Greater willingness to reduce microplastics consumption in Mexico than in Spain supports the importance of legislation on the use of plastics

Nurse researchers typically provide evidence of content validity for instruments by computing a content validity index (CVI), based on experts' ratings of item relevance. We compared the CVI to alternative indexes and concluded that the widely-used CVI has advantages with regard to ease of computation, understandability, focus on agreement of relevance rather than agreement per se, focus on consensus rather than consistency, and provision of both item and scale information. One weakness is its failure to adjust for chance agreement. We solved this by translating item-level CVIs (I-CVIs) into values of a modified kappa statistic. Our translation suggests that items with an I-CVI of .78 or higher for three or more experts could be considered evidence of good content validity.

Microplastics are ubiquitous environmental contaminants leading to inevitable human exposure. Even so, little is known about the effects of microplastics in human health. Thus, in this work we review the evidence for potential negative effects of microplastics in the human body, focusing on pathways of exposure and toxicity. Exposure may occur by ingestion, inhalation and dermal contact due to the presence of microplastics in products, foodstuff and air. In all biological systems, microplastic exposure may cause particle toxicity, with oxidative stress, inflammatory lesions and increased uptake or translocation. The inability of the immune system to remove synthetic particles may lead to chronic inflammation and increase risk of neoplasia. Furthermore, microplastics may release their constituents, adsorbed contaminants and pathogenic organisms. Nonetheless, knowledge on microplastic toxicity is still limited and largely influenced by exposure concentration, particle properties, adsorbed contaminants, tissues involved and individual susceptibility, requiring further research.