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OF PCDD/F in Waste

Evaluation of human health risks

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SWEDISH ENVIRONMENTAL PROTECTION AGENCY Evaluation of human health risks

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Orders

Phone: + 46 (0)8-505 933 40 Fax: + 46 (0)8-505 933 99

E-mail: natur@cm.se

Address: CM Gruppen AB, Box 110 93, SE-161 11 Bromma, Sweden Internet: www.naturvardsverket.se/publikationer

The Swedish Environmental Protection Agency Phone: +46 (0)8-698 10 00 Fax: +46 (0)8-20 29 25

E-mail: registrator@naturvardsverket.se

Address: Naturvårdsverket, SE-106 48 Stockholm, Sweden Internet: www.naturvardsverket.se

ISBN 978-91-620-6418-1 ISSN 0282-7298

© Naturvårdsverket 2011

Print: CM Gruppen AB, Bromma 2011 Cover photo: Viktor Sjöblom, Umeå

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Preface

This study was initiated by the Swedish Environmental Protection Agency with the aim to investigate whether the suggested 15 ppb (15 000 ng TEQ kg-1) Low POP Content Limit (LPCL) for dioxin in waste is low enough to protect humans from toxicological health risks. The main focus of the study was to identify and quantify risk scenarios where contaminants originating from wastes are transferred from the environment to human food chains.

The work consisted of three parts:

i) a literature study to collect and analyse existing data and relevant information from the open literature,

ii) two field measurement studies at sites where dioxin contaminated waste is produced and managed, and

iii) a human health risk assessment including prediction of risks on the basis of the field data obtained

Participants in the project were Annika Åberg (Umeå University), Karin Wiberg (Umeå University), and Annika Hanberg (Karolinska Institutet).

This report is a first approach to investigate human health risks associated to PCDD/Fs and dl-PCBs in waste and waste management practices in the society. The issue is very complex and is not easily handled since it involves environmental and toxicological sciences as well as political, technical and economical

perspectives. Therefore, the report does not aim to suggest new Low POP Content Limits for PCDD/Fs (or dl-PCBs) in waste, but rather highlight some issues that are important from the human health perspective. Hopefully, the results in the report may lead to stimulation of the scientific community to pick up this topic and develop science based new Low POPs Limits. The results do not reflect risks associated to diffuse pollution of PCDD/Fs or dl-PCBs in the environment and the fact that humans are exposed to environmental background concentrations. The basis for the study was to investigate how point sources may increase

environmental levels and human body burdens in addition to exposure that originates from the atmosphere.

Although the information in this report has been funded wholly or in part by the Swedish Environmental Protection Agency, it may not necessarily reflect the views of the Agency and no official endorsement should be inferred.

Swedish Environmental Protection Agency, March 2011

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Abbreviations

BAF Bioaccumulation factor – the ratio of the concentration of a chemical in an exposed organism (all possible exposure routes) and the

concentration of the chemical in an environmental compartment or in food.

BSAF Biota-to-sediment or biota-to-soil accumulation factor - the ratio of the concentration of a chemical in an exposed organism (lipid normalised) and the concentration of the chemical in the sediment/soil (organic carbon-normalised).

BCF Bioconcentration factor - the ratio of the concentration of a chemical in an organism and the concentration of the chemical in the water at steady state.

BIPRO Beratungsgesellschaft für integrierte Problemlösungen, technical consultants in Germany.

b.w. Bodyweight

BTF Biotransfer factor – the ratio of a chemical in an exposed organism and the daily contaminant input flux.

CNP Chlornitrofen, organochlorine herbicide

COR Carry over rate, transfer efficiency between environmental media and biota.

CP Chlorophenol

DDT Dichlorodiphenyltrichloroethane, organochlorine insecticide

dl-PCB Dioxin-like PCBs, a group of twelve PCB congeners that exhibit the same mode of toxic action as PCDD/Fs.

HCH Hexachlorocyclohexane, organochlorine insecticide HpCDD Heptachloro-dibenzo-p-dioxin

HpCDF Heptachloro-dibenzofuran

HxCDD Hexachloro-dibenzo-p-dioxin HxCDF Hexachloro-dibenzofuran

IPEN The International POPs Elimination Network

I-TEF Toxic equivalence factors for calculation of TEQ. Adopted by an international expert group (NATO/CCMS, 1988).

I-TEQ Toxic equivalents, the product of the analytical concentration of a PCDD/F congener and its I-TEF.

LPCL Low POP Content Limit, maximum residue limit for dioxins in waste products where recycling and/or management practices are not restricted.

MSWI Municipal solid waste incineration NGO Non-governmental organisation OCDD Octachloro-dibenzo-p-dioxin

OCDF Octachloro-dibenzofuran PCB Polychlorinated biphenyl

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PCP Pentachlorophenol

PeCDD Pentachloro-dibenzo-p-dioxin PeCDF Pentachloro-dibenzofuran POP Persistent Organic Pollutant

ppb parts per billion, 1 µg kg-1 or 1000 ng kg-1

TDI Tolerable Daily Intake – the tolerable average intake of a compound over a long term that does not result in human health risks.

TCDD Tetrachloro-dibenzo-p-dioxin TCDF Tetrachloro-dibenzofuran

TEQ Toxic equivalents, the sum of the products of the analytical

concentrations of each dioxins or dioxin-like compounds multiplied with their individual TEF.

TWI Tolerable Weekly Intake – the tolerable average intake of a compound over a long term that does not result in human health risks.

WHO-TEF Toxic equivalents factors for calculation of TEQ for dioxins and dioxin-like com-pounds, adopted by WHO.

WHO-TEQ Toxic equivalents, the sum of the products of the analytical

concentration of dioxins and dioxin-like compounds and their individual WHO-TEF.

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Contents

PREFACE 3 ABBREVIATIONS 5 1 SAMMANFATTNING 11

1.1 Dioxinförorenat avfall i befintliga fallstudier 11 1.2 Halter i föda och exponering relaterat till lokala källor 12 1.3 Granskning av BIPROs riskbedömning 13 1.4 Exponeringsbedömning 13

1.5 Syntes 14

2 SUMMARY 17

2.1 Dioxin contaminated waste in current case studies 17 2.2 Food and exposure levels related to local sources 18 2.3 Review of the BIPRO assessment 19 2.4 The exposure assessment 20

2.5 Synthesis 20

3 BACKGROUND 22

4 DIOXINS 23

5 DIOXIN CONTAMINATED WASTE 25

5.1 Waste categories 25 5.2 Residues from thermal processes 26 5.2.1 Concentrations of pollutants 26

5.2.2 Case studies 27

5.3 Impregnated wood and waste wood litter 30 5.3.1 Concentrations of pollutants 30 5.3.2 Case studies 31 5.4 Chemical waste 32 5.4.1 Concentrations of pollutants 32 5.4.2 Case studies 32 5.5 E-waste recycling 33 5.5.1 Concentrations of pollutants 33 5.5.2 Case studies 33 6 HUMAN EXPOSURE 35

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6.2 Exposure routes near local pollution sources 37 6.3 Human body burdens in local contamination scenarios 38

7 FOOD CHAIN CONTAMINATION RELATED TO LOCAL SOURCES 42

7.1 Agricultural food chains 43 7.1.1 Eggs and chickens 43

7.1.2 Milk and meat 45

7.1.3 Factors affecting transfer of soil pollutants to agricultural food chains 46 7.2 The aquatic food chain 49

8 REVIEW OF THE BIPRO RISK ASSESSMENT 51

8.1 Application of safety factors and tolerable daily intake (TDI) 51 8.2 Correlating environmental levels to uptake into eggs 52 8.3 Contribution of dl-PCBs 52 8.4 Exposure from other sources 53

9 CASE STUDIES IN PERU AND THAILAND 54

9.1 Case study 1: Zapallal waste site, Peru 54 9.1.1 Pollution of soil and sediment related to management of ashes 56 9.1.2 Bioaccumulation in biota 58

9.1.3 Conclusions 60

9.2 Case study 2: Phuket MSW Incinerator, Thailand 60 9.2.1 Pollution of soil and sediment related to management of ashes 61 9.2.2 Bioaccumulation in biota 64

