THE AFRICAN NETWORK FOR THE CHEMICAL ANALYSIS OF PESTICIDES

(ANCAP)

 

 

 

 

 

 

 

REPORT OF THE SECOND ANCAP REGIONAL SYMPOSIUM, 2003

 

 

 

 

 

 

 

 

 

 

VENUE: DEPARTMENT OF CHEMISTRY

UNIVERSITY OF NAIROBI,

NAIROBI-KENYA

 

 

 

 

 

DATE: 17TH TO 19TH SEPTEMBER 2003


SUMMARY

 

 

The symposium was conducted from 17th to 19th September 2003. Participants of the symposium included all the participants of the workshop, and five others; namely: Dr Zachary M. Getenga (from Kenya), Prof Bernard Kiremire (from Uganda), Dr Negusie Megersa (from Ethiopia), Dr Leonia Henry, and Dr Michael Kishimba from Tanzania.

 

Many papers were presented during the symposium on different aspects of pesticide research conducted in the respective countries ranging from degradation, transport, to environmental assessment of the pesticide residues.

The symposium was crowned by a farewell party to the participants, and award of certificates of participation in the workshop.

 

ACKNOWLEDGEMENT

 

The ANCAP organising committee highly acknowledges the grant support from IPICS used for organising the workshop and symposium, for buying chemicals, consumables, and in facilitating the travelling and upkeep of participants from Ethiopia, Uganda, Tanzania and one upcountry Kenyan, who attended the symposium.


AFRICAN NETWORK FOR THE CHEMICAL ANALYSIS OF PESTICIDES (ANCAP) SYMPOSIUM

 

 

SEPTEMBER 17- 19, 2003, CHEMISTRY DEPARTMENT, UNIVERSITY OF NAIROBI, NAIROBI, KENYA

 

SYMPOSIUM PROGRAMME

 

WEDNESDAY, 17 SEPTEMBER 2003

 

SESSION 1

Chair: Prof. S. Wandiga

08:0009:00       Arrival, Introductions

09:0009:10       Introductory Remarks (Prof. S. Wandiga, ANCAP, Kenya)

09:1009:20       Welcoming Remarks (Prof. I.O Jumba, Chairman, Dept. of

Chemistry, University of Nairobi)

09.20-09;30        The African Network for Chemical Analysis of Pesticides: One

Year On      (Dr. M.A. Kishimba, Executive Secretary, ANCAP)

09.3010:15       Enhancement of biodegradation of persistent pesticides (Dr. Z.

Getenga, Maseno University)

10:1511:00       Group Photograph, Tea/Coffee Break

 

SESSION 2

Chair: Prof. B. Kiremire

11:0011.45       The Status of Pesticide Pollution in Tanzania - M.A. Kishimba,

University of Dar es Salaam

11.45 12.30     Pesticide Residues and Metabolite Levels in Zanzibar A.

Mmochi, IMS, University of Dar es Salaam

12:30-14:00        Lunch Break

 

SESSION 3

Chair: Dr. M.A. Kishimba

14.0014.45       Levels and Chemodynamics of Pesticide Residues in Southern

Lake Victoria and Its Basin (Dr. L. Henry, UDSM)

14.45-15.30        Advances in Liquid Membrane Technique for Selective Sample

Preparation in Environmental Analysis Dr. N. Megersa, AAU

15.30 16.15      Chemodynamics of Some Pesticide Residues in the Rufiji Delta,

Tanzania H. Mwevura, UDSM

16.00 16.30     TEA/COFEE BREAK/DISCUSSION

THURSDAY, 18 SEPTEMBER 2003

SESSION 4

Chair: Prof. B. Kiremire

 

09..00 10.00    Review of Pesticides Studies in Kenya (Prof. S. Wandiga,

UON)

10.00 10.45     Measurement of Extent of Biodegradation of Pesticides Dr. Z.

