A survey completed last week by the Haifa Technion and the Volcani Institute for the Ministry of Environment points to heavy pollution by organic carbon compounds, ammonia and sulphide in Israel's waterways. The source of these pollutants is household waste and the effluent channelled into the watercourses from water purification plants, and the direct channelling of non-purified effluent into rivers. In a number of places where a main road crosses a river, the survey found a high measure of pollution by hydrocarbons deriving from fuels and oils.
The survey covered the Alexander, Yarkon, Sorek and Lachish rivers. Samplings were taken from the riverbeds, in the autumn and spring months, with a view to learning of the effect of floods and the aggregation of pollutants in the summer months. The Kishon, held to be the worst polluted of Israel's watercourses, was not examined since the Kishon River Authority examined its riverbed a few years ago.
According to Dr. Yeshayahu Bar-Or, manager of the Water and Rivers Division at the Ministry of the Environment, high concentrations of organic carbon, ammonia and sulphide result in a toxic riverbed environment. This prevents the developments of snails and insects that serve as food for fish and other creatures. The result is very bad damage to bio-diversity and the ecological balance in coastal rivers, hindering their rehabilitation. These substances are highly dangerous to flora and fauna. Another finding is that in recent years of drought, no effective process has taken place in which pollutants are washed away from the rivers to the sea, thus further exacerbating the situation.
The survey naturally concludes that steps must be taken to put a stop to the flow of low quality wastewater and effluent to the rivers, while ensuring a much higher level of purification. Bar-Or: The Water and Rivers Division has established very exacting standards for effluent destined to be channelled into rivers, and these standards should be binding upon all the plant operators. The water purification institutes of Kfar Sava, Hod Hasharon, and Haifa were recently given two to four years in which to upgrade the quality of their effluent.
The dubious honour of being graded the most polluted river goes to Nahal Sorek, into which flows the sewage of Rehovot. Rehovot has, in fact, set up a system for joining up to the Dan block sewage treatment plant. However, due to an ongoing dispute with the management of the plant over the price of purification and the duration of the contractual engagement, Rehovot refuses to direct its sewage to the plant, channelling it instead directly into the river. A malfunction that recently surfaced in the pipeline that is supposed to connect the town to the Dan block sewage treatment plant is further delaying the connection. Bar-Or: "This week, a sharply worded letter of warning will be sent to the Rehovot Municipality, requiring them to take emergency measures until the pipeline is rehabilitated".
Some of the news, however, is rather more encouraging. The survey indicates that no heavy metal concentrations were found in these rivers, in contrast to European countries and some American states. Bar-Or: "The reason is that the level of industrialisation in Israel is still lower than European standards. Also as regards sewage sludge, a mixture of organic and inorganic materials derived from purification plants, a lower level of metal was found than is customarily accepted in European countries". According to Bar-Or, another reason for the low quantity of metals is related to enforcement drives held by the Ministry of Environment in recent years in plants in the Tel-Aviv area. The Dan block sewage treatment plant notably consigns the sludge it produces into the sea.
Published by Israel's Business Arena on 2 April, 2000