y, 38«, 5y, 535-545, 2005 Econ. Environ. Geol., 38(5), 535-545, 2005 m, w w sƒ *Á zk w y lœw Risk Assessment of Arsenic by Human Exposure of Contaminated Soil, Groundwater and Rice Grain Jin-Soo Lee* and Hyo-Taek Chon School of Civil, Urban and Geosystem Engineering, Seoul National University, Seoul 151-744, Korea Environmental survey from some abandoned metal mine areas was undertaken on to assess the risk of adverse health effects on human exposure to arsenic influenced by past Au-Ag mining activities. Elevated levels of As were found in tailings from the studied mine areas. This high concentration may have a impact on soils and waters around the tailing piles. In order to perform the human risk assessment, chemical analysis data of soils, rice grains and waters for As have been used. The HQ values for As via the rice grain and groundwater consumption were significantly higher compared with other exposure pathways in all metal mine areas. However, there were minimal soil and water dermal contact risks. The resulting HI values of As from the Dongil, Okdong and Hwacheon mine areas were higher than 5.0, and their toxic risk due to drinking water and rice grain was strong in these mine areas. The cancer risk of being exposed to As by the rice grain route from the Dongil, Okdong and Hwacheon mine areas was 5.2 10-4, 6.0 10-4 and 8.1 10-4, respectively. The As cancer risk via the exposure pathway of drinking water from these mine areas exceeded the acceptable risk of 1 in 10,000 for regulatory purposes. Thus, the daily intakes of groundwater and rice grain by the local residents from the Dongil, Okdong and Hwacheon mine areas can pose a potential health threat if exposed by long-term arsenic exposure. Key words : Arsenic (As), Exposure pathway, Toxic risk, Cancer risk, Human risk assessment s Ÿ ƒ e w w sƒw» w,,, š y Ÿ Ÿ, m, w w yw w. s Ÿ s» Ÿ ü w ùkû, w Ÿ ƒ ù w Ÿ w ù w y k ƒ j m,, w yw k w sƒ w. s Ÿ y mw m, w ( ),, y w m v, w w v 5ƒ q w. ƒ w sƒ, Ÿ w w mw w ƒ ƒ ùkû. p, Ÿ Ÿ HI ƒ 7.0, y Ÿ 5.0 ùkù w. w w sƒ, Ÿ, Ÿ y Ÿ mw w w y 5 8 ùkû. w w, w Ÿ 1 ùkû. EPA w w j w ( ) ù w» w ƒ e w w j š q.,, w, w, w sƒ *Corresponding author:g jsoolee@snu.ac.kr 535
536 Á zk 1. w xk w,,», m mw «,»«, m «, «sww yw y w» e vw š (Thornton, 1983; Alloway, 1990). x (As, Cd, Cu, Cr, Co, Hg, Pb, Se, Mo, Zn) w mw k w eš. p s Ÿ Ÿ ù ŸÁ Ÿ y w Ÿ s» (s, Ÿ, Ÿ s ) Ÿ e ù t w w Ÿ w jš (, 1997; y, 1998; y w, 2000). ù sƒ, p ƒ w w w ƒ w w sƒ l y w š. m, w y ü w e sƒw w sƒ» y w w š (Kolluru et al., 1996; Kimmel et al., 1999; Akagi et al., 2000; Alcock et al., 2000; Green