9.2.3 Conclusions 64

10 HUMAN EXPOSURE ASSESSMENT RELATED TO

ENVIRONMENTAL CONTAMINATION 65

10.1 Method 65

10.2 Human exposure scenarios 66 10.3 Modelling bioaccumulation and exposure levels 67

10.4 Results 68

10.4.1 Ingestion of eggs 68 10.4.2 Ingestion of milk 69 10.4.3 Ingestion of meat 71 10.4.4 Ingestion of leafy vegetables 72 10.4.5 Ingestion of soil 73 10.5 Critical soil concentration levels 73 10.5 Critical soil concentration levels 74

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11 SYNTHESIS OF THE RESULTS 78

11.1 Risk scenarios 78

11.2 Exposure assessment 80 11.3 Uncertainties in the results 83 11.3.1 Identifying risk scenarios related to improper management of PCDD/F

contaminated waste 83 11.3.2 Correlating environmental levels to human food chain contamination 84 11.3.3 Correlating environmental levels to improper management of waste in

the field studies 84 11.3.4 Human exposure assessment 85 11.3.5 Estimated critical soil concentrations 87 11.3.6 Degree of protection with current Low POP Content Limits 87

12 CONCLUSIONS 89

13 RECOMMENDATIONS FOR FUTURE WORK 91

APPENDIX A 92

Emission and Pollution Problem by dioxin in Peru 92 Introduction 92 Objectives 93 Methodology 93 Location of Zapallal Landfill 94 Description of the storage places of waste and residues 95 Types of identified residues 96

Storage of residues 98

Access to the landfill and the surrounding 99 Acknowledgment 100 References 100 APPENDIX B 102 APPENDIX C 103 APPENDIX C 104 APPENDIX C 105 APPENDIX D 121 REFERENCES 127

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1 Sammanfattning

Syftet med denna undersökning var att identifiera riskscenarier där förekomst av polyklorerade dibenso-p-dioxiner och dibensofuraner (PCDD/F:er) och dioxinlika polyklorerade bifenyler (dl-PCB:er) i avfall orsakar spridning av dessa toxiska föroreningar i miljön och överförs till människor genom föda och andra

exponeringsvägar. Två fältstudier genomfördes på platser där avfall och aska förvaras och hanteras öppet, en i Peru och en i Thailand. Syftet med dessa var att studera graden av inverkan på omgivande miljö.

För att kunna relatera människors exponeringsnivåer till det föreslagna Low POP Content Limit (LPCL)-värdet för PCDD/F genomfördes en riskbedömning med hjälp av en spridnings- och exponeringsmodell (CalTOX) samt med stöd av fältdata från Peru. Genom exponeringsberäkningar uppskattades punktkällors bidrag till

humanexponering utöver den som man oundvikligen utsätts via diffusa utsläpp.

1.1 Dioxinförorenat avfall i befintliga

fallstudier

Vi identifierade fyra avfallskategorier som potentiellt viktiga inom ramen för projektets syfte:

i) förbränningsrester, ii) kemiskt avfall, iii) träavfall samt

iv) avfall från el-avfallsåtervinning.

För kategorierna i, iii och iv finns ett fåtal antal rapporterade nutida fallstudier, medan det för kemiskt avfall framförallt är historiska incidenter som publicerats. Handel med och återvinning av träavfall kan vara av särskilt intresse då ett par nyligen genomförda fallstudier visar att denna avfallsfraktion har kontaminerat födokedjor i

produktionssteget. För aska existerar i huvudsak en fallstudie och den rapporteras från Storbritannien, där bottenaska och flygaska från kommunal avfallsförbränning

användes som gångmaterial inom ett odlingsområde, vilket ledde till kraftigt förhöjda halter i ägg från frigående höns.

Samtliga incidenter som involverar träavfall eller förbränningsrester rapporteras från europeiska länder. Detta utesluter inte att allvarliga riskscenarier kan finnas även för utvecklingsländer. Tvärtom indikerar detta att om dessa problem kan uppstå i Europa, trots en i många fall väl förankrad och tillämpad lagstiftning, är sannolikheten att de ska inträffa i utvecklingsländer med svagare miljöövervakning förmodligen högre. Från dessa områden saknas dock ofta relevanta data. Eftersom flera typer av farliga ämnen kan förekomma i avfall och öppna deponeringsområden finns det en risk för att vissa människogrupper i utvecklingsländer (t.ex. skräpletare) utsätts för förhöjd

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exponering. Hantering av avfall som innehåller PCDD/F kan därför vara ett allvarligt, om än inte väldokumenterat, problem för människor i fattiga länder.

Det är ofta svårt att relatera en miljöpåverkan till hantering av avfall eftersom flera olika föroreningskällor kan existera inom avfallsområdet. Det är t.ex. svårt att skilja på förorening som sker genom spridning av aska från förorening som sker genom

deposition av luftemissioner som orsakats av förbränning av avfall. I fältstudierna från Peru och Phuket kunde därför konsekvenser av öppen och oskyddad förvaring av aska inte utredas separat från luftemissionernas påverkan.

1.2 Halter i föda och exponering relaterat till

lokala källor

Flertalet studier har rapporterat om lokal förorening av mark och vatten som en följd av industriella punktkällor, spill, olyckor eller andra förorenande aktiviteter. Vid sådana platser kan förhöjd exponering av människor förekomma. Ofta är den relaterad till intag av lokalt producerad föda. I vissa fall, där t.ex. luft och jord är kraftigt förorenade, kan även kontakt med den abiotiska miljön, t.ex. intag av jord, ge upphov till hög exponering hos lokalbefolkning.

Alla animaliska livsmedelsprodukter innehåller PCDD/F:er som ackumulerats från omgivningen och som härrör från historiska och dagsaktuella källor. Föroreningsnivån i livsmedel som producerats nära punktkällor är ofta relaterad till förhöjda halter i miljön. Detta kan i sin tur leda till en högre exponering hos människor som bor i närheten av källan jämfört med genomsnittsbefolkningen.

Många studier har visat att intag av lokalt producerade frigående kycklingar/höns och deras ägg utgör ett högriskscenario. Det finns även studier som visar att

bakgrundskoncentrationer i lantliga miljöer utan lokala s.k. hot-spots är tillräckligt höga för att ge upphov till höga halter av PCDD/F i ägg från frigående höns. Det är svårt att prediktera föroreningshalter i ägg med god noggrannhet. Överföringsvägarna mellan miljön och frigående hönor är många och komplexa, vilket innebär att

exponeringsvägarna inte är lätta att beskriva med hjälp av modeller. Olika faktorer, som förorenings-sammansättning, uppfödningsförhållanden, jordtyp och

växttäckningsgrad, m.fl. påverkar bioackumulationen. Resultat från enskilda studier kan därför inte användas för att ta fram generella bioöverföringsfaktorer mellan jord och ägg. Produktion av andra animaliska livsmedelsprodukter, såsom mjölk och kött, utgör också högriskscenarier i närheten av lokala källor.

Enligt födointagsstudier från olika länder har den allmänna befolkningen ofta ett intag av PCDD/F som ligger nära eller överskrider WHO:s tolerabla intagsgränser, TDI, som anger det uppskattade dagliga intag som kan tolereras under lång tid utan att det förväntas ge upphov till hälsorisker för människor. Skillnaderna i intag är dock stora mellan olika länder. Ett fåtal studier har rapporterat om intag och kroppsbelastning i utvecklingsländer. Eftersom födointag och andra levnadsvillkor skiljer sig åt mellan

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olika länder är det inte möjligt att använda data från den industrialiserade världen för att uttala sig om PCDD/F-exponering för människor i utvecklingsländerna.

1.3 Granskning av BIPROs riskbedömning

I den riskbedömningen av PCDD/F som gjordes av en tysk konsultbyrå (BIPRO) på uppdrag av Europeiska Kommissionen utgick man från att det lagstiftade gränsvärdet för kommersiellt producerade ägg är korrelerat till risker för människors hälsa baserat på TDI. Eftersom det lagstiftade gränsvärdet i livsmedel inte grundar sig på en hälsoriskbedömning, kan en jämförelse mellan halter i livsmedel och gränsvärdet inte indikera risknivån avseende hälsoeffekter. Riskbedömningar bör därför inte enbart baseras på denna typ av jämförelser.

