Impact of Bio-Accumulated Cadmium in Bombyx mori L. Reared on Mulberry Plants Grown in Heavy Metal-Impregnated Soils in Faisalabad, Pakistan

Industries in Faisalabad are discharging their wastewater containing different kinds of heavy metals without treatment into sewerages. This wastewater is used to irrigate different crops and trees. This study was planned to observe the entry of Cd from inorganic to organic source and its effects on the lifecycle of Bombyx mori (L.). Mulberry plants were irrigated with Cd-containing synthetic effluents of different concentrations (25 to 200 mg/l) at pH 5, and different levels of pH (3 to 5) at 100 mg/l, to check against different instars of silkworm. The amount of Cd in the samples of soil, mulberry leaves, silkworm larvae, silkworm faeces and silk glands were determined by using atomic absorption spectrophotometry (AAS). The results showed that B. mori can be used as an indicator of Cd pollutants because its body weight, body length and mortality rate was directly related to Cd concentration. Greater toxicity to silkworms was observed at higher accumulation of Cd in mulberry leaves. Maximum accumulation of Cd in soil, mulberry plants, silkworm larvae, silk glands and silkworm faeces was observed at 200 mg/l Cd and pH 5. The maximum accumulations observed were 99.89 mg/kg, 95.67 mg/kg, 61.32 mg/kg, 58.97 mg/kg and 6.59 mg/kg, respectively. Silkworms can be successfully used as an indicator of heavy metal pollutants and their role can further be marked with changes in the development.