Earthquakes May Be Pushing Toxic Heavy Metals Into Turkey’s Soils and Plants

When a magnitude 7.8 earthquake tore through southern Turkey in February 2023, the world watched buildings collapse and communities scatter. What nobody could see was a quieter disturbance unfolding underground and in the dust clouds that followed. A new study published in Environmental Monitoring and Assessment suggests that the seismic catastrophe may have physically rearranged the chemistry of the region’s soils, mobilizing heavy metals and delivering them into the tissues of plants growing in the hardest-hit provinces. The finding, based on painstaking analysis of soil and plant samples from five earthquake-affected provinces and two unaffected control regions, adds an unexpected dimension to the long list of earthquake consequences: a potential food safety problem that could linger long after the rubble is cleared.

The research team, led by Bahar Sürmelihindi of Gaziantep University and colleagues from several Turkish institutions, focused on two very different plants with two very different relationships to the human diet. The first was Hypericum perforatum, commonly known as St. John’s wort, a medicinal herb widely harvested across Anatolia and consumed in teas and herbal preparations. The second was Capsicum annuum, the pepper, a staple vegetable crop grown intensively in the region. By comparing metal concentrations in both species and in the soils beneath them across earthquake-affected Hatay, Kahramanmaraş, Malatya, Adıyaman, and Gaziantep with control samples from Aydın and Manisa, the researchers could isolate the signature of seismic disturbance from the background of ordinary agricultural and industrial contamination.

The analytical backbone of the study was inductively coupled plasma mass spectrometry, or ICP-MS, a technique capable of detecting trace elements at concentrations down to parts per billion. Soil and plant samples were digested and introduced into a plasma torch heated to roughly 10,000 Kelvin, where individual atoms were ionized and sorted by their mass-to-charge ratio. This allowed the team to quantify a broad suite of elements, from essential macronutrients such as calcium, magnesium, and potassium to the notorious toxic quartet of cadmium, chromium, lead, and mercury, along with nickel, which emerged as one of the most striking signals in the dataset.

The results were unambiguous. Concentrations of multiple heavy metals were significantly higher in both soils and plant tissues from the earthquake-affected provinces than in the control sites. Nickel, an element that is toxic to humans at elevated doses and a known carcinogen through inhalation, ranged from 16 to 24 milligrams per kilogram in pepper fruits and reached concentrations as high as 48 milligrams per kilogram in St. John’s wort samples. Translocation factors, which describe the ratio of metal concentration in plant tissues to that in the surrounding soil, indicated a moderate transfer of metals from soil into edible plant parts. In plain terms, the earthquake-affected landscape was not merely contaminated; the contamination was finding its way into the plants that people harvest, eat, and brew.

One of the most intriguing signals came not from the toxic metals but from the benign ones. Elevated levels of calcium, magnesium, and potassium in the leaves of St. John’s wort pointed to an additional and somewhat unexpected source of input: post-earthquake dust deposition and demolition-derived particulates. When thousands of buildings collapse, they release enormous quantities of pulverized concrete, masonry, plaster, and mineral dust that settle on soil surfaces and plant foliage. That dust carries its own elemental fingerprint, rich in the calcium silicates and carbonates of construction materials, and the researchers argue that this deposition contributed measurably to the mineral load observed in plant leaves. It is a reminder that an earthquake’s environmental footprint is not confined to the ground rupture; it extends into the air and settles back down over everything that grows.

The toxic metals told a more complicated story. Increased concentrations of cadmium, chromium, lead, and mercury were detected across the affected region, but they were particularly pronounced in the industrialized provinces. This spatial pattern suggests that the earthquake did not create these contaminants so much as redistribute and remobilize them. Southern Turkey hosts substantial industrial activity, including cement production, metal processing, and textile manufacturing, all of which leave legacy deposits of heavy metals in soils and sediments. Seismic shaking can crack containment structures, disturb buried waste, liquefy waterlogged sediments, and grind contaminated materials into finer, more mobile particles. Previous research on transient seismic stresses has shown that earthquakes can dramatically alter the permeability of soils and aquifers, changing how water and dissolved substances move through the subsurface. The new study is consistent with the hypothesis that such post-earthquake environmental changes, including soil degradation and particle redistribution, can increase the bioavailability of heavy metals and their uptake by plant roots.

