Comparative study of cadmium levels of shellfish and finfish species

This study indicates that the concentration of cadmium in shellfish species may often be higher than it is in their environment as a result of formation of stable biological chelate complexes. This study also indicates that the concentration of cadmium in finfish species is less than the shellfish species. It was found that cadmium levels in shellfish were relatively higher in oysters and shrimps, moderately high in scallops and squids, and less in crabs and clams. It seems that cadmium levels are surprisingly elevated in shellfish than other saltwater finfish. It also seems that larger shellfish had higher Cd content levels than the smaller shellfish of the same species.     

Determination of toxic elements (mercury,cadmium, lead,tin and arsenic) in fish and shellfish samples. Risk assessment for the consumers

Although fish intake has potential health benefits, the presence of metal contamination in seafood has raised public health concerns. In this study, levels of mercury, cadmium, lead, tin and arsenic have been determined in fresh, canned and frozen fish and shellfish products and compared with the maximum levels currently in force. In a further step, potential human health risks for the consumers were assessed. A total of 485 samples of the 43 most frequently consumed fish and shellfish species in Andalusia (Southern Spain) were analyzed for their toxic elements content. High mercury concentrations were found in some predatory species (blue shark, cat shark, swordfish and tuna), although they were below the regulatory maximum levels. In the case of cadmium, bivalve mollusks such as canned clams and mussels presented higher concentrations than fish, but almost none of the samples analyzed exceeded the maximum levels. Lead concentrations were almost negligible with the exception of frozen common sole, which showed median levels above the legal limit. Tin levels in canned products were far below the maximum regulatory limit, indicating that no significant tin was transferred from the can. Arsenic concentrations were higher in crustaceans such as fresh and frozen shrimps. The risk assessment performed indicated that fish and shellfish products were safe for the average consumer, although a potential risk cannot be dismissed for regular or excessive consumers of particular fish species, such as tuna, swordfish, blue shark and cat shark (for mercury) and common sole (for lead).     

长江靖江段近岸小型渔业生物碳氮稳定同位素特征分析

长江靖江段是众多洄游性渔业生物的重要栖息地,为进一步的研究和渔业资源评估提供基础生物学资料、掌握该水域食物网结构特征,应用碳、氮稳定同位素技术测定了2016年8月在长江靖江段近岸采集的蟹类、小型鱼类、虾类等渔业生物样品的δ~(13)C值和δ~(15)N值,并由此构建了所采集的各类渔业生物的连续营养谱。结果表明:长江靖江段近岸各类生物中浮游动物的δ~(13)C值最低,为-30.34‰;其次是底栖碎屑的-30.24‰;贝类、水生植物类、鱼类和虾类居中,它们的δ~(13)C值均值分别为-29.75‰±0.75‰、-28.98‰±0.88‰、-26.74‰±2.37‰、-26.1‰±0.16‰;蟹类最高,为-25.86‰±0.74‰。水生植物类的δ~(15)N均值最低,为5.16‰±0.85‰;底栖碎屑其次,为5.58‰;贝类、鱼类、浮游动物和蟹类的δ~(15)N值均居中,δ~(15)N均值分别为8.13‰±0.31‰、11.56‰±1.59‰、12.02‰和12.51‰±1.43‰;虾类的δ~(15)N均值最高,为13.05‰±0.45‰;营养级由低到高依次为:水生植物类、底栖碎屑、贝类、浮游动物、小型鱼类、蟹类和虾类。近岸水域的小型鱼类、蟹类和虾类拥有着比较接近的食物源,生态位重叠较为明显。     

Trace elements in fish from the Savannah river near Savannah river nuclear plant

A survey of trace element residues in fish from the Savannah River near Savannah River Nuclear Plant was undertaken in 1982. Fish muscle tissue was incubated by the wet digestion method. Fifteen trace elements were determined by flame atomic absorption spectrophotometry analysi of the digests. It was found that As, Se, Mg, Hg, Ca, Zn, and Fe levels were relatively higher than Pb, Cd, Ni, Co, Cr, and Mn in all fish species. In addition, in all fish species it seems that Pb, Cd, Ni, Co, Cr, and Mn levels were relatively higher than Cs and Cu. Cs and Cu levels were negligible in all fish species analyzed. Trace element levels found in these fish species were not high enough to render them dangerous for human consumption.     

