论文部分内容阅读
On July 8， 2015， Democratic Party of Hong Kong released that the lead content in the tap water of some buildings of Kai Ching Estate， public housing in Kowloon， under the supervision of the Hong Kong Housing Authority exceeded the level of WHO. This could be ascribed to the lead containing in the accessories and soldering in the plumber links. After this， tap water from nearly 30 blocks， buildings， or schools were detected with excessive heavy metal content， which includes lead， nickel， cadmium， etc.
On July 13， Hong Kong Center for Health Protection announced that at the end of May， a 72-year-old man living in Kai Ching Estate developed an infectious disease， Legionnaires' disease with caused fever， headache， diarrhea， breath difficulty and other symptoms. The patient may breathe in the polluted water spots and fog from the artificial water producing system. Related germs were detected in the kitchen， sprinkler and bathroom.
This news caused huge panic among nearby residents. They snapped up the bottled water in the supermalls and registered in the hospital to test their blood. 3 out of the 23 kids under six year old who were found with excessive lead content in blood are diagnosed with developmental retardation， and 5 were slightly developmental retardation. Although it was not proved that the symptom was related with drinking water， the 3 kids confirmed with the disease came from Kai Ching Estate.
Hong Kong Housing Authority said they would systematically replace the problematic parts， and discuss whether to enlarge the testing sphere. Meantime， Hong Kong Special Administrative Region government set up a review committee on excessive lead content in drinking water to look for the reasons， reflect and assess the standards and supervision system of the existing drinking water in Hong Kong.
It’s not a single case
According to the data of WHO， around 748 million people lack the access of purified drinking water， and the drinking water source of 1.8 billion people are tainted by feces. Thousands of millions of people lack the access to soap and water for washing hands to prevent the disease transmission. Annually， two million people die of unsafe drinking water， and public and individual sanitation problems. Polluted sewage is more and more used in agriculture， which may cause severe public health risks.
As a matter of fact， with the economic development and improvement of people's livelihood， the sanitation problem of drinking water gained unprecedented attention， the technology of purification and disinfection made continuous progress， and the process received stricter supervision. But due to factors like environmental pollution， water source quality， chlorine treatment， tap water pipelines， halter conservation， drinking water poison incidents are just common occurrence. In May 2009， 7 people in Hyderabad， India died of diarrhea after drinking polluted drinking water， and over 200 people were hospitalized. The local citizens said， as early as August， 2008， they already complained to the authority about the stink and change in the color of the drinking water. The government said， the parallel paved drinking water and sewage pipeline built 40 years ago may be tainted. The worker at nearby leather factory may not separate sewage from water when cleaning untanned leather， which caused the sewage to leak into the drinking water pipeline.
In November 2014， in Tielong Wood Farm in Guangdong province， China， villagers had symptoms like vomiting and stomachaches. Meantime， at least 16 children were detected with excessive lead in their blood； among whom three were diagnosed with blood lead poisoning. Disease control and prevention department found that， there are excessive Escherichia coli in the drinking water supplied to the local people. Worse still， the waste air and water emission from a dozen of non-ferrous metal factory， cement plant and hazardous waste disposal factory distributed around the Wood Farm may cause environmental pollution and lead to poisoning.
In June 2015， a massive poisoning of drinking water accident occurred in Alagir， Nordossetien， Russia. At least 450 people were hospitalized， including children aging 2 to 12 years old. Many people were diagnosed with inflammation in digestive tract， which may be caused by enteric infectious disease virus in the drinking water. The pathogenicity of the virus was stronger than that found in 2014. The government made citizens to take vaccination to prevent them from catching disease.
In July， hundreds of citizens in Le locle， the famous clock city in Swiss， had diarrhea and the local government detected eschrichia coli in the drinking water and believed the cause is the infectious drinking water. Measures are taken to clean all the pipelines and reservoirs of the drinking water and supply bottled water to the citizens. Although 80% of the drinking water comes from the natural spring and underground water， nearly half of which can be directly taken without being processed. However， pollution like this occurred in its history. In 1998， 84% of citizens among 3，300 people in La Neuveville， Swiss were attached with gastro-enteritis， which are caused by a breakdown of a water pump and the waste water permeated into the ground water zone.
