The purpose of this study is to determine the occurrence, movement, and sources of perchlorate in groundwater using a comprehensive set of environmental tracers coupled with discrete borehole data. Potential sources of perchlorate to groundwater at the study site have been attributed to waste disposal and industrial activities as well as to past agricultural operations. Perchlorate concentrations in samples ranged from <1 to 40 μg/l, with a median of 6.1 μg/l. Concentrations were relativity consistent with depth except at one site where dilution may be occurring due to the infiltration of surface water from Pyrite Creek. Well-bore flow profiles indicated that perchlorate redistribution was occurring via intra-well bore flow at one site where up to 14,000 mg/year of perchlorate could be moving from the shallower to the deeper zones of the alluvial aquifer. Natural attenuation processes of perchlorate do not appear to be widespread in groundwater but do occur in portions of the aquifer adjacent to the Santa Ana River, likely limiting the mobility of perchlorate from the southernmost extent of the mapped plume to areas farther down-gradient. Age dating tracers indicate that the advective transport of perchlorate originating from the waste disposal ponds has largely moved through the zones of the aquifer sampled. Age distributions, noble gas temperature, delta neon values and stable isotopes of water indicate that a substantial fraction of perchlorate in groundwater may have been mobilized from the unsaturated zone and/or is from the infiltration of storm water runoff originating from Pyrite Canyon.

这项研究的目的是使用一套综合的环境示踪剂和离散的井眼数据来确定地下水中高氯酸盐的发生，移动和来源。研究地点的地下水中高氯酸盐的潜在来源归因于废物处理和工业活动以及过去的农业活动。样品中的高氯酸盐浓度范围为<1至40μg/ l，中位数为6.1μg/ l。浓度是相对的，与深度一致，除了在一处可能会由于黄铁矿溪的地表水渗透而导致稀释的位置。井筒流动剖面表明，高氯酸盐的重新分配是通过一处井筒内的井筒流动发生的，最高可达14，000 mg /年的高氯酸盐可能从冲积含水层的较浅区域移至较深区域。高氯酸盐的自然衰减过程似乎并不普遍存在于地下水中，但确实发生在与圣安娜河相邻的含水层部分，这可能限制了高氯酸盐从测绘羽流的最南端向梯度更深的地区的迁移。年龄追踪示踪剂表明，源自废物处置池的高氯酸盐的平流运输在很大程度上穿过了采样的含水层区域。年龄分布，稀有气体温度，