et al., 2000; Lee et al., 2000; Paustenbach, 2002; Sekhar et al., 2003; Lee et al., 2004). p, 1980 Superfund» Superfund site w, mw Á w v. v ª e w l x š y yw, w sƒ y w w wš š w ³ w w sƒ ƒ w wù š. p, ù 1992 UNDP y z w w wyw w ƒ z w w wyw ƒ y š. ü y w sƒ w 1980 z l ù, w, w e w sƒw w sƒ w w w (, 2001;, 2003; zk, 2004; Lee et al., 2000; Lee et al., 2005a, 2005b; Chung et al., 2005), w k. 1992 l y G7» 2001 l y w mw w s ƒ ƒ w ù, y w w l y w» wš e w. w l e w(adverse effect) w dw» w s Ÿ Ÿ Ÿ, m, w ³ wš, yw k w q w e w( ) w w sƒ wwš w. 2. w sƒ w sƒ(human risk assessment) w ùkú vw y w w š w, y w (risk)» e w l w¾ m w, w, w, z w d š w, w» w w w. ƒ r š w sƒ ƒ z(nrc; National Research Council) w (NRC, 1983), w ³ w w y (hazard identification), w,,» w sƒ(exposure assessment), w w ³ w -
m, w w sƒ 537 Fig. 1. Risk assessment process (US EPA, 1989a). sƒ(dose-response assessment) w w sƒw w (risk characterization) 4 (Fig. 1). w y w sƒ(qualitative risk assessment) wš, - sƒ, sƒ, w w sƒ(quantitative risk assessment). 2.1. w y (Hazard Identification) w sƒ w y, ww w j ƒ w, w, yw q wš y» ü w» q w ƒ š w ³ w w (Kolluru et al., 1996; Paustenbach, 2002). w w x w w š š w w ƒƒ w y w x, yw w l. x e q,, m, w t k, ƒ (m, w, ) w, w sw, œ w w. 2.2. sƒ(exposure Assessment) sƒ j»,,», š mw w (Kolluru et al., 1996; Paustenbach, 2002). sƒ, y w ù w, z ü enw wƒ ƒ w ù w w ƒ f w x (CSM, conceptual site model) w, yw sƒ» w. š ù p q wš, w. ƒ p w w. p w ƒƒ s³ ADD (average daily dose, unit: mg/kg-day) w w (Kolluru et al., 1996; Paustenbach, 2002).
538 Á zk 2.3. - ( ) sƒ(dose-response Assessment) - sƒ w w w ³ wš w w w d w, x w m w (Kolluru et al., 1996; Paustenbach, 2002). q - (dose-response data) k sƒ, wƒ ü w e w, ü w e w (Kolluru et al., 1996; Paustenbach, 2002). w sƒ w ƒ x mw, x p ƒ w w ƒ x» š t y w. ƒ œ EPA œw IRIS (Integrated Risk Information System), ƒ e wš. ü w w - sƒ mw ƒ w IRIS l y w sƒ w. 2.4. w (Risk Characterization) w w sƒ 4, 3ƒ ww., ƒ mw ùkù y w d w w w w ùkü (Kolluru et al., 1996; Paustenbach, 2002). w y (, t, m ) mw w y ù ƒ w sƒ - sƒ mww p p, ù ù w w w y w. 2.4.1. w w ùkü e (SF; cancer slope factor) w - š û (low dose region)»» RfD ((mg/kg-day) -1 ). SF wš w» w q w w EPA w» wš (Table 1), A, B1, B2 w ³ w. w w w» w y 10 ( ) w, w (Kolluru et al., 1996; Paustenbach, 2002). w w, wƒ x w 10-6 ~10-4 wš. Cancer risk = ADD (average daily dose) SF (slope factor) 2.4.2. w w ( ) RfD (reference dose) w w e w. x mw Table 1. Classification of chemicals according to the weight of evidence from animal experiments, clinical experience and epidemiologic studies. Category