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The bacteria of shellfish bioaccumulate mainly in the gill and digestive gland tissues, which can affect shellfish health status and disease susceptibility under stressful conditions or environmental effects. Ruditapes philippinarum is a filter-feeding shellfish with both ecological and economic significance, and it is classified as a Mollusca (phylum), Bivalvia (class), Veneridae (family), and Ruditapes (genus). In this study, 16S high-throughput sequencing was used to explore the microbiomics of digestive glands and gills of R. philippinarum under temporary rearing without feeding (including the purification process) in different water environments (natural vs. artificial seawater) from 0–7 days. The results revealed that the digestive glands and gills of R. philippinarum had their own unique bacterial community structures. Tissue microorganisms under the overlap of different water environments and starvation factors showed different dynamic effects within 0–7 days. The sand spitting and purification steps (posttransport rehydration stage of 24 hours) effectively reduced microorganism abundance. There were different biomarkers in the prerearing and postrearing periods, and R. philippinarum may be more susceptible to the enrichment of opportunistic pathogenic bacteria during the postrearing period in artificial seawater.

Pyrethroids are common contaminants in water bodies. In this study, an efficient mussel shell-based adsorbent was prepared, the effects of factors (calcination temperature, calcination time, and sieved particle size) on the pyrethroid adsorption capacity from calcined shell powder were investigated via Box–Behnken design, and the prediction results of the model were verified. By characterizing (scanning electron microscopy, X-ray diffraction, Fourier infrared spectroscopy, and Brunauer–Emmett–Teller measurements) the adsorbent before and after the optimized preparation process, the results showed that calcined shell powder had a loose and porous structure, and the main component of the shell powder under optimized condition was calcium oxide. The adsorption mechanism was also investigated, and the analysis of adsorption data showed that the Langmuir, pseudo second-order, and intra-particle diffusion models were more suitable for describing the adsorption process. The adsorbent had good adsorption potential for pyrethroids, the adsorption capacity of the two pesticides was 1.05 and 1.79 mg/g, and the removal efficiency was over 40 and 70% at the maximum initial concentration, respectively.