The current study is an endeavour to measure the bioaccumulation potentials of heavy metals in different parts of chilli plants (Capsicum annuum L.) grown in artificially contaminated soil with various concentrations of Cr and Pb. The concentrations of heavy metals were estimated by Atomic Absorption Spectroscopy (AAS) technique. The mean concentration of Cr and Pb accumulated in different parts of plants in high, medium, and low levels of contamination was in the following order: roots > leaves > shoots > fruits. Cr concentration in fruits was lower than that of the WHO standard. However, fruits grown on medium contaminated soil contained 0.695 mg/kg Cr which did not follow the safe guideline by SEPA. A significant amount of Pb was traced in fruits grown in highly contaminated soil that exceeded the standard limit set by FAO/WHO. Accumulation of Pb was higher than Cr at different levels of contamination in every part of the chilli plants. The transfer factor for Cr and Pd was found in the following order, leaves > shoots > fruits> roots and leaves > shoots > roots > fruits, correspondingly at every level of contamination. The bioconcentration factors were higher in Pb than Cr. The daily intake of metals in combination with health and carcinogenic risk indexes indicated that the edible parts of chilli plants are safe to consume as recommended by SEPA/WHO/FAO. The present study can be considered a reference for assessment and monitoring of heavy metals associated with human health risks in chilli plants at different industrially contaminated sites.

This study aimed to investigate the bioaccumulation and elimination of lead (Pb) in Fejervarya limnocharis frogs as well as to determine the genotoxic effects of direct Pb exposure at different concentrations and lengths of time. Four varying concentrations (0, 5, 10 and 20 mg.L-1) of lead acetate (Pb(CH3COO)2) solutions were injected intraperitoneally into F. limnocharis. The concentration of Pb in the water samples used to house the frogs and the concentration of lead in frog muscle tissues were analysed at 24, 48 and 72 hours after injection by inductively coupled plasma optical emission spectrometry. Pb was detected at a level that exceeded the standard (0.03 mg.kg-1) in all samples of frogs injected with Pb. The water samples indicated that the Pb concentrations were significantly different from the control (p < 0.05), except for the 5 and 10 mg.L-1 concentrations after 24 hours groups and 5 mg.L-1 concentration after 48 hours group. Only the concentration of the water in the 20 mg.L-1 for 72 hours group exceeded the standard (0.05 mg.L-1). Genetic differentiation was studied by inter simple sequence repeats (ISSR) with dendrogram construction and analysis of genetic similarity (S) for each duration of exposure. A total of 1158, 1205 and 1277 bands were generated by ISSR for the 24, 48 and 72 hours groups, respectively. In each dendrogram, individual injections with the same Pb concentration clustered together, and it appeared that higher concentrations resulted in greater genotoxicity. Genotoxicity was concentration- and time-dependent, with a correlation between the concentration and S-value for the 72 hours group (R2 = 0.77, p < 0.05). In addition, this study could provide a basic application to develop F. limnocharis as a biomarker for Pb contamination by measuring genotoxic consequences.

The behavior of lead species from Tagus estuarine water collected during winter (January), spring (April), and summer (June) seasons were evaluated. Water samples were titrated with Pb+2 followed by differential pulse anodic stripping voltammetry (DPASV). Experimental voltammetric values were interpreted assuming a macromolecular heterogeneous ligand described in a simple way by two types of binding sites, CL1 and CL2, where CL1 is related to stronger binding groups with lower concentration compared to CL2. Water quality parameters like dissolved organic matter (DOC), pH, salinity, temperature, and total lead concentration were measured during the period under study. The results pointed to a higher concentration of CL1 and CL2 sites in April probably due to the phytoplankton bloom. The decrease of KL1 with the increase of salinity from winter to summer may be caused by the increase of major cations (as Ca2+) in solution. The trend of KL2 followed the pH shift in all seasons since an increase of pH favors Pb2+ complexation with CL2 sites. Finally, the decrease of DOC in summer could be responsible for the decrease in the concentration of the different sites in solution from April to June, with a similar decrease of 35±3% for all of them.

Eight bacterial strains were isolated from lead-cadmium contaminated soil samples obtained from a Tungsten mine. Pb2+ and Cd2+ adsorption abilities of the isolated strains were screened. One isolate, referred to as Strains S, was selected for further study because of its relatively high adsorption ability. Five factors affecting adsorption of Pb2+ and Cd2+ were studied, namely, the initial concentration of Pb2+ or Cd2+, temperature, pH, biomass of Strains S, and adsorption time. Results indicated that Strains S best adsorbed Pb2+ when the initial concentration of Pb2+ was 100 mg/L, temperature was 35°C, pH was 6.5, dosage was 0.1 g, and adsorption time was 20 min. In contrast, Strain S best adsorbed Cd2+ at an initial Cd2+ concentration of 100 mg/L, temperature of 40°C, pH 6.5, dosage of 0.1 g, and adsorption time of 20 min. The experimental data were fitted to the Langmuir and Freundlich adsorption isotherm models, and the results indicated that the Langmuir model better fitted the experimental data. The results of infrared spectroscopy revealed that the functional groups involved in adsorption of Cd2+ and Pb2+ were -OH, -NH2, -S=O and -P=O. Using 16S rDNA sequencing and phenotypic properties test, Strains S was identified as Enterobacter sp.