Geological Society of Malaysia Annual Geological Conference 2001 June 2-3 2001, Pangkor Island, Perak Darul Ridzuan, Malaysia

Minor and trace metals in slurry slime in mined-out ponds in the Kinta Valley, Perak

CHOW WENG SUM

Minerals and Geoscience Department Malaysia 201h Floor, Tabung Haji Building, Jalan Tun Razak, P.O.Box 11110, 50736 Kuala Lumpur

Abstract: The Kinta Valley was renowned as the largest tin field in the world and up to 1989, there were 70,158 hectares of land under mining leases. Thereafter, the tin mining industry took a down-tum due to falling tin metal prices and what is left of the industry is now mined-out land with abundant abandoned ponds. Stretching from Pengkalan near lpoh to Kampar in the south over a distance of 42km, there is a total of 1,194 mined-out ponds. About 66.7% of these ponds have slurry slime at the pond bottoms, with thickness varying from O.lm to 7.0m. Many of these abandoned ponds are used for the rearing of fish and ducks, or are cultivated with lotus plants. Slime is occasionally admixed with tailing sand for agricultural purposes. As such, should the slime be contaminated with heavy metals the food chain will be affected. Slime from eight ponds in the Kinta Valley was tested for minor and trace metals. Most of the slime contained higher concentrations of uranium and other trace heavy metals such asSn, Hg, Sb, 8i and Cd as compared to the norm in the earth's crust or stream sediments. Amongst the eight test ponds, slime from Pond 881 contained relatively higher concentrations of minor, radioactive and trace metals. Slime from Pond 881 should not be utilised as fill material as the concentration of as is above the trigger concentration and threshold value. It should also not to be used for the planting of crops as the level of zinc is high.

INTRODUCTION to the environment and to study whether concentrations of precious, radioactive, minor or trace heavy metals present The Kinta Valley was renowned as the largest tin field in the slurry slime conform to the norm in earth's crust or in the world and up to 1989, there were 70,158 hectares of are similar to that in the stream sediments. land under mining leases. Thereafter, the tin mining industry took a down-tum due to falling tin metal prices and what METHOD OF STUDY is left of the industry is now mined-out land with abundant abandoned ponds. Stretching from Pengkalan near lpoh to To study the distribution of heavy metals in the slurry Kampar in the south over a distance of 42km, there is a slime, eight ponds, five of which (Ponds E814, B72, B20, total of 1,194 mined-out ponds (Figure 1). About 66.7% of B 141 and B81) are left overs of the palong method of these ponds have slurry slime at the pond bottoms, with mining and the remaining three (Ponds B 122, B 127 and thickness varying from 0.1m to 7 .Om. Some of these ponds BS) which are abandoned dredged ponds were selected have been utilised for the rearing of fish or ducks. Some of (Table 1). the more shallow ponds are cultivated with lotus plants and Slurry slime was collected with a slime bailor and air­ the seeds and roots of the plants are considered a culinary dried and then crushed in an agate mortar. The crushed delicacy. Slime from some of the ponds has also been recovered samples were sieved to minus 80 mesh. A portion of the and admixed with tailing sand for agricultural purposes. sieved samples was analysed by Atomic Absorption As slurry slime from these mined-out ponds is Spectrophotometer for bismuth (Bi), cadmium (Cd), derived from the beneficiation of mineralised residual soil chromium (Cr), lead (Pb), copper (Cu), zinc (Zn), cobalt or alluvium, it may contain unusually higher concentrations (Co), nickel (Ni), iron (Fe), manganese (Mn), silver (Ag), of heavy metals such as Fe, Cu, Zn or As, which are molybdenum (Mo) and antimony (Sb). For mercury (Hg), associated with gangue minerals such as arsenopyrite, pyrite, a cold-vapour atomic absorption method was employed chalcopyrite or sphalerite. Should fishes ingest such slurry using a Coleman MAS-50 analyser. For the analysis of slime or crops cultivated on such slime, the plants and uranium (U), a fluorometer was used. fishes may absorb the heavy metals and may contaminate To analyse for tin (Sn), tungsten (W )and arsenic (As), the food chain. the samples were further crushed to minus 150 to minus 200 mesh and the colorimetry method modified from OBJECTIVES OF INVESTIGATION Stanton (1966) was employed. The methods of analyses for all 18 elements were The objectives of this investigation are to determine if adopted after the Geological Survey Special Paper 3 (GSD, the concentrations of metals in the slurry slime are hazardous 1981). 302 CHow WENG SuM

Table 1. List of ponds tested for heavy metals in study area. Pond No. Mukim Longitude Latitude Mining Method Bedrock Geology E814 Kampar 101 ° 7'37.21" 4° 19' 13.46" Palong Limestone B72 Tg. Tualang 101 ° 4' 14.43" 4° 20' 11.39" Pa1ong Limestone with schist lenses B20 Tg. Tualang 101 ° 3' 18 .23" 4° 24' 50.12" Pa1ong Limestone B141 Teja 101 ° 5' 26.58" 4° 22' 3.04" Palong Deep limestone B81 Tg. Tua1ang 101 ° 2' 30.38" 4° 20' 48.60" Palong Schist with limestone lenses Bl22 Tg. Tualang 101 ° 4' 51.64" 4° 21' 46.35" Dredging Limestone with schist lenses B127 Teja 101 ° 5' 0" 4° 20' 51.03" Dredging Limestone B5 Tg. Tualang 101 ° 3' 25.06" 4° 24' 28.86" Dredging Deep limestone

composition and the concentration of elements in the rocks may not conform to that as shown in Figure 2. Geochemical analyses of stream sediments collected . . ' from the Kuala Pilah - Gemas area (Abdul et al., 1995 ), .' r Boundary Range area which is around the Kelantan - < 1\EOAH i ·' Trengganu - Pahang border (Chu et al., 1986), South / -·, Kelantan (Chu et al., 1982) and within the Kenyir Reservou in Trengganu (Chow, 1986) (Table 2) showed that mercury ./'·· ...... _ .i !" ~ - is present in the order of 10'2 ppm, silver, 10'2 to 10'1 ppm ( and uranium 10·1 to 10° ppm. Seven other metals, namely, I K ELANTAN I molybdenum, tungsten, antimony, bismuth, nickel, coba~ t and arsenic have concentrations in the order of 10° ppm. Tin and copper vary between concentrations of 10° to 1" 1 ppm. Lead, zinc and manganese are present in higher concentrations, with lead and zinc in the order of 10 1 pp and manganese, 102 ppm. Iron has the highest concentratio .:~ in the stream sediments and are present in the order of 100%.

