A study on chromium accumulation in Labeo rohita in the river Yamuna ecosystem in Mathura-Agra region in Uttar Pradesh, India

The present study revealed the chromium toxicity and its health measures in L. rohita from the Yamuna river at Mathura- Agra region. Samples were taken in triplicate from both sites i.e. Vrindavan (Bihar ghat) and Agra (Renuka Ghat). The study was carried out on Four different organs (i.e. gills, muscles, liver, and kidney) of the fish sample. The sampling was done from Oct 2018 to January 2020. Chromium concentration in different organs of the fish was analyzed by Atomic absorption spectrophotometer(AAS). The average Cr concentration in gills was highest (9.64 mg/l) at the Mathura site followed byAgra sites (7.78 mg/l) for the month of April 2019. The concentration of Cr was highest in samples taken in the month of April 2019 and it was lowest in October 2018. The significantly high Cr concentration values were observed in the Mathura region than the Agra region for both seasons. In all samples, Cr concentration was above the standards stated by WHO except in the Kidney. In the present study, the bioaccumulation factor showed the chromium concentration in the tissues followed the order of gill > liver > muscle > kidney. HPI, MQI, and Pearson’s correlation coefficient analysis were also done in which HPI was observed very high and there was a positive correlation between all the samples. Keywords: Chromium, BCF, HPI, MQI, AAS, Fish Organs

Soil applied glycine betaine with Arbuscular mycorrhizal fungi reduces chromium uptake and ameliorates chromium toxicity by suppressing the oxidative stress in three genetically different Sorghum (Sorghum bicolor L.) cultivars

Background Chromium is the most toxic pollutant that negatively affects a plant’s metabolic activities and yield. It reduces plant growth by influencing the antioxidant defence system’s activities. In the present study, a completely randomized block design experiment with three plants/pot in three replication was conducted on three varieties of sorghum viz. SSG 59–3, HJ 513 (multi-cut) and HJ 541 (single-cut) for amelioration of chromium toxicity (2 & 4 ppm) by exogenous application of GB (50 & 100 mM) with and without AMF in soil. The ameliorative effects were tested at two growth stages viz. vegetative (35 DAS) and grain filling (95 DAS), in terms of Cr uptake, grain yield, antioxidative defence system parameters (viz. enzymes – SOD, APX, CAT, GR, POX and metabolites – proline, glutathione, ascorbate, β-carotene) and indices of oxidative stress parameters (viz. PPO, H2O2, and MDA). Results The results delineated that Cr uptake and indices of oxidative stress were increased with increasing concentration of Cr stress in all the varieties (HJ 541, HJ513 & SSG 59–3) at both the growth stages (35 & 95 DAS). At higher concentration (4 ppm), Cr stress decreased the grain yield (45–50%) as compared with controls. Polyphenoloxidase activity, MDA and H2O2 content increased at both growth stages in all the varieties. However, antioxidative enzymes and metabolite activities increased due to Cr stress but this increase was not sufficient to counteract with ROS generated under Cr stress which was enhanced on the application of AMF and GB either individually or in combination (spiked in soil). It decreased the indices of oxidative stress and ameliorated the Cr toxicity and increased grain yield (65–70%) in all the varieties. Conclusions Both GB and AMF improved the antioxidative activities and stress tolerance capacity of the plant. Glycine betaine at both 50 and 100 mM level, significantly ameliorated Cr toxicity. However, AMF concomitantly with GB further boosts up the amelioration behaviour of the plant against Cr toxicity, at both growth stages in all the varieties. The combination of 100 mM GB with 10 g AMF was observed most effective among all the treatments. Among the varieties, SSG 59–3 had the lowest chromium uptake, indices of oxidative stress, and highest antioxidative system’s activity as compared to HJ 513 followed by HJ 541 variety. Thus AMF and GB either individually or in combination may be used to maintain plant yield attributes under Cr toxicity.

Toxicity and teratogenicity in zebrafish Danio rerio embryos exposed to chromium

Chromium (Cr) is an element present in nature in mineral form. It has a dual effect, both as an essential micronutrient and a carcinogenic agent depending on its chemical form and concentration. It is present in various environmental matrices such as water, soil, and air, coming from natural and anthropogenic sources, and causes harmful effects on biota, ecosystems, and even human beings. This study's objective was to evaluate chromium toxicity and teratogenicity in zebrafish embryos of Danio rerio exposed to chromium through the D. rerio teratology assay (DarTA) test by evaluating spine malformations. To this end, the chromium toxicity curve was calculated from zebrafish embryos exposed to potassium dichromate (K2Cr2O7), and the probit test was used to establish the mean lethal concentration (LC50) and three subtoxic concentrations LC25, LC12.5, and LC6.25 to evaluate the teratogenicity. The results showed that potassium dichromate was statistically positive for the teratogenic effect at the three highest concentrations evaluated. Potassium dichromate exposure causes abnormal embryonic development and teratogenic effects, including severe heart defects in zebrafish embryos. Therefore, we conclude that potassium dichromate is toxic to the zebrafish developmental stages. The finding that potassium dichromate is teratogenic in zebrafish embryos suggests that this metal should be tested and evaluate potential risk in mammalian systems.