In this study, the essential oil (EO) from leaves of Croton linearis Jacq was extracted and characterized by GC/MS. The EO hydrophilic-lipophilic balance required (rHLB) for nanoemulsion (NE) development was determined by the Griffin’ method. For evaluating the larvicidal effect against Aedes aegypti, the preparation process of NE was optimized, using a central composite design. It was also evaluated the possible toxic effect of NE in nontarget species. The leaves of C. linearis contain 1.50% of EO, enclosing 61 volatile compounds, mainly eucalyptol (26.66%). The best surfactant, oil:water ratio (4.5–5.0-91.5; % w:w:w), allows to achieve the optimal NE, using a stirring speed of 800 rpm, the addition rate of 0.5 ml/min, and a stirring time of 30 min. NE (with particle size = 163 nm) showed a larvicide effect (LC₅₀ = 17.86 μg/mL) more potent than the whole EO (LC₅₀ = 64.24 μg/mL). NE showed neither hemolytic effect nor cytotoxicity, and it was classified as a nontoxic product, according to the OECD class toxicity test (IC₅₀ > 2000 mg/kg). This product arises in a new green bio-larvicide that could be used for mosquito control.

The safe disposal of post-methanated distillery sludge (PMDS) in the environment is challenging due to high concentrations of heavy metals along with other complex organic pollutants. The study has revealed that PMDS contained high amounts of Fe (2403), Zn (210), Mn (126), Cu (73.62), Cr (21.825), Pb (16.33) and Ni (13.425 mg kg⁻¹) along with melanoidins and other co-pollutants. The phytoextraction pattern in 15 potential native plants growing on sludge showed that the Blumea lacera, Parthenium hysterophorous, Setaria viridis, Chenopodium album, Cannabis sativa, Basella alba, Tricosanthes dioica, Amaranthus spinosus L., Achyranthes sp., Dhatura stramonium, Sacchrum munja and Croton bonplandianum were noted as root accumulator for Fe, Zn and Mn, while S. munja, P. hysterophorous, C. sativa, C. album, T. dioica, D. stramonium, B. lacera, B. alba, Kalanchoe pinnata and Achyranthes sp. were found as shoot accumulator for Fe. In addition, A. spinosus L. was found as shoot accumulator for Zn and Mn. Similarly, all plants found as leaf accumulator for Fe, Zn and Mn except A. spinosus L. and Ricinus communis. Further, the BCF of all tested plants were noted <1, while the TF showed >1. This revealed that metal bioavailability to plant is poor due to strong complexation of heavy metals with organic pollutants. This gives a strong evidence of hyperaccumulation for the tested metals from complex distillery waste. Furthermore, the TEM observations of root of P. hysterophorous, C. sativa, Solanum nigrum and R. communis showed formation of multi-nucleolus, multi-vacuoles and deposition of metal granules in cellular component of roots as a plant adaptation mechanism for phytoextraction of heavy metal-rich polluted site. Hence, these native plants may be used as a tool for in situ phytoremediation and eco-restoration of industrial waste-contaminated site.