Criteria A Human carcinogen (sufficient evidence of carcinogenicity in humans) B1 Probable human carcinogen (limited evidence of carcinogenicity in humans) B2 Probable human carcinogen (sufficient evidence of carcinogenicity in animals with inadequate or lack of evidence in humans) C Possible human carcinogen (limited evidence of carcinogenicity in animals with inadequate or lack of human data) D Not classifiable as to human carcinogenicity (inadequate or no evidence) E Evidence of noncarcinogenicity for humans (no evidence of carcinogenicity in adequate studies)
m, w w sƒ 539 k w e,»,, ü, û, ƒ wš (Kolluru et al., 1996; Paustenbach, 2002). ƒ w y w» w UF (uncertainty factor) w, w» w 10, ü w» w 10,»» w» w 10 w. ƒƒ ƒ UF. w ƒ ù x w» w ƒ MF (modifying factor) w 1 10. - x w (NOAEL, no observed adverse effect level) UF MF ù š (RfD) (Kolluru et al., 1996; Paustenbach, 2002). š w w ù d w. w - sƒ mw RfD mw sƒw, w x HQ (Hazard Quotient) ùkü, w ù w HQ ww x HI (Hazard Index) ùkü. w (Kolluru et al., 1996; Paustenbach, 2002). eƒ 1.0 w w w( ) w ƒ w, 1.0 w w ƒ ùkü. HQ = ADD (from exposure assessment) HQ = / RfD (from IRIS of US EPA) HI = HQs (sum of hazard quotients) HI = {ADD 1 /RfD 1 + ADD 2 /RfD 2 + HI = + ADDi/RfDi} 3. sÿ w sƒ 3.1. s Ÿ w w s ƒ ww» w 5 sÿ (,,, š y Ÿ ) w. Ÿ w š mx w Au, Ag, Cu, Zn Ÿ. Ÿ d n z w x Ÿ Ÿ Ÿ y,,, y,, ( x, 1993), 1975 l ƒw {Ÿ k ù»k ù w y. Ÿ w» w t, sˆ ˆ w s sÿ ˆ e š w y 2 e Ÿ w sw. Ÿ w w Cu, Pb, Zn Ÿ. Ÿ» n w w,, Ÿ Ÿ y,,, y, œ ( wÿ œ, 1981). Ÿ» 1936 l 1979 ¾ Ÿ w» Ÿ 1,850 m š ( wÿ œ, 1978). ù 1988 z sÿ k, Ÿ w ƒ ù Ÿ w e š ew š w k. Ÿ w t 2 w, Au, Ag, Cu w Ÿ. Ÿ d ü y d w Ÿ. 1933 l ƒw 1976 {Ÿ k ù w y. x y s t, s w š w mw xw. šÿ w 185-6 w, Au, Ag, Cu w Ÿ. Ÿ d ü w Ÿ, Ÿ 80 ƒ œ w ˆ ƒ w, š, Ÿ s e š š» mw w» w. y Ÿ w y 1 56 w, Au, Ag, Pb, Zn
540 Á zk w Ÿ. Ÿ y w Ÿ, Ÿ Ÿ ƒ w y û Ÿ ƒ Ÿ w w e. š Ÿ m w wš ù. 3.2. x s Ÿ Ÿ m w w w w Table 2 ù kü. w m ü w š w w yw Table 2 w. ü w w sƒ w. w sƒ s Ÿ Ÿ s» Ÿ w w wš, Ÿ w Ÿ w ew jš, w. w Ÿ Ÿ e w w Ÿ ƒ Ÿ w ( t w ) k. Table 2. Arsenic concentration in tailings, soils, groundwaters and rice grains from the abandoned metal mine areas (unit in mg/kg). Mine Tailings Agricultural soils Groundwaters* Rice grains Dongil N 4 7 3 2 mean value 8720 36 0.039 0.15 Okdong N 4 9 7 2 mean value 72 14 0.038 0.17 Dongjung N 2 7 2 - mean value 3620 95 0.009 - Dogok N 9 6 2 - mean value 220 8 0.001 - Hwacheon N 2 13 2 3 mean value 72 20 0.007 0.23 N = number of samples, * Groundwater is used for drinking water. Fig. 2. Conceptual site model (CSM) for risk assessment in the abandoned metal mine areas.
