environmental problems behind the great wall

6
f m e Focus Environmental Problems behind the Great Wall China is a rapidly developing country with one-fifth of the world's population. The country faces major social and political problems, which have gained the world's attention. Equally challenging are serious environmental problems resulting from overpopulation, rapid industrialization, and overuse of natural resources that could potentially threaten the health of China's 1.2 billion people, whether they live in cities or the rural countryside. The most serious environmental health problem, say Chinese environmental health experts, is air pollution. One example is Taiyuan, the capital of Shanxi Province and an ancient fortified city located in a valley. Iron, steel, and chemical factories spew soot, fly ash, and sulfur dioxide into the air, and the pollutants are trapped within the valley and the walls of the city, according to the Chinese National Environmental Protection Agency (NEPA). Two million people live in Taiyuan. Indoor air pollution is also a serious threat. Women in rural Xuan Wei County of Yunnan Province have the highest lung cancer rate among Chinese women, even though few smoke. The greatest cancer risk is among residents who burn smoky coal inside their homes with no ventilation. The Chinese Academy of Preventive Medicine says thousands of Chinese in other rural areas suffer debilitating diseases from burn- ing coal containing arsenic and fluoride. Most factories built before the 1980s have no pollution control equipment and are fueled by coal, which the government calls "the chief source of air pollution in China." According to Vaclav Smil, professor and author of China 's Environmental Crisis, "Burdens of air pollution are not surprising in a nation where combustion of one billion tons of coal, largely uncleaned and burned with minimal or no pollution controls, sup- plies three-quarters of all primary energy." As a result, numerous cities in China exceed World Health Organization air pollution guidelines. Statistics show high morbidity and mor- tality from lung disease in China. Respiratory disease is one of the leading causes of death overall in China. It is the primary cause of death among rural resi- dents, who have a mortality rate of 168 per 100,000 people. Cancer is the primary cause of death among urban residents, who have a mortality rate of 126 per 100,000 according to the 1992 Report on the State of the Environment in China, published by NEPA. "Environmental pollution and unhealthy habits are the main causes of dis- ease," the report concludes. "Unhealthy habits" include smoking-a habit shared by 300 million Chinese. An estimated two mil- lion Chinese a year will die from smoking by the year 2025 if the current rate of tobacco use persists. China's second most serious environ- mental health problem is water pollution. Waterborne illnesses, from sewage and agri- cultural waste contaminating the water sup- plies, cause thousands of deaths from infec- tious disease per year. Rivers used for drink- ing water also become polluted with indus- trial discharges, according to Bai Changbo, NEPA's Foreign Affairs Officer. Says Changbo, "Much of China's surface water is contaminated with heavy metals, includ- ing lead, cadmium, and arsenic, from industrial effluent." Smoking gun. Women in Xuan Wei who cook with smoky coal have the highest lung cancer incidence of Chinese women. Economy versus Environment At the same time that even state-run enter- prises are fouling the air and water, the gov- ernment is moving full-steam ahead on eco- nomic reforms and its plans for rapid expansion. For example, a $700-million petrochemical plant is under construction in the port city of Tianjin, described by the Wall Street Journal in an article 4 August 1993 as "the first of 14 [chemical] plants China plans to build by 1996." With increasing foreign investment and skyrock- eting growth rates (China now boasts a GNP ranked by some as third in the world), the standard of living for China's 1.2 billion people is rapidly rising. Even the government admits that the country is paying a price for its rapid Environmental Health Perspectives 154

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Page 1: Environmental problems behind the Great Wall

f m e

Focus

Environmental Problems behind the Great WallChina is a rapidly developing country withone-fifth of the world's population. Thecountry faces major social and politicalproblems, which have gained the world'sattention. Equally challenging are seriousenvironmental problems resulting fromoverpopulation, rapid industrialization, andoveruse of natural resources that couldpotentially threaten the health of China's1.2 billion people, whether they live incities or the rural countryside.

