-Koduah Owusu Ansah

-Ana Gonzalez

Phytoremediation Potential of Bermudagrass

and Vetivergrass on Arsenic Pollutants at Obuasi Minetailings

in Ghana

1

Geographic Location

2

About Ghana

Ghana is Africa's second-largest gold producing country after South Africa

Close to 60 million ounces of gold have been mined in Ghana over the last century

Gold reserves and resources are estimated at well over 100 million ounces

Mining industry contributes approximately 40% of Ghana's gross export earnings

3

Gold and Culture Ashanti King

Gold and Culture4

History of Obuasi(Underock) Gold Mine

Gold mining at Obuasi began in 1898 by private businessmen.

Before 1957 -Ghana was originally called Gold Coast or the Land of Gold

Gold has been part of the culture and history of the country

Gold mining is the largest foreign exchange earner, contributing about 45% of the country’s total foreign currency.

Obuasi Gold Mine5

Company has been purchased by Anglogold –

a worldwide conglomerate company

with over 2 million shares It can be considered as

the single industrial hub of the Ghanaian economy.

Gold ore at site consists of pyrites(FeS) and

Arsenopyrites(FeAsS)

Obuasi Gold Mine6

Basic Information

Arsenic (As) can be present in soils, air and water as a metalloid and as a chemical compound in both organic and inorganic forms.

Arsenic ranks 20th in abundance of elements in the earth’s crust, 14th in seawater and is the 12th most abundant element in the human body.

Despite its abundance, it is one of the most toxic elements encountered in the environment. (Arsenite and Arsenate)

Arsenic7

Arsenic8

Trail of destruction

Due to roasting of Arsenopyrites and

pyrites ores into the atmosphere. Golow, AA et al Process water from plant discharge into

nearby rivers and creeks Tailings rich in Arsenic left to be rain

washed into pristine areas and rivers

9 Arsenic

Levels of pollution

10 Arsenic

Both, the United States Environmental Protection Agency (US-EPA) and the World Health Organization (WHO) have established the As level for drinking water at 10 μg/ L Unfortunately, some developing countries still use the old standard of 50 μg/ L, primarily because of economical factors that prevent access to new technologies.

11 Arsenic

Risks Associated with Arsenic

Several types of cancer (skin, stomach, lung) skin pigmentation, respiratory infections, causes high infant mortality rate etc. Hearing and vision impairment, keratosis, edema, gangrene, liver damage, etc.

Arsenic pollution has been a problem in Ghana, Zambia, Tanzania, Taiwan, Bangladesh, Latin America and China

Most toxic was the Pompora Treatment –shut down a couple of years ago. Dodoo, DK et al

Arsenic12

Arsenic Pollution

Arsenic13

Arsenic14

Objectives of the Proposal

Test the selected species, Vetiver Grass and Bermuda

Grass, using greenhouse study and later on site. Determine if any amendments are needed and

consider the possibility of genetically enhancing the plants.

Remove arsenic pollution with the use of the selected species down to a level which is considered safe for humans.

Monitor the concentration of arsenic periodically to make sure mining activities don’t cause a recurrent problem

Objectives 15

Why consider this research? Most research work carried out on rock

formations, effect of Arsenic pollution and risk assessments - Smedley et al, Golow et al, Amonoo-Niezar et al.

United Nations curative health initiative. No research work on Environmental

restoration using Phytoremediation known so far- which is cheaper and affordable.

16

Species Selection Bermudagrass( Cynodon dactylon)- a C₄ Warm season

grass spp. Very adaptable to Warm not very humid conditions in

that part of the world. (Native to area)- Drought tolerant

Easy to propagate- rhizomatous Highly tolerant and phytoaccumulator of Arsenic.

Madejon, P. et al, Weaver, R W et al,

17 Species

Vetiver Grass

Species

Vetivera Zizanioides

MORPHOLOGY OF VETIVER• Vetiver belongs to the Poaceae family,

originated from Indian sub continent, but can be found throughout tropical and subtropical regions of Africa, Asia, South and North Americas and Mediterranean Europe. Maffei, et al. 2002

• It’s leaf is 45-100cm long and 0.6-1.2cm wide- has a smooth and waxy leaf texture

• Fast growing perennial grass, a long (3-4m) fast massive and complex root system and can penetrate to deeper layers of soil.

• 1yr old Vetiver grass can produce 1meter long roots.

