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1.
Gowri VS Ramachandran S Ramesh R Pramiladevi IR Krishnaveni K 《Environmental monitoring and assessment》2008,138(1-3):41-49
Residential, industrial, commercial, institutional and recreational activities discharge degradable and non-degradable wastes
that reach the coastal water through rivers and cause coastal pollution. In the present study, mass transport of pollutants
by Adyar and Cooum Rivers to the coastal water as a result of land-based discharges was estimated during low tide. The lowest
and the highest flow recorded in Adyar varied from 514.59 to 2,585.08×106 litres/day. Similarly, the flow in Cooum River fluctuated between 266.45 and 709.34×106 litres/day. The present study revealed that the Adyar River transported 53.89–454.11 t/d of suspended solids, 0.06–19.64 t/d
of ammonia, 15.95–123.24 t/d of nitrate and 0.4–17.86 t/d of phosphate, 0.004–0.09 kg/d of cadmium, 0.15–1.29 kg/d of lead
and 3.03–17.58 kg/d of zinc to the coastal water owing to its high discharge. Similarly, the Cooum River transported 11.87–120.06 t/d
of suspended solids, 0.08–58.7 t/d of ammonia, 6.11–29.25 t/d of nitrate and 0.66–10.73 t/d of phosphate, 0.003–0.021 kg/d
of cadmium, 0.02–0.44 kg/d of lead and 1.36–3.87 kg/d of zinc. A higher concentration of suspended solids was noticed in post
monsoon and summer months. An increase in the mass transport of ammonia, nitrate, phosphate in summer months (April and May)
and an increase in the mass transport of cadmium, lead and zinc were observed in monsoon months (October–December) in both
the rivers. Thus mass transport of pollutants study reveal that Cooum and Adyar Rivers in Chennai contribute to coastal pollution
by transporting inorganic and trace metals significantly through land drainage. 相似文献
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A new Swiss TIMES (The Integrated MARKAL–EFOM System) electricity model with an hourly representation of inter-temporal detail and a century-long model horizon has been developed to explore the TIMES framework’s suitability as a long-term electricity dispatch model. To understand the incremental insights from this hourly model, it is compared to an aggregated model with only two diurnal timeslices like in most MARKAL/TIMES models. Two scenarios have been analysed with both models to answer the following questions: Are there differences in model solutions? What are the benefits of having a high number of timeslices? Are there any computational limitations? The primary objective of this paper is to understand the differences between the solutions of the two models, rather than Swiss policy implication or potential uncertainties in input parameters and assumptions. The analysis reveals that the hourly model offers powerful insights into the electricity generation schedule. Nevertheless, the TIMES framework cannot substitute for a dispatch model because some features cannot be represented; however, the long model time horizon and integrated system approaches of TIMES provide features not available in conventional dispatch models. The methodology of the model development and insights from the model comparison are described. 相似文献
4.
Radon (Rn(222)) levels in an indoor atmosphere of a multi-storey building at Mumbai have been measured for one year covering all the four seasons. Monitoring was carried out using the time-integrated passive detector technique, using Kodak-115 type Solid State Nuclear Track Detector (SSNTD) films of 2.5x2.5 cm size. Measured indoor radon levels showed a decreasing trend with height with concentration ranging from 41 Bq m(-3) at ground floor level to 15 Bq m(-3) at 19th floor level. Using the dose conversion factors, the inhalation dose due to breathing of radon gas is estimated to be 1.03 mSv y(-1) at the ground floor to 0.38 mSv y(-1) at the 19th floor level. Measured indoor radon concentrations on each floor were compared with the computed values using a mathematical model. The agreement between measured values and calculated values of indoor concentrations at different floors was very good within the limitations of various field parameter values. 相似文献
5.
Gurumurthy Ramachandran John L. Adgate Nicholas Hill Ken Sexton Gregory C. Pratt Donald Bock 《Journal of the Air & Waste Management Association (1995)》2013,63(7):1157-1166
ABSTRACT Measurements of 15-min average PM2.5 concentrations were made with a real-time light-scattering instrument at both outdoor (central monitoring sites in three communities) and indoor (residential) locations over two seasons in the Minneapolis-St. Paul metropolitan area. These data are used to examine within-day variability of PM2.5 concentrations indoors and outdoors, as well as matched indoor-to-outdoor (I/O) ratios. Concurrent gravimetric measurements of 24-hr average PM2.5 concentrations were also obtained as a way to compare real-time measures with this more traditional metric. Results indicate that (1) within-day variability for both indoor and outdoor 15-min average PM2.5 concentrations was substantial and comparable in magnitude to day-to-day variability for 24hr average concentrations; (2) some residences exhibited substantial variability in indoor aerosol characteristics from one day to the next; (3) peak values for indoor short-term (15-min) average PM2.5 concentrations routinely exceeded 24-hr average outdoor values by factors of 3-4; and (4) relatively strong correlations existed between indoor and outdoor PM2.5 concentrations for both 24-hr and 15-min averages. 相似文献
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Carbon Storage in Soil Size Fractions Under Two Cacao Agroforestry Systems in Bahia, Brazil 总被引:1,自引:0,他引:1
Emanuela F. Gama-Rodrigues P. K. Ramachandran Nair Vimala D. Nair Antonio C. Gama-Rodrigues Virupax C. Baligar Regina C. R. Machado 《Environmental management》2010,45(2):274-283
Shaded perennial agroforestry systems contain relatively high quantities of soil carbon (C) resulting from continuous deposition
of plant residues; however, the extent to which the C is sequestered in soil will depend on the extent of physical protection
of soil organic C (SOC). The main objective of this study was to characterize SOC storage in relation to soil fraction-size
classes in cacao (Theobroma cacao L.) agroforestry systems (AFSs). Two shaded cacao systems and an adjacent natural forest in reddish-yellow Oxisols in Bahia,
Brazil were selected. Soil samples were collected from four depth classes to 1 m depth and separated by wet-sieving into three
fraction-size classes (>250 μm, 250–53 μm, and <53 μm)—corresponding to macroaggregate, microaggregate, and silt-and-clay
size fractions—and analyzed for C content. The total SOC stock did not vary among systems (mean: 302 Mg/ha). On average, 72%
of SOC was in macroaggregate-size, 20% in microaggregate-size, and 8% in silt-and-clay size fractions in soil. Sonication
of aggregates showed that occlusion of C in soil aggregates could be a major mechanism of C protection in these soils. Considering
the low level of soil disturbances in cacao AFSs, the C contained in the macroaggregate fraction might become stabilized in
the soil. The study shows the role of cacao AFSs in mitigating greenhouse gas (GHG) emission through accumulation and retention
of high amounts of organic C in the soils and suggests the potential benefit of this environmental service to the nearly 6
million cacao farmers worldwide. 相似文献
8.