I BIPROs riskbedömning utgår man ifrån att en PCDD/F koncentration på 30 pg WHO-TEQ g-1 fett kan accepteras för ägg. Genom att använda överföringsfaktorer mellan jord och ägg (s.k. BTFs, biotransfer factors) från två olika studier uppskattade man att den kritiska PCDD/F koncentration på 30 pg WHO-TEQ g-1 fett i ägg motsvarar en markkoncentration på 1 000 ng TEQ kg (1 ppb).

En konsumtion av ett ägg per dag är tillräckligt för att ge ett signifikant bidrag till TDI om äggkoncentrationen är 3 pg TEQ g-1 fett eller högre. I motsats till slutsatserna i BIPRO-rapporten, tyder dessa intagsberäkningar på att koncentrationer i ägg inte bör vara högre än EU:s gränsvärde (3 pg TEQ g-1 fett). En sammanställning av

litteraturdata och beräknade överföringsfaktorer från jord till ägg baserade på dessa data visade att överföringsfaktorerna varierar i hög grad och att dl-PCB är betydligt mer tillgängliga än PCDD/F. Med hänsyn till den stora variationen kan BTF från ett fåtal studier inte anses representativa för mer generella scenarier. Den

överföringsfaktor som användes av BIPRO låg i det övre intervallet och deras riskbedömning underskattar därför förmodligen risken för upptag i ägg vid markkoncentrationer på 1 000 ng TEQ kg-1 torrvikt (1 ppb). Enligt

överföringsfaktorerna som beräknades i denna rapport kan gränsvärdet för PCDD/F i ägg nås redan vid 1-70 ng TEQ i jorden (0,001-0,07 ppb).

TDI omfattar toxiskt bidrag (TEQ-bidrag) från både PCDD/F och dl-PCB. Bidraget från dl-PCB beaktas inte i BIPROs riskbedömning, vilket ger en skev bild av riskerna.

1.4 Exponeringsbedömning

Inom ramen för denna studie gjordes en exponeringsbedömning där kritiska markkoncentrationer beräknades. I denna bedömning användes uppmätta markkoncentrationer från fältstudien i Peru i två föroreningsscenarier: en med bakgrundshalter i marken (1,1 ng WHO-TEQ kg-1 torrvikt eller 0,001 ppb) och en med en lokal föroreningsnivå motsvarande 69 ng WHO-TEQ kg-1 torrvikt (0,069 ppb). Exponeringsnivåer för två olika populationer undersöktes. Skillnaderna mellan populationerna var relaterade till olika levnadsvillkor för landsbygd respektive stad,

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vilket simulerade förväntade skillnader mellan industrialiserade länder och utvecklingsländer. Beräkningar gjordes i både för vuxna och barn. De

exponeringsvägar som beaktades var intag av jord samt intag av lokalt producerad mat. Eftersom bioackumulationsdata för dl-PCB inte fanns tillgängliga inkluderades inte dl-PCB i detta steg av riskbedömningen.

Det modellerade upptaget av PCDD/F i föda stämde i stort sett väl överens med fältdata från Peru och andra fallstudier. Den största avvikelsen erhölls för ägg, där modellen underskattade upptaget relativt kraftigt. Vid 1,1 ng WHO-TEQ våtvikt i marken (0,001 ppb) överskred aldrig exponeringen från respektive exponeringsväg 10 % av TDI för den mest känsliga populationen (barn i utvecklingsscenariot). Vid 69 ng WHO-TEQ våtvikt i marken (0,069 ppb) erhöll både barn och vuxna i

utvecklingsscenariot en signifikant exponering via alla exponeringsvägar. För flera av exponeringsvägarna var de beräknade doserna för barn nära eller högre än TDI. För intag av jord kan dock risken vara överskattad då det antogs att tillgängligheten för absorption i matsmältningssystemet är 100 %, medan experiment har visat att biotillgängligheten för PCDD/F i jord är begränsad. Kritiska markkoncentrationer, som tillåter en lantlig livsstil för barn med högt intag av lokalt producerad mat men med acceptabla exponeringsnivåer, låg inom 7-25 ng WHO-TEQ kg-1 våtvikt (0,007-0,025 ppb) för PCDD/F. Detta intervall minskar dock till 3-13 ng WHO-TEQ våtvikt (0,003-0,013 ppb) om man antar att 50 % av den totala TEQ exponeringen även kommer från dl-PCB.

Det beräknade intervallet samt intervallets storlek påverkas av flera osäkerheter i modellerings-antagandena, t.ex. i) i vilken omfattning som enskilda exponeringsvägar förekommer tillsammans eller separat, ii) hur stor del av den intagna födan som är lokalt producerad, iii) mängden föda som intas, iv) mängden jord som intas. Eftersom riskbedömningen var baserad på hypotetiska populationer ansågs det mer lämpligt att identifiera ett intervall för kritiska markkoncentrationer snarare än ett enskilt värde.

1.5 Syntes

Med stöd av resultat från flera befintliga studier samt en uppskattning av möjliga exponeringsnivåer för människor kan gränsvärdet på 15 ppb för PCDD/F i avfall anses förknippad med risk för människor. Allvarliga risker uppstår bl.a. om impregnerat trä eller aska tillåts komma in i produktionscykeln för animaliska livsmedel och naturliga betesmarker eller om människor utsätts för direktkontakt med jord/aska.

Det begränsade antalet fallstudier som identifierats kan eventuellt indikera att olämplig hantering av PCDD/F kontaminerat avfall inte är särskilt vanligt. Å andra sidan finns tydliga indikationer på att PCDD/F kontaminerat avfall inte alltid hanteras på ett sätt som gagnar miljön eller människors hälsa. Öppna deponeringsområden och vattendrag i t.ex. Asien och Sydamerika är bevisligen recipienter för dumpning av högkontaminerat avfall. Om sådana aktiviteter har en lokal påverkan på halter av PCDD/F och dl-PCB i miljön eller för människor, tycks hittills inte vara fastställt

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genom fältstudier av tillräcklig omfattning. Resultaten från fältstudierna i detta projekt visade att platser med öppen hantering och förbränning av avfall och aska har förhöjda halter av PCDD/F och dl-PCB, och dessa aktiviteter kan leda till förhöjda halter i omgivande miljön. Eftersom provtagningsplatserna var påverkad av flera källor (t.ex. luftburna emissioner från förbränning inom området) var det inte möjligt att särskilja bidraget från askhanteringen och bidraget från förbränningen.

I riskbedömningen identifierades en kritisk markkoncentration för PCDD/F till 7-25 ng WHO-TEQ kg-1 våtvikt (0,007-0,025 ppb), eller 3-13 ng WHO-TEQ våtvikt (0,003-0,013 ppb) om man antar att dl-PCB kan stå för 50 % av TDI. För barn som lever i en lantlig miljö och vars mat är lokalt producerad motsvarar den kritiska markkoncentrationen en föroreningsnivå som sannolikt inte medför en exponering högre än TDI. Denna bedömning innehåller dock en rad osäkerheter, t.ex. teoretiska antaganden som inte verifierats samt naturliga variationer för de parametrar som ingår. En riskbedömning för hypotetiska populationer kommer alltid att innehålla stora osäkerheter då den är just hypotetisk. För vuxna individer kan intag av jord/aska vara en betydelsefull exponeringsväg i samband med yrkesmässig exponering. Preliminärt har den kritiska halten i fasta matriser för denna exponeringsväg bedömts ligga kring 200-1 000 ng WHO-TEQ kg-1 våtvikt (0.2-1 ppb), men denna bedömning beror bland annat på vilken biotillgänglighet man antar. Här saknas data för askmatriser.

Fältdata visar att dl-PCB ackumuleras i biota i högre utsträckning än PCDD/F. De bidrar också signifikant till TEQ-värdet i livsmedel och ingår i TDI. Det faktum att dl-PCB inte omfattas av föreslaget LPCL för PCDD/F kan bidra till felaktig bedömning av den totala risken som är kopplad till bioackumulation.

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2 Summary

The main focus of the current study was to identify risk scenarios where

polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in wastes are distributed in the environment and transferred to humans via food and other exposure pathways. Two field studies were conducted at sites where wastes and ashes are managed and stored open, one in Thailand and one in Peru. The aim of these studies was to investigate the degree of local environmental impact.

