Nature & Wildlife

IMPACTS OF PESTICIDES ON HUMAN HEALTH AND ENVIRONMENT IN THE RIVER NYANDO CATCHMENT, KENYA

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River relies on rain fed agriculture. Important crops grown include cereals, cash crops fruits and vegetables. Farming is one of the contributors’ of pollution to Lake Victoria. Organophosphates and other banned organochlorine pesticides such as
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   IMPACTS OF PESTICIDES ON HUMAN HEALTH AND ENVIRONMENT IN THE RIVER NYANDO CATCHMENT, KENYA DEBORAH ATIENO ABONG’O 1 , SHEM OYOO WANDIGA 2 , ISAAC OGANGU JUMBA 3  VINCENT ODONGO   MADADI 4  & HENRIK   KYLIN 5   1,2,3,4 Department of Chemistry, School of Physical Science, College of Biological and Physical Sciences University of Nairobi, Nairobi, Kenya 5 Department of Water and Environmental Studies, Linköping University, Linköping, Sweden   ABSTRACT   River relies on rain fed agriculture. Important crops grown include cereals, cash crops fruits and vegetables. Farming is one of the contributors’ of pollution to Lake Victoria. Organophosphates and other banned organochlorine pesticides such as lindane, aldrin and dieldrin were used by farmers. The pesticides transport was by storm water run-off and air drift into the lake. Environmental risk assessment background information was collected through questionnaire and interviews of farmers to determine knowledge and safe use of pesticides. Fourteen pesticides were identified as commonly used of which four are toxic to bees and five to birds. The farmers identified declines in the number of pollinating insects, the disappearance of Red-billed Oxpecker (  Buphagus erythrorthynchus)  and wild bird’s fatalities. The general knowledge among farmers about chemicals risks, safety, and chronic illnesses was low. Activities that increases environmental awareness and safety of pesticides should be initiated by the agrochemical firms and government KEYWORDS:   Environment, Farming, Lake Victoria, Pesticides INTRODUCTION In many African countries agriculture is considered to be the key to economic development. Agro-intensification has led to negative impact on the surrounding environment in many parts of the world (Wilson and Tisdell, 2001). The challenge for future food production in Africa is therefore to intensify the agricultural production without decreasing the capacity of the environment to supply the population with other ecosystem services. Agriculture has been a mainstay of the Kenyan economy. It is the basis for food security, for economic growth, employment creation and foreign exchange generation. Most of the agricultural production in Kenya comprises mixed farming, i.e., crop and livestock farming. Agriculture accounts for 60% of Kenya’s foreign exchange earnings and provides raw materials for the industries (NIP, 2006). Hence there is tendency towards the use of chemicals especially fertilizers, veterinary chemicals and pesticides. Farming is more intensive in the tropical savannah zones than in the arid and semi-arid areas where cattle, sheep and goat rearing predominate. Safe storage and disposal of pesticides and fertilizers remain a challenge in the agricultural areas. Rapid expansion of the agriculture due to increasing population has resulted in increased demand for agro-chemicals in Kenya and Pesticides have become an integral part of plant, livestock and public health protection (NES, 2006). However, increasing evidence suggests that pesticides have intrinsic public health and environmental risks during their production, import, use, storage and disposal (Stadlinger et al. 2013). Many pesticides used in all societies have been associated with toxicity to human (Jacobs and Dinham, 2001) and others are suspected to be carcinogenic, mutagenic, and endocrine disruptors (Colborn et al., 2004). Current registration practices are put in place to, as far as possible, ensure BEST: International Journal of Humanities, Arts, Medicine and Sciences (BEST: IJHAMS) ISSN(E): 2348-0521 Vol. 2, Issue 3, Mar 2014, 1-14 © BEST Journals    2   Deborah Atieno Abong’o, Shem Oyoo Wandiga, Isaac Ogangu Jumba, Vincent Odongo   Madadi & Henrik   Kylin that proper use of pesticides minimizes risks to environmental and human health, but controls and enforcement of regulations are less than strict in the River Nyando basin, reflecting a situation common to many developing countries (Stadlinger et al. 2013). The pesticides when used properly may pose low risk to the environment and human health as long as strict controls are put in place. Point sources arising from stored obsolete pesticides have been identified as locally very important threats to the African environment (Elfvendahl et al., 2004; NES, 2006), while the consequences of diffuse use in