17α-Ethinylestradiol (EE2), a synthetic estrogen widely used in pharmaceuticals, is a potent endocrine disruptor capable of causing adverse effects even at trace concentrations. To enable its sensitive determination, we developed a carbon paste electrode modified with activated biochar derived from green coconut mesocarp and functionalized with Au@Pd nanoparticles. The activated biochar presented a porous, high-surface area framework, while the bimetallic nanoparticles enhanced conductivity and electrocatalytic activity. The resulting sensor exhibited excellent linearity in the range of 0.05-5.0μM (R2=0.9993), achieving a detection limit of 2.53nM and a quantification limit of 8.43nM, nearly three orders of magnitude lower than those obtained by a reference chromatographic method (LOD: 5.14μM, LOQ: 17.14μM). Intra-day (RSD=5.77%) and inter-day (RSD=8.14%) reproducibility met accepted analytical criteria. Selectivity studies revealed significant interference only from 17β-estradiol and ascorbic acid, yielding relative errors of +165.38% and +72.63%, respectively. By contrast, urea, NaCl, and caffeine showed negligible effects (-10.38% to +6.03%), demonstrating the robustness of the sensor in biological and saline matrices. The applicability of the method was confirmed by quantifying EE2 in a commercial contraceptive (declared: 6.746μM; found: 6.706μM; recovery: 99.41%) and in real and simulated matrices, including groundwater, tap water, synthetic urine, saline solution, and artificial breast milk. These results highlight the potential of this biochar-based nanocomposite electrode as a low-cost, sustainable, and efficient platform for decentralized monitoring of endocrine-disrupting contaminants.

The Tubarão River-estuarine system (TRES), located in the South Atlantic, Brazil, is essential for water supply, agriculture, fisheries, and industrial activities. It has historically been affected by coal extraction, urbanisation, and industrial discharges, activities that generate significant impacts on ecosystem health, such as decreased water quality, habitat degradation, and potential bioaccumulation of toxic compounds in aquatic organisms. Nineteen sediment samples were collected along the TRES to assess contamination levels and evaluate the sources and spatial distribution of pollution. The study encompassed both aliphatic hydrocarbons (AHs) and polycyclic aromatic hydrocarbons (PAHs). Total AH concentrations ranged from 3.86 to 69.4μgg-1 (mean: 25.7±20.7μgg-1), with ΣC10-C40n-alkanes accounting for 0.34-12.0μgg-1 (mean: 4.65±4.07μgg-1). PAH levels were between 6.42 and 6440.2ngg-1 (mean: 1370.7±1654.6ngg-1 for Σ27PAHs, excluding retene and perylene) and 3.47 to 1540.8ngg-1 (mean: 323.4±385.5ngg-1) for Σ16PAHs. The TRES is strongly influenced by anthropogenic hydrocarbons, with the most prominent contamination observed in the upper reaches of the river and the Rocinha River tributary. The middle section of the system is moderately affected, likely due to dilution by tributary inputs, while the lower reaches experience consistent pollution from urban and industrial activities. Contamination pattern is potentially influenced by fine coal particles and sorbent nanoparticles derived from mining and other coal-related activities. In this context, these particles may also influence source apportionment analyses, which revealed mixed petrogenic- and pyrogenic-like signatures, consistent with the geochemical characteristics of coal-derived PAHs in coal-influenced systems. These data are crucial for monitoring long-term pollution trends, as environmental conditions and contamination levels typically change gradually, offering valuable insights for future assessments and regional policy development.