18

Vetiver Grass

Phytoremediation

• Roots can grow a total length of 7meters in 36 months after planting. Lavania et al 2003

• Extensive root system support plant under severe drought and withstand high velocity subterranean flow.

• Extensive root system can scavenge for pollutants and sterile under growing conditions. Produces not seeds

• Has stiff and erect stems up to 2m high Truong, 2002

19

Resistance to Herbicides

Phytoremediation

Vetiver cells are 170-fold resistant to glugosinate compared to susceptible cells

The glutamine synthethase activity of resistant cells was twice as high as susceptible cells

20

Physiological Characteristics

Phytoremediation

• Adaptable to extreme environmental conditions. Truong, 1999a.

• Can tolerate a time of submergence (more than 120 days). Much higher than Bahiagrass-60-70 days: Carpetgrass-32-40 days: sour Paspalum-25-32 days: St. Augustine grass- 18-32 days and Centipede grass- only 7-10 days

• It can survive more than 3 mts under muddy water.• Has an average net biomass of more than 100 tons of dry

matter per year. Truong 2003

21

Physiological Characteristics

Adaptable to extreme environmental conditions. Truong, 1999a.

Can tolerate a time of submergence (more than 120 days). higher than Bahiagrass:60-70d, Carpetgrass: 32-40d, sour Paspalum: 25-32d, St. Augustine grass- 18-32d, and Centipede grass: 7-10 days

It can survive more than 3 mths under muddy water.

Has an average net biomass of more than 100 tons of dry matter per year. Truong 2003

Phytoremediation 22

Phytoremediation potential of Bermudagrass Native Species

Bermudagrass has been used as a phytoextraction potential spp. for Cu in Zaire (Katanga Region) Shucta et al 2010

Bermudagrass has also been used for Arsenic and Mercury hyperaccumulation research. Weaver et al 1984

Phytoremediation 23

Bermudagrass

Phytoremediation 24

Bermudagrass

Species

Cynodon dactylon

MORPHOLOGY• Native to north and east Africa,

Asia, Australia and southern Europe.

• The name "Bermuda Grass" derives from its abundance as an invasive species on Bermuda.

25

Bermudagrass

Species

• It has a deep root system; in drought situations with penetrable soil, the root system can grow to over 2 m deep.

• It is fast growing and tough.

• The blades are a grey-green colour and are short, usually 2–15 centimetres (0.79–5.9 in) long with rough edges. The erect stems can grow 1–30 centimetres (0.39–12 in) tall.

26

27 Goldmine

28 Goldmine

Contrasts29 Goldmine

Contrasts

30 Goldmine

Experimental Plan

31 Plan

3 replications: 1-3 concentrations of As (10mg/kg 15mg/kg and 20mg/kg for each sp.

3 replications of arsenic(10/15/20mg/kg plus 20mmol NTA chelating agent for each replication.

Six controls – We shall use conetainer containers for the trials

Clippings to mimic herbivory, and conduct bioassay.

Results will be applied to the field.

32

Phytoremediation- Best alternative option

Phytoremediation is the use of plant based system to remediate contaminated soils

Cheap, affordable and environmental friendly

In situ application Laboratory and Field

research work on Arsenic in Minetailings Smits, Pilon et al, Moreno-Jimenez J et al.

33Phytoremediation

Conclusions

Companies need to take responsibility for the repercussions caused by their activities. Prepare risk assessment plans and contingency measures for cases such as this one.

Phytoremediation is the best solution for pollution control in developing countries, considering government regulations, technology limitations and poverty.

The selected species are great options because of their fast growth, deep roots, pollutant tolerance and economic value.

NGOs can be considered as a good option for funding and managing a project such as this one.

34

References

1. Smedley PL (1996) Arsenic in rural groundwater in Ghana. J Afr Earth Sci 22:459-4702. Ma, L.Q.; Tu, M.S.; Fayiga, A.O.; Stamps, R.H.; Zillioux, E.J. (2004) Phytoremediation of Arsenic-

Contaminated Groundwater by the Arsenic Hyperaccumulating Fern Pteris vittata L. Int. J. of Phytoremediation 6(1): 35-47.

3. Tripathi, R.D.; Srivastava, S; Mishra, S.; Singh, N.; Tuli, R.; Gupta, D.K.; Maathuis, J.M. (2007) Arsenic hazards: strategies for tolerance and remediation by plants. Sci. Direct. 25: 158-165.