m, w w sƒ 541 s Ÿ w, w m, w w. s Ÿ - y w w x (CSM) Fig. 2. m ù w, y w m ù w w v 5ƒ q. 3.3. s Ÿ CSM m ù w Table 3. Equations of average daily dose (ADD) with different exposure pathways (unit in mg/kg-day). Exposure pathway Average daily dose or intake Soil ingestion Water ingestion Rice grain ingestion Dermal contact of soil Dermal contact by showering ADD =-------------------------------------- C IRs ED EF BW AT 365 ADD =---------------------------------------- C IRw ED EF BW AT 365 ADD =-------------------------------------- C IRr ED EF BW AT 365 ADD =------------------------------------------------------------------- C SAs AF ABS ED EF BW AT 365 ADD =---------------------------------------------------------------- C SAw PC ET ED EF BW AT 365 Table 4. Exposure factors and parameters for risk assessment. v q s³ w w Table 3. w» w ƒ q w. EPA w w ƒ, p, 1989 z 1997 w (Exposure Factors Handbook) ww w ƒwš mw w «š wš (US EPA, 1989b, 1997). w w w p w ƒ ƒ w default. ù, ù w w» ƒ w s³ EPA w, ü m w (Table 4). ƒƒ w. m : EPA (1997) w s³ m (soil ingestion rate) 50 mg/ day «šwš. : 1980 EPA 2L/ day t e x ¾ ƒ š e. : ù Factor/Parameter Symbol Units Residential Data sources Exposure Duration ED years 30 US EPA, 1997 Exposure Frequency EF days/year 350 US EPA, 1997 Averaging Time AT Carcinogens ATc years 76.5 KNSO, 2001 Non-carcinogens ATnc years 30 US EPA, 1997 Body Weight BW kg 60 MOCIE, 1997 Ingestion rate IR Soil IRs kg/day 50 10-6 US EPA, 1997 Rice (Farmer) IRr kg/day 0.374 KNSO, 2002 Drinking water IRw L/day 2.0 US EPA, 1997 Skin surface area SA Skin surface area (forearms, hands) SAs cm 2 1960 US EPA, 1997 Skin surface area (whole body) SAw cm 2 16000 US EPA, 1997 Adherence factor AF mg/cm 2 0.5 US EPA, 1997 Absorption factor ABS - 0.01 US EPA, 1997 Skin permeability constant PC cm/hr 3 10-4 US EPA, 1996 Exposure time for showering ET hr/day 0.333 US EPA, 1997
542 Á zk m yw w, mw v w. 2002 ù m š w ƒ w 1 w s³ (rice grain ingestion rate) 238.4 g š, ƒ 374.2 g š, ƒ 226.3 g. : t,» wì sƒ v w wù. s³ (ADD)» s³ w w. x EPA «še û 78.1 kg, 65.4 kg, s³ 71.8 kg (US EPA, 1997). ù s³» t w t š (1997) w, (19 ) û s³ 65.7 kg, s³ 54.2 kg, s³ 60.0 kg ü w sƒ s³ 60 kg w w.» (s³ ) : w sƒ š w w š w., ƒ» w f» ¼ w. x EPA 70 ƒ w wš ù, ù m 2001 w, û 72.8, 80.0, s³ 76.5 šw š. t : v w t (SA, skin surface area) w w, ù p w t v w. EPA v t 16000cm 2, m w v t 1960cm wš 2.,», v n,, w EPA l w (US EPA, 1996, 1997), 365 yr day ã y. 3.4. - sƒ w sƒ mw w w w w w» w - sƒ mw (SF) š (RfD) eƒ v w. yw EPA w, A w w, IRIS l w SF 1.5(mg/ kg-day) wš -1. w w s w w š RfD 3 10-4 mg/ kg-day wš. 3.4.1. w s Ÿ w ƒ x HQ ww w HI Table 5 w. Table 5 w 5ƒ HQ e w, Ÿ w w ƒ Ÿ mw w ƒ ƒ ùkû., m ù m w v mw HQ ƒ Ÿ 1.0 w ù kù mw w ƒ w q. ù 5ƒ ww HI ƒ šÿ w Ÿ 1.0 w ƒ w ùkû, p Ÿ Ÿ HI ƒ 7.0, y Ÿ 5.0 Table 5. Hazard index (HI) and hazard quotient (HQ) of As according to exposure routes in the abandoned metal mine areas. Exposure Hazard Quotient (HQ) route Soil Water Rice grain Soil dermal Water dermal HI Mine ingestion ingestion ingestion contact contact Dongil 0.066 4.155 2.989 0.005 0.003 7.2 Okdong 0.026 4.049 3.387 0.002 0.003 7.5 Dongjung 0.174 0.959 NR 0.013 0.001 1.1 Dogok 0.015 0.107 NR 0.001 0.000 0.1 Hwacheon 0.037 0.746 4.582 0.003 0.001 5.4 NR : No risk for rice grain ingestion due to no cultivation of rice crops around the Dongjung and Dogok mine areas.
