Biotransfer, bioaccumulation and detoxification of nickel along the soil - faba bean - aphid - ladybird food chain

Highlights: • Nickel (Ni) concentration increased in a dose-dependent manner along the food chain. • Ni biomagnified in faba bean roots and aphids while biominimized in ladybirds. • Ni is eliminated through honeydew of aphids. • Ni is eliminated by shedding of pupal exuviae during metamorphosis of ladybirds. Nickel release from anthropogenic and natural sources into the environment has resulted in biomagnification in terrestrial ecosystems. Here, we studied the biotransfer and toxicokinetics of nickel (Ni) along the soil < faba bean < aphid-ladybird food chain. The soil was spiked with the following Ni concentrations (in mg kg⁻¹ soil ww); T0 (0), T1 (25), T2 (50), T3 (75), and T4 (100). Our results revealed a significant elevation of Ni transfer with increasing Ni doses. The transfer coefficients (TC) indicate Ni biomagnified in soil to root and shoot to aphid >1 while the TC of the biominimisation of Ni in the aphid to ladybird was <1. The Ni removal from aphids through honeydew (excreta) and pupal exuviae during metamorphosis suggests a possible detoxification mechanism operating at two distinctive trophic levels, controlling the bioaccumulation of Ni along the examined food chain. Such toxicokinetics is not reported elsewhere and emphasize the need for future studies aiming to elaborate the possible mechanisms, potential components and physiological pathways associated with the bioaccumulation of Ni across food chains of the ecosystem.