Acta agriculturae Slovenica, 121/4, 1–8, Ljubljana 2025 doi:10.14720/aas.2025.121.4.23895 Original research article / izvirni znanstveni članek The effectiveness of bluemink (Ageratum houstonianum Mill.) and French marigold (Tagetes patula L.) in removing Zn and Cu from contaminated growing media Senad MURTIĆ 1, 2, Adi MEŠANOVIĆ 1, Jasna AVDIĆ 1, Alka TURALIJA 3, Amila ISAKOVIĆ 1, Adnan HADŽIĆ 1 Received September 22, 2025; accepted October 17, 2025 . Delo je prispelo 22. september 2025, sprejeto 17. oktober 2025 1 University of Sarajevo, Faculty of Agriculture and Food Sciences, Department for Plant Production, Sarajevo, Bosnia and Herzegovina 2 Corresponding author Email: murticsenad@hotmail.com 3 Josip Juraj Strossmayer University of Osijek, Faculty of Agrobiotechnical Sciences, Department of Agricultural Technics, Osijek, Croatia The effectiveness of bluemink (Ageratum houstonianum Mill.) and French marigold (Tagetes patula L.) in removing Zn and Cu from contaminated growing media Abstract: Utilizing ornamental plants for phytoremedia- tion provides multiple benefits: they enhance the visual attrac- tiveness of their surroundings and are predominantly non-edi- ble, thus decreasing the chances of bioaccumulation in the food chain. To assess the effectiveness of bluemink (Ageratum hous- tonianum Mill.) and French marigold (Tagetes patula L.) in re- moving Zn and Cu from artificially contaminated substrates, a 6-week pot experiment was conducted in a greenhouse. The ex- periment consisted of four contamination treatments for each heavy metal examined, specifically 0, 100, 250, and 500 mg kg-1 for Zn, and 0, 50, 100, and 200 mg kg-1 for Cu. The Zn and Cu levels in the plant samples were determined by atomic absorp- tion spectrophotometry. The bioaccumulation factor (BF) and translocation factor (TF) were used to evaluate the phytoex- traction potential of the plants. BAF values for Zn ranged from 0.739 to 1.089 in bluemink and from 0.534 to 1.047 in French marigold, suggest that both plants analysed could be regarded as potential hyperaccumulators of Zn, particularly in the case of their long-term cultivation on contaminated soil. The BAF and TF values for Cu in both studied plants, bluemink and French marigold, were consistently below 1, indicating their limited ca- pacity to remove Cu from the soil. Key words: heavy metals, ornamental plants, phytoreme- diation, pollution Učinkovitost modrika (Ageratum houstonianum Mill.) in rjavkaste žametnice (Tagetes patula L.) pri odstranjevanju Zn in Cu iz kontaminiranih rastnih medijev Izvleček: Uporaba okrasnih rastlin za fitoremediacijo prinaša več prednosti: povečajo vizualno privlačnost okolice in so pretežno neužitne, s čimer se zmanjšajo možnosti bioaku- mulacije v prehranski verigi. Za oceno učinkovitosti modrika (Ageratum houstonianum Mill.) in rjavkaste žametnice (Tagetes patula L.) pri odstranjevanju Zn in Cu iz umetno onesnaženih substratov je bil v rastlinjaku izveden 6-tedenski lončni poskus. Poskus je obsegal štiri obravnavanja onesnaževanja z vsako preučevano težko kovino in sicer 0, 100, 250 in 500 mg kg-1 za Zn ter 0, 50, 100 in 200 mg kg-1 za Cu. Vsebnost Zn in Cu v vzorcih rastlin je bila določena z atomsko absorpcijsko spek- trofotometrijo. Bioakumulacijski faktor (BF) in translokacijski faktor (TF) sta bila uporabljena za oceno fitoekstrakcijskega po- tenciala rastlin. Vrednosti BAF za Zn so se gibale od 0,739 do 1,089 pri modriku in od 0,534 do 1,047 pri rjavkasti žametnici, kar kaže na to, da bi lahko obe analizirani rastlini obravnavali kot potencialni hiperakumulatorki Zn, zlasti v primeru njune- ga dolgotrajnega gojenja v onesnaženih tleh. Vrednosti BAF in TF za Cu v obeh proučevanih rastlinah, modriku in rjavkasti žametnici, so bile dosledno pod 1, kar kaže na njuno omejeno sposobnost odstranjevanja Cu iz onesnaženih tal. Ključne besede: težke kovine, okrasne rastline, fitoreme- diacija, onesnaženje Acta agriculturae Slovenica, 121/4 – 20252 S. MURTIĆ et al. 1 INTRODUCTION Soil heavy metal pollution is a significant environ- mental issue that poses substantial