Effects of dechlorinated seawater on fish behavior

Behavioral responses to chemically dechlorinated seawater were studied using two species of marine fish associated with power plant discharge areas off Southern California. Opaleye (Girella nigricans) neither avoided nor were attracted to chlorinated seawater containing 0·1 mg/liter total residual oxidants (TRO) which had been dechlorinated using equimolar or excess sodium thiosulfate. Blue-banded goby (Lythrypnus dalli) did not avoid dechlorinated seawater initially containing 0·1 or 0·9–1·0 mg/liter TRO. Previously it has been shown that opaleye avoided chlorinated seawater with oxidant concentrations of 0·1 mg/liter and blue-banded gobies avoided 0·9–1·0 mg/liter TRO. Elimination of chlorine-produced oxidants by thiosulphate dechlorination resulted in 100% survival in both species. The toxicological implications of exposure to dechlorinated seawater are discussed.     

Physiological responses of a marine fish exposed to chlorinated seawater at concentrations near its avoidance threshold

To determine if avoidance of chlorinated seawater by fish resulted in physiological protection from toxicity, studies were carried out which assessed (a) changes in the routine oxygen consumption rate and (b) the ability of treated fish to successfully compete with untreated conspecifics for a limited food resource.Temperate marine damselfish, Chromis punctipinnis, were exposed to stepwise increasing levels of chlorinated seawater in a behaviour chamber and avoided total residual oxidant (TRO) levels greater than 0·15-0·16 mg/litre. Cumulative exposures ranged from the equivalent of 0·38-5·23 in at 1·0/litre TRO. One day after exposure, routine oxygen consumption rates were decreased by 25 to 45% from pre-exposure rates and were correlated with the cumulative oxidant exposure. One month post exposure, respiration rates returned to pre-treatment levels. This transient depression of the respiratory rate did not affect survival or growth of chlorine-treated fish which were forced to compete with untreated conspecifics for a restricted food supply.     

Sea urchin sperm bioassay for sewage and chlorinated seawater and its relation to fish bioassays

Bioassays were conducted with sea urchin and sand dollar sperm to determine the toxicity of chlorinated and unchlorinated sewage effluent and chlorinated and brominated seawater. The sperm cells were exposed to seawater dilutions of each toxicant for 5–15 min. The fertilisation of eggs served as the indicators of sperm viability. The effective concentrations which reduced fertilisation success by 50% (EC50) averaged 2·2 and 4·8% chlorinated and unchlorinated sewage in seawater, respectively. The sperm cells were extremely sensitive to chlorinated seawater at concentrations from 0·002 to 0·020 mg/litre total residual oxidant (TRO). Brominated seawater proved toxic to sperm in one test at 0·015 mg/litre TRO. Results of the sperm bioassays are compared with previous acute and chronic bioassays with fish.     

Cadmium toxicity to three species of estuarine invertebrates

Three species of estuarine invertebrates, Palaemonetes pugio (grass shrimp), Pagurus longicarpus (hermit crab) and Argopecten irradians (bay scallop), were exposed to Cd in flowing seawater at concentrations of 0·06, 0·12, 0·25, 0·5 and 1·0 mg/litre. Incipient LC₅₀ values of 0·53 and 0·07 mg/litre were estimated for bay scallop and hermit crab, respectively. The toxicity curve for grass shrimp had not stabilised, but the incipient LC₅₀ value was estimated to fall within a range of 0·2 to 0·3 mg/litre. Short-term response, as measured by time to 50% mortality at the highest Cd concentration, was 10, 21 and 23 days for the bay scallop, hermit crab and grass shrimp, respectively. Scallop growth was inhibited at all exposure concentrations with a measured 42-day EC₅₀ value of 0·078 mg/litre Cd. Byssal thread detachment precedes death in bay scallops. An EC₅₀ value of 0·54 mg/litre Cd for byssal detachment was measured on day 8 of the bioassay before appreciable mortality. This compared favourably with the incipient LC₅₀ value of 0·53 mg/litre Cd. Cadmium accumulation occurred at all concentrations in bay scallop and grass shrimp.     

