Photodegradation of chlorpyrifos, malathion, and dimethoate by sunlight in the Sudan

Bacterial and vermi-remediation of soil contaminated with chlorpyrifos insecticide

“…Soil samples were collected from the River Nile first terrace (Gerf) in Shambat area (15.6587° N, 32.5302° E), Khartoum North, Sudan. The samples were air-dried at room temperature, cleaned from debris (to avoid any interaction during chemical analysis), gently crushed, passed through a 2 mm sieve and then sterilized in an oven at 180°C for 3 h according to Ishag et al (2019). One kilogram of sterile soil was mixed thoroughly with the chlorpyrifos as Tricel SL 48%.…”

“…The round bottle flask and its content were placed in a rotary evaporator under vacuum at 40°C to reduce the filtrate volume to 80 ml. The content of each treatment was then transferred to separatory funnel (capacity 1000 ml) then 300 ml distilled water and 10 ml of saturated sodium chloride solution were added and shaken for one min (the cork was opened several times to release pressure) (Ishag et al, 2019). The upper organic phase layer was transferred to another 500 ml separation funnel.…”

“…The organic phase was filtered through glass filter covered with 25 g of anhydrous sodium sulfate, and the solvent was evaporated by a rotary evaporator (Buchi, Postfach, Switzerland) at 40°C until dryness. The residues were reconstituted in 10 mL of nhexane and kept in 10 ml vials, tightly closed with Teflon lined screw caps and stored in the refrigerator at 4°C for GC analysis (Ishag et al, 2019).…”

“…Remediation can be done by various methods: chemical, biological and photochemical. Investigations of the potential bioremediation and photodegradation methods using indigenous microbes and sunlight photolysis are underway with promising results Shaer et al, 2013;Abdurruhman et al, 2015;Ishag et al, 2016Ishag et al, , 2017Abdelbagi et al, 2018;Ishag et al, 2019). However, it might be of relevant importance to assess other biological remediation methods (include the earthworms and bacteria) of the affected sites.…”

“…Chlorpyrifos has also been registered under different trade names in Sudan with annual imports exceeding 50 tons representing 17-25% of the total annual import of pesticides in Sudan (PPD, report 2006(PPD, report -2010. Chlorpyrifos was reported as a major contributor to soil contamination in storage soil and hot spots in Sudan (Ishag et al, 2016(Ishag et al, , 2019. Based on the above, the current study was initiated to investigate the potential of vermi-remediation combined with consortia of indigenous bacteria in removal of chlorpyrifos from contaminated storage soils and hot spots in Sudan.…”