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Effects of organic matter, alkalinity and p H on acute copper toxicity to mosquitofish, Gambusia holbrooki : Implications for a multipurpose management of irrigation ponds
Author(s) -
Sáez María I.,
Casas J. Jesús,
GuilGerrero José L.,
Gil María D.,
Cañero Rafael,
Suárez María D.
Publication year - 2013
Publication title -
international review of hydrobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.524
H-Index - 52
eISSN - 1522-2632
pISSN - 1434-2944
DOI - 10.1002/iroh.201301478
Subject(s) - gambusia , mosquitofish , alkalinity , organic matter , environmental chemistry , chemistry , population , water quality , ecology , zoology , biology , fishery , fish <actinopterygii> , demography , organic chemistry , sociology
This study evaluates the effects of water quality, i.e. organic matter content, alkalinity, and pH, on acute copper toxicity to mosquitofish ( Gambusia holbrooki Girard, 1859), an invasive species widespread in natural and artificial wetlands. The aim of this study was to improve our understanding of the consequences of CuSO 4 treatments on biodiversity conservation in irrigation ponds. Tests were carried out using three water types: irrigation‐pond water (IPW) of relatively high organic matter levels and slightly alkaline pH; IPW treated with sodium hypoclorite (IPW + SH) to remove organic matter and raise pH; dechlorinated tap water (DTW) with a relatively low alkalinity and organic matter, and a circumneutral pH. Fish were exposed for 96‐h under static conditions to 0.25, 0.75, 1.5, and 4 mgCu/L. Mortality was monitored every 24 h and LC 50 values were determined. After the 96 h period, the Cu concentration in gills was also determined. The LC 50 ‐96 h values were 1.90 (IPW), 1.51 (IPW + SH), and 0.78 (DTW) mg Cu/L, which can be considered relatively high. The concentration of copper in gills increased with the nominal Cu concentration in the three water treatments, and was significantly higher in DTW compared with IPW and IPW + SH. These results indicate that the relatively high alkalinity and, particularly, organic matter levels in pond water substantially buffer copper bioavailability to mosquitofish. However, chronic exposure to continuous Cu treatments and its accumulation in pond sediments are likely to produce stress symptoms at the individual and population levels of vertebrate and invertebrate species, which, besides agronomical and human health reasons, advise against using CuSO 4 as a management tool for irrigation ponds.