WHO standard met， but still a long way to go WHO lists microorganism， chemical， and radioactive nuclide as the main factors affecting the quality of drinking water in the Water Quality Code of Drinking Water.
The Code proposed， whether be direct drinking water， processed water which is going to enter the water supply system， or processed water already in the water supply system， none of the 100ml water sample should be detected with eschericia coli or thermotolerant coliform bacterial.
Besides， the following table quotes some of the criteria values of the chemicals in the drinking water which may affect health.
However， scientists from the University of Nebraska-Lincoln in America found that， the uranium in the aquifer watered ground which over two million people in California and Midwest in America dependent on are 179 times of the safe value， and 78% of the pollution comes from chemistry and biologic fertilizers， so there might be a concentration of uranium in crops. Meantime， the U.S. NGO Environment Workshop detected perfluoro caprylic acid and poisonous chemical substances which produce Teflon non-stick pan， in the drinking water， which supply 6.5 million people in 27 states in U.S. and may cause congenital dysplasia， cancer and heart disease.
Director of Endemic Fluorosis Research Institute， China's Center for Disease Control Gao Yanhui said， over 87 million people were affected by fluorosis of drinking water in China， which made China the worst hit country in the world. Besides， till the end of 2013， over two million people living in areas with excessive arsenic in drinking water， and 30 million people were affected by waterborne iodine excess goiter.
A research done by the International "Water Support" Organization among 950 water sources in 300 villages in India showed that， feces-borne coli-group density is astonishingly high. In Bangalore where drilling wells are used as common water sources， and 75% of the well water is contaminated with Escherichia coli. Fluoride， arsenic and nitric acid are the major chemical substances which pollute the water resources in India. Chairperson of an Indian NGO "Fluorosis Research And Village Development Foundation" said， the fluorine content in waters of several provinces in India exceeds 48 mg.， and reaches 32 mg. even in the capital city New Deli.
The fresh water reservoir of India with 16% of the world population only accounts for 4% of the total amount in the world， and 40% of the surface and underground water can not be drunk because of geological and terrain factors. The fresh water resource is extremely scarce in India. And with the industrialization process， many unpurified poisonous effluents and family sewage flew into the lakes and permeated to the underground water zone， making the situation even worse. There is virtually no tap water system in villages in India， and many villagers only have access to heavily polluted underground water； while the cities lack maintenance of water supply system， there are only several hours of tap water supplied. Wealthy families have large reservoir of bottled waters， while poor families have to rely on water pumps to extract underground water. "Water Support Organization" report said， there is no split-flow treatment to separate feces and drinking water in many regions in India， and the purification facilities are usually so expensive that some are even illegally sold. The local religion and custom do not favor people to use washroom and other sanitation facilities. And women and children can run into danger when using these facilities， which greatly affect the health of Indian people. Till now， 76 million Indians do not have access to safe water， 10 million people are exposed to danger of arsenic poisoning， and 37.7 million are bugged by the diseases caught by impure drinking water. Over 140，000 children under five years old were died of diarrheal， causing a 600 million USD economic loss. Hence， there is still a long way to go for the drinking water to reach the WHO standard in developed or developing countries.
Pollution source， prevention and control
Water Quality Code of Drinking Water said， pathogen latent in the surface water comes from the pollution brought by urban sewage， agricultural sewage， sewer facilities in public restrooms， contact with wildlife and livestock； while germs in underground water mainly comes from polluted and discarded wells， drinking pipeline， soil fertilization， concentrated feeding of livestock， etc. "Feces are the sources of virulent germs， virus， protozoa， worms"， and climate and environment provide the external condition for the growth of microorganism. The above cases of bacteria poisoning in drinking water show that， higher content of flora often take place in the hot and wet seasons which are good for propagation， which are caused by the permeation of life and excretion sewage into the water pipeline or sources of drinking water.
