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.

We piloted a methodology for collecting and interpreting root cause—or environmental deficiency (ED)—information from Legionnaires’ disease (LD) outbreak investigation reports. The methodology included a classification framework to assess common failures observed in the implementation of water management programs (WMPs). We reviewed reports from fourteen CDC-led investigations between 1 January 2015 and 21 June 2019 to identify EDs associated with outbreaks of LD. We developed an abstraction guide to standardize data collection from outbreak reports and define relevant parameters. We categorized each ED according to three criteria: ED type, WMP-deficiency type, and source of deficiency. We calculated the prevalence of EDs among facilities and explored differences between facilities with and without WMPs. A majority of EDs identified (81%) were classified as process failures. Facilities with WMPs (n = 8) had lower prevalence of EDs attributed to plumbed devices (9.1%) and infrastructure design (0%) than facilities without WMPs (n = 6; 33.3% and 24.2%, respectively). About three quarters (72%) of LD cases and 81% of the fatalities in our sample originated at facilities without a WMP. This report highlights the importance of WMPs in preventing and mitigating outbreaks of LD. Building water system process management is a primary obstacle toward limiting the root causes of LD outbreaks. Greater emphasis on the documentation, verification, validation, and continuous program review steps will be important in maximizing the effectiveness of WMPs.

In 2009 the Haitian Directorate of Potable Water and Sanitation (DINEPA) identified an inadequately trained and under-staffed rural workforce as one of their main institutional challenges. Plans to address this challenge were impacted by the devastating earthquake of January 12, 2010 and the cholera outbreak of October 2010, both of which further complicated Haiti's already poor water and sanitation conditions. Recognizing the importance of DINEPA's institutional priorities, donor and technical assistance groups provided needed support to improve the country's conditions and build the rural water and sanitation workforce. This report describes how DINEPA and the US Centers for Disease Control and Prevention (CDC) collaborated to design and implement a training program for 264 potable water and sanitation technicians for rural areas. The paper also describes the initial field activities of the newly trained technicians and the immediate impact of their work in the rural water, sanitation and hygiene sector.

Despite the development of the Model Aquatic Health Code (MAHC), U.S. public health departments and aquatics agencies face obstacles in incorporating this guidance into their pool codes. A cross comparison of five state pool codes with the MAHC was conducted to quantify MAHC incorporation into these state codes. The proportion of MAHC code agreement with state codes in this study had a range of 14%–86%. Only 2% of all the MAHC codes available were present in all five state codes, conversely, 12% of the MAHC codes were not found in any state. These differences in code agreement highlight the challenge of measuring MAHC effectiveness at the national level. To improve aquatic safety at a national level, a potential solution is development and use of common core elements in state and local pool codes. Once there is a basis for code comparisons across states, public health programs can investigate whether core MAHC codes result in reduced waterborne illness outbreaks, drowning incidents, injuries from pool chemicals, health outcomes from exposure to disinfection by-products, and swimming-related emergency department visits.