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Publications


2017

O, OD, O WANDIGAS, A A’oD.  2017.  Synergistic Effects of Titanium (IV) Oxide Modified Clay for Disinfection and Purification of Water. European International Journal of Science and Technology . 6(5):7-32.
K, OE, V.O M, A A’oD, A O.  2017.  Assessment of the Level of Organochlorine Pesticides Contamination in Kales, Water and Soil from Naivasha, Kenya. . International Journal of Scientific Research in Science, Engineering and Technology . 3(5):205-213.
JK, A, O WANDIGAS, A A’oD, O MV, EM O.  2017.  Organochlorine Pesticides Residue Levels in Air and Soil from Nairobi and Mount Kenya regions, Kenya. Journal of Applied Chemistry. 10(7):5-11.
J, KC, O OFD, DA A.  2017.  Assessment of Domestic Water Quality of Dams in Chepalungu Sub-county, Bomet County, Kenya.. The International Journal of Science & Technology. 5(6):144-130.
A, A’oD, J.O O, M H.  2017.  The Effect of Septic Tanks Sewage Disposal System Distances On Borehole Water Quality in Ongata Rongai, Kajiado County, Kenya:. The Effect of Septic Tanks Sewage Disposal System Distances On Borehole Water Quality in Ongata Rongai, Kajiado County, Kenya. 6(3):1-10.
Mwaniki O K, A A’oD, O OJ, G KJ.  2017.  Investigating the Effects of Formulation, and Geographical Location on Degradation of Carbendazim in French Beans, Kenya. The International Journal of Science & Technology . 5(2):44-51.

2016

E, TJP, O WANDIGAS, A A’oD.  2016.  Methane and heavy metals Levels from leachates at Dandora dumpsite, Nairobi County, Kenya. IOSR Journal of Applied Chemistry. 9(9):39-46.janniffer_publication.pdf
EM, O, O WANDIGAS, DA A, O MV, W MJ.  2016.  Organochlorine Pesticides Residues in Water and Sediment from Rusinga Island, Lake Victoria, Kenya. IOSR Journal of Applied Chemistry. 9(9):56-63.osoro_publication.pdf

2015

D.A, A’o, O WANDIGAS, O JI, den J VBP, B NB, O MV, A WG, P N-K, H K.  2015.  Occurrence, abundance and distribution of benthic macroinvertebrates in the Nyando River catchment, Kenya. African Journal of Aquatic Science. 40(4):373–392.benthic_macroinvertevertebrates_in_nyando_river.pdf
D.A, A’o, O WANDIGAS, O JI, den J VBP, B NB.  2015.  Organochlorine pesticide residue levels in soil from the Nyando River Catchment, Kenya . Africa Journal of Physical Sciences. 2(1):18-32.

2014

2009

Abong'o, D, Wandiga SO.  2009.  Occurrence, distribution and environmental impact of organochlorine pesticide resedues in the Lake Victoria catchment: a case study of River Nyando drainage basin. AbstractFull text link

The study was to investigate the impacts on the ecosystem health in relation to levels and distribution of organochlorine pesticides that have either been banned or restricted for use in Kenya. The pesticides targeted were DDT, lindane, aldrin, dieldrin, heptachlor, endrin, endosuphan, and methoxychlor. Prior to their ban or restriction in use, they had found wide applications in public health and agriculture for control of disease vectors and crop pests respectively.

