This patient had an abscess in the right groinand an abscess from an aortoenteric fistulasecondary to an infected graft. He survivedafter removal of the infected aortic graft andbilateral axillofemoral grafting.

Patients with suspected graft infection require urgent assessment inhospital.

AortoentericfistulaThe possibility of an aortoenteric fistula must be considered in any

patient with an aortic graft who presents with a gastrointestinalhaemorrhage. A warning bleed usually occurs before a catastrophichaemorrhage. Emergency admission to hospital is required and -in theabsence of any obvious cause -exploratory laparotomy should be plannedwith the expectation of having to remove the graft and restore the bloodsupply with bilateral axillofemoral grafts.

Conclusion

When there is doubt about a problem aprompt telephone discussion betweengeneral practitioner and surgeon willhelp to resolve it.

This article has discussed the complications of peripheral arterialreconstruction, but the principles apply equally to reconstructions of otherarteries such as carotid, renal, and mesenteric arteries. Arterialreconstructions are complex but they enable an independent mobileexistence for many patients. The common problems are the most simple tomanage. With prompt action the more serious problems can usually beresolved satisfactorily, leading to restoration of function.The histogram is based on data derived from Brewster et al, Arch Surg 1983;118:1104. We thank

Mr A V Pollock for the picture of.colour lymphography and we acknowledge with thanks theassistance of the audiovisual department, St Mary's Hospital, London, in the preparation of theillustrations.Mr Simon RG Smith, FRCS, is consultant surgeon, Selly Oak Hospital, Birmingham, and Mr

John H N Wolfe, FlCS, iS consultant vascular surgeon, St Mary's Hospital, London.

The ABC of Vascular Diseases has been edited by Mr John H N Wolfe.

INDUSTRIALSMOKE.:::.i. =.

British Medical Journal,London WC1H 9JRAlison,Walker, MRCP, formereditorial registrar

Correspondence to:Department of Paediatrics,St Mary's Hospital, LondonW2 INY.

BMJ 1991;303:1391-4

Health and the Environment

Waste disposal: fresh looks at a rotting problem

Alison Walker

Most people take waste disposal for granted, yet itamounts to much more than the weekly collectionof dustbin bags from our doorsteps. Britain aloneproduces more than 2 5 billion tonnes of waste a yearfrom a wide range of sources including mines andquarries, factories, farms, hospitals, and constructionsites (table). Historically, waste has not been disposedof with sufficient care and previous legislation has notbeen completely effective (box).

Air and water pollution, which to a large extent arisefrom waste discharged into the environment, are dealtwith in other articles in this series. The BMA's reportHazardous Waste and Human Health examines theeffect of waste in greater detail.2 This article considerscertain aspects of waste of particular interest to themedical profession.

Clinical wasteClinical waste arises from hospitals, health centres,

general practitioners' and dentists' surgeries, veter-inary surgeries, and from the homes of people withdiseases such as diabetes or with renal failure who treatthemselves. Among the potential risks from clinicalwaste, that from sharps (broken glass, needles, 4ndother sharp instruments) is ofconsiderable concern as asource of bloodborne disease agents such as hepatitis Bvirus and HIV. The risk of seroconversion afterpercutaneous exposure to blood infected with HIV is

only one in 200 but as high as one in five for hepatitis Bvirus. Immunisation against hepatitis B is available toall health workers, but no such precaution can be takenfor HIV infection.3

Medical staff are not the only people at risk of sharpsinjuries in a hospital. During a 10 month study at auniversity hospital in the United States more than320 sharps injuries were reported, of which 13%occurred during or after disposal; most of these injurieswere caused by sharps protruding from rubbishwaiting for disposal.4 Another study, from the Hospitalfor Sick Children, Great Ormond Street, London,

Sources ofwaste, England and Wales

QuantityType (million tonnes/year)

Liquid industrial effluent 2000Agriculture* 250Mines and quarries (including china clay)* 130Industrial 50

Hazardous and special 3-9Special 1i5

Domestic and trade 28Sewage and sludge 24Power station ash 14Blast furnace slag 6Building 3Medical wastes 0-15

Total 2505 15

*Not registered under Control of Pollution Act 1974.

