Bioaccumulation and human health risk assessment of trace metals in the freshwater mussel Cristaria plicata in Dongting Lake, China

Trace metal contamination in water and bioaccumulation in aquatic organisms are human health risks of increasing concern. However, the bioaccumulation of trace metals in the organs of the mussel Cristaria plicata in Dongting Lake, China and the human health risks of mussel consumption are largely unknown. We investigated the concentrations of 15 trace metals and metalloids in surface water, sediments, and C. plicata organs(foot, gill, mantle, and visceral mass) and quantified the bioaccumulation and human health risk of these trace metals in specimens collected from Dongting Lake. The concentrations of most metals in surface water exceeded previously published background values. In contrast, the concentrations of most metals in sediments showed a decreasing trend. Overall, the metal concentrations in the gill and visceral masses of C. plicata were higher than those in the foot and mantle, and higher bioaccumulation capacities were observed for essential metals than for nonessential metals. The mean concentrations of the trace elements Zn, Pb, Cd, As, Cu, and Cr in C. plicata foot samples were lower than the threshold values established by international and Chinese organizations. The estimated daily intake(EDI) values of the essential metal Mn in C. plicata foot was higher than the recommended tolerable daily intake(TDI) values for juveniles. Only Mn for juveniles and As for both juveniles and adults may pose noncarcinogenic health risks through foot consumption. The hazard index(HI) values for adults and juveniles were higher than 1, suggesting significant risks of noncarcinogenic effects to humans by exposure to multiple metals.

A wireless, implantable optoelectrochemical probe for optogenetic stimulation and dopamine detection

Physical and chemical technologies have been continuously progressing advances in neuroscience research.The development of research tools for closed-loop control and monitoring neural activities in behaving animals is highly desirable.In this paper,we introduce a wirelessly operated,miniaturized microprobe system for optical interrogation and neurochemical sensing in the deep brain.Via epitaxial liftoff and transfer printing,microscale light-emitting diodes(micro-LEDs)as light sources and poly(3,4-ethylenedioxythiophene)polystyrene sulfonate(PEDOT:PSS)-coated diamond films as electrochemical sensors are vertically assembled to form implantable optoelectrochemical probes for real-time optogenetic stimulation and dopamine detection capabilities.A customized,lightweight circuit module is employed for untethered,remote signal control,and data acquisition.After the probe is injected into the ventral tegmental area(VTA)of freely behaving mice,in vivo experiments clearly demonstrate the utilities of the multifunctional optoelectrochemical microprobe system for optogenetic interference of place preferences and detection of dopamine release.The presented options for material and device integrations provide a practical route to simultaneous optical control and electrochemical sensing of complex nervous systems.