Chlorination of microcystin-LR in natural water: Kinetics, transformation products, and genotoxicity.

Microcystin-LR (MC-LR), a type of cyanotoxin commonly found in natural water bodies (sources of drinking water), poses a threat to human health due to its high toxicity. It is essential to successfully remove this cyanotoxin from drinking water sources. In this study, chlorine was used to oxidize MC-LR in Milli-Q water (MQ) (control test) and natural water collected from Lake Longhu (LLW) as a drinking water source. The removal efficiency, proposed transformation pathways, and genotoxicity were investigated. In the chlorine dose range investigated (4.0 mg L-1 - 8.0 mg L-1), the apparent second-order rate constants for MC-LR chlorination varied from 21.3 M-1s-1 to 31.9 M-1s-1 in MQ, higher than that in LLW (9.06 M-1s-1 to 17.7 M-1s-1) due to a faster chlorine decay attributed to the water matrix (e.g., natural organic matter) of LLW. Eleven transformation products (TPs) of MC-LR were identified in the two waters. The conjugated diene moieties and benzene ring of Adda moiety (3-amino-9-methoxy-2,6,8-trimethyl-10-phenyldeca-4,6-dienoic acid), and the double bond of Mdha moiety (N-methyldehydroalanine) were the major susceptible reaction sites. Attacking unsaturated bonds by hydroxyl and chlorine radicals to generate monochloro-hydroxy-MC-LR was the primary initial transformation pathway, followed by nucleophilic substitution, dehydration, and cleavage in MC-LR. Chlorine substitution on the benzene ring was also observed. Based on the bacterial reverse-mutation assay (Ames assay), TPs in treated natural water did not induce genotoxicity/mutagenicity. These findings shed light on the role of chlorination in controlling the risk of cyanotoxins in drinking water treatment plants.

A hybrid system for Nickel ions removal from synthesized wastewater using adsorption assisted with electrocoagulation.

The presence of heavy metal ions in water environments has raised significant concerns, necessitating practical solutions for their complete removal. In this study, a combination of adsorption and electrocoagulation (ADS + EC) techniques was introduced as an efficient approach for removing high concentrations of nickel ions (Ni2+) from aqueous solutions, employing low-cost sunflower seed shell biochar (SSSB). The combined techniques demonstrated superior removal efficiency compared to individual methods. The synthesized SSSB was characterized using SEM, FT-IR, XRD, N2-adsorption-desorption isotherms, XPS, and TEM. Batch processes were optimized by investigating pH, adsorbent dosage, initial nickel concentration, electrode effects, and current density. An aluminum (Al) electrode electrocoagulated particles and removed residual Ni2+ after adsorption. Kinetic and isotherm models examined Ni2+ adsorption and electrocoagulation coupling with SSSB-based adsorbent. The results indicated that the kinetic data fit well with a pseudo-second-order model, while the experimental equilibrium adsorption data conformed to a Langmuir isotherm under optimized conditions. The maximum adsorption capacity of the activated sunflower seed shell was determined to be 44.247 mg.g-1. The highest nickel ion removal efficiency of 99.98% was observed at initial pH values of 6.0 for ADS and 4.0 for ADS/EC; initial Ni2+ concentrations of 30.0 mg/L and 1.5 g/L of SSSB; initial current densities of 0.59 mA/cm2 and 1.32 kWh/m3 were also found to be optimal. The mechanisms involved in the removal of Ni2+ from wastewater were also examined in this research. These findings suggest that the adsorption-assisted electrocoagulation technique has a remarkable capacity for the cost-effective removal of heavy metals from various wastewater sources.

The Relationship between the Dietary Inflammatory Index (DII) and Metabolic Syndrome (MetS) in Middle-Aged and Elderly Individuals in the United States.