risks to plant life, hu- man health, and the food supply on a global scale (An- gon et al., 2024). Arsenic (As), mercury (Hg), cadmium (Cd), chromium (Cr), and lead (Pb) are considered pri- ority metals of public health importance because of their high toxicity. However, essential heavy metals such as zinc (Zn) and copper (Cu) can also be toxic to plants, humans and animals when present in the environment above threshold concentrations (Kolesnikov et al., 2021). An excess of Zn in plants leads to a range of mor- phological and physiological disorders, including re- duced growth, smaller leaves, and a weakly developed root system. Furthermore, an excess of Zn in plants ad- versely affects Fe absorption and is also one of the causes of nitrogen deficiency in plants (Balafrej et al., 2020). Excessive intake of Zn can lead to health complications in humans, with symptoms that may include nausea, diz- ziness, headaches, stomach pain, vomiting, and a lack of appetite (Schoofs et al., 2024). The functioning of plants is also compromised due to elevated levels of Cu accumulation. Excessive Cu can damage root cells, inhibit the formation of root hairs, and hinder nutrient and water uptake, interfering with essen- tial physiological processes in plants, particularly pho- tosynthesis (Chen et al., 2020). Additionally, high levels of Cu in plants lead to oxidative stress by catalysing oxi- dation-reduction reactions that produce reactive oxygen species, including singlet oxygen (O2 −), hydrogen perox- ide (H2O2), and hydroxyl radical (OH −). Cu can also bind to sulfhydryl groups in enzymes, inhibiting their activity and disrupting the metabolic pathways in which these enzymes are involved (Permyakov, 2021). Excessive cop- per in the human body can also be harmful, resulting in liver damage, kidney disorders, and other serious health risks (Binesh & Venkatachalam, 2024). Considering the adverse effects of Zn and Cu on both plant and human health, there has been a notable increase in ecological and global public health concerns in recent years regarding environmental contamination by these heavy metals. In light of the above, the effective remediation of soil contaminated with Zn and Cu is of great importance for protecting human health, maintain- ing ecosystems, and ensuring sustainable land use. Currently, phytoremediation is recognized as the most cost-efficient and environmentally sustainable tech- nique for the remediation of soil contaminated by heavy metals (Yan et al., 2020). This is mainly because physi- cal and chemical remediation techniques are complex regarding implementation and costs (Sánchez-Castro et al., 2023). Among phytoremediation processes, phytoextrac- tion is regarded as the most efficient method for remov- ing heavy metals from polluted soils. Typically, it utilizes plants characterized by rapid growth, large biomass, a well-developed root system, tolerance to heavy metal toxicity, and a high capacity for accumulating heavy met- als in their above-ground parts (Rosariastuti et al., 2019). Plant species exhibiting these characteristics are called hyperaccumulators (Sharma et al., 2023). The plants’ ability to remove heavy metals from pol- luted soils varies among plant species, depending mainly on their genetic background and on the soil’s physical and chemical properties that influence heavy metal avail- ability (Park & Oh, 2023). Despite the major progress in phytoextraction research, the implementation of this technique with ornamental plants has not been exten- sively investigated. Using ornamental plant species for phytoremediation offers numerous advantages: they en- hance the beauty of the area they occupy, and are mostly non-edible, thus reducing the risk of biomagnification and bioaccumulation in the food chain (Al-Sayaydeh et al., 2022). In light of the above, this study aims to explore the potential of two ornamental plants: bluemink (Agera- tum houstonianum Mill.) and French marigold (Tagetes patula L.) in removing Cu and Zn from artificially con- taminated growing media. 