research for RIJKSINSTITUUT VOOR VOLKSGEZONDHEID EN MILIEU man and environment NATIONAL INSTITUTE OF PUBLIC HEALTH AND THE ENVIRONMENT RIVM report 711701 025 Re-evaluation of human-toxicological maxi- mum permissible risk levels A.J. Baars, R.M.C. Theelen, P.J.C.M. Janssen, J.M. Hesse, M.E. van Apeldoorn, M.C.M. Meijerink, L. Verdam, M.J. Zeilmaker March 2001 This investigation has been performed as part of RIVM project 711701, “Risk in relation to Soil Quality”, by order and for the account of the Directorate-General for Environmental Protection, Directorate for Soil, within the framework of project 711701. RIVM, P.O. Box 1, 3720 BA Bilthoven, telephone: 31 - 30 - 274 91 11; telefax: 31 - 30 - 274 29 71 page 2 of 297 RIVM report 711701 025 Abstract Soil Intervention Values are generic soil quality standards based on potential risks to humans and ecosystems. They are used to determine whether or not contaminated soils meet the crite- ria for “serious soil contamination” of the Dutch Soil Protection Act. Regarding the potential risks to humans, MPR values quantifying the human-toxicological risk limits (i.e., tolerable daily intake, tolerable concentration in air, oral cancer risk and/or inhalation cancer risk) for some 50 chemicals and chemical classes were derived in the period 1991-1993. These MPRs have now been updated. Together the compounds comprise 12 met- als (including cadmium, lead and mercury), 10 aromatic compounds (including the polycyclic aromatics), 13 chlorinated hydrocarbons (including dioxins and polychlorinated biphenyls), 6 pesticides (including DDT and the drins) and 7 other compounds including cyanides and total petroleum hydrocarbons. For each compound or compound class a toxicity profile has been compiled, consisting of a concise summary of the available toxicity data, information on background exposure, and a survey of existing limit values derived by other organisations. Each profile leads to an updated MPR for the compound (or class of compounds) in question. RIVM report 711701 025 page 3 of 297 Preface This investigation has been performed as part of RIVM project 711701, “Risk in relation to Soil Quality”, by account of The Ministry of Housing Physical Planning and the Environ- ment, Directorate General for the Environment (DGM), Directorate of Soil Protection, and comprises the full revision of human-toxicological Maximum Permissible Risk levels as was summarised in Chapter 4 of RIVM report 711701 023: “Technical evaluation of the Interven- tion Values for soil/sediment and groundwater” (December 2000). page 4 of 297 RIVM report 711701 025 Contents Samenvatting 6 Summary 7 1. Introduction 8 2. General procedure 9 2.1. Definitions 9 2.2. Threshold versus non-threshold approach 9 2.3. Excess lifetime cancer risk 9 2.4. Tolerable daily intake (oral and inhalation) 9 2.5. Deriving a MPR 10 2.6. Uncertainty factors 10 2.7. Route-to-route extrapolation 11 2.8. Reliability 11 3. Results and discussion 13 3.1 MPRs 13 3.2 Odour thresholds 13 4. Re-evaluations 15 Abbreviations 22 Acknowledgement 22 References 23 Appendices 24 1 Metals 25 1.1 Arsenic 25 1.2 Barium 30 1.3 Cadmium 34 1.4 Chromium III 43 1.5 Chromium VI 47 1.6 Cobalt 58 1.7 Copper 62 1.8 Lead 66 1.9 Mercury 70 1.10 Molybdenum 75 1.11 Nickel 78 1.12 Zinc 82 2 Other inorganic compounds 86 2.1 Cyanides (free, complex, and thiocyanates) 86 3 Aromatic compounds 96 3.1 Benzene 96 3.2 Ethylbenzene 106 3.3 Toluene 111 3.4 Xylenes 117 3.5 Styrene 123 3.6 Phenol 128 3.7 Dihydroxybenzenes 132 3.8 Cresols 133 3.9 Phthalates 134 RIVM report 711701 025 page 5 of 297 4 Polycyclic aromatic hydrocarbons 143 4.1 Polycyclic aromatic hydrocarbons (PAHs) 143 5 Chlorinated hydrocarbons 153 5.1 1,2-Dichloroethane 153 5.2 1,2-Dichloroethene (cis and trans isomers) 157 5.3 Trichloroethene 162 5.4 Tetrachloroethene 171 5.5 Dichloromethane 178 5.6 Trichloromethane (chloroform) 183 5.7 Tetrachloromethane (carbon tetrachloride) 188 5.8 Chlorobenzenes (mono-, di-, tri- and hexachlorobenzenes) 193 5.9 Chlorophenols (mono-, di-, tri-, tetra- and pentachlorophenols) 217 5.10 Chloronaphtalenes (monochloronaphtalenes) 223 5.11 Vinylchloride 226 5.12 Dioxins, furans and dioxin-like PCBs 233 5.13 Polychlorinated biphenyls (non-planar PCBs) 237 6 Pesticides 244 6.1 Aldrin, dieldrin and endrin 244 6.2 DDT and its metabolites DDD and DDE 249 6.3 α-, β-, γ- and δ-Hexachlorocyclohexane (α-, β-, γ- and δ-HCH) 258 6.4 Carbamates: carbaryl and carbofuran 263 6.5 Dithiocarbamates: maneb 269 6.6 Triazines: atrazin 272 7 Other organic compounds 275 7.1 Pyridine 275 7.2 Tetrahydrofuran 276 7.3 Tetrahydrothiophene 277 7.4 Cyclohexanone 278 7.5 Petrol/gasoline 279 7.6 Total petroleum hydrocarbons (TPH; "minerale olie") 280 Mailing list 296 page 6 of 297 RIVM report 711701 025 Samenvatting Dit rapport geeft een overzicht van de opnieuw geëvalueerde humaan-toxicologische MTR waarden zoals in 1991-1993 afgeleid in het kader van het RIVM project betreffende interven- tiewaarden ten