Uses and Environmental Pollution of Biocides - Pesticides: Evaluation of Environmental Pollution - page 15

of pesticide poisoning may even be greater than reported due to under-reporting, lack of
data, and misdiagnosis (Wilson and Tisdell 2000).
1.3.2 Environmental Contamination
Pesticides are found at detectable levels in many parts of the environment in the inhabited
as well as noninhabited areas of the world. Some pesticides belong to the POPs class and
contribute to soil contamination. In addition to ecological impacts in countries of applica-
tion, pesticides that have been long banned in developed countries (such as DDT, toxa-
phene, etc.) are consistently found in remote areas such as the high arctic. Chemicals that
are applied in tropical and subtropical countries are transported over long distances by
global air circulation (Ongley 1996). GESAMP (1986) defines environmental (also known as
receiving, absorptive, or assimilative) capacity as “the ability of a receiving system or eco-
system to cope with certain concentrations or levels of waste discharges without suffering
any significant deleterious effects” (Cairns 1977, 1989). All activities, including agriculture
have some level of impact on air, water, and soil quality; the issue is whether the impact
exceeds the thresholds that society deems unacceptable for social, economic, or cultural
reasons. For agriculture, there is a need to determine what the environmental capacity is
for different types of runoff products in the local context (Ongley 1996).
Agriculture, as the single largest user of freshwater on a global basis and as a major cause
of degradation of surface and groundwater resources through erosion and chemical runoff,
has a cause to be concerned about the global implications of water quality. The US EPA
(1994) identified agriculture as the leading cause of water quality impairment of rivers and
lakes in the United States and third in importance for pollution of estuaries. Degradation
of water quality by pesticide runoff has two principal human health impacts. The first is
the consumption of fish and shellfish that are contaminated by pesticides; the second is the
direct consumption of pesticide-contaminated water. WHO (1993) has established drink-
ing water guidelines for 33 pesticides. Many health and environmental protection agencies
have established “acceptable daily intake” (ADI) values that indicate the maximum allowed
daily ingestion over a person's lifetime without appreciable risk to the individual.
There is no doubt that the environmental pollution has become a real global crisis.
The International Code of Conduct on the Distribution and Use of Pesticides (FAO 1985),
along with other important regulations such as the Pesticide Risk Reduction Initiative
of Organization for Economic Co-operation and Development (OECD) and FAO and
Stockholm Convention on POPs, is very relevant to pesticide pollution control and envi-
ronmental protection in general. Many countries all over the world have taken good steps
to control their use of pesticides.
Monitoring of environmental samples is usually done on a regular and routine basis in
developed countries to evaluate the risk to environment. Key pesticides are included in the
monitoring schedule in these countries. In developing countries, basic data about pesticide
releases and environmental contamination levels are missing. Monitoring programs are
limited to some organochlorine pesticides. For example, the low levels of pesticide resi-
dues reported in Egypt reflect good progress made by the country in reducing pesticide
use cit. (Loutfy et al. 2008). The rationale is based on the fact that if aquatic contamination
exists, it will be evident in biota. Canada and the United States have agreed on the use
of biologically based objectives for the management of water quality of the Great Lakes.
These techniques are very useful in developing countries insofar as the measurements
require training in biology (usually good in developing countries) and are labor-intensive