The most serious environmental healthproblem, say Chinese environmental healthexperts, is air pollution. One example isTaiyuan, the capital of Shanxi Province andan ancient fortified city located in a valley.Iron, steel, and chemical factories spew soot,fly ash, and sulfur dioxide into the air, andthe pollutants are trapped within the valley

and the walls of the city, according to theChinese National Environmental ProtectionAgency (NEPA). Two million people live inTaiyuan.

Indoor air pollution is also a seriousthreat. Women in rural Xuan Wei Countyof Yunnan Province have the highest lungcancer rate among Chinese women, eventhough few smoke. The greatest cancer riskis among residents who burn smoky coalinside their homes with no ventilation. TheChinese Academy of Preventive Medicinesays thousands of Chinese in other ruralareas suffer debilitating diseases from burn-ing coal containing arsenic and fluoride.Most factories built before the 1980s haveno pollution control equipment and arefueled by coal, which the government calls"the chief source of air pollution in China."

According to Vaclav Smil, professor andauthor of China 's Environmental Crisis,"Burdens of air pollution are not surprisingin a nation where combustion of one billiontons of coal, largely uncleaned and burnedwith minimal or no pollution controls, sup-plies three-quarters of all primary energy."As a result, numerous cities in China exceedWorld Health Organization air pollutionguidelines.

Statistics show high morbidity and mor-tality from lung disease in China.Respiratory disease is one of the leadingcauses of death overall in China. It is theprimary cause of death among rural resi-dents, who have a mortality rate of 168 per100,000 people. Cancer is the primarycause of death among urban residents, whohave a mortality rate of 126 per 100,000according to the 1992 Report on the State ofthe Environment in China, published byNEPA. "Environmental pollution andunhealthy habits are the main causes of dis-ease," the report concludes. "Unhealthyhabits" include smoking-a habit shared by300 million Chinese. An estimated two mil-lion Chinese a year will die from smokingby the year 2025 if the current rate oftobacco use persists.

China's second most serious environ-mental health problem is water pollution.Waterborne illnesses, from sewage and agri-cultural waste contaminating the water sup-plies, cause thousands of deaths from infec-tious disease per year. Rivers used for drink-ing water also become polluted with indus-trial discharges, according to Bai Changbo,NEPA's Foreign Affairs Officer. SaysChangbo, "Much of China's surface wateris contaminated with heavy metals, includ-ing lead, cadmium, and arsenic, fromindustrial effluent."

Smoking gun. Women in Xuan Wei who cook with smoky coal have the highest lung cancer incidence ofChinese women.

Economy versus EnvironmentAt the same time that even state-run enter-prises are fouling the air and water, the gov-ernment is moving full-steam ahead on eco-nomic reforms and its plans for rapidexpansion. For example, a $700-millionpetrochemical plant is under constructionin the port city of Tianjin, described by theWall Street Journal in an article 4 August1993 as "the first of 14 [chemical] plantsChina plans to build by 1996." Withincreasing foreign investment and skyrock-eting growth rates (China now boasts aGNP ranked by some as third in theworld), the standard of living for China's1.2 billion people is rapidly rising.

Even the government admits that thecountry is paying a price for its rapid

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9L1 igrowth. "While the government is puttingmore and more attention on environmentalpollution, industry is attaching moreimportance to economic development," saysChangbo, adding that both state-run andjoint ventures often ignore the strict stan-dards NEPA sets. "If you talk with themanager of an enterprise, the first questionis about production and money; you haveto remind him to consider the environ-ment," said Changbo. That attitude couldchange as China seeks international help forits environmental problems. Already theWorld Bank has committed record amountsof money to China, $300 million in 1993alone, to strengthen the government's envi-ronmental protection programs.

