“Metals in Fresh Honeys from Tenerife Island, Spain”

Ashes and contents of Zn, Cu, Fe, Cd and Pb in 140 fresh honey samples from three different areas of Tenerife Island were determined by inductively coupled plasma atomic emission spectrometry and graphite furnace atomic absorption spectrometry. A mean ash content of 0.35% has been determined. The mean Fe, Cu, Zn, Pb and Cd concentrations observed have been 3.37 mg kg⁻¹, 1.28 mg kg⁻¹, 2.83 mg kg⁻¹, 37.33 μg kg⁻¹, 4.38 μg kg⁻¹, respectively. A direct statistical correlation has been found between the Fe–Zn and Fe–Pb content, and between the Cd–Zn and Cd–Pb levels.     

Mercury and Other Mining-Related Contaminants in Ospreys Along the Upper Clark Fork River,Montana, USA

We investigated links between mining-related contaminants in river sediment and their occurrence in nestling ospreys (Pandion haliaetus) in the Clark Fork River Basin, Montana, USA. Blood and feather samples from 111 osprey chicks were collected during 4 years from nests along river sections with greatly different sediment concentrations of arsenic (As), cadmium (Cd), copper (Cu), lead (Pb), zinc (Zn), and mercury (Hg). No significant differences between river sections were found among Zn (3,150 ± 160 μg L⁻¹) and Cd (<5 μg L⁻¹) concentrations in blood. Cu, Pb, and As concentrations in blood were significantly increased in chicks from the most contaminated river sections (mean values of 298, 8.9, and 100 μg L⁻¹, respectively). Cu, Zn, and Pb concentrations increased significantly during a year of above-average river runoff combined with high suspended sediment loads in rivers. Total Hg concentrations in blood and feathers were highly correlated and depended on the geographic locations of the nests. The lowest blood concentrations of Hg were observed in the most upstream river section (mean 151 μg L⁻¹) where total sediment concentrations were increased (0.80 mg kg⁻¹). River sections with intermediate blood concentrations (mean 206 and 303 μg L⁻¹) were associated with low to intermediate sediment concentrations (0.058 and 0.46 mg kg⁻¹). The highest concentrations of Hg in ospreys (mean 548 μg L⁻¹) were observed downstream from a contaminated tributary (1–4 mg kg⁻¹ in sediment). In river sections with lower Hg concentrations in sediment, there was a negative correlation between blood Hg concentration and chick mass, presumably due to high deposition rates into growing feathers. This relationship was absent in sections of high Hg exposure. Osprey blood and feathers are suitable for monitoring Hg in aquatic ecosystems; however, responses of As, Cd, Cu, Pb, and Zn are more subtle.     

Toxicity of Cadmium for Silver Catfish <Emphasis Type="Italic">Rhamdia quelen</Emphasis> (Heptapteridae) Embryos and Larvae at Different Alkalinities

The present study evaluated the effect of waterborne Cd in eggs and larvae of silver catfish, Rhamdia quelen, at two alkalinity levels (63 and 92 mg · L⁻¹ CaCO₃): 0.5 (control), 4.5, 8, and 18 μg · L⁻¹ Cd. The fertilization rate was similar in all treatments, but the number of eggs with irregular surface was significantly higher in those exposed to 18 μg · L⁻¹ Cd and 63 mg · L⁻¹ CaCO₃. Three days after hatching survival of larvae exposed to 4.5 and 8 μg · L⁻¹ Cd and 63 mg · L⁻¹ CaCO₃ was significantly lower than that of control larvae, and 21 days after hatching survival decreased with the increase in waterborne Cd levels and total cadmium accumulation in the larvae. These significant differences and relationships were not observed in larvae maintained at 92 mg · L⁻¹ CaCO₃. Furthermore, in the lower alkalinity, a higher incidence of barbels and spinal column deformities was observed in the highest waterborne Cd concentration. At the end of the experimental period, 21 days after hatching, larval survival rate, length, weight, head height, membranous layer thickness, and biomass decreased with the increase in waterborne Cd levels in the lower alkalinity. However, these relationships were not observed in larvae maintained at 92 mg · L⁻¹ CaCO₃. The percentage specific growth rate was lower in larvae exposed to the highest waterborne Cd concentration at 63 mg · L⁻¹ CaCO₃. These results suggest that alkalinity of 92 mg · L⁻¹ CaCO₃ reduces waterborne Cd toxicity in silver catfish larvae.     

