Migration and accumulation of heavy metals in disturbed landscapes in developing ore deposits, East Kazakhstan

This paper studied the contents of heavy metals and their accumulation in the disturbed landscapes in ore deposits of East Kazakhstan. A total of 14 sites were examined in Zyrynovsky and Tishinsk deposits and Ridder town, and 50 soil samples were taken. Results indicated that the contents of heavy metals in the soil reached the maximum permissible concentration. Emissions of the zinc plant negatively affected the soil of nearby territories. In the remediated areas, a high concentration of heavy metals was observed at a depth where the bulk soil borders the rock. Accumulation of heavy metals on the surface of the remediated areas occurred due to biological accumulation in the plant. Plants transmitted heavy elements through the root system to the upper vegetative organs, making them accumulate in the upper layers of the soil. The heavy metals migrated and accumulated from the lower layers to the surface layers of the soil. The absence of soil meso-fauna resulted in the contamination of soil by heavy metals. The analysis of water samples, taken from the waste storages and the waste waters with heavy metals in the Zyryanovsk deposit and Ridder town, revealed severe water contamination.

Impacts of land disturbance and restoration on runoff production and sediment yield in the Chinese Loess Plateau

Land disturbance and land restoration are important factors influencing runoff production and sediment yield in the semi-arid loess regions of China. This study compared the runoff production and sediment yield during the early stage after land disturbance（ESLD） with those during restoring stage after land disturbance（RSLD）. Grey relational analysis was used to analyse the importance of each one of the influencing factors（vegetation, rainfall, soil and topography） in affecting the runoff production and sediment yield. Our results showed that during ESLD, topography was the most critical factor controlling the runoff production, while soil was the most important factor controlling the sediment yield. During RSLD, vegetation was more important in affecting runoff production, while rainfall was more important in affecting sediment yield. In additional, this study demonstrated that both the runoff production and the sediment yield can be effectively reduced by restoring vegetation on severely-disturbed lands, thus providing an important theoretical basis for better implementations of the Grain for Green Program. Our results revealed that the vegetation types of Hippophae rhamnoides＋Pinus tabulaeformis and H. rhamnoides are better plant selections for land restoration in this area, especially for relatively gentle slopes（i.e., less than 20 degrees）.

ENVIRONMENTAL ISSUES RELATED TO ENHANCED PRODUCTION OF NATURAL GAS BY HYDRAULIC FRACTURING

INTRODUCTION Hydraulic fracturing occurs when high pressure fluids primarily consisting of water and sand are pumped at high pressure into subsurface formations,typically shale that contains natural gas and/or oil.The high pressure fluid causes the rock to fracture.The new fractures increase the surface area of the shale and better interconnect previously existing fractures,allowing more natural gas and/or oil to be pumped from the formation.Modern hydraulic fracturing,referred to as“fracking,”is an evolving technology that largely began after 2000 and has significantly increased natural gas production in the United States in the past five years with corresponding decreases in natural gas prices.