Exposure to domoic acid through shellfish consumption in Belgium

A main known culprit causing amnesic shellfish poisoning in humans is domoic acid (DA). The toxin appearance in sea waters (by counting the toxin producing algae) and consequently in shellfish is closely monitored to prevent acute intoxications with gastrointestinal symptoms and neurological signs. However it is assumed that there might be some chronic problems with repetitive exposures to the toxin in animals. In humans this is greatly unknown and it is mostly assessed by relating reported toxin episodes and representative consumption data. Although in Belgium no alarming outbreaks have been reported in recent years, different concentrations of DA have been found in shellfish samples. In this study the human acute and chronic exposure to DA through shellfish consumption was evaluated by linking the data of DA concentrations in samples collected in the scope of the National Food control program in the period 2004–2009 and consumption data obtained from the National Belgian Food Consumption Survey including 3245 adults. The found level of toxin was highest in scallops while lowest in mussels. The mean usual long-term intake of molluscs such as scallops, mussels and oysters for the whole Belgian population was from 0.10 g/day for scallops to 1.21 g/day for mussels. With average portion size estimated to be 56–108 g/day depending on the shellfish source it was calculated that less than 1% of the population would be at risk of acute intoxication. Using a medium bound approach, 5–6% of the population shows chronic exposure exceeding the tolerable daily intake of 0.075 μg/kg bw per day with scallops being the most probable toxin vector when using lower (68.5%) and medium (45.6%) bound concentrations.     

Behavior of cesium in fish tissues from Savannah River

A survey of cesium residues in fish from the Savannah River near the Savannah River Nuclear Plant was undertaken in 1983. Fish tissues, bone, fin, and muscle were incubated by the wet disgestion method for analysis. Seventeen fish samples were analyzed by flame atomic absorption spectrophotometry procedure to determine cesium content. It was found that cesium concentration levels were consistently higher in the bones and fins than in muscles of all fish species. It seems that cesium concentration levels were relatively higher in fins than in bones. Cesium concentration levels in muscle tissues were negligible in all fish species.     

Heavy metals in fish (Solea vulgaris, Anguilla anguilla and Liza aurata) from salt marshes on the southern Atlantic coast of Spain

Comparisons were made of metal concentrations in water and sediment with those in the muscle and livers of three species of fish caught in four seawater reservoirs (two in the Odiel estuary and two in the Bay of Cádiz). The concentrations of a large number of metals in the water, sediment and fish were higher in the Odiel reservoirs than in those in Cádiz. We found high metal-enrichment factors in the livers as compared to muscle (over 100 for Fe and Cu and around 5 for Zn, Ni, Cd and Pb). The three fish species showed differences in metal content. For example, eels accumulated more metals in muscle and grey mullet in the liver. The metal levels found in muscle in the three species were below the legal limits for human consumption, although Cu in the liver was above the limit in the three species taken from the Odiel reservoirs, and Zn levels in liver were over the maximum in eels from one of the Odiel marshes. Significant correlations (p<0.05) were obtained for the levels of numerous metals in water, sediment and fish.     

Variability in the edible fraction content of 60Co, 99Tc, 110mAg, 137Cs and 241Am between individual crabs and lobsters from Sellafield (north eastern Irish Sea)

We investigated the variability of anthropogenic radionuclide content of the edible fractions of individual edible crabs (Cancer pagurus L.) and European lobsters (Homarus gammarus L.) caught commercially in the Sellafield offshore area. Sixteen female and 18 male crabs and 20 female and 17 male lobsters were selected from commercial catches made between 25 May and 5 June 1997. Each gender group was selected to be within the known weight range for commercially caught crustacea from the area. Four artificial radionuclides (60Co, 110mAg, 137Cs or 241Am) were detected by gamma-spectrometry. The edible fraction content of these radionuclides between males and females for either species were not statistically significantly different. 99Tc was analysed by chemical separation and beta-counting. 99Tc concentrations in female crabs tended to be higher (172 +/- 205 (16) Bq kg-1(wet); mean +/- standard deviation (n samples)) than those in males (85 +/- 58 (18) Bq kg-1 (wet)), although this was not a statistically significant difference. For both male and female crabs, 99Tc concentrations tended to decrease with increasing whole live weights. For 99Tc in lobsters the picture is less clear. Female lobsters contained more activity (14800 +/- 7400 (20) Bq kg-1 (wet)) than males (7100 +/- 3900 (17) Bq kg-1 (wet)). The results were used to discuss the implications for sampling and monitoring.     

