Agriculture Reference
In-Depth Information
(Castro, 1993; Infante and Sosa, 1994; MEM-DGAA, 1997; Bedregal et al,
2002). In addition, the disorderly growth of human settlements around areas
of crop production - where 35 per cent of the vegetables marketed in Lima are
produced - aggravates this situation, contaminating the horticultural products
with enteric pathogens (Castro and Sa´ enz, 1990; Moscoso and Leo´ n, 1994;
Moscoso, 1998; Acosta et al, 2001; Manrique et al, 2002a, b).
To date, it has not been clear whether vegetable production sites irrigated
with contaminated water have also been affected by heavy metals (HM) and
enteric pathogens to the same magnitude. Information about plant uptake of
HM, patterns of water quality in the river basin and causes and sources of
contaminants are lacking, as well as farmers' awareness of the risks inherently
involved in their work. Furthermore, there are significant public health risks
associated with food consumption where urban agriculture (UA) and peri-urban
agriculture (UPA) use contaminated water. Given the lack of information on
related health risks, this study was initiated to assess and provide guidance to
stakeholders at different levels, from producers to consumers.
Research objectives
This research involved an analysis of HM and fecal contamination in the
Rı´ mac River basin to determine the environmental risks and the impact on
soil, water and vegetables in the eastern part of Lima. The objectives of the
present study were to first study historical data (spatial and temporal) on the
quality of water in the basin. The specific objectives were to document and
analyse the sources of pollution in the river basin both currently and in the
past; to map the spatial distribution of HM and fecal contamination in the
entire Rı´ mac River basin using secondary data; and to determine whether
municipal and national environmental regulations have influenced a reduction
in the pollution.
The second major objective was to evaluate existing environmental risks
affecting agricultural land, water and vegetables produced. Specifically, the
study aimed to understand farmers' perceptions concerning water quality used
in vegetable irrigations; to characterize the actual levels of HM and fecal
contamination in water located both in the main weir and irrigation canals; to
determine the environmental risks due to the absorption of HM in the soil
and the risks to human health due to concentrations of HM and fecal
contamination in vegetables; and to propose recommendations to improve the
quality of agriculture products.
M
ETHODS
Assessment of historical water quality of the R´mac River
Sources of information
HM such as arsenic (As), cadmium (Cd), chromium (Cr) and lead (Pb) were
selected because they are known to be contaminants that can be absorbed by