Disruption of magnesium regulation in the crab Cancer productus exposed to chlorinated seawater

Exposure of the crab Cancer productus to chlorinated seawater resulted in alterations in haemolymph sodium and magnesium concentrations. At the highest chlorination levels, which approached the 96-h LC₅₀, regulation of both ions was essentially abolished. Reciprocal changes in the sodium and magnesium levels suggested an effect on the activity of the bladder wall, which has been implicated in the regulation of haemolymph magnesium in crustaceans.Additionally, exposure to 1·19 μg/ml applied Cl (0·68 μg/ml TRO) for 96 h resulted in a fourfold increase in the ammonia excretion rate. Crabs also contributed considerable chlorine demand to the exposure seawater. Measurements of TRO in the inhalant seawater and water exiting the crabs' branchial chambers indicated a reduction in TRO equivalent to 57% of that initially present in the inhalant water (0·51 μg/ml TRO).Measurements of ammonia concentrations in the exposure water indicated that ammonia in seawater was consumed in reactions with oxidants. This was especially evident at higher levels of chlorination. At 0·58 μg/ml applied Cl and above, chlorination resulted in near disappearance of ammonia from the water.     

A comparison of ozone and chlorine toxicity to three life stages of the American oyster Crassostrea virginica

The effects of ozone-produced oxidants (OPO) on three developmental stages of the American oyster, Crassostrea virginica, were evaluated. Both straight-hinge (48-h post fertilisation) and setting pediveliger larvae were exposed to a series of OPO concentrations ranging from 0·05 to 0·30 mg/litre OPO (as total residual chlorine) at 25°C for 96 h. Mortality was used as the response parameter and results were quantitatively compared with the effects of chlorine-produced oxidants (CPO) obtained from the literature on these same developmental stages. Adult oysters (2- to 4-year class) were exposed to OPO concentrations ranging from 0·01 to 0·50 mg/litre at 15°C for 5 days and to the same concentration range at 25°C for two consecutive 6-day periods. Shell deposition and faecal matter accumulation were used as the response parameters for this stage.Straight-hinge larvae were significantly more sensitive to OPO than setting pediveliger larvae. Both larval stages were significantly more sensitive to CPO than to OPO. Shell deposition was significantly inhibited at all OPO concentrations for both 15°C and 25°C acclimated adult oysters. No significant differences were found between the shell deposition response of oysters at the two acclimation temperatures. Faecal matter accumulation was significantly reduced at OPO concentrations ≥ 0·05 mg/litre at both 15°C and 25°C. It was significantly (p < 0·05) greater for 25°C acclimated oysters than for 15°C acclimated oysters at OPO concentrations < 0·10 mg/litre but not at higher concentrations.     

