Pulp and paper mill effluents contain neuroactive substances that potentially disrupt neuroendocrine control of fish reproduction.
Here we show for the first time that components of pulp and paper mill effluents contain neuroactive substances that may impair fish reproduction. Grab samples of primary and secondary effluent were obtained from a representative pulp and paper mill in Eastern Canada. Effluents were fractionated using classic polarity and polyphenolic extraction methods into solvents of selected polarities (water, ethanol, ethyl acetate, and hexane). By means of in vitro, competitive assays on goldfish (Carassius auratus) brain tissues, the extracts were screened for their ability to interact with enzymes and receptors involved in gamma-aminobutyric acid (GABA), dopamine, glutamate, and acetylcholine-dependent neurotransmission. These neurotransmission pathways have essential regulatory roles in fish reproduction. Radioligand binding to the following neurotransmitter receptors were significantly impacted following in vitro incubations with extracts (percentage change from controls indicated in brackets): dopamine-2 (D2; 21-48% increase), GABA(A) receptor binding (65-67% decrease and 189% increase), N-methyl-o-aspartic acid (NMDA; 26-75% decrease), and muscarinic cholinergic (mACh; 42% increase). Activities of the following neurotransmitter-related enzymeswere significantly impacted: monoamine oxidase (MAO; 14-48% decrease), GABA-transaminase activity (33% decrease and 21-69% increase), and acetylcholinesterase (AChE; 21-50% decrease). No changes in glutamic acid decarboxylase (GAD) activity were detected. These findings provide a novel and plausible mechanism by which pulp and paper mills effluents impair fish reproduction by interacting with neurotransmitter systems. Furtherwork is required to identify the active compounds and explore whether these changes occur in vivo.
Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan 48109, USA.
Niladri
N
Basu
Chieu Anh
CA
Ta
Andrew
A
Waye
Jinqin
J
Mao
Mark
M
Hewitt
John T
JT
Arnason
Vance L
VL
Trudeau
D000818:Animals; D001921:Brain / Q000187:drug effects / Q000201:enzymology; D004784:Environmental Monitoring; D005419:Flavonoids; D006054:Goldfish / Q000502:physiology*; D007220:Industrial Waste; D008995:Monoamine Oxidase / Q000378:metabolism; D009490:Neurosecretory Systems / Q000187:drug effects*; D010209:Paper; D010636:Phenols; D059808:Polyphenols; D011954:Receptors, Dopamine / Q000378:metabolism; D012098:Reproduction / Q000187:drug effects*; D012997:Solvents; D013134:Spiperone / Q000633:toxicity; D014865:Waste Disposal, Fluid; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D005419:Flavonoids; D007220:Industrial Waste; D010636:Phenols; D059808:Polyphenols; D011954:Receptors, Dopamine; D012997:Solvents; D014874:Water Pollutants, Chemical; D013134:Spiperone; D008995:Monoamine Oxidase