Heavy metals in contaminated soil: source, accumulation, health risk and remediation process

Heavy metals contamination of soil is an issue of global concern that ultimately results in toxicity and diseases in humans and animals through consumption of food crops from contaminated soil. The toxic effects of these metals, even though they do not have any biological role, remain present in some or the other form harmful for the human body and its proper functioning. Heavy metals in the soil refers to some significant heavy metals of biological toxicity, including Cobalt (Co), Cadmium (Cd), Lead (Pb), Chromium (Cr), and Arsenic (As) etc. With the development of the global economy, both type and content of heavy metals in the soil caused by indiscriminate use for human purposes has altered their geochemical cycles and biochemical balance. There are many known sources of harmful metals, including the earth, which releases them into food, air, and water, and anthropogenic activities, such as the application of fertilizer in agriculture, the use of pesticides and herbicides, and irrigation. Other sources are automobile emissions, paints, cigarette smoking, industries, and sewage and waste disposal. This review gives details about some heavy metals their toxicity, bioaccumulation, biodegradation, mobility and solubility in contaminated soil along with their health effects. Remediation of heavy metal in contaminated soils is necessary to reduce the associated risks, make the available soil safe for agricultural production, enhance food security and scale down land tenure problems arising from changes in the land use pattern the review recommends regular monitoring of heavy metals in soil, vegetables and foodstuffs to prevent excessive accrual in food chain.

Comprehensive Automobile Research System (CARS) – a Python-based Automobile Emissions Inventory Model

The Comprehensive Automobile Research System (CARS) is an open-source python-based automobile emissions inventory model designed to efficiently estimate high quality emissions from motor-vehicle emission sources. It can estimate the criteria air pollutants, greenhouse gases, and air toxics in various temporal resolutions at the national, state, county, and any spatial resolution based on the spatiotemporal resolutions of input datasets. The CARS is designed to utilize the local vehicle activity database, such as vehicle travel distance, road link-level network Geographic Information System (GIS) information, and vehicle-specific average speed by road type, to generate a temporally and spatially enhanced automobile emissions inventory for policymakers, stakeholders, and the air quality modeling community. The CARS model adopted the European Environment Agency's (EEA) onroad automobile emissions calculation methodologies to estimate the hot exhaust, cold start, and evaporative emissions from onroad automobile sources. It can optionally utilize road link-specific average speed distribution (ASD) inputs to reflect more realistic vehicle speed variations by road type than a road-specific single averaged speed approach. Also, utilizing high-resolution road GIS data allows the CARS to estimate the road link-level emissions to improve the inventory's spatial resolution. When we compared the official 2015 national mobile emissions from Korea's Clean Air Policy Support System (CAPSS) against the ones estimated by the CARS, there is a moderate increase of VOC (33 %), CO (52 %), and fine particulate matter (PM2.5) (15 %) emissions while NOx and SOx are reduced by 24 % and 17 % in the CARS estimates. The main differences are driven by the usage of different vehicle activities and the incorporation of road-specific ASD, which plays a critical role in hot exhaust emission estimates but wasn’t implemented in Korea’s CAPSS mobile emissions inventory. While 52% of vehicles use gasoline fuel and 35 % use diesel, gasoline vehicles only contribute 7.7 % of total NOx emissions while diesel vehicles contribute 85.3 %. But for VOC emissions, gasoline vehicles contribute 52.1 % while diesel vehicles are limited to 23 %. While diesel buses are only 0.3 % of vehicles, each vehicle has the largest contribution to NOx emissions (8.51 % of NOx total) due to its longest daily VKT. For VOC, CNG buses are the largest contributor with 19.5 % of total VOC emissions. It indicates that the CNG bus is better for the rural area while the diesel bus is better applicable for the urban area for a better ozone control strategy because the rural area is usually NOx limited for ozone formation and urban area is VOC limited region. For primary PM2.5, more than 98.5 % is from diesel vehicles. The CARS model's in-depth analysis feature can assist government policymakers and stakeholders develop the best emission abatement strategies.

