Contamination levels assessment of potential toxic metals in road dust deposited in different types of urban environment

A total of 42 samples of road dust were collected along ring road, city centre, city side, and freeway in Urumqi, China. Total concentrations of Cd, Cr, Cu, Ni, Pb, Mn, Be, Co, Zn, and U were determined by using the inductively coupled plasma-mass spectrometry in order to assess and to compare road dust contamination levels of metals among the four roads. The results show that, among the four categories of roads, mean concentrations of Co and U vary little. City centre locations show strong enrichments of Cd, Cu, Pb, and Be. Along the ring road, the highest mean concentrations were found for Cr, Ni, Mn, and Co. However, the highest concentrations of Zn and U were found along the freeway. The cluster analysis shows that three main groups can be distinguished. Every group may be associated with different main sources and concentrations of the metals. The results of contamination assessment reveal that, among all of the potential toxic metals, Cd, Cu, and Zn pollution were obviously heavier with moderate or high contamination indices for most road dust samples, while Cr, Ni, and Pb contamination were lower along the four categories of roads. Compared with the city side, Cd, Cu, Pb, Ni, and Zn contamination were heavier along the ring road, the city centre, and the freeway with high traffic density. Low Pb contamination or no contamination in all the road dust samples may be related to the increasing usage of lead-free petrol.     

Quantitative vulnerability estimation for scenario-based landslide hazards

Within the engineering profession and natural sciences, vulnerability is widely accepted to be defined as the degree of loss (or damage) to a given element or set of elements within the area affected by a threat. The value of vulnerability is expressed nondimensionally between 0 and 1. It is a fundamental component in the evaluation of landslide risk, and its accurate estimation is essential in making a reasonable prediction of the landslide consequences. Obviously, vulnerability to landslides depends not only on the characteristics of the element(s) at risk but also on the landslide intensity. This paper summarizes previous research on vulnerability to landslides and proposes a new quantitative model for vulnerability of structures and persons based on landslide intensity and resistance of exposed elements. In addition, an approximate function is suggested for estimating the vulnerability of persons in structures. Different methods for estimating the vulnerability of various elements to slow or rapid landslides are discussed. Finally, the application of the new model is illustrated through an example.     

Role of selected riparian herbs in reducing soil erosion and nutrient loss under simulated rainfall

The native riparian herbs such as Leonotis nepetaefolia (L.) R. Br., Cassia tora L., Ageratum conyzoides L., Parthenium hysterophorus L. and Sida acuta burm f., dominant on the bank of River Damodar in Eastern Jharia Area, Dhanbad (India), were selected to assess experimentally their quantitative role in conserving the soil and reducing water runoff and nutrient (N and P) losses. A total of 42.5 mm simulated rainfall were applied at 30 cm h⁻¹ rain intensity on both vegetated and bare plots. The collected runoff water and eroded soil from each plot were determined in terms of soil, water and nutrient conservation value (CV). Among the vegetated plots, soil CV ranged from 30 to 85% and water CV from 20 to 48%. Nutrient (N and P) CV varied from 22 to 65% for total-N, 48 to 80% for ammonia-N and 50 to 86% for nitrate-N. CV for total-P varied from 40 to 62%, inorganic-P from 42 to 60% and organic-P from 20 to 58%. In a stepwise multiple regression equation comprising four independent variables (canopy cover, litter mass, soil moisture and plant biomass), canopy cover explained 70–88% (P < 0.01) of variability in conserving soil, water and nutrient. The losses through runoff water and eroded soil from vegetated plots were found to be minimized to a great extent as compared to bare plots. The role of these species in maintaining the texture and fertility status of riparian soil is discussed.     

Identification of temporal and spatial variations of water quality in Sanya Bay,China by three-way principal component analysis

A large data set obtained by a 1-year monthly determination of water quality from Sanya Bay, South China Sea, was treated by three-way principal component analysis aimed at exploring the spatial and temporal patterns of water quality in Sanya Bay. Tucker3 model of optimum complexity (2, 2, 1) explaining 33.18% of the data variance, allowed interpretation of the data information in three modes. The model explained spatial and temporal variation trends in terms of water quality variables during the study period. Water quality in sampling station (S2) Sanya River was mainly influenced by Sanya River, and water quality in other stations (S1, S3–S10) were mainly influenced by the waters in South China Sea. The results delineated the mouth of Sanya River as critical from pollution point of view. The dry season from October to the next April and rainy season from May to September have different influences on water quality in Sanya Bay. The information extracted by the three-way models would be very useful to regional agencies in developing a strategy to carry out scientific plans for resource use based on marine system functions.     

Application of Rock Mass Characterization for Determining the Mechanical Properties of Rock Mass: a Comparative Study

The results of geotechnical explorations, engineering geological investigation (including laboratory and in situ tests) and field observations have been used, along with borehole logging charts, to obtain the rock mass geotechnical data. Based on the data, the rock mass along the Sabzkuh water conveyance tunnel route was classified by rock mass rating (RMR), Q-system (Q), rock mass index (RMi) and geological strength index (GSI) (3 methods). A new series of correlations were established between the systems based on the data collected from the study area. These relationships were then compared with those reported in the literature, and two new relations were recommended. The classifications were utilized to calculate mechanical properties (rock mass strength and deformation modulus) of the rock mass along the tunnel according to available empirical relations, and to distinguish the upper-bound and lower-bound relations.     