Distribution of trace elements in tissues of two shrimp species from the Persian Gulf and roles of metallothionein in their redistribution

This study investigates the distribution of three trace elements (Cd, Cu and Zn) in tissues (exoskeleton, abdominal muscle and hepatopancreas) of two shrimp species (Penaeus merguiensis and Penaeus semisulcatus). Special emphasis in this study was placed on evaluating the effects of storage conditions on redistribution of the elements and moreover the potential roles of metallothionein in tissue redistribution. The specimens were collected from the northern part of Persian Gulf during September 2001 and January 2002. The concentrations of metals in the tissues were measured using an Inductively Coupled Plasma-Atomic Emission Spectrophotometer (ICP-AES) and an ICP-Mass Spectrometer (ICP-MS). Metallothionein levels were determined using Differential pulse polarography. Results show a similar hierarchy for Cd and Cu concentrations among different tissues as follows: hepatopancreas>exoskeleton>muscle; and for Zn, the hepatopancreas again contained the highest levels, though there were not any significant differences in Zn concentrations between muscle and exoskeleton. Significant differences were found between the species in the case of Cd and Zn concentrations. Cd and Zn levels in P. semisulcatus were markedly higher than in P. merguiensis. In general, there were highly significant differences among the storage conditions from accumulation the selected trace elements and metallothionein in both species point of view, but in most cases, no significant differences could be observed among the fresh, refrigerated and frozen specimens of P. semisulcatus. In regards to Zn and Cu accumulation in edible (muscle) tissues of P. merguiensis, optimum conditions for frozen storage is -30 degrees C as ice-frozen, and in terms of short-term storage, 1-day refrigeration is recommended. The redistribution of Zn and Cu during the storage period can be attributed to the role of metallothionein in their transport from organ(s) to muscle during storage. The variations in pH values measured in the muscle of P. merguiensis in different storage conditions showed a similar trend with metallothionein, Zn and Cu. In contrast, it appears that cadmium is transported from muscle to the other tissues. Exoskeleton is probably one of the recipient tissues of cadmium. The inter-elemental relationships were assessed for each species, separately. A significant positive relationship was observed between the concentrations of Zn and metallothionein in P. semisulcatus, whereas in P. merguiensis, Cd concentrations decreased significantly with increasing metallothionein. Highly significant differences between the sexes in Cu and Zn contents could be detected. The differences between the sexes in the levels of Zn and Cu were significantly greater in P. semisulcatus. Highly significant size-related differences were found in the levels of Cd, Cu and metallothionein in the selected tissues of the shrimp species. Comparison between the mean concentrations of the elements in muscle tissue and existing guidelines indicate that in nearly all cases, the concentrations were well below permissible levels for human consumption. The only exception was observed regarding mean values of Cd, which was somewhat greater than some of the recommended levels.     

Metal and metallothionein content in tissues from wild and farmed Anguilla anguilla at commercial size

Metallothionein and metal content (Cd, Zn, Hg, Cu, Fe, Pb and Mn) were determined in various organs of commercially available eel (Anguilla anguilla) of similar size obtained from a local farm and from The Albufera Lake in Valencia (Spain). Farmed fish showed statistically significant higher Cd concentrations in liver and kidney whereas wild individuals had higher levels of Pb in blood and Zn in kidney. Significant positive correlations were found between metallothionein and Cd in kidney of farmed eel and between metallothionein and Cu in liver of wild ones. No statistically significant differences were found between the two populations in the concentration of any of the metals analyzed in muscle and in all instances these levels were lower than the limits established by the Spanish legislation for fish destined for human consumption.     

Comparative analysis of inorganic elements in the muscle and liver of some fish species

Four fish species were collected: brown trout, grouper, spotted tail bass, and black crappie. Fish samples were thawed and dissected. The pieces of edible muscle and liver tissues were digested in a reagent-grade nitric acid, in a constant temperature shaking-water bath at 58°C. Thirteen inorganic elements were determined by flame atomic absorption.The significant findings of this report are that inorganic elements, mercury, iron, copper, zinc, chromium, and nickel with the exception of magnesium show elevated levels in the livers than in the muscles of all the four fish species. It seems magnesium concentration levels were consistantly higher in the muscles than in the livers of all four fish species. It is found that calculations of muscle-liver ratios indicate that ratios in the range of 0.5 are preliminary indicative of environmental static conditions, whereas ratios in the range of more than one are indicative of environmental improvement.     