',) PAHANG RESULTS ...... ,

-~ ~ ..... The concentrations of precious (silver), radioactive ( (uranium), minor (iron and manganese) or trace (molybdenum, copper, zinc, chromium, tin, tungsten, mercury, antimony, bismuth, cadmium, lead, nickel, cobalt and arsenic) metals in the slurry slime from the eight test ponds were analysed and compared with the average concentration in the earth's crust (as depicted in Figure 2 Figure 1. Location of the study area. which is after Darnley et al., 1995) and the concentrations in stream sediments (Table 2) in the Kuala Pilah-Gema" NATURAL BACKGROUND VALUES area (Abdul et al., 1995), Boundary Range area (Chu et al. , 1986), South Kelantan area (Chu et al., 1982) and th The average abundance of the 18 elements within the Kenyir Reservoir area (Chow, 1986). earth's crust are shown in Figure 2. Silver and mercury are Precious Metal found in the order of 1o- 2 ppm in the earth's crust. Of slightly higher concentrations are cadmium, antimony and One precious metal silver (Ag) was analysed. Silve1· bismuth, which are found in the order of 10·1ppm. Uranium, (A g) is normally present in low concentrations in the earth' s arsenic, tungsten, tin and molybdenum are present in crust and in the stream sediments (in the order of 10- z concentrations in the order of 10° ppm. Following these are ppm). cobalt, nickel, copper, lead and zinc which are present in Silver(Ag) the order of 101 ppm in the earth's crust. Of even higher concentrations are chromium, manganese and iron, which All slurry slime samples, except for two, B 1_41/S 1 and are present in the order of 102 ppm, 103 ppm and 104 ppm B 127 /S2, had concentrations of silver (Ag) (Table 3) highe.,.. respectively. than the average in the earth's crust which is in the orde However, it must be borne in mind that the granitic of 10·2 ppm (Figure 2) as well as that of stream sedi ment ~· rocks which are found in the Kinta Valley are acidic in from the Kuala Pilah - Gemas area, Boundary Range area, Geological Society of Malaysia Annual Geological Conference 2001 MINOR AND TRACE METALS IN SLURRY SLIME IN MINED-OUT PONDS IN THE KINTA V ALLEY, PERAK 303

Table 2. Concentrations of precious, radioactive, minor and trace metals in stream sediments. Note:Geochemical results of the Kuala Pilah - Gemas area are after Abdul eta/., 1995; the Boundary Range area after Chu et al., 1986; the South Kelantan area after Chu et al. , I 982; and the Kenyir Reservoir area after Chow, 1996.

Total no. Locality Mo Cu Zn Cr Sn w Hg Sb Bi Cd Pb Ni Co As Fe Mn Ag u of samples ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm % ppm ppm ppm 512 Kuala Pilah - 1.0 30.0 29.0 - 10.0 3.0 0.07 2.0 1.0 14.0 4.0 4.0 8.0 1.9 155 0.08 1.17 Gemas area 3844 Boundary Range area (Kelantan-Terengganu u 9.4 43.0 5.2 2.5 0.06 19.0 3.7 3.7 /6.0 2.0 250 0.02 0.19 -Pahang border) 4360 South Kelantan 1.4 12.0 40.0 9.0 1.4 0.06 16.0 5.0 5.0 4.0 2.1 240 0.16 0.3 1000 Kenyir Reservoir 1.5 6.4 37.0 6.0 2.6 - 19.0 2.8 4.4 6.6 2.0 120 0.05 1.20