Getenga, Western University College of Science of

Technology

10.45 11.15     Tea/Coffee Break

SESSION 5

Chair: Prof. Kiremire

14.00 14.45    

14.45 15.15     15.15 16.00     Problems of Conducting Pesticide Research in

the Region - All

16.00 16.30     TEA/COFEE BREAK/DISCUSSION

FRIDAY, 19 SEPTEMBER 2003

SESSION 6

Chair: Prof. S. Wandiga

9.00 11.00           ANCAP COORDINATION BOARD MEETING

11. 11.30     COFFEE/TEA-BREAK

11.30 12.00           Way Forward: ANCAP Agenda, 2003/4

12.00 12.50           Discussion

12.50 13.00           CLOSING

12.30 14.30           LUNCH

 

 

 

 

 


ABSTRACTS

 

Shem O. Wandiga

Department of Chemistry

Colledge of Biological and Physical Sciences

University of Nairobi

P. O. Box 30197, Nairobi, Kenya.

Email: sowandiga@iconnect.co.ke

 

Abstract

 

Pesticides were first introduced into Kenya at the turn of the last century. They have been used for livestock and public health, agriculture and general household purposes. Several types of pesticides have been applied from time to time with their withdrawal rate depending on the onset of development of resistance by a particular pest.

Studies that have been undertaken in Kenya include determination of their residues in water, foods, sediments, aquatic weeds, fish, birds and animals resident within the lakes catchments, and Indian Ocean coast. The residue levels were found to be below the toxic concentrations but remained of concern for bioaccumulation through the food chain. Several examples of such studies were given.

 

 

Soil and water contamination by pesticides at Vikuge farm Kibaha: assessment of public health risk and remediation technologies

 

By

 

M.A. Kishimba

Chemistry Department,

University of Dar-es Salaam,

P.O. Boc 36061, Dar es Salaam

Email: kishimba@chem.udsm.ac.tz

 

Abstract

The paper assesses the risks to public health at Vikuge Village, Kibaha District Coast Region, Tanzania, where, in 1986, a 170 m3 donation of partially expired pesticides were stored in an open shed that eventually collapsed. Subsequent (in the year 2000) analyses of soil, sediment and water samples collected from the farm for pesticide residues revealed alarmingly high concentrations of pesticide residues in the soil and sediments; and levels above WHO maximum residue limits (MRLs) in drinking water during the rainy season. Most of the residues found in the soil at high concentrations were organochlorines, most being among the world banned persistent organic pollutants (POPs). The paper also assesses the various remediation technologies for pesticide-contaminated sites and recommends that bio- and phytoremediation methods be used for the decontamination of the soil and ecosystem restoration at Vikuge.

 

 

Bio-activation/remediation of 2,4-D and metribuzin in tropical soils

 

Madadi V. O.; Wandiga S. O; Jumba I. O.

Department of Chemistry,

Colledge of Bilogical and Physical Sciences

University of Nairobi, P.O. Box 30197, Nairobi, Kenya.

Email:madadivin2002@yahoo.com

sowandiga@iconnect.co.ke

ijumba@uonbi.ac.ke

 

 

Abstract

 

Environmental pollution is a gross and global issue that has risen concerned of experts in various fields. Attempts to stop further contamination of the environment resulted into banning or restricted use of most organochlorine pesticides under the Persistent Organic Pollutants Stockholmn Convention, due to their persistence and toxic effects to non- target organisms. As a result, knowledge of the environmental effects of chemicals introduced into the environment has become of great importance. The current study investigated the potency of mesophile bioremedation of 2,4-D and metribuzin herbicides in Kenya acidic and basic soils from sugar and rice belts respectively. The bio-stimulation studies were carried out using sterile, un-amended, and amended soils in mineralization experiments.

