Ecotoxicology & Risk Assessment Laboratory, Southeast Environmental Research Center, Department of Earth and Environment, Florida International University, 3000 NE 151st Street, North Miami, FL 33181, USA.
Ecotoxicol Environ Saf. 2011 May;74(4):1011-20. doi: 10.1016/j.ecoenv.2011.01.015. Epub 2011 Feb 22.
This study characterizes the effects of copper (Cu) on Florida apple snails (Pomacea paludosa) and mosquito fish (Gambusia affinis) using a replicated outdoor microcosm design. Soils used in this study were collected from two Cu-enriched citrus agricultural sites in South Florida (Agler property (AGLR) in St. Lucie County and Sunrise Boys property (SRB) in Palm Beach County) and a reference site (Equus property) in St. Lucie County. The study included a 5-week aging phase, an 11 month exposure phase, and a 3 month post-treatment (exposure) phase. The aging phase was initiated by flooding agricultural soils with rainwater in 4 m(3) fiberglass microcosm tanks. Introducing juvenile apple snails (≤7 d old) and mosquito fish (2-3 cm) into the microcosm tanks initiated the exposure phase. Survival, growth, and reproduction of apple snails and fish, and Cu uptake in apple snails, fish, and periphyton were determined in this study. Water chemistry (e.g., dissolved Cu concentration, dissolved organic carbon and dissolved oxygen concentrations, pH, hardness, alkalinity, etc.) was measured daily or weekly during the study. Initial soil Cu concentrations in Equus, SRB, and AGLR microcosms were 7, 55, and 99 mg/kg dw, respectively. Dissolved Cu concentrations in Equus, SRB and AGLR microcosms at the beginning of the study were 3, 82, and 43 μg/L, respectively and decreased to low saturation levels of about ≤9 μg/L Cu after the first 3 months of the study. The decrease of dissolved Cu concentrations was likely due to the dilution of rainwater. Snail and fish mortality appeared to be higher in SRB microcosms than in Equus and AGLR microcosms. There was no significant difference in growth of the snails between treatments. Snail growth data followed the von Bertalanffy Model. The maximum shell length, shell height, and shell width of the snails calculated by the von Bertalanffy Model (L(∞)) were 2.76, 2.05, and 2.18 cm, respectively. The maximum wet weight was 9.38 g. Growth rate (k) of the snails increased in order of shell height (0.459), shell length (0.550), and shell weight (0.598). There was no reproduction in the snails in any treatments including the reference during the exposure phase. However, Cu did not affect reproduction of fish during this period. Copper concentrations in periphyton from Equus, SRB, and AGLR microcosms ranged from 2 to 62, 31 to 371, and 13 to 478 mg/kg, respectively. Copper concentrations in fish at the beginning, days 30 and 150 of the study ranged from 3.19 to 7.53 mg/kg and were not significantly different from the different treatments. Average Cu concentrations in the soft tissue of dead snails from SRB and AGLR microcosms were 4602 mg/kg dw (ranged from 2913 to 8370 mg/kg dw) and 2824 mg/kg dw (ranged from 2118 to 3600 mg/kg dw), respectively. The Cu concentrations in the soft tissue of dead snails found in this study were higher than the tissue Cu concentrations in live aquatic organisms reported in the literature. These high Cu concentrations in edible apple snail soft tissue might pose a risk to Florida apple snail predators, including the snail kite. The post-exposure phase, with snails exposed to only water (i.e., no soils) showed depuration of copper from apple snails and reproduction in all treatments.
本研究采用复制室外微宇宙设计，研究了铜（Cu）对佛罗里达苹果蜗牛（Pomacea paludosa）和食蚊鱼（Gambusia affinis）的影响。本研究中使用的土壤取自南佛罗里达州两个富含铜的柑橘农业区（圣卢西亚县的 Agler 物业（AGLR）和棕榈滩县的 Sunrise Boys 物业（SRB））和圣卢西亚县的参考地点（Equus 物业）。该研究包括 5 周的老化阶段、11 个月的暴露阶段和 3 个月的暴露后（暴露）阶段。通过在 4 m³玻璃纤维微宇宙罐中用雨水淹没农业土壤开始老化阶段。将幼年苹果蜗牛（≤7 天大）和食蚊鱼（2-3 厘米）引入微宇宙罐中开始暴露阶段。本研究中确定了苹果蜗牛和鱼类的存活率、生长率和繁殖率，以及苹果蜗牛、鱼类和周丛生物体内的 Cu 吸收量。在研究过程中，每天或每周测量水化学性质（例如溶解 Cu 浓度、溶解有机碳和溶解氧浓度、pH 值、硬度、碱度等）。Equus、SRB 和 AGLR 微宇宙中的初始土壤 Cu 浓度分别为 7、55 和 99 mg/kg dw。研究开始时，Equus、SRB 和 AGLR 微宇宙中的溶解 Cu 浓度分别为 3、82 和 43μg/L，在研究的前 3 个月后降至约≤9μg/L Cu 的低饱和水平。溶解 Cu 浓度的降低可能是由于雨水的稀释。SRB 微宇宙中的蜗牛和鱼类死亡率似乎高于 Equus 和 AGLR 微宇宙。处理之间的蜗牛生长没有明显差异。蜗牛生长数据遵循 von Bertalanffy 模型。von Bertalanffy 模型（L（∞））计算的蜗牛最大壳长、壳高和壳宽分别为 2.76、2.05 和 2.18 cm，最大湿重为 9.38 g。蜗牛的生长率（k）按壳高（0.459）、壳长（0.550）和壳重（0.598）的顺序增加。在暴露阶段，包括参考组在内的所有处理中，蜗牛均未繁殖。然而，在此期间 Cu 并未影响鱼类的繁殖。Equus、SRB 和 AGLR 微宇宙中周丛生物的 Cu 浓度分别为 2-62、31-371 和 13-478 mg/kg。研究开始时、第 30 天和第 150 天鱼类体内的 Cu 浓度范围为 3.19-7.53 mg/kg，与不同处理之间无显著差异。SRB 和 AGLR 微宇宙中死亡蜗牛软组织中的平均 Cu 浓度分别为 4602 mg/kg dw（范围为 2913-8370 mg/kg dw）和 2824 mg/kg dw（范围为 2118-3600 mg/kg dw）。本研究中发现的死亡蜗牛软组织中的 Cu 浓度高于文献中报道的活体水生生物组织中的 Cu 浓度。食用苹果蜗牛软组织中如此高的 Cu 浓度可能对佛罗里达苹果蜗牛的捕食者（包括食蜗鸢）构成风险。暴露后阶段，蜗牛仅暴露于水中（即无土壤），结果表明苹果蜗牛体内的 Cu 被清除，所有处理均有繁殖。