2 MATERIALS AND METHODS 2.1 EXPERIMENTAL DESIGN The pot experiment was performed from mid-May until June 2025 in a greenhouse of the Faculty of Agricul- ture and Food Sciences, University of Sarajevo, Sarajevo, Bosnia and Herzegovina. On May 12, 2025, one-month- old seedlings of bluemink (Ageratum houstonianum ‘Blue Hawaii’) and French marigold (Tagetes patula ‘Aurora Or- ange’) were placed into plastic pots with dimensions of 12 cm x 10.8 cm and 11 cm x 9.5 cm, respectively. These pots were previously filled with a commercial growing sub- strate (Garden Centre ‘Flora’) artificially contaminated with Zn and Cu. Only healthy seedlings of similar height were chosen for transplantation. The substrate composi- tion selected was a mixture of coconut fibre, black and white peat, composted plant material, organic matter, and perlite, incorporating 1 g of fertilizer N-P-K 15-15- 15 per litre of substrate. According to the manufacturer’s specification, the main chemical properties of the grow- ing substrate before adding the contaminants were as follows: pH (KCl): 6.0, organic matter content: 56 % by mass, available phosphorus: 37.6 mg 100 g-1, and avail- Acta agriculturae Slovenica, 121/4 – 2025 3 The effectiveness of bluemink ... French marigold (Tagetes patula L.) in removing Zn and Cu from contaminated growing media able potassium: 43.2 mg 100 g-1. The total forms of Zn and Cu were 56.2 mg kg-1 and 18.7 mg kg-1, respectively. Before the initiation of the experiment, the substrate with a moisture content ranging from 60 % to 65 % was divided into eight equal parts. Subsequently, 2 kg from each part of the substrate was transferred into individual polystyrene containers. Each container was then spiked with 200 ml of an aqueous solution of ZnSO4·7H2O or CuSO4·5H2O, formulated to reach final concentrations of 0, 100, 250, and 500 mg kg-1 for Zn, and 0, 50, 100, and 200 mg kg-1 for Cu in the substrate. Thorough mixing was then conducted to ensure an even distribution of the heavy metal solution. Following this, the contaminated substrate was transferred into plastic pots, each with a capacity of approximately 0.5 l, which were utilized in the experiment. The experiment consisted of four contamination treatments for each heavy metal examined, specifically 0, 100, 250, and 500 mg kg-1 for Zn, and 0, 50, 100, and 200 mg kg-1 for Cu, with three replications for each treatment. Each contamination treatment included four groups, each containing three pots, resulting in 72 pots for ev- ery plant species analysed. During the experimental pe- riod, the air temperature varied between 18 °C and 33 °C, while the relative humidity fluctuated from 55 % to 95 %. Air circulation was maintained by opening the roof vents and the main entrance throughout the day, while a green shade cloth was used to avoid overheating on hot days. Each plant/pot was watered every 2-3 days to main- tain a steady moisture level in the substrate. At the end of the experiment, 40 days post-setup, the selected plant morphological parameters were measured: plant height, leaf number, inflorescence number, and fresh and dry mass of root and aerial parts. Following this, the plants were harvested and divided into their underground and aerial parts to assess the bioaccumulation and translo- cation factors. The plant’s height was measured using a ruler, whereas the number of leaves and inflorescences was determined by counting. The fresh mass of both the root and above ground parts was measured right after harvesting, while the dry mass was determined after dry- ing in an oven at 60 °C to constant mass. 2.2 EXTRACTION AND ANALYSIS OF ZINC AND COPPER FROM PLANT SAMPLES For the extraction of Zn and Cu from plant samples, the dry ashing digestion method was utilized (Lisjak et al., 2009). In brief, a 2 g dry plant material was placed in a crucible and subjected to ignition in a muffle fur- nace at 550 °C for six h. The ash obtained was then di- gested with 10 ml of a mixture of HNO3 and H2SO4 in a 2.5:1 ratio, and subsequently heated on a hot plate under a fume hood for one h at 60 °C. After cooling to room temperature, the digested plant sample was filtered through Whatman quantitative filter paper No. 42 into a 50 ml volumetric flask and then diluted to the mark with deionized water. Concentration of Zn and Cu in the digested plant samples was measured using a Shimadzu atomic absorption spectrometer (Model 7000-AA, To- kyo, Japan) in accordance with the ISO 11047 method (ISO, 1998). The working standard solutions containing Zn and Cu were prepared by diluting the stock solutions (1000 mg l-1) with deionized water as necessary. 