By urging Chinese enterprises to bemore environmentally responsible, someU.S. firms also hope to turn a profit. InBeijing, American businessman HusaynAnwar has set up an environmental consult-ing firm, emphasizing the long-term cost-effectiveness of pollution control. Othercompanies hope to locate markets for emis-sion control devices. Fortune magazinereported 23 August 1993 that a delegationof American firms visited China in June1993 to evaluate demand for their coal-cleaning equipment.

Ambient Air PollutionThe rising standard of living and influx ofbusiness people and tourists means moreautomobiles in China-and dirtier air. In1992, one million vehicles were manufac-tured in China. In Beijing today there are11 million people, 8 million bicycles, andfewer than 1 million cars. But that's sixtimes as many cars as just two years ago.Now at rush hour the city has bumper-to-bumper traffic, with bicyclists fighting25,000 taxis.

Cars in China run only on leaded gaso-line. The mean blood lead levels of residentsin major cities already appear to be slightlyhigher than in the United States, althoughfew comprehensive studies have been con-ducted on sources of lead exposure. Morecars with leaded gasoline will add to thelead body burden.

For now, the two main sources of airpollution are industrial emissions and theburning of coal (in homes, industry, andpower plants), and the two most significantair pollutants are suspended particulatematter and sulfur dioxide. Annual meanambient air levels of total suspended partic-ulates (TSP) in U.S. cities typically arebetween 30 and 75 micrograms per cubicmeter (pg/m3). NEPA reports annual dailyaverages of 403 pg/m3 in northern Chinesecities and 243 pg/M3 in southern cities. In1987 the EPA abandoned its TSP standardof 75 jig/m3 in favor of a PMIO standard(TSPs smaller than 10 microns) of 50

,ug/m3. William Hunt, chiefof EPA's Monitoring andReports Branch, says theChinese do not yet mon-itor for PM10, so they areunable to look at the parti-cles of greatest concern-those smaller than 10microns-which can moredeeply penetrate the lung.

For sulfur dioxide,NEPA reports an annual Niu Shiru-Milliaverage of 95 pg/m3 in large ese people arurban areas of China; in posed to envU.S. cities the annual aver- contaminants.age for sulfur dioxide levelsis 21 pg/m3. The EPA's annual mean stan-dard for sulfur dioxide is 80 ,ug/m3. NEPAsays southern Chinese cities suffer frequentacid rain because of the sulfur dioxide emis-sions, which also present a global threat.

Ambient levels of sulfur dioxide andTSPs rise when coal is burned insidehomes. According to Niu Shiru, honorarydirector of the Institute of the Environmentand Engineering at the Chinese Academy ofPreventive Medicine, Beijing has two peaksof ambient sulfur dioxide: one at breakfasttime and the second at dinner. In a jointHarvard University-Beijing MedicalUniversity study, researchers Xu Xiping andWang Lihua reported that high indoor andoutdoor particulate levels in Beijing wererelated to increased chronic respiratory ill-ness. Another study in Beijing found that adoubling of the ambient sulfur dioxide lev-els raised the risk of mortality by 11%.

EPA epidemiologist Robert Chapmanand colleague William Wilson are studyingacids and particulates in the ambient air offour Chinese cities. Their initial work (incollaboration with local environmental offi-cials in China and U.S. scientist Paul Lioy),

lionse beviron

measured lung function of chil-. dren attending schools in theL urban core of Wuhan, China's

fifth largest city, and in a suburb.Similar percentages of children

D from each area lived in homeswith smokers and with coal heat-ing. Coal emissions were oftenvented to the streets. In 1988,TSP levels averaged 251 ,ug/m3near children's homes in the

of Chin- urban core and 110 pg/m3 in thebeing ex- suburb. By contratst, U.S. levelsmental in urban areas average 30-75

,ug/m3. Levels of sulfur dioxideand nitrogen oxides were also

higher in the city core.Initial results show that pulmonary

function was lower in urban than in subur-ban children. They also show that boys andgirls have similar lung function in secondgrade, but that by sixth grade, the girls'average level has dropped 15%, and forboys, 5%. Wilson says the results suggestthat urban air pollution exposure in Chinacontributes to retarded development of chil-dren's lungs. Longitudinal studies areunderway.

