Latest Submission

Stampriet Transboundary Aquifer System (STAS) – Governance of Groundwater Resources in Transboundary Aquifers (GGRETA) Project

Documentation: A read-only folder structure of all reports, data, and models related to the STAS can be accessed from here: Read more

Support to Phase 3 of the ORASECOM Basin-wide Integrated Water Resources Management (IWRM) – Plan: Overview

Overview The main objectives of this consultancy were to undertake scenario analyses, economic, water requirement projection and ecological support studies Read more

Water Resources Quality Joint Basin Surveys (JBSs)

The second 5-yearly comprehensive Joint Basin Survey (JBS2) of the quality of the water resources of the Orange-Senqu River Basin was undertaken Read more

2014 Integrated Water Resources Management Plan (IWRMP) – Summary and Documents

Purpose: This article will provide an overview of the 2014 IWRMP and provide links to the actual documents Related WIS Read more

  • WIS > Biota and Ecosystems > POPs, PAHs and elemental levels in sediment, fish and wild bird eggs in the Orange–Senqu River Basin

POPs, PAHs and elemental levels in sediment, fish and wild bird eggs in the Orange–Senqu River Basin


Four southern African countries, Lesotho, South Africa, Botswana, and Namibia share the basin of the Orange-Senqu River and are Parties to the Stockholm Convention (SC) on Persistent Organic Pollutants (POPs). Currently, the SC targets 21 chemicals and classes of chemicals. Previously, the research in the Orange-Senqu Basin on POPs concentrated on pesticide POPs such as DDT. Only recently has more attention been given to POPs such as dioxins and PBDEs. Almost nothing is known about PAHs in the catchment, except for a recent Water Research Commission survey.

There are also very few studies available on elemental levels in sediments. This study undertook a survey and assessment of POPs and heavy metals in water bodies and riverine sediments as contribution to the Transboundary Diagnostic Analysis (TDA) of the orange-Senqu River Basin. During the study, polycyclic aromatic hydrocarbons (PAHs) were added as additional research
topic. The entire Orange-Senqu River catchment was targeted for sediment collection and 61 sites were sampled in South Africa in September 2010. Of the 61 sites, 33 were in the Vaal River catchment. The remaining 28 sites were Orange-Senqu River sites that did not drain into the Vaal River. One site was in Namibia and five from Lesotho. These sites largely conform to the sites used
by other components of the TDA. Fish and wild bird eggs were sampled in South Africa to investigate the levels of the compounds and elements in the biota of the Orange-Senqu River Basin.

Funding Organisation(s):

Global Environment Facility through United Nations Development Programme


ArcReader Database

The results from this project was captured in an ArcReader Map format. The ArcReader Software can be downloaded from ESRI. The maps and data can be downloaded here.

POPs ArcReader Maps

POPs ArcReader Maps

Monitoring Sites

Sediment Monitoring Sites

Sediment Monitoring Sites

Wild Birds and Fish Sites

Wild Birds and Fish Sites


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