Environmental Engineering Reference
In-Depth Information
the Board (Otieno 2009). However, our experience 'on-the-ground' indicates a distinct lack of
monitoring by the Board and other authorities to ensure that experienced personnel are handling/
applying carbofuran and to deter misuse.
Unfortunately, most Kenyan farmers lack the basic knowledge of the inherent risks of han-
dling and applying pesticides, which often leads to indiscriminate use, incidental exposure, exces-
sive application and an inability to identify banned or restricted products (Wandiga, Lalah and
Kaigwara 2002). This situation is not helped by the fact that many of the banned products none-
theless fi nd their way back onto store shelves and become available once more to farmers. Faced
with many products on the market, several factors tend to infl uence a farmer's choice, including
the prices of the products available, the formulation (whether liquid, granular or powder), the
physicochemical properties of the formulation (e.g., smell) and how it is delivered (often by
public transportation, which is more convenient for people in rural areas; Wandiga, Lalah and
Kaigwara 2002). They may be swayed/advised by agricultural extension offi cers or by success-
ful and more 'knowledgeable' farmers, or they can simply be compelled to purchase a pesticide
because of the container it is sold in (e.g., if it can be reused for other purposes). Most farmers
store their pesticides with other household goods or farm produce. Kimani and Mwanthi (1995)
reported that some community members rinse empty pesticide containers at community water
sites, which could lead to severe poisoning and contamination of drinking water sources (although
no such incidents have been documented).
Tractor-mounted sprayers and knapsack sprayers are amongst the most commonly used applica-
tors. Aircraft-mounted sprayers are most often used to control outbreaks of army worms, tse tse
fl ies or locusts (Wandiga, Lalah and Kaigwara 2002). Cattle dips are widely used for treatment with
pesticides, but livestock may also be sprayed using '
jua kali
' (i.e., unorthodox) methods such as fl y
whisks, specially bound leaves and brooms (Nyaga 1988). Those who spray, mix pesticide solutions
or clean up after pesticides have rarely worn protective clothing, mainly because of its cost, but also
because it is uncomfortable in the temperature and humidity. Because the effects of pesticides are
delayed in people, symptoms tend not to be attributed to pesticide exposure and hence, go undiag-
nosed and largely untreated (Nyaga 1988).
3.2.4 General trends in use of pesticides in agricultural communities
This section briefl y considers other pesticides and pesticide use patterns in Kenya. The annual
Provincial and District Agriculture reports, kept in the archives of the two departments at their head-
quarters (the Ministry of Agriculture library located at Agriculture House in Nairobi), contain a
wealth of historical information regarding the various agricultural and veterinary pesticides and their
use at the farm level. These records chronicle the use of pesticides in Kenya over the last few dec-
ades, both for agricultural and veterinary purposes, and generally indicate an increase in the amounts
of pesticides imported annually (see Table 3.1).
Lindane was fi rst introduced in 1949, toxaphene in 1950, DDT in 1956 and dieldrin in 1961.
Other compounds introduced in the 1950s include dinitrocresol (DNC, used as an herbicide and fun-
gicide) and organophosphates such as: tetraethyl pyrophosphate (TEPP), schradan, dioxathion and
coumaphos (Keating 1983). In the last decade, compounds such as aldrin, endrin, endosulfan, tri-
chlorphon, malathion, parathion, dimethoate, fenitrothion, diazinon, chlorfenvinphos, chlorpyrifos,
dichlorvos, polythion, carbaryl, carbosulfan, cypermethrin, deltamethrin, lambda-cyhalothrin, diu-
ron, 2,4-D, atrazine, alachlor, glyphosate and hexazinone have also made their way into the Kenyan
market (Lalah 1994; Wandiga, Lalah and Kaigwara 2002).
The use of many of these pesticides, particularly by large-scale farmers, enabled control of a
vast number of tropical agricultural pests and serious insect and tick-borne diseases in livestock
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