Asako Takimoto P. K. Ramachandran Nair Janaki R. R. Alavalapati 《Mitigation and Adaptation Strategies for Global Change》2008,13(7):745-761
The recognition of agroforestry as a greenhouse-gas mitigation strategy under the Kyoto Protocol to the United Nations Framework
Convention on Climate Change (UNFCCC) offers an opportunity to agroforestry practitioners to benefit from the global Carbon
(C) credit market. Our knowledge on this important topic from the semiarid regions such as the West African Sahel (WAS) is,
however, very limited. In order to fill this gap, this study was undertaken in the Ségou region of Mali (annual temperature,
29°C; annual rainfall, 300–700 mm in 60 to 90 days), focusing on two improved agroforestry systems (live fence and fodder
bank) along with traditional parkland agroforestry systems of the region. A cost–benefit analysis was conducted to assess
the economic profitability and risks associated with the systems considering them as 25-year projects and their potential
for participation in C credit market. The traditional systems had high C stock in their biomass and soil, but little potential
for sequestering additional C; on the other hand, the improved systems had low C stock, but high sequestration potential.
For the standard size live fence (291 m) and fodder bank (0.25 ha) projects, the estimated net present values (NPV) were $
96.0 and $158.8 without C credit sale, and $109.9 and $179.3 with C sale, respectively. From the C sale perspective, live
fence seemed less risky and more profitable than fodder bank. Carbon credit sale is likely to contribute to economic development
of the subsistence farmers in the WAS.
相似文献
Asako TakimotoEmail: |
9.
Reddy Yudhistir Ganguly Dipnarayan Singh Gurmeet Prasad Mamidala Harikrishna Arumughan Paneer Selvam Banerjee Kakolee Kathirvel Arumugam Ramachandran Purvaja Ramachandran Ramesh 《Environmental science and pollution research international》2021,28(31):42051-42069
Environmental Science and Pollution Research - Efficient nutrient cycling and adequate sediment bioavailable nutrient supply are considered to be the two most important factors regulating the high... 相似文献
10.
Forest Dynamics in the Eastern Ghats of Tamil Nadu,India 总被引:1,自引:0,他引:1
The primary deciduous forests in the Eastern Ghats (EG) of Tamil Nadu (TN) India have undergone many changes owing to various
need-based forest managements, such as timber extraction for industry, railway sleepers, charcoal, and forest clearance for
hydroelectric projects and agriculture, during preindependence and postindependence periods (i.e., from 1800 to 1980). The
enactment of a forest conservation act during the 1980s changed the perception of forest managers from utilization to conservation.
This study was taken up to assess the forests dynamics in the EG of TN spatially between 1990 and 2003 and nonspatially between
1900 and the 1980s. Landsat Thematic Mapper (TM) and Indian Remote Sensing satellite (IRS) 1D Linear Imaging and Self Scanning
(LISS III) data were used to assess forests during 1990 and 2003, respectively. Field floristic survey and secondary data
(such as published literature, floras, books, and forest working plans) were used to assess the forest dynamics in terms of
forest type and species composition among the preindependence period, the postindependence period, and the present (i.e.,
before and after 1980). The satellite data analysis revealed a considerable amount of changes in all forest types during the
13 years. The comparison of species composition and forest types between the past and present revealed that need-based forest
management along with anthropogenic activity have altered the primary deciduous forest in to secondary and postextraction
secondary forests such as southern thorn and southern thorn scrub forests in the middle [400–900 m above mean sea level (MSL)]
and lower slopes (<400 m MSL). However, the evergreen forests present at the upper slope (>900 m MSL) and plateau seemed not
to be much affected by the forest management. The changes estimated by the satellite data processing in the major forest types
such as evergreen, deciduous, southern thorn, and southern thorn scrub are really alarming because these changes have occurred
after the implementation of a forest conservation act. The dependence of local people on forests for various purposes in this
region is also considerably high, which might be a key factor for the changes in the forests. The results of this study not
only provide an outlook on the present status of the forests and the change trends but also provide the basis for further
studies on forests in the EG of TN. 相似文献