The chemical component source in the drinking water are the same with some harmful bacteria， which were caused by life and agricultural sewage， natural deposit， climate impact， industrial effluents， pesticide application， water treatment materials， water-soluble pesticide used for public sanitation， and blue-green algae resulting from lake eutrophication.
So the government should make investment to ensure the quality of the water source， improve the purification technologies of the drinking water， strictly supervise the transportation utilizing process and make a good work on water quality supervision and facilities maintenance.
The scandal in Hong Kong， on one hand， showed the concern of the folks and authorities on water quality detection， which has helped spotted and solved the problem in no time； on the other hand， also showed the loopholes of the construction unites and governments in construction and supervision. Technological Director of Licensed Water Affair Professional Society Qi Deming said， the Hong Kong Water Affairs Rules and Housing Construction Contract require water pipes to use non-toxic materials， and the lead solder is banned. Tin content in the solder which sealing the water pipelines should be 99%. However， some companies buy cheap tin pieces to make homemade soldering tin with only 90% of tin content to save cost. The other contents may be heaveymetal like lead， which can cause lead residue when workers fuse tin pieces and solder pipelines. Besides， the regulation in Hong Kong is weak， pipeline workers can be employed to repair or install pipelines only with a technician license， which adds the risks. Hence， the director of the Bid inviting team of Hong Kong Housing Authority Zhang Datang said， they will put soldering materials into the scope of inspection， add 4 heavy metal including lead into the materials to be monitored in checking and accepting newly built buildings. And it requires contractors to do on-site test to prove there is no lead in the soldering materials.
Individuals can also play a part to safeguard the quality of drinking water. Director of sanitation research center of Kaohsiung Medical College in Taiwan professor Hong Yuzhu suggested， it's better to boiled the water which are taken two minutes after the tap water is turned on to 100℃， then open the lid boil it for another three minutes. This can largely reduce cancerogen content and kill germs. When closing the tap water connected by rubber pipes， we should take out the rubber pipe from the water to avoid reverse siphonage where water effluent can reflux and drag up to pollute the water supply pipe. Families with impounding reservoir should cover iron lid on the water pool to guard against the feces of birds or rotten leaves to pollute the water. The water reservoir should be cleaned up at least every half year to avoid the growth of algae. Household water filter should also be replaced frequently to avoid the reproduction of germs.
On July 13， Hong Kong Center for Health Protection announced that at the end of May， a 72-year-old man living in Kai Ching Estate developed an infectious disease， Legionnaires' disease with caused fever， headache， diarrhea， breath difficulty and other symptoms. The patient may breathe in the polluted water spots and fog from the artificial water producing system. Related germs were detected in the kitchen， sprinkler and bathroom.
This news caused huge panic among nearby residents. They snapped up the bottled water in the supermalls and registered in the hospital to test their blood. 3 out of the 23 kids under six year old who were found with excessive lead content in blood are diagnosed with developmental retardation， and 5 were slightly developmental retardation. Although it was not proved that the symptom was related with drinking water， the 3 kids confirmed with the disease came from Kai Ching Estate.
Hong Kong Housing Authority said they would systematically replace the problematic parts， and discuss whether to enlarge the testing sphere. Meantime， Hong Kong Special Administrative Region government set up a review committee on excessive lead content in drinking water to look for the reasons， reflect and assess the standards and supervision system of the existing drinking water in Hong Kong.
It’s not a single case
According to the data of WHO， around 748 million people lack the access of purified drinking water， and the drinking water source of 1.8 billion people are tainted by feces. Thousands of millions of people lack the access to soap and water for washing hands to prevent the disease transmission. Annually， two million people die of unsafe drinking water， and public and individual sanitation problems. Polluted sewage is more and more used in agriculture， which may cause severe public health risks.
