Environmental degradation related to mining-generated acid mine drainage (AMD) is a major global concern, contaminating surface and groundwater sources, including agricultural land. In the last two decades, many developing countries are expanding agricultural productivity in mine-impacted soils to meet food demand for their rapidly growing population. Further, the practice of AMD water (treated or untreated) irrigated agriculture is on the increase, particularly in water-stressed nations around the world. For sustainable agricultural production systems, optimal microbial diversity, and functioning is critical for soil health and plant productivity. Thus, this review presents up-to-date knowledge on the microbial structure and functional dynamics of AMD habitats and AMD-impacted agricultural soils. The long-term effects of AMD water such as soil acidification, heavy metals (HM), iron and sulfate pollution, greatly reduces microbial biomass, richness, and diversity, impairing soil health plant growth and productivity, and impacts food safety negatively. Despite these drawbacks, AMD-impacted habitats are unique ecological niches for novel acidophilic, HM, and sulfate-adapted microbial phylotypes that might be beneficial to optimal plant growth and productivity and bioremediation of polluted agricultural soils. This review has also highlighted the impact active and passive treatment technologies on AMD microbial diversity, further extending the discussion on the interrelated microbial diversity, and beneficial functions such as metal bioremediation, acidity neutralization, symbiotic rhizomicrobiome assembly, and plant growth promotion, sulfates/iron reduction, and biogeochemical N and C recycling under AMD-impacted environment. The significance of sulfur-reducing bacteria (SRB), iron-oxidizing bacteria (FeOB), and plant growth promoting rhizobacteria (PGPRs) as key players in many passive and active systems dedicated to bioremediation and microbe-assisted phytoremediation is also elucidated and discussed. Finally, new perspectives on the need for future studies, integrating meta-omics and process engineering on AMD-impacted microbiomes, key to designing and optimizing of robust active and passive bioremediation of AMD-water before application to agricultural production is proposed.

In water-scarce areas, the reuse of (un)treated acid mine drainage (AMD) water for crop irrigation has become a requirement, but it also carries a wide range of contaminants that can elicit the synthesis of diverse metabolites necessary for the survival of the plants. There is still a paucity of studies on the impact of quicklime treated-AMD water on the metabolite synthesis of potatoes. This study examined the effect of the irrigation of two potato cultivars (Marykies and Royal cultivars) with quicklime-treated AMD water on their metabolite profiles. A greenhouse study was conducted with five experimental treatments with different solution ratios, replicated three times in a completely randomized design. A total of 40 and 36 metabolites from Marykies and Royal cultivars which include amino acids, organic acids, and aromatic amines were identified, respectively. The results revealed elevation in the abundance of metabolites under the irrigation with treated AMD water for both cultivars with subtle variations. This will provide information on the primary metabolite shifst in potato that enhance their survival and growth under AMD conditions. However, more specific data on toxicity due to AMD irrigation would be required for a refined risk assessment.

This study compared the responses of two potato cultivars, Fianna and Lady rosetta (both determinate and indeterminate), to irrigation with various fly ash: acid mine drainage (AMD) amelioration ratios in two separate seasons. In order to calculate crude protein (CP), the nutritional composition (NC) of potato tuber samples was examined using the combustion method. The results showed that the NC of plants irrigated with AMD mixed with fly ash was significantly affected differently at harvest. In plants exposed to 75% AMD irrigation, the mean moisture content of Lady rosetta was reduced by twice more compared to Fianna. Concisely, our study has demonstrated that irrigation with AMD mixed with fly ash can promote plant growth of potato cultivars and reduce their crude protein (CP) by approximately 4% when irrigated with both 50% FA: AMD and untreated AMD (100% AMD) ratio being applied; nonetheless, it was decreased by 1% when watered with 75% FA: AMD treatment, lipids content, carbohydrates, fresh tuber weight and dry tuber weight. On average, plants from both cultivars irrigated with the 75% AMD had higher fresh tuber weight (FTW), higher dry tuber weight (DTW) and carbohydrates compared to the controls. Furthermore, Lady rosetta cultivar exhibited higher carbohydrate and crude fiber compared to the control at 75 and 50% AMD treatments, respectively. Use of AMD in agriculture is likely to reduce its devastating environmental conditions and assist in irrigation of food crops, thereby alleviating both water and food shortages. Last, all the FA-AMD-treated potatoes had Pb concentrations that were below the minimum standard limits, and this proves that FA was able to adsorb the Pb ions in the tuber samples. Importantly, fly ash reduces a metal’s concentration in AMD. However, presence of heavy metals in such potatoes needs to be explored. It is also important to relate the possible metal intake relative to the standards by World Health Organization (WHO).

