Surface sediments along the south of Caspian Sea were collected to evaluate the contamination of heavy metals. The result ranged (μg/g, Fe% dw): Pb(13.06-33.48); Ni(18.01-69.63); Cd(0.62-1.5); Zn(30.11-87.88); Cu(5.86-26.37) and Fe(1.8-4%) respectively. Cadmium showed higher EF when compared to other sites. Geoaccumulation Index value for Cd in most stations was classified as moderately contaminated and moderately to strongly contaminated, as well as the average of I(geo) of Cd (1.77 ± 0.35) suggested that surface sediments of Caspian coast were moderately polluted by this metal. The result of the Pearson correlation showed that there were significant positive associations between Ni, Cd and Zn (r = 0.44-0.76; p < 0.01).
Para-Phenylenediamine (PPD), the main aromatic amines used in the hair dye formation, and its four derivatives (2-chloro-p-phenylenediamine, 4-chloro-o-phenylenediamine, 2-nitro-p-phenylenediamine, and 4-nitro-o-phenylenediamine) were examined for their potential to produce single strand DNA breaks in human lymphocytes using the alkaline comet assay. Results revealed that all the tested chemicals within the range of doses from 100 microM to 500 microM showed the genotoxicity in a dose-dependent manner after the incubation of lymphocytes with these chemicals for 2 h. In this study, we first reported that PPD and its four derivatives can elicit the type of single strand breaks in human lymphocytes.
A study was conducted on the long term effects of nine heavy metals on the Chironomus plumosus and Culicoides furens larvae. This study tested the effect of the heavy metals on several generations of the larvae to observe the formation of increased hardiness against pollutants present within the aquatic habitat. From this study it was observed that susceptibility or sensitivity to heavy metals decreased with LC50 values becoming larger indicating a decreased toxicity level. Significant variations (p < 0.05) were observed between first generation and third generation culicoides for all metals and at all concentrations. Variations between third and fourth generation culicoides were also significantly different (p < 0.05) with the exception of chromium at 25 degrees C and nickel and lead at every temperature range group. The variation between all generations 4, 5 and 6 was found to be insignificant (p > 0.05). This would indicate that metal tolerance would have occurred in these generations and the effect of metals was less toxic to the culicoides. Generation 9 was found to have LC50 values (p > 0.05) the same as the LC50 values obtained in third generation culicoides. Thus it would appear that heavy metal resistance was developed when the organisms were exposed to prolonged exposure of the heavy metals but was lost when the organisms were bred in non-contaminated water.
Acute and chronic effects of insecticide-endosulfan on the survival and reproduction performance of Moina macrocopa were determined in a laboratory study. Endosulfan concentrations that cause 50% mortality (LC50) after exposure for 24 and 48 h were 3.34 and 0.16 mg L(-1), respectively. Average longevity, initial age of reproduction and intrinsic rate of natural increase were reduced at 0.002 mg L(-1). Fecundity was greatly reduced by about 70% at 0.0004 mg L(-1) and approximately 97% at 0.002 mg L(-1) as compared to control organisms throughout the whole life span of 15 days. If environmental concentration of endosulfan do not exceed 0.0004 mg L(-1), application of this insecticide is unlikely to induce detrimental effects on these cladoceran populations in agro-ecosystem.