Energy Dispersive X-ray Fluorescence Analysis of Mine Waters from the Migori Gold Mining Belt in Southern Nyanza,Kenya
O.B.Odumo •A.O.Mustapha •J.P.Patel •
H.K.Angeyo
Received:6January 2011/Accepted:2June 2011/Published online:17June 2011ÓSpringer Science+Business Media,LLC 2011
Abstract Analys of water samples from Mikei,Osiri,Masara and Macalder (Makalda)gold mines of the Migori gold mining belt of Southwestern Kenya were done to determine the level of heavy metals using the Energy Dis-persive X-ray Fluorescence technique.The concentrations of the heavy metals were;copper (29.34±5.01–14,975.59±616.14l g/L);zinc (33.69±4.29–683.15±32.93l g/L);arnic (958.16±60.14–18,047.52±175.00l g/L)and lead (19.51±5.5–214.53±6.29l g/L).High levels of arnic and lead were noted.The heavy metals are not only dangerous to the lives of miners and the local inhabitants;they are also a threat to aquatic life since the waters finally find their way into Lake Victoria.
Keywords ED-XRF ÁHeavy metals ÁGold mining ÁMine water
A number of studies conducted in gold mining ,in the Witwatersrand have produced increasing evidence that mines frequently contaminate adjacent environment with heavy metals,salts and radionuclides,(Bowell et al.1995).
Heavy metals are of particular interest for a number of reasons;firstly they show a tendency to accumulate in the diments and the soils,have a long persistence time and are non biodegradable.Secondly,they are ubiquitous in diments and soil arising from both natural and anthro-pogenic sources with pathways including inheritance from the parent rocks,application of water as well as local and long range atmospheric and fluvial deposits of emissions from dust and mining (Deb et al.2008).While in com-mercial mining there are some measures of environmental control,in artisanal mining there are no control measures and the mining environment is littered with tailings,overburdens and open pits.
Trace amounts of metals can be found in minerals constituting mineralized rocks.The size reduction process like crushing,during ore processing increas the surface area of the reaction of rock/mineral particles thereby accelerating oxidation and/or chemical weathering and hence the relea of metals (Getaneh and Alemayehu 2006).Many of the metals are esntial at low concentra-tions for plants,animals and human health but at higher concentration they can be toxic.In
some cas the con-centration of metals in different environmental media can exceed the maximum tolerable concentration and can cau harm to life;a number of ca histories have been docu-mented and reported from different parts of the world (Getaneh and Alemayehu 2006).hist
Due to the prence of gold and copper,we expected many heavy metals to be associated with the artisanal gold mining activities in the Migori gold mining belt as reported elwhere in the world (Getaneh and Alemayehu 2006;Ogola et al.2002;Serfor-Armah et al.2006;Veiga and Hinton 2002;Weast 1968).This study was therefore meant to asss accumulation of heavy metals in the mine waters in the Migori gold mining belt and make relevant
O.B.Odumo (&)ÁJ.P.Patel ÁH.K.Angeyo Department of Physics,University of Nairobi,P.O.Box 30197-00100,Nairobi,Kenya e-mail:******************.ke J.P.Patel
e-mail:****************.ke H.K.Angeyo
e-mail:*******************.ketelent
A.O.Mustapha
Department of Physics,University of Agriculture Abeokuta,2240Abeokuta,Nigeria
e-mail:******************.ke
Bull Environ Contam Toxicol (2011)87:260–263DOI 10.1007/s00128-011-0332-x
recommendations to the miners,the local populace and government authorities .
Materials and Methods
Eleven water samples were collected from Osiri,Macalder (Makalda),Mikei and Masara gold mines for heavy metal analysis.Ten of the eleven water samples were collected from panning ponds dug in the ground near the crushing sites,one each from Masara,Osiri A and Macalder.Three and four water samples,respectively were collected from Osiri B and Mikei,the eleventh sample was collected from one of the freshly dug mines at Mikei.At each sampling point,the bottles were rind at least three times with the water before taking the sample by immersing the bottle to about 10cm below the water surface.The samples were tightly aled and brought to the Nuclear Institute of Sci-ence and Technology,University of Nairobi for analysis.One hundred mL of each water sample was precon-centrated by adding Nitric acid,where the pH went below 3.5;ammonium solution was added to adjust it upwards.Two mL of 1%ammonium-1-pyrolidonedithiocabomate (APDC)solution was then added to the preconcentrate before stirring for about 30min,this was followed by suction filtration ove
r a 0.45l m nuclear pore filter paper (47mm in diameter)and left to dry.
Although there are many X-ray fluorescence techniques,the energy dispersive X-ray fluorescence (ED-XRF)tech-nique was preferred for this analysis becau it offers non destructive and reliable multi-elemental analysis capabil-ity.This technique also requires little sampling and sample preparation.The ED-XRF spectrometer ud in this study
consisted of a X-ray generator as the excitation source operated at 35V and 20mA;Canberra Si (Li)detector,an ORTEC spectroscopy shaping amplifier model 571,OR-TEC high voltage supply bias model 475,ORTEC liquid nitrogen monitor and a Canberra multichannel analyzer (S-100)interfaced with a 486channel personal computer.Each filter was run for 500s and the spectra collected by the Canberra detector with energy resolution of 195eV for (Mn-K a )X-rays at 5.9keV.The characteristic X-ray spectra obtained from the samples was evaluated by non-linear least squares fitting using the AXIL-QXA software.Figure 1shows a typical ED-XRF water spectrum obtained from the analysis.