South Kelantan area and Kenyir Reservoir area which varied crust (Figure 2), but is very close to the stream sediments from 0.02 to 0.16 ppm (Table 2). from the Kuala Pilah - Gemas, Boundary Range, South Pond B81 in particular contained high concentrations Kelantan and the Kenyir Reservoir areas which varied of si lver, with values recording 0.7 ppm between a depth of between 120 to 250 ppm (Table 2). However, at certain 4.5 to 5.5m and 1.00 ppm at a depth of 6.5. to 7.5 mm. depths in Ponds B 18, E814 and B20, the concentration of manganese was slightly higher. At a depth of 3.5 to 8.5m Radioactive Metal in Pond B8 1, the concentration of manganese was between Uranium, which is radioactive was analysed. In the earth's 501 to 792 ppm. Pond B20 had between 576 to 605 ppm at crust, uranium is present in the order of 10° ppm (Figure 2) a depth of 5.6 to 9.6m. The entire profile of slurry slime in and in stream sedim~nts, 10· 1 to 10° ppm (Table 2). Pond E8 I 4 had high concentrations of manganese varying between 577 to 629 ppm. Uranium (U) Most of the slurry slime samples have concentrations Trace Metals of uranium which are comparatively higher (Table 3) than Fourteen trace metals with concentrations less than that in the earth's crust (Figure 2) or in the stream sediments 100 ppm were analysed. The elements were molybdenum, from the Kuala Pilah - Gemas, Boundary Range, South copper, zi nc, chromium, tin, tungsten, mercury, antimony, Kelantan and the Kenyir Reservoir areas where the uranium bismuth, cadmium, lead, nickel, cobalt and arsenic. varied between 0.19 to 1.20 ppm (Table 2). Slurry slime in Pond B81, in particular, contained elevated concentrations Molybdenum (Mo) of uranium, reaching up to 21 ppm between a depth of 3.5 Slurry slime samples from all ponds, except that from to 5.5m. Pond B 122, had molybdenum varying between 1. 8 to 5.2 ppm (Table 5). These values are close to the average Minor Metals concentration in the earth's crust (Figure 2), as well as that Two minor metals, iron and manganese were analysed. in the stream sediments from the Kuala Pilah - Gemas, These two metals are normally present in the order of I 04 Boundary Range, South Kelantan and Kenyir Reservoir ppm and 103 ppm respectively in the earth's crust (Figure areas where concentrations of 1.0 to 1.5 ppm were recorded 2). In the stream sediments, iron is present in the order of (Table 2). The concentration of molybdenum in slurry 104 ppm or (10° %) and Mn 102 ppm (Table 2). slime in Pond Bl22 was relatively higher, varying between 12 to 19 ppm. Iron (Fe) Except for Pond B81 which had between 2.0 to 2.6% Copper(Cu) of Fe at a depth of 3.5 to 8.5m, all other samples in the The concentration of copper in slurry slime in five of remaining 7 ponds generally had between 0.4 to 1.3% of the ponds (B 122, B 127, E814, B72 and B20) varied between iron (Table 4). These concentrations are close to the average 11 to 30 ppm. Slurry slime in Pond B81 contained relatively in the earth's crust (Figure 2) as well as that of stream higher concentrations of Cu, varying between 36 to 81 ppm sediments in the Kuala Pilah - Gemas, Boundary Range, (Table 5). These concentrations are generally within the South Kelantan and Kenyir Reservoir areas which varied average concentration in the earth's crust, which is in the between 1.9 to 2.1 % (Table 2). order of l 0 1 ppm (Figure 2) as well as that in the stream sediments in the Kuala Pilah - Gemas, Boundary Range, Manganese (Mn) South Kelantan and Kenyir Reservoir areas which varied The concentration of Mn in the slurry slime in most between 6.4 to 30.0 ppm (Table 2). Slurry slime from the ponds generally varied between 115 to 430 ppm (Table 4) remaining two ponds B5 and B141 however, contained which is below the average concentration in the earth's lower concentrations of Cu, varying between 4 to 10 ppm.