 

2,4-D and metribuzin showed faster mineralization in basic soil than acidic soil, and organic amendment considerably enhanced mineralization in acidic soil, whereas sterile soils showed negligible mineralization rates. The percentage of the total 2,4-D mineralized in basic soils increased from 1.35720.1887, 54.35330.5594, 54.49150.4242, 55.24860.6515 to 56.80110.3330 percent in 149 days, whereas as the values for acidic soils were 2.33670.1541, 22.87710.1877, 28.76030.8204, 49.25530.3328 and 63.90900.9611 percent in 121 days for sterile, unamended, and soils amended with 1000, 2500, and 5000 g/g organic compost respectively. Mineralization of metribuzin in basic soil increased from 0.98760511, 24.89880.2581, 25.32450.1755, 26.09140.3707 to 26.30600.4607 percent in 149 days, whereas values for acidic soil increased from 0.83860.1910, 2.54550.2880, 3.76440.5928, 8.42970.8520 to 10.86690.6741 in 121 days for sterile, unamended and soils amended with 1000, 2500, and 5000 g/g organic compost respectively. The differences in extent of mineralization were attributed to the presence of pesticide degrading microorganims, soil type, moisture, pH, bulky density and differences in mineral constituents.

 

The Fate of Technical Endosulfan in Lake Victoria Sediment

 

John Wasswa and B. T. Kiremire

Chemistry Department, Makerere University

P. O. Box 7062 Kampala

 

E-mail: jnwasswa@chemistry.mak.ac.ug

kiremire@chemistry.mak.ac.ug

 

Abstract

 

The fate of technical endosulfan (a and b) in Lake Victoria sediment was investigated by studying adsorption and dissipation properties of the isomers using laboratory bench scale measurements. Adsorption experiments were performed using the batch technique and the adsorption data was described by the Freundlich linear equation. Studies to determine the rate of dissipation of endosulfan from the sediment were conducted under controlled laboratory conditions. The parent compounds in the extracts were determined using a GC equipped with ECD, on a non-polar column (DB-1) and hydrogen as the carrier gas. Degradation was assumed to follow first order rate equation. Results suggest that the alpha isomer is more likely to be found in the lake water than the beta isomer since the former has a lower Kd value than the later. The half-life of dissipation of the beta isomer was estimated to be 35 days and that of the alfa isomer was estimated at 20 days.

 

 

A Preliminary Study On Pesticide Residues in Fish from Lake Victoria.

 

Christine Kyarimpa, John Wasswa and B.T. Kiremire

Chemistry Department, Makerere University

P. O. Box 7062 Kampala

 

E-mail: chriskyarimpa@avu.org

jnwasswa@chemistry.mak.ac.ug

kiremire@chemistry.mak.ac.ug

 

Abstract

 

Fish samples of three different species (Nile perch, Tilapia, and Mud fish) and of varying age, were collected from Napoleon gulf, Thurstone bay, Murchison bay and Waiya bay of the Ugandan side of Lake Victoria. The samples were extracted by a solid dispersion method and analyzed for the presence of pesticides using a Perkin Elmer Gas Chromatography equipped with a 63Ni electron capture detector after a Florisil and GPC column clean-up. Preliminary results, for which confirmatory runs are yet to be made, suggest the presence of HCH gamma, pp-DDT and Endosulfan sulphate in mature Nile perch, Tilapia and Mud fish. No residues have so far been detected in the young fish.

 

Enhancement of biodegradation of pesticides in soil

 

By

Zachary M. Getenga.

Western University College of Science of Technology

P.O. Box 190, Kakamega, Kenya.

E-mail: zgetenga@yahoo.com

Tel.: 0722-671805; 057-22658.

 

Abstract

 

Pesticide residues are usually extracted from environmental samples by exhaustive solvent extraction before quantitatively determined by analytical techniques such has thin layer chromatography (TLC), gas liquid chromatography (GLC) or high pressure liquid chromatography (HPLC). This kind of technique has always predicted low values of half-life periods for the pesticide compounds in the environment. This is because it has been found that a larger portion of the pesticide remains in environmental samples, which is not accessed by exhaustive solvent extraction. This portion referred to as non-extractable (bound) residue builds up in the environment with time, while the extactable residue, which is accessed by exhaustive solvent extraction decreases. Depending on a particular pesticide compound the extractable residue exhibits diverse behavior in the environment.

