Nitrogen mineralization in O horizon soils during 27 years of nitrogen enrichment at the Bear Brook Watershed in Maine,USA

Chronic elevated nitrogen (N) deposition has altered the N status of temperate forests, with significant implications for ecosystem function. The Bear Brook Watershed in Maine (BBWM) is a whole paired watershed manipulation experiment established to study the effects of N and sulfur (S) deposition on ecosystem function. N was added bimonthly as (NH₄)₂SO₄ to one watershed from 1989 to 2016, and research at the site has studied the evolution of ecosystem response to the treatment through time. Here, we synthesize results from 27 years of research at the site and describe the temporal trend of N availability and N mineralization at BBWM in response to chronic N deposition. Our findings suggest that there was a delayed response in soil N dynamics, since labile soil N concentrations did not show increases in the treated watershed (West Bear, WB) compared to the reference watershed (East Bear, EB) until after the first 4 years of treatment. Labile N became increasingly available in WB through time, and after 25 years of manipulations, treated soils had 10× more extractable ammonium than EB soils. The WB soils had 200× more extractable nitrate than EB soils, driven by both, high nitrate concentrations in WB and low nitrate concentrations in EB. Nitrification rates increased in WB soils and accounted for ~?50% of net N mineralization, compared to ~?5% in EB soils. The study provides evidence of the decadal evolution in soil function at BBWM and illustrates the importance of long-term data to capture ecosystem response to chronic disturbance.     

Indoor exposure to respirable particulate matter and particulate-phase PAHs in rural homes in North India

In order to evaluate the exposure of the northern India rural population to polyaromatic hydrocarbon (PAH) inhalation, indoor pollution was assessed by collecting and analyzing the respirable particulate matter PM_2.5 and PM₁₀ in several homes of the village Bhithauli near Lucknow, UP. The home selection was determined by a survey. Given the nature of biomass used for cooking, homes were divided into two groups, one using all kinds of biomass and the second type using plant materials only. Indoor mean concentrations of PM_2.5 and associated PAHs during cooking ranged from 1.19 ± 0.29 to 2.38 ± 0.35 and 6.21 ± 1.54 to 12.43 ± 1.15 μg/m³, respectively. Similarly, PM₁₀ and total PAHs were in the range of 3.95 ± 1.21 to 8.81 ± 0.78 and 7.75 ± 1.42 to 15.77 ± 1.05 μg/m³, respectively. The pollutant levels during cooking were significantly higher compared to the noncooking period. The study confirmed that indoor pollution depends on the kind of biomass fuel used for cooking.     

A survey of lead pollution in Chhattisgarh State, central India

Lead (Pb) is of major environmental concern due to its toxicological importance. The anthropogenic emission of Pb is at least 100 times higher than natural emissions. Soil and dust are significant sources of Pb exposure. Lead is generally immobile in soil and accumulates in the upper layers. Lead particles may enter homes via shoes, clothes, pets, and windows. Central India is rich in deposits of natural resource materials such as coal, pyrite, dolomite, and alumina that contain Pb and other heavy metals at the trace levels, and the substantial exploitation of these materials has tended to increased contamination of water and geological formations. Here we present data on Pb concentrations in the water, soil and sediment samples (n=158) collected from 70 locations in Chhattisgarh state, Raipur region. Lead concentrations in the surface water (n=44), groundwater (n=44), soils (n=60) and sediments (n=10) ranged from 6 to 1410, 3 to 52, 12.8 to 545, and 31 to 423 μg g⁻¹, with mean values of 305, 16, 102 and 190 μg g⁻¹, respectively. Most of the Pb fractions of >80% can be leached out with the chemical extractants EDTA, acetic acid, and hydroxylamine hydrochloride. Lead has accumulated in the soil clay fraction due to its relatively large surface area and decreases with increasing depth in the soil profile.     

