Assessing the impact of waste co-incineration at the Anhovo cement plant (Slovenia) on the regional cancer burden

Our plain-English summary of Assessing the impact of waste co-incineration at the Anhovo cement plant (Slovenia) on the regional cancer burden, by V. Zadnik, M. Birk, T. Oblak, et al (Radiology and Oncology, 2025).

The study

• Authors: V. Zadnik, M. Birk, T. Oblak, M. Jurtela, S. Tomsic, K. Lokar, A. Mihor, N. Bric, M. Mlakar, A.D. Konjevic, T. Zagar
• Journal: Radiology and Oncology
• Published: 2025;59(3):412-424
• Read it: PubMed · Publisher · Free full text

Abstract

Background: This epidemiological study aims to assess the cancer risk potentially associated with environmental exposure resulting from cement production and waste co-incineration at the Anhovo cement plant in Western Slovenia and to develop a strong and reliable methodological framework for the long-term surveillance of environmentally related cancer risks in small geographical areas.

Materials And Methods: We integrated all the available data sources: cancer cases from the population-based Slovenian Cancer Registry; background population; and available measurements on exposure to air PM10 particles and chromium (Cr) in the soil in the municipality of Kanal and the wider Goriška region. Relative risks of cancer in small geographical areas were estimated using Bayesian hierarchical spatial models and the population attributable fractions of the modelled risk factors were calculated. The point source analysis compared the cancer risk near the cement plant to that in more distant areas.

Results: The analysis did not reveal any excess cancer incidence in the area of the Anhovo cement plant or an association with the PM10 particles and Cr in the soil. The incidence of mesothelioma remains high in the region, but stable in the last two decades.

Conclusions: In view of the environmental pollution caused by either historical cement production or the potential impact of current waste co-incineration activities in Kanal, we strongly recommend that a follow-up epidemiological study be carried out in the next 10 to 20 years. The methodological framework established in the present study provides a foundation for the ongoing surveillance of the cancer burden in the region.

© 2025 Vesna Zadnik et al., published by Sciendo.