Phenolics in aquatic ecosystems: A selected review of recent literature

This review surveys the pertinent literature on phenolics in the aquatic ecosystem. Approximately 2% of the total organics manufactured in the US were phenols. Of the total phenolics produced in the US, 96% were synthetic and 4% were naturally occurring. Synthetic phenols arise from coking of coal, gas works and oil refineries, chemical plants, pesticide plants, wood preserving plants and dye manufacturing plants. Natural phenolics occur from aquatic and terrestrial vegetation and much of this is released by the pulp and paper industry.Toxicity of phenolics has been studied on selected microbes (e.g. protozoa, yeast and bacteria), algae, duckweed, and numerous invertebrates and vertebrates. Depending on the organism tested, the acute toxicity of phenol varies from 6·5 to 1840 mg/litre phenol. For other phenolics toxicity ranges from 0·084 to 555 mg/litre. The toxicity of phenolics varies with the type, position and number of substitutions on the parent molecule. Environmental factors affect the toxicity of phenolics and these include photolytic action, microbial degradation, pH, water hardness and temperature. Based on limited data, toxicity of phenolics may be less in continuous flow tests than in their sensitivity to phenolics as does the presence of oxygen. A seasonal factor may also affect the sensitivity of various fish. Starvation and lack of suitable substrate for bottom fauna increases organism sensitivity to phenol. The source of test animals may affect their sensitivity to phenolics and this effect may be due to short-term physiological acclimation and genetic selection.Studies on the biological effects of phenolics are limited and varied. Fish development and embryo survival were not affected by phenol levels less than 25 mg/litre. Amphibian embryos were sensitive to 0·5 mg/litre phenol. Pentachlorophenols inhibited fish growth at levels down to 1·74, μg/litre.Exposure of fish to phenol in concentrations as low as 4 mg/litre caused haemorrhaging at the base of the fins. Two hour exposure to 6·5 mg/litre phenol caused disruption of blood vessel walls and gill epithelium. Oedema and blood infiltration was a common effect observed in most major tissues studied from fishes exposed to phenol. Phenol, at 12·5 mg/litre, reduces the levels of neurohormones in fish exposed for 10 days. The effects of pentachlorophenol on blood glucose and blood lactate levels, and in vivo and in vitro activity levels of seven liver enzymes of eels are discussed. Pentachlorophenol, at 1·8 μg/litre, decreased assimilation conversion efficiency in underyearling salmon. Phenol also affects immunoglobin levels, blood protein levels and tissue micro-element levels. Feeding rates are affected by phenolics. Phenolics affect oxygen consumption rates and the effect may be on uncoupling of oxidative phosphorylation with a subsequent reduction of ATP formation.Many aspects of behaviour are affected by phenolics and the phases of ‘intoxication’ leading to death have been described for fish and invertebrates.Fish detoxify phenolics by forming conjugate glucuronides and sulphates. Body burdens of phenolics varied with exposure time and exposure concentration. When fish pre-exposed to phenol are transferred to clean water, body burdens drop up to 90% after three to four hours. Depuration rates for other phenolics took longer; up to 30 days for pentachlorophenol.Little research has been done on the cycling of phenol and phenolics (other than pesticides) in aquatic ecosystems. Microbial degradation will decompose phenolics rapidly if suitable bacteria are present. Other factors affecting the loss of phenolics from aquatic ecosystems include photolysis, adsorption and dilution. Phenol entering subterranean aquifers may not dilute or degrade very quickly. In one documented case well-water levels up to 200 mg/litre were measured 18 months after a spill.     

The uptake and accumulation of Ni by Cerastoderma edule and its effect on mortality,body condition and respiration rate

The concentration of Ni in C. edule ranges from 17·8 μg/g to 53·82 μg/g with the highest concentration in the gills and mantle and the lowest in the foot and adductor muscles. The concentration does not change with either size or season.There is no significant increase in mortality even in the highest Ni concentration (100 μg/litre), nor is body condition correlated with experimental Ni concentrations. The rate of uptake of Ni (y) is described by the equation:

$\text{y=?16·903+11·674x}{}_1\text{+0·437x}{}_2$

where x₁ = Ni concentration (μg/litre) and x₂ = time (h).The respiration rates did not significantly change up to the highest Ni concentration used (1000 μg/litre).It is postulated that the main pathway for Ni uptake is through the gills, possibly through mucus sheet or transmembrane absorption, with a secondary uptake route via the viscera.C. edule may therefore be a suitable indicator species for Ni.     

Relationships between physiological stress and trace toxic substances in the bay mussel, Mytilus edulis, from San Francisco bay,California

Resident populations of Mytilus edulis from Tomales and San Francisco Bay, California, were measured for scope of growth, a physiological integration of the energy consumed by individual animals (feeding rate and assimilation efficiency) less the energy lost in metabolic processes (oxygen consumption and ammonia excretion). Scope for growth of mussels was significantly correlated (p≤ 0·05) with feeding rates. There was a significant decline in the scope for growth between the Golden Gate, at the bay's entrance and RedwoodCity in south San Francisco Bay. The scope for growth in resident M. edulis was significantly negatively correlated (p≤ 0·05) with increased environmental concentrations (from transplanted M. californianus body burden data) of the following trace elements and higher molecular weight chlorinated organic compounds: Cr, Cu, Hg (p ≤ 0·01) and Ag, Al, Zn, total chlordanes, and dieldrin. Scope for growth was significantly correlated (p ≤0·05) with body condition index (dry body weight1shell length).     