 

Most initial studies showed that the extractable residue would build up in the environment and reach a maximum and remain permanently in the environment. Later studies showed that the non-extractable residue became bio-available meaning that it could be accessed and freely became mobile in the environment. In several studies carried out by the author by use of radioisotope tracer techniques on many pesticide compounds the behavior of the non-extractable residue varied from one compound to the other. The non-extractable residue of 14C-labelled malathion in soil initially built up in soil and reached a maximum 20 days after application to soil under field conditions. Thereafter, the non-extractable residue started decreasing (Getenga et al., 2000a). In another study, where both malathion and dimethoate were studied in a greenhouse, non-extractable residue of malathion built up in the soil and reached a maximum of 45% of the initially applied pesticide dose and thereafter started decreasing. However, the non-extractable residue of dimethoate, which is also an organophosphate, built up in the soil reaching a maximum of 41.3% of the initially applied pesticide dose. Thereafter, the non-extractable residue did not decrease (Getenga et al., 2000b). In foliar dissipation studies of both 14C-labelled malathion and dimethoate, non-extractable residues of both pesticides built up in the pea plant (Pisum Sativum) reaching 4.2% and 5% for malathion and dimethoate, respectively after 16 days. For both compounds the non-extractable residue did not decrease (Getenga et al., 2000c).

In order to enhance the biodegradation of pesticides in the environment so as to reduce their persistence, various organic materials such as manure, corn meal, ammonium phosphate, rice husks, starch, composted grass clippings have been added to soil. The author has carried out such studies with different pesticide compounds in soil amended with compost made from garbage collected from urban centers. The results have been varied. Biodegradation of 14C-labelled 2,4-D and metribuzin in soil amended with compost up to the application rate of 5000ppm resulted in 58% of 2,4-D and less than 10% of metribuzin being biodegraded to 14CO2 after 120 days of incubation. Biodegradation curves for both pesticides did not exhibit lag phases (Getenga et al., 2003). Biodegradation of 14C-labelled atrazine in compost-amended soil up to the application rate of 5000ppm resulted in 60% of atrazine being biodegraded to 14CO2 after 112 days of incubation. The biodegradation curve for atrazine exhibited a lag phase that lasted for 15 days (Getenga, 2003).

From the results obtained so far compost could be a potential soil amendment capable of catalyzing the biodegradation of pesticides in soil thus enhancing the bioremediation of degraded environment.

 

 

Chemodynamics of Pure and Formulated Endosulfan and Fenitrothion in Tilapia Species, Water and Sediments, Under Laboratory Conditions.

 
By
Leonia Henry
University of Dare es Salaam, Box 35061, Dar.

Email: henry@chem.udsm.ac.tz

 

Abstract

 

Chemodynamics of pure and formulated endosulfan and fenitrothion were studied in Tilapia species (Tilapia rendalli and Tilapia zillii), both at high and low concentrations. Endosulfan was tested at 0.02, 0.002 and 0.0006 mg/L and fenitrothion at 12, 4.1 and 1.0 mg/L. The species demonstrated high capacity of absorbing the pesticides to certain maxima, after which there was a steady elimination of the pesticides. Even distribution patterns of the pesticides in tilapia were observed with statistically insignificant mean differences between organs, except for muscles, which contained minimal levels of the pesticides throughout the experiments. Bioaccumulation factors (BAFs) of up to 1938 and 73 L/kg were observed for endosulfan and fenitrothion, respectively, when T. rendalli were subjected to high dose experiments. Steady decreasing of the pesticide concentrations was observed for fenitrothion in water and sediments revealing its preferential metabolism. Interestingly, the formulated products (Thionex 35% EC and Sumithion 50% EC) exhibited relatively higher knock down effect to test organisms than the pure active ingredients.

 

 

Dissipation and Sorption of Propanil in Soils From Mahonda-Makoba Drainage Basin and Cheju Rain fed Rice Field, Zanzibar, Tanzania.

By

Aviti J. Mmochi1 and M. Kishimba2

Email:mmochi@ims.udsm.ac.tz

kishimba@chem.udsm.ac.tz

1. Institute of Marine Sciences, Institute of Marine Sciences, University of Dar Es Salaam, P.O. Box 668, Zanzibar, Tanzania.