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found that porters and those working in the centralsterile supplies unit had the highest rate of sharpsinjuries.5 At least 37 documented cases of serocon-version after occupational exposure to HIV haveoccurred world wide, most of which were caused bysome form of sharps injury.3 The only way to preventtransmission of infection is to assume that all clinicalwaste is potentially infected and adopt a universal safepractice.

Disposal of clinical wasteIn Greater London alone some 30000 tonnes of

bagged clinical waste are produced every year.6 Theproblem of disposing of such a large volume withoutrisk is considerable.The practice of segregating clinical waste from

domestic and general waste by putting it into yellowbags and containers has been poorly adhered toaccording to evidence presented to the House ofCommons environment committee.' This system wasintroduced in 1982 after concern was raised over theway in which clinical waste was being mixed withgeneral waste. In the south east, in particular, clinicalwaste had been found in public areas, includingholiday beaches. Even by 1989 the problem had notbeen solved. A scandal hit the headlines when clinicalwaste from London ended up on a landfill site licensedfor domestic waste in Cheshire.The London Waste Regulation Authority examined

the disposal of clinical waste in 1989, taking evidencefrom both the public and private sectors.6 It foundmany of the hospital incinerators to be old andoverloaded, producing belching smoke and possiblydioxins, and operating below recommended tempera-tures-partly to economise on fuel. The authority alsofound scenes ofburst yellow bags with their contents ofdirty syringes and dressings spilling out on to the floorbeing handled by inexperienced disposal staff wearingminimal protective clothing. One of the authority'sstrongest recommendations was to reiterate the needfor all clinical waste to be incinerated and not disposedof in landfill sites. For this to happen more incineratorswould need to be built and existing ones brought up tostandard. The BMA's report on hazardous wasteechoed this response, adding that information onexisting incinerators should be pooled.2

The lifting of crown immunity from clinical wastedisposal in April 1991 will allow a welcome and longoverdue review of the system. Hospitals now riskprosecution if they fail to meet the required standardsunder the Clean Air Act 1956 and 1968 and Control ofPollution Act 1974. Managers had until October 1991to submit their programmes for upgrading but haveuntil 1996 to implement the changes-far too longaccording to David Boyd of the National Association ofWaste Disposal Contractors. The association hasproduced guidelines on clinical waste disposal coveringsegregation, packaging, transport, and disposal byhigh temperature incineration. "It's a professionalgame," said David Boyd, "which should not be carriedout by untrained operators running aging inhouseincinerators." The standards defined in its guidelines,says the association, should be adopted by both privateand hospital disposal teams.

Countries like Germany have introduced advancedsystems for treating clinical waste at the site ofproduction.6 The waste is first shredded until it isunrecognisable and then treated with microwavesto ensure thermic disinfection. The waste can then beconverted into granules if necessary and shipped tolandfill sites. The new system can be used for treatingall clinical waste including syringes, needles, anddialysis equipment, and other countries like Italy are

already considering introducing it.

Waste from households, shops, and officesThe social reformer Edwin Chadwick, working

during the nineteenth century, was one of the firstpeople to link disease and death with poor sanitaryconditions in the streets of Britain. Such conditions arenow largely a thing of the past as local authority andprivate dustcarts regularly collect rubbish fromhouseholds, shops, and offices. Thanks to this generallyefficient service, very little harm actually comes fromsolid municipal waste. Problems can still arise whenthe waste is not collected during times of industrialaction. A strike by refuse collectors in Liverpool

