A laboratory study on risk assessment of microcystin-RR in cropland

The persistence time and risk of microcystin-RR (MC-RR) in cropland via irrigation were investigated under laboratory conditions. In order to evaluate the efficiency of the potential adsorption and biodegradation of MC-RR in cropland and the persistence time of MC-RR for crop irrigation, high performance liquid chromatography (HPLC) was used to quantify the amount of MC-RR in solutions. Our study indicated that MC-RR could be adsorbed and biodegraded in cropland soils. MC-RR at 6.5 mg/L could be completely degraded within 6 days with a lag phase of 1 - 2 days. In the presence of humic acid, the same amount of MC-RR could be degraded within 4 days without a lag phase. Accordingly, the persistence time of MC-RR in cropland soils should be about 6 days. This result also suggested the beneficial effects of the organic fertilizer utilization for the biodegradation of MC-RR in cropland soils. Our studies also demonstrated that MC-RR at low concentration (< 10 mu g/L) could accelerate the growth of plants, while high concentration of MC-RR (> 100 mu g/L) significantly inhibited the growth of plants. High sensitivity of the sprouting stage plants to MC-RR treatments as well as the strong inhibitory effects resulting from prolonged irrigation further indicated that this MC-RR growth-inhibition may vary with the duration of irrigation and life stage of the plants. (c) 2007 Published by Elsevier Ltd.

Analysis of heavy metals of muscle and intestine tissue in fish - in Banan section of Chongqing from Three Gorges Reservoir, China

The present study was carried out to investigate contamination of heavy metals in 19 fish species from the Banan section of Chongqing in the Three Gorges, Yangtze River. The results showed that the mean concentrations of heavy metals were higher in intestine than muscle, except zinc in upper strata. In the fish inhabiting the upper strata, there were significant differences between mean concentrations of As, Cr, Cu and Hg in muscle and intestine (P <0.05). There were also significant differences between mean concentrations of Cr and Cu in muscle and intestine in the fish inhabiting middle strata. However, significant differences between mean concentrations of As, Cd, Hg, Pb and Zn were measured in fish inhabiting bottom strata in both intestine and muscle tissues (P <0.05). For the fish inhabiting different strata, the concentrations of As, Cd, Cr, Cu, Hg and Ph in muscle and intestine of the fish from bottom strata (BS) were higher than those in both upper strata (US) and middle strata (MS); whereas a higher concentration of Zn was measured in muscle and intestine from fish inhabiting upper strata. Mean metal concentrations were found to be higher in age 11 than those in age I in Coreius heterodon (2- and 1-year odl fish respectively). The overall results indicated that fish muscle in the Banan section were slightly contaminated by heavy metals, but did not exceed Chinese food standards.

A methodology of characterizing status and trend of land changes in oases: A case study of Sangong River watershed, Xinjiang, China

National Natural Science Foundation of China [40471134]; program of Lights of the West China by the Chinese Academy of Science

Spatial and temporal flows of China's forest resources: Development of a framework for evaluating resource efficiency

Science & Technology Basic Work Program of China: Scientific Survey of the Middle-lower Reaches of Lantsang River and the Great Shangri-La Region [2008FY110300]; National Basic Research Program of China (973 Program): Ecosystem Services and Ecological Safety of the Major Terrestrial Ecosystems of China [2009CB421106]; National Natural Science Foundation of China [30670374]; EU ; European Commission, DG Research [003874]

A nonlinear model for assessing multiple probabilistic risks: A case study in South five-island of Changdao National Nature Reserve in China

Several methods for estimating the potential impacts caused by multiple probabilistic risks have been suggested. These existing methods mostly rely on the weight sum algorithm to address the need for integrated risk assessment. This paper develops a nonlinear model to perform such an assessment. The joint probability algorithm has been applied to the model development. An application of the developed model in South five-island of Changdao National Nature Reserve, China, combining remote sensing data and a GIS technique, provides a reasonable risk assessment. Based on the case study, we discuss the feasibility of the model. We propose that the model has the potential for use in identifying the regional primary stressor, investigating the most vulnerable habitat, and assessing the integrated impact of multiple stressors. (C) 2006 Elsevier Ltd. All rights reserved.