Three views from the same research group. Tang and colleagues modelled the risk that pesticide residues on farmland exceed the concentrations at which no harm to other species is expected, for 92 active ingredients across 168 countries, at about 10 km. Here we lay people over their map: how many live in the 10 km cells where farmland is at medium or high risk. A third view shows where pesticides end up in rivers, from Maggi and colleagues. Living in such a cell is not the same as being exposed; it marks where to look first.
People living in 10 km cells where farmland is at medium (amber) or high (red) risk, as a share of each state's population, for states above one million people. India is drawn on its official outline.
Rivers and groundwater. Maggi, F., Tang, F. H. M. and Tubiello, F. N. 2023. Agricultural pesticide land budget and river discharge to oceans. Nature 620: 1013–1017 (doi:10.1038/s41586-023-06296-x); data from figshare (doi:10.6084/m9.figshare.20452791), CC BY 4.0. River concentration is the modelled total of 92 active ingredients, averaged over the final year of a 30-year simulation driven by 2015 application rates, on modelled main river reaches at 0.25 degrees. Following the authors, concentrations above 1 µg/L are treated as exceeding safety levels; they report more than 13,000 km of river above that level, and name the Ganges among the rivers most exposed to pesticide runoff. The model underestimated measured concentrations, including country averages for India, so the authors judge the real threat in rivers is likely larger. Groundwater is not mapped: the authors estimate that 7.2 percent of net inputs, about 67,600 tonnes a year and nearly half of what is not broken down, leaches below the root zone, where it is prone to accumulate in aquifers; the dataset does not distribute it by place.
Data. Risk: Tang, F. H. M., Lenzen, M., McBratney, A. and Maggi, F. 2021. Risk of pesticide pollution at the global scale. Nature Geoscience 14: 206–210 (doi:10.1038/s41561-021-00712-5); maps from figshare (doi:10.6084/m9.figshare.10302218), CC BY 4.0. Risk classes as in the paper: negligible (score ≤ 0), low (0–1), medium (1–3), high (above 3, residues more than 1,000 times the no-effect concentration). Application rates are 2015 estimates. People: European Commission JRC, GHS-POP R2023A, 2020, 30 arc-seconds, CC BY 4.0, summed onto the risk grid by Tailenders Analytics. Shares of farmland are shares of farmland grid cells. Risk refers to ecosystems, not human health; the authors note the risk may be overestimated (one application a year, every field next to surface water, no drift loss) and underestimated (no legacy or banned products, no breakdown products). Country outlines: Natural Earth via world-atlas; India on the official outline used in the Tailwinds India maps. Boundaries do not imply any judgment on the legal status of any territory.