Decision-making processes in ecological risk assessment using copper pollution of Macquarie Harbour from Mt. Lyell, Tasmania, as a case study

Ecological risk assessment is increasingly being used to make decisions on the acceptability of industrial processes, as well as on the appropriate approach to take with remediation of contaminated sites. In this approach, the risks and costs must first be determined before decisions can be made. In principle, the procedure for undertaking an ecological risk assessment for a site with existing contamination is fairly straight forward. Probability distributions are obtained for the concentration of the contaminant of concern and for the biological and/or structural impacts likely to occur in the affected habitat. The degree of overlap between these distributions determines the risk from the contaminant to the habitat. With water-borne contamination, the level of assessment can vary from a simple comparison with water quality criteria, through site specific literature surveys, to laboratory and field studies depending on the importance of the environment, the concentration and perceived nature of the contaminant,the resources available, and the likely benefit from the process to be developed. However, a number of uncertainties make this process more difficult. These include the lack of a standard methodology, availability of appropriate data and agreed definitions of acceptable risk. Thus several arbitrary or considered decisions need to be made before and during such an assessment. This paper discusses the application of an ecological risk assessment of copper pollution in Macquarie Harbour, Tasmania, using data from long-term monitoring of waters and literature searches on lethal and sub-lethal effects of copper in marine and estuarine environments. This study is part of a much larger program established to determine best methods for the remediation of the Mt. Lyell copper mine site as well as the freshwater and marine habitats downstream. The results of the assessment indicated that there was at present a probability greater than0.9 of the occurrence of anodic stripping voltametry-labile copper water concentrations harmful to 5% of all species. For total dissolved copper the probability was higher than 0.98. The upper value of total dissolved copper in Macquarie Harbour that encompassed 90% of the probable concentrations would need to be reduced by a factor of approximately 30,without the inclusion of any additional application factors, to achieve (sub-lethal) protection for 95%of species. This revised version was published online in August 2006 with corrections to the Cover Date.     

新疆焉耆盆地辣椒地土壤重金属污染及生态风险预警

从新疆加工辣椒主产地(焉耆盆地)采集105个辣椒地典型土壤样品,测定其中As、Cd、Cr、Cu、Mn、Ni、Pb和Zn等8种重金属元素的含量。采用污染负荷指数(Pollution load index,PLI)、潜在生态风险指数(Potential ecological risk index,RI)和生态风险预警指数(Ecological risk warning index,I_(ER))对辣椒地土壤重金属污染及生态风险进行评价。结果表明:(1)焉耆盆地辣椒地土壤Cd、Cr、Ni、Pb和Zn含量的平均值分别超出新疆灌耕土背景值的1.65、1.40、1.32、3.21、6.42倍。辣椒地土壤Pb和Zn呈现重度污染,Cd、Cr和Ni轻度污染,As、Mn和Cu无污染。(2)土壤PLI平均值为1.40,呈现轻度污染。各重金属元素单项生态风险指数从大到小依次为:Cd、Ni、As、Cu、Pb、Cr、Zn。土壤RI平均值为18.40,属于轻微生态风险态势,IER平均值为-4.78,属于无警态势;博湖县辣椒地污染水平、潜在生态风险程度与生态风险预警等级最高,焉耆县污染水平、潜在生态风险程度与生态风险预警等级最低。(3)辣椒地土壤As、Cd、Pb与Zn主要受到人类活动的影响,Cr、Cu、Mn和Ni主要受到土壤地球化学作用的控制。Cd是焉耆盆地辣椒地生态风险等级最高的重金属元素,研究区农业生产过程中要防范Cd的污染风险。     

Assessing the ecological health risk in a conserved mangrove ecosystem due to heavy metal pollution: A case study from Sundarbans Biosphere Reserve,India

