Rivers may be delivering far more microplastic pollution to the oceans than previously realized, with developing countries accounting for nearly all of the global flow, according to a new study. The worldwide analysis also finds that heavy rainfall can unleash surges of microplastics into rivers – a climate-sensitive pollution threat that could intensify as extreme weather becomes more common. Microplastics have become a pervasive and long-lasting form of pollution, with recognized threats to ecosystems, water quality, and human health. Each year, tens of millions of metric tons of microplastics enter the environment, and much of that material ultimately reaches the oceans. Rivers are a major pathway for transporting these particles from inland regions to coastal waters. However, estimates of global riverine microplastic pollution vary widely because of inconsistent sampling methods and limited understanding of how rainfall and runoff affect their transport. Here, Hehao Qin and colleagues developed a new framework to produce more reliable, high-resolution estimates of microplastic concentrations and export from rivers. According to the authors, their approach harmonizes differences in particle size and sampling methods, while using machine learning to account for both human activity and natural processes. It also tracks how rainfall can either increase or dilute microplastic concentrations. Using this approach, Qin et al. estimate that rivers worldwide delivered roughly 263,000 tons of microplastics to the ocean in 2022, with 96% originating from the Global South – Southeast and East Asia alone contribute to more than half of this total. Plastic use, poorly managed waste, and human development were the strongest drivers of geographic differences in microplastic concentrations, while weather and seasonal conditions influenced short-term fluctuations. The findings show that extreme rainfall events can substantially increase the movement of microplastics into rivers, particularly in regions with high plastic use and poor waste management. Qin et al. warn that climate change could worsen this problem as extreme rainfall becomes more frequent and intense, potentially creating short-lived but highly concentrated pollution pulses into rivers and marine environments.

Pediatric chemotherapy can leave lasting genetic scars on the healthy tissues of children treated for cancer, researchers report, potentially helping explain some of the long-term health problems childhood cancer survivors face decades later in life. Chemotherapy drugs such as cisplatin and carboplatin can kill cancer cells by damaging DNA. Yet, despite their benefits, they can also leave characteristic mutations in healthy tissues, particularly blood. However, the extent to which treatment produces mutations across different tissues in the same person remains unclear. This question is especially important for children, who may carry the consequences of chemotherapy-related mutations for decades and potentially face an increased risk of future cancers. Anna Wenger and colleagues used the highly sensitive duplex sequencing technology, NanoSeq, to detect mutations originating from individual DNA molecules in non-cancerous tissues from pediatric cancer patients. They also used targeted, gene-focused sequencing to examine the types and potential future consequences of chemotherapy-induced mutations. Wenger et al. found that non-cancerous liver tissue in children exposed to platinum-based chemotherapy accumulated mutation levels comparable to those of adult livers. The authors also identified a distinctive mutational signature found in cisplatin-exposed liver tissue, both healthy and cancerous, but not in other organs or cancer types, providing evidence that platinum treatment can leave specific patterns of lasting genetic damage in healthy tissue. “Wenger et al.’s study adds to the evidence that platinum agents can induce a high number of mutations in the normal [non-cancerous] tissues of children treated for liver cancer, for whom this type of chemotherapy is important for long-term survival,” write Sanjeev Vasudevan and D. Williams Parsons in a related Perspective. “Studies that follow treated children into late adulthood will enable earlier recognition of liver dysfunction and earlier interventions for any new cancers that arise in this population.”

American public health agencies don’t routinely test wastewater for sexually transmitted infections, but new research led by the University of Washington and the Washington State Department of Health found that such methods could be used to effectively identify Chlamydia trachomatis, the bacteria that causes chlamydia.

When a baby begins to cry, do you expect its caregiver to soothe it? Most infants do, according to a new study from researchers at the University of Illinois Urbana-Champaign. The study also found an association between the mental health of mothers and infants’ expectations about comforting behavior. 

A new report from Portland State University’s Homelessness Research and Action Collaborative (HRAC) and the OHSU-PSU School of Public Health offers an in-depth examination of how individuals navigate, survive and attempt to exit homelessness. Titled “Without a Map: A Lived Experience Study of the Paths People Create Through Homelessness," the publication serves as the second and final part of the Multnomah County-funded Pathways study. The first part of the study, released in April 2026, established through 541 surveys that 98% of unhoused participants want permanent housing. This final installment combines those survey findings with 29 in-depth journey-mapping interviews to show how people navigate homelessness and homeless services, what helps them move toward housing, what gets in the way and the many ways in which progress can sometimes stall or unravel. 

A study provides new insights into the biological alterations underlying the difficulties with precise fine movements observed in pediatric obstructive sleep apnea (POSA).