agriculture has been less studied. Recently, work by Sereda et al., (2009) indicated that pyrethroids found in human breast milk may come from agricultural use. Bouwman and Kylin (2009) pointed out the need to include agricultural and other uses of pesticides when evaluating risks to infants from pesticides used for vector control. The reported rapid degradation of some pesticides in Kenyan soil not withstanding (Wandiga et al., 1996) the potential for bioaccumulation and bio-concentration of these pesticides pose serious ecological and health concerns for the environment. All types of land use in the lake Victoria catchment in one way or another affects the quality of its water and that of the tributaries (Shephard et al., 2000). Pesticides leaching or draining from agricultural land may pollute surface and ground water. The Nyando and Kagera Rivers carry higher sediments, pesticides and nutrients loads into the lake than other rivers (Calamari et al.; 1995). This has created a significant pollution problem that threatens the use of the lake’s resources for national development (Odada et al., 2009). The pollution problem in Kenya’s part of Lake Victoria was noted by the committee for Inland Fisheries of Africa (CIFA) sub-committee meeting held in Mwanza (Tanzania) in 1989 since Kenya has the least catchment area with 6 major rivers carrying pollutants into the lake. The relatively secluded Kenya’s part of Lake Victoria, Winam Gulf is the most polluted part of the lake (Calamari et al.; 1995). Winam Gulf catchment) comprises the North and Southern lakeshores in Kenya, including the River Nyando and Sondu-Miriu basins with a total area of 11,994 km 2 . Some incidences of pesticide poisoning of fish was highlighted by the press in May 1999, the fish was purported to be harvested from the lake by use of endosulfan, an organochlorine insecticide. This resulted in a ban by the European Union (EU) on all fish import from Lake Victoria (LVEMP/MoALD& M, 1999). The EU demanded that the three East Africa countries submit a list of all chemicals sold in the region, their toxicity to humans and their persistence in fish and water before any negotiations begun (LVEMP/MoALD& M, 1999). Commercial fishing activity around the lake and subsequently the economies of the three riparian countries were greatly affected as a result. Total loss of income due to the ban was estimated to be more than US$ 300 million (LVEMP, 2003). Although there are individual reports on pesticide concentration in fish (Henry and Kishimba; 2006), water (Getenga et al., 2004), soil and sediments (Abong’o, 2009) from parts of the lake, there is no comprehensive analysis of pesticides use, distribution and fate in Lake Victoria or any of its drainage systems. Lack of basic information on pesticides use, overfishing, water hyacinth invasion and sewer pollution have resulted in the decline of fish in the lake (LVEMP, 2003). However the absence of surveillance programs for pesticide residue levels in the agricultural and fisheries products from the Lake Victoria basin has wider policy and market implications. Absence of such programmes may be detrimental to the fish export from the East Africa states due to increasingly stringent regulation in the importing countries on residue limits in imported fisheries and agricultural/horticultural products. Lake Victoria fishing earns Kenya between KSh 4 billion and KSh. 6 billion (USD 85 million) annually from fish exports revenue (LVEMP, 2003), that might be lost if pollution from agrochemicals is allowed to continue.  Impacts of Pesticides on Human Health and Environment in the River Nyando Catchment, Kenya 3   The River Nyando has been identified as the most polluted drainage basin in the Kenyan side of the lake (Shepherd et al., 2000). The drainage system traverses formerly three districts (Kericho, Nandi, and Nyando), which are major agricultural and industrial zones in Western Kenya. It serves as a recipient for effluents from tea, coffee, lime and sugar factories. Farming is intense and a wide range of pesticides are used in the drainage basin. In ddition, it has the highest slope and rate of sediment transport of all the rivers draining into Lake Victoria. Arguably, poor land-use management practices (e.g., cultivating on slopes adjacent to rivers and on river banks, draining of wetlands and clearance of forest cover to give additional arable land) and intensive use of agrochemicals have resulted in a high flow of nutrients and sediments that have negative impacts on River Nyando and Lake Victoria ecosystems (Peters and Meyback, 2000). Although some studies regarding levels of pesticides in fish, water, soil and sediments have been done in Kenya, surveys of risks to farmers while using pesticides are few (Kariuki, 2008). Because of the CIFA’s