June 2-3 2001, Pangk.or Island, Malaysia 304 CHow WENG SuM

Table 3. Concentration of precious and raclioactive metals in slurry Table 4. Concentration of minor metals in slurry slime. slime. Pond Sample Sam_j)le Der th (m) Minor Metals Pond Sample Sample Depth (m) Precious Radioactive No. No. From To Mid-point Fe(%) Mn (ppr1) No. No. Metal Metal S1 0.9 1.9 1.4 0.4 116 From To ~id - point Ag (ppm) U (ppm) 8141 S2 1.9 2.9 2.4 0.4 130 S1 0.9 1.9 1.4 0.05 2.1 S3 2.9 3.9 3.4 0.9 220 8141 S2 1.9 2.9 2.4 0.10 3.4 S4 3.9 4.9 4.4 1.2 316 S3 2.9 3.9 3.4 0.20 4.5 l.!:l ~ - ~ i.U 11 !:l S4 3.9 4.9 4.4 0.30 5.8 ~~ 2.5 3.5 ~ : ~ 1.3 204 Cil 1.!:> ~.!:> ~.u U . ~U f.J S3 3.5 4.5 4.0 2.4 659 S2 2.5 3.5 3.0 0.40 10.6 881 S4 4.5 5.5 5.0 2.6 792 S3 3.5 4.5 4.0 0.40 21.3 S5 5.5 6.5 6.0 2.0 501 881 S4 4.5 5.5 5.0 0.70 21.0 S6 6.5 7.5 7.0 2.6 771 S5 5.5 6.5 6.0 0.50 15.9 S7 7.5 8.5 8.0 2.3 524 S6 6.5 7.5 7.0 1.00 18.8 <: .1 J.1 1.J 4U S7 7.5 8.5 8.0 0.60 13.8 ~~ 3.1 4.1 ~:~ 1.2 350 8122 S3 4.1 5.1 :::>1 ~.1 ::!.1 ~.b U.1U 1~.!:> 4.6 1.1 358 S2 3.1 4.1 3.6 0.20 12.7 S4 5.1 6.1 5.6 1.2 362 8122 S3 4.1 5.1 4.6 0.20 11.5 S5 6.1 7.1 6.6 1.2 358 S4 5.1 6.1 5.6 0.30 13.5 S6 7.1 8.1 7.6 1.1 334 S5 6.1 7.1 6.6 0.40 14.4 u.r ::!1U S6 7.1 8.1 7.6 0.30 17.0 ~~ ~ : ~ ~ : ~ ~ : ~ 0.8 350 :::>1 l.tl ~.ts ~.::! u.~u !:l.tl S3 3.8 4.8 4.3 0.7 300 S2 2.8 3.8 3.3 0.05 9.8 8127 S4 4.8 5.8 5.3 0.7 313 S3 3.8 4.8 4.3 0.30 10.7 S5 5.8 6.8 6.3 0.8 322 8127 S4 4.8 5.8 5.3 0.10 14.9 S6 6.8 7.8 7.3 0.6 290 S5 5.8 6.8 6.3 0.20 11.0 S7 7.8 8.8 8.3 0.7 319 S6 6.8 7.8 7.3 0.30 9.7 S8 8.8 9.8 9.3 0.7 317 S7 7.8 8.8 8.3 0.20 8.0 ::>1 ~.1 J.1 ~-~ 1 . ~ ~4tl S8 8.8 9.8 9.3 0.20 11.6 S2 3.1 4. 1 3.5 1.1 212 85 S3 4.1 5.1 :::> 1 ~.1 ::!.1 ~.!:> U.::!U 4.5 1.0 178 S2 3.1 4.1 3.5 0.40 ~~:~ S4 5.1 6.1 5.5 0.9 165 B5 S3 4. 1 5.1 4.5 0.30 10.9 S5 6.1 7.1 6.5 0.8 151 S4 5.1 6.1 5.5 0.30 11.2 S6 7.1 8.1 7.5 0.9 157 S5 6.1 7.1 6.5 0.10 9.5 S7 8.1 9.1 8.5 0.9 160 S6 7.1 8.1 7.5 0.20 10.9 g 1 .~ !)(( S7 8.1 9.1 8.5 0.10 9.8 E81 4 ~~ ~ : ~ ~:~ 0.8 629 S3 3.8 4.8 4.3 1.ts ~.ts ~.::! U.!:JU tl.!:l 0.8 588 E814 ~~ 2.8 3.8 3.3 0.30 5.9 S4 4.8 5.8 5.3 0.8 592 S3 3.8 4.8 4.3 0.30 6.3 1.U Jots S4 4.8 5.8 5.3 0.40 5.8 ~~ ~:~ ~:~ ~: ~ 1.0 302 :::>1 Ui 1.1 U.1U i<:.U S3 2.6 3.6 3.1 0.9 260 S2 ~:~ 2.6 2.1 0.30 12.3 872 S4 3.6 4.6 4.1 0.9 332 S3 2.6 3.6 3.1 0.40 12.6 S5 4.6 5.6 5.1 0.9 249 872 S4 3.6 4.6 4.1 0.40 13.3 S6 5.6 6.6 6.1 0.7 255 S5 4.6 5.6 5.1 0.20 13.1 S7 6.6 7.6 7.1 0.8 269 S6 5.6 6.6 6.1 0.20 12.3 U.tl JUU S7 6.6 7.6 7.1 0.30 12.4 ~~ ~:~ ~:~ ~:~ 0.8 320 U.ti 1.0 1.1 U.1U 11.1 S3 2.6 3.6 3.1 0.8 310 ~~ 1.6 2.6 2.1 0.10 11 .9 S4 3.6 4.6 4.1 0.8 381 S3 2.6 3.6 3.1 0.20 12.5 820 S5 4.6 5.6 5.1 0.9 478 S4 3.6 4.6 4.1 0.20 13.2 S6 5.6 6.6 6.1 1.0 '576 820 S5 4.6 5.6 5.1 0.20 11 .1 S7 6.6 7.6 7.1 1.0 605 S6 5.6 6.6 6.1 0.30 14.3 S8 7.6 8.6 8.1 1.0 580 S7 6.6 7.6 7.1 0.20 13.1 S9 8.6 9.6 9.1 0.9 590 S8 7.6 8.6 8.1 0.30 14.5 S9 8.6 9.6 9.1 0.30 14.6

contained elevated concentrations of zinc with values of Zinc (Zn) 122 ppm and 127 to 340 ppm respectively. The concentration ofzinc in slurry slime in most of the test ponds varied between 39 to 81 ppm (Table 5). These Chromium (Cr) concentrations are close to the average val ue of zinc in the The concentration of chromium in slime in all the earth's crust, which is in the order of 10 1 ppm (Figure 2) eight ponds varied between 19 to 36 ppm (Table 5). These as well as that in the stream sediments in the Kuala Pilah va lues are below the average concentration of chromium ir - Gemas, Boundary Range, South Kelantan and Kenyir the earth's crust, which is in the order of 102 ppm (Figur Reservoir areas which varied between 29 - 43 ppm (Table 2). The stream sediments in the the Kuala Pilah - Gemas 2). However, the uppermost layer of slurry in Pond E814, Boundary Range, South Kelantan and Kenyir Reservoir and the layer of slime between 2.5 to 8.5m in Pond B81 were not analysed for chromium (Table 2).

Geological Society of Malaysia Annual Geological Conference 200 MINOR AND TRACE METALS IN SLURRY SLIME IN MINED-OUT PONDS IN THE KINTA VALLEY, PERAK 305