2.3 BIOACCUMULATION FACTOR AND TRANS- LOCATION FACTOR The Zn and Cu concentrations recorded were used to estimate the bioaccumulation factor (BAF) and the translocation factor (TF). BAF was calculated from the metal concentration ratio of the plant’s harvestable part to the growing substrate (Ladislas et al., 2012): TF was evaluated from the ratio of heavy metals in the plant’s above-ground part to that in the plant root (Bonanno et al., 2018): Plants with BAF and TF values both higher than 1 have the potential to be used for phytoextraction (Al- ghamdi & El-Zohri, 2024). 2.4 STATISTICAL ANALYSIS Statistical analyses were carried out using SPSS 20 software. The data were subjected to analysis of variance (ANOVA), and Fisher’s LSD post hoc test determined differences in means at a 5 % significance level (p ≤ 0.05). Results were expressed as mean ± standard deviation (SD). 3 RESULTS The study’s findings demonstrated that the con- tamination of the growth substrate with Zn and Cu Acta agriculturae Slovenica, 121/4 – 20254 S. MURTIĆ et al. had no negative impact on the morphological traits of bluemink and French marigold plants, regardless of the level of substrate contamination. There were no consid- erable differences in the morphological characteristics of the heavy metal-treated plants compared to the control plants (Tables 1 and 2). In addition, throughout the entire experimental pe- riod, no visual signs of heavy metal toxicity were found in the tested plants, suggesting that bluemink and French marigold can grow successfully in growth substrates en- riched with Zn and Cu. For a plant to be deemed to have significant phy- toremediation potential, it should not only be able to suc- cessfully grow in soils that are contaminated with heavy metals but also have a strong ability to accumulate one or more heavy metals in large amounts from these polluted soils. The average values of Zn and Cu in the roots and above-ground parts of bluemink and French marigold plants grown in substrates with varying degrees of Zn and Cu contamination are presented in Tables 3 and 4. The data presented in Tables 3 and 4 indicate that the accumulation of Zn and Cu in both the above-ground and below-ground parts of the bluemink and French marigold plants increased with higher concentrations of these elements in the growing substrate. In addition, Zn and Cu levels have consistently been higher in the roots than in the above-ground parts of the plant, regardless of the level of substrate contamination to which the Treatment Plant height (cm) Above-ground fresh mass (g) Fresh root mass (g) Number of inflores- cences per plant Number of leaves per plant Zn 100 mg kg-1 13.4 ± 1.1 10.6 ± 0.8 1.2 ± 0.4 36.4 ± 3.5 246.7 ± 25.2 Zn 250 mg kg-1 13.2 ± 1.0 10.5 ± 0.8 1.3 ± 0.2 37.2 ± 3.2 232.3 ± 47.6 Zn 500 mg kg-1 12.9 ± 1.1 10.0 ± 0.9 1.1 ± 0.3 34.6 ± 4.2 218.2 ± 27.8 Control 13.5 ± 0.9 10.6 ± 0.7 1.3 ± 0.2 37.1 ± 3.2 241.9 ± 34.8 F test n.s. n.s. n.s. n.s. n.s. Cu 50 mg kg-1 14.1 ± 1.9 11.2 ± 1.5 1.2 ± 0.4 35.7 ± 4.1 241.3 ± 14.9 Cu 100 mg kg-1 13.1 ± 1.5 10.5 ± 1.1 1.2 ± 0.3 36.2 ± 4.5 234.4 ± 13.1 Cu 200 mg kg-1 12.7 ± 2.6 10.3 ± 1.4 1.0 ± 0.4 32.7 ± 5.3 227.4 ± 23.5 Control 13.6 ± 1.3 10.8 ± 1.1 1.1 ± 0.2 35.5 ± 3.7 242.2 ± 13.9 F test n.s. n.s. n.s. n.s. n.s. Table 1: Morphological characteristics of bluemink depending on the contamination of the growth substrate with Zn and Cu Treatment Plant height (cm) Above-ground fresh mass (g) Fresh root mass (g) Number of inflorescences per plant Zn 100 mg kg-1 9.2 ± 1.4 9.8 ± 0.5 1.2 ± 0.3 