Vincent O. Madadi

Occurrence, abundance and distribution of benthic macroinvertebrates in the Nyando River catchment, Kenya

A baseline study was conducted of the occurrence of macroinvertebrates at 26 sites in the Nyando River catchment in 2005–2006. A total of 13 orders and 16 families of Arthropoda, Mollusca, Platyhelminthes and Annelida were collected, with the order Ephemeroptera being most abundant in the up- and mid-stream reaches, followed by Hemiptera and Plecoptera respectively. The downstream sections of the river were dominated by Hirudinea and tubificids, as the water quality deteriorated mainly due to local land use, raw sewage effluent discharge and annual floods. Insects and annelids were the main invertebrates found and the extent of pollution increased from mid-section (Site 15) downwards as the river flowed into the Winam Gulf. Stringent management measures are required to safeguard the environment and ecosystems of Lake Victoria.

Water Quality Issues in Eastern Africa

There is only about one percent of water available to meet human needs. Further analysis of the available water shows that the blue water locked up in lakes and reservoirs and the green water (rainfall water) have become increasingly polluted with human, industrial and agricultural wastes, and cosmetic chemicals. Scientific challenges exist in determining the quantities of such wastes and their breakdown products, effects on life and environment, and how best to control their distribution in the environment. This chapter describes some of the challenges existing in East Africa. Climate change has added to the urgency of need for water conservation. Several challenges face water systems such as Lake Victoria. Some of the recent challenges are human activities contributing to chemical pollution, such as washing clothes with phosphate detergents, car wash, and agricultural sediments. One of the major sources of water pollution in East Africa is human waste. The effluents from untreated municipal sewers pose great danger to Lake Victoria sustainable ecological conservation. The presence of pesticides at the top of the food chain is reported in some studies and may be of critical concern. Study establishes high levels of phosphorus in the soils around Lake Victoria especially at the beaches, indicating that the human settlement and related anthropogenic activities strongly contribute to the phosphorus load into the lake waters.

OrganochlorinePesticides Residue Levels in Airand Soilfrom Nairobiand Mount Kenyaregions, Kenya

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), αendosulfan, βendosulfan and Endosulfansulfate. The samples were collected seasonally between the monthsof July 2012 and April 2013. The residue levels of organochlorine pesticides in air samples during month of October ranged between0.027±0.004 to5.735±0.575 ng/M 3 , while during the Month of February the concentration ranged between 0.013±0.00 to 9.375±1.65 ng/M 3 and the levels during the month of April ranged between 0.013±0.00 to 11.508±0.26ng/M 3 . Organochlorine pesticide detected in soil during month of October ranged between BDL to 131.206 ± 14.41ng/Kg, while during the Month of February the concentration ranged between 0.418± 0.01to 38.361 ±5.39 ng/Kg and the levels during the month of April ranged between 0.406± 0.00to 26.877± 8.89 ng/Kg. The residue levels of the analysedPOPs in air and soil were generally high at the Dandora and Industrial area sites. This indicates that industrial activities such as Tetra-Pac, general plastics, Phillips industries waste and stock piles are the main sources of the new POPs in Nairobi. The high concentration level poses a health risk to residents of Dandora and Industrial area workers.