In plain English

This study examined whether people near the Anhovo cement plant in Western Slovenia, which burns waste as fuel, had more cancer than expected. The authors used Slovenian Cancer Registry cases from 2001 to 2020 (mesothelioma up to 2022), analysing 2011 to 2020 cases with small-area statistical models. They compared settlements, tested present-day PM10 air pollution and soil chromium levels, and compared distance zones around the plant's chimneys. Apart from two exceptions, they found no statistically significant excess of all cancers, lung cancer, non-Hodgkin's lymphoma or sarcoma near the plant or with higher pollution. Both concerned non-Hodgkin's lymphoma: one in the highest PM10 category, based on few cases, and one in the zone farthest from the plant. Asbestos was not analysed, but mesothelioma remained high: in 2018 to 2022 the age-standardised rate was 43.3 per 100,000 in Kanal municipality versus 0.8 per 100,000 in Slovenia. With mesothelioma excluded, Kanal's age-standardised cancer rate matched the Slovenian average for 2016 to 2020. Because solid cancers usually take 15 to 20 years to develop, the authors said waste-burning effects may not yet show and recommended repeating the study.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Population-based small-area geographic and correlational (ecological) epidemiological study. It used standardised incidence ratios smoothed with Bayesian hierarchical spatial (BYM) models, population attributable fractions, exposure-category analyses and a point source (distance-from-chimneys) analysis.
• Who was studied: Cancer cases in the population-based Slovenian Cancer Registry diagnosed 2001 to 2020 (mesothelioma up to 2022). The geographic analysis covered 2011 to 2020 at three levels: settlements in the municipalities of Brda, Kanal, Nova Gorica and Tolmin (Western Slovenia); settlements in Kanal municipality alone; and a smaller Kanal area where soil chromium was sampled.
• Exposure: Four exposure measures were used. (1) Modelled average daily PM10 air concentrations for 2021 on a 1 km by 1 km grid (12.2 to 15.4 μg/m3, below official limits), split into three categories. (2) Soil chromium measured at 30 locations in 2023 (14 to 76 ppm), split into three categories. (3) Residential distance from the plant's three chimneys (0 to 2 km, 2 to 5 km, 5 to 10 km). Present-day levels stood in for past exposure. (4) The geographic analysis focused on non-asbestos environmental exposures; asbestos was not modelled.
• Main results:
  • Mesothelioma age-standardised incidence (World standard) for 2018 to 2022 in the municipality of Kanal was 43.3 per 100,000 population.
  • Mesothelioma age-standardised incidence (World standard) for 2018 to 2022 in Slovenia overall was 0.8 per 100,000.
  • In Kanal, the mesothelioma incidence trend has been stable since 1999, with an average of 6.5 cases per year in 2013 to 2022.
  • In Slovenia as a whole, mesothelioma incidence declined from 2014 to 2022 by an average of 3.1% per year (95% CI 3.4% to 2.8% decline).
  • Almost half of all mesothelioma cases in Slovenia are diagnosed in residents of the Goriška region.
  • With mesothelioma cases excluded, the age-standardised all-cancer rate for Kanal corresponded to the Slovenian average for 2016 to 2020 and was stable over 20 years.
  • In the four-municipality settlement analysis for all cancers combined, the settlement of Deskle had a relative cancer risk about 30% higher than the average for the combined municipalities.
  • In the four-municipality analysis, 3.6% of all cancer cases were attributed to differences in socio-economic deprivation and 3.2% to differences in modelled PM10.
  • Within Kanal municipality, no settlement showed increased relative cancer risk.
  • Within Kanal municipality, 4.4% of new cancer cases were attributed to deprivation differences, and none could be attributed to PM10 differences.
  • One exception in the Kanal PM10-category analysis: non-Hodgkin's lymphoma in the highest PM10 category on the 1 km grid had SIR 4.18 (95% CI 1.14 to 10.71). This was based on 4 of the 6 non-Hodgkin's lymphoma cases in Kanal, and the authors said it could reflect multiple testing.
  • Relative risk was not higher in any soil chromium category for any cancer type studied.
  • In the zone within 2 km of the chimneys, 193 of 2,484 inhabitants developed cancer between 2011 and 2020.
  • Residents living closer to the chimneys did not have a statistically significant increased cancer risk compared with residents living further away.
  • Risk in the 2 to 5 km zone was lower than in the 5 to 10 km zone for all cancer types analysed, so no clear distance trend was seen.
  • There were no non-Hodgkin's lymphoma cases within 2 km of the chimneys. In the farthest (5 to 10 km) zone, the non-Hodgkin's lymphoma SIR was statistically significant: 1.71 (95% CI 1.04 to 2.64).
• The authors' conclusion: The authors concluded that the analyses showed no statistically significant increase in cancer incidence in the area of the Anhovo cement plant, except for the already known high risk of mesothelioma. Because of cancer latency, they said they could not rule out an effect of more recent waste co-incineration, and they recommended a follow-up study.
• Limitations the authors state:
  • Cancers diagnosed in 2011 to 2020 likely reflect exposures around 2000 or earlier, before waste co-incineration began at the plant.
  • Solid tumours usually take 15 to 20 years to develop, so the study needs repeating.
  • The authors stated the study should be repeated 10 to 15 years from now.
  • Permanent residence at diagnosis was used as a stand-in for exposure.
  • No residential history was available.
  • Present-day PM10 and chromium levels were used to approximate past exposure, so results should not be read as causal.
  • Data on confounders were limited, including smoking; a deprivation index was used as a proxy for smoking.
  • Small populations and few cases make estimates unstable.
  • The form of chromium was unknown. The authors note that only hexavalent chromium is carcinogenic and that the measured chromium was mainly geogenic.
  • The study did not address occupational exposure or model dioxins or other relevant pollutants.

Topics

Medical terms in this study, explained in our Lexicon: Environmental Exposure, Cancer Registry, Relative Risk, Population Attributable Fraction (PAF), Mesothelioma.

Related studies

• Time trends and spatial patterns in the mesothelioma incidence in Slovenia, 1961-2014 — V. Zadnik, M. Primic Zakelj, et al. (2017)
• Mortality in a cohort of cement workers in a plant of Central Italy — F. Giordano, V. Dell'orco, et al. (2012)
• Asbestos fiber concentration in the area surrounding a former asbestos cement plant and excess mesothelioma deaths in residents — S. Kumagai, N. Kurumatani (2009)
• The relationship between malignant mesothelioma and an asbestos cement plant environmental risk: a spatial case-control study in the city of Bari (Italy) — M. Musti, A. Pollice, et al. (2009)
• Treatment and recycling of asbestos-cement containing waste — F. Colangelo, R. Cioffi, et al. (2011)
• Sustainable bio-hydrothermal sequencing treatment for asbestos-cement wastes — D. Spasiano, V. Luongo, et al. (2019)

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