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.

Using data from the James Webb Space Telescope (JWST), a group of astronomers has detected the chemical fingerprints of dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) in the atmosphere of exoplanet K2-18b, which orbits its star in the habitable zone. The detection has been published in The Astrophysical Journal Letters. 

In recent decades, the rate of pollen allergies has increased worldwide. One of the reasons being considered is the increase in atmospheric nitrogen pollutants. Now, a study published in the journal The Lancet Planetary Health estimates that grasslands fertilised with nitrogen release six times more pollen and that this pollen is five times more allergenic than that from unfertilised fields.

Research published in Science Advances concludes that the level of microplastics in the environment could be three times higher in 2060 than in 2019, even if one of the two more ambitious policy scenarios proposed by the OECD to reduce plastics is implemented.

Two independent clinical trials demonstrate the safety of stem cell therapies for Parkinson's disease. The papers, published in Nature, investigate the use of cells derived from human induced pluripotent stem cells and human embryonic stem cells, respectively. Parkinson's disease is characterised by the progressive loss of dopamine-producing neurons. Cell therapy, which replenishes dopamine-producing neurons in the brain, could provide a treatment with fewer adverse effects than current treatments. However, further research is needed to test the efficacy and benefits of these new therapies.

The year 2024 was the warmest year in Europe, with record temperatures in almost half of the continent, according to the European State of the Climate 2024, published by the Copernicus Climate Change Service (C3S) and the World Meteorological Organization (WMO). The report highlights 2024 as one of the ten wettest years since 1950 and estimates that storms and floods affected 413,000 people in Europe and at least 335 people lost their lives.

According to a meta-analysis published in Nature Human Behaviour, the widespread use of digital technology may be associated with lower rates of cognitive decline in people over the age of 50. The results of the study — which analysed 57 studies involving more than 400,000 people with an average age of 69 — seem to contradict the hypothesis that the daily use of technology weakens cognitive ability.

A model designed by a team of US researchers estimates that around 93 million computed tomography (CT) scans will be performed in the United States in 2023. The research, published in JAMA Internal Medicine, estimates that radiation from these scans could lead to 103,000 future cancers. If the same trend continues, cancers associated with these scans would account for 5% of all new cancer diagnoses per year in the US.

A team has developed a wearable designed to aid navigation for people who are blind or visually impaired. The system uses artificial intelligence (AI) algorithms to probe the environment and send signals to the wearer when approaching an obstacle or object. The technology, which is presented in Nature Machine Intelligence, was tested with humanoid robots and blind and partially sighted participants in both virtual and real environments.

The KATRIN (Karlsruhe Tritium Neutrino Experiment) team has published the most accurate measurement to date of the upper limit of the neutrino mass in the journal Science, establishing it at 0.45 electronvolts (eV), less than a millionth of the mass of an electron. The KATRIN experiment, launched in 2018 in Germany, will finalise its neutrino mass measurement campaign this year, having reached 1,000 days of data acquisition.