Other industrial emissions also createair pollution threats. For example, arsenicemissions from metal smelting operationsand foundries are creating "community pol-lution" in an area of Yunnan Provinceknown for its tin mines, according toBeijing Medical University professor WangZhengang. Studies in the 1980s showedthat tin miners have an increased risk oflung cancer, associated with exposure toinorganic arsenic and radon (along withsmoking). "Now 400 residents in Gejiu suf-fer from arsenic poisoning and skin ker-atoses from exposure to arsenic in air andsurface waters," says Wang. His research

Flunking the test. Schoolchildren in Wuhan suffer reduced lung function.

Volume 102, Number 2, February 1994 155

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group at Beijing Medical University is alsostudying blood lead levels among residentswho live near the smelters and foundries.

Indoor Air PollutionThe air inside Chinese homes often is sig-nificantly worse than the air outside. Onestudy measured levels of sulfur dioxide ashigh as 860 pg/m3 in urban homes withcoal stoves (compared to the nationalaverage of 95 pg/m3 in ambient air andthe U.S. annual mean of 21 ,ug/m3.) Inone study, adults living in residential areasof Beijing (where coal stoves are used byhalf of the residents) were found to sufferreduced pulmonary function.

Visitors to Beijing are struck by thesight of piles of coal briquettes stackedagainst walls of homes and restaurants.Zhang Ji-Qiang, senior advisor for theRockefeller Foundation's Global Environ-ment Program, credits the ChineseMinistry of Agriculture with having devel-oped a more efficient coal briquette thanthe ones currently used in Beijing. Thenew ones are made of smokeless, powderycoal mixed with clay and are designed toreduce particulate emissions by 75%when used properly. Zhang says a demon-stration project is underway in 100 coun-ties.

In rural areas, many families burn coalor wood, without ventilation, in shallowpits dug in the floor. Culture and customshave made the unventilated pits an impor-tant part of rural life, says Zhang. "Mealsare cooked on the fire, people share storiesof their day, pipes are smoked around thepit, food is dried above the fire, and bedsare warmed by the heat. There is even afire goddess whom some worship."

JI"A - UL. 0

Lung cancer, smoky coal, and PAHs.Xuan Wei county has one million people,most of them farmers, who use unventilatedstoves or pits like the ones described byZhang. The area has provided a uniqueresearch setting for studying the healtheffects of three fuels: smoky coal, smokelesscoal, and wood. In addition, the populationis stable, there are few industrial facilities,and the county has one of the highest lungcancer rates in China.

Professor He Xingzhou and his col-leagues at the Chinese Academy ofPreventive Medicine's Institute ofEnvironmental Health and Engineeringbegan studying Xuan Wei in the 1970s;EPA researchers joined as investigators in1982. He's landmark work, much of it incollaboration with EPA scientists RobertChapman, Judy Mumford, and colleagues,demonstrates that nonsmoking womenexposed to indoor coal smoke have anextremely high risk of lung cancer. Lessthan 1% of the Xuan Wei women smoke.In one of the smoky coal-burning com-munes of Xuan Wei, women had a lungcancer rate of 126 per 100,000 women-21times higher than the 6 per 100,000 rate ofwomen in the United States. The rate formen was four times higher than that forU.S. males.

Levels of suspended particulates insidehomes burning coal were as high as 24.2gig/m3, 35 times higher than the peak levelscurrently found outdoors in the most pol-luted Chinese cities. Everyone in a family isexposed to the smoke, says He, but womengenerally spend more time inside the home,and they traditionally do the cooking.During the last decade, many of the XuanWei homes have installed chimneys to vent

Odds stacked against them. Coal briquettes stacked against a restaurant in Beijing are a reminder of thecause of China's worst air pollution.

coal and wood smoke.The Chinese/EPA collaborative research

is an interdisciplinary project involving epi-demiology, environmental measurements,chemistry, and toxicology. Chapman saysone of the investigators' major challengesnow is to analyze coal samples and the com-plex chemical mixtures of coal combustionproducts collected in Xuan Wei.

