Effects Of Zinc/Salinity Combinations on Zinc Regulation inGammarus Duebenifrom the Estuary and the Sewage Treatment Works at Looe, Cornwall

Abstract

At Looe, Cornwall (south-west England), engineering problems have resulted in the Sewage Treatment Works operating on saline rather than the typical freshwater sewage input. Saline water enters the system at all stages of the tide, except low water, mainly through the open-jointed sewers embedded in the mud of the Looe River Estuary, and causes a cyclical salinity regime within the works (Jones & Johnson, in press). A consequence of this seawater intrusion is the replacement of the freshwater macroinvertebrate community commonly associated with biological filters by two species of euryhaline amphipods. In particular, Gammarus duebeni Liljeborg is permanently established at various sites in the works including the percolating filters and humus tanks (Jones & Wigham, 1988). The ability of G. duebeni to colonise and establish a breeding population at the works is probably a reflection of its wide tolerance to several environmental factors. This species is extremely euryhaline (Forsman, 1951; Sutcliffe, 1967; Pinkster, 1970) and can withstand marked hypoxic exposure (Bulnheim, 1979; Ritz, 1980). However, in addition to fluctuations in salinity and oxygen saturation, treatment works amphipods are exposed to relatively high levels of heavy metals associated with domestic and industrial inputs (Jones & Johnson, in press). Within the humus (secondary settlement) tanks, zinc concentrations are particularly elevated compared with the adjacent estuary, although there are considerable fluctuations in zinc levels experienced by animals due to the tidally based dilution of the incoming sewage (Jones & Johnson, in press).

Accumulation, regulation and toxicity of copper, zinc, lead and mercury in Hyalella azteca

“…Both metals were regulated by the amphipod, Allorchestes compressa, but copper accumulation at all exposure concentrations, although constant, was higher than in the control (Ahsanullah & Williams, 1991). Gammarus duebeni regulated zinc up to external zinc concentrations of 200 pg 1-' (Johnson & Jones, 1989), but Gammaruspulex demonstrated no zinc regulatory ability (Bascombe et al, 1990). The apparent copper and zinc regulatory abilities of amphipods, therefore, appear to vary somewhat from one study to another.…”

Reproductive biology of Orchestia gammarellus (Crustacea: Amphipoda) living in a sewage treatment works

“…In addition, the typical macro-invertebrate grazers associated with freshwater filters (Curds & Hawkes, 1975) have been replaced by two species of amphipod crustaceans, Gammarus duebeni Liljeborg and Orchestia gammarellus (Pallas) (Codling, 1984;Jones & Wigham, 1988). Studies of G. duebeni from the works indicate that 'sewage amphipods' are smaller and are more tolerant of hypoxia and elevated concentrations of zinc compared with G. duebeni from the Looe River estuary (Agnew & Jones, 1986;Johnson & Jones, 1989, 1990Jones & Johnson, 1992). The present paper describes the occurrence of G. duebeni and O.gammarellus at various sites within the treatment works, and examines the reproductive biology of O. gammarellus living in the percolating filter.…”