6.3 ± 1.5 Zn 250 mg kg-1 10.4 ± 2.5 9.5 ± 0.9 1.0 ± 0.3 5.3 ± 1.5 Zn 500 mg kg-1 10.4 ± 1.4 9.5 ± 0.6 1.1 ± 0.2 5.1 ± 1.7 Control 10.6 ± 1.0 10.1 ± 0.9 1.1 ± 0.3 6.0 ± 2.0 F test n.s. n.s. n.s. n.s. Cu 50 mg kg-1 9.5 ± 1.0 10.6 ± 0.8 1.1 ± 0.2 6.0 ± 1.1 Cu 100 mg kg-1 9.9 ± 1.3 10.0 ± 1.6 1.1 ± 0.2 5.4 ± 1.3 Cu 200 mg kg-1 9.2 ± 0.7 8.9 ± 1.3 0.9 ± 0.3 5.3 ± 1.1 Control 10.5 ± 1.1 10.4 ± 1.0 1.1 ± 0.1 6.1 ± 0.9 F test n.s. n.s. n.s. n.s. Results were expressed as mean ± standard deviation (SD); n.s. - non significant Table 2: Morphological characteristics of French marigold depending on the contamination of the growth substrate with Zn and Cu Results were expressed as mean ± standard deviation (SD); n.s. - non significant Acta agriculturae Slovenica, 121/4 – 2025 5 The effectiveness of bluemink ... French marigold (Tagetes patula L.) in removing Zn and Cu from contaminated growing media Treatment Zn content Treatment Cu content Aerial parts Roots Aerial parts Roots Zn 100 mg kg-1 101.7 ± 5.5c 173.8 ± 8.3c Cu 50 mg kg-1 7.8 ± 2.0bc 20.3 ± 4.6b Zn 250 mg kg-1 164.5 ± 21.6b 366.5 ± 20.6b Cu 100 mg kg-1 10.2 ± 2.7b 45.4 ± 4.9a Zn 500 mg kg-1 339.9 ± 19.1a 1457.6 ± 75.9a Cu 200 mg kg-1 16.9 ± 2.8a 51.4 ± 4.1a Control 51.2 ± 8.6d 51.8 ± 4.5d Control 4.7 ± 1.4c 8.3 ± 2.5c F test s. s. F test s. s. LSD0.05 28.8 74.6 LSD0.05 4.3 7.7 Treatment Zn content Treatment Cu content Aerial parts Roots Aerial parts Roots Zn 100 mg kg-1 62.4 ± 2.8c 255.7 ± 6.1c Cu 50 mg kg-1 6.0 ± 1.3b 49.3 ± 3.9c Zn 250 mg kg-1 116.9 ± 6.1b 540.4 ± 13.6b Cu 100 mg kg-1 8.2 ± 1.7b 68.5 ± 4.9b Zn 500 mg kg-1 260.4 ± 14.8a 1946.2 ± 55.6a Cu 200 mg kg-1 17.5 ± 2.3a 87.7 ± 6.8a Control 29.1 ± 1.7d 31.6 ± 7.7d Control 2.9 ± 0.9c 10.3 ± 2.7d F test s. s. F test s. s. LSD0.05 15.6 54.7 LSD0.05 2.6 9.1 Table 3: Zn and Cu levels (mg kg-1 dry mass) in the bluemink grown in contaminated substrates. Results were expressed as mean ± standard deviation (SD); s. - significant; Different letters in the same column indicate statistically significant dif- ferences (p ≤ 0.05) Table 4: Zn and Cu levels (mg kg-1 dry mass) in the French marigold grown in contaminated substrates. Results were expressed as mean ± standard deviation (SD); s. - significant; Different letters in the same column indicate statistically significant dif- ferences (p ≤ 0.05) Treatment BAF TF Treatment BAF TF Zn 100 mg kg-1 1.089 0.585 Cu 50 mg kg-1 0.181 0.384 Zn 250 mg kg-1 0.739 0.449 Cu 100 mg kg-1 0.137 0.225 Zn 500 mg kg-1 0.903 0.233 Cu 200 mg kg-1 0.102 0.199 Control 0.918 0.988 Control 0.271 0.566 Treatment BAF TF Treatment BAF TF Zn 100 mg kg-1 0.785 0.244 Cu 50 mg kg-1 0.207 0.122 Zn 250 mg kg-1 0.689 0.216 Cu 100 mg kg-1 0.142 0.119 Zn 500 mg kg-1 1.047 0.134 Cu 200 mg kg-1 0.123 0.199 Control 0.534 0.921 Control 0.195 0.282 Table 5: Bioaccumulation factor (BAF) and translocation factor (TF) for Zn and Cu determined in the cultivation of bluemink Table 6: Bioaccumulation factor (BAF) and translocation factor (TF) for Zn and Cu determined in the cultivation of French mari- gold tested plants were exposed.Bioaccumulation (BAF) and translocation (TF) factors for Zn and Cu determined in bluemink and French marigold plants are given in Tables 5 and 6. Acta agriculturae Slovenica, 121/4 – 20256 S. MURTIĆ et al. 4 DISCUSSION Despite the high concentrations of Zn and Cu in the growth substrates, and the fact that the accumulation of Zn and Cu in the studied plants generally correlated pos- itively with their concentrations in the growth substrate, no visual symptoms of Zn and Cu toxicity were observed. This suggests that blumink and French marigold belong to Zn- and Cu-tolerant species. The successful growth of these two species in soils enriched with Zn and Cu has also been confirmed in several studies (Mkumbo et al., 2012; Zhou et al., 2017; Fu et al., 2021). From the stand- point of using bluemink and French marigold in land- scape architecture, this data is especially important, par- ticularly in relation to landscaping in regions where the soils are polluted with Zn and Cu. The study’s results also