Distribution of organotin compounds in the bivalves of the Aegean Sea, Greece

Five bivalve species--Mytilus galloprovinciallis (Mediterranean mussels), Venus gallina (stripped venus), Modiola barbatus L. (bearded horse mussels), Pecten jacobeus (scallops) and Callista chione (hard clams)--were collected from seven areas in Aegean Sea, Greece, between August 2001 and January 2003 and analyzed for organotins (OTs). The concentrations (as geometric means) found were 17.1 ng g-1 for tributyltin (TBT), 18.8 ng g-1 for dibutytltin (DBT), 7.8 ng g-1 for monobutyltin (MBT) and 13.0 ng g-1 for triphenyltin (TPhT) (wet weight), which are at similar or lower levels than those reported worldwide. Studying OTs distribution between different bivalve species, lower concentrations were observed in mediterranean mussels, possibly due to their growth in water column (grown on sea net pens in mussel farms), in contrast to the free-ranging species, collected from fishing grounds. Concentrations of the OTs in the examined bivalves varied seasonally.     

Fractionation studies and bioaccumulation of sediment-bound heavy metals in Kolleru lake by edible fish

Kolleru lake is the largest fresh water lake in the districts of East and West Godavari of Andhra Pradesh, India. Many anthropogenic sources contribute to the heavy metal pollution in the lake and the bioaccumulation of heavy metals in fish helps in assessing the aquatic pollution. Total contents and fractionation of selected heavy metals, viz., Zn, Cu, Cd, Pb, Cr, Ni and Co were measured in sediment sample and three edible fish. The investigation aimed at revealing differences in the accumulation pattern of heavy metals in fish inhabiting sediments characterized by varying metal bioavailability. The metal concentrations were found to be greater than the background concentrations of sediments indicating the anthropogenic origin of metals. Good recovery values were obtained for metal contents in sediments and fish. Large fractions of Zn, Cd and Cu were associated with mobile fraction of sediment and showed greater bioaccumulation in fish whereas Ni and Co were least mobilisable. The results clearly indicate that the fish of Kolleru lake are contaminated with metals and not advisable for human consumption.     

Copper and zinc in four freshwater fish species from Lake Pamvotis (Greece)

Lake ecosystems are vulnerable to heavy-metal pollution. Fish samples are considered as one of the most indicative factors, in freshwater systems, for the estimation of trace metals pollution potential. Lake Pamvotis (NW Greece) is a typical Mediterranean ecosystem of great importance in regard to biodiversity and to aesthetic value. The fish species found most commonly in the lake are Cyprinus carpio, Silurus aristotelis, Rutilus ylikiensis, and Carassius gibelio. The aim of the present study is to evaluate the level of contamination of two essential heavy metals (copper and zinc) appearing at high concentrations in lake water in the above four fish species. Metal concentrations were measured by atomic absorption spectroscopy in three different tissues (muscle, liver, gonads) in order to assess the fish contamination. A two-factor analysis of variance, based on the procedure of general linear models, was employed in which fish species (four levels) and fish tissue (three levels) were examined for potential influence on Cu and Zn concentrations. Differences between level means per factor were treated using Tukey's multiple comparisons of means. The study showed that C. carpio and R. ylikiensis presented the highest metal content. Tissues analysis revealed that liver and gonads accumulated the highest levels of Cu and Zn. Metal concentration in the edible part of the examined fish (muscle) were in the safety-permissible levels for human consumption.     

苏南经济快速发展区土壤有效态镉含量影响因素及分布特征

研究了农田土壤有效态镉含量的影响因素及分布特征。结果表明：① 土壤有效态Cd含量总体较高,平均值为0.092 mg/kg,最大值高达0.354 mg/kg,且土壤Cd的平均活化率高达53%,Cd是该区主要的重金属污染物之一;②土壤表层有效态Cd含量与全Cd含量呈极显著正相关,回归分析表明该区农田土壤有效态Cd含量主要受全Cd含量的影响;③在不同经济功能区,有效态Cd和土壤Cd的活化率均以化工区为高,在不同地貌区,二者均以中部平原区最高,中部平原区Cd的活化率显著高于北部洼区;④在土壤剖面上,土壤有效态Cd含量和土壤Cd的活化率均以表层为高,表明土壤Cd的环境风险主要集中在表层20 cm。     

