GROUNDWATER POLLUTION BY
NITROGEN COMPOUNDS
IN ISRAEL
CHEN SALITERNIK
Tahal Water Planning Ltd., 54 Rechov Ibn Gabirol, Tel Aviv, Israel
INTRODUCTION
About 70 percent of Israel's water resources is groundwater, concentrated in two main
aquifers: the coastal aquifer consisting of calcareous sandstone and pleistocene sand
formations, and the inland aquifer consisting of cenomanian-turonian limestone and
dolomite. The two aquifers are separated by thick layers of clayey marl and can therefore
be regarded as distinct hydrological units.
The coastal aquifer underlies an area 140 km long and 10 to 20 km wide, and supplies
some 230 MCM — about 30 percent of the country's groundwater supply — annually. The
aquifer is relatively shallow; its depth varies from 0 to 180 m. Most of the wells reach a
depth of about 100 m. The watertable is commonly at a depth of about 70 m.
The high rate of exploitation of the water resources in the coastal plain, the
population density, its intensive agriculture, and the geological structure cause the coastal
aquifer to be particularly sensitive to pollution. In recent years there have been reports of
a serious increase in nitrate concentrations. It is feared that this accelerated pollution may
cause deterioration of groundwater quality to a degree which will limit its use, especially
as all forecasts on agricultural and urban development point to an increasing rate of
contribution of potential pollutants. This situation is fraught with grave dangers for the
national water balance.
In view of these facts, it was decided to carry on follow-up and research studies on the
processes of groundwater pollution in Israel, and especially of the coastal aquifer. The
abstract here presented deals only with pollution of groundwater by nitrates and included
a general description of the research and its most important findings.
AIMS OF THE RESEARCH
The research aims are the following:
(i) Definition of the sources of nitrate pollutants-and their potential contribution,
(ii) Updated figures on nitrate concentrations in groundwater.
(iii) Understanding of the processes in the soil and the aquifer which have a bearing on
groundwater pollution by nitrates,
(iv) Forecasts of the rate of increase in nitrate concentrations in groundwater.
(v) Application of the accumulated knowledge to the prevention of pollution by
nitrates or to slowing down its rate.
171
NITROGEN COMPOUNDS
IN ISRAEL
CHEN SALITERNIK
Tahal Water Planning Ltd., 54 Rechov Ibn Gabirol, Tel Aviv, Israel
INTRODUCTION
About 70 percent of Israel's water resources is groundwater, concentrated in two main
aquifers: the coastal aquifer consisting of calcareous sandstone and pleistocene sand
formations, and the inland aquifer consisting of cenomanian-turonian limestone and
dolomite. The two aquifers are separated by thick layers of clayey marl and can therefore
be regarded as distinct hydrological units.
The coastal aquifer underlies an area 140 km long and 10 to 20 km wide, and supplies
some 230 MCM — about 30 percent of the country's groundwater supply — annually. The
aquifer is relatively shallow; its depth varies from 0 to 180 m. Most of the wells reach a
depth of about 100 m. The watertable is commonly at a depth of about 70 m.
The high rate of exploitation of the water resources in the coastal plain, the
population density, its intensive agriculture, and the geological structure cause the coastal
aquifer to be particularly sensitive to pollution. In recent years there have been reports of
a serious increase in nitrate concentrations. It is feared that this accelerated pollution may
cause deterioration of groundwater quality to a degree which will limit its use, especially
as all forecasts on agricultural and urban development point to an increasing rate of
contribution of potential pollutants. This situation is fraught with grave dangers for the
national water balance.
In view of these facts, it was decided to carry on follow-up and research studies on the
processes of groundwater pollution in Israel, and especially of the coastal aquifer. The
abstract here presented deals only with pollution of groundwater by nitrates and included
a general description of the research and its most important findings.
AIMS OF THE RESEARCH
The research aims are the following:
(i) Definition of the sources of nitrate pollutants-and their potential contribution,
(ii) Updated figures on nitrate concentrations in groundwater.
(iii) Understanding of the processes in the soil and the aquifer which have a bearing on
groundwater pollution by nitrates,
(iv) Forecasts of the rate of increase in nitrate concentrations in groundwater.
(v) Application of the accumulated knowledge to the prevention of pollution by
nitrates or to slowing down its rate.
171