concerns in 1989, the imposition of a fish import ban by the EU in 1999 and based on evidence from data available from studies conducted within the lake basin, it is important to focus on the pollution status of the Winam Gulf catchment with special focus on the River Nyando drainage basin. Studying River Nyando is important for restoration and management of the lake as part of a long-term strategy to conserve the ecosystem function in the lake basin. If a well-targeted comprehensive analysis of data on pesticide use, distribution and fate is done for one drainage system, the results can form the basis for the study of the other waterways and of the lake itself. This study was performed to identify agrochemicals used in different areas along the River Nyando drainage basin in both the large and small-scale agriculture through participatory rural appraisal (PRA) methods (Bernard, 1994). This was in assessing the effects of agrochemicals on environment and human health in the basin. Fourteen selected areas were visited in February, May, September and December 2005 and in similar periods in 2006 mainly to capture the effects of different seasons and farming activities on the agrochemical usage.   MATERIAL AND METHODS The Study Area The Nyando drainage, has a catchments area of 3450 km 2 , a total length of 170 km and lies between 0˚ 25’S to 0˚10’N and 34˚ 50’W to 35˚50’E. The climate is sub-humid with a mean annual temperature of 23 ˚C and the mean annual rainfall of 1360 mm that varies from 1000 mm near Lake Victoria to over 1600 mm in the highlands (NES, 2002). The annual rainfall has a bi-model pattern with peaks during the long rains (April-May) and short rains (October-December). The rainfall is controlled by north and southward movement of the Inter-Tropical Convergence Zone (ITCZ) during the dry seasons (January-March). The River Nyando Drainage Basin The River Nyando (Figure 1) has two main tributaries, small Nyando (Kericho sub-catchment) and Ainamotua (Nandi sub-catchment). Awach-Kano, a smaller river flows into the main River Nyando 15km downstream of the Nyando-Ainamotua confluence. The Nyando basin drains major agricultural and industrial zones of Western Kenya. The average annual and monthly run-off flows are 18.0 m 3 s -1  and 18.3 m 3 s -1 , respectively (Calamari et al.; 1995). Compared to all other rivers emptying into Lake Victoria, Nyando has the highest average sediment transport capacity index (0.30) and average slope (5%) (LVEMP, 2003).  4   Deborah Atieno Abong’o, Shem Oyoo Wandiga, Isaac Ogangu Jumba, Vincent Odongo   Madadi & Henrik   Kylin Figure 1: Map of River Nyando Basin Showing the Sampling Sites Population and Land Use The population of Nyando basin is about 746,000, an average population density of 214 persons km -2 , and a population growth of about 3.2 % yr -1  (Kenya CBS, 2009). High livestock densities are common throughout the basin. The forests are being cleared for charcoal burning and to increase arable land; wetlands are also drained to increase arable land. Small-scale subsistence maize, sorghum and rice farming characterize the lower part of the watershed and the lake plains. At higher altitudes, there are large and small-scale sugar plantations, coffee and tea estates and relatively large-scale maize and horticulture (Abong’o, 2009). The nature of the soils (alluvial) together with the multitudes of rivulets and low-lying lands that characterizes the area brings about water stagnation. Flooding is therefore a common occurrence and the area suffers from periodic inundation, particularly after heavy rains in the adjacent escarpments and hills. There is a widespread land degradation throughout the River Nyando basin that currently affects an estimated 1444-1932 km 2  (39.5-52.9%) of the area (Shepherd et.al, 2000; Odada et.al. 2009). Methodology To gain information on the benefits from pesticides and other agro-chemicals used and their perceived negative effects on the agro-ecosystem and human health, questionnaire with both open and closed end questions, field observation checklist and measurements of areas of some farms were used. The farmers whose farms are adjacent to river banks ( ≤  10 m riparian zone) within some selected urban centres and use agrochemicals on their farms or livestock constituted the target population, with 80% of the total population engaged in small-scale intensive farming and an average of farm size of 3.5 hectares per household (Kenya CBS, 2000). The sampling size was calculated using the formula for determining sample size in social science research (Mugenda and Mugenda, 1999). Random sampling was used to select sampling areas from which 64 people from each of the three former districts were interviewed. Purposive sampling was used to select key informants who included chiefs, agricultural officers and scientists from Kenya Agricultural Research Institute (KARI) and Lake Victoria Environmental Management Project (LVEMP) and pesticide retailers in the catchment. Data on existing agrochemicals safe use, handling practices, hazards and challenges involved in their use was collected using Participatory Rural Appraisal (PRA) techniques which included interviews with key informants and focus group discussion (Bernard, 1994 ).  