2 3 4 5 10_, 10-z 10-1 10°10 1 10 10 10 10 mo/kQ Tin (Sn) H • Slurry slime samples in seven of the ponds (B 141, He ~o ~------~------2 Li 0 Bl22, Bl27, B5 , E814, B72 and B20) contained between Be e B e 20 to 70 ppm of Sn (Table 5). These tin values are higher c • than the average concentration in the earth's crust (Figure N e 0 • 2) as well as that in the stream sediments in the Kuala Pilah F • Ne -o '------,.--- __ ,__-' 10 - Gemas, Boundary Range, South Kelantan and Kenyir Na • Mo • Reservoir areas (Table 2) which is in the order of 10° ppm. AI • Si e The concentration of tin values in Pond B81 were very p • s • high, varying between 140 to 240 ppm. Cl e Ar 0 ------,.---~------18 Tungsten (W) K e Ca e The content of Win six of the ponds [B141, B122, Sc 0 ~ 0 B 127, (except for a section between 1.8 to 2.8m depth), B5, v • B72 and B20] varied between 8 to 16 ppm (Table 5). These Cr • • ~ values are close to the average concentration of tungsten in Co e . the earth's crust (Figure 2) as well as that in the stream Ni e Cu • sediments in the Kuala Pilah - Gemas, Boundary Range, Zn e Ga 0 South Kelantan and Kenyir Reservoir areas (Table 2), which Ge 0 is in the order of 10° ppm. At depths between 2.5 to 8.5m As e Se e in Pond B81 and between 2.8 to 6.8m in Pond E814, the Br 0 Kr 0 ------__ ,__ ---36 concentrations of tungsten were slightly higher, with values Rb 0 Sr 0 varying between 28 to 60 ppm and 20 to 40 ppm y 0 Zr 0 respectively. Nb 0 Ma • Mercury (Hg) Tc 0 Ru 0 Rn 0 Slime in five ponds (B81, B 122. B5, B72 and B20) Pd e had 0.10 to 0.24 ppm of mercury (Table 5). The remaining Ag e Cd e three ponds (B 141, B 127 and E814) had higher I n 0 Sn e concentrations of mercury, varying between 0.26 to 0.54 Sb e Te e ppm. These concentrations of mercury (in all 8 ponds) are I • above the average concentration in the earth's crust (Figure Xe 0 1------1------54 Cs 0 2) as well as that in the stream sediments in the Kuala Pilah Ba 0 La 0 - Gemas, Boundary Range, South Kelantan and Kenyir Ce ~ 0 2 REE ~ 0 Reservoir areas (Table 2), which is in the order of 10- Hf 0 ppm. Ta 0 w 0 Re 0 Os e ATOMIC Antimony (Sb) lr 0 NUMBER The concentration of antimony in the eight test ponds Pt e Au 0 generally varied between 1 to 8 ppm (Table 5). However, Ho • T l e Pond B81 had slightly higher concentrations of antimony, Pb e Bi 0 with values between 9 to 14 ppm. The concentration of :o • e Known btologicol effects antimony in the slurry slime in all eight test ponds are R~ • ____ 0 Biological effects uncertain SG higher than the average concentration in the earth's crust, Fr e based on Krouskapf,1979 Ra e and Mo rkert, 1992 . which is in the order of I0- 1 ppm (Figure 2). However, the Ac e Th • concentration is close to that in the stream sediments in the Pa e Kuala Pilah - Gemas area which have a concentration of 2 u • 1 3 4 5 ppm (Table 2). 1C)3 1

June 2-3 2001, Pangkor Island, Malaysia 306 CHow WENG SuM

Table 5. Concentration oftrace metals in slurry slime.

