The potential use of plant species within a Renosterveld landscape for the phytoremediation of glyphosate and fertiliser

Abstract

In South Africa, fertiliser and herbicide pollutants resulting from agricultural practices indirectly lead to the degradation of surface freshwater and groundwater quality. Nitrogen and phosphorus, and glyphosate, derived from agricultural fertiliser and herbicide applications, respectively, contribute to watercourse toxicity. Adjacent to many of the surface freshwater systems are some of South Africa’s most productive agricultural lands, where natural ecosystems are converted to croplands, resulting in the degradation of natural vegetation and deterioration of freshwater quality. The critically endangered status of some Renosterveld vegetation types is the product of agricultural expansion, nutrient loading through fertilisation and the spraying of herbicides. A buffer of Renosterveld vegetation along river corridors may contribute to the remediation of agricultural pollutants prior to entering watercourses. The utilisation of wetland plants occurring within Renosterveld for agricultural pollutant extraction can increase river corridor biodiversity, creating indigenous refuges and facilitating habitat connectivity. A laboratory phytoremediation system was designed and constructed to investigate the pollutant-removal potential of indigenous species occurring in Renosterveld vegetation (amongst other areas), compared with commonly used invasive alien plants (IAP) in floating wetland designs. Five pollutant parameters – ammonia, nitrate, orthophosphate and two glyphosate concentrations – reflect environmental stresses on 14 wetland species naturally occurring within Renosterveld vegetation. Effluent analyses indicated significant removal efficiencies for the indigenous vegetation across both fertiliser and herbicide pollutants, with the two most effective species identified as Phragmites australis and Cyperus textilis, with 95.87% and 96.42% removal, respectively. All wetland species displayed greater pollutant removal than the unvegetated soil control and when compared to an IAP and palmiet assemblage, indicated similar pollutant-removal efficiencies, justifying their use as an acceptable alternative.

Isolation, Biochemical and Genomic Characterization of Glyphosate Tolerant Bacteria to Perform Microbe-Assisted Phytoremediation

“…Despite the general and widespread use of glyphosate, its phytoremediation has been poorly investigated. Jacklin et al (2020) evaluated the effects of glyphosate in 14 plant species in constructed wetlands. The planted wetlands removed an average of 96.8% of the 0.7 mg L –1 glyphosate while the unvegetated wetlands (control) removed 92.2%, suggesting the relevance of the glyphosate adsorption to the soil and the need to ensure the local biodegradation.…”

Emerging environmental contaminants: Sources, effects on biodiversity and humans, remediation, and conservation implications

“… Source: Mench et al 50 , 55 Khalid et al 7 , 49 Jacklin et al 6 , 50 , 54 – 56 Kahangwa et al 6 , 50 , 54 – 56 Lee et al 6 , 50 , 54 – 56 and Tindwa and Singh. 39 , 52 , 57 …”

“…heavy metals), obstruct their flow, and prevent interaction with contaminated soils 7 , 49 During the process of phytodegradation, plants take up EECCs from polluted soils, metabolize them, and convert them into volatile organic compounds, less-toxic byproducts, or less-harmful vapors using certain enzymes. 7 , 50 , 55 , 56 In general, phytoremediation trials conducted in previous studies have demonstrated efficacy in eliminating EECCs from contaminated areas. 6 , 50 , 54 – 56 …”

“… 7 , 50 , 55 , 56 In general, phytoremediation trials conducted in previous studies have demonstrated efficacy in eliminating EECCs from contaminated areas. 6 , 50 , 54 – 56 …”

Soil pollution and agriculture in sub-Saharan Africa: State of the knowledge and remediation technologies

“…Phytoremediation of gold tailings-contaminated soils in South Africa using Vetiver grass (Chrysopogon zizanioides) has also been reported (90). Others include use of water hyacinth for bioremediation of water and sediments in the Hartbeespoort Dam, South Africa (91) and Cyperus textilis for phytoremediation of soils contaminated with glyphosate-based herbicide pollutants along the Breede River of the Western Cape Province of South Africa (92).…”