Toxicologic studies by Mumford andcolleagues JoEllen Lewtas and JaneGallagher found that extracts of indoor airparticles (measuring less than 10 microns)containing polycyclic aromatic hydrocar-bons (PAHs) from Xuan Wei homes arepotent tumor initiators in mice. They arenow studying DNA adducts as qualitativebiomarkers for human exposure to PAHs inthe Xuan Wei population. A recent studyshowed detectable DNA adducts in a higherpercentage of Xuan Wei women exposed tosmoky coal or wood dust than in Beijingwomen using natural gas.

Among urban residents, indoor air pol-lution from coal also plays a role in highcancer rates. Researchers studied women inShenyang, which has one of the highestlung cancer rates in China. Their studyfound that 35% of the cancers were relatedto smoking, but it also implicated air pollu-tion from coal-burning stoves underneathbrick beds ("kang"), as well as cooking-oilemissions.

Air quality will improve only if homesstop uncontrolled use of coal for fuel. But afull-scale changeover is not likely to happensoon. A government report observes: "Coalwill continue to be China's primary sourceof energy for a considerable length of time,so in the absence of major breakthroughs incombustion technology and in coal conver-sion, atmospheric pollution and the acidrain hazard are likely to worsen."

Arsenic in air. Some geographical areasof China contain naturally high levels ofarsenic and fluoride. Concerned about theeffects of exposures to arsenic and fluorideon rural villagers, Professor Niu traveled toseveral Western countries in 1993, trying tointerest scientists in examining the prob-lems. The most serious arsenic exposures,Niu says, occur when villagers burn arsenic-tainted coal in open stoves.

One of the most severely affected areasis Guizhou Province, where Niu estimatestwo million people are exposed to danger-ous levels of arsenic in the indoor air. Somevillagers in the province, one of China'spoorest, also drink arsenic-tainted water.People exposed to arsenic in the area arereported to develop keratoses and skin can-cer.

Fluoride in air. Niu and his colleaguesare also studying two types of fluorosisinduced by exposure to excessive fluoride infood, water, or smoke: dental and skeletal

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3e,SEei ins S i:5S3

fluorosis. Dental fluorosis results in mot-tling (pitting or staining) of teeth; skeletalfluorosis results in spinal deformities thatcause a permanently stooped-over posturein adults. Researchers at the Institute ofEnvironment and Engineering say in someremote villages nearly all residents haveskeletal fluorosis, although some of theseabnormalities are detectable only by X-ray.According to Niu, "Millions of people areexposed to excessive fluoride in water, food,and air in Sichuan Province alone."Professor He adds, "Some people areexposed when they hang corn to dry insidetheir homes; particulates that settle on thecorn may be contaminated with fluoride orarsenic.

Research on Other Indoor PollutantsA study in Beijing Medical Universityfound levels of carbon monoxide as high as47 ppm in homes using coal for heating, alevel almost as high as the U.S. OSHA 8-hour standard of 50 ppm for workplaceexposures. When central heating was intro-duced to some homes, levels of carbonmonoxide dropped dramatically.

In Shenyang, researchers linked thenumber of meals deep-fried in oil (and thesmokiness when cooking) to the risk of lungcancer. Researchers from the ShanghaiCancer Institute and the U.S. NationalCancer Institute analyzed condensates fromcooking oil-emissions (rapeseed and soyaoils) and found they were toxic to humans.The researchers suggested reducing cookingtemperatures to prevent exposures.

