WATER

Worm Adverse Toxicity by Enviromental Routes (WATER) is a research project within SWIRL started in 2023 following reports by pharmaceutical companies such as AstraZeneca and Pzifer which highlighted the potential impact of pharmaceuticals in the enviornment (PiEs). 

The project is a collaborative project focusing on the pharmacological and ecological impact of human use of pharmaceuticals.

Below is an abstract of our findings to date. 

Introduction 

Cannabidiol (CBD) is a major non-psychoactive phytocannabinoid that has been detected in wastewater [1]. However, CBD's ecotoxicological effects remain unknown. We examine the in vivo effects of environmentally relevant concentrations of CBD [1] and its metabolite 7-hydroxycannabidiol (7-OH-CBD) [2] using the ecological indicator species, Lumbriculus variegatus. 

Methods 

CBD and 7-OH-CBD were dissolved in 100% DMSO or methanol, respectively, before dilution in artificial pond water [3] for a solvent concentration of 0.5% to give a final concentration of 0–5 μM. The ability of tactile stimulation to elicit stereotypical behaviours and the effect on unstimulated locomotor activity were conducted as previously described [3]. Oxygen consumption following exposure to 0–5 μM CBD or 7-OH-CBD was measured using Jenway 352012, and effects on blood vessel pulse rate was determined using the Nikon SMZ1270i. Energy reserves in L. variegatus homogenate was determined by the phenol-sulphuric acid method for carbohydrates, the vanillin-sulphuric acid assay for lipids and the Bradford assay for proteins. 

Results 

24-h exposure to CBD or 7-OH-CBD decreased tactile stimulation response to elicit stereotypical behaviours ≥2.5 μM or 5 μM, respectively. 5 μM CBD resulted in a significant decrease in locomotor activity (P = 0.002, n = 8), while no effect on locomotor activity was observed following 24-h exposure to 7-OH-CBD (P > 0.05, n = 8). 0–5 μM CBD had no effect on L. variegatus oxygen consumption (P > 0.05, n = 3), but ≥2.5 μM significantly reduced dorsal blood vessel pulsation rate (P < 0.05, n = 3). Conversely, L. variegatus oxygen consumption increased after 24-h exposure to 5 μM 7-OH-CBD (P = 0.034, n= 3) with no significant effect on pulse rate (P > 0.05, n = 3). Exposure to ≤2.5 μM 7-OH-CBD for 72 h did not affect energy reserves in L. variegatus homogenate, while 2.5 μM CBD resulted in a significant decrease in carbohydrates (P = 0.025, n = 6), increased lipids (P = 0.040, n = 6) and no effect on proteins (P >0 .05, n = 6). 

Conclusion 

We demonstrate that environmentally relevant concentrations of CBD can reduce L. variegatus behaviours, decrease pulsation rates and alter energy reserves in vivo. Therefore, these compounds, once released into the environment, merit further study to minimize ecological effects. 

References 

1. Mastroianni N, Postigo C, deAlda ML, Barcelo D. Illicit and abused drugs in sewage sludge: method optimization and occurrence. J Chromatogr A 2013;1322. https://doi.org/10.1016/j.chroma.2013.10.078. 

2. Zhang Q, Melchert PW, Markowitz JS. Pharmacokinetic variability of oral cannabidiol and its major metabolites after short-term high-dose exposure in healthy subjects. Med Cannabis Cannabioids 2024;7(1). doi: https://doi.org/10.1159/000535726. 

3. Seeley A, Bellamy C, Davies NA, Wallace MJ. Lumbriculus variegatus: a novel organism for in vivo pharmacology education. Pharmacol Res Perspect 2021;9:e00853. https://doi.org/10.1002/prp2.853.