Mercury levels in some species of fish from the coast of Lebanon

The muscle tissue of 266 fish caught along the coast of Lebanon from Beirut to Tyre (85 km) were analysed for total mercury content. The mean levels for the 13 species ranged from 0·028 mg/kg of wet tissue for Siganus rivulatus to 0·0.54 mg/kg for Mullus barbatus. Whereas no significant differences (P < 0·05) in mercury levels were noted between species, in most cases a direct relationship was found between the weight or length of fish of the same species and total mercury content. Similarly, there were no significant differences (P < 0·05) between herbivore and carnivore species, nor between resident and migrant ones. All of the values obtained in the present study fall below the widely accepted limit of 0·5mg/kg of edible tissue.     

Deoxygenation and remineralization above the sediment-water interface; an in situ experimental study

An in situ chamber of volume 3881 and bottom area 0·64 m² was used to determine the flux of oxygen and inorganic nutrients across an estuarine sediment-water interface over a 65-day period. Over the first 7 days, oxygen uptake was 378 mg m^?2 day^?1 and the rates of ammonium and phosphate release were 2·22 and 0·34 mg at. m^?2 day^?1, respectively. The water became anoxic in 14 days.The rates of flux in a similar chamber containing only detritus recently settled from the water column were 371 mg m^?2 day^?1 (oxygen), 1·66 mg at. m^?2 day^?1 (ammonium) and 0 12 mg at. m^?2 day^?1 (phosphate), demonstrating that detritus contributes substantially to exchange across the sediment-water interface.The evolution of the two chambers was similar over the latter part of the experimental period. A third chamber containing only water exhibited very minor changes.The role of detritus in nutrient recycling at the sediment-water interface is discussed in relation to the productivity of shallow water bodies such as the estuary in which the experiment was conducted, which itself undergoes periodic deoxygenation during prolonged stratification. The measured flux of nitrogen across the interface was found to represent approximately 31% of the mean daily phytoplankton requirement.     

Survival of juvenile spot (Leiostomus xanthurus) exposed to bromochlorinated and chlorinated sewage in estuarine waters

The acute toxicity of chlorinated and bromochlorinated treated sewage waste was determined with spot, Leiostomus xanthurus. The halogenated sewage waste was generated in a pilot plant located at the James River Sewage Treatment Plant, Newport News, Va. The 96 h and 144 h LC50's were 0·23 mg/l (measured residual) for chlorine and 0·25 mg/l (measured residual) for bromine chloride. These concentrations are considerably higher than those which would be produced by optimal halogenation rates for disinfection or maximum superhalogenation rates permitted by pilot plant equipment and normal effluent dilution rates.     

Seasonal fluctuations and compositions of two populations of small demersal fishes on the west coast of Scotland

The soft sediment fish communities below 20 m depth were studied at two sites on the west coast of Scotland (Irvine Bay, Firth of Clyde and the Lynn of Lorne) using small meshed beam trawls. In both cases the emphasis was on the small demersal fish (<15 cm) within these communities. The Irvine Bay community was studied between May 1978 and December 1979 and the Lynn of Lorne community between February 1975 and October 1976.Twenty-seven fish species were recorded in Irvine Bay and 32 in the Lynn of Lorne. In both communities four species constituted more than 78% of the total annual abundance, two gobies (Lesueurigobius friesii and Pomatoschistus norvegicus) were high in the dominance ranking for both sites. The species abundance lists were similar for both sites (0·62 level of similarity) but the species lists for each site were different (0·36 level of similarity). The overall mean density of small demersal fish was similar for both sites (Irvine Bay = 0·045 individuals m^?2 and the Lynn of Lorne = 0·047 individuals m^?2). There were two periods of high abundance for both communities (late autumn to winter and late spring). There was, however, a low repeatability between successive years. The species richness (D) was relatively high (Irvine Bay = 1·5-3·08, Lynn of Lorne = 1·4-3·34) as was the species diversity (H′) (Irvine Bay = 1·17-1·97, Lynn of Lorne = 1·23-1·95). The proportional representation ($\text{J′}$) of each species within the community was greater in Irvine Bay ($\text{J′}$ = 0·57-0·77) than in the Lynn of Lorne ($\text{J′}$ = 0·50-0·72). Therefore these two communities of small demersal fish appeared to be similar at the community level but the way in which this was achieved was different.     