Pond Sample Sample epth (m) Trace Melflls (pprn) No. No. From To Mid-point Mo Cu Zn Cr Sn w Hg Sb 8i Cd Pb Ni Co As S1 0.9 1.9 1.4 2.9 4 39 17 40 8 0.40 1 1 1 36 5 1 10 8141 S2 1.9 2.9 2.4 3.7 5 42 19 20 16 0.42 1 2 1 34 6 1 15 S3 2.9 3.9 3.4 3.4 7 55 23 20 8 0.44 1 2 1 56 9 3 10 S4 3.9 4.9 4.4 4.4 8 66 24 30 12 0.42 1 3 1 72 10 4 10 1.5 2.5 ~.u 4.~ ;jt) (~ U.1ti lU 10 1 ~~ 2.5 3.5 3.0 . 4.2 42 127 ~~ ~ri~ 2!!8 0.18 9 12 1 1~~ r4 ~ ~~ S3 3.5 4.5 4.0 4.3 71 310 34 200 40 0.12 10 12 2 165 30 8 100 881 S4 4.5 5.5 5.0 5.1 75 340 35 200 40 0.10 9 14 2 181 32 8 100 S5 5.5 6.5 6.0 4.2 67 280 32 240 60 0.12 9 18 2 167 25 7 150 S6 6.5 7.5 7.0 5.2 81 270 36 200 32 0.10 12 19 2 210 33 9 100 S7 7.5 8.5 8.0 5.2 76 250 34 240 60 0.14 14 21 2 230 29 6 200 ~.1 J.1 ~.ti 1!:1 0.22 1 4 1 tif ~~ 3.1 4.1 3.6 16 ~~ ~~ ~~ ~~ 1!!2 0.24 1 5 1 67 ~~ ~ ~~ 8122 S3 4.1 5.1 4.6 15 15 70 27 20 16 0.24 3 3 1 67 11 5 15 S4 5.1 6.1 5.6 15 15 71 25 40 12 0.22 1 2 1 66 11 5 20 S5 6.1 7.1 6.6 15 15 69 23 30 12 0.18 1 4 1 62 11 5 20 S6 7.1 8.1 7.6 12 12 68 23 40 16 0.18 1 1 1 63 11 5 20 l.tl ~.tl ~.;j l.tl 14 (';) ~1 {';) 1~ 1';) 4U ~4 ti s~ 2.8 3.8 3.3 2.4 14 73 21 40 ~~ K~~ l ~ 75 12 7 10 S3 3.8 4.8 4.3 2.5 13 73 22 20 16 0.28 6 10 1 76 11 6 10 8127 S4 4.8 5.8 5.3 3.1 12 70 20 30 16 0.26 4 8 1 74 11 7 10 S5 5.8 6.8 6.3 3.2 12 76 21 40 16 0.28 5 3 1 71 12 7 10 S6 6.8 7.8 7.3 2.6 12 72 19 35 12 0.34 5 3 1 69 10 6 10 S7 7.8 8.8 8.3 2.6 13 66 19 30 12 0.32 4 1 1 69 11 6 10 S8 8.8 9.8 9.3 2.7 12 70 19 20 8 0.34 4 5 1 70 11 6 15 2.1 2.0 121.!! ~u ~u lZ U.1tl ';) 4 1 4 ~~ 3.1 ~:~ 3.5 3.5 ~~ ~~ 20 8 0.22 1 4 1 ~~ ~ 4 ~~ 85 S3 4.1 5.1 4.5 3.6 9 65 23 20 8 0.20 2 4 1 61 9 4 10 S4 5.1 6.1 5.5 3.5 8 56 21 20 8 0.20 1 4 1 65 8 4 10 S5 6.1 7.1 6.5 3.3 8 57 20 30 8 0.20 3 4 1 56 8 4 10 S6 7.1 8.1 7.5 3.5 8 60 20 30 8 0.22 4 2 1 61 8 3 10 S7 8.1 9.1 8.5 3.3 8 58 20 30 6 0.22 3 2 1 60 8 3 10 1.!! 2.!! 2.3 4.4 JU 1~~ ~1 ru ~u U.;jti tl 1 1 ts!:l 21 E814 ~~ 2.8 3.8 3.3 4.1 20 81 19 40 40 0.54 4 1 1 65 21 ~ ~~ S3 3.8 4.8 4.3 4.1 20 79 19 40 24 0.54 2 3 1 65 21 8 10 S4 4.8 5.8 5.3 3.4 21 81 19 40 24 0.54 5 2 1 66 20 8 10 u.o 1.0 1.1 J.ti 14 titi ~1 tiU lU u.~2 1 ti 1 1U s~ 1.6 2.6 2.1 3.6 13 62 20 60 10 0.22 1 6 1 ~~ n : 10 S3 2.6 3.6 3.1 3.4 12 59 19 50 8 0.22 1 6 1 70 10 4 15 872 S4 3.6 4.6 4.1 2.9 13 69 20 40 8 0.24 1 6 1 76 10 5 20 S5 4.6 5.6 5.1 3.2 12 62 22 40 2 0.20 1 3 1 79 10 4 15 S6 5.6 6.6 6.1 3.5 11 60 18 30 8 0.18 3 2 1 76 8 4 15 S7 6.6 7.6 7.1 3.3 11 57 18 40 8 0.18 2 4 1 73 9 4 25 ::i1 U.ti 1.0 1.1 2.0 11 tiU lf ;jU ts U.12 1 4 1 S2 1.6 2.6 2.1 2.8 13 62 17 30 8 0.12 1 4 1 ~~ ~ : ~ S3 2.6 3.6 3.1 3.0 13 62 17 35 8 0.14 1 4 1 58 9 4 10 S4 3.6 4.6 4.1 3.4 14 62 18 35 12 0.14 1 4 1 62 10 5 10 820 S5 4.6 5.6 5.1 3.0 16 63 17 40 8 0.12 3 6 1 60 10 4 15 S6 5.6 6.6 6.1 3.4 17 68 20 50 12 0.18 3 6 1 64 10 6 20 S7 6.6 7.6 7.1 3.1 18 76 22 50 8 0.16 3 5 1 69 13 6 20 S8 7.6 8.6 8.1 3.3 18 76 23 60 16 0.18 3 6 1 70 14 6 20 S9 8.6 9.6 9.1 3.3 19 78 23 60 16 0.18 3 6 1 70 14 6 15 concentrations are above the average in the earth's crust, earth's crust which is in the order of 10·1 ppm (Figure 2). which is in the order of 10· 1 ppm (Figure 2) as well as that in the stream sediments in the Kuala Pilah - Gemas area Lead(Pb) which have a concentration of 1 ppm (Table 2). The concentration of the lead in slurry slime in almost all the ponds varied between 34 to 89 ppm except for Pond Cadmium (Cd) 81 where the concentration of lead was relatively higher, The concentration of cadmium in slurry slime in almost with values· between 89 to 230 ppm (Table 5). These all the test ponds was fairly constant with a concentration concentrations are within the average in the earth's crust, of 1 ppm except for Pond B81 where between a depth of which is in the order of 10 1 ppm (Figure 2) and close to that 3.5 to 8.5m, the concentration of the cadmium was 2 ppm in the stream sediments in the Kuala Pilah - Gemas, (Table 5). These concentrations (i.e. 1 to 2 ppm), are Boundary Range, South Kelantan and Kenyir Reservoir relatively higher than the average concentration on the areas which varied between 14 to 19 ppm (Table 2).

Geological Society of Malaysia Annual Geological Conference 2001 MINOR AND TRACE METALS IN SLURRY SLIME IN MINED-OUT PONDS IN THE KINTA VALLEY, PERAK 307

