Worker studies suggest unique liver carcinogenicity potential of polyvinyl chloride microplastics.

BACKGROUND: Plastic debris pervades our environment. Some breaks down into microplastics (MPs) that can enter and distribute in living organisms causing effects in multiple target organs. MPs have been demonstrated to harm animals through environmental exposure. Laboratory animal studies are still insufficient to evaluate human impact. And while MPs have been found in human tissues, the health effects at environmental exposure levels are unclear. AIM: We reviewed and summarized existing evidence on health effects from occupational exposure to MPs. Additionally, the diverse effects documented for workers were organized by MP type and associated co-contaminants. Evidence of the unique effects of polyvinyl chloride (PVC) on liver was then highlighted. METHODS: We conducted two stepwise online literature reviews of publications focused on the health risks associated with occupational MP exposures. This information was supplemented with findings from animal studies. RESULTS: Our analysis focused on 34 published studies on occupational health effects from MP exposure with half involving exposure to PVC and the other half a variety of other MPs to compare. Liver effects following PVC exposure were reported for workers. While PVC exposure causes liver toxicity and increases the risk of liver cancers, including angiosarcomas and hepatocellular carcinomas, the carcinogenic effects of work-related exposure to other MPs, such as polystyrene and polyethylene, are not well understood. CONCLUSION: The data supporting liver toxicity are strongest for PVC exposure. Overall, the evidence of liver toxicity from occupational exposure to MPs other than PVC is lacking. The PVC worker data summarized here can be useful in assisting clinicians evaluating exposure histories from PVC exposure and designing future cell, animal, and population exposure-effect research studies.

A review of data for quantifying human exposures to micro and nanoplastics and potential health risks.

Plastic debris have been shown to degenerate to particle sizes that can be transported in air, water, and food. Small particles are documented to enter and exit our bodies and translocate to and from some internal organs. Health effects on respiratory, hepatic, immune, and gastrointestinal systems have been reported in humans and other mammals in response to elevated particle or fiber exposures. These health effects differed by plastic type and size, and there was evidence of dose response for a few health endpoints. We conducted a systematic word search and reviewed published literature to identify microplastic and nanoplastic studies that quantified exposure via the ingestion, inhalation, and subcutaneous absorption (not dermal) exposure pathways; identified translocation, internal dose, and associations with health effects and markers related to exposures to specific sizes and types of plastics. We identified the data gaps in relating exposure data to health effects and biomarkers, most notably the lack of characterization of plastic particles and fibers smaller than 10 µm in most media.

Building and Strengthening Infection Control Strategies to Prevent Tuberculosis - Nigeria, 2015.

Tuberculosis (TB) is the leading cause of infectious disease mortality worldwide, accounting for more than 1.5 million deaths in 2014, and is the leading cause of death among persons living with human immunodeficiency virus (HIV) infection (1). Nigeria has the fourth highest annual number of TB cases among countries, with an estimated incidence of 322 per 100,000 population (1), and the second highest prevalence of HIV infection, with 3.4 million infected persons (2). In 2014, 100,000 incident TB cases and 78,000 TB deaths occurred among persons living with HIV infection in Nigeria (1). Nosocomial transmission is a significant source of TB infection in resource-limited settings (3), and persons with HIV infection and health care workers are at increased risk for TB infection because of their routine exposure to patients with TB in health care facilities (3-5). A lack of TB infection control in health care settings has resulted in outbreaks of TB and drug-resistant TB among patients and health care workers, leading to excess morbidity and mortality. In March 2015, in collaboration with the Nigeria Ministry of Health (MoH), CDC implemented a pilot initiative, aimed at increasing health care worker knowledge about TB infection control, assessing infection control measures in health facilities, and developing plans to address identified gaps. The approach resulted in substantial improvements in TB infection control practices at seven selected facilities, and scale-up of these measures across other facilities might lead to a reduction in TB transmission in Nigeria and globally.

Checklist model to improve work practices in small-scale demolition operations with silica dust exposures.

A systematic approach was developed to review, revise and adapt existing exposure control guidance used in developed countries for use in developing countries. One-page employee and multiple-page supervisor guidance sheets were adapted from existing documents using a logic framework and workers were trained to use the information to improve work practices. Interactive, hands-on training was delivered to 26 workers at five small-scale demolition projects in Maputo City, Mozambique, and evaluated. A pre-and-post walkthrough survey used by trained observers documented work practice changes. Worker feedback indicated that the training was effective and useful. Workers acquired knowledge (84% increase, p < 0.01) and applied the work practice guidance. The difference of proportions between use of work practice components before and after the intervention was statistically significant (p < 0.05). Changes in work practices following training included preplanning, use of wet methods and natural ventilation and end-of-task review. Respirable dust measurements indicated a reduction in exposure following training. Consistency in observer ratings and observations support the reliability and validity of the instruments. This approach demonstrated the short-term benefit of training in changing work practices; follow-up is required to determine the long-term impact on changes in work practices, and to evaluate the need for refresher training.