prominentResult and Discussion
The levels and detection limits of chromium,mangane,Iron,cobalt,copper,zinc,arnic and lead are reported in Tables 1and 2,respectively,where copper,iron and magnesium were registered in all the s
amples collected.Concentration of cop-per ranged from 29.3±5.0–14,975.6±616.1l g/L.The average levels of copper at Mikei and Osiri B were 81.504and 31.377l g/L,respectively.Iron level ranged from 261.7±29.7–77,903.1±3,203.1l g/L.Zinc level at Osiri A was the lowest,33.7±4.3l g/L,while the highest level of 683.2±32.9l g/L was registered at Macalder panning pool.Average level of zinc of 183.2±13.2and 44.9±6.5l g/L were registered at Mikei and Osiri B,respectively.Abnce of gold and mercury were noted in all the mine waters.For mercury,this could be due to its high density that makes it ttle at the bottom of the pond with the
diments.
Fig.1Typical ED-XRF spectrum of a water sample
Arnic was detected in Macalder and Mikei samples,the highest level of 18,047.5±175.0l g/L was registered at Mikei,and this confirms the study by Odumo et al.(2011)that found the level of arnic t
o be higher in d-iments at Mikei.This level is high compared to results from Adola region of Ethiopia where its average was found to be 92.8l g/L (Deb et al.2008).However,the concen-tration is lower than 72mg/L registered at the Iron Duke mine in Zimbabwe (Williams and Smith 2000).Even though the miners don’t drink the waters directly,they u them to clean their hands before eating at the mines.Cows,goats and sheep also in many occasions especially during dry periods drink the waters.The situation is worned when this contaminated water find its way into the nearby rivers leading to direct domestic u by the locals since the rivers are their only source of water.The high level of arnic can be dangerous to the miners and their livestock since it is toxic to both animals and human beings.However,the high level of arnic should also be exploited if the concentration is economically viable since pure arnic metal is ud to produce crystalline gallium arnide which is a miconductor ud in computing and electronic industries.It can also be ud in agriculture,livestock and general industries (Winde and Sandham 2004).
Lead was also registered at higher levels from Mikei,this pos a threat to the lives of the miners since lead is a carcinogen.Other heavy metals like cobalt,mangane and titanium detected in some of the mines at low concentrations.
From this study,the concentration arnic,copper,zinc and lead in the Migori gold mine waters is high
and the miners should therefore be made aware of the con-quences of their exposure to them.The miners should be educated on the possible ways of protecting themlves from the exposure to the heavy metals.Proper procedure of disposal of the mine wasters should be followed to avoid further contamination of the environment.It is also sug-gested that a further study be carried out to verify the results of this study using other methods.Though con-tamination of the rivers in the area had been done,the
T a b l e 1E l e m e n t a l c o n c e n t r a t i o n i n w a t e r s a m p l e f r o m O s i r i ,M i k e i ,M a c a l d e r a n d M a s a r a (l g /L )
M a s 1
M a c 2
M i k 1
M i k 2
M i k 3
M i k 4
M i k 5
O s i -A
英语作文 求职信
O s i -B 1
O s i -B 2
O s i -B 3
E l e m e n t
T i
\30
112.9±5.1
46.5±11.3
207.5±24.9
\30
84.3±11.7
185.6±13.8
23.9±6.9
\30
\30
\30
C r
144.9±25.2
\25
22.4±7.5
69.4±12.5
39.2±8.5
30.2±9.9
48.1±11.3
receiver\25
\25
\25
\25
M n
339.8±5.7
35.0±8.5
\15
去痘食疗158.0±15.9
78.2±8.3
46.7±9.0
132.6±15.1
34.5±7.3
\15
\15
sampras29.0±8.2
F e
77,903.1±203.1
1,174.8±66.9
1,153.7±97.4
11,710.9±492.1
3,101.0±148.0
1,834.6±89.2
11,775.3±494.0
849.6±2.7
520.±40.6
261.6±29.7
360.5±32.7
C o
1,014.1±72.7
\10
\10
62.8±6.7
37.5±8.6
27.9±8.6
51.9±12.0
\10
\10
\10
\10
C u
14,975.6±616.1
45.3±6.7
93.0±9.5
113.6±7.7guess who batman
70.9±7.6
67.4±5.9
62.7±5.6
34.0±4.6
29.3±5.0
30.1±4.2
34.7±7.0
Z n
444.2±21.8683.2±32.9169.8±21.7291.3±16.1102.5±6.9
113.8±7.7238.3±13.933.7±4.356.5±4.3
34.1±6.9
44.0±8.4
A s
\2058.2±15.6
\20
958.2±60.11,184.4±78.818,047.5±746.04,058.9±175.0\20\20
\20
\20
P b 88.1±9.624.1±4.8
\10
200.9±13.1
214.5±16.3
19.5±5.5\10\10
\10
\10
\10
M a s M a s a r a ,M a c M a c a l d e r ,M i k M i k e i ,O s i O s i r i Table 2Detection limits in water samples (l g/L)
Element Detection limit Ti 30Cr 25Mn 15Fe
12Co 10Cu 8Zn 7As
数学学情分析20Pb
10
concentration of the metals should be investigated downstream.
Acknowledgments We thank the Department of Physics,Univer-sity of Nairobi,for funding this rearch.
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