Sundarbans Biosphere Reserve (SBR) is the world's largest contiguous conserved mangrove forest with unique flora and fauna, but it still has to bear the brunt of anthropogenic disturbances due to huge population pressure. This study aimed to identify the sources, extent of metal pollution (Cd, Cr, Mn, Ni, Pb, and Zn), and their potential ecological risk in this fragile ecosystem. Sediments were collected from 10 locations with varied levels of anthropogenic pressure from the fringe of the reserve forest. Cluster analysis (CA) and factor analysis (FA) identified Ni, Cd, and Pb as the major anthropogenic pollutants in this area. Concentrations of Pb (27.79–47.07 mg/kg) and Cd (0.8–3.3 mg/kg) were found to be higher in areas reliant on fossil fuel-operated motorboats for transport and dependent on rechargeable batteries to cope with the shortage of electricity. The contamination factor (C_f), geoaccumulation index (I_geo), and ecological risk index (ERI) highlight that populated areas are mostly exposed to Cd, Pb, and Cr contamination. Interpolation maps identified that the central part of the area is acutely affected by Cd pollution, whereas the main ecotourism routes within the reserve forest have high Pb concentrations. This study concludes that conservation-friendly ecotourism and improper disposal of batteries can also pose a threat to this ecosystem and these possibilities could be considered during formulation of conservation plans.     

Health risk assessment of heavy metals in groundwater of coal mining area: A case study in Dingji coal mine,Huainan coalfield,China

Heavy metals enrichment in groundwater poses great ecological risks to human beings. In the present research work, a total of 59 groundwater samples from 12 sampling points in Dingji coal mine, Huainan coalfield, were collected and measured for Cu, Pb, Zn, Cd, Ni, Mn, Cr, and Fe by inductively coupled plasma mass spectrometry (ICP-MS). The human health risk caused by heavy metals through the pathway of drinking water was evaluated and analyzed using the US Environment Protection Agency (USEPA) evaluation model. It has been found that the carcinogenic risk values were between 1.05 × 10^?5 and 3.5 × 10^?4, all exceeding the maximum acceptable level recommended by the USEPA, and the carcinogenic risk of Cr accounted for 99.67% of the total carcinogenic risk. The non-carcinogenic health risk values were all lower than the negligible level given by the USEPA, and the contribution of non-carcinogenic health risk was in the order of Cr > Zn > Cu / Pb >Mn > Fe > Cd > Ni. Among them, Cr had the largest contribution, accounting for 36% of the total non-carcinogenic risk value. In this study, the carcinogenic risk constituted 99.99% of the total health risk, indicating that the total health risk essentially consisted of carcinogenic risk. The research results suggest that much more attention should be paid to the health risk caused by Cr in the groundwater.     

Risk assessment of heavy metal and metalloid toxicity through a contaminated vegetable (Cucurbita maxima) from wastewater irrigated area: A case study for a site-specific risk assessment in Jhang,Pakistan

The present research was conducted in district Jhang, Pakistan, to evaluate the concentration of metals/metalloids in soil and pumpkin (Cucurbita maxima) irrigated with domestic wastewater. Data revealed that the levels of metals and metalloids in soil samples from two different sites were below the safe limits except Cd, whereas, in the vegetable, the concentrations of As, Se, Ni, Mo, Pb, Mn, and Cu were above the safe limits. The levels of 12 metals and metalloids in the soil were ranged between 0.14 to 22.76 mg/kg at site-I and 0.16 to 22.13 mg/kg at site-II. The levels of these metals in the vegetable were found 0.35 to 61.13 mg/kg at site-I and 0.31 to 53.63 mg/kg at site-II. The transfer factor at both sites was highest for As and Co. The pollution load index recorded for Se, Cu, Cd, Mo, Pb, and Co was greater than 1. The daily intake of As, Mn, and Mo was above the oral reference dose, which reflects that the intake of pumpkin is not safe for the inhabitants of the selected sites. The control measures should be taken to phytoextract heavy metals and metalloids from polluted sites so as to reduce the health risks.