Environmental Chemistry and Ecotoxicology最新文献

The presence of antibiotic resistance genes (ARGs) and antibiotic-resistant bacteria (ARB) in the environment is of great concern to human health. This study developed a new combination of high-frequency electromagnetic field (HEMF) and low-dosage chlorine disinfection to reduce the abundance of extracellular ARG (eARG) sul2 and intracellular ARG (iARG) adeF. The removal efficiencies of sul2 and adeF from sulfamethoxazole- and multidrug-resistant Acinetobacter junii were measured by quantitative PCR (qPCR). Compared to chlorine disinfection alone, the combination of HEMF treatment exhibited significantly improved ARG removal efficiency. The highest removal efficiencies of sul2 and adeF under the combination were 75.7% and 91.4%, respectively. Treatment time and the dosage of chlorine played pivotal roles in the removal efficiency of ARGs via HEMF treatment and chlorine disinfection, respectively. Importantly, a combination of low-dose chlorine with HEMF treatment could serve as a viable alternative to high-dose chlorine disinfection. This work offers essential process parameters for optimizing the elimination of iARGs and eARGs and presents a viable solution for addressing the issue of ARG contamination.

Sukinda Valley of Jajpur district, Odisha contributes about 98% of India's total chromite reserves with about 334 million tons annual production rate globally, which plays a colossal role to strengthen the economy of our country and leads to sustainable development. The consequences related to chromite mining and excessive production of chromium have entitled this valley a “Valley of Despair”. A far-reaching production of different forms of chromite ore has bowed this area into a contamination-prone region due to the deposition of an unacceptable amount of chromium in the soil, sediment, groundwater and air of Sukinda. Around 1.8 lakh mining workers and nearby village dwellers are getting affected due to the presence of the forbidden amount of chromium ions. The foremost roots of exposure by humans are inhalation of contaminated air, accidental ingestion and contact absorption by skin. In the environment, chromium occurs in different forms and its level of toxicity also varies in each state. Chromium in its hexavalent form is bio-leachable and water-soluble. Thereby easily contaminates the water body which in turn becomes accessible to human beings and reacts with the cellular components. Long-term exposure to the human body may result in initiating several serious diseases like microcytic anaemia, mitochondrial and DNA damage of blood cells which in turn induces carcinogenicity, occupational asthma, airway hypersensitivity, nose, eye and skin irritation etc. The repercussion of chromium contamination at the terrestrial level is not endemic but also invades other sectors of the natural environment via the food chain and other means of transportation. Numerous on-going studies are yet to be carried out for the reduction and remediation of chromium from the contaminated environment. Nevertheless, this issue is worsening at a rapid rate making it difficult to tackle. The chromite mining activities in Sukinda Valley are creating difficulties for the livelihood as well as for the natural environment due to the discharge of massive amount of contaminants. The issue related to the chromium contamination is gigantic and needs urgent management and control strategies. Therefore, the present review focuses on the present scenario to combat deleterious effects initiated as a result of long-term exposure to metallic pollutant, Hexavalent Chromium [Cr(VI)] on the natural environment as well as on human health specifically on the health of mining workers and villagers residing near the Sukinda Valley, Odisha.

The increase in the level of iron concentration in drinking water due to natural and anthropogenic activities has become a major problem imposing a severe risk to human wellness. Mining and associated activities have qualitative and quantitative effects on the water regimes in and around the mines. People residing in the mining areas of Odisha, India, confronted a typical problem of iron contamination in water. Almost 60% of the surface water and 50% of the drinking water constitutes iron ions more than the permissible limit established by World Health Organization (W.H·O) i.e. 0.3 mg/L has been noted. Excessive iron accumulation may cause severe health problems such as hemochromatosis, diseases related to the heart and central nervous system, cirrhosis of the liver, diabetes, nausea, etc. Available literature has been incorporated on iron remediation by adsorption technology. This technology has been widely accepted because it offers economic and environmental benefits such as low cost, availability, profitability, ease of operation, and high removal efficacy. Thus the feasibility of activated carbon prepared from various agro-wastes for eradication of iron ions by batch and fixed-bed adsorption has been critically reviewed in this paper.