Protective Effect of High Alkalinity Against the Deleterious Effects of Chronic Waterborne Cadmium Exposure on the Detection of Alarm Cues by Juvenile Silver Catfish (<Emphasis Type="Italic">Rhamdia quelen</Emphasis>)

The objective of the present study was to analyze the effect of chronic cadmium (Cd) exposure at two alkalinity levels (63 and 92 mg l⁻¹ CaCO₃) on the antipredatory behavior of juvenile silver catfish (Rhamdia quelen) exposed to conspecific skin extract and predator odor. At an alkalinity of 63 mg l⁻¹ CaCO₃, 30 days of exposure to either 4.5 or 8.0 μg l⁻¹ Cd impaired the catfish’s antipredatory response to alarm cues. However, silver catfish exposed to 4.5 μg l⁻¹ Cd at an alkalinity of 92 mg l⁻¹ CaCO₃ responded to skin extract and predator odor. In catfish exposed to 8.0 μg l⁻¹ Cd at the same alkalinity, only the number of feeding bites decreased, and this occurred only for specimens exposed to predator odor. Our results show that higher alkalinity protected against the deleterious effects of Cd on alarm cue detection but only in the larvae exposed to the lowest waterborne Cd level.     

Development of an improved rapid enzyme inhibition bioassay with marine and freshwater microalgae using flow cytometry

A rapid toxicity test based on inhibition of esterase activity in marine and freshwater microalgae (Selenastrum capricornutum, Chlorella sp., Dunaliella tertiolecta, Phaeodactylum tricornutum, Tetraselmis sp., Entomoneis cf. punctulata, Nitzschia cf. paleacea) was developed using flow cytometry. Uptake of fluorescein diacetate (FDA) was optimized for each species by varying the substrate concentration, incubation time, and media pH. Propidium iodide (PI) was utilized to assess membrane integrity. The optimized FDA/PI staining procedure was then used to assess the toxicity of copper in short-term exposures (1–24 h). Esterase activity was a sensitive indicator of copper toxicity in S. capricornutum and E. cf. punctulata. As copper concentrations increased, esterase activity decreased in a concentration-dependent manner. The 3- and 24-h EC₅₀ values (based on mean activity states) were 112 μg Cu L⁻¹ (95% confidence limits 88–143) and 51 μg Cu L⁻¹ (95% confidence limits 38–70) for S. capricornutum and 47 μg Cu L⁻¹ (95% confidence limits 43–51) and 9.1 μg Cu L⁻¹ (95% confidence limits 7.6–11) for E. cf. punctulata, respectively. This enzyme inhibition endpoint showed similar sensitivity to chronic growth rate inhibition in E. cf. punctulata (48-h and 72-h EC₅₀ values of 17 and 18 μg L⁻¹, respectively) but was less sensitive compared to growth for S. capricornutum (48-h and 72-h EC₅₀ values of 4.9 and 7.5 μg L⁻¹, respectively). For the other five species tested, inhibition of FDA fluorescence was relatively insensitive to copper, even at copper concentrations that severely inhibited cell division rate. These short-term bioassays that detect sublethal endpoints may provide a more rapid and cost-effective way of monitoring contaminant impacts in natural waters. Received: 2 July 2000/Accepted: 15 December 2000     

Intercomparison Studies on Distribution and Coassociations of Heavy Metals in Liver, Kidney, and Muscle of Harbor Porpoise, Phocoena phocoena, from Southern Baltic Sea and Coastal Waters of Denmark and Greenland

The concentrations of selected metals such as Cd, Pb, Cu, Zn, Cr, Ni, Mn, and Fe were determined in liver, kidney, and muscle of harbor porpoise (Phocoena phocoena) from three geographical regions, i.e., the Baltic Sea and Danish and Greenland coastal waters. The concentrations of Cd in liver and kidney increased with age of the specimens analyzed. Significant interspatial variations in both hepatic and renal levels of Cd were also observed. Average hepatic levels of Cd in Baltic, Danish, and Greenland specimens were (age range) 0.05–0.09, 0.12–0.25, and 20.6–51.6 μg g⁻¹ dry weight, respectively. Such values for renal Cd were as follows: 0.55–0.71, 0.14–1.84, and 0.55–94.3 μg g⁻¹ dry weight. In contrast to Cd, concentrations of Cu in the liver and kidney of specimens from Baltic, Danish, and Greenland areas did not indicate such great interspatial variability. The average hepatic values amounted to (age range) 14.1–15.5, 22.1–63.6, and 16.3–25.9 μg g⁻¹ dry weight, and kidney contained on the average 7.83–8.80, 11.7–16.2, and 11.1–15.7 μg Cu g⁻¹ dry weight, respectively. The higher levels of hepatic and renal Cd in Greenland specimens than in Baltic ones could be explained by different food composition in the area studied. Baltic porpoises mainly feed on fish (cod, plaice) containing extremely low levels of muscle Cd, but an important diet component of Greenlandic individuals is squid, characterized by elevated levels of Cd. Received: 22 May 2001/Accepted: 11 November 2001     