2. Chemistry Department, University of Dar Es Salaam, P.O. Box 35061 Dar Es Salaam, Tanzania.

 

Abstract

 

Propanil is a photosynthesis inhibiting pesticide used in Zanzibar rice farms as a herbicide. Propanil has been used continuously in Zanzibar from 1994 as Satunil whose active ingredients are propanil 20% and thiobencarb. There have been reports of fish mortalities or disappearances that seem to coincide with the time of application of the chemicals in the two areas. Propanil residues have been found in Cheju at reasonably high concentrations to warrant further investigations. In this study the properties of the pesticide in soils from the two areas are investigated.

 

The results indicate presence of the pesticide in the soil long after the season of application despite its short half-life of 11 hrs in water and a few days in soil. The Cheju soil seems to have a high binding effect due to low Freundlishs constants Kf and n compared to soils from Mchanga and Cheju. The half-life time for the laboratory experiment ranged from the lowest of 13.9 in Mchanga to the lowest in Makoba contradicting both the soil organic matter coefficient and the amount of clay mineral in the soil.

 

Despite the high dissipation rate of propanil, it is capable of contaminating the ground water and the sea where the sorption capability of the soil is as poor as is the case with Cheju. This explains the presence of propanil both in well water, stagnant rainy waters and seawater in Cheju and Mapopwe but not Mahonda and Makoba The study also suggests that a factor other than soil organic matter is responsible for the dissipation rates.

 


PESTICIDE RESIDUES IN WATER, SEDIMENT AND SOIL FROM THE HYDROMORPHIC RICE VALLEYS OF PEMBA ISLAND

Mwevura, H.

Chemistry Department, University of Dar es Salaam, P.O. BOX 35061,

Dar es Salaam, Tanzania.

e-mail: mwevura@chem.udsm.ac.tz

 

Abstract

 

Concentrations of organochlorine and organophosphorous pesticides were determined in

surface and ground waters, sediments and soils from six hydromorphic rice valleys of Pemba Island, using GC-ECD/NPD. Among the analysed pesticides, DDTs, dieldrin, HCHs , fenitrothion and diazinon were detected in which p,p DDT and its metabolites were the dominating residues. Total DDT concentrations ranged from <0.05 0.26 mg/l in ground water, 0.17 1.31 mg/l in surface water, 1.89 8.95 mg/kg dry weight in sediments and 1.21 11.33 mg/kg dry weight in soil. Total HCHs were measured from < 0.01mg/l up to 0.18 and 0.86 mg/l in ground and surface waters respectively, whereas in sediment and soil the residues were up to 2.8 and 2.5 mg/kg dry weight, respectively. Levels of dieldrin were up to 0.42 mg/l in waters, 5.06 mg/kg dry weight in sediment and 4.18 mg/kg dry weight in soil. Detection of organophosphorous pesticides (Fenitrothion and diazinon) was associated with recent application and the mean ratios of fresh DDT/ total DDT in six valleys ranged from zero to 0.28 indicating no fresh application of DDT. Almost all site showed a general trend of pesticide concentrations of Soil> Sediments> Surface water> ground water and Tibirinzi rice valley was found to be the most contaminated amoung the surveyed valleys. The results showed that, current contamination level does not pose acute threat but it indicates possibility of ground water pollution.

 

 

Glyphosate! The quintessential panacea or a ticking time bomb?

 

Kengara F.O. a, Getenga Z.M. a, & Wandiga S.O.b

a: Department of Chemistry, Maseno University

b: Department of Chemistry, University of Nairobi

Email: fkengara@yahoo.com

zgetenga@yahoo.com

sowandiga@iconnect.co.ke

 

Abstract

 

The research was carried out on soil from Chemelil Sugar Company, which is found in the Sugar Belt region, a catchment area of Lake Victoria. Glyphosate, which is marketed as Round Up, is widely used in the sugar belt to control weeds. Environmental fate studies on this herbicide have never been carried out in this country. It was therefore necessary to study the fate of glyphosate in soil and thus determine whether it posed any environmental danger.