behoeve van bodemsanering. De voorliggende evaluaties werden uitgevoerd door het Centrum voor Stoffen en Risicobeoordeling van het RIVM. Tevens wordt een over- zicht gegeven van de wetenschappelijke uitgangspunten waarop de evaluaties zijn gebaseerd. Voor elke beoordeelde stof werden Maximum Toelaatbare Risico's afgeleid voor de orale blootstellingsroute, en indien relevant tevens voor de inhalatoire blootstellingsroute. Voor sommige stoffen kon geen MTR worden afgeleid wegens het ontbreken van toxicolo- gische gegevens, terwijl voor enkele stoffen slechts voorlopige (“provisional”) waarden kon- den worden afgeleid omdat het toxicologische informatiepakket voor de desbetreffende stof- fen incompleet was. RIVM report 711701 025 page 7 of 297 Summary This report contains an update of the human health-based MPR values for compounds and compound classes evaluated in the period 1991-1993, in the scope of the RIVM project on soil intervention values for soil clean-up. These updates have been performed by the Centre for Substances and Risk Assessment of the RIVM, in the years 1999 and 2000. Also the sci- entific basis for the evaluations is presented. For each substance evaluated, Maximum Permissible Risk levels are derived for the oral route of exposure and, if relevant, also for the inhalation route of exposure. In some instances the previously derived MPR values have been maintained due to lack of new and relevant data. For some substances only provisional values could be derived because of limitations in the available toxicological information. page 8 of 297 RIVM report 711701 025 1. Introduction The Intervention Values for soil and groundwater are one of the instruments of the Dutch Soil Protection Act: based on these values decisions are made regarding the clean-up of contaminated soils. In 1991 proposals have been derived for the first series of Intervention Values for about 70 (groups of) compounds. Since the promulgation of this first series of Intervention Values in 1994 more data, exposure models and calculation methods have become available. Also a large group of users of the Intervention Values (public and private environmental experts) have asked questions and elucidations on specific (groups of) compounds. In 1997 Intervention Values for the second and third series of compounds were established, followed by the fourth series of compounds in 2000. The Directorate General of Environment of the Ministry of Housing, Spacial Planning and the Environment commissioned RIVM to evaluate the existing Intervention Values, in order to have an up-to-date scientific basis for these values. This has led to the project ‘Evaluation of Intervention Values Soil’ which is carried out in the framework of the overall-project “Risk in relation to soil quality”. The main purpose of the evaluation is to obtain an adjusted systematic tool for deriving Intervention Values according to the most recent views on exposure assessment to soil contaminants. One of the building blocks for Intervention Values is the human-toxicological Maximum Permissible Risk (MPRhuman) value. The present study comprises the revision of the MPRs of the first series of compounds, which was reported by Vermeire et al. (1991) and Vermeire (1993). RIVM report 711701 025 page 9 of 297 2. General procedure 2.1. Definitions The MPRhuman is defined as the amount of a substance (usually a chemical substance) that any human individual can be exposed to daily during full lifetime without significant health risk (see paragraph 2.3 for the more specific definition of cancer risks). It covers both oral and in- halation exposure (and if necessary also dermal exposure), and classical toxic risks as well as carcinogenic risks. The MPRhuman is generally expressed as either a tolerable daily intake (TDI) or an excess carcinogenic risk via intake (CRoral), both covering exposure by oral in- gestion, or a tolerable concentration in air (TCA) or an excess carcinogenic risk via air (CRin- hal), both covering exposure by inhalation. The procedure to derive MPRshuman is outlined in detail by Janssen and Speijers (1997). In agreement with this report the approach of the present re-evaluation is a pragmatic one in that use has been made of existing toxicological evaluations by national and international bodies, in an attempt to avoid unwanted duplication of work. Existing evaluations were used in a critical fashion: on a case-by-case basis their adequacy for use in the present scope was judged, and from that the need to search additional and/or primary literature was determined. In the following the abbreviation "MPR" is used throughout to indicate the MPRhuman. 2.2. Threshold versus non-threshold approach In evaluating the toxicity of chemical substances, distinction must be made between two fun- damentally different approaches. Genotoxic carcinogens are assumed to exert their activity also at the smallest dose, i.e., by definition a threshold for genotoxic activity does not exist.