Cissus cornifolia (Baker) Planch is traditionally used in South African traditional medicine (SATM) to treat a variety of human infections. The antimicrobial activity of extracts from C. cornifolia was investigated in vitro against a plethora of pathogenic microorganisms using the microdilution assay. The acetone extract exhibited a notable minimum inhibitory concentration (MIC) value of 0.10 mg/mL against Mycoplasma hominis and a further MIC of 0.20 mg/mL against Candida parapsilosis, Streptococcus agalactiae, Pseudomonas aeruginosa, and Enterococcus faecalis. In the antiproliferative assays, both the ethyl acetate and methanol extracts exhibited a potent inhibition of the MCF-7-21 cell line. In the anti-inflammatory assays, both the ethyl acetate and methanol extracts exhibited IC₅₀ values of 15.59 and 15.78 µg/mL against Cyclooxygenase-2 (COX-2), respectively. Methanol extract further exhibited potent dual inhibition of both COX-2 and 15-LOX enzymes, hence, recommended to curb both related cancers, particularly breast cancer and inflammation-borne diseases. In the comparative gas chromatography time-of-flight mass spectrometry (GC/TOF-MS), the acetone, ethyl acetate, and methanol extract contained significantly prevalent amounts of compound 2-(2’,4’,4’,6’,6’,8’,8’-Heptamethyltetrasiloxan-2’-yloxy)-2,4,4,6,6,8,8,10,10-nonamethylcyclopentasiloxane with % area ranging from 15.714 to 39.225. The findings in the current work validates the use of the plant species in SATM in the treatment of cancer-like infections, opportunistic infections associated with HIV-AIDS. Furthermore, the in vivo studies and the mechanisms of action still need to be explored.

In water-scant regions, the reuse of (un)treated acid mine drainage effluent (AMD) water for crop irrigation has turned into a prerequisite. The study assesses the levels of heavy metals, and health risk assessment in two potato crop cultivars, namely, Fianna and Lady rosetta (both determinate and indeterminate) when exposed to irrigation with different fly ash: acid mine drainage amelioration ratios. The study investigates the health risk assessment in the potato tissues namely, stem, tubers, new and old leaves of the potato cultivars. The treatments constituted a control, 50% FA: AMD, 75% FA: AMD ratio, and 100% AMD (untreated AMD). The results showed that the heavy metals of plants irrigated with AMD mixed with FA was significantly affected differently at harvest. In summary, the concentration of Cd was over the WHO acceptable standards in untreated acid mine drainage water. Fianna recorded 1.34 mg/kg while a notably decrease was observed in Lady rosetta with (1.01 mg/kg). In any case, FA was proven to significantly lessen the Cd particles in both FA-AMD ratios: Cd content was 0.98 mg/kg and 0.84 mg/kg in 50% FA: AMD treatment for Fianna and Lady rosetta separately, while the recommended maximum limit is 0.1 mg/kg. With the readings recorded, they are slightly high according to the CODEX general standard for food contaminants and toxins in food and feed (CODEX STAN 193-1995). Then again, in 75% FA: AMD ratio, the Cd concentration was 0.04 mg/kg and 0.03 mg/kg for Fianna and Lady rosetta exclusively. It is in this way obvious that FA adsorbed the Cd ions, and the two cultivars fulfill the CODEX guideline, nonetheless the potato crop irrigated with a 75% FA: AMD ratio can be consumed by humans without causing any detrimental effects.

In water-stressed regions, the use of treated acid mine drainage (AMD) water for irrigated agriculture has been suggested as an alternative to address the shortage of fresh water sources. However, the short and long-term impact of using such (un)treated AMD water on soil health, particularly the microbiome structure and functional capacity, is not known. We present high-throughput amplicon sequence (HTS) datasets of purified microbial metacommunity DNA of soils under Irish potato production irrigated by quicklime and fly ash treated AMD water. The irrigation treatments included quicklime treated AMD water (A1Q and A2Q; n = 16), and quicklime and fly ash-treated AMD water (AFQ; n = 5), untreated AMD water (uAMD; n = 7) and control group using tap water (n = 5). The V1-V3 hypervariable region of the 16S rRNA gene from each sample were sequenced on an Illumina MiSeq to generate these HTS datasets. The raw sequences underwent quality-checking, demultiplexing into FASTQ files, and processing using MOTHUR pipeline (v1.40.0). Th quality reads classified into taxonomic ids (phylum, class, order, family, and genus) using the Naïve Bayesian classifier algorithm against the SILVA database (v132) and were assigned to operational taxonomic units (OTUs) based on the pairwise distance matrix (Euclidean distance matrix). The applicability of the HTS datasets was confirmed by microbial taxa at the phylum level. All HTS datasets are available through the BioSample Submission Portal under the BioProject ID PRJNA974836 (https://www.ncbi.nlm.nih.gov/bioproject/974836).