Nickel (Ni) the trigger or threshold concentrations are regarded as uncontaminated. On the other hand, soil samples with The concentration of nickel in the slurry slime in six concentrations of elements/metals exceeding the trigger of the ponds (Bl27, B5, B72, B20, Bl41, Bl22) varied and threshold concentrations should be considered as toxic, between 5 to 14 ppm (Table 5). The remaining two ponds particularly to agricultural practices and some remedial (B81 and E814) had higher concentrations of nickel. At a action has to be implemented. depth between 3.5 to 8.5m in Pond B81, the slurry slime It was observed that the concentrations of cadmium, contained 25 to 33 ppm of nickel. Pond E814, likewise, had chromium, lead, mercury, copper and nickel in the slurry relatively higher concentrations of nickel, with values slime were well below the trigger concentrations (of English between 20 to 21 ppm. These concentrations are of similar Standards) and the threshold values (of European quantum as the average in the earth's crust which is in the Standards). order of I0- 1 ppm (Figure 2), but are slightly higher than However, arsenic from slurry slime in Pond B81 were those in the stream sediments in the Kuala Pilah - Gemas high, varying between 25 to 200 pm and are above the Boundary Range, South Kelantan and Kenyir Reservoi; trigger concentrations and threshold values. The areas where 2.8 to 5.0 ppm of Ni were recorded (Table 2). concentration of arsenic in slurry slime in certain sections Cobalt(Co) of the profile in the remaining seven ponds were marginally above the trigger concentrations (Table 6). The concentration of cobalt in slurry slime in all the The concentration of zinc in the slurry slime in seven eight ponds varied between 1 to 9 ppm (Table 5). These ponds (B141, B122, Bl27, B5, E814, B72 and B20) were concentrations are lower than the average in the earth's well below the trigger concentrations. However, in Pond crust, which is in the order of 10 1 ppm (Figure 2). However, these concentrations are almost similar to that in the stream B8l, slurry slime from a depth of 3.5 - 5.5m had high sediments in the Kuala Pilah - Gemas, Boundary Range, concentrations of zinc which were above the trigger South Kelantan and the Kenyir Reservoir areas where there concentration of 300 ppm. Further down from 5.5- 8.5m are 3.7 - 5.0 ppm of cobalt (Table 2). depth, the concentration of Zn (250 - 280 ppm) was very close to .the trigger concentration. Arsenic (As) The concentration of arsenic in slurry slime in almost DISCUSSION all the ponds (except for Pond B81) varied between 10 to 25 ppm (Table 5). In Pond B81, the concentrations of i) Slurry slime in Pond B81 contained relatively higher arsenic at a depth between 2.5 to 8.5m were relatively concentrations of minor, precious, radioactive and trace higher, varying between 40 to 200 ppm. These metals (except for mercury, cobalt and cadmium) as concentrations are slightly higher than the average in the compared to that in the other seven ponds. earth's crust, which is ih the order of 10° ppm (Figure 2) Elevated concentrations of manganese (501-792 ppm), as well as that in the stream sediments in the Kuala Pilah iron (2.0 to 2.6 %), uranium (21 ppm), nickel (25-33 - Gemas, Boundary Range, South Kelantan and the Kenyir ppm), zinc (127-340 ppm), tungsten (28-60 ppm), lead (80-230 ppm), arsenic (40-200 ppm), silver (0.5 to 1.0 Reservoir areas where ~.0 to 8.0 ppm of arsenic were present. ppm), copper (36-81 ppm), tin (140-240 ppm), antimony (9-14 ppm) and bismuth (12-21 ppm) were present within certain sections of the slurry slime profile HEAVY METAL TOXICITY in Pond B81. This trend is also reflected in the pond Rowell (1994) had suggested that high concentrations water tested earlier (Chow, 1988) where the of zinc, copper, nickel and boron had direct effects on the concentration of arsenic, iron, manganese were also growth of crops. Other elements/metals like cadmium, lead, relatively high and the water was slightly more acidic mercury, molybdenum, selenium, chromium and fluorine with a pH of 6.1. The pattern is a reflection of the source material. Pond ~re non-toxic to crops but they may affect animals feeding m the crops grown over soils which contain high B81 has limestone-schist bedrock very near to the concentration of the elements/metals. granite contact. It is likely that the contact zone is In England, the concept of "trigger concentrations" mineralised and the slime is in part, derived from these (ICRCL, 1987) which is directly related to the intended use mineralised soils. of a site, has been introduced to determine the maximum (ii) Some of the other seven ponds had elevated concentration of contamination allowable in a site. In concentrations of certain metals at certain depths. Europe, the concept of "threshold concentration" (Wild, Pond E814 had elevated concentrations of manganese 1993) which addresses the same problem, albeit on a less (577-629 ppm), mercury (0.36-0.54 ppm) and nickel stringent level, is adopted. The limits of trigger concentration (20-21 ppm) for the entire slurry slime profile and zinc and threshold concentration are given in Table 6. Soil ( 122 ppm) between 1.8 to 2.8m depth. samples having concentrations of elements/metals below Pond Bl27 had elevated concentrations of mercury (0.26-0.34 ppm) between depths of 1.8 to 9.8 m and June 2-3 2001, Pangkor lsland, Malaysia 308 CHow WENG SuM

Table 6. Trigger concentrations and threshold values for selected inorganic contaminants (after ICRCL, 1987).

Contaminants Planned Uses Trigger Concentration, !Jg/g fair( !dried soil), Threshold Group A: Contaminants which may pose hazards to health Arsenic (As) Domestic gardens, allotments, parks, playing field, open space [10], (40) Cadmium (Cd) Domestic·gardens, allotments, parks, playing field, open space [3], (15) Chromium (Cr) Domestic gardens, allotments, parks, playing field, open space [600], (1,000) Lead (Pb) Domestic gardens, allotments, parks, playing field, open space [500], (2,000) Mercury (Hg) Domestic gardens, allotments, parks, playing field, open space [1], (20) Group B: Contaminants which are phytotoxic but not normally hazards to health Boron (B) Any uses where plants are to be grown 3 Copper (Cu) Any uses where plants are to be grown 130 Nickel (Ni) Any uses where plants are to be grown 70 Zinc (Zn) Any uses where plants are to be grown 300 Selenium (Se) Domestic gardens, allotments, parks, playing field, open space [3], (6)

Table 7. Distribution trend of metals in slime-slurry profile.