As a matter of fact， with the economic development and improvement of people's livelihood， the sanitation problem of drinking water gained unprecedented attention， the technology of purification and disinfection made continuous progress， and the process received stricter supervision. But due to factors like environmental pollution， water source quality， chlorine treatment， tap water pipelines， halter conservation， drinking water poison incidents are just common occurrence. In May 2009， 7 people in Hyderabad， India died of diarrhea after drinking polluted drinking water， and over 200 people were hospitalized. The local citizens said， as early as August， 2008， they already complained to the authority about the stink and change in the color of the drinking water. The government said， the parallel paved drinking water and sewage pipeline built 40 years ago may be tainted. The worker at nearby leather factory may not separate sewage from water when cleaning untanned leather， which caused the sewage to leak into the drinking water pipeline.
In November 2014， in Tielong Wood Farm in Guangdong province， China， villagers had symptoms like vomiting and stomachaches. Meantime， at least 16 children were detected with excessive lead in their blood； among whom three were diagnosed with blood lead poisoning. Disease control and prevention department found that， there are excessive Escherichia coli in the drinking water supplied to the local people. Worse still， the waste air and water emission from a dozen of non-ferrous metal factory， cement plant and hazardous waste disposal factory distributed around the Wood Farm may cause environmental pollution and lead to poisoning.
In June 2015， a massive poisoning of drinking water accident occurred in Alagir， Nordossetien， Russia. At least 450 people were hospitalized， including children aging 2 to 12 years old. Many people were diagnosed with inflammation in digestive tract， which may be caused by enteric infectious disease virus in the drinking water. The pathogenicity of the virus was stronger than that found in 2014. The government made citizens to take vaccination to prevent them from catching disease.
In July， hundreds of citizens in Le locle， the famous clock city in Swiss， had diarrhea and the local government detected eschrichia coli in the drinking water and believed the cause is the infectious drinking water. Measures are taken to clean all the pipelines and reservoirs of the drinking water and supply bottled water to the citizens. Although 80% of the drinking water comes from the natural spring and underground water， nearly half of which can be directly taken without being processed. However， pollution like this occurred in its history. In 1998， 84% of citizens among 3，300 people in La Neuveville， Swiss were attached with gastro-enteritis， which are caused by a breakdown of a water pump and the waste water permeated into the ground water zone.
WHO standard met， but still a long way to go WHO lists microorganism， chemical， and radioactive nuclide as the main factors affecting the quality of drinking water in the Water Quality Code of Drinking Water.
The Code proposed， whether be direct drinking water， processed water which is going to enter the water supply system， or processed water already in the water supply system， none of the 100ml water sample should be detected with eschericia coli or thermotolerant coliform bacterial.
Besides， the following table quotes some of the criteria values of the chemicals in the drinking water which may affect health.
However， scientists from the University of Nebraska-Lincoln in America found that， the uranium in the aquifer watered ground which over two million people in California and Midwest in America dependent on are 179 times of the safe value， and 78% of the pollution comes from chemistry and biologic fertilizers， so there might be a concentration of uranium in crops. Meantime， the U.S. NGO Environment Workshop detected perfluoro caprylic acid and poisonous chemical substances which produce Teflon non-stick pan， in the drinking water， which supply 6.5 million people in 27 states in U.S. and may cause congenital dysplasia， cancer and heart disease.
Director of Endemic Fluorosis Research Institute， China's Center for Disease Control Gao Yanhui said， over 87 million people were affected by fluorosis of drinking water in China， which made China the worst hit country in the world. Besides， till the end of 2013， over two million people living in areas with excessive arsenic in drinking water， and 30 million people were affected by waterborne iodine excess goiter.
A research done by the International "Water Support" Organization among 950 water sources in 300 villages in India showed that， feces-borne coli-group density is astonishingly high. In Bangalore where drilling wells are used as common water sources， and 75% of the well water is contaminated with Escherichia coli. Fluoride， arsenic and nitric acid are the major chemical substances which pollute the water resources in India. Chairperson of an Indian NGO "Fluorosis Research And Village Development Foundation" said， the fluorine content in waters of several provinces in India exceeds 48 mg.， and reaches 32 mg. even in the capital city New Deli.
