant death had occurred, urged Oxy — Oxy Reckitt Benckiser — and Aekyung to carry out compensation and indemnity for victims. Victims, the Environmental Health Civic Center, the Seoul Environmental Movement Union, the Korean Federation for Environmental Movement, and others held a press conference that morning in front of the Oxy headquarters in Yeouido, Yeongdeungpo-gu, Seoul, and informed that “Kim Bok-hui, a humidifier-disinfectant victim who had lived in Cheonan, died on the 6th,” and stressed that Kim had not received proper compensation in life. According to the victims, Kim used humidifier-disinfectant products of Oxy and Aekyung, developed asthma and chronic obstructive pulmonary disease, reported the harm in 2013, and was then recognized as harmed under the humidifier-disinfectant victim relief law. For eleven years she went between hospital and home with severe asthma, and on the 6th she died at Dankook University Hospital in Cheonan, as that 22 April 2024 account places the day. Under the humidifier-disinfectant victim relief law put into effect in 2017, hospital costs and care costs can be received, but victims and surviving families have continued to demand proper compensation for harm from the firms. In April 2022 the mediation committee for humidifier-disinfectant victim relief presented a final mediation proposal that Oxy and nine firms pay compensation of up to about 924 billion won to some 7,000 victims, but Oxy and Aekyung, whose shares were large, opposed accepting the proposal, and as of that April 2024 account it had not been carried out for more than two years. On 11 January, as that account places the date, a court judgment came that recognized the guilt of former representatives of SK Chemicals and Aekyung, indicted on charges of having sold harmful humidifier disinfectant. This had the meaning of in effect recognizing causality with lung disease for all humidifier-disinfectant raw materials, and of holding the responsibility of manufacturing and selling firms more strictly, but the firms were in a situation of putting off the payment of contributions from day to day. “Heavy metals over the standard detected in China-origin overseas-purchase jewelry,” Wednesday 4 September 2024. Gunsan Customs, as a result of component analysis of necklaces, earrings, rings, and the like, detected cadmium and lead; 26 items in which harmful heavy metals were detected in large amounts were immediately held from customs clearance, and management and supervision were to be strengthened. Amid a recent large increase in the volume of overseas direct purchases, heavy metals exceeding the standard by 3,812 times were detected in China-origin overseas-purchase necklaces, earrings, rings, and the like. According to Gunsan Customs on the 4th, as a result of component analysis of jewelry being sold on China overseas-purchase platforms — AliExpress and Temu — cadmium, lead, and the like exceeding domestic safety standards were detected in some products. This exceeding detection of heavy metals by Gunsan Customs reached 26 items, about 15 percent of the 172 items whose components were analyzed. In the case of these products in which heavy metals were detected, lead exceeding the domestic safety standard from 1.1 times to a maximum of 3,812 times, and cadmium exceeding it from 37 times to a maximum of 948 times, were detected. In the case of the Ministry of Environment’s designation of restricted and prohibited substances, notice 2022-248, mixtures containing cadmium at 0.1 percent or more, or lead exceeding 0.009 percent, are forbidden for use as metal jewelry. Cadmium and lead are “substances possibly carcinogenic to humans” designated by the International Agency for Research on Cancer. In the case of cadmium, poisoning can cause Itai-itai disease, which occurred in Japan, and diseases of the respiratory, kidney, and digestive systems and the like. Lead, when there is poisoning, causes diseases of the kidney system, the central nervous system, the digestive system, the reproductive system, and the like. Accordingly, Gunsan Customs immediately took a measure of holding from customs clearance the 26 items in which harmful heavy metals were detected in large amounts. Gunsan Customs stated that it had come to carry out this component analysis in order to protect domestic consumers from controversy over the safety of China-origin overseas-purchase products, and that it planned to strengthen further, going forward, management and supervision at customs in order to prevent the bringing-in of overseas-purchase goods that harm the health of the public. “A worker dies of arsenic poisoning, Yeongpung’s Seokpo smelter, with repeated large environmental accidents, ‘reaching a limit’?” Saturday 12 October 2024. The office of National Assembly member Kim Ju-yeong: even after an arsenic-poisoning accident two years earlier, recurrence prevention at Yeongpung’s Seokpo smelter was inadequate; there is a record of deliberate cadmium discharge into