CSIRO Land and Water, Lucas Heights, NSW 2234, Australia.
CSIRO Land and Water, Lucas Heights, NSW 2234, Australia.
Sci Total Environ. 2022 Mar 1;810:151219. doi: 10.1016/j.scitotenv.2021.151219. Epub 2021 Nov 6.
The Ok Tedi mine discharges waste rock and tailings into the Ok Tedi River in Papua New Guinea. This has resulted in elevated copper concentrations throughout the Ok Tedi/Fly River system, which can potentially impact aquatic biota. Ten years of measured copper and toxicity monitoring data were used to assess the risk of chronic effects from the mine-derived copper. Cumulative probability plots of dissolved and labile copper were compared to a species sensitivity distribution (SSD) of published copper toxicity data for four regions of the river. The Cu-SSD was used to estimate the risk of chronic effects to aquatic organisms in the Ok Tedi/Fly River at a range of potential copper exposure scenarios. The risk to species at the median labile copper concentration for each region showed a gradient effect with distance downstream from the mine and only the most sensitive (0.2-11%) species were at risk. There were copper exceedances of the region-specific guideline values (GV) and default guideline value (DGV) 88% and 74% of the time, respectively, in the Ok Tedi region (closest to the mine) and this is considered a high risk of chronic effects. Measured copper concentrations in the middle Fly River, lower Fly River (farthest downstream of the mine) and the river at Kiunga (reference site) exceeded the region-specific GVs and DGVs less frequently to rarely and present a lower risk of chronic effects from copper. The risk was supported using toxicity tests with the local microalgal species Chlorella sp. Comparison of recent (2010-2020) and historical (1996-2004) copper monitoring data from the Ok Tedi/Fly River indicates a decrease in the labile copper concentrations (30-76%) at key sites from impacted regions and a subsequent decrease in risk. This coincides with improved mining practices aimed at reducing the copper load into the Ok Tedi/Fly River.
奥克泰迪矿山将废石和尾矿排放到巴布亚新几内亚的奥克泰迪河中。这导致奥克泰迪/弗莱河系统中的铜浓度升高，这可能会对水生生物区系产生影响。利用十年来对铜的测量和毒性监测数据，评估了矿山衍生铜产生慢性影响的风险。将溶解态和生物可利用态铜的累积概率图与河流四个区域公布的铜毒性数据的物种敏感性分布（SSD）进行了比较。Cu-SSD 用于估算奥克泰迪/弗莱河流域在一系列潜在铜暴露情景下对水生生物产生慢性影响的风险。对于每个区域的中位生物可利用态铜浓度，风险表现出一种随距离矿山下游的梯度效应，只有最敏感的（0.2-11%）物种有风险。在奥克泰迪地区（最接近矿山），区域特定指导值（GV）和默认指导值（DGV）分别有 88%和 74%的时间超过了铜的超标值，这被认为是慢性影响的高风险。在弗莱河中游、弗莱河下游（离矿山最远的下游）和 Kiunga 河（参考点）的测量铜浓度较不频繁地超过了区域特定 GV 和 DGV，很少发生，因此铜产生慢性影响的风险较低。使用当地微藻物种 Chlorella sp. 的毒性试验也支持了这一风险。对奥克泰迪/弗莱河近期（2010-2020 年）和历史（1996-2004 年）铜监测数据的比较表明，受影响地区关键地点的生物可利用态铜浓度（30-76%）下降，风险随之降低。这与旨在减少奥克泰迪/弗莱河铜负荷的改进采矿做法相一致。