 

Various concentrations of compost were added to soil samples to study if it enhanced the dissipation of glyphosate from soil thus reducing its persistence. The sorption studies were to determine whether the herbicide is capable of being transported through the soil into underground water and into the rivers draining through the region thence to Lake Victoria. The economic importance of Lake Victoria to the East African region and to other nations relying on the River Nile can never be overemphasized. It is therefore necessary to monitor the pollution load into the lake and carry out remedial action.

 

Laboratory studies on pesticide-free soil were carried out using radiolabelled glyphosate. The glyphosate was phosphono-methyl 14C-labelled. In the incubation experiments compost did not have a great effect on the dissipation of glyphosate.

 

There was 10.9800.0092%, 9.7690.0063%, 9.9860.0188% and 10.8190.0054% mineralization of the initially applied label in the untreated, 1000ppm, 2500ppm and 5000ppm compost treated samples respectively after 50 days of incubation. The 4.9630.0051% mineralization witnessed in the autoclaved set was due to ineffective sterilization. There was no lag phase in the mineralization of glyphosate. The extractable residues were minimal and ranged between 0.059.74E-05 and 0.350.0001% of the initially applied label. The bound residues were 77.630.004%, 82.7760.096%, 92.450.137%, 88.740.061%, 88.740.061% and 82.050.190% for the autoclaved, untreated, 1000ppm, 2500ppm and 5000ppm compost treated samples respectively.

 

The adsorption of glyphosate was constant irrespective of the concentration of the herbicide in solution. On average 95.70.4% of the initial herbicide was adsorbed by the soil. The adsorption isotherm was linear with Kf = 77.43 and n = 1.04. Desorption was negligible and averaged 1.10.2% of the initial label.

 

In the photolysis experiments, UV irradiation increased the dissipation of glyphosate in soil remarkably. First order kinetics was exhibited in the dissipation of glyphosate. 38.30.517% and 48.50.740% of the initially applied amount remained after 42 days in the exposed and covered samples respectively.

 

A small degree of mineralization and volatilization was noted in the photolysis of glyphosate in soil. 0.00740.00041% and 0.01240.00023% of the initially applied label was mineralized after 42 days in the covered and exposed samples respectively. 0.00470.00041% and 0.00667.9E-05% of the initial glyphosate label was evolved as volatile fraction in the covered and exposed samples respectively after 42 days. Thus, higher amounts of 14CO2 and volatile fraction were evolved in the exposed sample. In the photolysis of the pesticide only, the concentration of the covered glyphosate did not decrease after 8 weeks. The exposed sample, however, decreased to 84.490.37% of the initial amount.

 

 

 


Organochlorine residues in Nyando Basin of Lake Victoria

 

Kengara O.F.1, Getenga Z.M. 1 and Wandiga S.O. 2

1.   Department of Chemistry, Maseno University, P.O. Box 333, Maseno, Kenya.

2.   Department of Chemistry, College of Biological and Physical Sciences, University of Nairobi, P.O. Box 30197, Nairobi, Kenya.

Email: fkengara@yahoo.com

zgetenga@yahoo.com

sowandiga@iconnect.co.ke

 

Abstract

 

There is increasing concern over the state of Lake Victoria and a lot of research activities are taking place within the Lake and its environs. However there is very limited information on the state of pesticide pollution of the Lake. This study was meant to bridge this gap.

 

The research was carried out in the sugar belt region, a Lake Victoria catchment area, where pesticides are extensively used. Soil samples were collected from Chemelili Sugar Factory, which was selected as a representative of the region. Samples in which pesticides had been in the soil for various periods of time were collected. Water samples `were collected at various points from rivers draining through the region into the lake.

 

The samples were analyzed for the presence of pesticides using a Varian Chrompack-3800 GC. Electron Capture Detector (ECD) was used to analyze for organochlorines. Organochlorines were detected in the soil and water samples analyzed. The organochlorines detected included the isomers of BHC, heptachlor and its epoxide, aldrin, endrin, dieldrin, endosulfan and methoxychlor.