BMJ VOLUME 303 30 NOVEMBER 1991

Control ofwaste disposalSpecific waste disposal legislation in Britain is relativelyrecent but has taken several leaps forward since it wasfirst introduced-in the early 1970s. The first act aimedspecifically at waste disposal was the 1972 Deposit ofPoisonous Waste Act, passed after the discovery ofdrums of cyanide in a children's adventure playgroundin the Midlands.The 1972 act was replaced by the more compre-

hensive Control of Pollution Act in 1974. This wascriticised by the House of Commons EnvironmentCommittee in 1989.' According to the committee, theinadequacy ofthe regulations governing waste disposalhad had serious consequences. Waste disposalauthorities had acted as both poacher and gamekeeper-both operating and regulating waste disposal sites.Unscrupulous operators had been allowed "to dumpwaste, almost unchecked, because of variations inlicensing and loopholes in the Control of Pollution Act1974."The 1990 Environmental Protection Act, the latest

piece oflegislation governing waste disposal in Britain,is intended to correct earlier deficiencies. One ofits successes has been to separate out the roles ofregulator and operator; regulation has become the soleresponsibility of waste regulation authorities, policedby organisations such as Her Majesty's Inspectorate ofPollution and the National Rivers Authority, anddisposal is carried out by waste disposal authoritiesand private contractors. An important theme of theEnvironmental Protection Act has been the control ofwaste from the "cradle to the grave."

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Little is known about long term health effects oftoxic waste

during last summer left rotting piles of rubbish on thestreets, posing a health threat from the multiplying ratpopulation, which acts as a reservoir for diseases suchas leptospirosis.7 Even without industrial action ahealth risk arises when unhygienic conditions allowcockroaches and fly populations to multiply amongrefuse since almost every known excreted pathogen hasbeen isolated from these vectors.8

Fly tipping, or the illegal dumping of waste fromboth domestic and industrial sources, is a considerableproblem in urban areas.9 Far from being innocuous,fly tipped waste has been found to be "extremelyhazardous," according to Mr Bill Townend of theLondon Waste Regulation Authority. A study carriedout in London the 1980s, he said, found that 17 out of58 sites of fly tipped material analysed were heavilycontaminated with toxic substances such as heavymetals and posed a potentially serious risk to publichealth.

Hazardous industrial wasteHazardous industrial waste has a high public profile

and is therefore the main subject for public concernabout safety of waste and its disposal. There have,however, been hardly any studies to provide scientificevidence to support this concern, and many of thoseexisting are of poor quality.6

Tracing the cause of disease in an individual toprevious exposure to a waste product is extremelydifficult. Research based on exposure to waste productsis limited, and many risk assessments are based on theknown toxic effects of substances found in disposalsites, such as asbestos. This does not take into accountthe effects of mixing substances-the "cocktailcompounds"-or the unknown nature of much wastematerial. Animal tests of toxicity have been used tostudy the effect of waste products in mammals, butthey have limited application to humans. Thoughacute exposure to toxic substances may have clearcut effects, such as the respiratory and autonomicsymptoms after poisoning with organophosphates,the effects of long term exposure are much moreproblematic and, with regard to public health, far moreserious. Epidemiological studies may provide some ofthe answers but numerous confounding factors makethe results difficult to interpret.A Swedish study looked at the mortality among

workers at a municipal waste incinerator. '° Employ-ment records dating back to 1951 were used to identify

subjects for the study. More than 170 workers wereidentified who had been exposed to substances such aslead, mercury, cadmium, and carbon monoxide. Anincreased risk of lung cancer and ischaemic heartdisease was found in the workers, thought to be causedby high occupational exposure to dust and gases at theincinerator. Although the study was criticised forbeing small, retrospective, and not fully adjusted forconfounding factors, it is one of the few available onworkers in the waste industry.

Extrapolating any study to the general population isfraught with problems. Toxic substances such asfurans, dioxins, and polychlorinated biphenylsare ubiquitous in the environment and can makeinterpreting exposure difficult. Furthermore thetechnical means to detect trace amounts of manycontaminants has outstripped the ability to predicttheir health risk.