David Christiani and colleagues atHarvard are looking at pesticide exposure ina rural county of Anhui Province, wherelarge quantities of organophosphates andcarbamates are used. One issue they areexploring is whether children are exposed topesticides in the home through contact withparents' contaminated clothing.

China has large deposits of asbestos, andoccupational studies have found increasedcancer and respiratory disease among work-ers. Investigators also have discoveredindoor and outdoor asbestos exposure in arural southwestern community, Da-yao.The land surface is naturally composed ofsoil and crocidolite asbestos, which villagerscall "blue clay." Residents used the clay tostucco houses, pave roads, and build stoves,which were later discarded on the land. Of2000 residents examined, 16 had asbestosisand 232 had pleural plaques.

Water PollutionMost cities and villages do not have sophis-ticated sewage treatment facilities, so watersupplies often become contaminated withbacteria and viruses. Sewage contaminationof a sea bed from which clams were harvest-ed was associated with 300,000 cases of

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9El

He Xingzhou (right) with student Lan Cling-Women who cook and spend more time in the home may beat greater risk from smoky coal.

hepatitis A in a 2-month period inShanghai in 1988. Industrial discharges fur-ther contaminate water supplies.

The 1992 NEPA report labels river afterriver as "seriously polluted." The most fre-quently named pollutants are ammonianitrogen, volatile phenols, heavy metals,arsenic, cyanides, petrol pollutants, andoxygen-causing organic matter. NEPAnotes that nearly 2 million pounds ofarsenic and 130 million pounds of "petrolpollutants" were discharged into rivers in1992. In freshwater lakes, pollution byheavy metals such as mercury and hexava-lent chromium is quite serious. Elevatedlevels of mercury have been detected in fish-ermen eating mercury-contaminated fish.

Arsenic and fluoride also occur naturallyin water supplies in certain provinces ofChina. At high levels in drinking water,both can be harmful. NEPA authorities saythat these two elements are not a nationalpriority because they are found at excessivelevels in only a few rural provinces. Chinesescientists, however, say arsenic and fluoridein water, as well as in air, can cause devas-tating effects on rural residents.

Arsenic contamination. China's arsenicstandard for drinking water is the same asEPA's: 50 pg/m3. Niu has received reportsfrom Inner Mongolia and Xinjing Provincethat the standard may be exceeded by10-100 times in drinking water. He isattempting to validate the analytical tech-niques used in these remote areas.

Scientists from the United States,Taiwan, and China are all exploring poten-tial collaborative projects in Inner Mongolia

to study arsenic exposures and evaluatehealth effects. Evidence is too preliminary,says Niu, to know if there are internal can-cers such as those reported by C.J. Chenand colleagues in Taiwan, although a smallnumber of cases of skin lesions (keratoses)and blackfoot disease, a gangrenous circula-tory problem previously documented inTaiwan, have been detected (see box).

Excess fluoride. Millions of Chinese vil-lagers drink water containing high levels(4-10 ppm) of naturally occurring fluoride.Scientists Cao Shouren, Liang Chaoke, andothers from the Chinese Academy ofPreventive Medicine's Institute ofEnvironmental Health and Engineering arecollaborating with George Stookey ofIndiana University School of Dentistry on astudy of two rural Chinese counties. In theChinese counties studied, none of the resi-dents drinking low-fluoride water (upperlimit of 1 ppm) had evidence of skeletal flu-orosis; 87% of villagers drinking high fluo-ride water (4 ppm) did. In some of the ruralareas with the highest fluoride levels, thelocal government has been purifying thedrinking water.

Because U.S. residents do not experi-ence skeletal fluorosis at levels of 4 ppm(the current EPA ceiling), the studies noware examining whether malnutrition (espe-cially lack of protein and calcium) can exac-erbate the effects of fluoride.

This study benefits from having subjectswho have been living in the same counties,drinking from the same water supply, andeating a similar diet for more than 40 years.

