Arsenic entomotoxicology.

Chemical pollution threatens insects, particularly agrochemicals, while risks from other globally relevant pollutants such as arsenic remain overlooked and understudied. To address this gap, an entomotoxicological review facilitates the identification and characterization of additional pollutants that pose risks to insects. This review critically assesses toxicological evidence on arsenic to determine its potential impact on insects. Evidence indicates that terrestrial insects are exposed through ingestion of contaminated food, water and soil, whereas aquatic insects accumulate arsenic from water, sediment and dietary sources. In insects, arsenic tends to accumulate in the gut predominantly as inorganic species, with only minimal amounts of organic forms. Excretion occurs via feces, exuviae, and eggs. Biochemically, arsenic induces oxidative stress and genotoxicity. At the organism level, it may cause deformities, developmental delays, and behavioral changes. At the population and community levels, arsenic may disrupt ecological organization. Based on the available entomotoxicological data, a reference guideline of 7.1 mg/kg is proposed for arsenic in soil to protect terrestrial insects, and a guideline of 0.055 mg/L is proposed for arsenic in water to protect aquatic insects. Although arsenic does not biomagnify through insect trophic chains, insects play a crucial role in transferring arsenic to other predators and can also disperse it across ecosystems. Mining, metallurgical, industrial and agricultural activities have been identified as the major sources of arsenic exposure to insects. Despite existing knowledge gaps, the available evidence supports the recognition of arsenic as a toxic contaminant with adverse effects on insects.