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Heavy Metals in Village Weaver Tissues Revealed Distinct Pollution Fingerprints Across Benue State

Village weaver perched among vegetation
Conservation · Threats

A study of wild village weavers (Ploceus cucullatus) from agricultural areas in Benue State, Nigeria, found that concentrations of six heavy metals differed among tissues and sampling locations. The authors assessed the birds as bioindicators—organisms whose tissues can reflect contamination in the environments where they live. The article was published on 16 April 2026 in the Asian Journal of Research in Agriculture and Forestry.

Researchers trapped village weavers at six sites and analysed liver, kidney, feathers, skin and bone for mercury, lead, arsenic, chromium, cadmium and copper. The birds used for the organ analyses were killed and dissected.

Bone, skin and feathers contained the highest concentrations

The concentrations varied both among organs and among locations. Bone, skin and feathers contained the highest concentrations across the tissue types examined. Mercury was particularly prominent in several of these tissues, with arsenic and lead also contributing to the site-specific profiles.

For example, birds sampled at Gboko had mean mercury concentrations of about 5.24 ppm (parts per million) in bone, 3.68 ppm in feathers and 1.27 ppm in skin. Mean arsenic concentrations at the same site were about 2.46 ppm in bone, 1.83 ppm in feathers and 0.45 ppm in skin. The study reports different concentration patterns at the other sampling locations.

Combined contaminant profiles separated the six sampling sites

The authors also analysed associations among metals and used the combined organ-metal profiles to compare sampling sites. A classification model assigned all eight birds in the test set to the correct sampling locations. The authors interpret this result as evidence that the six sites had distinct combinations of contaminants in this dataset.

Feathers contributed strongly to the differentiation among locations. Although the birds in this study were collected for internal-tissue analysis, feathers themselves can be sampled from live birds without removing internal organs. The authors therefore highlight feathers as a possible material for future non-lethal monitoring of heavy-metal contamination.

Using comparison thresholds for wildlife compiled from earlier literature, the authors classified the highest measured arsenic concentration, 2.47 ppm, and mercury concentration, 5.27 ppm, as high-concern levels. Lead reached 1.296 ppm, above their threshold for elevated exposure but below the value they listed as toxic, while cadmium, chromium and copper remained below the corresponding concern thresholds. These categories are comparisons with published thresholds, not health effects measured directly in the sampled village weavers.

The researchers conclude that village weavers can serve as bioindicators of spatial variation in heavy-metal contamination across agricultural landscapes in Benue State. The study provides tissue-specific baseline measurements for future pollution monitoring in the region.

Sources and image credit

  1. Egwumah, P. O., Iwar, M. I., & Hangeior, S. I. (2026). Evaluation of Weaver Birds (Ploceus cucullantus) as Bio-indicator of Contaminants in Benue State, North East and North West Agricultural Belts, Nigeria. Asian Journal of Research in Agriculture and Forestry, 12(2), 98–110. https://doi.org/10.9734/ajraf/2026/v12i2496Primary research article published 16 April 2026. The title contains the spelling Ploceus cucullantus, while the article text identifies the study species as Ploceus cucullatus. Wild village weavers from six sites in Benue State were analysed for Hg, Pb, As, Cr, Cd and Cu in liver, kidney, feathers, skin and bone.

Image: fr.zil / Wikimedia Commons — village weaver photographed in Saloum, Senegal, 26 July 2010; representative species image, not a bird from the Benue State contamination study; cropped to 16:9. · CC BY-SA 2.0 · Source

About this content: This story was produced with AI assistance within an editorial workflow developed by Wildlife Vagabond. Editorial responsibility remains with Wildlife Vagabond.How AI is used

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