First report of some Recent benthic foraminifera from the east coast of India

Twelve Recent benthic foraminiferal species hitherto not reported from the east and west coasts of India are presented and illustrated. They are, namely- Bolivina semicostata, Elphidium subgranulosum, Hanzawaia nipponica, Planorbulina variabilis, Pseudononion japponicum, Reussella haizumensis, Rosalina bradyi, Adelosina sp., Lagina sp. A, Lagina sp. B, Uvigerina sp. A and Uvigerina sp. B.     

Medium- and Long-term Recovery of Estuarine and Coastal Ecosystems: Patterns,Rates and Restoration Effectiveness

Many estuarine and coastal marine ecosystems have increasingly experienced degradation caused by multiple stressors. Anthropogenic pressures alter natural ecosystems and the ecosystems are not considered to have recovered unless secondary succession has returned the ecosystem to the pre-existing condition or state. However, depending upon the scales of time, space and intensity of anthropogenic disturbance, return along the historic trajectory of the ecosystem may: (1) follow natural restoration though secondary succession; (2) be re-directed through ecological restoration, or (3) be unattainable. In order to address the gaps in knowledge about restoration and recovery of estuarine and coastal ecosystems, this special feature includes the present overview and other contributions to provide a synthesis of our knowledge about recovery patterns, rates and restoration effectiveness. From the 51 examples collated in this contribution, we refine the recovery from the list of stressors into six recovery mechanisms: (1) recovery from sediment modification, which includes all aspects of dredging and disposal; (2) recovery by complete removal of stressors limiting natural ecosystem processes, which includes tidal marsh and inundation restoration; (3) recovery by speed of organic degradation, which includes oil discharge, fish farm wastes, sewage disposal, and paper mill waste; (4) recovery from persistent pollutants, which includes chemical discharges, such as TBT; (5) recovery from excessive biological removal, related to fisheries and (6) recovery from hydrological and morphological modification. Drawing upon experience both from these many examples and from an example of one comprehensive study, we show that although in some cases recovery can take <5 years, especially for the short-lived and high-turnover biological components, full recovery of coastal marine and estuarine ecosystems from over a century of degradation can take a minimum of 15–25 years for attainment of the original biotic composition and diversity may lag far beyond that period.     

Scattered Data Approximation on the Bisphere and Application to Texture Analysis

The paper deals with the approximation and optimal interpolation of functions defined on the bisphere \mathbb S²×\mathbb S²\mathbb {S}^{2}\times \mathbb {S}^{2} from scattered data. We demonstrate how the least square approximation to the function can be computed in a stable and efficient manner. The analysis of this problem is based on Marcinkiewicz–Zygmund inequalities for scattered data which we present here for the bisphere. The complementary problem of optimal interpolation is also solved by using well-localized kernels for our setting. Finally, we discuss the application of the developed methods to problems of texture analysis in material science.     

Assessment of NO<Subscript>3</Subscript><Superscript>−</Superscript> contamination in a karstic aquifer,with the use of geochemical data and spatial analysis

Kopaida plain is a cultivated region of Eastern Greece, with specific characteristic related with the paleogeographic evolution and the changes in land use. The present article examines the contamination that derives from nitrates, in terms of contaminant levels, definition of sources and spatial distribution of contaminant plume. For this purpose, 50 water samples were collected from the karstic aquifer and analyzed for 15 parameters including major ions, trace elements, physicochemical parameters, and stable isotopes. The assessment of the above parameter values along with the notes derived by the statistical process revealed the existence of nitrate contamination which has been spatial defined with the aid of spatial interpolation techniques. The correlation of NO₃ ⁻ concentrations with the stable isotope values, defined the infiltration conditions and showed contaminant transport. Nitrate values revealed the potential environmental threat for local people, as 10% of the samples exceeded the parametric value of 50 ppm and 54% of them are above 25 ppm, indicating no optimal quality conditions. The origin of nitrate contamination seems to derive exclusively from the application of N-fertilizers, since the rest of potential sources were not verified by analytical data and field works.     

2D stabilised analytic signal method in DC pole-pole potential data interpretation

Using analytic signal method, interpretation of pole-pole secondary electric potentials due to 2D conductive/resistive prisms is presented. The estimated parameters are the location, lateral extent or width and depth to top surface of the prism. Forward modelling is attempted by 2D-Finite Difference method. The proposed stabilised analytic signal algorithm (RES2AS) uses Tikhonov’s regularization scheme and FFT routines. The algorithm is tested on three theoretical examples and field data from the campus of Roorkee University. The stability of RES2AS is also tested on synthetic error prone secondary pole-pole potential data.