A study was conducted in which 880 samples of soil, water, sediments, aquatic weeds and benthic macroinvertebrates were collected from 26 locations representative of the River Nyando drainage basin catchment area of 3450 km2 and a total length of 170 km of the Lake Victoria Catchment over a period of two years. Soils from six farms were sampled in areas where maize, tea, sugar cane, col fee, rice and vegetables have been grown over the years. The objective was to investigate the impacts on the ecosystem health in relation to levels and distribution of oraganochlorine pesticides that have either been banned or are restricted for use in Kenya. The pesticides targeted were DDT, lindane, aldrin, dieldrin, heptachlor, endrin, endosulfan and methoxychlor. Pior to their ban or restriction in use, they had found wide applications in public health and agriculture for control of disease vectors and crop pests respectively. Analysis of 48 soil samples revealed presence of all the targeted pesticides. Mean concentrations (pg/kg) recorded decreased in the order methoxychlor (138.97±1.517 pg/kg), total (X) endosulfan (30.267±2.098pg/kg), £DDT (17.513± 1.689 pg/kg), dieldrin (14.073±0.440 pg/kg), endrin (10.155±0.860 pg/kg), lindane (8.985±1.318 pg/kg) and ^Heptachlor (0.681±0.021 pg/kg), respectively. The distribution showed that dieldrin was in use in vegetable farms in Kedowa area, tea farms in Nandi District and in Ahero rice paddies; while p-endosulfan was commonly used on tea farms in Nandi. Water analysis from the 26 sampling sites showed the highest mean concentrations were detected for methoxychlor (8.817±0.020 pg/L), ^endosulfan (1.648± 0.04 pg/L), dieldrin (1.1561± 0.042 pg/L), endrin (0.281± 0.003 pg/L), £DDT (0.242±0.009 pg/L), £heptachlor (0.148±0.01 lpg/L) and lindane (0.144±0.006pg/L) respectively. The detected levels in sediments were considerably higher than those found in water in the order, methoxychlor (92.893±3.039 pg/kg ), lindane (33.917±2.360 pg/kg), aldrin (26.676±0.981 pg/kg ), dieldrin (23.62±4.810 pg/kg) and P-endosulfan, (10.502±0.800 pg/kg), respectively. The analysis of aquatic weeds recorded methoxychlor (39.641±3.045 pg/kg) as the highest residue concentrations, followed by aldrin (15.519±3.756 pg/kg). These higher levels may be as a result of continued use of the pesticide in the drainage basin. The levels of pesticides were higher in sediment, weeds and soil than in water. The pooled results show that the targeted pesticides are still in use in the basin and could be impacting negatively on the ecosystem health of the area. A study of the composition of the benthic macroinvertebrates showed presence of four invertebrate phyla in River Nyando. These were Arthropoda, Mollusca, Plathelminthes and Annelida. A diversity of 16 families and eleven orders was recorded, with the order Ephemeroptera being abundant upstream followed by Hemiptera, Plecoptera and Trichoptera respectively. The downstream sections mainly the rice farming areas were dominated by Hirudinae (leaches) and Oligochaeta, suggesting that they are less sensitive to environmental pollution. Using Multivariate analytical techniques, Redundancy Analysis and Canonical Correspondence Analysis, correlation statistics showed that the occurrence of organochlorine pesticides strongly affects the distribution of the benthic macro invertebrates at all the sampling locations within the drainage basin. The high concentrations of pesticide residues were detected mostly in the soils and water from rice farms, these magnitudes were followed by those from tea farms. This implies that the rice farmers use most pesticides followed by tea farmers and there the proximity of the rice paddies to Lake Victoria could pose a greater impact to ecosystem health in the entire catchment than the upstream tea, sugar cane, maize and coffee farms owing to pesticide discharge; and this call for stringent management measures to be put in place to safeguard the environment.

2004

Kasima, E, Yusuf A, Kariuki K, Abong'o D.  2004.  Evaluation of efficiency of Kipevu wastewater treatment plant in Mombasa County, Kenya. Scholar.
Aucha, JK, Wandiga SO, Abong’o DA, Madadi VO, Osoro EM.  2004.  OrganochlorinePesticides Residue Levels in Airand Soilfrom Nairobiand Mount Kenyaregions, Kenya. Researchgate. AbstractFull text link

Thestudy investigates the organochlorine pesticides residue level in air and soilat
sites in Nairobi and Mount Kenya regions, Kenya. Air and soil samples from four sites were
collected and analysed for selected organochlorine pesticides (OCP) using gas
chromatography equipped with electron capture detector and confirmed using GC/MS. The
targeted pesticides were α-HCH, β-HCH, γ-HCH (lindane), α-endosulfan, βendosulfan and
Endosulfansulfate.

Thabano, JRE, bong’o DA, Sawula GM.  2004.  Determination of nitrate by suppressed ion chromatography after copperised-cadmium column reduction. Journal of Chromatography A. 1045(1):153-159. AbstractFull text link

The nitrate-selective copperised-cadmium (Cu-Cd) reduction reaction coupled directly to the highly sensitive nitrite ion chromatographic detection, produced a more precise method for determination of nitrate than any one of the two conventional methods. A borate buffer solution used in the reduction reaction, in place of the conventional ammonium–EDTA buffer solution, eliminated interferences from co-eluting ions in the subsequent ion chromatographic detection of nitrite. Optimised experimental conditions included using a packed-bed Cu-Cd reductor column length of 12.5 cm, a solution flow rate of 3.0 ml/min, and using 10.0 ml of borate buffer solution for each 20.0 ml of nitrate-containing solution. Precision was high for results obtained within a greatly extended linear dynamic range of 0.006–1.20 mg/l NO3−, with a much lower limit of detection of 0.40 μg/l NO3−. Cu-Cd reductor column efficiency was 98.20 ± 6.03%. Validation of the method was undertaken using certified reference materials. The method was successfully applied to analysis of dam water, river water and storm water samples, producing more precise results than either the conventional colorimetric method or the conventional ion chromatographic method.

Thabano, JRE, D.Abongo, Sawula GM.  2004.  determination of nitrates using suppressed ion chromatography after copperised cadmium column reduction . Journal of chromatography A. 1045:153-159.thabano_publication.pdf

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