m, w w sƒ 543 Table 6. Cancer risk of As according to exposure routes in the abandoned metal mine areas. Mine ùkù w w ù ( ), m w w w ƒ w ƒ j wš. 3.4.2. w s Ÿ ƒ w sƒ Table 6 ùkü. w Ÿ, Ÿ y Ÿ mw w w y 5 8 (5 10-4 ~8 10-4 ) ùkû. w w, w Ÿ Ÿ 7 (7 10 ) -4 ùkû. ù m w w Ÿ 10-5 w, m w v w 10 w -6 û ùkû. EPA w w w w 10-6 ~10 wš -4 (US EPA, 1996), FDA (Food and Drug Administration) w 10-4 w w wš. Ÿ, Ÿ y Ÿ w ( ) mw w ƒ w zwš ù w» w ƒ e w( ) j š q. 4. Exposure route Soil ingestion Water ingestion 5 s Ÿ Ÿ, m, w ( ) w y w sƒw. (1) s Ÿ Ÿ ü w Ÿ Rice grain ingestion Soil dermal contact Water dermal contact Dongil 1.2 10-5 7.3 10-4 5.2 10-4 2.3 10-6 5.9 10-7 Okdong 4.5 10-6 7.1 10-4 6.0 10-4 8.8 10-7 5.7 10-7 Dongjung 3.1 10-5 1.7 10-4 NR 6.0 10-6 1.4 10-7 Dogok 2.6 10-6 1.9 10-5 NR 5.1 10-7 1.5 10-8 Hwacheon 6.5 10-6 1.3 10-4 8.1 10-4 1.3 10-6 1.1 10-7 NR : No risk for rice grain ingestion due to no cultivation of rice crops around the Dongjung and Dogok mine areas. Ÿ ƒƒ 8720 mg/kg 3620 mg/ kg ùkû. šÿ Ÿ ü w 220 mg/kg, Ÿ y Ÿ 72 mg/kg ùkû. w wš Ÿ Ÿ ù w w m jš. (2) m ü w m x w e(20 As mg/kg) w, Ÿ, Ÿ y Ÿ w e wš. 5 s Ÿ Ÿ, Ÿ y Ÿ 3œ Ÿ ƒ š q, ü w ù s³ ü w 0.09 mg/kg ùkû. Ÿ š w ü w ù» e 50 ppb w ù, Ÿ Ÿ w ü w WHO» e 10 ppb w ùkû. (3) s Ÿ - y w w x (CSM) w, y mw m, w ( ),, y w m v, w w v 5ƒ q w. (4) ƒ w sƒ, Ÿ w w mw w HQ ƒ w ùkù mw w ƒ j wš. w, w s Ÿ w w š q w. wr, Ÿ Ÿ HI ƒ 7.0, y Ÿ 5.0 ùkû ù, šÿ 0.1 û
544 Á zk ùkù w w ƒ w. (5) w w sƒ, Ÿ, Ÿ y Ÿ» e mw w w y 5 8 (5 10-4 ~8 10-4 ) ùkû. w w, w Ÿ Ÿ 7 (7 10-4 ) ùkû. EPA w w j w ( ) ù w» w ƒ e w w j š q. (6) 5 s Ÿ w w s ƒ, Ÿ w Ÿ > Ÿ >y Ÿ > Ÿ > šÿ ùkû. w sÿ Ÿw w ù w w te w y w. y m y ( y: 20050000000000-S0-0-004-0-0-2005) w, w w œw.. š x wÿ œ (1978) Ÿ š. wÿ œ (1981) w Ÿ. 8y, r.,, x, û (1997) Ÿ Ÿw. š KR-97 (C)-32, w, 479p., Ben A Klinck, zk (2001) w sƒ. w œwz, 38 «2y, p.136-145., zk (2004) Ÿ w sƒ. y, 37«1y, p.73-86., zk, ½, ½ (2003) s Ÿ w w sƒ. w l œwz, 40«4y, p.264-273. x, ½, x,, ½ (1993) û m Ÿy. Ÿ, 26«, p. 311-325. y (1998) s Ÿ k š. y w,, s, z (2000) - Ÿ m. w m y w z, 5«, p.67-85. Akagi, H., Castillo, E.S., Cortes-Maramba, N., Francisco- Rivera, A.T. and Timbang, T.D. (2000) Health assessment for mercury exposure among schoolchildren residing near a gold processing and refining plant in Apokon, Tagum, Davao del Norte, Philippines. The Science of the Total Environment, v.259, p.31-43. Alcock, R.E., Sweetman, A.J., Juan, C.Y. and Jones, K.C. (2000) A genetic model of human lifetime exposure to persistent organic contaminants: development and application to PCB-101. Environmental Pollution, v.110, p.253-265. Alloway, B.J. (1990) Heavy metals in soils, Blackie and Son Ltd. Chung, E.H. Lee, J.S. Chon, H.T. and Sager, M. (2005) Environmental Contamination and Digestibility of Arsenic and Heavy Metals around the Dongjeong Au- Ag-Cu