Behavioral Variables to Assess the Toxicity of Unionized Ammonia in Aquatic Snails: Integrating Movement and Feeding Parameters

Abstract

Behavioral endpoints are important parameters to assess the effects of toxicants on aquatic animals. These endpoints are useful in ecotoxicology because several toxicants modify the animal behavior, which may cause adverse effects at higher levels of ecological organization. However, for the development of new bioassays and for including the behavior in ecotoxicological risk assessment, the comparison of sensitivity between different behavioral endpoints is necessary. Additionally, some toxicants remain in aquatic environments for a few hours or days, which may lead to animal recovery after toxicant exposure. Our study aimed to assess the effect of unionized ammonia on the movement and feeding behaviors of the aquatic gastropod Potamopyrgus antipodarum (Tateidae, Mollusca) and its recovery after exposure. Four treatments were used: a control and three nominal concentrations of unionized ammonia (0.25, 0.5 and 1 mg N-NH3/L). Each treatment was replicated eight times, with six animals in each replicate. Animals were exposed to unionized ammonia for 48 h (exposure period) and, subsequently, to control water for 144 h (post-exposure period). Two movement variables were monitored without food and five feeding behavioral variables were monitored in the presence of food. Some of the feeding behavioral variables showed higher sensitivity (LOEC = 0.25–0.5 mg N-NH3/L) than the movement behavior variables monitored without food (LOEC = 1 mg N-NH3/L). After exposure to unionized ammonia, animals showed a recovery of most behavioral endpoints. The inclusion of post-exposure period and feeding behaviors in bioassays may make studies more realistic, which is crucial for a proper ecotoxicological risk assessment.

An IoT Based Water Quality Classification Framework for Aqua-Ponds through Water and Environmental Variables using CGTFN Model

“…Hidden state (ℎ 𝑡 ) = (1 -𝑧 𝑡 ) * ℎ 𝑝𝑟𝑒𝑣 +𝑧 𝑡 * ℎ 𝑡𝑖𝑙𝑑𝑎 𝑡 (7) The equation (7) updates the current hidden state (ℎ 𝑡 ) in an GRU cell by combining the previous hidden state…”

“…To overcome the challenges in water quality classification, our research adopts an Internet of Things (IoT) approach for data collection [7]. Strategically placed sensors gather real-time data on various environmental variables such as temperature, dissolved oxygen, pH value, nutrient concentration, humidity levels, wind direction, speed, and rainfall.…”

Ammonium oxidizing bacterial populations in South African activated sludge wastewater treatment plants

“…Both unionized ammonia (NH 3 ) and ammonium ions (NH 4 + ) are present in wastewater, with the unionized form being particularly toxic to aquatic biota (Alonso et al, 2022; Lin et al, 2022). The proportion of NH 3 increases with temperature and/or pH (pKa = 9.25 at 25°C) (Alonso et al, 2022). At temperatures ranging from 0 to 30°C, and within pH values typical of domestic wastewater (7–8), the proportion of NH 3 is low, ranging from 0.082% to 7.46%.…”

“…At temperatures ranging from 0 to 30°C, and within pH values typical of domestic wastewater (7–8), the proportion of NH 3 is low, ranging from 0.082% to 7.46%. However, this increases markedly as the pH increases and NH 3 concentrations as low as 1 mg/L can have adverse effects on biotic species (Alonso et al, 2022; Lin et al, 2022). It is therefore desirable to reduce the amount of NH 3 /NH 4 + in wastewater before discharge (Wade et al, 2010).…”

“…For example, in monthly influent samples taken from 16 wastewater treatment plants (WWTPs) located in three cities in South Africa (SA), inter‐city averages of 58.7 ± 19.0 mg/L (range: 38.1–102.0 mg/L, n = 82), 37.5 ± 19.2 mg/L (range: 6.5–94.9 mg/L, n = 76), and 23.8 ± 18.8 mg/L (range: 0.7–82.8 mg/L, n = 48) were measured (Welz et al, 2022). Both unionized ammonia (NH 3 ) and ammonium ions (NH 4 + ) are present in wastewater, with the unionized form being particularly toxic to aquatic biota (Alonso et al, 2022; Lin et al, 2022). The proportion of NH 3 increases with temperature and/or pH (pKa = 9.25 at 25°C) (Alonso et al, 2022).…”