Evaluation of Cadmium Bioaccumulation-Related Physiological Effects in Salvinia biloba: An Insight towards Its Use as Pollutant Bioindicator in Water Reservoirs

Free-living macrophytes play an important role in the health of aquatic ecosystems. Therefore, the use of aquatic plants as metal biomonitors may be a suitable tool for the management of freshwater reservoirs. Hence, in this study, we assessed the effects of cadmium (Cd) in Salvinia biloba specimens collected from the Middle Paraná River during a 10-day experiment employing artificially contaminated water (100 μM Cd). S. biloba demonstrated a great ability for Cd bioaccumulation in both the root-like modified fronds (named “roots”) and the aerial leaf-like fronds (named “leaves”) of the plants. Additionally, Cd toxicity was determined by the quantification of photosynthetic pigments (chlorophylls a and b, and carotenoids), flavonoids, and soluble carbohydrate contents in S. biloba over time (1, 3, 5, 7, and 10 days). In general, deterioration was more pronounced in leaves than in roots, suggesting a greater implication of the former in long-term Cd sequestration in S. biloba. Deleterious effects in the appraised parameters were well correlated with the total amount of Cd accumulated in the leaves, and with the qualitative changes observed in the plants’ phenotype during the 10-day metal exposure assay. The flavonoids and carotenoids in leaves were highly affected by low Cd levels followed by root carbohydrates. In contrast, chlorophylls and root flavonoids were the least impacted physiological parameters. Therefore, our results demonstrate that S. biloba displays dissimilar organ-linked physiological responses to counteract Cd phytotoxicity and that these responses are also time-dependent. Though further research is needed, our work suggests that easy-handled physiological data obtained from autochthonous free-floating S. biloba specimens may be used as a valuable tool for metal-polluted water biomonitoring.

Study of Cadmium Bioaccumulation in Perna viridis through Food Pathway and Its Decontamination

Seafood can be contaminated by heavy metals that contained in seawater and the source of food that marine biotas eats. Cadmium is one of the contaminants found in the marine environment. Bioaccumulation studies via foood pathway were complement previous studies through the seawater pathway. This study also made an effort to biologically decontaminate cadmium using acetic acid and citric acid. The experimental results showed the total bioaccumulation ability of Cd by Perna viridis was 74.01. Cd decontamination which accumulates in the Perna viridis decreases the level up to 21%

Biological Responses to Cadmium Stress in Liverwort Conocephalum conicum (Marchantiales)

Oxidative damage (production and localization of reactive oxygen species) and related response mechanisms (activity of antioxidant enzymes), and induction of Heat Shock Protein 70 expression, have been studied in the toxi-tolerant liverwort Conocephalum conicum (Marchantiales) in response to cadmium stress using two concentrations (36 and 360 µM CdCl2). Cadmium dose-dependent production of reactive oxygen species (ROS) and related activity of antioxidant enzymes was observed. The expression level of heat shock protein (Hsp)70, instead, was higher at 36 µM CdCl2 in comparison with the value obtained after exposure to 360 µM CdCl2, suggesting a possible inhibition of the expression of this stress gene at higher cadmium exposure doses. Biological responses were related to cadmium bioaccumulation. Since C. conicum was able to respond to cadmium stress by modifying biological parameters, we discuss the data considering the possibility of using these biological changes as biomarkers of cadmium pollution.

Effect of Swine Bone Powder for Reduce Cadmium Uptake by Rice

The effect of swine bone powder application on bioavailability of Cd in contaminated soil from Tak Province, Thailand were conducted. The bioavailability of Cd was investigated in term of the uptake by rice plant (Oryza sativa L.) in green house at three different application rates of swine bone powder amended soil, including 5, 10 and 15%, respectively. The result demonstrated that the efficiency of cadmium uptake in Khao Dawk Mali 105 rice were in range 0.18-0.20 % and the 5% swine bone amended soil had a positive effect on promoting plant growth and seed yield. Cd concentration in both of shoot and roots decreased with increasing the swine bone application rates. Cadmium bioaccumulation in plant root to soil and translocation factor from root to shoot was less than one. The results indicated that swine bone powder-amended soil could be an alternative and cost-effective method to support plant growth and decrease Cd mobility in soil.