The use of the oxidative stress responses as biomarkers in Nile tilapia (Oreochromis niloticus) exposed to in vivo cadmium contamination

Water contaminants have a high potential risk for the health of populations. Protection from toxic effects of environmental water pollutants primarily involves considering the mechanism of low level toxicity and likely biological effects in organisms who live in these polluted waters. The biomarkers assessment of oxidative stress and metabolic alterations to cadmium exposure were evaluated in Nile tilapia, Oreochromis niloticus. The fish were exposed to 0.35, 0.75, 1.5, and 3.0 mg/l concentrations of Cd2+ (CdCl2) in water for 60 days. Fish that survived cadmium exposure showed a metabolic shift and a compensatory development for maintenance of the body weight gain. We observed a decreased glycogen content and decreased glucose uptake in white muscle. Lactate dehydrogenase (LDH) and creatine phosphokinase (CK) activities were also decreased, indicating that the glycolytic capacity was decreased in this tissue. No alterations were observed in total protein content in white muscle due to cadmium exposure suggesting a metabolic shift of carbohydrate metabolism to maintenance of the muscle protein reserve. There was an increase in glucose uptake, CK increased activity, and a clear increase of LDH activity in red muscle of fish with cadmium exposure. Since no alterations were observed in lipoperoxide concentration, while antioxidant enzymes glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) were changed in the liver and the red and white muscle of fish with cadmium exposure, we can conclude that oxygen free radicals are produced as a mediator of cadmium toxicity. Resistance development is related with increased activities of antioxidant enzymes, which were important in the protection against cadmium damage, inhibiting lipoperoxide formation.     

The effect of ageing on the bioaccessibility and fractionation of cadmium in some typical soils of China

Ingestion of contaminated soil has been recognized as an important exposure pathway of cadmium (Cd) for humans, especially for children through outdoor hand-to-mouth activities. The effect of ageing process following the input of Cd into soil on the bioaccessibility of Cd in five typical soils of China was investigated using physiologically based in vitro test in this study. A sequential extraction procedure was employed with attempt to identify the bioaccessible fraction(s) of Cd in soils. The bioaccessibility of Cd in strongly acidic (approximately pH 4.5) soils reached nearly steady levels (76.5-76.9% and 52.0-52.6% in the gastric and small intestinal phases, respectively) after a sharp decline in the first week of ageing. In contrast, the bioaccessibility of Cd in higher pH (>6.0) soils was found to be much lower (53.3-72.7% and 29.9-43.4% in gastric and small intestinal phases, respectively) and took 2 weeks of ageing to reach steady levels. The freshly spiked Cd was more labile than native Cd. The main proportion of spiked Cd was found in exchangeable Cd which was higher in strongly acidic soils (68.6-71.8%) than in higher pH soils (53.4-61.4%) at day 120 after a sharp decline to the nearly steady state in the first 1 and 2 weeks, respectively. Significant correlations between Cd bioaccessibility and either water soluble and exchangeable Cd individually, or the sum of water soluble and exchangeable Cd throughout the incubation period for all soils, indicate that these forms of Cd are likely to constitute the main proportion of bioaccessible Cd in soils.     

Health concerns of consuming cockles (Cerastoderma edule L.) from a low contaminated coastal system

