The persistence toxicity of four insecticides against adult Hippodamia varigata (Coleptera: Cocinellidae).

In order to investigate the effects of four insecticides on Hippodomia variegata (Coleoptera: Coccinellidae), the predator of Aphis fabae, an experiment was carried out using IOBC/wprs method. Persistence toxicity of insecticides has been evaluated in the greenhouse condition. The insecticides abamectin 1.8 EC, deltamethrin 2.5 EC, imidacloprid 350 SC, and proteus OD 110 were used at recommended field rates. The insecticides were applied on broad bean foliage using a hand sprayer, until run-off. Contact toxicity of aged residues of insecticides on adult predator was evaluated using the cage-method. The trials were laid out in randomized complete design (CRD) with 3 replicates and an untreated check. The arcsine transformation was used for analysis. The mortality of adult predator, after 24 h contact with fresh residues of abamectin, deltamethrin, imidacloprid and proteus were 53.4, 52.1, 63.4 and 65.1%, respectively. After 5 days the effect of residues decreased so that the adult mortality diminished to 32.4, 36.5, 56.1 and 57.5% for mentioned above insecticides. 15-day old residues lead to 8.8, 23.1, 56.3 and 57.5%; and 31-day old residues lead to 8.8, 22.7, 29.5 and 41.7% mortality for these insecticides, respectively. Based on this study, abamectin and deltamethrin with persistence less than 5 d are classified as short lived (Class A) while imidacloprid and proteus with persistence between 16 to 31d, classified as moderately persistent (Class C) compounds.

Mercury release from dental amalgam restorations after magnetic resonance imaging and following mobile phone use.

In the 1st phase of this study, thirty patients were investigated. Five milliliter stimulated saliva was collected just before and after MRI. The magnetic flux density was 0.23 T and the duration of exposure of patients to magnetic field was 30 minutes. In the 2nd phase, fourteen female healthy University students who had not used mobile phones before the study and did not have any previous amalgam restorations were investigated. Dental amalgam restoration was performed for all 14 students. Their urine samples were collected before amalgam restoration and at days 1, 2, 3 and 4 after restoration. The mean +/- SD saliva Hg concentrations of the patients before and after MRI were 8.6 +/- 3.0 and 11.3 +/- 5.3 microg L(-1), respectively (p < 0.01). A statistical significant (p < 0.05) higher concentration was observed in the students used mobile phone. The mean +/- SE urinary Hg concentrations of the students who used mobile phones were 2.43 +/- 0.25, 2.71 +/- 0.27, 3.79 +/- 0.25, 4.8 +/- 0.27 and 4.5 +/- 0.32 microg L(-1) before the amalgam restoration and at days 1, 2, 3 and 4, respectively. Whereas the respective Hg concentrations in the controls, were 2.07 +/- 0.22, 2.34 +/- 0.30, 2.51 +/- 0.25, 2.66 +/- 0.24 and 2.76 +/- 0.32 microg L(-1). It appears that MRI and microwave radiation emitted from mobile phones significantly release mercury from dental amalgam restoration. Further research is needed to clarify whether other common sources of electromagnetic field exposure may cause alterations in dental amalgam and accelerate the release of mercury.

Polycyclic aromatic hydrocarbons study and toxic equivalency factor (TEFs) in Tehran, Iran.

Polycyclic aromatic hydrocarbons (PAHs) are toxic pollutants released by various urban combustion sources. Benzo[a]pyrene (BaP) is a representative member of the class of PAHs. Health risk assessment associated with inhalatory PAHs uptake is often estimated on the basis of the BaP concentrations in air. Atmospheric particulate PAHs concentrations were measured at five locations in Tehran, Iran. Sixteen PAHs were extracted from the airborne particles and analyzed by HPLC. Total PAHs concentrations (16 compounds) at five station Arjanteen, Enghelab, Azadi, Bahman, Haft Houz were respectively, 70.2, 96.5, 130, 79.1, 44.1 ng/m(3). The information obtain from the present study indicated that mean of human carcinogens are: benzo[a]antheracene (0.17-4.76 ng/m(3)), chrysene (1.74-3.62 ng/m(3)), benzo[b]fluoranthene (0-5.25 ng/m(3)), benzo[k]fluoranthene (0.32-1.72 ng/m(3)), benzo[a]pyrene (1.41-3.82 ng/m(3)), dibenzo[a,h]anthracene (0.33-2.13 ng/m(3)), and indeno[1,2,3-cd]pyrene (0.25-11.08 ng/m(3)). The development and the establishment of a toxicity equivalency factor (TEF) are used in the assessment of mixtures containing PAHs. The contribution of the carcinogenic potency of BaP alone is in the range of 49.6-76.3% of the total carcinogenic activity. The annual number of lung cancer cases (persons per million) among Tehran residents (population = 10 millions) attributable to these carcinogenic PAHs compounds in 2005 was estimated at 58 persons per million. In Tehran urban areas vehicular emission are the primary contributor to PAHs concentrations, with additional local contributors like industrials emissions.

Side-effects of three pesticides on the predatory mite, Phytoseiulus persimilis (Acari: Phytoseiidae).

Side-effects of three commonly used pesticides in Iran were evaluated on an introduced strain of the predatory mite. Phytoseiulus persimilis Athias-Henriot, reared for about 10 years without exposure to any pesticides. Application of pesticides was carried out either to detached bean leaves using a Potter tower at 1 mg wet deposit per cm2 or by a hand sprayer on bean plants until run off. According to an EPPO decision making scheme, pirimiphos-methyl was found to be harmful (E=90.8%) and heptenophos harmless (E=-3.7%) to the predatory mite in the residual initial toxicity tests. For determination of the hazard class of malathion a field test was found to be necessary (E=59.8%). Categories of 1, 2, 3 were determined for heptenophos, malathion and primiphos-methyl, respectively, using IOBC classification. Despite being harmful, it is possible to use pirimiphos-methyl 10 days before release of P. persimilis. Investigation of the contribution of both lethal and sub-lethal effects to total impact indicated the dominance of lethality in the case of pirimiphos-methyl, while malathion acted by both mechanisms. Heptenophos did not have negative effects on fecundity of P. persimilis but rather caused a higher rate of fecundity in comparison with the control. The mortality found in the heptenophos test was not significantly different from the control.