Aflatoxin, Hepatitis, and Liver CancerFor years scientists have asked questionsabout the role environmental factors mayplay in the high incidence of liver cancer inChina, where primary liver cancer, which israre in the United States, is the third leadingcause of cancer mortality. Now a team ofinvestigators in the United States and Chinabelieve they have an answer: dual exposureto a common mold and to a virus that seemsto magnify the risk of liver cancer.

Millions of Chinese people are exposedto aflatoxin, a mold long suspected of beinga liver carcinogen, and millions more (some-times simultaneously) are chronically infect-ed with hepatitis B, considered a leadingcause of hepatocellular carcinoma. In amajor international research effort, scientistshave conducted landmark studies to sort outthe role each of these risk factors plays in thehigh liver cancer mortality in China.

The international team consists ofresearchers from the University of SouthernCalifornia (USC), Johns Hopkins Univer-sity, MIT, and the Shanghai CancerInstitute. Their ambitious effort, begun in1986, is following more than 18,000 menliving in four areas of Shanghai to detectnew cases of liver cancer as they develop. ByMarch of 1990, 22 cases of primary livercancer had been detected.

At the beginning of the study in 1986,urine samples were collected from allparticipants. By using newly developed bio-marker assays, the researchers were able tolook for urinary aflatoxin metabolites andDNA adducts. Subjects who later developedliver cancer were more likely than controlsto have detectable levels of aflatoxin, itsmetabolites, and DNA adducts in theirurine. The subjects were also tested for thehepatitis B surface antigen (HBsAg); thosewho developed liver cancer were muchmore likely than controls to be positive.Dramatic relative risk results were found.The chance of getting liver cancer doubledfor men testing positive exposed only toaflatoxin biomarkers. The chance increasedfive times if positive only for hepatitis B,and the risk of liver cancer increased by 60times among men positive for both aflatox-in and hepatitis B biomarkers.

The team's paper, published in Lancet18 April 1992, demonstrated the impor-tance of the aflatoxin-DNA adduct to livercancer. Mimi Yu of USC and JohnGroopman of John Hopkins Universitysaid the study team has now detected morethan 50 cases of liver cancer in the groupbeing followed, and the relative risks remainconsistent.

Says Groopman, "As a long-term publichealth measure, hepatitis B vaccinations willhelp reduce the toll of liver cancer in China.But in the short-term we need to design astrategy to deal with the aflatoxin expo-

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9I

sures." He observes that resi-dents cannot simply avoid afla-toxin because in many areas sta-ple foods are nearly always con-taminated with the mold. Thestudy estimated that most afla-toxin exposure is probably frompeanuts and soybeans.

Groopman and colleaguesare now looking at 7000 foodsamples collected in Qidong,north of Shanghai, which alsohas a high liver cancer rate."Residents will be examined foradduct formation in serum albu-

John Groopmneeds a planaflatoxin expo

min and for excretion of DNA adducts inurine at the high point of their annualexposure to aflatoxin-post harvest," saysGroopman. Groopman said that he hopesthe Qidong study "will be a prelude to apossible human liver cancer chemopreven-tion trial of a drug called Oltipraz," addingthat in an experimental study with rats,Oltipraz protected against aflatoxin-induced liver tumors. The aflatoxin bio-markers can be used as intermediate end-points to assess the protective capabilities ofthe drug.

Environmentalists in ChinaChina's environmental movement is in itsinfancy, although some individuals voiceopposition to government environmentalpolices. One of the most vocal environmen-talists is Dai Qing, a journalist whose maintarget has been the Three Gorges Dam, ahuge hydroelectric project that will dam theYangtze River and displace one million resi-dents. Before the Tiananmen Squaredemonstrations in 1989, Dai published abook of essays opposing the dam project.After the uprising, she was imprisoned for10 months as a dissident, and her environ-mental writings were banned.