 

LIST OF PARTICIPANTS

 

NAME

ADDRESS

EMAIL $ TEL CONTACTS

1.    S. O. Wandiga

University of Nairobi,

Department of Chemistry,

Box 30197,

Nairobi, Kenya.

sowandiga@iconnect.co.ke

 

254-44446140

2.     Michael Kishimba

University of Dar-es Salaam,

Box 35061,

DSM-Tanzania.

kishimba@chem.udsm.ac.tz

 

 

3.     Bernard T. Kiremire

Makerere University,

Box 7062,

Kampala-Uganda.

kiremire@chemistry.mak.ac.ug

 

4.     Negussie Mergersa

University of Addis Ababa,

Chemistry Department,

Box 1176,

Addis Ababa, Ethiopia.

nmergersa@chemistry.aau.edu.et

5.     Haji Mwevura

University of Dar-es Salaam,

Chemistry Department,

Box 35061,

DSM-Tanzania.

mwevura@chem.udsm.ac.tz

 

 

 

6.     Juma M. Makopa

University of Nairobi,

Department of Chemistry,

Box 30197,

Nairobi, Kenya.

jmakopa@uonbi.ac.ke

 

7.     Z. M. Getenga

Western University College of

Science of Technology,

Box 190,

Kakamega, Kenya.

 

zgetenga@yahoo.com

 

 

8.     John Wasswa

Makerere University,

Box 7062,

Kampala-Uganda.

jnwasswa@chemistry.mak.ac.ug

 

9. Madadi O. Vincent

University of Nairobi,

Department of Chemistry,

Box 30197,

Nairobi, Kenya

madadivin2002@yahoo.co.

 

10. Fredrich O. Kengara

Maseno University,

Department of Chemistry,

Box 333,

Maseno, Kenya.

fkengara@yahoo.com

 

Tel: 254-0722262159

 

11. KyarimpaChristin

Makerere University,

Box 7062,

Kampala-Uganda.

christinkyarimpa@avu.org

 

 

12. Leonia Henry

University of Dar-eslaam,

Chemistry Department,

Box 35061,

DSM-Tanzania.

henry@chem.udsm.ac.tz

 

13. Geofrey Malisa

University of Dar-es Salaam,

Chemistry Department,

Box 35061,

DSM-Tanzania.

malisa@chem.udsm.ac.tz

 

14. Avit J. Mmochi

University of Dar-es Salaam,

Institute of Marine Sciences,

Box 668,

Zanzibar-Tanzania.

mmochi@ims.udsm.ac.tz

Tel: 255-242230741

 

15. Orata Francis

University of Nairobi,

Department of Chemistry,

Box 30197,

Nairobi, Kenya

fraora@yahoo.com

 

16. Philip K. Maritim

Moi University,

School of Environmental Studies,

Box 3900,

Eldoret, Kenya.

pkmaritim@yahoo.com

 

 

17. Tarekegn Berhanu

University of Addis Ababa,

Chemistry Department,

Box 1176,

Addis Ababa, Ethiopia.

tarekegnbr@yahoo.com

 

 

18. Lutufyo Mwamtobe

University of Dar-es Salaam,

Chemistry Department,

Box 35061,

DSM-Tanzania.

mwamtobe@chem.udsm.ac.tz

 

 

19. Ahmed Hussen

University of Addis Ababa,

Chemistry Department,

Box 1176,

Addis Ababa, Ethiopia.

ahdekebo@yahoo.com

 

 

20. Andrew A. Andayi

Maseno University,

Department of Chemistry,

Box 333,

Maseno, Kenya.

andrewandayi@yahoo.com

 

 

21. Joseph Ng'ang'a

University of Nairobi,

Department of Chemistry,

Box 30197,

Nairobi, Kenya

 

22. V. Muinde

University of Nairobi,

Department of Chemistry,

Box 30197,

Nairobi, Kenya

vmuinde@uonbi.ac.ke

 

 

23. Matobola J. Mihale

University of Dar-es Salaam,

Chemistry Department,

Box 35061,

DSM-Tanzania.

mihale@chemistry.udsm.ac.tz

 

 

24. F. Seme

Government Chem Lab

Box 164,

Dar-eslaam, Tanzania

gcla@gclago.tz

Tel: 255-22-2113383/4