Per- and poly-fluoroalkyl substances (PFAS) have raised global concerns regarding soil contamination and the subsequent adverse effects on soil organisms. PFOS, PFOA, and PFHxS are among the commonly detected PFAS in the environment with much attention directed to PFOS and PFOA and minimal information available on the toxicity of PFHxS for ecotoxicological assessments. Therefore, this study focuses on the toxic potential of PFHxS to soil biota. The effects of PFHxS to microbial processes and earthworms were assessed in a wide range of concentration (0–1000 mg/kg) in soil to define the safe concentration. The soil enzyme activities (dehydrogenase activity and soil respiration rate) were significantly reduced after exposure to PFHxS at concentrations exceeding 100 mg/kg. The bacterial community suffered more than the fungal community upon PFHxS exposure. Bacterial diversity and richness were inhibited due to PFHxS exposure. However, at taxonomic level, growth of some bacterial phyla was stimulated (e.g., Actinobacteria) while others were inhibited (e.g., Acidobacteria). Earthworm survival was also significantly affected at concentrations exceeding 100 mg/kg. Our findings showed that exposure to PFHxS negatively affects the soil microbial processes and earthworm survival, potentially jeopardising their functions.

Brazil boasts of large hydrographic basins, numerous lentic environments, and an extensive coastal region. These aquatic environments are susceptible to the presence of metals originated from both natural and anthropic activities, so methods to assess the ecological risk to these environments, such as the Biotic Ligand Model (BLM), are of immense value. This study comprises a systematic review of selected articles published from 2008 to 2020 to answer the following question: Why is BLM so scarcely applied in Brazil? Data was compiled to identify the origin, tests, methods, journal impact factor, and year of publication of all included papers retrieved from the Scopus database. The BLM was shown as efficient in predicting metal toxicity in both seawater and freshwater considering both organisms and environmental factors (speciation in water). Copper, cadmium, nickel, zinc, lead, and silver were the most reported throughout the years, with copper ranking first, reported in 133 publications. Other metals were also reported, but in a lower number of published papers. Daphnia magna was the most evaluated test organism. Several BLM papers were published in relatively high impact factor journals (4,93 on average), reinforcing the importance of the subject. Brazil ranked 7th in BLM publishing, participating with 4% of the published articles from the retrieved total, with most studies published by research groups in the South region. Some recommendations are raised in this review, such as the need for more interactions between research groups in Brazil, deeper connectivity between legislation and BLM studies and further BLM applications in the country, as each waterbody displays its own specific particularities.

In the present study, hazardous heavy metal ion hexavalent chromium (Cr(VI)) was removed from aqueous solution by using Indion GS-300 (IGS-300), strong base anion exchange resin. The process parameters for the removal of Cr(VI) were optimized using response surface methodology (RSM) approach. Procured resin was analyzed by various techniques like FTIR, and FESEM associated with elemental analysis which provided functional groups and surface structure of the adsorbents. Various batch adsorption experiments were conducted by varying parameters such as Cr(VI) concentrations from 5 mg/L to 45 mg/L, 2 to 10 pH, IGS-300 resin dosage between 0.38 and 1.88 g/L, and temperature of 20–40 °C with 90 min fixed contact time. Fixed time was determined from preliminary study of the present work. The maximum adsorption capacity of IGS-300 resin was found 294.11 mg/g and 98.20% of removal achieved with optimum conditions of 4 pH, 1.50 g/L adsorbent dosage, 15 mg/L Cr(VI) concentration and 35 °C temperature. The experimental data was found with best fitted Freundlich Isotherm and pseudo second order kinetic model. Regeneration study was also done on the adsorbed resins using different solution includes water, 0.1 M HCl, and 0.1 M NaOH. Up to 3 cycles of 0.1 M NaOH treatment, resin showed >50% Cr(VI) removal in aqueous solution whereas water and HCl were found less effective on third cycle. Therefore, this study found that IGS-300 resin is more efficient adsorbent for the removal of Cr(VI) from aqueous solutions and possessing highly significant regeneration capacity.