"Even though we see terrible changesand degradation of the environment withour own eyes, we can't do anything," saysDai. "We cannot express ourselves. Mosttowns have no elections, so you can't evenvote out a government official who is allow-ing pollution." Dai continued, "If a typicalfactory manager is successful producingmore goods at less cost, the central govern-ment will promote him. He has no incen-tive to think about his responsibility to pro-tect nature." Worst of all, she says, "thecommon people don't have the strength toorganize against pollution."

When they do, it sometimes has tragicresults. An Associated Press report last sum-mer described a clash between residents ofLanzhou and workers at a chemical plant.Local government authorities had orderedthe plant closed because it was poisoningthe water and air with sulfuric acid and car-bon disulfide. When the order was ignored,

angry residents blocked truckso- going into the factory. News,2 reports say the residents got

I into a clash with chemicalworkers from the plant, andtwo residents were killed.

International AssistanceMonetary assistance, in theform of loans, is pouring intoChina to help solve environ-mental problems. For example,

ian-China the British Overseas Develop-to confront ment Agency is developing a)sure. 20-year environmental protec-tion plan for the city of Taiyuan. In Benxi,the World Bank is replacing indoor coal-burning heaters and supplying energy toresidents by means of a centralized districtheating system using piped hot water.Smokestacks will help vent cooking emis-sions. The World Bank is also installingemission controls for the central plant andfor nearby coke ovens.

China has become increasingly visibleat international gatherings on global envi-ronmental matters. Chi-na participated in theUN Conference on En-vironment and Develop-ment (the Earth Sum-mit) held in Rio deJaneiro in 1992 and sub-sequently approved anenvironmental strategyfor China, embodied in aset of guidelines called"Priority Activities forSustainable Develop-ment." Priority activitiesinclude abating the pol-lution from smoke dust,limiting the burning ofraw coal powder, vigor-ously developing centralheating, and extendingthe use of coal briquetteswith higher efficiencyand lower emission ofpollutants for industrialand domestic use, as well -as intercepting municipalwastewater from beingdischarged directly intowater bodies and treating The bad side of Vit in a centralized man- say in some villagener. fer skeletal fluoros

luores nesis.

In a report presentedat the Earth Summit entitled 1992National Reports of the People's Republic ofChina on Environment and Development,China voiced its commitment to "propermanagement of the nation's environment

and to making a positive contribution toglobal environmental protection." Thereport also made a plea to the more devel-oped nations of the world: "China is adeveloping country and her current efforts... to protect the environment are facedwith severe constraints of inadequate fundsand lack of advanced ... technologies. Weare hoping that . .. assistance by the inter-national community will be forthcoming."

In addition to monetary assistance,China looks to the international commu-nity, in particular U.S. universities, to trainmany of its best science and technologystudents. The journal Science reported 15October 1993 that a large fraction of themore than 2500 science and engineeringPhDs annually awarded to Chinese citizensare from U.S. universities (with a down-side that fewer than half of those plan toreturn to China). The National Institutesof Health also provides postdoctoral scien-tists from China an opportunity to con-duct one to two years of research while vis-iting the United States. In November1993, 299 Chinese scientists were at NIH

facilities sharing theirexpertise and learning to

_ use NIH research meth-ods and equipment for

a their own studies.I Even with such in-

ternational assistance,ultimately it will requiretremendous effort andcommitment by Chinato meet the environmen-tal protection goals thecountry set for itself atthe Earth Summit inRio. The country's larg-est obstacle to achievingenvironmental protec-

_ii?70f tion is its simultaneouscommitment to eco-nomic progress, laid outin the same Earth Sum-mit presentation: "Asa developing country,China must unswerving-

~ ly give first priority to_ her national economic

development.... Envir-onmental protection ...

ride. Researchers must serve the purpose,arly all adults suf- of promoting economic

progress and improvingthe quality of life."

Therein lies the challenge facing the mostpopulous country on earth.

Andrea Hricko

Andrea Hricko has previously written for EHPabout arsenic.

Volume 102, Number 2, February 1994 159