Application of Solid Phase Adsorption Toxin Tracking Technology (SPATT) for Monitoring Microcystins in farm dams. Farm Dams data, Levubu, 0929, Limpopo Province, S.A (LATITUDE: -23.09234 LONGITUDE: 30.2754).

South Africa (S.A) is water scarce and has extremely limited water resources. In S.A, freshwater resources are increasingly being affected by eutrophication and HABs. Irrigation of edible plants with cyanobacteria-containing water may pose a threat of indirect exposure of humans to cyanotoxins via bioaccumulation of these toxins in plant tissues. The current study aimed to assess the applicability of SPATT as an early warning tool for the passive sampling of microcystins (MCs) in farm dams around the Levubu area in Limpopo Province and determine the physicochemical parameters that correlate to toxin loads in the farm dams. Three farm dams being fed by Mambedi, Luvuvhu and Lotonyanda rivers were selected and sampled monthly from June to November 2021. Physicochemical parameters monitored included EC, pH, Temperature, TDS, turbidity, chlorophyll-a and total dissolved nitrates and phosphates. A Benchtop Flow-Cam was used to identify cyanobacterial species. Microcystins from grab and SPATT samplers were quantified using the ELISA method. Findings showed that, except for the months of October and August, the pH was within the DWAF (1996) guideline for irrigation water and within the range optimal for cyanobacterial growth. EC and TDS were all within the DWAF (1996) guideline and within optimal range for the growth of cyanobacteria. Except in the month of June, the water temperatures were all above 20oC and optimal for the growth of cyanobacteria. The levels of nutrients where in most cases below the detection limit and in very low levels to support cyanobacterial growth. Chlorophyll-a was also low, indicating oligotrophic to mesotrophic eutrophic status of the rivers. Among HABs identified were Microcystis and Lyngbya genus. Both grab and SPATT samplers detected MCs in all the farm dams throughout the sampling period and there was a similar pattern in their detection of MCs, even though there was no correlation between the MC levels detected by these two methods. None of the physicochemical parameters monitored correlated with cyanobacterial biomass and MC levels both in grab and SPATT samples. The use of SPATT increased the likelihood of detecting MCs thus indicating that SPATT can be a useful tool for giving early warning of MCs presence to the water users.