Reduced survival and condition of the bivalves Protothaca staminea and Mytilus edulis buried by decomposing bark

The bivalves Protothaca staminea and Mytilus edulis were exposed to five depths of decomposing bark from an active log transfer facility for 13–96 days in a field experiment at Auke Bay, Alaska. Survival and condition of both species was inversely related to depth and duration of bark coverage. As little as 6 cm of bark reduced survival; survival declined most rapidly between 10 and 15 cm of bark. The depths of bark under which half the animals died after 96 days of exposure were 12·8 ± 1·6 cm for P. staminea and 10·9 ± 1·5 cm for M. edulis. Interstitial water in the bark deposits had low concentrations of dissolved O₂ (2·5–5·3 mg/liter) and elevated concentrations of hydrogen sulfide (1·0–8·1 mg/liter total sulfide) and ammonia (46–131 μg-at N/liter) compared to the surface water from the control treatment. Survival of P. staminea and M. edulis was inversely related to concentrations of hydrogen sulfide and ammonia and directly related to dissolved O₂ concentrations.     

Acute toxicity of bromochlorinated seawater to selected estuarine species with a comparison to chlorinated seawater toxicity

The acute toxicity of bromochlorinated estuarine water (ca. 20%) was determined for several estuarine organisms. The most sensitive species were oysters (Crassostrea virginica, larvae and juveniles) and copepods (Acartia tonsa) with 48-h LC₅₀'s of 0·10 to 0·21 mg BrCl/litre. Palaemonetes pugio was most tolerant with a 96-h LC₅₀ of 0·70 mg BrCl/litre. The fish species tested (Menidia menidia, Brevoortia tyrannus and Leiostomus xanthurus) all had a 96-h LC₅₀ of 0·21–0·23 mg BrCl/litre.The BrCl toxicity data are compared with Cl₂ toxicity data for the same species. When the LC₅₀'s are expressed as equivalents per litre, BrCl is found to be two to four times less toxic than Cl₂. The ranking of species in terms of sensitivity is the same for both disinfectants.Some data are provided concerning the decay rates of BrCl and Cl₂ in estuarine water. BrCl was found to decay more rapidly than Cl₂ at higher ammonia levels (0·25 mg NH₄-N/litre). The question of chemical speciation is discussed with particular reference to the differential toxicities.     

Concentrations of zinc,manganese, copper,cadmium, magnesium and iron in ten species of algae and sea water from Aqaba,Jordan

Concentrations of zinc, manganese, copper, cadmium, magnesium and iron in three species of red, four species of brown and three species of green macroalgae, and also in sea water have been determined at two localities along the coast of Aqaba. Significant differences in metal concentrations were found between the various species (P<0·01). Similar significant differences were found with regard to different metals (P<0·001). Concentration factors ranged between 10² for Cd and 9·2 × 10⁴ for Fe. The difference in levels of metals between the two localities, however, was not significant (P > 0·05). Of the three groups of algae examined, rhodopytes exhibited the highest concentration power of metals.     

Behavioural responses of the bivalve Scrobicularia plana (da Costa) subjected to short-term copper (Cu II) concentrations

Short-term (6 h) behavioural responses and mortality of Scrobicularia exposed to low concentrations of copper in sea water (31%, S) have been investigated.Scrobicularia can detect copper at a concentration of 0·01 ppm. The initial response is valve closure resulting in a rapid drop in heart rate. In concentrations of 0·05, 0·01 and, to a lesser extent, 0·1 ppm copper added to sea water, the clams begin to interact with the polluted water after 2–3 h. In 0·5 ppm, the valves remain closed and the heart rate is maintained at a low level over the 6-h exposure period.Mortality increases with time in 0·5 ppm copper concentration, reaching 50% in 5–7 days. In 0·05 and 0·01 ppm, no mortality was recorded over this period.There is an increase in mantle cavity water calcium concentration after 6 h in 0·5 ppm, in contrast to 0·1, 0·05 and 0·01 ppm. Aspects of anaerobiosis, accumulation of heavy metals and survival are discussed in relation to the behaviour of Scrobicularia exposed to various copper concentrations.     

