ABSTRACT

A disturbance in the normal physiology of soil macroinvertebrates can cause toxic impacts and/or disruption in mechanisms and rates of respiration. In this work, respiration rates of earthworms exposed to phenanthrene and its nitrogen heterocyclic analogs was investigated over a 30 and 90-d soil-contact-time. The study involved measurement and calculation of CO₂ production by earthworms exposed to phenanthrene–N-PAHs amended soils. Data showed that N-PAH chemicals mostly affected the respiration rates of the earthworms compared to the homologous-PAH analog over time. The concentration–time plots showed greater respiration with increase in concentration over time. Calculated respiration inhibition-effect (%) revealed that phenanthrene had low degree of inhibition (27%) in the first 30-d at the highest concentration, while, NPAHs exhibited high degree of inhibitions (>45%) on respiration/physiological function of the exposed earthworms over the 90-d contact-time. Among the N-PAH chemicals, benzo[h]quinoline recorded >25% inhibition even at the lowest concentration (30-d). Statistical analysis of data revealed that N-PAHs maintained strong positive correlation on respiration response of the organisms with increased concentration and time (R² = 0.803–0.997, p < .05). This suggests that N-PAH chemicals may have caused severe metabolic and physiological stress/inhibitions to soil organisms. Furthermore, the use of earthworm’s respiration rate in polluted soils could likely reshape the understanding of environmental stressors and serve as an early warning indicator for potential ecosystem shifts.

摘要

土壤大型无脊椎动物正常生理机能的紊乱会导致毒性影响和/或呼吸机制和速率的破坏。在这项工作中，在 30 天和 90 天的土壤接触时间中，研究了暴露于菲及其氮杂环类似物的蚯蚓的呼吸速率。该研究涉及 CO _{2 的}测量和计算暴露于菲-N-PAHs 的蚯蚓生产改良土壤。数据显示，与同源多环芳烃类似物相比，随着时间的推移，N-多环芳烃化学物质主要影响蚯蚓的呼吸速率。浓度-时间图显示随着时间的推移浓度增加，呼吸作用更大。计算的呼吸抑制效应（%）显示，菲在最高浓度的前 30 天具有低抑制程度（27%），而 NPAHs 对呼吸/生理功能表现出高度抑制（>45%）在 90 天的接触时间内暴露的蚯蚓。在 N-PAH 化学品中，苯并 [h] 喹啉即使在最低浓度（30 天）下也记录了 >25% 的抑制作用。²  = 0.803–0.997，p < .05）。这表明 N-PAH 化学品可能对土壤生物造成严重的代谢和生理压力/抑制。此外，利用蚯蚓在受污染土壤中的呼吸率可能会重塑对环境压力源的理解，并作为潜在生态系统变化的早期预警指标。