Scientific studies of microplastics have expanded since 2015, propelling the topic to the forefront of scientific inquiry. Microplastics are ubiquitous in the environment and pose a potential risk to human health. The purpose of this review is to organize microplastics literature into areas of scientific research, summarize the state of the literature and identify the current data gaps in knowledge to promote a better understanding of human exposure to microplastics and their potential health effects. We searched for published literature from eight databases. Our search focused on three categories: (1) microplastics in the environment, (2) adsorption and absorption of chemicals to microplastics, and (3) human exposure to microplastics in the environment. We screened all abstracts to select articles that focused on microplastics. We then screened the remaining articles using criteria outlined in a questionnaire to identify and assign articles to the three scoping review categories. After screening abstracts, we selected 1186 articles (19%) to thoroughly assess their appropriateness for inclusion in the final review. Of the 1186 articles, 903 (76.1%) belonged to the environmental category, 268 (22.6%) to the adsorption and absorption category, and 16 (1.3%) to the human exposure category. Water was the most frequently studied environmental medium (440 articles). Our assessment resulted in 572 articles selected for the final review. Of the 572 publications, 268 (48.2%) included a geographic component and 110 (19.2%) were the product of literature reviews. We also show that relatively few publications have investigated human health effects associated with exposures to microplastics.

Natural and anthropogenic disasters are associated with air quality concerns due to the potential redistribution of pollutants in the environment. Our objective was to conduct a spatiotemporal analysis of air concentrations of benzene, toluene, ethylbenzne, and xylene (BTEX) and criteria air pollutants in North Carolina during and after Hurricane Florence. Three sampling campaigns were carried out immediately after the storm (September 2018) and at four-month intervals. BTEX were measured along major roads. Concurrent criteria air pollutant concentrations were predicted from modeling. Correlation between air pollutants and possible point sources was conducted using spatial regression. Exceedances of ambient air criteria were observed for benzene (in all sampling periods) and PM2.5 (mostly immediately after Florence). For both, there was an association between higher concentrations and fueling stations, particularly immediately after Florence. For other pollutants, concentrations were generally below levels of regulatory concern. Through characterization of air quality under both disaster and “normal” conditions, this study demonstrates spatial and temporal variation in air pollutants. We found that only benzene and PM2.5 were present at levels of potential concern, and there were localized increases immediately after the hurricane. These substances warrant particular attention in future disaster response research (DR2) investigations.

Unprecedented inland precipitation and catastrophic flooding associated with Hurricane Harvey potentially redistributed contaminants from industrial sites and transportation infrastructure to recreational areas that make up networks of green infrastructure, creeks, and waterways used for flood control throughout the Greater Houston Area. Sediment samples were collected in parks located near the Buffalo Bayou watershed 1 week after Hurricane Harvey made landfall and again 7 weeks later. Total concentrations of the U.S. Environmental Protection Agency's (EPA's) 16 priority polycyclic aromatic hydrocarbons (PAHs) were measured in each sample at both time points. Diagnostic ratios were calculated to improve understanding of potential sources of PAHs after flooding. Diagnostic ratios suggest vehicular traffic to be a potential source for PAHs in parks. Although the concentrations of PAHs in all samples were below EPA actionable levels, given that no background values were available for comparison, it is difficult to quantify the impact flooding from Hurricane Harvey had on PAH concentrations in Houston parks. However, given the high frequency of flooding in Houston, and the concentration of industrial facilities and transportation infrastructure adjacent to recreation areas, these data demonstrate that PAHs were still present after unprecedented flooding. This study may also serve as a baseline for future efforts to understand the environmental health impacts of disasters.

Human exposure to micro- and nanoplastics (MNPs) in the environment and their potential health effects are of growing public interest. Regarding water, that interest grows because multiple studies found MNPs in different matrices including tap and bottled water. We intended to (i) understand how MNPs enter freshwater systems and drinkable water, (ii) assess the evidence of human exposure to MNPs in water, and (iii) identify data gaps to support the determination of potential health effects. We searched the literature and selected studies via rigorous inclusion criteria, analyzed the data assessing the reliability of findings, and identified data gaps associated with human exposure to MNPs in water. The lack of standard sampling and analytical methods for testing MNPs in water constitutes a barrier to make accurate comparisons. The diverse analytical methods to fully characterize MNPs led to different findings in samples of similar matrices. Current drinking and wastewater treatment systems are not designed to remove MNPs. However, efforts to enhance the precision and accuracy of MNPs’ characterization and their removal by treatment systems are promising. Therefore, addressing data gaps could produce reliable data for conducting exposure and risk assessments, protect our communities, and control the mobility of MNPs to minimize exposures.

In the last few years, microplastics research has exploded, with the field exploring new procedures and techniques that focus on a variety of scientific and policy issues. As there are not standardized definitions for many terms in the field, including the term microplastic itself, researchers utilize the same labels to describe different aspects of microplastic pollution. Here we provide a visual tool, called a Hub for Interactive Literature (HIL), to assist researchers in identifying and targeting specific literature. Currently, there are four Hubs for Interactive Learning (HILs) corresponding to previously published reviews, including a scoping review of microplastics literature as well as three reviews examining the human exposure and health effects of microplastics, the unique liver carcinogenicity of polyvinyl chloride (PVC) microplastics, and micro and nanoplastics found in the air. The HILs incorporate all of the literature used to produce the corresponding reviews. A couple of advantages that HILs provide in their capacity as a supportive instrument are the filtering options and easily accessed original references. This tool can be leveraged by researchers to rapidly review microplastics research and isolate specific subtopics of interest to develop new conclusions and quickly identify data gaps. We give an in-depth look at the HIL corresponding to a scoping review of microplastics literature to exhibit the novel functionality and advantages of this exciting tool. We demonstrate a novel world map of the literature to show that microplastics are a global scientific and public health issue. The map offers the additional functionality of filtering the references by country. We also provide a brief description of the current HILs to show the flexibility and personalization available when using this method.