Lead and cadmium levels in raw bovine milk and dietary risk assessment in areas near petroleum extraction industries

P. 308-314Oil fields are a source of heavy metal pollution, but few studies have evaluated its impact on the intake of these contaminants through milk, an important food especially for children. From February 2015 to 2016, 118 samples of raw cow's milk, 14 of fodder and 8 of water in Southwest Iran were collected from farms close to oil fields or related industries. Lead (Pb) and cadmium (Cd) levels were evaluated by graphite furnace atomic absorption spectrometry. Mean ± SE in milk and fodder were 47.0 ± 3.9 and 54.0 ± 6.9 μg/kg for Pb, and 4.7 ± 1.0 and 3.5 ± 1.3 μg/kg for Cd. No Pb or Cd was detected in water. Most milk samples (82.2%) for Pb were above the permissible limits (20 μg/kg). Exposure to Pb and Cd from milk consumption was calculated in two scenarios: mean and maximum exposure for the age range of 2–90 years. The intake of an average Iranian adult (25 years, 60 kg b. w., 0.14 kg milk/day) would be 6.6 μg Pb and 0.66 μg Cd/day (WI of 46.2 and 4.6 μg, respectively), well below the risk values proposed by some international organizations, even in the maximum exposure scenario. However, Pb exposure for infants and toddlers may be closer to the risk values, since milk and milk products could be the main contributor to Cd and Pb, and small children consume 2–3 times more food than adults relative to their body weight. The risk of Pb and Cd exposure through milk close to oil fields should be considered and a monitoring plan for these contaminants is strongly recommended.S

The expression profile of detoxifying enzyme of tomato leaf miner, Tuta absoluta Meyrik (Lepidoptera: Gelechiidae) to chlorpyrifos

The tomato leafminer, Tuta absoluta (Meyrich) (Lepidoptera: Gelechiidae) is an important pest of tomato crops worldwide. The persistent use of organophosphate insecticide to control this pest has led to resistance. However, there is no report on the susceptibility and resistance mechanism of field population of Tuta absoluta (Meyrik) from Iran. Furthermore, the toxicity and impact of chlorpyrifos on metabolic enzymes in this pest remains unknown. The populations of T. absoluta from Rasht in Iran displayed LC30; 4332, LC50; 5010 and LC90; 7027 μg larva-1 to chlorpyrifos. The toxicity of chlorpyrifos could be synergized more bydiethyl maleate (DEM) and triphenylphosphate (TPP) whereas the synergistic effect of piperonylbutoxide (PBO) was not efficient as well as two other synergists. The synergistic effect ranged from 1.3 to 1.9-fold in 24 h and 1.2 to 1.5-fold in 48 h. The exposure with chlorpyrifos for 24 and 48 h significantly increased the activities of esterase and cytochrome P450-dependent monooxygenases, while there were no significant changes in glutathione-S-transferase. Field populations of T. absoluta from Iran displayed less susceptibility to chlorpyrifos and had a relatively high LC50 in compare to other previous studies. Esterases and cytochrome P450 monooxygenase might be involved in the metabolism, and hence resistance to, chlorpyrifos in this pest

DECREASE IN PUPATION AND ADULT EMERGENCE OF Plutella xylostella (L.) TREATED WITH HEXAFLUMURON

The oligophagous pest Plutella xylostella (L.) is a major crucifer pest in Tehran Province, Iran. Hexaflumuron is an insect growth regulator insecticide with good effects on immature insect stages. The objective of this study was to investigate the effects of two sublethal concentrations (LC10 and LC25) of hexaflumuron on some biological parameters of P. xylostella larvae, such as birth rate (b), death rate (d), finite rate of increase (λ), generation time (T), sex ratio, pupation rate, and adult emergence. Results showed that hexaflumuron decreased the total number of eggs and oviposition and post-oviposition periods, pupation, and adult emergence in the treated generation, b, and λ. Hexaflumuron also increased T, d, and the preoviposition period. However, sex ratio, percentage of pupation, and adult emergence in the offspring generation were not affected by hexaflumuron. Overall, these results indicated that sublethal concentrations of hexaflumuron can affect the biological parameters of P. xylostella

Determination of Lead and Cadmium in cow’s Milk and Elimination by Using Titanium Dioxide Nanoparticles

Background and Objectives: Heavy metals such as cadmium and lead are the most important toxins spreading through various ways like water, soil, and air in nature and easily enter human food chain. It is essential to determine the cumulative and harmful effects of these metals in nutrients, especially in cow milk because it is a unique source of food for all ages and it contains both essential and nonessential trace elements. Materials and Methods: A total of 100 milk samples were directly collected from healthy cows in Zabol located on east of Iran. The samples were tested to determine lead and cadmium residues. The rates of the heavy metals were determined using a Rayleigh atomic absorption spectrum equipped with hollow cathode lamps (HCL) at 283.3 nm for lead (Pb) and at 228.8 nm for cadmium (Cd). By using the photo-catalytic titanium dioxide nanoparticles, these toxic metals were removed. Results: The mean &plusmn; SD of the concentration of lead and cadmium in raw milk were 9.175&plusmn; 2.5 and 4.557 &plusmn; 1.081 ppb, respectively. Also, the P-values of Kalmogorov&ndash; Smiranov test for lead and cadmium were respectively 0.057 ppb (P>0.05) and 0.435 ppb (P>0.05). TiO2 nanoparticles were used to eliminate and remove lead and cadmium in milk samples. The results showed that there was a significant difference between lead and cadmium contents before and after adding TiO2 nanoparticles (P<0.05). Conclusions: According to results of this study, there was a very low amount of toxic metals. So, it seems that it is not necessary to use TiO2 in milk samples but these days it used frequently as an additive to some samples like milk to remove these pollutants. Keywords: lead, cadmium, milk, atomic absorption spectroscopy, TiO2 nanoparticle