Unstructured questions were used as interview guides to ensure that data collected met the objectives of the study. A total of 150 farmers were interviewed in the whole catchments area (Table 1). The questionnaires provided the information on, sizes of farms, types of farming and the crops grown, number and types of livestock, the planting seasons, types and quantities of chemicals used, major pests problems, farmers’ knowledge and attitude towards agrochemicals use,  Impacts of Pesticides on Human Health and Environment in the River Nyando Catchment, Kenya 5   their perception on environmental and health problems connected to use of pesticides or other chemicals. It was difficult to get an understanding of the quantities of pesticides used and the sizes of farms through questionnaires, therefore quantitative measurements of sizes of twelve farms were taken. Table 1: Description of Sampling Sites Site Local Name GIS Position Altitude (m) Number of Farmers Interviewed <10m Riparian Zone Subsistence Agriculture Forest Cover HS ≤  1km Upstream Livestock Rearing Sugar-Cane Coffee Tea Rice Perennial Floods 1 Kedowa bridge E035.54474º S00.23427° 7515±2.78 19 √   √   √  - √  - - - - - 4 Masaita at Londiani Township E035.58415ºS00.16274º 7507±3.89 15 √   √   √  - √  - - - - √   5 Masaita at Lambel farm E035.53546ºS00.19706º 6740±3.98 3 √   √  - - √  - - - - - 7 Kimoson E035.46373ºS00.20716º 6308±7.09 5 √   √  - - √  - - - - - 8 Nyando at Kipkelion E035.46185ºS00.20679º 6307±8.45 8 √   √  - √   √  - - - - - 13 Homalime E035.29911ºS00.18453º 4344±3.67 12 - √  - - √  - - - - 16 Nyando at Ahero Bridge E034.92069ºS00.17211º 3829±2.09 13 √   √  - √   √   √  - - - √   19 Ainamutua-Kibigori E035.05595ºS00.07583º 3965±7.09 12 √   √  - - √   √  - - - - 22 Anopsiwa E035.117937ºN00.02969º 4228±4.03 10 √  - - - - √  - - - - 23 Anopngetuny E035.117467ºS00.02825º 4363±2.89 10 √  - - - - √   √  - - - 26 Kapngorium at Bridge E035.0997ºN00.05356º 6066±3.89 12 √   √  - √   √  - - √  - - 27 Kundos at Bridge E035.06172ºN00.05110º 6080±3.23 12 √   √  - - √  - - √  - - 30 Chebirirkut at Tinderet Dam E035.34793OS00.03673 0  5986±4.73 6 √  - - - - - - √  - - 33 Ahero Irrigation Channel E034.90789ºS00.17173º 3778±2.56 13 √   √   - √   √  - - - √   √   HS -Human Settlement √  - Classified - Not Classified Participatory interviews were held with six Provincial Administration Officers (Chiefs) in Tugunon, Kedowa, Siwot, Koyo, Tinderat-Barasendu and Kobura locations, four scientists (Project manager and three chemists) from LVEMP’s pollution loading component at Kisumu and Kenya Agriculture research Institute (KARI) and six District Agriculture and livestock officers, two each from Kericho, Nandi, and Nyando districts to gather the relevant information regarding roles of their institutions in advising farmers on handling of agrochemical. Also three clinical officers, one each from Londiani, Ahero and Kaptumo sub-district hospitals and 22 pesticide retailers in the urban centres within the catchment four in Londiani, three each in Kedowa, Kipkelion and Ahero; 0ne each in Muhoroni and Chemelil, seven in Nandi Hills and four in Koru. RESULTS The Agricultural Enterprises in Kericho, Nandi and Nyando Districts Agriculture is the most important source of income in Nyando catchments; 82% of the farmers interviewed depend entirely on farming, with the production heavily constrained by rain especially in the lower River Nyando basin. Of the available hectares of arable land in drainage basin, 15% is set aside for cash crops such as tea (6%), sugar cane (4%), pyrethrum (3%) and coffee (2%) documented in Table 2. Maize, which is the staple food, is grown mainly for family consumption; only 17% of the farms also grow maize for sale. The most common food crops grown by households are beans (15%), kales (14%), cabbage (12%), tomatoes (11%), sweet potatoes (8 %), peas (5%), Onions (3%), cassava (2%) and rice (1%). Vegetables are most immediate cash income source. Average income per household ranges from US $ 300 to 1000 per year, but the income can be low during droughts. The food crops occupy 58%, 28% and 49% of the arable land in Kericho, Nandi and Nyando Districts respectively (Table 2). The main cash crops are tea, coffee, and sugar cane which occupy 27%, 11% and 34% of the arable
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