Following the physiological complementary/parallel Celis-Plá et al., by inhibiting extracellular signal regulated kinases (ERK), c-Jun N-terminal kinases (JNK), and cytokinin specific binding protein (p38), we assessed the role of the mitogen-activated protein kinases (MAPK) pathway in detoxification responses mediated by chronic copper (10 µM) in U. compressa. Parameters were taken at 6, 24, and 48 h, and 6 days (d). H₂O₂ and lipid peroxidation under copper and inhibition of ERK, JNK, or p38 alone increased but recovered by the sixth day. By blocking two or more MAPKs under copper, H₂O₂ and lipid peroxidation decayed even below controls. Inhibition of more than one MAPK (at 6 d) caused a decrease in total glutathione (reduced glutathione (GSH) + oxidised glutathione (GSSG)) and ascorbate (reduced ascorbate (ASC) + dehydroascorbate (DHA)), although in the latter it did not occur when the whole MAPK was blocked. Catalase (CAT), superoxide dismutase (SOD), thioredoxin (TRX) ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), and glutathione synthase (GS), were downregulated when blocking more than one MAPK pathway. When one MAPK pathway was blocked under copper, a recovery and even enhancement of detoxification mechanisms was observed, likely due to crosstalk within the MAPKs and/or other signalling processes. In contrast, when more than one MAPK pathway were blocked under copper, impairment of detoxification defences occurred, demonstrating that MAPKs were key signalling mechanisms for detoxification in macroalgae.

There is currently no information regarding the role that whole mitogen activated protein kinase (MAPK) pathways play in counteracting environmental stress in photosynthetic organisms. To address this gap, we exposed Ulva compressa to chronic levels of copper (10 µM) specific inhibitors of Extracellular Signal Regulated Kinases (ERK), c-Jun N-terminal Kinases (JNK), and Cytokinin Specific Binding Protein (p38) MAPKs alone or in combination. Intracellular copper accumulation and photosynthetic activity (in vivo chlorophyll a fluorescence) were measured after 6 h, 24 h, 48 h, and 6 days of exposure. By day 6, when one (except JNK) or more of the MAPK pathways were inhibited under copper stress, there was a decrease in copper accumulation compared with algae exposed to copper alone. When at least two MAPKs were blocked, there was a decrease in photosynthetic activity expressed in lower productivity (ETR_max), efficiency (α_ETR), and saturation of irradiance (EkETR), accompanied by higher non-photochemical quenching (NPQ_max), compared to both the control and copper-only treatments. In terms of accumulation, once the MAPK pathways were partially or completely blocked under copper, there was crosstalk between these and other signaling mechanisms to enhance metal extrusion/exclusion from cells. Crosstalk occurred among MAPK pathways to maintain photosynthesis homeostasis, demonstrating the importance of the signaling pathways for physiological performance. This study is complemented by a parallel/complementary article Rodríguez-Rojas et al. on the role of MAPKs in copper-detoxification.

In Chile, there are several abandoned mine tailing impoundments near population centers that need to be remediated. In this study, the ability of Oxalis gigantea, Cistanthe grandiflora, and Puya berteroniana to remove Zn, Ni, and Cr from mine tailings was evaluated. The plants’ removal efficiency, bioconcentration, and translocation factors regarding these metals were determined to assess the ability of certain endemic species from Northern and Central Chile to extract or stabilize metals. After a period of seven months, the chemical analysis of plants and tailings, together with the statistical treatment of data, indicated the inability of all the species to translocate Ni, Cr, or Zn with a translocation factor lower than one. The results showed the stabilizing character of Oxalis gigantea, Puya berteroniana, and Cistanthe grandiflora for Zn, with a bioconcentration factor close to 1.2 in all cases, and the same ability of the latter two species for Cr, with a bioconcentration factor of 1.5 in the case of Cistanthe grandiflora and 1.7 for Puya berteroniana. Finally, a removal efficiency of 9.3% was obtained with Cistanthe grandiflora for Cr and 15% for Ni; values lower than 6.4% were obtained for Zn in all cases. Improvements in the process should be sought to enhance the performance of these species for the accumulation of the target metals.

