The aim of this study was to assess heavy metals mobility and toxicity in sediments collected from a dam reservoir in the conditions of intensive human impact by using chemical fractionation and a battery of bioassays. In the studies, the test organisms were exposed to substances dissolved in water (Microtox, Phytotestkit) as well to substances absorbed on the surface of solid particles (Phytotoxkit, Ostracodtoxkit F). The studies showed that sediments from the Rybnik reservoir are toxic, but the tested organisms showed different sensitivity to heavy metals occurring in the bottom sediments. The sediment samples were classified as toxic and very toxic. Moreover, the studies showed a higher toxicity in solid phases and whole sediment than in pore water. The lowest sensitivity was observed in H. incongruens (solid phases) and V. fischeri (pore water, whole sediment). The studies revealed that the toxicity of the sediments is caused mainly by heavy metal forms associated with the solid phase of the sediments. The studies did not confirm the metals occurring in fraction I (exchangeable) to be bioavailable and toxic to living organisms because most correlations between the metal concentration in fraction I and the response of the organisms were negative. The highest mobility from the bottom sediments was found in zinc, average mobility—in copper, cadmium and nickel, and low mobility—in chromium and lead. Organic matter is likely to be the most important factor controlling metal distribution and mobility in the studied sediments.

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Assessment of heavy metals mobility and toxicity in contaminated sediments by sequential extraction and a battery of bioassays

Fourteen water and sediment samples were collected from the Nakdong River Basin in Korea to evaluate the physico-chemical parameters (pH, dissolved oxygen, chemical oxygen demand, biological oxygen demand, total organic carbon) in water and total heavy metals (Cu, Zn, Pb, Cd, As) in surface sediments. The assessment of physico-chemical parameters indicates that river water and sediments in the study area were strongly impacted by industrial wastewater, irrigational effluents and domestic sewage. The overall average concentrations of metals in sediments were Cu (6.41 mg/kg), Cd (0.11 mg/kg), Pb (4.72 mg/kg), Zn (16.8 mg/kg), As (0.19 mg/kg), and the order of the concentrations was Zn > Cu > Pb > As > Cd. Geo-accumulation index (I
 geo) indicates that most of samples fall at unpolluted to medium category, while contamination factor values fall at the medium to very high pollution zone. Pollution load index also suggests that all samples fall at progressive pollution sector. Multivariate statistical analysis and pollution index methods were helpful for the classification on the basis of the contamination sources and origin of heavy metals. In conclusion, this study clearly infers the fact that the cause of metal pollution in this region is mainly due to the effluents discharged from factories, agricultural fields and sewers.

Evaluation of physico-chemical parameters in water and total heavy metals in sediments at Nakdong River Basin, Korea

Effect of flash flood on trace metal pollution in the groundwater - Wadi Baysh Basin, western Saudi Arabia

The present study is an attempt to assess the pollution intensity and corresponding ecological risk of heavy metals such as Cd, Ni, Pb, Cu, Zn and Cr using various indices like geo-accumulation index, concentration factor, pollution loading and ecological risk index. In all 21 surface sediments samples were collected from the stream flowing around the solid waste disposal landfill of Qayen city in southeastern Iran. Although Igeo values for Cd varied greatly, sites 18–21 with class 5 show heavy loads of Cd (values between 4.13 and 4.45). PLI values (3.37–12.89) clearly suggest strong contamination with respect to the measured metals. This study clearly indicates that the contamination risk in the downstream reservoir is much higher than upstream sites due to transfer and accumulation of leached metals from upstream to downstream.

Sediment Toxicity and Ecological Risk of Trace Metals from Streams Surrounding a Municipal Solid Waste Landfill

Rapid socioeconomic development in the Linggi River Basin has contributed to the significant increase of pollution discharge into the Linggi River and its adjacent coastal areas. The toxic element contents and distributions in the sediment samples collected along the Linggi River were determined using neutron activation analysis (NAA) and inductively coupled plasma-mass spectrometry (ICP-MS) techniques. The measured mean concentration of As, Cd, Pb, Sb, U, Th and Zn is relatively higher compared to the continental crust value of the respective element. Most of the elements (As, Cr, Fe, Pb, Sb and Zn) exceeded the freshwater sediment quality guideline-threshold effect concentration (FSQG-TEC) value. Downstream stations of the Linggi River showed that As concentrations in sediment exceeded the freshwater sediment quality guideline-probable effect concentration (FSQG-PEC) value. This indicates that the concentration of As will give an adverse effect to the growth of sediment-dwelling organisms. Generally, the Linggi River sediment can be categorised as unpolluted to strongly polluted and unpolluted to strongly to extremely polluted. The correlation matrix of metal-metal relationship, principle component analysis (PCA) and cluster analysis (CA) indicates that the pollution sources of Cu, Ni, Zn, Cd and Pb in sediments of the Linggi River originated from the industry of electronics and electroplating. Elements of As, Cr, Sb and Fe mainly originated from motor-vehicle workshops and metal work, whilst U and Th originated from natural processes such as terrestrial runoff and land erosion.

Multivariate analysis for source identification of pollution in sediment of Linggi River, Malaysia.

In this study, soundscape was analyzed through physical measurement and social surveys. The results showed that, soundscape components were related to functional partitions and tourist activities, at the same time influenced by ambient noise. The sound pressure levels showed daily regular changes. Semantic differential analysis showed that the evaluation of the soundscape in urban park was rather complicated. It was still possible to identify major factors including relaxation, spatiality and environment. The results provided theoretical basis for improving urban park soundscape, and called attention to this problem.

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Semantic Differential Analysis of the Soundscape in Urban Park

The contingent valuation method (CVM) was used along with a questionnaire survey and field research methods to analyze the factors affecting willingness to pay (WTP) for urban parks in Tai’an. The results indicated that roughly 50% of the residents visited the urban parks weekly. Doing physical exercises and viewing topped the list of activities. Residents of different characteristics had different WTPs for the service functions of urban parks. From the two surveys, 60.1% and 61.4% of residents would be willing to pay. The average individual WTPs were 42.2 yuan·a -1 and 43.1 yuan·a -1 in the two surveys, and the medianin dividual WTP was 20.0 yuan·a -1 . WTP was mainly affected by satisfaction, and WTP value was mainly affected by education level and income. Other factors had some correlation, but none were significant. Finally, some useful suggestions and references were given to the government in order to enhance the urban park services proposal. Key words : Urban park, Willingness to pay (WTP), Contingent valuation method (CVM), Correlation analysis

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Xiu-Hua Song

Papers

Semantic Differential Analysis of the Soundscape in Urban Park

Influencing the Willingness to Pay for Urban Park Service Functions