To be able to relate human exposure levels to the suggested LPCL for PCDD/F, a risk assessment was performed using a fate and exposure model (CalTOX), supported by field data from Peru. Additional human exposure from local sources was estimated in relation to inevitable human exposure related to diffuse emissions by exposure calculations.

The aim of the exposure assessment was to establish whether point sources may contribute to human body burdens above the exposure levels that we are inevitably subject to from existing background levels as a result of diffuse pollution.

2.1 Dioxin contaminated waste in current

case studies

We identified four major waste categories as being potentially important in the context of this study:

i) incineration residues, ii) chemical waste, iii) waste wood fractions and

iv) waste from e-waste recycling sites

A limited number of recent case studies are reported for categories i, ii and iv, while case studies for chemical waste mostly are related to historical incidents. Trading and shipping of waste wood fractions may be of special importance since there are recently reported incidents where this waste fraction has contaminated human food chains at animal food production facilities. For ashes, we only identified one study, and it is reported from Britain, where bottom ash and some fly ash from a municipal waste incinerator were recycled as path material in an allotment area. This resulted in elevated concentrations in free-range chicken eggs.

All incidents for waste wood and ash are reported from European countries, but this certainly does not exclude the possibility that that serious risk scenarios exist for developing countries as well. Since these problems can arise in Europe, in spite of well established and robust regulatory frameworks and practices, the probability of similar events occurring in countries with more limited environmental control is even

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higher. However, environmental and food/feed control data from developing countries are often lacking. Since several hazardous pollutants may be present at high levels in waste and open waste dumping sites, some exposed subpopulations (e.g. waste pickers) are at risk for increased exposure. Management of PCDD/F contaminated waste may thus be a serious, but a so far, not well-documented problem. It can be difficult to relate an environmental impact to management of waste in areas where other sources co-exist. In the field studies in Peru and Phuket, consequences of open and unprotected storage of ash could therefore not be investigated separately from the influence of local air emissions.

2.2 Food and exposure levels related to local

sources

Several studies have reported local PCDD/F contamination of soils and waters related to industrial point sources, spills, accidents and other polluting activities. At these sites, elevated exposure levels of humans may occur, often related to consumption of locally produced food. In cases where abiotic media, such as soil or air, are severely polluted, direct exposure of the media, e.g. via ingestion of soil, could also result in high exposure of local inhabitants.

All animal food and feed products contain PCDD/Fs as a result of accumulation from historic and current emissions from various sources. Levels of contamination in food and feed produced near local sources are therefore often related to elevated levels in the environment. This can then result in higher exposure of people residing in vicinity of the source, compared with the exposure levels for the overall population.

A number of studies show that consumption of locally produced free range chickens and eggs is a high risk scenario. Some studies also show that environmental

background concentrations in rural scenarios with no local pollution ‘hotspots’ can cause relatively high PCDD/F levels in free-range eggs. It is difficult to predict concentrations in eggs with high accuracy. The transfer routes between the

environment and chickens are numerous and complex, and are not easily described by models. Factors such as congener composition (relative abundance of congeners) breeding and feeding conditions, soil type and vegetation cover, etc., will affect the bioaccumulation. Results from single case studies can therefore not be used to

establish generic soil-to-egg transfer ratios. Production of other animal food products, such as milk and meat, is also a high risk scenario in the presence of local sources. According to dietary intake studies in different countries, generic population

exposures are often close to, or exceed, the WHO Tolerable Daily Intake (TDI) value. The TDI is an estimate of the average daily intake of a contaminant that can be ingested over a lifetime without appreciable health risk. However, the intake levels differ considerably between different countries. A limited number of studies have dealt with human body burdens and dietary intakes for populations in developing countries. Since food consumption habits and living conditions differ between

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different countries, it may be problematic to use data from industrialised country conditions to express an opinion of the PCDD/F exposure of humans in developing countries.

2.3 Review of the BIPRO assessment

In the risk assessment of PCDD/Fs conducted by a German consultant (BIPRO) for the European Commission it was assumed that the legislated maximum level in commercial eggs is correlated to human health risks based on the tolerable daily intake (TDI). Since the maximum level in food is not based on a human health risk

assessment, compliance of PCDD/Fs levels in eggs (or other food items) with the legislated limits is not an indicator of the risk level and should not be used as a criteria in a risk assessment.

The risk assessment by BIPRO assumes that a PCDD/F concentration of 30 pg WHO-TEQ g-1 fat is acceptable in eggs. By using soil-to-egg transfer factors (so called BTF, biotransfer factors) from two studies, they estimated that the critical PCDD/F

concentration of 30 pg WHO-TEQ g-1 fat in eggs corresponds to soil concentrations of 1 000 ng TEQ kg-1 d.w. (1 ppb).

A consumption of one egg per day is enough to yield a significant contribution to TDI if the eggs contain 3 pg WHO-TEQ g-1 fat or more. In contrast to the conclusions in the BIPRO report, these intake calculations indicate that egg concentrations should not exceed the EU limit value (3 pg WHO-TEQ g-1 fat). A compilation of literature data showed that estimations of soil-to-egg transfer of PCDD/Fs and dl-PCBs are highly variable, and that dl-PCBs are much more available than PCDD/Fs. Considering the large variability of the soil-to-egg transfer factors, selected bio-transfer factors from only a few studies are not representative of generic scenarios. The adopted transfer factor by BIPRO was in the upper range of those calculated from the literature. Thus, there is a risk that BIPRO significantly underestimates the risk for transfer of PCDD/F into eggs at soil concentrations of 1 000 ng TEQ kg-1 d.w. (1 ppb). According to the BTFs calculated from the literature, 3 pg WHO-TEQ g-1 fat in eggs can be reached already at soil concentrations of 1-70 ng TEQ kg-1 d.w. (0.001-0.07 ppb).

The TDI includes exposure both for PCDD/Fs and dl-PCBs, and both compound groups may be transferred from solid waste matrices into human food chains, even though dl-PCBs are more available than PCDD/Fs. Since BIPRO did not consider the contribution from dl-PCBs in waste to the food chain transfer, their assessment does not reflect the total risk.

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2.4 The exposure assessment

The exposure assessment conducted within the current study was based on two contamination scenarios: one background scenario (1 ng WHO-TEQ kg-1 w.w. or 0.001 ppb in the soil) and one local contamination scenario (70 ng WHO-TEQ kg-1 w.w. or 0.07 ppb in the soil). Exposure levels of two different populations were investigated, reflecting different living conditions for rural/urban life styles and simulated expected differences between industrialised and developing countries. Each population consisted of adults and young children. Exposure pathways considered were ingestion of soil and locally produced food. Because of limited access to important bioaccumulation data needed for the model calculation, dl-PCBs were not included in the exposure assessment at this stage.

The modelled accumulation in food was generally in good agreement with field data from Peru or other case studies. The most distinctive disagreement was for

concentrations in eggs, where the model underestimated the risk. At 1.1 ng WHO-TEQ kg-1 w.w. (0.001 ppb) in soil, the exposure levels of single exposure routes never exceeded 10% of TDI for the most sensitive target population (children in the

Development setting). At 69 ng WHO-TEQ kg-1 w.w. (0.069 ppb) in soil, children and adults in the Development setting received significant exposure levels via all the exposure routes. For most of the routes, single doses of the children were close to or above the TDI. For ingestion of soil, however, the risk may be over-estimated since the availability for absorption in the digestive tract was assumed to be 100%, while experimental data have shown that the bioavailability is significantly reduced for pollutants present in soil matrices. Critical soil concentrations, which allow a rural life style with high ingestion rates of locally produced food but acceptable exposure levels in relation to TDI, were identified in the range 7-25 ng WHO-TEQ kg-1 w.w. (0.007-0.025 ppb) soil for PCDD/F. The range is reduced to 3-13 ng WHO-TEQ kg-1 d.w. (0.003-0.013) if it is assumed that dl-PCBs will add to 50% of the total TEQ exposure. The precision of the range is affected by several uncertainties in the modelling

assumptions, e.g. i) to what extent the exposure routes will exist simultaneously or alone, ii) the amount of ingested food that is locally produced, iii) food ingestion rates, and iv) the amount of ingested soil. Since the assessment were based on hypothetical populations, it was considered as more reasonable to identify an interval of critical soil concentrations, rather than one single value.