A Rapid Radiochemical Bacterial Bioassay to Evaluate Copper Toxicity in Freshwaters

A rapid, highly sensitive bacterial bioassay to determine copper toxicity in freshwaters was developed based on the inhibition of cellular assimilation of radiolabeled glucose. The test used a copper-sensitive bacterium isolated from a freshwater stream. Employing sensitive radiochemical techniques enabled environmentally relevant concentrations of the test bacterium (10⁵ cells mL⁻¹) and a short incubation period (4 hours) to be used, which minimized the potential for changes in copper speciation during the test. The 4-hour median effective concentration (EC₅₀) for inorganic copper at pH 7.5 in synthetic freshwater was 0.6 μg L⁻¹ (95% confidence limits 0.4 to 1.0 μg L⁻¹). This compared well with chronic growth inhibition of this bacterium in minimal medium (48-hour EC₅₀ of 0.9 μg L⁻¹ [95% confidence limits 0.7 to 1.0 μg L⁻¹ ]). MINEQL + software (Environmental Research Software) was used to calculate copper (II) ion concentrations in synthetic freshwater at pH 7.5, giving an EC₅₀ value of pCu²⁺ 8.8. However, using nitrilotriacetic acid metal-ion buffers (Cu-NTA), 50% inhibition occurred at a pCu²⁺ of 9.7, suggesting this bacterium was markedly more inhibited by copper in these Cu²⁺-buffered solutions. This may indicate that the Cu-NTA species was contributing to toxicity. The radiochemical bioassay was evaluated further using freshwater samples from both copper-impacted and pristine environments. Measured EC₅₀ values ranged from 3.4 to 34.0 μg L⁻¹ inorganic copper and were strongly correlated with dissolved organic carbon (DOC) concentrations (r = 0.88, p < 0.05).     

Mortality, Preference, Avoidance, and Activity of a Predatory Leech Exposed to Cadmium

The effects of cadmium on the hatching success of the cocoons of the freshwater predatory leech Nephelopsis obscura were examined together with the survivorship of hatchlings, changes in 96-h LC₅₀ with biomass, preference-avoidance responses and changes in activity. The 96-h EC₅₀ for cocoons was 832.6 μg Cd/L with a decreasing bounded monotonic function best describing hatchling success as a function of Cd concentration. Exposure of cocoons to Cd had a highly significant effect on post-hatchling survivorship with survivorship of hatchlings from the 0–500-μg Cd/L concentrations not significantly different from each other but higher than survivorship of hatchlings from cocoons exposed to 1,000–4,000 μg Cd/L. Resistance to acute Cd toxicity, measured as LC₅₀, increased with leech biomass. In preference-avoidance tests large leeches (>450 mg) spent more time in 100- and 200-μg Cd/L than in control water or in 50-μg Cd/L, while small leeches (<250 mg) spent more time in 200-μg Cd/L compared to control water or 50–100-μg Cd/L. Leeches exposed to 100- and 200-μg Cd/L exhibited a significant decrease in activity compared to the leeches in the control and 50-μg Cd/L treatments. Received: 14 February 1996/Revised 24 June 1996     

A Preliminary Study on Metal and Nutrient Concentrations in Running Water Systems in Southern New Caledonia

Metal and nutrient concentrations were measured in five running water sampling sites of New Caledonia. Metal concentrations were homogeneous (Ni; 22.7–50.6 μg L⁻¹) or not (Fe; 37–749 μg L⁻¹). Concentrations of Ni, Cr, Fe were high, including high dissolved fractions (up to 47.8, 70.8 and 417 μg L⁻¹, respectively). Concentrations of anthropogenic metals (Ag, As, Cd, Cu, Pb, Sb, V, Zn) were low (maximum: total Cu, 0.6 μg L⁻¹). The contamination of waters is presumably due to soil weathering and mining activities. Metal concentrations and phosphate depletion (<0.04 μmol L⁻¹) suggest constrained conditions for the development of aquatic life.     