Dioxin has become one of the more notorious toxicsubstances following the accident at a chemical plant atSeveso in Italy in 1976 when dioxins were releasedinto the atmosphere. Dioxin is a generic term for75 closely related compounds, the best known ofwhichis 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD).Dioxins are produced as a result of the combustion oforganic material such as wood or the incompletecombustion of certain hazardous materials, includingpolychlorinated biphenyls. Experiments in animalshave shown dioxins to be teratogenic and carcinogenic,but the results in humans are not as clear. A recentlarge study in the United States looked at more than5000 workers exposed to dioxins at 12 industrialplants." The results overall were equivocal, but theydid show a slight but significantly higher mortalityfrom all cancers than expected-questioning the beliefthat low exposures are entirely safe.

Waste disposal sitesIn Britain, about 90% of waste from factories,

households, shops, and offices is taken to one of the4000 or so controlled landfill sites for disposal. Mostof the remainder is burned, either in a municipalincinerator or in one of the four specialised hightemperature incinerators which deal with toxic waste.This contrasts with practice in many Europeancountries-for example, Sweden-where some 60% ofmunicipal waste is incinerated.The transport and disposal of some toxic waste is

carefully controlled under special waste regulations,which are part of the Control of Pollution Act 1974.The regulations cover the disposal of medicinalproducts available only on prescription, specifiedmaterials which are dangerous to human health, andsubstances with a flash point of 21 "C or less. Specialdocumentation-a consignment note-is required sothat the waste can be tracked from the premises of thewaste producer to the point of final disposal.Most people are suspicious of landfill sites and

incineration plants which deal with waste. TheNIMBY (not in my back yard) syndrome sums up mostpeople's attitude towards them. A survey by theDepartment of the Environment in 1990 found thedisposal of hazardous waste to be the public's biggestenvironmental concern-ranking higher than acidrain or pesticides.'2 "In the public mind it wouldappear that waste disposal sites are viewed as part ofthe problem of hazardous waste rather than as thesolution," says the BMA in its review of hazardouswaste and health.2 But is the public right to be soconcerned about waste disposal sites?

LANDFILL SITES

Landfill sites present three potential hazards-ground water pollution, land contamination, and

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Many hospital incinerators are Zold and overloaded

generation of explosive landfill gas. Contamination ofground water, when it occurs, presents a considerableproblem since ground water is the source of about athird of the drinking water supply in England andWales. Halogenated organic compounds, in particular,are very mobile in soils and can move into ground watereasily. Traces have been found in many of the aquifersin Britain, especially those in old industrial regions.Modern industrial plants also threaten ground watersupplies-for example, solvents from car manufactur-ing plants were found to be contaminating groundwater in the West Midlands.'3 Legislation does exist toprotect ground water. The European Communityground water directive, for example, restricts the levelof substances allowed to be discharged into groundwater and these substances are monitored by theNational Rivers Authority. Nevertheless, a studycommissioned by the Department of the Environmentin 1987 looked at 100 landfill sites in Britain and foundthat a third had caused contamination of ground orsurface water."4The health risks from low level contamination of

water supplies are not fully known. Studies from theUnited States suggest that drinking private suppliesfrom contaminated well water may be associated withan increase in the incidence of leukaemia, althoughthese results have been disputed.'5 Public watersupplies in Britain are better protected than privatesupplies from wells as they are regularly monitored andtested.A combination of gases, particularly methane, can

build up in a landfill site as landfill gas, with thepotential to cause explosions with serious conse-quences. In 1986 gas escaped from an old landfill siteleading to the explosion and destruction of a bungalowin Loscoe, Derbyshire. The Department of theEnvironment's review of 100 landfill sites found theproblem oflandfill gas to be seriously underestimated. "No gas control measures were found in 70% of sites andmore than 50% lacked gas monitoring bore holes eventhough more than two thirds were within 500 metres ofresidential areas.