the Nakdong River 1,064 times from 2015 through 2021. It was revealed that Yeongpung’s Seokpo smelter, at which a subcontracted worker died of arsenic poisoning, had not properly taken measures even though similar accidents had occurred twice in the past, and that an acute-poisoning death of a worker had occurred again. The Seokpo smelter deliberately discharged cadmium into the Nakdong River 1,064 times from 2015 through 2021, and the fact that the quantity of contaminated groundwater reached 27.70 million liters, and that the degree of cadmium contamination reached a maximum of 3,300 milligrams per liter — 165,000 times a standard of 0.02 milligrams — was caught in 2022 by the Ministry of Environment’s Daegu Regional Environmental Office. Thereafter, at the end of the previous year as a later passage in the same vein places it, and in December 2023 as the dated account places it, at Yeongpung’s Seokpo smelter, where a subcontracted worker died of arsenic poisoning, it was found that measures had not been properly taken even though similar accidents had occurred twice in the past. Company officials including the plant manager did not properly manage arsenic meters, did not even inform workers of the danger of arsenic, and did not provide respiratory protective equipment such as gas masks. According to the “Yeongpung Seokpo smelter indictment” that National Assembly Environment and Labor Committee member Kim Ju-yeong received, submitted through the Ministry of Justice, on the 12th, an acute-poisoning death of a worker occurred again because measures were not properly taken even though similar accidents had occurred twice in the past. Saturday 12 October 2024: in December 2023, on the second floor of the Seokpo smelter plant in Bonghwa County, North Gyeongsang, four workers belonging to a subcontracted firm were exposed to arsenic — arsine — gas during work, and one man in his sixties died and three were injured. In this connection, Park Yeong-min, the representative of Yeongpung’s Seokpo smelter, was sent to trial in a state of detention on the 23rd of the previous month, as that account places the day. Bae Sang-yun, the Seokpo plant manager, was also detained and indicted on charges of violating the Occupational Safety and Health Act. Looking at the prosecution’s indictment facts, in February two years earlier, as that account places it, an acute arsenic-trihydride poisoning accident had also occurred to a smelter worker. At that time, when the arsenic-poisoning accident occurred, the company side prepared a “control plan for safety and health management of arsine-generating processes” in order to prevent recurrence of the accident, and installed four arsenic meters. The control plan contained the content that “if an arsenic meter exceeds the standard of 0.005 parts per million, or if a worker is not wearing a gas mask, entry to the plant is controlled.” It was also to have the safety-management team carry out a regular inspection once a month. The prosecution writes that “despite this, company officials including the plant manager did not properly manage the arsenic meters.” As a result, the workers met with the disaster while working in a state in which a hole about 40 centimeters in diameter had been opened in the upper part of a tank. Earlier, an arrest warrant for the Seokpo smelter representative had been requested because of cadmium discharge and the like, but it was dismissed on 15 November 2021. Recurrence-prevention measures after the incidents, as the essay gathers them, include, after Minamata, the enactment of a water-pollution prevention law, the removal of contaminated sediment, and the control of fishing; and methods named for treatment include a chemical precipitation method that converts heavy metals into insoluble compounds, an ion-exchange method that removes ions selectively, a membrane-filtration method that separates heavy metals with a nano filter, an electrolysis method that precipitates heavy metals with electricity, a soil-washing method that extracts heavy metals with chemicals, an electrokinetic method that moves heavy metals with electricity, solidification and stabilization that convert pollutants into an insoluble form, a phytoremediation method that absorbs heavy metals with plants, microbial remediation that breaks down heavy metals with bacteria, mushroom remediation that absorbs heavy metals with fungi, biosorption that adsorbs heavy metals on the surface of living organisms, dust-collection technology that uses bag filters and electrostatic precipitators, and an adsorption method that adsorbs heavy metals with activated carbon and the like. As processes in which the possibility of excess absorption from lead exposure cannot be ruled out, because lead is handled directly in the work process or there is lead inside the workplace, there are lead-mine miners, soldering work, automobile-repair work, ceramics that use red lead as a glaze for porcelain, and the like.

Last updated: 14 November 2026