Water-soluble polymers have exceptional properties and are therefore used in many applications. Many of these products end up down the drain; therefore biodegradability, especially in wastewater treatment plants, is essential to prevent accumulation in the environment. This study examined recombinant hydrolases PahZ1KT-1 and PahZ2KT-1 from Sphingomonas sp. KT-1 and PahZ1KP-2 from Pedobacter sp. KP-2 for their role in biodegrading water-soluble poly(aspartic acid) (tPAA). Analysis by a turbidity assay and Gel Permeation Chromatography (GPC) revealed highest activity of PahZ1KT-1 and PahZ1KP-2 at pH 8 and 40°C on tPAA, whereas PahZ2KT-1 showed no activity on the polymer but yet on its oligopeptides with highest values at pH 7 and 55°C. GPC analysis revealed that PahZ1KT-1 and PahZ1KP-2 hydrolyzed tPAA (MN>17,000Da) into oligopeptides (>500Da), while PahZ2KT-1 further degraded them to α-di(l-aspartic acid) and l-aspartic acid. Combined, these enzymes synergistically decomposed tPAA completely into l-aspartic acid within 24h. Supplementation of hydrolases into standardized biodegradation test improved biodegradation (54%) of tPAA after 28d. Supplementing PahZ1KT-1 or PahZ1KP-2 alone achieved 52% and 54% tPAA biodegradation, respectively. Preincubating tPAA with hydrolases boosted degradation to 71% in 28d. These findings highlight enzymes' crucial role in breaking down macromolecules into lower molecular weight species for effective tPAA biodegradation.

Temporal trends of bioavailable PCB water concentrations from a long running mussel biomonitoring program (1998-2023) in the Detroit River, Ontario, Canada. Bioavailable sum PCB10 concentrations exhibited long term declines at two biomonitoring locations but such declines were influenced by changes in water levels and showed different responses among individual congeners. Temporal declines in PCBs were highest rising water levels, PCBs reverted to an increasing trend for all congeners at the upstream biomonitoring location. At the midstream location, only PCBs 28+31 and 52 changed their temporal trajectories, while other PCBs slowed their decline relative to the constant water level regime. A deep neural network (DNN) model was trained to the data. The parsimony optimized model identified sediment PCB concentrations, chemical KOW, mean annual water level and year as the most important predictors of PCB water concentrations and explained more than double the variation compared to a multiple regression model. Overall, both empirical and modeled results show that hydrological fluctuations significantly affected bioavailable PCB concentrations and their temporal trends in this system. As water levels continue to decline in the Detroit River, PCBs are expected to resume their previous decreasing trend in the coming years.

This study investigates the remarkable potential of living Mixed Indigenous Microalgae (MIMA) for mercury bioremediation in aquatic environments at environmentally relevant concentrations (10-100μg/L). Our research demonstrates high mercury removal efficiency (89-94%) across all tested concentrations, with rapid kinetics achieving equilibrium within just 2min of contact time. The maximum biosorption capacity reached 0.10mg/g at 100μg/L initial concentration. Notably, MIMA maintained both viability and removal efficiency when exposed to Hg for 3 days without any addition of nutrients suggesting resilience under nutrient-limited conditions. Comprehensive isotherm analysis revealed the Dubinin-Radushkevich model provided the best fit (R2=0.998), indicating physical adsorption as the predominant mechanism, as the calculated mean free energy (E=5.00kJ/mol) falls within the 1-8kJ/mol range characteristic of physical adsorption. Kinetic studies showed superior correlation with the pseudo-second-order model (R2>0.996), with rate constants decreasing systematically from 767.5 to 216.0g/mg·min as concentration increased, suggesting secondary chemical interactions may also contribute to the overall mechanism. Advanced characterization revealed significant surface modifications, with Scanning Electron Microscopy (SEM) showing increased surface roughness, Fourier Transform Infrared Spectroscopy (FTIR) indicating involvement of hydroxyl, protein, and carbohydrate functional groups, and X-ray Photoelectron Spectroscopy (XPS) confirming Hg(II) binding to oxygen-containing moieties with distinctive Hg 4f peaks at 101.78 and 105.8eV. Optical microscopy revealed the formation of sudden spherical-shell boundaries around individual cells providing visual evidence of an immediate physico-chemical response at the cell-mercury interface, correlating with the observed rapid kinetics. This research addresses critical knowledge gaps regarding living microalgae-mediated mercury removal and demonstrates MIMA's potential as a sustainable, efficient solution for mercury contamination in aquatic ecosystems, maintaining viability even under nutrient-limited conditions while effectively reducing mercury concentrations to near guideline values at the lowest initial level (10μg/L).