Cadmium acclimation and limb regeneration in the fiddler crab, Uca pugilator: Sex differences

After multiple autotomy in the fiddler crab, Uca pugilator, cadmium retards limb regeneration and ecdysis. To study the effects of pre-exposure to lower levels of cadmium, groups were pre-exposed to 0·1, 0·5 or 1·0 mg liter^?1 for a week prior to autotomy. Crabs were then placed in 1·0 mg liter^?1 for regeneration. Pre-exposed groups were compared with groups of crabs which had not been pre-exposed to Cd. It was found that males pre-exposed to 0·5 mg liter^?1 regenerated more rapidly in 1·0 mg liter^?1 than those not pre-exposed. This phenomenon was not observed in females, in which none of the three pre-exposure concentrations were able to accelerate regeneration in 1·0 mg liter^?1 relative to those not pre-exposed. In the pre-exposed males in which regeneration was accelerated and was comparable to control levels, no accompanying decrease of time until molting was observed. Therefore, the protective effect of pre-exposure would seem to be on the regeneration processes themselves and is not dependent on the neuroendocrine system which controls the molt cycle.     

Anionic species of V,As, Se,Mo, Sb,Te and W in the Scheldt and Rhine estuaries and the Southern Bight (North Sea)

Oxy-anionic species of V, As, Se, Mo, Sb, Te and W were measured in solution and suspension in samples obtained during several cruises in the Dutch Wadden Sea, the offshore region of the Southern Bight (North Sea) and in the estuaries of the Rhine and Scheldt. Dissolved concentrations at salinities above 34·5 × 10^?3 ( = 34·5%. S) agreed generally well with published open ocean values. It is suggested that Se speciation differs from the open ocean.In the Wadden Sea, concentrations of V, Se, Mo and Sb were linearly related to salinity (10–35 × 10^?3). The good agreement between measured and extrapolated values at a salinity of 0·5 × 10^?3 suggests conservative behaviour in the Rhine estuary (with residence time of freshwater in the order of a few days).Dissolved concentration vs. salinity plots in the Scheldt estuary (residence time 2–3 months) showed pronounced minima and maxima. These occurred in the low or medium salinity range for V, As and Sb. Linear behaviour was observed for Se and Mo (in some cases, relatively large differences between cruises were detected). Deviations from linearity in the plots are interpreted in terms of thermodynamic equilibrium conditions involving species with different solubilities (V), local input from land (As, Se, Sb, Te) and removal from solution (As), probably through coprecipitation with Fe(OH)₃.In the offshore samples, the contributions of particulate forms to the total element concentrations were small (<15%). At higher SPM concentrations (about 30 mg dm^?3), this percentage remained small for Se, Mo and Sb (<15%); it was substantial for V and As (25–50%).     

Chlorophyll distribution in continental shelf sediments off West Palm Beach,Florida and west end,Bahamas

Measurements were made of chlorophyll-a and phaeophytin-a in calcareous sediments along transects off the east coast of Florida (75–190 m) and the west coast of Grand Bahama Island (170–300 m). Solvent partitioning showed that chlorophyll-a concentrations never exceeded 0·1 mg m^?2 at either location, most as degradation products. Total pigment concentrations (chlorophyll and phaeopigments) ranged from 0·18–1·83 mg m^?2 in sediments off Grand Bahama Island and 2·50 to 20·65 mg m^?2 off West Palm Beach. Pigments, expressed per gram dry weight of sediments, increased with depth across the Florida Continental Shelf. This is probably due to differences in sediment character between near-shore and off-shore sediments.