Chemical and biological monitoring in ephemeral and intermittent streams: a study of two transboundary Palestinian–Israeli watersheds

Abstract

Although ephemeral streams constitute critical natural resources in dryland environments, water regulations and monitoring protocols typically focus on perennial streams, and may not always be appropriate for characterizing intermittent systems. The article presents findings from a comprehensive evaluation of environmental conditions in two ephemeral transboundary streams: the Hebron/Besor and Zomar/Alexander. The streams are representative of numerous watersheds which originate in Palestinian land and flow into Israel. Transboundary streams in the region exhibit high concentrations of point and nonpoint sources of pollution. Many of the region's streams that in the past had no flow except for isolated storm incidents have emerged as perennial streams, channelling raw or partially treated industrial or municipal wastes. Management of these natural resources constitutes a unique challenge because of the complex local political circumstances. The article presents chemical and biological monitoring results, identifying high levels of non-point source nutrient runoff during rainfall events and high percolation of contaminated stream water during its flow that should be addressed in future restoration strategies. The practical challenges associated with the monitoring of ephemeral streams are also discussed with suggestions for future studies and management efforts.

Transformation of pharmaceuticals during oxidation/disinfection processes in drinking water treatment

“…Many freshwater resources are significantly impacted by wastewater, to the point that some small rivers and creeks are composed mainly of treated wastewater (up to 100% during dry periods), and in developing countries, also untreated wastewaters. This is the case for natural streams in different regions of the United States [87,88], European countries like Spain [89], England [86], and Sweden [90], as well as India [91] and countries in the Middle East [92] and Africa [93]. Lack of rain concentrates anthropogenic contaminants and also bromide, such that not only chlorine-containing DBPs can be formed in drinking water treatment, but also more toxic bromine-containing ones.…”

High Variability Is a Defining Component of Mediterranean-Climate Rivers and Their Biota

“…An example is the Júcar River Basin in Spain, where part of the biomonitoring network has no biological data available because sampling sites were always dry at the time of sampling [114]. In other cases, such as transboundary Palestinian-Israeli watersheds, the complex political situation restricts the implementation of biomonitoring programs although attempts to adjust biotic indexes have been made [115]. In Chile, biomonitoring programs are not mandatory and are not being fully implemented [116].…”

Erratum: Water quality in non-perennial rivers [Water SA 45 (3) 487–500]

“…The pollution profiles of N-PR basins are becoming similar to watersheds in perennial rivers, which are characterised by point sources and non-point sources. Many non-perennial streams are becoming, or have already become, channels for raw wastewater and treated effluents as sewage treatment procedures in many semi-arid regions move from septic tanks 494 and cesspools to major sewage systems, which affect both the morphology and the water of the stream (Hassan and Egozi, 2001;Tal et al, 2010;Köck-Schulmeyer et al, 2011). Evaporation, which is likely to concentrate toxicants, is an important driver in N-PRs, as are interactions such as changes in pH, or increased temperature, that govern the release and adsorption of toxicants from and to sediments.…”