showed that the levels of Zn and Cu in the roots of both plants analysed were up to several times higher than in the above-ground parts. These outcomes are unexpected, particularly because Zn and Cu are essential elements for the plant‘s growth and development. However, high con- centrations of Zn and Cu can disrupt normal metabolic activities, prompting plants to activate mechanisms that restrict the translocation of these metals from the roots to the above-ground parts (Behtash et al., 2022). Hu et al. (2024) reported that plants have evolved various mecha- nisms for this purpose, including heavy metal sequestra- tion in root cell walls or vacuoles, production of heavy metal-binding polypeptides, and the activation of barri- ers that limit the influx of heavy metals from roots to the xylem. The relatively low TF values for Zn and Cu deter- mined in this study (Tables 3 and 4) support the hypothe- sis that bluemink and French marigold possess some spe- cific mechanisms. The TF values for Cu were generally much lower than Zn in both examined plants: bluemink and French marigold, indicating that the mechanisms preventing the transport of Cu from the roots to the aer- ial parts of the plant are more pronounced. The ability of bluemink and French marigold to remove Zn and Cu from contaminated substrates was evaluated by estimating the BAF. The BAF values for Zn in bluemink plants ranged from 0.739 to 1.089. In con- trast, in French marigold plants it varied from 0.534 to 1.047, indicating that both plants possess a relatively high capacity for removing Zn from contaminated sites. Ac- cordingly, both plant species, bluemink and French mari- gold, could be regarded as potential hyperaccumulators of Zn, particularly in the case of their long-term cultiva- tion on contaminated soil. Two other studies have also demonstrated a relatively high capacity of French mari- gold to accumulate Zn from contaminated sites (Mónok et al., 2018; Nair et al., 2019). However, it is important to note that the phytoextraction potential of bluemink and French marigold for Zn primarily relies on the accu- mulation of Zn in the roots, which should be considered when conducting phytoextraction on contaminated soil. In this study, the BAF values for Cu in bluemink plants ranged from 0.102 to 0.271, while in French mari- gold plants it varied from 0.123 to 0.207, depending on the substrate contamination level. In both examined plants, the BAF values for Cu were significantly lower compared to those for Zn. These results support the hy- pothesis that bluemink and French marigold should not be classified as hyperaccumulators for Cu. Similar find- ings for French marigold were observed by Lacerda et al. (2025). On the other hand, several studies have indi- cated that French marigold could be effective in the re- mediation of Cu-contaminated soils (Mónok et al., 2019; Roshanfar et al., 2024). The variations in the ability of French marigold to remove Cu from contaminated soils, as presented in scientific literature, strongly imply that its effectiveness in remediating Cu-polluted soils is con- tingent upon the physico-chemical properties of the soil and other factors that affect Cu phytoavailability (Biswal et al., 2022). In contrast, there is insufficient research on the ability of bluemink to serve as Cu-hyperaccumulator plants; thus, additional studies are required to confirm the low ability of bluemink to remove Cu from the con- taminated substrate noted in this study. 