4. Rofkar, J.R.; Dwyer, D.F.; Frantz, J.M. (2007) Analysis of Arsenic uptake by Plant Species Selected for Growth in Northwest Ohio by Inductively Coupled Plasma-Optical Emission Spectroscopy, Communications in Soil Science and Plant Analysis, 38:17, 2505-2517

5. Garvin, T.; McGee, T. K.; Smoyer-Tomic, K.E.; Aubynn, E. A. (2009) Community-company relations in gold mining in Ghana, Journal of Environmental Management, 90:1, 571-586

6. Luu T. D. ;Truong, P.; Mammucari, R.; Tran, T.; Foster, N. (2009) Vetiver grass, vetiveria zizanioides: a choice plant for phytoremediation of heavy metals and organic wastes. International Journal of Phytoremediation, 11:8, 664-691.

7. Golow, A.A.; Schlueter, A.; Amihere-Mensah, S.; Granson, H.L.K.; Tetteh, M.S. (1996) Distribution of Arsenic and Sulphate in the Vicinity of Ashanti Goldmine at Obuasi, Ghana, Bull. Environ. Contam. Toxicol, 56:703-710.

8. Eisler, R.; (2004) Arsenic Hazards to Humans, Plants, and Animals from Gold Mining, Rev Environ Contam Toxicol, 180: 133-165.

9. Akabzaa, T.M.; Banoeng-Yakubo, B.K.; Seyire, J.S. Impact of Mining activities on Water Resources in the Vicinity of the Obuasi Mine.

10. Adomako, E.E.; Deacon, C.; Meharg, A.A.; (2010) Variations in Concentrations of Arsenic and Other Potentially Toxic Elements in Mine and Paddy Soils and Irrigation Waters from Southern Ghana, Water Qual Expo Health, 2:115-124.

35

References

11. Bakker, J.P. (2002) Arsenic and Old Plants, New Phytologist, 156:1-8.12. Weaver, R.W.; Melton, J.R.; Wang, D.; Duble, R.L. (1984) Uptake of Arsenic and Mercury from Soil by

Bermudagrass Cynodon Dactylon, Environmental Pollution, 33:133-142.13. Obiri, S.; Dodoo, D.K.; Okai-Sam, F.; Essumang, D.K. (2006) Cancer Health Risk Assessment of

Exposure to Arsenic by Workers of AngloGold Ashanti-Obuassi Gold Mine, Bull. Enviroon. Contam. Toxicol., 76:195-201.

14. Ahmad, K.; Carboo, D. (2000) Speciation of As(III) and As(IV) in some Ghanain Gold Tailings by a Simple Distillation Method, Water, Air and Soil Pollution, 122: 317-326.

15. Moreno-Jimenez, E.; Esteban, E.; Fresno, T.; Lopez de Egea, C.; Penalosa, J.M. (2010) Hydroponics as a valid tool to assess arsenic availability in mine soils, Chemosphere, 79: 513-517.

16. Angin, I.; Turan, M.; Ketterings, Q.M.; Cakici, A. (2008) Humic Acid Addition Enhances B and Pb Phytoextraction by Vetiver Grass (Vetiveria Zizanioides), Water Air Soil Pollut, 188: 335-343.

17. Otirz Escobar, M.E.; Hue, N.V.; Cutler, W.G. Recent Developments on Arsenic: Contamination and Remediation.

18. Peterson, M.M.; Horst, G.L.; Shea, P.J.; Comfort, S.D. (1998) Germination and seedling development of switchgrass and smooth bromegrass exposed to 2,4,6-trinitrotoluene, Environmental Pollution, 99:53-59.

19. Clayton, W.D.; Hepper, F.N. (1974) Computer Aided Chrology of West African grasses, Springer, 29:213-234.

20. Asante, K.A.; Agusa, T.; Subramanian, A.; Ansa-Asare, O.D.; Biney, C.A.; Tanabe, S. (2007) Contamination Status of Arsenic and other trace elements in drinking water and residents from Tarkwa, a historic mining township in Ghana, Chemosphere, 66:1513-1522.

21. Truong, P.(2000) Application of the Vetiver System for Phytoremediation of Mercury Pollution in the Lake and Yolo Counties, Northern California, Pollutions Solutions Seminar.

36