Commercial and recreational harvesting of shellfish within the coastal systems is usually very extensive. Since these ecosystems are frequently subjected to contamination, namely from agricultural, urban and industrial activities, and shellfish generally display a high capacity to bioaccumulate metals, populations may be at risk in terms of toxic metal exposure as a consequence of the harvesting and ingestion of near shore coastal marine organisms. Shellfish is regularly tested for concentrations of metals and other contaminants by legal authorities for commercial purposes, but although health officials use total metal as standards of food safety, only a part of the metal accumulated in shellfish is available to be assimilated and to cause toxic effect. In order to elucidate these issues an investigation on cockles inhabiting the Aveiro estuary was conducted. Element levels in sediments and wild Cerastoderma edule from sampling areas with different levels of contamination were measured; total element burden of cockles was related to accessible fraction for assimilation (TAM); element concentrations in wild C. edule were compared to EFSA (European Food Safe Authorities), USFDA (United States Food and Drug Administration) and FSANZ (Food Standards Australia and New Zealand) maximum levels (MLs); and the amount of cockle flesh needed to be consumed to exceed provisional tolerable weekly intake (PTWI) was determined. The present work showed that although sediment metal and metalloid contamination in Aveiro estuary is low the concentration of elements in C. edule does not reflect the contamination of the sediment. Aluminium (Al) and mercury (Hg) were the less and nickel (Ni), lead (Pb), zinc (Zn) and cadmium (Cd) were the most bioaccumulated metals by cockles. Comparison of MLs from international organisations with the concentration of elements in C. edule showed that arsenic (As) and Pb exceeded standard levels. The ingestion of less than 1 kg for As and 1.5 kg for Pb of cockles would result in exceeding the PTWI threshold (0.015 and 0.025 mg kg?1 week?1 respectively) in any of the areas considered in the study. Cd and Al also appear to be limiting elements for human consumption. Indeed, consumption of more than 3.1 kg and 2.1 kg of whole cockle soft part from one of the study areas during a single week would lead to exceedance of the recommended PTWI value for Cd (0.007 mg kg?1 week?1) and Al (7 mg kg?1 week?1) respectively. The health concerns to humans from cockle consumption from Aveiro estuary are discussed.     

Assessment of marine pollution in Izmir Bay: nutrient, heavy metal and total hydrocarbon concentrations

Izmir Bay (western Turkey) is one of the great natural bays of the Mediterranean. Izmir is an important industrial and commercial centre and a cultural focal point. The main industries in the region include food processing, oil, soap and paint production, chemical industries, paper and pulp factories, textile industries and metal processing. The mean concentrations showed ranges of 0.01-0.19 and 0.01-10 microM for phosphate, 0.10-1.8 and 0.12-27 microM for nitrate+nitrite, and 0.30-5.8 and 0.43-39 microM for silicate in the outer and middle-inner bays, respectively. The TNO(x)/PO(4) ratio is significantly lower than the Redfield's ratio and nitrogen is the limiting element in the middle-inner bays. Diatoms and dinoflagellates were observed all year around in the bay and are normally nitrogen limited. Metal concentrations ranged between Hg: 0.05-1.3, Cd: 0.005-0.82, Pb: 14-113 and Cr: 29-316 microg g(-1) in the sediments. The results showed significant enrichments during sampling periods from Inner Bay. Outer and middle bays show low levels of heavy metal enrichments except estuary of Gediz River. The concentrations of Hg, Cd and Pb in the outer bay were generally similar to the background levels from the Mediterranean. The levels gradually decreased over the sampling period. Total hydrocarbons concentrations range from 427 to 7800 ng g(-1) of sediments. The highest total hydrocarbon levels were found in the inner bay due to the anthropogenic activities, mainly combustion processes of traffic and industrial activities. The concentrations of heavy metals found in fish varied for Hg: 4.5-520, Cd: 0.10-10 and Pb: 0.10-491 microg kg(-1) in Izmir Bay. There was no significant seasonal variation in metal concentrations. An increase in Hg concentration with increasing length was noted for Mullus barbatus. A person can consume more than 2, 133 and 20 meals per week of fish in human diet would represent the tolerable weekly intake of mercury, cadmium and lead, respectively, in Izmir Bay. Heavy metal levels were lower than the results in fish tissues reported from polluted areas of the Mediterranean Sea.     

Multiple stressor effects of radiation and metals in salmon (Salmo salar)

These experiments were designed to look at the cellular effects in key organs in Atlantic salmon (Salmo salar) after exposure in vivo to radiation and subtoxic levels of aluminum (Al) and cadmium (Cd), alone or in combination. Salmon (25g) were exposed to a single 0.5Gy dose of gamma-irradiation in water containing Cd, Al or Cd+Al. Three fish per group were sacrificed after 1h and the liver, pronephros, fin and gill of each was dissected. Small explants of each tissue were set up. After 2 days, the culture medium was harvested and filtered then placed on a reporter cell line for determination of stress signal activity (bystander effects). Radiation in combination with Cd and/or Al, caused bystander effects in tissues harvested from in vivo exposed salmon. The effects vary between different organs and are not consistently additive or synergistic for a given treatment. Tissue type appears to be critical. Liver cultures produce a toxic factor which is lethal to reporter cells, and therefore no liver data could be obtained. It is hoped that this stress signal response will prove to be a useful indicator of environmental stress in species inhabiting aquatic ecosystems.