2.5 Synthesis

Supported by results from existing case studies and the human exposure assessment, the suggested limit of 15 ppb for PCDD/Fs in waste is considered to be associated with risks for humans. There are e.g. risks if impregnated wood or ash is introduced in the production of animal food items or natural pastures, or if humans are subject to direct contact with soil/ash.

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The limited number of existing case studies may indicate that improper management of PCDD/F waste is uncommon. On the other hand, there are indications that PCDD/F contaminated waste is not always managed having protection of the environment and human health in mind. Open waste dump sites and rivers in e.g. Asia and South America are potential targets for dumping of highly contaminated waste. If such activities do have an impact on local environmental PCDD/F or dl-PCB

concentrations or human exposure levels, it is, so far, not well investigated. The minor field studies in Peru and Thailand confirmed that highly contaminated ashes are stored on open ground at sites where the waste is produced. The results indicated that such sites constitute PCDD/F and PCB pollution hot spots that may affect the surroundings by wind-blown distribution of ashes. Our field study did, however, not allow apportionment between contamination from ash residues and local air emissions from the recycling activities.

In the risk assessment, a critical soil concentration of 7-25 ng WHO-TEQ kg-1 w.w. (0.007-0.025 ppb), or 3-13 ng WHO-TEQ kg-1 w.w. (0.003-0.013 ppb) if one assumes that dl-PCB contribute to 50% of the TDI, was identified. For children in rural setting and where the food is locally produced, the critical soil concentration corresponds to a level where the exposure is not likely to exceed TDI. The assessment includes a number of uncertainties, e.g. some of the assumptions have not been verified and the natural variability of the parameters was not taken into account. A risk assessment which is made for hypothetical populations will always suffer from a large degree of uncertainty. For adults, ingestion of soil and ash can constitute an important exposure route in occupational exposure scenarios. A critical solid matrices concentration has preliminary been assessed to 200-1 000 ng WHO-TEQ kg-1 w.w. (0.2-1 ppb) for this exposure route, depending on assumed internal bioaccessibility. Such data is lacking for ash matrices.

Field data from several scientific studies show that dl-PCBs accumulate to a higher extent than PCDD/F in biota. Dl-PCBs contribute significantly to the total TEQ in food and risks can be assessed by comparing daily intake to the TDI for PCDD/Fs and dl-PCBs. Since dl-PCBs are not included in the suggested LPCL for PCDD/F, the total risk associated to exposure of PCDD/F and dl-PCB contaminated waste can be

underestimated.

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3 Background

The production, use and release of persistent organic pollutants (POPs) are dealt with by the Stockholm Convention, which aims to reduce and eliminate the flows of these substances in the environment. PCDD/Fs and PCBs are two substance groups that are categorised as POPs in terms of persistence, environmental behaviour and toxicology. In order to classify and manage waste products in an environmentally sound manner, a suggested maximum level of 15 µg TEQ kg-1 (15 ppb) for PCDD/F in waste was first proposed by the Basel convention, and was later adopted by EU (BIPRO, 2005). The corresponding level for ∑PCB6 is 50 mg kg-1 (50 ppm). These levels are commonly referred to as the Low POP Content Limits (LPCL). Some PCDD/F contaminated waste products may be recycled in the society, and contaminants in the waste can therefore be distributed into the environment.

There is an increased concern of environmental problems caused by uncontrolled dispose and recycling of waste and waste products. Urbanisation and industrial growth in developing countries stimulates the production of hazardous waste, and proper disposal strategies are needed to reduce environmental harm and human health risks in these countries (Omran & Gavrilescu, 2008). While many industrialised countries have an environmentally sound management of hazardous waste, developing countries lack much of the financial and political resources needed to treat the waste in a proper manner or to control possible health impacts from hazardous waste (Sonak et al., 2008; Yousif & Scott, 2007; Mbuligwe & Kaseva, 2006). These countries face also problems related to the absence of sanitary landfills, limited public knowledge about proper waste management practices and increasing illegal dumping. In some cases, hazardous waste is neither treated nor separated from the non-hazardous waste fraction, and the dump sites are neither lined nor covered. Local authorities do not necessarily consider environmental impacts of new or existing dump sites. Thus, waste deposits can be allocated to areas without considering the potential transport of hazardous pollutants, and monitoring and safeties practices such as covering and fences are neglected. Inspection of waste before dumping is not always occurring, and illegal dumping of toxic chemicals is not uncommon. Regulation of maximum levels of PCDD/Fs and dioxin-like compounds in waste is therefore important, both at national and international scales, in order to prevent further distribution of POPs in the environment and to protect human health.

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4 Dioxins

The chemical substances covered in this report are polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dl-PCB). PCDDs and PCDFs are usually treated as one compound group with the acronym PCDD/Fs and commonly referred to as dioxins. In this report, only 2,3,7,8-substituted congeners were considered.

A number of PCBs share the same toxic mode of action as 2,3,7,8-substituted

PCDD/Fs. These substances are called dioxin-like PCBs (dl-PCBs) or co-planar PCBs. Dl-PCBs consist of 12 non-ortho and mono-ortho substituted PCBs (PCBs 77, 81, 105, 114, 118, 123 126, 156, 157, 167, 169, 189; numbering according to IUPAC). 2,3,7,8-substituted PCDD/Fs and dl-PCBs have been assigned toxicological

equivalence factors (TEFs) according to a scheme that originally was developed for PCDD/Fs (Van den Berg et al., 2006). TEFs are used to calculate toxic equivalence concentrations (TEQs) from analytical concentrations of single congeners. The total toxicity of a mixture of congeners is the sum of products of the analytical congener concentrations and their TEFs. There is no consistency of reported TEQ units in the literature since different TEF schemes have been developed (I-TEF, WHO-TEF, etc). When citing data, originally reported TEQ units have usually been cited. However, in some data compilations, it was not convenient to keep the original TEQ units and the generic expression “TEQ” was used instead. Empirical data from the field studies are reported as WHO-TEQ, following the TEF scheme from 2005 as presented in Table 1.

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Table 1. TEF scheme according to WHO (Van den Berg et al., 2006). Congener WHO-TEF 2005 2,3,7,8-TCDD 1 1,2,3,7,8-PeCDD 1 1,2,3,4,7,8-HxCDD 0.1 1,2,3,6,7,8-HxCDD 0.1 1,2,3,7,8,9-HxCDD 0.1 1,2,3,4,6,7,8-HpCDD 0.01 OCDD 0.0003 2,3,7,8 -TeCDF 0.1 1,2,3,7,8 -PeCDF 0.03 2,3,4,7,8 -PeCDF 0.3 1,2,3,4,7,8 -HxCDF 0.1 1,2,3,6,7,8 -HxCDF 0.1 2,3,4,6,7,8-HxCDF 0.1 1,2,3,7,8,9-HxCDF 0.1 1,2,3,4,6,7,8 -HpCDF 0.01 1,2,3,4,7,8,9-HpCDF 0.01 OCDF 0.0003 PCB #77 0.0001 PCB #81 0.0003 PCB #105 0.00003 PCB #114 0.00003 PCB #118 0.00003 PCB #123 0.00003 PCB #126 0.1 PCB #156 0.00003 PCB #157 0.00003 PCB #167 0.00003 PCB #169 0.03 PCB #189 0.00003

So far, Low POP Content Limits are only suggested for PCDD/Fs and the sum of seven PCBs (∑PCB7), while dl-PCBs are not yet suggested to be regulated. Because of their dioxin-like properties, however, they should ultimately be included in the LPCL for PCDD/Fs, since human health risks depend on both compound groups. This is also the reason to why both PCDD/Fs and dl-PCBs were addressed in this report. Two different concentration units for solid matrices are used in the cited literature. The units “ppb” and “ppm” are applied for the Low POP Content Limits, while universal units such as “ng kg-1” or “pg g-1” are used for empirical data in the open literature. The units are translated into each other according to

ppb = parts per billion = µg kg-1 (or 1000 ng kg-1) = ng g-1 ppm = parts per million = mg kg-1= µg g-1

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5 Dioxin

contaminated

waste

5.1 Waste

categories

Dioxin contaminated wastes are generated by different activities in the society and consist mainly of solid matrices. The industrial sector is the major producer of waste, and major amounts origin from municipal waste incineration (MSWI), power

production, and metallurgical and steel alloy industries. A more comprehensive compilation of sources and dioxin waste flows is presented in BIPRO (2005). It was beyond the scope of this study to present a full review of dioxin levels in different waste fractions, but a selection of existing data is presented below to

illustrate the contamination levels of different waste categories that were confirmed to be of importance in the context of this study:

i) residues from thermal processes,

ii) impregnated wood and waste wood litter, iii) chemical waste, and

iv) residues from e-waste recycling

These waste fractions are considered as important in relation to the produced amounts and known contamination levels (categories i-iii), or from case studies of sites were management/recycling of PCDD/F contaminated waste has harmed the environment or human food chains (categories i-iv).