5 CONCLUSIONS This study‘s outcomes imply that both plants ana- lysed, bluemink and French marigold, can tolerate high levels of Cu and Zn in the growing media. No visible Zn and Cu toxicity symptoms were observed in either plant, regardless of the level of substrate contamination. From the Zn and Cu accumulation viewpoint, bluemink and French marigold exhibit a similar behaviour pattern when grown in substrates enriched with Zn and Cu. The levels of Zn and Cu in the roots of both plants analysed were up to several times higher than in the above-ground parts. BAF values determined in this study suggest that both plant species could be regarded as potential hy- peraccumulators of Zn, particularly in the case of their long-term cultivation on contaminated soil. On the other hand, the results from this study revealed that none of the plants investigated exhibited significant phytoextraction potential for Cu. DATA AVAILABILITY STATEMENT The author confirms that all data generated or an- alysed during this study are included in this published article. Acta agriculturae Slovenica, 121/4 – 2025 7 The effectiveness of bluemink ... French marigold (Tagetes patula L.) in removing Zn and Cu from contaminated growing media 6 REFERENCES Alghamdi, S. A., & El-Zohri, M. (2024). Phytoremedia- tion characterization of heavy metals by some native plants at anthropogenic polluted sites in Jeddah, Saudi Arabia. Resources, 13(7), 98. https://doi.org/10.3390/ resources13070098 Al-Sayaydeh, R. S., Al-Hawadi, J. S., Al-Habahbeh, K. A., Al-Nawaiseh, M. B., Albdaiwi, R. N., & Ayad, J. Y. (2022). Phytoremediation potential of selected orna- mental woody species to heavy metal accumulation in response to long-term irrigation with treated waste- water. Water, 14(13), 2086. https://doi.org/10.3390/ w14132086 Angon, P. B., Islam, M. S., Kc, S., Das, A., Anjum, N., Poudel, A., & Suchi, S. A. (2024). Sources, effects and present perspectives of heavy metals contami- nation: Soil, plants and human food chain. Heliyon, 10(7), e28357. https://doi.org/10.1016/j.heliyon.2024. e28357 Balafrej, H., Bogusz, D., Triqui, Z. A., Guedira, A., Bendaou, N., Smouni, A., & Fahr, M. (2020). Zinc hyperaccumulation in plants: A review. Plants (Ba- sel, Switzerland), 9(5), 562. https://doi.org/10.3390/ plants9050562 Behtash, F., Abedini, F., Ahmadi, H., Mosavi, S. B., Aghaee, A., Morshedloo, M. R., & Lorenzo, J. M. (2022). Zinc application mitigates copper toxicity by regulating Cu uptake, activity of antioxidant en- zymes, and improving physiological characteristics in summer squash. Antioxidants (Basel, Switzerland), 11(9), 1688. https://doi.org/10.3390/antiox11091688 Binesh, A., & Venkatachalam, K. (2024). Copper in hu- man health and disease: A comprehensive review. Journal of Biochemical and Molecular Toxicology, 38(11), e70052. https://doi.org/10.1002/jbt.70052 Biswal, B., Singh, S. K., Patra, A., & Mohapatra, K. K. (2022). Evaluation of phytoremediation capability of French marigold (Tagetes patula) and African mari- gold (Tagetes erecta) under heavy metals contami- nated soils. International Journal of Phytoremediation, 24(9), 945-954. https://doi.org/10.1080/15226514.20 21.1985960 Bonanno, G., Vymazal, J., & Cirelli, G. L. (2018). Trans- location, accumulation and bioindication of trace elements in wetland plants. Science of the Total Envi- ronment, 631-632, 252-261. https://doi.org/10.1016/j. scitotenv.2018.03.039 Chen, G., Li, J., Han, H., Du, R., & Wang, X. (2022). Physiological and molecular mechanisms of plant responses to copper stress. International Journal of Molecular Sciences, 23(21), 12950. https://doi. org/10.3390/ijms232112950 Fu, L., Zhang, L., Dong, P., Wang, J., Shi, L., Lian, C., Shen, Z., & Chen, Y. (2021). Remediation of copper-con- taminated soils using Tagetes patula L., earthworms and arbuscular mycorrhizal fungi. International Jour- nal of Phytoremediation, 24(10), 1107–1119. https:// doi.org/10.1080/15226514.2021.2002809 Hu, Y., Wang, J., Yang, Y., Li, S., Wu, Q., Nepovimova, E., Zhang, X., & Kuca, K. (2024). Revolutionizing soil heavy metal remediation: Cutting-edge innovations in plant disposal technology. The Science of the Total Environment, 918, 170577. https://doi.org/10.1016/j. scitotenv.2024.170577 ISO (1998). International Standard ISO 11047: Soil qual- ity - Determination of cadmium, chromium, cobalt, copper, lead, manganese, nickel and zinc - Flame and electrothermal atomic absorption spectrometric meth- ods, International Organization for Standardization: Geneva. Kolesnikov, S., Timoshenko, A., Minnikova, T., Minkina, T., Rajput, V. D., Kazeev, K., Feizi, M., Fedorenko, E., Mandzhieva, S., & Sushkova, S. (2021). Ecotoxicolog- ical