Impact of bio-accumulated heavy metals on silkworm (Bombyx mori L.) and silk quality reared on mulberry plant grown in heavy metal impregnated soils of Faisalabad, Pakistan.

Abstract

The present study was planned to evaluate the entrance of heavy metals into the food chain of Bombyx mori L.(silk worm) from (mulberry) plants irrigated using heavy metals containing synthetic effluents. The soil, plant, silkworm larvae, silk glands and their excreta were sampled to determine heavy metals amount using Atomic Absorption Spectrometry (AAS). The amount of heavy metals accumulated by synthetic effluent to soil was increased with pH of the effluent. However the bio-accumulation of Heavy metals in Morus alba L. leaves and Bombyx mori L. larvae was higher when the effluent pH was in low acidic range. Bombyx mori L. excreted significant amount of heavy metals but still most of heavy metals remained inside its body. The significant amount of heavy metals detected in soil, leaves, larvae and faeces were recorded. Significant impact of heavy metals bioaccumulation was reported on its life cycle and growth (Body weight and body length) of silkworm larvae by application of different concentration and pH of synthetic effluent of heavy metals. Heavy metals present in Bombyx mori L.body were responsible for toxic effects on its life cycle. 1st instar of Bombyx mori L. was most affected by heavy metals toxicity, Body length, body weight of Bombyx mori L. decreased with increase in heavy metals amount bio-accumulated in larval body. Higher heavy metals concentration in larval body increased Bombyx mori L. death rate significantly. Significant difference in food consumption, coefficient of food-utilization, and silk yield were reported which were also studied and observed to get proper results.