Toxics

Accurate assessment of dietary exposure to cadmium in mushrooms is crucial for food safety. The inherent limitation lies in relying solely on total cadmium content, failing to reflect its actual bioaccessibility. This study integrated speciation analysis and bioaccessibility to provide a comprehensive risk evaluation. The results showed that cadmium primarily existed in the residual state across Lentinus edodes, Morchella esculenta, Cordyceps militaris, Lyophyllum decastes, Agaricus blazei, and Stropharia rugosoannulata, indicating that a significant portion of the cadmium is tightly bound within insoluble cellular structures, rendering it relatively inert and low mobility. Among them, A. blazei exhibited the highest total cadmium (3.84 mg/kg) and contained detectable acid-soluble cadmium. However, the in vitro bioaccessibility of A. blazei was low (~6%), and no cadmium was detected in the other five mushrooms after biomimetic digestion, reflecting “high content, low release” characteristics. For A. blazei, digestion significantly increased soluble polysaccharides, suggesting that the substantial release of polysaccharides in the gastrointestinal environment not only contributes to their bioactive functions but may also inhibit the dissolution and absorption of cadmium through mechanisms such as adsorption and complexation. Concludingly, this study underscores the necessity of integrating bioaccessibility data for the accurate safety assessment of cadmium in mushrooms.

Aquaculture faces environmental challenges from sediment contamination by potentially toxic elements. This study investigated how aquaculture patterns and seasons jointly affect the distribution and ecological risks of these potentially toxic elements in sediments. By analyzing and comparing sediment samples from different aquaculture systems across seasons, we found that Mn (mean = 435.42 mg/kg) was the most abundant, followed by Zn (mean = 172.69 mg/kg), Cr (mean = 106.79 mg/kg), and Cu (mean = 63.44 mg/kg). Aquaculture patterns were the primary factor determining the composition of potentially toxic elements, followed by season. Fish farming tended to promote their accumulation in sediments, whereas the rice–crayfish co-culture model effectively reduced the enrichment of potentially toxic elements and their associated ecological risks. Therefore, optimizing aquaculture practices proves more effective in controlling these risks than managing seasonal variations. Moreover, total phosphorus was identified as a key driver of potentially toxic element accumulation in sediments. The results from the rice–crayfish co-culture system indicate that enhanced phosphorus management is crucial for mitigating such risks. Accordingly, it is necessary to develop systematic monitoring and integrated remediation strategies focused on priority metals and their main drivers.

This study aims to develop a cost-effective and scalable modification strategy for valorizing lignin-rich biogas residue (BR) into high-performance adsorbents for anionic dye removal. To screen the optimal modification pathway, three distinct reagents, L-cysteine-based amino acid ionic liquids (AAILs, as green alternatives), conventional hydrochloric acid (HCl) and sodium hydroxide (NaOH, as traditional modification reagents), were compared in modifying non-carbonized BR for Congo Red (CR) adsorption. Comprehensive characterizations and adsorption tests revealed that each modifier exerted unique effects: NaOH only caused mild surface etching with limited performance improvement; AAILs achieved moderate adsorption capacity via a green, mild route; while HCl modification (BR-HCl) stood out with the most superior performance through a “selective dissolution-pore reconstruction” mechanism. Notably, despite a modest specific surface area increase to 12.05 m²/g, BR-HCl’s high CR adsorption capacity (120.21 mg/g at 45 °C) originated from the synergy of chemical bonding and enhanced electrostatic attraction—its isoelectric point (pH_PZC ≈ 9.02) was significantly higher than that of AAIL- and NaOH-modified samples, enabling strong affinity for anionic CR across a wide pH range. BR-HCl attained over 99% CR removal at a dosage of 0.4 g/L, fitted well with Langmuir isotherm and pseudo-second-order kinetic models (confirming monolayer chemisorption), and retained 82% of its initial capacity after five regeneration cycles. These results demonstrate that while AAILs show promise as green modifiers and NaOH serves as a baseline, the facile, low-cost HCl modification offers the most pragmatic pathway to unlock BR’s potential for sustainable wastewater treatment.