The analysis of Cu distribution in pre-treated mine tailings after electrodialytic remediation was carried out by using two methods of sequential extraction. The initial content of copper in the tailings was 1109 mg Cu/kg of dry tailing, where close to 40% of the sample in weight corresponded to a soluble fraction. The tailing was treated with a leaching solution for 24 h. Three different solutions were tested: H₂SO₄ + HNO₃ with pH = 1.9; H₂SO₄ + HNO₃ with pH = 4.2; and NH₄Cl 0.8 mol/L with pH = 5.5. After that, electrodialytic remediation experiments were carried out using an electric field of 2.7 V/cm for 15 days. The best performance for the complete cell was obtained with H₂SO₄ + HNO₃ solutions, with a copper removal efficiency in the range of 62% to 67% and a current efficiency between 6% and 9%. The results of the remaining copper concentration between anode and cathode, from both procedures of sequential extraction, showed similar trends. The differences were mainly attributed to the use of different extractant solutions and extraction times. Soluble and exchangeable fractions were easily removed, with efficiencies higher than 80%. The lowest copper removal efficiency was obtained with NH₄Cl 0.8 mol/L.

The increasing release of Cu(II) into aquatic environments has intensified the demand for efficient and selective removal strategies. Although adsorption is widely applied for Cu(II) removal, its performance is often constrained by limited accessibility and low selectivity of active sites. In this study, a hybrid ion-imprinted polymer was synthesised via a single-step grafting–imprinting–polymerisation (SGPI) strategy, enabling the formation of a surface-oriented imprinted polymer layer on a functionalised graphene oxide support (GO/MPS). 4-vinylpyridine (4VP) was employed as the functional monomer to promote specific Cu–N coordination and facilitate binding-site formation. The resulting GO/MPS@IIPs-Cu(II) achieved an adsorption capacity (Qmax) of 256 mg g⁻¹, together with faster adsorption kinetics relative to bulk IIPs-Cu(II). The material also demonstrated improved selectivity for Cu over competing ions (Co, Fe, and Ba), as well as satisfactory reusability, maintaining extraction efficiencies above 98% after eight adsorption–desorption cycles. These findings demonstrate that the SGPI strategy enables a more organised distribution of imprinted binding sites, thereby improving their accessibility and promoting a synergistic combination of high adsorption capacity, rapid kinetics, selectivity, and reusability. This approach establishes a robust platform for the development of advanced hybrid ion-imprinted polymers for the selective removal of metal ions.

Although Quintero-Puchuncaví Bay, Chile, is a coastal area historically known to be subject to multiple industrial pressures, few studies have focused on the associated risks to marine ecosystems and, through edible species, to human health. We studied concentrations of Cd, Cr, Cu, Mn, Pb, V, Zn, and Hg in marine species and sediments from Quintero-Puchuncaví Bay and a reference site. Results were compared with seafood safety guidelines, and target hazard quotients (THQs) were evaluated. Sediments and biota from the impacted area generally exhibited higher metal concentrations. Zinc (Zn) and copper (Cu) levels were the highest across all species, particularly in crustaceans, reflecting both physiological requirements and anthropogenic inputs. Cadmium (Cd) concentrations were higher in pelagic species from the impacted bay, but no differences were found in sediments or benthic species, suggesting the influence of upwelling conditions. Comparison with seafood safety guidelines revealed that Cd and Pb concentrations exceeded permissible limits in crabs, fish, and mussel species, and THQ ≥ 1 values were found for Cd concentrations in benthic species from the impacted bay, highlighting potential risks to consumers. The absence of permissible thresholds for certain environmentally relevant metals in Chilean regulations underscores the need to align with international standards, certainly to protect coastal ecosystems and human health.