pollution

After 10 days of meetings and beyond the deadline, representatives from more than 180 countries gathered at the UN headquarters in Geneva (Switzerland) have failed to agree on a global treaty against plastic pollution, the first legally binding one. This negotiation was, in principle, the last chance to reach an agreement, after the last meeting in Busan (South Korea) also ended without a treaty in December, two and a half years after negotiations began.

Ahead of the anticipated conclusion of a United Nations global treaty on plastics, a group of international experts calls for greater attention to health effects when addressing plastic pollution. The work, published in The Lancet, reviews current evidence on how plastics—including microplastics and plastic chemicals—affect health, and announces the launch of a new project to monitor these effects.

An international team has analysed data from more than 160,000 people in 40 different countries, including Spain, to study differences in the speed of ageing between regions and the factors responsible. According to the results, European countries show healthier ageing, while low-income countries are associated with accelerated ageing. Protective factors include physical factors such as air quality; social factors such as socioeconomic and gender equality; and sociopolitical factors such as freedom of political parties and democratic elections. The study is published in the journal Nature Medicine.

A team in the United States has analysed how exposure to environmental chemicals in previous generations influences the onset of the first menstruation. The researchers used data from the California Child Health and Development Study (CHDS) and analysed blood samples taken from 250 pairs from the 1960s. The results, presented at the annual meeting of the Endocrine Society in San Francisco (USA), show that although the average age of first menstruation remained stable between grandmothers and their daughters, it decreased by one year between daughters and granddaughters. Certain chemicals present in the blood of the mother and father were linked to the onset of puberty in their descendants, with stronger effects in granddaughters, according to the study, and with greater weight of male exposure.

Most research on the presence of plastics in the seas has focused on macro- and microplastics. Now, an international team has analyzed the presence of nanoplastics - smaller in size - in different locations and depths of the North Atlantic Ocean, including areas near the European coasts. The results suggest that these may account for the majority fraction of the total mass of plastic in the oceans and that the total mass of marine plastic may be greater than previously thought. The work is published in the journal Nature. 

Although tobacco consumption is declining in many parts of the world, there appears to be an increase in the number of lung cancer cases among non-smokers. One of the possible causes of this increase is air pollution. Now, researchers in the US, with Spanish participation, have analysed the genomes of 871 lung tumours in people from various locations who had never smoked. The results, published in the journal Nature, indicate that greater exposure to pollution is linked to an increase in the number of mutations, including those commonly associated with tobacco.

A model has analysed mercury concentrations in rivers around the world from 1850 to the present day. The results, published in Science Advances, conclude that levels have doubled and even tripled since the Industrial Revolution: before 1850, rivers carried approximately 390 metric tonnes of mercury to the oceans each year, and today that figure has risen to around 1,000 metric tonnes. According to the authors, these results have implications for human health and wildlife, as mercury compounds are neurotoxic, can accumulate in fish and pose a health risk through consumption.

A team from the United States has analysed data on modes of transport in more than 11,500 cities in 121 countries around the world, including Spain, representing 41% of the world's population. In addition to studying the factors that most influence the proportion of journeys made on foot or by bicycle, they estimate that if each city analysed increased the extent of its cycling network to the level of Copenhagen (Denmark), private vehicle emissions would be reduced by 6% and the public health benefits would be equivalent to around £37 billion. The results are published in the journal PNAS.

Lead exposure in children can affect their neurodevelopment. In the United States, the maximum blood concentration limit for this metal was lowered to 3.5 μg/dL (micrograms per decilitre) in 2021, down from 10 μg/dL in 2012. Now, a study has analysed data from more than 300,000 children in Iowa and found an association between higher concentrations and poorer school performance in reading and maths, even below the 3.5 μg/dL limit, prompting the researchers to reconsider this figure. The results are published in the journal JAMA Network Open.

Up to 1.4 billion people may be living in areas with soil contaminated by heavy metals such as arsenic, cadmium, cobalt, chromium, copper, nickel and lead, according to research published in Science. The paper, which used data from more than 1,000 studies, estimates that 14-17% of farmland worldwide could be contaminated by at least one toxic metal. Cadmium is the most widespread, especially in South and East Asia, parts of the Middle East and Africa.