Quantifying and managing regional greenhouse gas emissions：Waste sector of Daejeon, Korea

A credible accounting of national and regional inventories for the greenhouse gas （GHG） reduction has emerged as one of the most significant current discussions. This article assessed the regional GHG emissions by three categories of the waste sector in Daejeon Metropolitan City （DMC）, Korea, examined the potential for DMC to reduce GHG emission, and discussed the methodology modified from Intergovernmental Panel on Climate Change and Korea national guidelines. During the last five years, DMC＇s overall GHG emissions were 239 thousand tons C02 eq./year from eleven public environmental infrastructure facilities, with a population of 1.52 million. Of the three categories, solid waste treatment/disposal contributes 68%, whilst wastewater treatment and others contribute 22% and 10% respectively. Among GHG unit emissions per ton of waste treatment, the biggest contributor was waste incineration of 694 kg CO2 eq./ton, followed by waste disposal of 483 kg CO2 eq./ton, biological treatment of solid waste of 209 kg CO2 eq./ton, wastewater treatment of 0.241 kg CO2 eq./m3, and public water supplies of 0.067 kg CO2 eq./m3. Furthermore, it is suggested that the potential in reducing GHG emissions from landfill process can be as high as 47.5% by increasing landfill gas recovery up to 50%. Therefore, it is apparent that reduction strategies for the main contributors of GHG emissions should take precedence over minor contributors and lead to the best practice for managing GHGs abatement.     

Fetal methylmercury exposure as measured by cord blood mercury concentrations in a mother-infant cohort in Hong Kong

This study was designed to examine newborn infants in Hong Kong prenatally exposed to levels of methylmercury considered to increase risk of neurotoxic effects and to examine subject characteristics that modify the degree of prenatal mercury exposure. Mercury concentrations in 1057 sets of maternal and cord blood samples and 96 randomly selected maternal hair samples were measured. Subject characteristics were measured or collected by questionnaire. Of the 1057 cord blood samples collected only 21.6% had mercury concentrations less than 29 nmol/L (5.8 micro g/L). Median maternal hair mercury concentration was 1.7 ppm. The geometric mean cord to maternal blood mercury ratio was 1.79 to 1. Increasing maternal fish consumption and maternal age were found to be associated with increased cord blood mercury concentrations. Marine fish consumption increased cord blood mercury concentrations more than freshwater fish (5.09%/kg vs 2.86%/kg). Female babies, maternal alcohol consumption and increasing maternal height were associated with decreased cord blood mercury concentrations. Pregnant women in Hong Kong consume large amounts of fish and as a result, most of their offspring have been prenatally exposed to moderately high levels of mercury. In this population, pregnant women should choose freshwater over marine fish and limit fish consumption.     

Impact of ozone assisted ultrasonication pre-treatment on anaerobic digestibility of sewage sludge

Impact of ultrasonication(ULS) and ultrasonication–ozonation(ULS-Ozone) pre-treatment on the anaerobic digestibility of sewage sludge was investigated with semi-continuous anaerobic reactors at solid retention time(SRT) of 10 and 20 days. The control, ULS and ULS-Ozone reactors produced 256, 309 and 348 m L biogas/g CODfedand the volatile solid(VS) removals were 35.6%, 38.3% and 42.1%, respectively at SRT of 10 days. At SRT of20 days, the biogas yields reached 313, 337 and 393 m L biogas/g CODfedand the VS removal rates were 37.3%, 40.9% and 45.3% in the control, ULS and ULS-Ozone reactors, respectively.ULS-Ozone pre-treatment increased the residual organic amount in the digested sludge.These soluble residual organics were found to contain macromolecules with molecular weights(MW) larger than 500 k Da and smaller polymeric products with MW around 19.4and 7.7 k Da. These compounds were further characterized to be humic acid-like substances with fluorescent spectroscopy analysis.     

Ashes to ashes,and dust to dust: Is scattering garden the sustainable destination for cremated ashes?

Environmental Science and Pollution Research - Cremation is commonly practiced around the world because it requires small space for the disposal of ashes. Among various options for ash disposal,...     

Carbon dioxide electroreduction into formic acid and ethylene: a review

Environmental Chemistry Letters - Climate change damage induced by growing carbon dioxide (CO2) emissions has rapidly fostered research on capturing, utilizing, and converting CO2 into valuable C1...     

An Enzymatic Method for Harvesting Functional Melanosomes after Keratin Extraction: Maximizing Resource Recovery from Human Hair

Journal of Polymers and the Environment - Hair contains about 80% keratins and 1–3% melanin packaged in melanosomes. Both of these are high-value and functional raw materials that have...     

Chronic exposure of arsenic via drinking water and its adverse health impacts on humans

Worldwide chronic arsenic (As) toxicity has become a human health threat. Arsenic exposure to humans mainly occurs from the ingestion of As contaminated water and food. This communication presents a review of current research conducted on the adverse health effects on humans exposed to As-contaminated water. Chronic exposure of As via drinking water causes various types of skin lesions such as melanosis, leucomelanosis, and keratosis. Other manifestations include neurological effects, obstetric problems, high blood pressure, diabetes mellitus, diseases of the respiratory system and of blood vessels including cardiovascular, and cancers typically involving the skin, lung, and bladder. The skin seems to be quite susceptible to the effects of As. Arsenic-induced skin lesions seem to be the most common and initial symptoms of arsenicosis. More systematic studies are needed to determine the link between As exposure and its related cancer and noncancer end points.     

Sustainable production in circular economy: aerogel upscaling production

Environmental Science and Pollution Research -     

Accelerated sunlight photocatalysis through improved electron mobility between g-C3N4 and BiPO4 nanomaterial

Herein, we report a detailed study on creating heterojunction between graphitic carbon nitride (g-C₃N₄) and bismuth phosphate (BiPO₄), enhancing the unpaired free electron mobility. This leads to an accelerated photocatalysis of 2,4-dichlorophenols (2,4-DCPs) under sunlight irradiation. The heterojunction formation was efficaciously conducted via a modest thermal deposition technique. The function of g-C₃N₄ plays a significant role in generating free electrons under sunlight irradiation. Together, the generated electrons at the g-C₃N₄ conduction band (CB) are transferred and trapped by the BiPO₄ to form active superoxide anion radicals (?O₂^?). These active radicals will be accountable for the photodegradation of 2,4-DCPs. The synthesized composite characteristics were methodically examined through several chemical and physical studies. Due to the inimitable features of both g-C₃N₄ and BiPO₄, its heterojunction formation, 2.5wt% BiPO₄/g-C₃N₄ achieved complete 2,4-DCP removal (100%) in 90 min under sunlight irradiation. This is due to the presence of g-C₃N₄ that enhanced electron mobility through the formation of heterojunctions that lengthens the electron-hole pairs’ lifetime and maximizes the entire solar spectrum absorption to generate active electrons at the g-C₃N₄ conduction band. Thus, this formation significantly draws the attention for future environmental remediation, especially in enhancing the entire solar spectrum’s harvesting.

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Recovery of precious metals from e-wastes through conventional and phytoremediation treatment methods: a review and prediction

Journal of Material Cycles and Waste Management - E-waste, also known as waste from electrical and electronic equipment, is a solid waste that accumulates quickly due to high demand driven by the...