A thorough literature search for case studies and incidents that exemplifies environmental harm or human health risks caused by improper management of PCDD/F contaminated waste was conducted, but only a few relevant studies were found. These are presented in the following paragraphs. On the contrary, there are a number of studies that report upon national food contamination incidents, where human food chains were severely contaminated by PCBs or PCDD/Fs (Hoogenboom et al., 2004). Many of these cases were probably caused by illegal actions, accidents or unawareness of PCDD/F or PCB residue levels in products and ingredients that later were introduced into feed and food chains. However, the incidents were often tracked to small producers, which in the end had a large and negative financial impact on affected feed and food markets (Fürst, P., Plenary lecture Dioxin Conference 2009). The cases illustrate the ease in which food chains becomes negatively affected if materials are contaminated by processes in the modern society.

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5.2 Residues from thermal processes

5.2.1 Concentrations of pollutants

Incineration generates different types of solid residues, such as fly ashes, filter dusts, bottom ash and boiler ash. Major producers include municipal waste incineration plants (MSWI), power plants, metallurgical and chemical industries. Residues from thermal processes are also generated from metal recycling. These residues contain various levels of PCDD/Fs and dl-PCBs. Fly ash measurements have been numerous, while MSWI bottom ash and boiler ash are less frequently investigated. In Table 2, data from a number of references are compiled to illustrate expected PCDD/F levels. However, the compilation covers only a selection of studies and matrices.

Table 2. Concentrations (ng TEQ kg-1) of PCDD/Fs in different incineration residues.

Waste type PCDD/F

(ng TEQkg-1)

Country Reference Fly ash, industrial & medical

refuse

8 500-67 500 Colombia Aristizabal et al., 2008

Fly ash, power production 2.2-190 Mauritius Yive & Tiroumalechetty, 2008 Filter dust, galvanising plant 127-8 075 Spain Martinez et al., 2008

Ash, Waelz process 103 000 Taiwan Chi et al., 2008 Fly ash, secondary steel plant 1 899 Thailand UNEP, 2001 Bottom ash, MSWI 5-10 Thailand "

Fly ash, MSWI 228-686 Thailand "

Bottom ash, MSWI 0.2-245a various Vehlow et al., 2006

Boiler ash, MSWI 0.3-400b various "

Fly ash, MSWI 120-41 4000a various "

Bottom ash, MSWI 0.1-200 Sweden Svenska Renhållningsverks-föreningen, 2001

Fly ash, MSWI 140-18 000 Sweden "

Fly ash, bio fuels 120-270 Sweden Oehme & Muller, 1995 Bottom ash, bio fuels 0.2-1.1 Sweden "

asamples from 1990-2004; bsamples from 1990-1999

The expected range of PCDD/F concentrations in bottom ash from modern MSWI facilities is 1-30 ng TEQ kg-1. For recently produced fly ashes, the range is 100-10 000 ng TEQ kg-1 (Vehlow et al., 2006). During the past decade, PCDD/F

concentrations in fly ash have decreased (Vehlow et al., 2006).

The fuel type is of major importance for the final levels in the residues. Fly ash and bottom ash from bio fuel combustion usually contain lower levels (<300 ng TEQ kg-1; Table 2), than ashes from MSWI. However, mixing with PCDD/F contaminated wood fractions may elevate the levels by orders of magnitude (Oehme & Muller, 1995). Limited data exist for PCB levels in MSWI solid residues (Vehlow et al., 2006). When measured, dl-PCBs are generally not reported separately from other PCBs. Thus, it is

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difficult to get good estimates of general levels in incineration residues. In the study by Vehlow and co-authors (2006), dl-PCBs contributed by 2-7% of the total TEQ in MSWI bottom ash, and by <1-10 % in MSWI fly ash. Other studies have reported a TEQ fraction of 1% for dl-PCBs in fly ash (Sakurai et al., 2003).

Accidental fires will also result in residues contaminated with PCDD/Fs. Swedish experiments with e-waste and car tyre fires resulted in waste that contained 11-2 100 ng I-TEQ kg-1 (SP Swedish National Testing and Research Institute, 2005). The highest PCDD/F level was found in e-waste fire residues, while dl-PCBs were not analysed.

5.2.2 Case studies

A recent publication by Mari et al. (2009) reported on the impact on environmental levels and human health from a hazardous waste landfill in Catalonia (Spain) that receives PCDD/F contaminated residues. The landfill site operates according to national regulations, and waste management practices follows principles set by EU. The authors found a slight increase of PCDD/F concentrations in air and soil at the landfill, but in general terms, the concentrations were low and the human health assessment indicated no risk for local residents exposed to air or soil. The soil concentrations were 1.5 and 2.1 ng WHO-TEQ kg-1 d.w. However, this landfill is sealed and protected and is not representative of open landfills or other non-regulated waste sites.

In the UK, there is one relevant case study (Pless-Mulloli et al., 2001) that illustrates how dioxin contaminated incineration residues will contaminate the environment and human food chains if the management and recycling practices are not fully controlled. During a period of 5 years (1994-1999), 2 000 tons of ash was recycled at 51 sites across Newcastle.

There are different types of incineration waste that may contain PCDD/Fs or dl-PCBs.

It seems that expected ranges in most waste products will fall below the suggested LPCL for PCDD/F. For dl-PCBs, knowledge about

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One of the sites consisted of allotment areas where animals (hen, ducks, pigeons and horses) also were raised. Ash samples from foot paths contained up to 9 500 ng I-TEQ kg-1, which is below the suggested LPCL of 15 000 ng TEQ kg-1, while the highest recorded soil concentration was 272 ng I-TEQ kg-1. Eggs from the allotments

contained 0.4-56 pg I-TEQ g-1 fat, and the congener distribution patterns were similar to that of ash. It was concluded that PCDD/Fs had been transferred into chicken eggs, even when the animals did not have direct access to the contaminated footpaths. In the risk assessment, it was recommended that poultry and egg production should be restricted until the ash was removed.

Other studies indicate that management of ashes might be a source of PCDD/Fs in local environments in poor countries, and that some populations might be at risk for elevated exposure, even though no cases studies are reported. In some countries, PCDD/F levels in incineration ashes is not regulated at all, and the residues are often mixed with household waste and disposed of in municipal solid waste landfills without previous treatment or protection of human health (Aristizabal et al., 2008). Elevated exposure to hazardous pollutant is therefore possible for people scavenging the landfills for recyclable material. The field sampling at the waste site Zapallal (Peru) that was performed within the current project showed that levels of PCDD/Fs in ash stored on open ground were close to the suggested LPCL of 15 ppb (Chapter 9). The final fate of the contaminated residues is not known, but according to a

pre-investigation of the area by local NGOs, a nearby river is used for dumping of waste. In Europe, local NGOs have reported upon dumping of ash-like residues of unknown, European origin in Belaruchi (Belarus, Figure 1). The material was dumped on open, unprotected ground, and the residues contained approximately 1 000 ng TEQ kg-1 (1 ppb; personal communication J. Petrlik, Arnika, Czech Republic).

The egg concentrations in the Newcastle case correspond to 0.04-5.6 pg I-TEQ g-1 fresh

weight (assuming a fat content of 10% in whole eggs).

A daily consumption of one Newcastle egg (60 g) per day equals a human dose of 0.04 to 5.6 pg I-TEQ kg-1 b.w. and day (assuming a bodyweight of 60 kg).

The recommended tolerable daily intake (TDI) for PCDD/Fs and dl-PCBs is 2 pg TEQ kg-1 b.w.

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Figure 1. Dumping of PCDD/F contaminated residues in Belaruchi, Belarus (J. Petrlik, Arnika).

