Microplastics in remote coral reef environments of the Xisha Islands in the South China Sea: Source, accumulation and potential risk.

Microplastics (MPs) are of great concern to coral health, particularly enhanced biotoxicity of small microplastics (< 100 µm) (SMPs). However, their fate and harm to remote coral reef ecosystems remain poorly elucidated. This work systematically investigated the distributions and features of MPs and SMPs in sediments from 13 islands/reefs of the Xisha Islands, the South China Sea for comprehensively deciphering their accumulation, sources and risk to coral reef ecosystems. The results show that both MPs (average, 682 items/kg) and SMPs (average, 375 items/kg) exhibit heterogeneous distributions, with accumulation within atolls and dispersion across fringing islands, which controlled by human activities and hydrodynamic conditions. Cluster analysis for the first time reveals a pronounced difference in their compositions between the southern and northern Xisha Islands and resultant distinct sources, i.e., MPs in the north part were leaked mainly from local domestic sewage and fishing waste, while in the south part were probably derived from industrial effluents from adjacent countries. Our ecological risk assessment suggests that the ecosystem within the Yongle Atoll is exposed to a high-risk of MPs pollution. The novel results and proposed framework facilitate to effectively manage and control MPs and accordingly preserve a fragile biosphere in remote coral reefs.

[Pathogenesis of Psoriatic Pruritus].

Pruritus is a common symptom of most primary skin diseases and some systemic diseases. Despite the high incidence of pruritus in patients with psoriasis,the specific pathogenesis is complex and unclear. The occurrence and development of skin pruritus in psoriasis patients involve the joint participation of nervous,immune,endocrine,and vascular systems.This article reviews the mediators related to the pathogenesis of pruritus in psoriasis,aiming to improve the understanding of itching symptoms and the treatment of pruritus.