The prevalent occurrence of organophosphate pesticides in the environment is widely accompanied by severe adverse impacts on environmental matrices and humans owing to their bioaccumulation in the food chain or direct exposure. Despite the intervention of regulatory agencies on the levels of pesticide residues, studies have shown that these pesticide congeners are still present in human blood serum and urine as well as soil, sediments, water, and air. This, therefore, requires the adoption of both conventional and newly developed methods for the total mitigation of pesticides in environmental matrices. The ubiquitous nature of this group of xenobiotics in both environmental and biological matrices, particularly at alarming concentrations as reported in the reviewed studies, is responsible for its attendant adverse health and ecological impacts. Based on available evidence, the predominant source of organophosphate pesticides in the environment is agricultural application. Although this class of persistent organic pollutants is relatively less persistent in the environment than their organochlorine counterparts, nevertheless, their neurotoxic effects on humans cannot be undermined. Adequate measures must be taken to regulate the storage and usage of these pesticides on farmlands. It is also recommended that more eco-friendly and sustainable approaches should be developed to circumvent the distressing effects of organophosphate pesticides. In this review article, special attention is given to the occurrence of these pesticide residues in biological and environmental matrices. This article comprehensively discusses recent advances in the remediation of organophosphate pesticides whilst exploring future perspectives for these remedial approaches.

A detailed study has been carried out to develop a process which can yield highly porous activated carbons from lignocellulosic biomasses and check the antimicrobial properties by doping with metals such as Cu and Zn. According to the availability of the waste biomasses in the Indian subcontinent especially in the North-Eastern region which is considered a biomass hotpot, activated carbon samples were prepared using rubber wood sawdust, ramie fibre and areca husk as they are available in plenty. The activated carbons were prepared using a modified thermo-chemical treatment at different temperatures and activation time to increase the surface area of the activated carbon samples which was found to be in the range of 346–1998 m²/g. The activated carbon samples were found to have thereby exhibited good antimicrobial activity against E.coli on the incorporation of suitable metals such as Cu and Zn into the highly porous carbon matrix. The activated carbon samples which were prepared at 700 °C using rubber wood sawdust and areca fibres reported a better bactericidal effect ranging between 75 and 93.5% against the carbon dosages ranging between 10 and 20 g/L of water samples containing E. coli. The antimicrobial killings were confirmed through the minimum inhibitory concentration (MIC) process by using UV Visible Spectroscopy. Various analytical methods such as DSC, FTIR, BET and FESEM-EDX etc. were applied to describe the properties of the samples. This study will give more information about the utilization of activated carbons for drinking water purification purposes.

Landfill area is one of developing countries' most common anthropogenically contaminated sites. The pressure of urbanization has led to increased waste generation in major cities, commonly deposited in landfills; hence, heavy metals contaminations are closer to the human environment than ever. The study assessed the environmental risk of Arsenic (As), Cadmium (Cd), Zinc (Zn), Manganese (Mn), Copper (Cu), Colbat (Co), Cranium (Cr), Nickel (Ni), and Lead (Pb) in an abandoned landfill system and health-related risk using United State Environmental Protection Agency model. The Concentration of the elements descended as follows; Mn > Zn > Cr > Pb > Cu > Ni > Co > As > Cd and exceeded the WHO permissible limit. The Enrichment factor (EF) and potential ecological risk (ER) indicated no enrichment and low risk for all the elements except Cd (3.67, 426), with moderate enrichment and very high ecological risk. The hazard index (HI) value of the elements indicated no significant risk of non-carcinogenic effect for both Adults and Children except for Mn in Children with a value of 1.69 × 10⁰; however, the HI value of the elements descended as; Co > Mn > Zn > As > Cd > Cu > Pb > Ni > Cr for adult and Mn > Cd > Co > Cr > As > Zn > Pb > Cu > Ni for children. The total carcinogenic risk (TCR) value of the toxic metals descended as Ni > Cd > Cr > As > Pb for both adults and Children, while the metals showed no carcinogenic to acceptable risk to humans. The Principal Component Analysis (PCA) indicated that the metals have similar sources and distribution which could be both lithogenic and anthropogenic influenced. Engaging the environment through sustainable practices will ensure efficient waste disposal and management.