The fresh water reservoir of India with 16% of the world population only accounts for 4% of the total amount in the world， and 40% of the surface and underground water can not be drunk because of geological and terrain factors. The fresh water resource is extremely scarce in India. And with the industrialization process， many unpurified poisonous effluents and family sewage flew into the lakes and permeated to the underground water zone， making the situation even worse. There is virtually no tap water system in villages in India， and many villagers only have access to heavily polluted underground water； while the cities lack maintenance of water supply system， there are only several hours of tap water supplied. Wealthy families have large reservoir of bottled waters， while poor families have to rely on water pumps to extract underground water. "Water Support Organization" report said， there is no split-flow treatment to separate feces and drinking water in many regions in India， and the purification facilities are usually so expensive that some are even illegally sold. The local religion and custom do not favor people to use washroom and other sanitation facilities. And women and children can run into danger when using these facilities， which greatly affect the health of Indian people. Till now， 76 million Indians do not have access to safe water， 10 million people are exposed to danger of arsenic poisoning， and 37.7 million are bugged by the diseases caught by impure drinking water. Over 140，000 children under five years old were died of diarrheal， causing a 600 million USD economic loss. Hence， there is still a long way to go for the drinking water to reach the WHO standard in developed or developing countries.
Pollution source， prevention and control
Water Quality Code of Drinking Water said， pathogen latent in the surface water comes from the pollution brought by urban sewage， agricultural sewage， sewer facilities in public restrooms， contact with wildlife and livestock； while germs in underground water mainly comes from polluted and discarded wells， drinking pipeline， soil fertilization， concentrated feeding of livestock， etc. "Feces are the sources of virulent germs， virus， protozoa， worms"， and climate and environment provide the external condition for the growth of microorganism. The above cases of bacteria poisoning in drinking water show that， higher content of flora often take place in the hot and wet seasons which are good for propagation， which are caused by the permeation of life and excretion sewage into the water pipeline or sources of drinking water.
The chemical component source in the drinking water are the same with some harmful bacteria， which were caused by life and agricultural sewage， natural deposit， climate impact， industrial effluents， pesticide application， water treatment materials， water-soluble pesticide used for public sanitation， and blue-green algae resulting from lake eutrophication.
So the government should make investment to ensure the quality of the water source， improve the purification technologies of the drinking water， strictly supervise the transportation utilizing process and make a good work on water quality supervision and facilities maintenance.
The scandal in Hong Kong， on one hand， showed the concern of the folks and authorities on water quality detection， which has helped spotted and solved the problem in no time； on the other hand， also showed the loopholes of the construction unites and governments in construction and supervision. Technological Director of Licensed Water Affair Professional Society Qi Deming said， the Hong Kong Water Affairs Rules and Housing Construction Contract require water pipes to use non-toxic materials， and the lead solder is banned. Tin content in the solder which sealing the water pipelines should be 99%. However， some companies buy cheap tin pieces to make homemade soldering tin with only 90% of tin content to save cost. The other contents may be heaveymetal like lead， which can cause lead residue when workers fuse tin pieces and solder pipelines. Besides， the regulation in Hong Kong is weak， pipeline workers can be employed to repair or install pipelines only with a technician license， which adds the risks. Hence， the director of the Bid inviting team of Hong Kong Housing Authority Zhang Datang said， they will put soldering materials into the scope of inspection， add 4 heavy metal including lead into the materials to be monitored in checking and accepting newly built buildings. And it requires contractors to do on-site test to prove there is no lead in the soldering materials.
Individuals can also play a part to safeguard the quality of drinking water. Director of sanitation research center of Kaohsiung Medical College in Taiwan professor Hong Yuzhu suggested， it's better to boiled the water which are taken two minutes after the tap water is turned on to 100℃， then open the lid boil it for another three minutes. This can largely reduce cancerogen content and kill germs. When closing the tap water connected by rubber pipes， we should take out the rubber pipe from the water to avoid reverse siphonage where water effluent can reflux and drag up to pollute the water supply pipe. Families with impounding reservoir should cover iron lid on the water pool to guard against the feces of birds or rotten leaves to pollute the water. The water reservoir should be cleaned up at least every half year to avoid the growth of algae. Household water filter should also be replaced frequently to avoid the reproduction of germs.