Assessment of the effects of non-aqueous phase liquid (NAPL) pollution on aquatic macroinvertebrates survivorship

Massive production, extensive use and poor disposal practices of organic chemicals from industries and fuel facilities have polluted soil and water resources. Non-aqueous phase liquids (NAPLs), including oils and fuel hydrocarbons are immiscible in water, moving as separate layers based on their density. Due to their high persistence, they are seldom flushed from the system, potentially making it unfit for use later. Along with resource consumption, pollution also poses a threat to dependent aquatic life. NAPLs have the potential to disturb the physiological, behavioral and breeding performance of aquatic organisms, by affecting their oxygen and nutrient uptake from the system. To analyze these effects, this study examined the response of two common European freshwater macroinvertebrates: Gammarus pulex (freshwater shrimp) and Baetis rhodani (mayfly larvae) to controlled exposure of mineral oil (a representative NAPL). The experiments were conducted in the laboratory for a 24-hour period to observe any changes in their locomotion and survivorship at different concentrations of mineral oil. Results indicate that mineral oil has a serious effect on the organism’s movement and survivorship. Gammarus pulex displayed a high tolerance compared to the mayfly (Baetis rhodani). Most mayfly larvae died due to NAPL exposure. The results indicate that both organisms respond rapidly to NAPL contamination, providing the potential for the development of bio-monitoring tools for water quality studies.

Keywords: Aquatic macroinvertebrates, NAPLs, pollution, response