The statistical evidence reinforces the pattern. Using one-way analysis of variance, the team found highly significant differences between earthquake-affected and control regions, with a p-value of 0.001, meaning there is only about a one in a thousand chance that the observed differences arose from random variation alone. In environmental monitoring, where natural heterogeneity in soil chemistry often muddies comparisons between sites, a result this clean across multiple elements and two plant species is notable. It suggests the seismic signal is real, systematic, and detectable through the noise of ordinary agricultural variation.

The choice of study plants matters for interpreting the findings. St. John’s wort is a medicinal plant whose dried aerial parts are consumed in concentrated forms, meaning that any metal burden it carries is delivered directly to consumers, often in the name of health. The species is also known from prior research to accumulate metals from soil, making it a useful biological monitor of environmental contamination. Peppers, by contrast, are a fresh food crop, and the detection of nickel at 16 to 24 milligrams per kilogram in the fruits raises immediate questions about dietary exposure thresholds. International food safety standards set limits for cadmium and lead in vegetables, and while the study did not perform a formal health risk assessment, the authors explicitly flag the need for further research into the potential food safety of edible plant tissues from the affected region. That caution is warranted: chronic low-level exposure to cadmium damages kidneys, lead impairs neurological development, and chromium in its hexavalent form is carcinogenic.

The broader significance of the study lies in what it reveals about disasters as environmental events, not just structural ones. Earthquakes are typically assessed in terms of casualties, building damage, and economic loss. But the physical perturbation of a landscape, the fracturing of soil horizons, the pulverization of contaminated building stock, the dust plumes that blanket agricultural land, constitutes a form of geochemical disturbance that science is only beginning to quantify. Comparable concerns have been raised after other major earthquakes, including observations of liquefaction and subsidence during the 2008 Wenchuan earthquake in China, which reshaped soils across vast areas. The Turkish study adds plant uptake to that picture, connecting the geology of a seismic event to the biology of the food chain.

For the affected communities, the practical implications are still taking shape. Much of the agriculture in Hatay, Kahramanmaraş, and the surrounding provinces continues on land that experienced intense shaking and months of demolition activity. Farmers, herbal collectors, and food processors in the region now have an evidence base suggesting that their soils and crops may carry an elevated metal burden, and that this burden reflects a combination of seismic mobilization, dust fallout, and pre-existing industrial contamination. The researchers call for continued monitoring and further investigation into food safety, a recommendation that aligns with a growing recognition among environmental scientists that disaster recovery must include environmental chemistry alongside engineering and reconstruction. The ground beneath southern Turkey was shaken once in a matter of minutes; the chemical consequences, this study suggests, may unfold over years, quietly moving through roots and leaves into the region’s food and medicine.

Subject of Research: Heavy metal mobilization and plant uptake in soils of earthquake-affected regions of Turkey

Article Title: Heavy metal distribution in soils and plants collected from earthquake-affected regions of Turkey: a comparative assessment of Hypericum perforatum L. and Capsicum annuum L.

Article References: Sürmelihindi, B., Gökpinar, B., Morcali, M. H., Yilmaz, Y., Aksan, M. E., Koçer, F., Karakoç, S. B., & Şekeroğlu, N. (2026). Heavy metal distribution in soils and plants collected from earthquake-affected regions of Turkey: a comparative assessment of Hypericum perforatum L. and Capsicum annuum L.. Environmental Monitoring and Assessment, 198(10), Article 1108. https://doi.org/10.1007/s10661-026-15955-1

Image Credits: AI Generated

DOI: 10.1007/s10661-026-15955-1

Keywords: heavy metals, earthquake, Turkey, soil contamination, Hypericum perforatum, Capsicum annuum, ICP-MS, nickel, food safety, plant uptake, dust deposition, environmental monitoring