Survival, reproduction, and arsenic body burdens in Chironomus riparius exposed to arsenate and phosphate

Abstract

Despite the increasing awareness of arsenic (As) contamination in surface waters worldwide, little is known about how As alone and in the presence of other chemicals affects aquatic insects. Larvae of Chironomus riparius were exposed in a laboratory investigation to factorial combinations of 0, 0.13, 2.0, 5.3, and 13μmolAsl−1 and 0, 0.15, and 15μmolPO4l−1 throughout development from first instar to pupal emergence. The time between male and female emergence increased from 1.8±0.17days to 2.9±0.34days with exposure at higher As levels. The highest As exposure also decreased the number of eggs per egg mass, which may affect population maintenance. For these parameters, there was no effect from PO4, and no interaction between As and PO4. Total As determination of larval and adult tissues was conducted using Hydride Generated Atomic Absorption Spectroscopy (HGAAS) and revealed concentrations ranging from 2.48±0.363 to 30.5±0.473μg/g and 1.03±0.286 to 8.97±0.662μg/g, respectively, indicating elimination of approximately 72% of total As body burdens between the fourth instar and adult stages. There was no effect of PO4, indicating PO4 does not alter uptake of As in C. riparius. The potential for movement of As to terrestrial systems exists, though trophic transfer may be more likely during the aquatic larval stage.