mine, Korea. Geochemistry: Exploration Environment Analysis, v.5, p.69-74. Green, E., Short, S.D., Stutt, E. and Harrison, P.T.C. (2000) Protecting environmental quality and human health: strategies for harmonization. The Science of the Total Environment, v.256, p.205-213. Kimmel, G., Ohanian, E. and Vu, V. (1999) Framework for human health risk assessment. Human and Ecological Assessment, v.5, p.997-1001. KNSO (2001, 2002) Korea National Statistical Office. http://www.nso.go.kr. Kolluru, R.V., Bartell, S.M., Pitblado, R.M. and Stricoff, R.S. (1996) Risk Assessment and Management Handbook. McGrow-Hill, New York, 870p. Lee, S.C., Guo, H., Lam, S.M.J. and Lau, S.L.A. (2004) Multipathway risk assessment on disinfection by-productions of drinking water in Hong Kong. Environmetal Research, v.94, p.47-56. Lee, J.S., Chon, H.T. and Jung, M.C. (2005a) Toxic risk assessment and environmental contamination of heavy metals around abandoned metal mine sites in Korea. Key Engineering Materials, v.277-279, p.542-547. Lee, J.S., Chon, H.T. and Kim, K.W. (2005b) Human risk assessment of As, Cd, Cu and Zn in the abandoned metal mine site. Environmental Geochemistry and Health, v.27, p.185-191. Lee, J.S., Klinck, B. and Moore, Y. (2000) Dispersal, risk assessment modelling and bioavailability of arsenic and other toxic heavy metals in the vicinity of two abandoned mine sites in Korea. British Geological Technical Report WE/00/1, 91p. MOCIE (1997) Ministry of Commerce, Industry and Energy. http://www.mocie.go.kr. NRC(National Research Council) (1983) Risk assessment in the Federal Government: Managing the process. National Academy Press, Washington. Paustenbach, D.J. (2002) Human and Ecological Risk Assessment: Theory and Practice. John Wiley and Sons, New York. Sekhar, K.C., Chary, N.S., Kamala, C.T., Rao, J.V., Balaram, V. and Anjaneyulu, Y. (2003) Risk assessment and pathway study of arsenic in industrially contaminated sites of Hyderabad: a case study. Environment International, v.29, p.601-611. Thornton, I. (1983) Applied environmental geochemistry. Academic Press, London, 501p.
m, w w sƒ 545 US EPA (1989a) Risk assessment guidance for superfund: Volume I Human health evaluation manual (Part A). EPA/540/1-89/002, Environmental Protection Agency, Office of Emergency and Remedial Response, Washington, D.C., USA. US EPA (1989b) Exposure Factors Handbook. EPA/600/ 8-89/043, Environmental Protection Agency, Office of Research and Development, OH, USA. US EPA (1996) CalTOX: A multimedia total exposure model for hazardous waste site. Technical Report. US EPA (1997) Exposure factors handbook. EPA/600/P- 95/002Fa (Update to Exposure Factors Handbook, EPA/600/8-89/043), Environmental Protection Agency Region I, Washington, D.C., USA. 2005 8 9 š, 2005 9 8.