Impact of gold mining associated with mercury contamination in soil,biota sediments and tailings in Kenya

This work considered the environmental impact of artisanal mining gold activity in the Migori–Transmara area (Kenya). From artisanal gold mining, mercury is released to the environment, thus contributing to degradation of soil and water bodies. High mercury contents have been quantified in soil (140 μg kg^?1), sediment (430 μg kg^?1) and tailings (8,900 μg kg^?1), as expected. The results reveal that the mechanism for transporting mercury to the terrestrial ecosystem is associated with wet and dry depositions. Lichens and mosses, used as bioindicators of pollution, are related to the proximity to mining areas. The further the distance from mining areas, the lower the mercury levels. This study also provides risk maps to evaluate potential negative repercussions. We conclude that the Migori–Transmara region can be considered a strongly polluted area with high mercury contents. The technology used to extract gold throughout amalgamation processes causes a high degree of mercury pollution around this gold mining area. Thus, alternative gold extraction methods should be considered to reduce mercury levels that can be released to the environment.     

Decentralised composting of urban waste--an overview of community and private initiatives in Indian cities

The national waste legislation, introduced in India in 2000, endorses the principle of "Recycle Before Disposal" and clearly stipulates composting as an option for organic waste treatment. It also recommends waste separation as prerequisite for treatment. Although various composting schemes of different scale, type and organisational structure currently exist in the country, a general overview is lacking and very little independent site-specific information is available. This paper presents the results of a study assessing 17 decentralised systems from the cities of Bangalore, Chennai, Pune, and Mumbai. The schemes were classified according to their organisational setup into: (1) citizens' and community initiatives; (2) business and institution initiatives operating on their premises; and (3) small and medium-size private sector initiatives. These categories also coincide with different operational scales. Community initiatives have developed from unreliable collection services, and composting emerged mainly as a spin-off activity from the collection system to reduce waste delivery to the communal containers emptied by the municipal services. The potential to launch and sustain decentralised composting schemes is dependent on the municipal provision of adequate space. This paper summarises further key issues pertaining to the assessed schemes and reveals overall deficiencies in the field of accounting and transparency, composting technique and marketing, as well as municipal authority involvement.     

Pet Waste Management by Chemical Recycling: A Review

The paper reviews the problem due to the use and disposal of synthetic polymers to the environment and its solutions; in particular poly (ethylene terphthalate). Wide spread application and non-biodegradability of the PET creates huge amounts of waste and disposal, tend to a serious problem. The most important cause for recycling and reprocessing the waste PET has arisen from the awareness and concern for environmental pollution. To manage this various methods of polymer recycling has been proposed. Among them chemical recycling, i.e. hydrolysis, methanolysis, glycolysis and aminolysis are reviewed in detail. Appropriate technology and waste disposal procedures based on the socio-economic aspect to solve this problem are suggested.     

Energy policies and collective self-reliance of the Third World

This paper reviews the broad pattern of energy use, output and consumption. The voracious consumption of non-renewable energy resources by the developed countries could exhaust this asset just when the accelerated development of the Third World would begin to gather momentum, thus denying them for their own use what is primarily their major resource. The paper underlines the critical importance of cooperative policies aimed at collective self-reliance of the Third World to ensure adequate availability of energy for its development.     

Degradations of endocrine-disrupting chemicals and pharmaceutical compounds in wastewater with carbon-based nanomaterials: a critical review

Environmental Science and Pollution Research - Although water occupies 75% of the earth’s surface, only 0.0067% of the total water is available for human activities. These statistics further...     

Effect of temperature and retention time on biomethanation of cheese whey-poultry waste-cattle dung

Various conditions, such as temperature, total solid content, cattle dung-poultry waste-cheese whey ratio, retention time and stirring, were optimized with an ultimate aim of improving anaerobic digestion. Maximum gas production (2.2 litres litre(-1) of digester day(-1)) with enriched methane content (62% CH(4)) was found with a retention time of 10 days, having a loading rate of 6.0 g total solid litre(-1) of digester day(-1) at 40 degrees C, and total solid of 6% (w/v) using a mixture of cattle dung, poultry waste and cheese whey in the ratio of 2:1:3 (w/w).