GREENWASHING BEHAVIOURS: CAUSES, TAXONOMY AND CONSEQUENCES BASED ON A SYSTEMATIC LITERATURE REVIEW

This study used the systematic review methodology to examine peer-reviewed journal articles published in the Web of Science, ScienceDirect, Springer and Emerald Insight during the 2000–2020 period to analyse greenwashing. In an open market, the behaviours of state-owned enterprises (SOEs), private firms and multinational corporations (MNCs) pose an implicit greenwashing threat. Our focal point is to analyse corporate greenwashing in MNCs in host emerging markets, particularly in Asia, for two reasons. First, reports of greenwashing have increased around the world since Volkswagen was revealed to have falsified automobile emissions data. Second, MNCs play an important role in expanding market size and their behaviour is increasingly unpredictable. The analysis shows that MNCs tend to engage in greenwashing immediately after doing business in host emerging markets characterised by restricted regulations, clear market opportunities and low competitive pressure. When greenwashing occurs, it will harm the interests of not only consumers, but also society as a whole, despite offering significant benefits to existing stakeholders. In this case, the authorities should implement regulations to confront MNCs before attracting them, which should be enforced in practice.

Modifying Exhaust After-Treatment Device for Complying with Future Emission Norms

Day to day increase in air pollution is one of the serious issues nowadays. One of the main contributors is automobile emissions. It contains gases like carbon dioxide, carbon monoxide, hydrocarbon, nitrogen oxides, and particular matters. In order to address such issues, this paper is focused on the reduction of emissions by modifying the design of an exhaust after-treatment device. The analysis is carried out on a 4-stroke single-cylinder 149cc FZ-S BS4 bike two-wheeler gasoline engine.CO and HC emissions absorbed by an aqueous solution having different TDS of aqua 90ppm RO water, 1000ppm Municipality water, and 10000ppm seawater. Such aqueous solution contains calcium powder and activated carbon in 10:0.5:0.5, 10:1:1 and 10:2:2 in proportion respectively. An optimum solution derived which having a mixture of 10:1:1 proportion having 10000ppm seawater is derived which shows reduction in CO by 50% and HC emission by 40% as compare conventional muffler exhaust emission. The IoT device is used with the MQ-7 sensor to measure CO emission from a modified device and data obtained are compared with PUC (Pollution under control) certified center. This research is to optimize emission from the existing gasoline engine, from April 2017 BS4 is implemented in INDIA nationwide & BS6 will be going to implement by 2020. From April 2017 manufacturer are not allowed to build new engines below BS4 standard but customer those who are having an older version of engines are not having any effect of BS4 & their engines are still emitting more pollution than the current emission norms. More than 100 million of twowheeler engines were sold in between Feb‘06- March’17. This study aims to provide a solution for such engines not from the manufacturer side but from the consumer side to upgrade their vehicle to satisfy future emission norms so that human health will be less affected by such emissions.

Seasonal Control of Water-Soluble Inorganic Ions in PM2.5 from Nanning, a Subtropical Monsoon Climate City in Southwestern China

In this study, we measured the daily water-soluble inorganic ions (WSIIs) concentration (including SO42−, NO3−, NH4+, Ca2+, K+, Cl−, Na+, Mg2+, and F−) of PM2.5 (particulate matter with a diameter smaller than 2.5 μm) throughout the year in Nanning (a typical subtropical monsoon climate city in southwestern China) to explore the influence of seasonal climate change on the properties of PM2.5 pollution. This suggested that SO42−, NO3−, and NH4+ were the main component of WSIIs in Nanning. Secondary inorganic ions from fossil fuel combustion, agricultural activities, and automobile emissions were the main contributors to PM2.5, contributing more than 60% to PM2.5. Compared with the wet season, the contributions of different sources increased in the dry season (including pollution days); of these sources, automobile emissions and coal combustion emissions increased the most (about nine times and seven times, respectively). Seasonal weather and climate change affected the concentration level of WSIIs. During the wet season, higher temperatures and abundant rainfalls contributed to the volatilization and removal of WSIIs in PM2.5, while in the dry season and on pollution days, lower temperatures and less precipitation, higher emissions, and poor diffusion conditions contributed to the accumulation of WSIIs in PM2.5. NH4HSO4, (NH4)2SO4 and NH4NO3 were the main chemical forms of secondary inorganic ions. Sufficient NH3, intense solar radiation, and moist particulate matter surface promoted the formation of secondary inorganic ions. The higher temperature contributed to the volatilization of secondary inorganic ions.