Pond No. Mining Concentration of metals increasing with the Concentration of metals decreasing with the Concentration of metals which remain Method depth of the slurry slime profile depth of the slurry slime profile almost constant in the slurry slime profile

881 Palong Ni, Pb, Mo, Cu, Zn, Cr, Sn, W, Co, 8i, As, Hg Cd Sb, Fe, Mn, Ag, U

820 Palong Ni, Pb, Mo, Cu, Zn, Cr, Sn, W, Co, 8i, As, . Cd Sb,Fe,Mn,Ag,Hg,U

8141 Palong Ni, Pb, Mo, Cu, Zn, Cr, W, Co, 8i, Fe, Mn, Sn Sb,As,Cd Ag,Hg, U

8127 Dredging Mo,Sb,Hg, U Ni, Pb, Sn, W, 8i, Cr, Zn, Cu As,Co,Cd,Ag,Mn,Fe

872 Palong Pb,As,Ag,Sb,U Ni, Sn, W, 8i, Mn, Fe, Hg, Cr, Cu, Zn, Mo Co,Cd

E814 Palong 8i, W,Mn,Hg Ni, Sn, Fe, Cr, Cu, Zn, Mo, Pb, Ag, U, Sb, As Co,Cd

8122 Dredging W,Ag,U Ni, Sn, Fe, Cr, Cu, Zn, Mo, Pb, Mn, 8i, Hg, Co, As, Sb, Cd

85 Dredging Sn,Hg Pb, Mo, Cu, Zn, Cr, W, Sb, Fe, Mn, Ag, U Ni, Co, 8i, As, Cd

bismuth (8-14 ppm) between 1.8 to 5.8 m. iv) Ponds Bl27, B122 and B5, which are left-overs of the Pond B20 had relatively high manganese concentrations dredging method of mining have a pattern similar to of 576-605 ppm between 5.6 to 9.6 m depth. that of Ponds B72 and E814, that. is, the concentrations Pond B 141 had relatively high mercury values of 0.40 of most metals (except for tungsten, silver, uranium, to 0.44 ppm between depths of 0.9 to 4.9 m. cobalt, arsenic, antimony and cadmium in B122, and It is likely that the relatively high concentrations of tin, mercury, nickel, cobalt, bismuth, arsenic and these metals (i.e. manganese, mercury, bismuth and cadmium in B5 and molybdenum, antimony, mercury, nickel) in the slurry slime in these ponds are attributed uranium, arsenic, cobalt, cadmium, silver, manganese to the inherent composition of the original soil. and iron in B 127) decreased as the depth of the slurry­ (iii) Almost all the metals in the slurry slime in Ponds B20 slim~ profile increased (Table 7). (except for cadmium), B81 (except for mercury, v) Most of the slurry slime samples contain higher cadmium) and B 141 (except for tin, antimony, arsenic concentrations of uranium and other trace heavy metals and cadmium), showed an increase in concentration as such as tin, mercury, antimony, bismuth and cadmium the depth of the slurry slime profile increased (Table 7). as compared to that in the earth's crust or stream Ponds B72 and E814 showed a different pattern where sediments. A survey should be carried out to check the the concentration of most of the metals (except for level of radioactivity emissions from the slurry slime. lead, arsenic, silver, antimony, uranium, cobalt and cadmium in Pond B72 and bismuth, tungsten, CONCLUSION manganese, mercury, cobalt and cadmium in Pond E814) were relatively higher in the uppermost part of i) Slurry slime from Pond B81 should not be utilised for the slurry-slime profile, but the concentrations the construction of residential houses or used as fill decreased as the depth of the profile increased. material for the creation of domestic gardens, parks, All these five ponds are left overs of the palong mining playing fields as the concentration of arsenic in the method. slurry slime is above the trigger concentration and Geological Society of Malaysia Annual Geological Conference 2001 MINOR AND TRACE METALS IN SLURRY SLIME IN MINED-OUT PONDS IN THE KiNTA VALLEY, PERAK 309 threshold value. The concentration of arsenic in slurry REFERENCE slime from certain sections of the remaining seven ponds are marginally above the trigger concentration ABDUL, H. ET AL., 1995. Geochemical Exploration Of The Kuala and it would be best to blend it with some other low Pilah - Gemas Area, Negeri Sembilan. Geological Survey Unplublished Report EMR l/95. arsenic-bearing slurry slime before being utilised as CHow, W.S., 1986. Geology And Mineral Resources OfThe Gunung fill material. Gajah Terom Area, Sheet48. Geological Survey Unpublished As slurry slime from Pond B81 also contained high Report (in manuscript). concentrations of zinc, it should not be used for the CHow, W.S., 1998. Studies Of Slurry Slime In Mined-out Ponds, planting of crops. Kinta Valley, Peninsular Malaysia, For Purposes Of The concentrations of toxic metals in the slurry pond Reclamation. Ph. D Thesis, University of Malaya. in the remaining seven ponds are well below the trigger CHu, L.H. ET AL., 1982. Regional Geochemistry Of South Kelantan. concentrations and threshold values and can be used as Geological Survey Geochemical Report l. fill material for the development of domestic gardens, CHu, L.H. ET AL., 1986. Regional Geochemistry Of The Boundary Range Area. Geological Survey Geochemical Report 1. parks, playing fields as well as for the planting of DARNLEY, A.G. ET AL., 1995. A Global Geochemistry Database Of crops. Environment And Resource Management. Final Report of ii) Slurry slime in Pond B81 contained elevated IGCP Project 259. concentrations of precious, radioactive, minor and trace ICRCL (INTERNATIONAL CoMMITTEE FoR REDEVELOPMENT OF metals (except for mercury, cobalt and cadmium) as CoNTAMINATED LAND), 1987. Guidance In The Assessment compared to the norm in the crustal rocks and stream And Redevelopment Of Contaminated Land. ICRCL 59/83, sediments. 2nd Edition. CDEPIEPTS Department Of Environment, The limestone-schist bedrock of the mine-pit is very London. close to the granite contact and it is likely that the GSD (GEOLOGICAL SuRVEY DEPARTMENT), 1981. A Manual Of contact zone near the mine is highly mineralised. Geochemistry Exploration Methods. Geological Survey Special Page 3. iii) Data on the concentration of precious, radioactive, RoWEL, D.L., 1994. Soil Science Methods and Applications. minor and trace metals in the slurry slime is a useful Longman Scientific and Technical, United Kingdom. baseline reference for environmental auditing especially for the development of industrial parks in the vicinity of the eight ponds studied.

June 2-3 2001, Pangkor Island, Malaysia