(1) Background: With the aging demographic shift in society, there is a growing number of middle-aged and elderly individuals affected by metabolic syndrome (MetS), a risk factor contributing to all causes of mortality. Inflammation plays a crucial role in the development of MetS. This study aims to examine the correlation between MetS and pro-inflammatory diets in middle-aged and elderly individuals, utilizing the Dietary Inflammation Index (DII) as a measure. (2) Methods: Data were extracted from the 2007-2016 National Health and Nutrition Examination Survey (NHANES) database for individuals who were 45 years of age or older. The DII was determined for each participant through 24-h dietary recall interviews. The relationship between DII and MetS was assessed using binary logistic regression analysis, and the association between DII and MetS-related indicators was further explored through generalized linear model (GLM) and quantile regression analysis. (3) Results: A total of 3843 middle-aged and elderly individuals were included in the study. After controlling for confounding factors, the highest quartile of DII was associated with a higher risk of MetS (ORQ4:Q1 = 1.339; 95% CI: 1.013, 1.769; p for trend = 0.018). The top DII quartile also increased the risk of reduced HDL-C (ORQ4:Q1 = 1.499; 95% CI: 1.005, 2.234; p for trend = 0.048) and raised FG (ORQ4:Q1 = 1.432; 95% CI: 1.095, 1.873; p for trend = 0.010) compared to the lowest DII quartile. The levels of DII were found to be positively correlated with BMI (ß = 0.258, p = 0.001), FPG (ß = 0.019, p = 0.049), TG (ß = 2.043, p = 0.013), waistline (ß = 0.580, p = 0.002), and negatively correlated with HDL-C (ß = -0.672, p = 0.003). (4) Conclusions: In middle-aged and elderly individuals in the United States, a high DII score has been linked to the presence of MetS, low HDL-C, and hyperglycemia. Therefore, dietary recommendations for the middle-aged and elderly should focus on reducing the DII by choosing foods rich in antioxidants, dietary fiber, and unsaturated fatty acids.

Extensive investigation and beyond the removal of micro-polyvinyl chloride by microalgae to promote environmental health.

Microplastics (MPs) remediation via algae could be a prospective strategy to address MPs pollution concerns. In this study, Chlorella sp. GEEL-08 was exposed to different gradient concentrations ranging from 0 to 200 mg L-1 of polyvinyl chloride (PVC0.2µm). Microalgal growth, total nitrogen (TN), total phosphorus (TP), and cations (Cu, Zn, Na, and K) removal were investigated. The oxidative stress enzymes such as superoxide dismutase (SOD) and malonaldehyde (MDA) were also assessed. The addition of 50 mg L-1 mPVC resulted in the highest growth along with >99% removal of nutrients (TN and TP) and >80% removal of cations. However, the addition of 100-200 mg L-1 mPVC inhibited microalgal growth by 8.8-12.3%. The stress-induced by mPVC was highly observed at 200 mg L-1 mPVC on the 4th d with 70.8 U mgprot-1 and 62.3 nmol mgprot-1 of SOD and MDA, respectively. Fourier-transform infrared spectroscopy (FTIR) spectra confirmed that microalgal biomass retained mPVC. Thermogravimetric analysis/derivative thermogravimetric analysis (TGA/DTG) spectra showed that the organic matter of microalgal biomass attached with mPVC was decomposed faster than control, indicating the possibilities of using this biomass for pyrolysis and the formation of bio-products.

Algae: a frontline photosynthetic organism in the microplastic catastrophe.

Recalcitrancy in microplastics (MPs) contributes to white pollution. Bioremediation can remove MPs and facilitate environmental sustainability. Although recent studies have been conducted on the interaction of algae and MPs, the role of algae in MP removal with the simultaneous implementation of 'omics studies has not yet been discussed. Here, we review the adverse effects of MPs on the environment and possible approaches to remove them from the aquatic environment by using algae. We highlight the mechanism of MP biodegradation, the algal species that have been used, and how these are affected by MPs. We propose that algomics, characterization of biodegrading enzymes, and genetic engineering could be effective strategies for optimizing MP degradation.

Effect of dibutyl phthalate on microalgal growth kinetics, nutrients removal, and stress enzyme activities.

The dibutyl phthalate (DPB) is an emerging plasticizer contaminant that disrupts the biological processes of primary producers, especially phytoplankton. In this study, two microalgal species (Chlorella sp. GEEL-08 and Tetradesmus dimorphus GEEL-04) were exposed to various concentrations of DBP extending from 0 to 100 mg/L. The growth kinetics, N-nitrate, and P-phosphate removal efficiency were assessed. The response enzymes such as malonaldehyde (MDA) and superoxide dismutase (SOD) were also investigated. The results revealed that the Chlorella sp. GEEL-08 at 10 mg/L concentration of DBP exhibited higher growth (0.88 OD680nm) compared to T. dimorphus GEEL-04 (0.80 OD680nm). More than 94% of N and P were removed from culture media by both microalgal species. The DBP (>50 mg/L) significantly exacerbates the growth of both microalgae species and the growth inhibition ratio was in the range of 3.6%-25.9%. The SOD activity and MDA were higher in T. dimorphus culture media than in the culture media of Chlorella sp. The results reflect the hazard and the risk of plasticizers on primary producers in the ecosystem.