Author(s):
Sousa, Pedro Leão de 
; Cerejeira, Maria José ; Silva, Emília ; Batista, Sofia ; Ribeiro, Luís ; Paralta, Eduardo ; Mendes, Maria Paula
Date: 2008
Persistent ID: http://hdl.handle.net/10400.5/1028
Origin: Repositório da UTL
Subject(s): Tagus vulnerable zone; nitrates; pesticides; probability maps; zona vulnerável do Tejo; nitratos; pesticidas; mapa de probabilidades
Description
Taking in account the hydrogeologic
characteristics and the intensive agricultural
occupation, on 3rd September of 2004, through
Portaria 1100/2004, the Northern Tagus
alluvium was defined vulnerable zone to
diffuse pollution with nitrates from agricultural
source (ZVT). This region enclosing Golegã,
Alpiarça, Santarém, Chamusca, Vila Nova da
Barquinha, Constância and Torres Novas
councils, has an approach area of 19124 ha
not integrating the Paúl de Boquilobo
protection area.
Currently, ZVT is to be studied in the scope
of the project AGRO 530 entitled “Intervention
Plan and Support Decision System
Development for the Northern Tagus Alluvium”.
With the beginning in July of 2004,
the institutions “Instituto Superior de Agronomia”
(ISA) (Coordination), “Instituto Superior
Técnico” (IST) and “Direcção Regional
de Agricultura do Ribatejo e Oeste” (DRARO)
participate in this project.
From the moment that an area is designed
as vulnerable zone, one of the procedural
obligations is the elaboration of an action plan(according to the Decree-Law 235/97, article
7º). One of the objectives of this project is to
contribute for one correct implementation of
the plan towards a sustainable and socially
acceptable agriculture.
The work, that now is presented, intends
to divulge the outlines of this project. The
results already obtained on the groundwater
quality in the vulnerable zone, mainly concerning
nitrates and pesticides contamination,
show that in the involving areas of Golegã,
Azinhaga and Chamusca occur nitrates levels
much higher than parametric value of 50 mg/
l of NO3
- , and that in a total of 89 groundwater
samples, collected in 2004, in 27% were
detected at least one of the pesticides and/or
metabolites, being that, in 146 groundwater
samples collected in 2005, the detection
frequency of, at least, on pesticide and/or
metabolite, it was of 38%.
These results reinforce the development
need of support decision systems, particularly
for the sustainable nitrogen fertilizer and
pesticide use in the main cultures of the ZVT.
