Background and Aims: The increasing use of silver nanoparticles (AgNPs) in the future will result in pouring this material into the environment and will cause health and environmental problems to humans and other organisms. In this context, the use of biological indicators is necessary for environmental monitoring and control. The purpose of this study was to evaluate the accumulation capacity of AgNPs in the gills, intestines and hepatopancreas of freshwater crayfish, as an indicator of environment.Material and Method: In this study, 15 adult male freshwater crayfish (Astacus leptodactylus) were caught from the Aras River (north-west of Iran). Crayfish were exposed to five concentrations of AgNPs colloid (0, 0.1, 0.25, 0.5, and 1 mg/l) for a period of 6 days. The concentration of silver in the intestines, gills and hepatopancreas were measured using Phoenix 986 atomic absorption. The One-Way ANOVA was used to compare the levels of AgNPs in the tissues.Results: According to the findings of this study the highest accumulation of silver were observed in the gill tissue. Also the accumulation amount in the hepatopancreas and intestinal tissues depends on the concentration of AgNPs in the water, so that at lower concentrations, accumulation in the intestine was higher than the hepatopancreas but in higher concentrations, accumulation in the hepatopancreas was higher than the intestine.Conclusion: In this study, the silver BIOCONCENTRATION was dependent on the target tissue and concentration of AgNPs in the water. Also, due to the higher concentration of silver in the gills of freshwater crayfish in comparison with other tissues, this organ can be recommended as a suitable target tissue. More studies are needed to obtain more comprehensive information about the impact mechanism of AgNPs accumulation in different tissues of this aquatic organism.

Background: Artemia urmiana are small crustaceans that because of its non-selective filter feeder pattern potentially may absorb high level of heavy metals through their living environment.In this study, the effects of different levels of cadmium and copper on survival, catalase activity and metals BIOCONCENTRATION rates inA. urmiana nauplii have been investigated.Methods: The research was carried out in February 2012 at University of Tehran, Tehran, Iran.First experiment was conducted in nine concentrations with six replication, then LC50 and probable interactions between experimental metals were evaluated. In the second experiment, concentrations of metals absorbed byArtemia and catalase activity were measured based on the acute toxicity indices, including NOEC, LOEC and LC50 at individual and mixed concentrations.Results: The toxicity of copper sulphate (LC50=29.87) was 2.5 times greater than cadmium chloride (LC50=79.08) and the toxicity interaction between cadmium and copper was synergistic.The rate of copper uptake inArtemia was higher than cadmium and increased concentration of heavy metals significantly decreased the BIOCONCENTRATION factor. Comparison of mixed and individual concentrations showed that cadmium significantly decreased copper uptake, while it seems that cadmium BIOCONCENTRATION was improved consequently. Biochemical analysis showed that the catalase activity was affected undesirably in different individual and mixed concentrations; however, these changes were not significant.Conclusion: A. urmiana nauplia seems to be highly resistant toward cadmium and copper in their culture medium and demonstrated excessive potential for uptake of heavy metals from their rearing environment.

To determine the acute toxicity and bioaccumulation of mercuric chloride in Rutilus frisii kutum, specimens of the fish were exposed to various concentrations of the chemical in water. We carried out ten treatments with three replicates and one control for each of the chemicals using the static O.E.C.D. method in 55 liter tanks each containing 14 fingerlings. During the experiments, the average pH was recorded as 7.8, total hardness was measured to be 255 mg/l, average water temperature was 27±1 degrees centigrade and dissolved oxygen was 7.2 mg/l. Mean LC50 values of Hgcl2 for juvenile R. frisii kutum with mean weight 1±0.2 grams were 0.102 and 0.086 mg Hg/l at 24h and 96h, respectively.The bioaccumulation values during 24h in muscle tissue, kidney and gill were 1.55, 16.1 and 22.7 mg Hg/l respectively. The values during 96h exposure were 2.8, 16.8 and 26.65 mg Hg/l in tissue, kidney and gill respectively. The BIOCONCENTRATION values for muscle tissue, kidney and gill during the first 24h were 14.75, 153.39 and 216.11 after 96h were 33.8, 198.1 and 313.5 times that of the environment. These results show the bioaccumulation to be the highest in gill followed by kidney and muscle tissue. The study suggested direct relationship between mercury concentration in and its bioaccumulation in the fish organs tissue.

In this study, uptake and accumulation of cadmium (Cd) by Malva parviflora L. and as well as some growth parameters were investigated in hydroponic medium. After collecting from the industrial area of Khuzestan steel company, the seeds were sown on the pots containing humus commercial soil and kept under controlled conditions. 47-day-old plants were transferred to nutrition solutions including 0 (control), 10, 50 and 100 μ M of Cd. The plants were harvested at 0 (control), 1, 2, 6, 10 and 14 days after supplement with Cd treatments. Based on these results, Cd concentration in shoots and roots showed an increase with increasing Cd concentration of medium. However, both concentration and accumulation of Cd in the roots exhibited higher values than that in the aboveground organs. At 100 μ M Cd, maximum Cd concentration in the shoot and root was assayed 224 and 1548 mg/kg DW, respectively. In each harvest time, with increasing Cd concentration of medium, length, fresh weight, dry matter of shoots and roots, blade area also index of tolerance significantly decreased in comparison with control. With regard to TF < 1, it seems that the roots of Mallow mainly possess higher capability than aerial parts to accumulate Cd. In summary, M. parviflora prevent Cd toxicity effects probably by reducing more translocation of Cd to the shoots.