Contaminated land from previous indiscriminatedumping of toxic substances can have serious reper-cussions. Love Canal in Niagara City, New York, is anotorious example of this.6 Between 1930 and 1952about 20 000 tonnes ofhazardous waste was dumped inthe canal. It was subsequently filled in and built on.Twenty five years later tests were carried out in the areabecause of foul smelling liquids and sludge had beenfound to be seeping into the basements of houses builton the site. Children were at particularly high riskbecause the school playground was built directlyover the filled canal, and studies have suggested anassociation between living in Love Canal and shortstature in children.'6

Alternative waste disposal optionsIn countries like Sweden domestic waste recycling

schemes flourish and bottle and can banks are a feature

of most neighbourhoods. Britain has lagged behind inintroducing these initiatives, but its new green policyspelt out in the Environmental Protection Act isintended to encourage waste minimisation andrecycling both in industry and in the home. Europeancommissioner for energy and the environment, MrStanley Clinton Davis, advised the House ofCommonsin 1989 that Britain ranked somewhere in the middle ofthe international hierarchy for adequate waste disposalpractices.' It was joined by Belgium, France, Luxem-burg, and Ireland. The best countries includedDenmark and the Netherlands. Furthermore, thecontinued practice of codisposal (the joint disposal ofindustrial and household waste) in Britain has ledothers in Europe to believe that the British are sittingon a time bomb.

ConclusionRecycling schemes aim at reducing the enormous

volume of waste which needs to be disposed of everyday. This should help prevent future waste disposaldisasters like that at Love Canal, but the legacy of pastbad practice and the continued mismanagement oflandfill sites still present health hazards. Much moreinformation is needed before health risks can beidentified with certainty. As one official from theDepartment of the Environment said, "If you ask12 doctors for advice on waste you are bound to get13 different answers." Much more research needs to bedone if the health risks of waste disposal are to beidentified, and in time.

I am grateful to Tara Lamont of the BMA and WilliamTownend of the London Waste Regulation Authority fortheir help in compiling this article.

1 House of Commons Environment Committee. Second report. Toxic waste.London: HMSO, 1989.

2 British Medical Association. Hazardous waste and human health. Oxford:Waste Regulation Authority, 1989.

3 British Medical Association. A code of practice for the safe use and disposal ofsharps. London: BMA, 1990.

4 Jagger J, Hunt EH, Brand-Elnaggar J, Pearson RD. Rates of needlestickinjury caused by various devices in a university hospital. N Engl J Med1988;319:284-8.

5 Waldron HA. Needlestick injuries in hospital staff. BMJ 1985;290:1285.6 London Waste Working Party. Clinical waste-an appraisal. London: London

Oxford University Press, 1991.7 Lowry S. Sanitation. BMJ 1990;300:177-9.8 World Health Organisation. Urban solid waste management. Florence: World

Health Organisation, 1991.9 Royal Comntiission on Environmental Pollution. Eleventh report, managing

waste: the duty ofcare. London: HMSO, 1985.10 Gustavsson P. Mortality among workers at a municipal waste incinerator.

Amj IndMed 1989;15:245-53.11 Fingerhut MA, Halperin WE, Marlow DA, Piacitelli LA, Honchal

PA, Sweeney MH, ei al. Cancer mortality in workers exposed to2,3,7,8-tetrachlorodibenzo-p-dioxin. N EnglJ Med 1991;324:212-8.

12 Central Statistical Office. Social trends. No 20. London: HMSO, 1990.13 Department of the Environment. Assessment ofgroundwater quality in England

and Wales. London: HMSO, 1988.14 Croft B, Campbell D. Characteristics of 100UK landfill sites. In: Proceedings of

1990 Hanrell waste management symposium. Harwell: United KingdomAtomic Energy Authority, 1990.

15 Lagakos SW, et al. An analysis ofcontaminated well water and health effects inWoburn, Massachusetts. Journal of the American Statistical Association1986;81:583-6.

16 Paigen B, Goldman LR, Magnant MM, Highland JH, Steegman AT. Growthof children living near the hazardous waste site, Love Canal. Hum Bil1987;59:489-508.

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