Potential application of oxygen-18 and deuterium in mining effluent and acid rock drainage studies

 Oxygen-18 (¹⁸O) and deuterium (D, or ²H) are routinely used in hydrologic, climatologic and geothermal studies. In hydrology, stable isotopes provide information on the type and topology (altitude and latitude) of the recharge waters and the historical effects on water, related to such physical processes as evaporation (in ponds), melting (of snow or ice), condensation, evapotranspiration and mixing. In geothermal studies, stable isotopes provide key information related to recharge and the various temperature-dependent water/rock isotope exchange reactions. The latter is assessed through the oxygen shift in the ¹⁸O/D correlation. At acid rock drainage (ARD) sites, water/rock interactions are primarily controlled by pH and oxidation potential. Using the isotopic characteristics of the rocks and the recharge waters as a basis, the relative oxygen shift of the ARD effluent can provide information on: (1) the residence time, (2) the rate of water/rock reactions, and (3) the actual pH at the rock/water interface. This paper offers a methodology for conducting oxygen and hydrogen isotope studies related to ARD and other mineral effluent problems. The methodology is based on: (1) comprehensive sampling of regional waters, ARD effluent and major contributing minerals and rocks, (2) isotopic and elemental analysis, and (3) data interpretation on the basis of a zero-dimensional (mass balance), multi-component mixing model. Received: 15 January 1999 · Accepted: 3 May 1999     

Hydrochemical and stable isotope assessment of tailings pond leakage, Nickel Plate Mine, British Columbia

Received: 19 April 1999 · Accepted: 19 July 1999     

Operational Cost Comparison of Several Pre‐Treatment Techniques for OMW Treatment

Olive mill wastewaters (OMWs), which are known to have deep impacts on the receiving water bodies due to their high‐strength contents of organic materials and color, must be treated before discharge. For this reason; a number of research studies have been available in current literature related to the treatment of OMWs. However, no widely accepted treatment alternatives have been proposed yet. The common results of these studies suggest that OMWs must be pretreated prior to final purification processes. This study focuses on the comparison of alternative pre‐treatment processes in the aspect of chemical oxygen demand (COD) removal and costs of operation. Centrifuging, lime precipitation, acid cracking, and electrocoagulation processes were performed to compare removal efficiencies and operational costs. The COD removal efficiencies for centrifuging, lime precipitation, acid cracking, and electrocoagulation processes were determined to be 30.1, 24.1, 20.0, 53.7%, respectively, with operational costs being $0.30, $0.37, $1.42, and $11.60 per cubic meter of wastewater treated, respectively. The centrifuging process was concluded to be the most appropriate one according to the COD removal efficiency and cost of operation.     

Reflectance spectral characterization and mineralogy of acid sulphate soil in subsurface using hypcrspectral data

Acid sulphate soil（ASS） is a kind of soil which is harmful to the environment.ASS is hard to efficiently assess efficiently in the subsurface,although it is detectable on the surface by remote sensing.This paper aims to explore a new way to rapidly assess ASS in the subsurface by introducing a proximal hyperspectral instrument,namely the HyloggerTM system which can rapidly scan soil cores and provide high resolution hyperspectral data.Some minerals in ASS,which usually act as indicators of the severity of ASS,such as iron oxides,hydroxides,and sulphates,as well as some clay minerals,such as kaolinite,have diagnostic spectral absorption features in the reflectance spectral range（400-2500 nm）.Soil cores were collected from a study area and hyperspectral data were acquired by HyloggerTM scanning.The main minerals related to ASS were characterized spectrally,and were subsequently identified and mapped in the soil cores based on their reflectance spectral characteristics.Traditional X-ray diffraction（XRD） and scanning electron microscope（SEM） were also applied to verify the results of the mineral identification.The main results of this study include the spectral characterisation of ASS and its main compositional minerals,as well as the distribution of these relevant minerals in different depth of cores.     

Blast furnace slag can effectively remediate coastal marine sediments affected by organic enrichment

There is an urgent need to control nutrient release fluxes from organically-enriched sediments into overlying waters to alleviate the effects of eutrophication. This study aims to characterize blast furnace slag (BFS) and evaluate its remediation performance on organically-enriched sediments in terms of suppressing nutrient fluxes and reducing acid volatile sulfide. BFS was mainly composed of inorganic substances such as CaO, SiO₂, Al₂O₃ and MgO in amorphous crystal phase. Container experiments showed that the phosphate concentration in the overlying water, its releasing flux from sediment and AVS of the sediment decreased by 17-23%, 39% and 16% compared to the control without BFS, respectively. The loss on ignition was significantly decreased by 3.6-11% compared to the control. Thus, the application of BFS to organically-enriched sediment has a suppressive role on organic matter, AVS concentration and phosphate releasing flux from sediments and therefore, is a good candidate as an effective environmental remediation agent.     