Open dumping of POP-contaminated waste can also affect wildlife (Watanabe et al., 2005). Uncontrolled management strategies will therefore result in that toxic

substances are transferred into the environment with reduced possibilities to detect or measure impacts on the environment or human health.

Regardless if dumping of PCDD/F contaminated ashes is a legal or illegal action, it will increase the environmental hazard at open dump sites. These areas are already known to contain elevated levels of hazardous compounds, such as DDT, PCBs and HCH (Minh et al., 2006). Dump sites may also contain elevated concentrations of PCDD/F due to e.g. open burning and recycling activities (Minh et al., 2003; Table 3). Dumping of PCDD/F contaminated waste from other activities will therefore become an additional source.

Table 3. Reported PCDD/F soil concentrations (ng WHO-TEQ kg-1 d.w.) from open dump sites and control sites in Asian countries (Minh et al., 2003).

Philippines Cambodia India Vietnam-Hanoi

Vietnam- Ho Chi Minh Dump site 400-630 1.4-1 700 9.9-200 0.4-850 0.02-4.4

Control site - 0.031-4.5 0.05-0.34 1.0 0.36-1.2

Other risk scenarios for solid residues from thermal processes are related to recycling in e.g. geotechnical applications, construction materials and agriculture (Ferreira et al., 2003). However, few investigations have focused on the environmental impact with respect to organic contaminants for these recycling options. At the same time, there are known examples where town refuse waste ash has been used as fertiliser to increase the fertility of soil (Pasquini, 2006).

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Residues from electric arc furnaces and ashes containing high levels of zinc can be recycled in industrial processes, such as the Waelz process, to extract the metals. Since PCDD/Fs are regenerated in the process, the recycling may result in high emissions to air if the air pollution control devices are inefficient (Chi et al., 2006). Chi and co-authors demonstrated that 560 ng TEQ kg-1 recycled ash was emitted from one facility. This recycling option will therefore result in large emissions to air and highly contaminated solid waste residues are generated (Chi et al., 2008; Table 2)

5.3

Impregnated wood and waste wood litter

5.3.1 Concentrations of pollutants

PCDD/Fs are unintentionally formed during the production of e.g. wood impregnation chemicals (such as Ky-5, Dowicide G and other chlorophenol based agents). The production of these pesticides has ceased, but CP treated wood may still contain high levels of PCDD/Fs. In Table 4, wood and wood litter TEQ concentrations reported in the open literature are compiled.

Table 4. Reported PCDD/F and dl-PCB concentrations (ng TEQ kg-1) in different wood fractions.

Waste type PCDD/F dl-PCB Country Reference

Wood at animal prod. facilities

n.d.-91 620 - USA Huwe et al., 2004

Sleepers 21 000 0.93 Japan Asari et al., 2004 Waste wood chips 0.94 0.51 " "

Untreated wood 0.006 0.30 " "

Litter 0-0.86 0.19-240 " "

PCP treated wood 11-315 000 - - Fries et al., 2002 Impregnated wood 67- 38 000 - various SEPA, 2009 Wood litter 50a - Italy Brambilla et al., 2009

n.d.; not detected, a the concentration was published as 50 000 ng WHO-TEQ kg-1 but was corrected

to 50 ng WHO-TEQ kg-1 after correspondence with the author; PCP: penta-chlorophenol

Even though the TEQs are mostly related to PCDD/Fs, dl-PCBs can in some cases contribute significantly as well. However, not all studies have included dl-PCBs in the

The management of PCDD/F contaminated waste is poorly regulated in some countries. Open, unprotected storage and dumping practices in poor countries may be risk scenarios with limited possibilities to detect and measure impacts

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Maximum levels are legislated limit values for contaminants in food (see also Table 4). PCDD/F in eggs and egg products:

3 pg WHO-TEQ g-1 fat

PCDD/F and dl-PCB in eggs and egg products:

6 pg WHO-TEQ g-1 fat

PCDD/F in milk and dairy products:

3 pg WHO-TEQ g-1 fat

PCDD/F and dl-PCB in milk and dairy products: 6 pg WHO-TEQ g-1 fat

analysis. The range of reported concentrations is large, but it is obvious that waste wood fractions will fall above and below the currently suggested LPCL.

5.3.2 Case studies

As long as CP treated wood is in use, demolition of old wood constructions may result in highly contaminated waste wood fractions. Recent studies have shown that waste wood fractions may enter the human food chain via animal food production facilities (Brambilla et al., 2009; Diletti et al., 2005; Asari et al., 2004), and that shipping of

contaminated wood between countries is a risk scenario.

Two case studies report serious contamination of chicken eggs by penta-chlorophenol (PCP) contaminated wood litter (Brambilla et al., 2009; Diletti et al., 2005). Both incidents took place in Italy. In one study, the wood litter contained 50 ng WHO-TEQ kg-1, resulting in mean chicken egg

concentrations of 46 pg WHO-TEQ g-1 fat (Brambilla et al., 2009; the published wood litter concentration of 50 000 ng WHO-TEQ kg-1 has here been corrected to 50 ng WHO-TEQ kg-1 after correspondence with the author). Brambilla and co-authors point also out that there is no legislation to prevent exposure of food-producing animals to bioaccumulative substances via materials, such as barns, stables or litter. In the other study, contaminated wood litter (50.8 ng WHO-TEQ kg-1) and wood shavings (40.1 ng WHO-TEQ kg-1) was used at the farm (Diletti et al., 2005). Chicken egg and chicken meat contained PCDD/Fs at levels significantly exceeding legislated maximum levels for food stuffs (eggs: 33 and 88 pg WHO-TEQ g-1 fat; meat: 45.2 pg WHO-TEQ g-1 fat).

Recent incidents in Europe show that recycling of PCDD/F contaminated wood is a risk scenario for animal food production facilities. Waste wood concentrations were far below the suggested limit of 15 ppb for PCDD/F.

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5.4 Chemical

waste

5.4.1 Concentrations of pollutants

The use and production of chlorinated pesticides and chemicals have polluted the environment with PCDD/Fs in several countries (Holt et al., 2010, Weber et al., 2008). Table 5 summarises concentrations of PCDD/Fs and dl-PCBs in some chemical products.

Table 5. Reported PCDD/F concentrations (ng TEQ kg-1) of technical formulations.

Product PCDD/F Country Reference

PCP 140 000-5 400 000 Japan Masunaga et al., 2001

CNP 2 600-10 000 000 " "

Chloranil 20-16 300 China Zhu et al., 2008; Zhang et al., 2002

Pentachlorophenol (PCP) and chlornitrofen (CNP) products may contain extremely high concentrations of PCDD/Fs. High levels may also be found in dye ingredients, e.g. chloranil, that are currently used in textiles, plastics and paints (Zhang et al. 2002; Zhu et al. 2008). The contamination levels seem to depend on the production date, since lower levels are often found in more recently produced chemicals (Masunaga et al., 2001; Zhu et al., 2008; Zhang et al., 2002).

Since PCDD/Fs are detected in chemical formulations that are currently in use (Holt et al., 2010; Zhang et al., 2002; Zhu et al., 2008), waste from the production may also contain levels that are of concern. There is, however, limited data on PCDD/Fs concentrations of production waste categories in the open literature. Historically, the chemical industry has a large record of PCDD/F contamination incidents related to production of chemicals and handling of waste (Weber et al., 2008). Due to the high production volumes of the chemical industry in e.g. China, Zhu et al. (2008) addressed their importance as a relevant PCDD/F source.

The problems related to pollutants in chemical waste are complex, since chemical recycling and remediation processes may generate emissions of other toxic

compounds than the original ones (Braga et al., 2002). The toxicity of chemical waste is also dependent on mixtures of pollutants, and not only to PCDD/Fs. Chemical waste often consists of technical chemical formulations such as pesticides. The presence of a mixture of hazardous pollutants may result in that this waste category can be classified as a POP-waste based on other criteria than the abundance of PCDD/Fs. Chemical waste has been recognised as a growing environmental and human health risk problem in poor countries, as well as in industrialised ones (Holt et al., 2010).

5.4.2 Case studies

Identified case studies related to management of PCDD/F contaminated chemical-waste are mostly related to historical incidents (Asmus et al., 2008; Lee et al., 2006a

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and b; Wu et al., 2001; Isosaari et al., 2000). The cases are characterised by large emissions of chemicals or production wastes to soil or waters. The magnitude of the contamination have resulted in severely contaminated food chains and elevated exposure of humans (Asmus et al., 2008; Lee et al., 2006a; Braga et al., 2002). No reports on recent incidents were found.