Modeling and Analysis of Noise Barrier Shape Effects on Highway Automobiles Emission Dispersion

Noise barriers are common configurations along highways. They are originally designed to impede and absorb the noise from vehicles on highways. Recent research has suggested that noise barriers have significant impacts on near-road automobile emissions. Highway noise barriers can make a great difference on the dispersion of air pollutants on and downstream of highway than those with non-barriers features. Certain shaped noise barriers have better performance on reduction noise than others, but the noise barrier shape effects on emission dispersion are still not clear. In this paper a 3-dimensional computational fluid dynamics (CFD) model has been developed to simulate the shape effects on highway downstream and nearby region emission dispersion. The realizable k-ε turbulence model was adopted to simulate the turbulent flow caused by fast moving vehicles on highway. A non-reaction species transport model was applied to simulate emission dispersion. The model was first used to simulate rectangular shaped noise barriers effect on highway emission dispersion. Results were compared with the data from literature, and good agreements were observed. Further, simulations were conducted to reveal the noise barrier shape as well as various height effects on emission dispersion on highway and nearby regions.

California Greenin'

Over the course of its 150-year history, California has successfully protected its scenic wilderness areas, restricted coastal oil drilling, regulated automobile emissions, preserved coastal access, improved energy efficiency, and, most recently, addressed global climate change. How has this state, more than any other, enacted so many innovative and stringent environmental regulations over such a long period of time? This book shows why the Golden State has been at the forefront in setting new environmental standards, often leading the rest of the nation. From the establishment of Yosemite, America's first protected wilderness, and the prohibition of dumping gold-mining debris in the nineteenth century to sweeping climate-change legislation in the twenty-first, the book traces California's remarkable environmental policy trajectory. It explains that this pathbreaking role developed because California had more to lose from environmental deterioration and more to gain from preserving its stunning natural geography. As a result, citizens and civic groups effectively mobilized to protect and restore their state's natural beauty and, importantly, were often backed both by business interests and by strong regulatory authorities. Business support for environmental regulation in California reveals that strict standards are not only compatible with economic growth but can also contribute to it. The book also examines areas where California has fallen short, particularly in water management and the state's dependence on automobile transportation.

Modeling and Analysis of the Effects of Noise Barrier Shape and Inflow Conditions on Highway Automobiles Emission Dispersion

Recent research has suggested that noise barriers have significant impacts on near-road automobile emissions reduction. T-shaped noise barriers have better performance on reducing noise than others, however, their effects on automobile emissions reduction are not clear. In this research, commercial software ANSYS®Fluent 19.2 (Ansys Inc., Canonsburg, PA, USA) was applied to simulate the noise barrier shape and different inflow wind shear condition effects on highway automobiles emission dispersion. Various Reynolds Averaged Navier-Stokes (RANS) models were tested. The realizable k-ε turbulence model was selected to simulate the turbulent flow caused by fast moving vehicles on highway based on the comparison results. A non-reacting species transport model was applied to simulate emission dispersion. Results showed that the T-shaped barrier was able to help reduce highway automobiles emission concentration in downstream areas more than the rectangular barrier. An optimized range of the T-shape was proposed; under the inflow condition without wind shear, the noise barrier shape effects on automobiles emission reduction were not significant.