Germination and establishment of the invasive cordgrass Spartina densiflora in acidic and metal polluted sediments of the Tinto River

Heavy metal pollution is common in rivers in the vicinity of mining areas. In these polluted environments, the survival of alien species with a high tolerance to metals may be favored. The Tinto River (Southwest Iberian Peninsula) is an excellent natural laboratory for the study of plants’ responses to acidic and metal polluted sediments. This work analyzes the tolerance of the alien species Spartina densiflora to low pH and high metal loads in the Tinto River. The main aim of this study was to determine if this alien species can invade landward along the banks of the Tinto River. S. densiflora seeds were able to germinate in heavy metal polluted aerobic sediments even at pH 2. However, these conditions decreased S. densiflora final germination, altered germination dynamics, decreased aerial and subterranean growth rates, and prevented its establishment.     

Changes of the plankton community composition during chemical neutralisation of the Bockwitz pit lake

Lake Bockwitz, a pit lake in a former lignite open-cast mine south of Leipzig (Germany), was neutralised (from pH 2.65 to pH 7.1) by addition of soda ash (14,620 t) from 2004 to 2007. The additions had to be continued due to ongoing inflows of acid ground and surface water. This paper reports on the changes in the plankton community accompanying the neutralisation.At the beginning, the community composition and biomass was comparable to other acidic pit lakes, i.e. the pigmented flagellates Chlamydomonas and Ochromonas dominated the autotrophs, and ciliates and rotifers were the top predators. The biomass was small (maximum 2 mg fresh weight per litre) and decreased until the end of 2008. With increasing pH, the autotrophic community became more diverse, whereby diatoms, chrysophyceans and blue greens contributed significantly to biomass. Although neutral pH conditions were achieved in autumn 2007, picocyanobacteria were not present until the end of 2008. In addition, crustaceans were under-represented in terms of biomass and diversity. Daphnids were not found. We attributed this to short-term changes of the ionic composition of the water and to the limited time available for non-acido-tolerant organisms to colonise the system.     

Simultaneous Analysis of Natural Free Estrogens and Their Sulfate Conjugates in Wastewater

Natural estrogens from humans increasingly attract attention because of their strong endocrine disrupting potency. The discharge of sewage water is considered as the most important source of these endocrine disrupting chemicals (EDCs) in the environment. Therefore, a GC‐MS method was developed for the simultaneous analysis of six natural free estrogens and their sulfate conjugates in municipal wastewater, in which natural free estrogens and sulfate conjugates were successfully separated from an Oasis HLB solid phase extraction (SPE) cartridge with two different eluents, and the sulfate conjugates were then transformed to their corresponding free estrogens by acid solvolysis. Before the analysis with GC‐MS, samples were derivatized by N,O‐bis (trimethylsilyl) trifluoroacetamide (BSTFA) plus 1% trimethylchlorosilane (TMCS) at 80°C for 40 min. Satisfactory recoveries ranging from 64 to 112.3% were obtained by spiking ultra‐purified water, raw, and treated municipal wastewater with the six estrogens at 50, 100, and 50 ng/L, respectively. The method was successfully applied to wastewater samples from one WWTP, which suggested that E1 was the dominant natural estrogens in effluent and E3‐3S was one of the conjugates possibly occurring in the effluent.     

2009年隆冬辽宁雨转暴雪和大雪过程对比分析

针对辽宁2009年2月中旬旬初雨转暴雪过程和旬末大雪过程,利用常规观测资料和NCEP 10×10 逐6 h分析资料,从环流形势、影响系统、水汽和动力条件及热力结构等方面入手,对这两次过程进行对比分析。结果表明：这两次过程在许多方面显著不同。两次过程均发生在乌山阻高稳定的形势下,均受中纬度东移的中尺度低值系统影响,但雨转暴雪过程中高纬度为两脊一槽型,中纬度短槽与南支低槽结合携强冷空气东移,与低空急流在辽宁上空交汇。大雪过程为东低西高型,中纬度气旋性波动东移,切变线北抬过程中与西南暖湿气流作用影响辽宁。两次过程均发生在600 hPa以下相对湿度为80%以上的大气中,均具有低层辐合高层辐散的特征和深厚的上升运动,但雨转暴雪过程水汽含量更高,辐合层更深厚、强度更强,垂直速度较大雪过程大一个量级;两次过程都有明显的风垂直切变特征,但雨转暴雪过程发生在风垂直切变迅速增大的条件下,大雪过程风垂直切变相对稳定;雨转暴雪过程降水随湿位涡的发展而增强,两者有较好的对应关系,而大雪过程湿位涡表现微弱;雨转暴雪过程槽前0 ℃层达到850 hPa,槽后各层温度迅速下降至0 ℃以下,而大雪过程整层温度始终在0 ℃以下。