5.5 E-waste

recycling

5.5.1 Concentrations of pollutants

An ongoing formation source of PCDD/Fs is the recycling of e-waste in developing countries (Sepúlveda et al., 2009; Wong et al 2007; Leung et al 2007, Gullett et al., 2007). Besides of air emissions, incineration and recycling residues may contain high levels of organic pollutants. In

Table 6, PCDD/F levels in different types of residues from the e-waste megasite Guiyu (China) are compiled. Since dl-PCBs were not included in the measurements, total TEQ levels in the waste fractions are most likely even higher.

Table 1. Reported PCDD/F levels (ng TEQ kg-1) in waste products from e-waste recycling in

China.

Waste type PCDD/F Reference

Ash 5 700 Zhu et al., 2008

Electronic shredder waste 66.9 Ma et al., 2008 Acid leachate 203-1 100 Leung et al., 2008 Cable wiring and plastic combustion

residues

84-174 "

Ash 155-14 400 Luksemburg et al., 2002

5.5.2 Case studies

Even though e-waste sites are known for on-going contamination of the environment, few measurements of PCDD/F contamination related to management of residues from the recycling activities have been reported (Sepúlveda et al., 2009). Most concern has been raised about air emissions, and less focus has so far been paid to the management of the solid/liquid residues. However, in one study from the mega-site Guiyu, it was reported that PCDD/F polluted ash from the e-waste site at had been dumped in the adjacent Lianjing River (Luksemburg et al., 2002). Sediment samples from the dumping site showed extremely high contamination levels (up to 35 200 ng WHO-TEQ kg-1 d.w.). At this site, the residents used water from the river for washing clothes and cleaning cookery utensils. Sediment samples 20 and 50 km downstream the e-waste site did, however, not contain elevated levels, which was tentatively explained by the low flow of the river.

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E-waste recycling activities are known as on-going sources for formation of PCDD/Fs. Residues from the recycling are known to be contaminated with

PCDD/Fs. However, limited data exist, and dl-PCBs have not been investigated. Dumping of PCDD/F contaminated e-waste residues in the

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6 Human

exposure

There is a general consensus that humans are mainly exposed to PCDD/Fs and dl-PCBs via the diet (Mato et al., 2007; European Commission, 1999). Most important are ingestion of food of animal origin, such as meat, dairy products, eggs and fat fish. In pristine environments, the background concentrations of both PCDD/Fs and dl-PCBs are low and exposure via ingestion of soil and water or inhalation of air is insignificant.

Tolerable weekly intakes (TWI) of PCDD/Fs and dl-PCBs for humans stand for a long-term weekly intake with no risk of negative effects of human health. The TWI recommended by the Scientific Committee on Food of the European Commission is currently set to 14 pg TEQ kg-1 b.w. week-1 (SCF, 2000). This recommendation is often expressed as a tolerable daily intake (TDI) of 2 pg TEQ kg-1 b.w. day-1. In 2000, WHO came up with a TDI of 1-4 pg TEQ kg-1 b.w. day-1, where the lowest level is a long term goal (WHO, 2000). The TDI is often used to evaluate results from dietary intake studies of different populations.

6.1 Exposure via dietary intake

Dietary intake studies are used to estimate human exposure of pollutants from ingestion of food based on food concentration and food ingestion data. A compilation of data from dietary exposure studies for PCDD/Fs and dl-PCBs from different countries are presented in Table 7. The compilation should not be considered as complete, but illustrates the variation of human exposure levels for different age classes and countries.

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Table 2. Reported estimations of dietary intake of PCDD/Fs and dl-PCBs (pg TEQ kg-1 b.w.

day-1) for human populations.

Country Age Mean/median 90th or 95th

percentile

Reference

Netherlands 40 1.1 1.7 Baars et al., 2004

" 10 1.5 2.3 "

" 2 2.8 4.4 "

Italy 13-94 2.28 - Fattore et al., 2006

" 7-12 3.37 - "

" 0-6 5.34 - "

Finland adult 1.5 - Kiviranta et al, 2004

Sweden <10 2.7-4.5b 4.6-9.3 Bergkvist et al., 2008

" 11-24 1.5-2.1b 3.3-5.1 "

China - 1.4 - Zhang et al., 2008

China 18-45 0.15-0.96 - Li et al., 2007

Japan - 1.52 or 1.78a 2.91

Japan 17-72 1.06/0.79 - Arisawa et al., 2008

USA 0-1 42.0 - Schecter et al., 2001

" 1-11 6.3/6.1c - "

" 12-19 3.5/2.7 c - "

" 20-79 2.4/2.2 c - "

" 80+ 1.8/2.0 c - "

Egypt - 6.04-6.68 - Loutfy et al., 2006

aestimated by deterministic or probabilistic approach; bdifferent genders and age classes; cmales and

females, respectively;

As illustrated by Table 7, the estimated dietary intake levels differ between different countries. Some of the variation is likely related to differences in the applied

methodology of the investigations, but more important factors are probably dietary habits, national and local contamination levels of food and geographical location of the populations (Arisawa et al., 2008; Chen et al., 2003; Undemann et al., 2009)

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Available data needed for estimation of dietary intake exposure and human body burdens of environmental pollutants in developing countries and remote areas are limited (Linderholm et al., 2009; Sun et al., 2005; Sun et al., 2006). Significant

uncertainties will therefore remain about the exposure levels of general populations and subpopulations in these areas, but might be reduced by the global POPs monitoring program related to the Stockholm Convention and the ongoing global human milk study. The study by Loutfy et al. (2006) indicates that the exposure levels of general populations in

developing countries may exceed the current exposure of the populations in industrialised countries. In contrast, low exposure levels have been estimated for populations in remote areas of e.g. China (Sun et al., 2005). In an international screening study of POPs in butter, it was concluded that butter from Asia, America and South African regions were less contaminated than butter from Europe, which indicate that the overall exposure level is lower in these countries (Santillo et al., 2003). However, the authors of this study stated that limited food concentration data from these regions exist, and the representativeness of existing samples for each region could not be guaranteed.

Environmental and human living conditions are not the same in developing countries as in industrialised ones, and local sources such as waste dump sites and back-yard burning, may add to the total exposure, directly or indirectly (Kunisue et al., 2004). Since many poor people depend on food from the local environment, they are more vulnerable for contamination of food chains via local sources. In contrast,

industrialised populations buy most of their food via groceries, where the food is commercially produced and controlled by national and international legislations. Dietary habits might also differ between urban and rural populations.

6.2 Exposure routes near local pollution

sources

Local PCDD/F sources may affect biotic and abiotic exposure media via emissions to air, water or soil. Direct exposure via these media contributes in general to no more than a few percent of the total dietary exposure. In local contamination scenarios, contaminated local food chains are often identified as the main risk scenario (Kao et al., 2007; Pirard et al., 2005; Pless-Mulloli et al., 2005). However, there are cases when local emissions have caused incremental human exposure by contact with soil and air.

Little is known about dietary exposure levels of populations in developing countries. There are a large number of factors that contribute to the dietary exposure levels. Thus, it is not possible to extract data for a population in a specific region and then apply these data for populations in other parts of the world.

A compilation of international data shows that many populations are exposed for dioxins and dioxin-like PCBs at doses near or above the tolerable daily intake (TDI) of 2 pg WHO-TEQ kg-1 b.w. and day.

Figure

Table 1. TEF scheme according to WHO (Van den Berg et al., 2006).  Congener                                                WHO-TEF 2005  2,3,7,8-TCDD 1  1,2,3,7,8-PeCDD 1  1,2,3,4,7,8-HxCDD 0.1  1,2,3,6,7,8-HxCDD 0.1  1,2,3,7,8,9-HxCDD 0.1  1,2,3,4,6,7,8-H
Table 2. Concentrations (ng TEQ kg-1) of PCDD/Fs in different incineration residues.
Table 4. Reported PCDD/F and dl-PCB concentrations (ng TEQ kg-1) in different wood  fractions
Table 5. Reported PCDD/F concentrations (ng TEQ kg-1) of technical formulations.
+7

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