Rabia Yaqoob

Risk assessment of heavy metal and metalloid toxicity through a contaminated vegetable (Cucurbita maxima) from wastewater irrigated area: A case study for a site-specific risk assessment in Jhang, Pakistan

ABSTRACT The present research was conducted in district Jhang, Pakistan, to evaluate the concentration of metals/metalloids in soil and pumpkin (Cucurbita maxima) irrigated with domestic wastewater. Data revealed that the levels of metals and metalloids in soil samples from two different sites were below the safe limits except Cd, whereas, in the vegetable, the concentrations of As, Se, Ni, Mo, Pb, Mn, and Cu were above the safe limits. The levels of 12 metals and metalloids in the soil were ranged between 0.14 to 22.76 mg/kg at site-I and 0.16 to 22.13 mg/kg at site-II. The levels of these metals in the vegetable were found 0.35 to 61.13 mg/kg at site-I and 0.31 to 53.63 mg/kg at site-II. The transfer factor at both sites was highest for As and Co. The pollution load index recorded for Se, Cu, Cd, Mo, Pb, and Co was greater than 1. The daily intake of As, Mn, and Mo was above the oral reference dose, which reflects that the intake of pumpkin is not safe for the inhabitants of the selected sites. The control measures should be taken to phytoextract heavy metals and metalloids from polluted sites so as to reduce the health risks.

Insecticide Resistance in Bactocera zonata (Diptera: Tephritidae) in District, Sargodha, Pakistan

Present study was designed to investigate the role of non-specific esterases, glutathione-S-transferesaes and monooxygenases in insecticide resistance in Bactocera zonat. Flies were collected from Gauva orchids of Ajnala, Sargodha. For biochemical estimation of detoxifying enzymes, flies were exposed to the selected insecticides (i.e. Trichlorofon, Malathion and λ-cyhalothrin) for one hour, and then shifted to clean jars. The activity of insecticide detoxifying enzymes in the survivors and control were compared. The activity of insecticide detoxifying enzymes was higher in survivors compared to the susceptible flies (control). The activity of beta esterases, glutathione S-transfereases and monooxygenases of Trichlorofon and Malathion treated flies did not differ. However, both groups have higher activities of detoxifying enzymes compared to the control. Higher activities of insecticide detoxifying enzymes in survivors compared to the control groups indicate the involvement of these enzymes in insecticide resistance.

INSECTICIDE RESISTANCE IN THE GROUND SPIDER, Pardosa sumatrana (THORELL, 1890; ARANEAE: LYCOSIDAE).

Elevated levels of insecticides detoxifying enzymes, such as esterases, glutathione S-transferases (GSTs), and cytochrome P-450 monooxygenases, act in the resistance mechanisms in insects. In the present study, levels of these enzymes in the insecticide-resistant ground spider Pardosa sumatrana (Thorell, 1890) were compared with a susceptible population (control) of the same species. Standard protocols were used for biochemical estimation of enzymes. The results showed significantly higher levels of nonspecific esterases and monooxygenases in resistant spiders compared to controls. The activity of GSTs was lower in the resistant spiders. Elevated levels of nonspecific esterases and monooxygenases suggest their role in metabolic resistance in P. sumatrana. The reduced levels of total protein contents revealed its possible consumption to meet energy demands.