Exploring the use of indigenous Western Cape plants as potential water and soil pollutant phytoremediators with a focus on green infrastructure

Abstract

Urban water managers, engineers and conservation ecologists in the Western Cape (WC) Province of South Africa are faced with a major environmental and human health challenge, with urbanisation, industrialisation, population growth and agricultural development placing pressure on the limited water and soil resources. In addressing this resource degradation an effective, affordable and sustainable solution is required. The implementation of ‘green infrastructure’ (GI), such as phytoremediation, involves the use of plants to hinder pollutant transport and attenuate runoff flow, protecting the health of the human population and the environment. However, care must be taken when selecting plant species due to possible invasive behaviour, affecting ecosystem dynamics. As a result of the need for resource remediation in both urban and rural areas, the use of non-invasive indigenous species is vital to an efficient and sustainable technology, as urban areas are often the initial sites for introduction from which invasions spread. This paper proposes indigenous WC species for potential use in GI, identified from global bioremediation literature, as an aid to the practicing civil engineer and water manager  responsible for the design and management of the phytotechnology. These indigenous species offer potential as phytoremediators in local GI, as well as suggest the types of plants that should be investigated further as alternatives to effective exotics. The investigation returned 56 non-invasive WC plant species likely to aid resource remediation without jeopardising the conservation and biodiversity of the administered area. The selected vegetation is potentially capable of increasing heterogeneity and adjusting to the dynamic biogeographic conditions of the recipient habitat. Thus, distinct species capable of remediating a wide range of environmental contaminants for GI, into the diverse habitats of the WC, at a fraction of the cost of conventional techniques, are promoted.