assessment of Zn, Cu and Ni based NPs contami- nation in arenosols. SAINS TANAH – Journal of Soil Science and Agroclimatology, 18(2), 143-151. https:// doi.org/10.20961/stjssa.v18i2.56697 Lacerda, L. de C., Swarowsky, A., Menegaes, J. F., Backes, F. A. A. L., & Salazar, R. F. dos S. (2025). Cultiva- tion of Tagetes patula L. in copper contaminated soils. Ciência E Natura, 47, e74452. https://doi. org/10.5902/2179460X74452 Ladislas, S., El‐Mufleh, A., Gerente, C., Chazarenc, F., Andres, Y., & Bechet, B. (2012). Potential of aquatic macrophytes as bioindicators of heavy metal pollu- tion in urban storm water runoff. Water, Air, and Soil Pollution, 223(2), 877-888. https://doi.org/10.1007/ s11270-011-0909-3 Lisjak, M., Špoljarević, M., Agić, D., & Andrić, L. (2009). Practicum-Plant physiology. Faculty of Agriculture in Osijek: Osijek. Mkumbo, S., Mwegoha, W., & Renman, G. (2012). As- sessment of the phytoremediation potential for Pb, Zn and Cu of indigenous plants growing in a gold mining area in Tanzania. International Journal of Environmental Sciences, 2, 2425-2434. https://doi. org/10.6088/ijes.00202030123 Mónok, D., Kardos, L., & Végvári, G. (2018). Effects of heavy metals on early growth of African marigold (Tagetes erecta), French marigold (Tagetes patula) and signet marigold (Tagetes tenuifolia). Proceedings of the International Symposium on Analytical and Environ- mental Problems, 24, 358-362. Mónok, D., Kardos, L., & Végvári, G. (2019). Assessing the phytoremediation potential of marigold species Acta agriculturae Slovenica, 121/4 – 20258 S. MURTIĆ et al. (Tagetes spp.) for various heavy metals using labora- tory test methods. Agrokémia és Talajtan, 68(1), 139- 154. https://doi.org/10.1556/0088.2019.00036 Nair, A. S., Singh, M., & Khosla, B. (2019). Phytoremedi- ation of heavy metals contaminated soil using Tagetes patula. Annals of Biology 35(2), 181-185. Park, J. K., & Oh, K. (2023). Advancements in phytore- mediation research for soil and water resources: Harnessing Plant Power for Environmental Cleanup. Sustainability, 15(18), 13901. https://doi.org/10.3390/ su151813901 Permyakov, E. A. (2021). Metal binding proteins. Ency- clopedia, 1(1), 261-292. https://doi.org/10.3390/ency- clopedia1010024 Rosariastuti, R., Maisyarah, S., Sudadi, Hartati, S., & Pur- wanto. (2019). Remediation of chromium contami- nated soil by Phyto-Bio System (PBS) application. Sains Tanah Journal of Soil Science and Agroclima- tology, 16(1), 90-102. https://doi.org/10.20961/stjssa. v16i1.24932 Roshanfar, M., Farahani, Z., Khanlarian, M., Rashchi, F., & Motesharezadeh, B. (2024). Phytoextraction of copper from copper waste rock by Tagetes sp. Envi- ronmental Science and Pollution Research Internation- al, 31(1), 1026-1032. https://doi.org/10.1007/s11356- 023-31199-9 Sánchez-Castro, I., Molina, L., Prieto-Fernández, M. Á., & Segura, A. (2023). Past, present and future trends in the remediation of heavy-metal contaminated soil - Remediation techniques applied in real soil-con- tamination events. Heliyon, 9(6), e16692. https://doi. org/10.1016/j.heliyon.2023.e16692 Schoofs, H., Schmit, J., & Rink, L. (2024). Zinc toxicity: Understanding the limits. Molecules, 29(13), 3130. https://doi.org/10.3390/molecules29133130 Sharma, J. K., Kumar, N., Singh, N. P., & Santal, A. R. (2023). Phytoremediation technologies and their mechanism for removal of heavy metal from contam- inated soil: An approach for a sustainable environ- ment. Frontiers in Plant Science, 14, 1076876. https:// doi.org/10.3389/fpls.2023.1076876 Yan, A., Wang, Y., Tan, S. N., Mohd Yusof, M. L., Ghosh, S., & Chen, Z. (2020). Phytoremediation: A promis- ing approach for revegetation of heavy metal-pollut- ed land. Frontiers in Plant Science, 11, 359. https://doi. org/10.3389/fpls.2020.00359 Zhou, X., Fu, L., Xia, Y., Zheng, L., Chen, C., Shen, Z., & Chen, Y. (2017). Arbuscular mycorrhizal fungi en- hance the copper tolerance of Tagetes patula through the sorption and barrier mechanisms of intraradi- cal hyphae, Metallomics, 9(7), 936-948. https://doi. org/10.1039/c7mt00072c