Distribution patterns of metals contamination in sediments based on type regional development on the intertidal coastal zones of the Persian Gulf, Iran

This study was performed to determine the variation of metals concentrations (Pb, Cd, Zn, and Cu) in surface sediments based on type region development from ten sites on the intertidal coastal zone of the Persian Gulf, Iran. The metals concentrations in surface sediments varied from 0.86 to 180.78 μg g⁻¹ for Pb, 0.61 to 6.48 μg g⁻¹ for Cd, 5.99 to 44.42 μg g⁻¹ for Zn, and 3.01 to 43.33 μg g⁻¹ for Cu. The quality of the sediments was evaluated based on sediment quality guidelines (effects range-low (ERL) and effects range-medium (ERM) indexes. Biological effects criteria suggest that metals concentrations in sediments were lower than ERM for all sites, but for some sites metals concentrations in sediments were higher than ERL. The present results support the concept that human activities in each region could be a major source of metals pollution input in the aquatic environment.     

Effect of Lindane on the Clearance Rate of Daphnia magna

The impact of the insecticide lindane (γ-hexachlorocyclohexane) on the clearance rate (CR) of Daphnia magna was investigated using artificial beads. CR (24-h EC₅₀: 65 μg L⁻¹) was found to be a more sensitive endpoint than acute lethality for D. magna (48-h LC₅₀: 516 μg L⁻¹). The onset of the effect was rapid; after 2 h of exposure to approximately 241 μg L⁻¹ of lindane a significant decrease in CR was observed. Daphnids recovered rapidly after transfer to clean water; after 24 h of exposure to approximately 250 μg L⁻¹ lindane, transfer into clean water resulted in recovery to 80% of control levels within 2 h and complete recovery within 24 h. Received: 6 September 1998/Accepted: 6 December 1998     

Uptake and Elimination of Lead, Zinc, and Copper by Caddisfly Larvae (Trichoptera: Hydropsychidae) Using Stable Isotope Tracers

Stable isotopes of Pb, Zn, and Cu were used in laboratory experiments to determine the uptake and elimination of these metals by stream-dwelling caddisfly (Trichoptera: Hydropsychidae) larvae. For Pb and Cu, larvae were exposed to environmentally realistic levels (2.5 and 4.5 μg · L⁻¹, respectively) of one isotope for 9 days followed by a 9-day exposure to either the same isotope, to a second stable isotope of the same metal, or to RW containing no added isotope (two phases in total). For zinc, the exposure concentration was 15 μg · L⁻¹, and the experiment lasted for a total of 27 (i.e., three phases) rather than 18 days to see if uptake and elimination changed during the extended time period. The uptake clearances (k_u) determined for the various metals averaged 7.8, 1.4, and 0.6 L · g dw⁻¹ · d⁻¹ for Pb, Zn, and Cu, respectively, if the total metal concentration in the water was used in the calculations. The clearance rate constants (k_e) were less variable, averaging 0.15 d⁻¹ for Pb, 0.22 d⁻¹ for Zn, and approximately 0.1 d⁻¹ for Cu and were similar in both the presence (i.e., elimination) and absence (i.e., depuration) of metal in the water. These values are also comparable with those reported in the literature for other aquatic invertebrates. The use of stable isotopes thus allowed simultaneous measurement of uptake and clearance (elimination and depuration) of these metals at environmentally realistic concentrations and could be of great benefit for determining partitioning, assimilation efficiency, and pathways of these and other metals in the environment.     

Toxicity Testing of Waterborne Mercury with Red Sea Bream (<Emphasis Type="Italic">Pagrus major</Emphasis>) Embryos and Larvae

Acute toxicity tests revealed that, in red sea bream (Pagrus major) embryos, 24 and 48 h LC₅₀ values of waterborne HgCl₂ were 67.3 and 39.1 μg Hg²⁺ L⁻¹. In larvae, 48, 72 and 96 h LC₅₀ values were 41.9, 36.1 and 34.8 μg Hg²⁺ L⁻¹, respectively. Sub-chronic toxicity tests indicated that mercury concentrations ≥20 μg Hg²⁺ L⁻¹ decreased hatching success, increased mortality and induced teratogenicity in embryos and larvae. The NOEC, LOEC and MATC values were 8.0, 16.3 and 11.4 μg Hg²⁺ L⁻¹ for hatching success, mortality and teratogenicity; while those were 27.0, 36.9 and 31.6 μg Hg²⁺ L⁻¹ for body length and specific growth rate, respectively.     

Trace Elements Contamination in Coral Reef Skeleton,Gulf of Mannar,India

Coral samples were collected from Kurusadi, Shingle and Appa islands of Gulf of Mannar for analyzing the trace elements. The mean concentrations in the coral reef skeleton ranges from 0.19 to 0.62  μg g⁻¹ for Fe, from 6.71 to 15.6 μg g⁻¹ for As, from 0.28 to 1.31 μg g⁻¹ for Cd, from 0.56 to 5.29 μg g⁻¹ for Co, from 7.25 to 22.34 μg g⁻¹ for Cr, from 0.63 to 5.08 μg g⁻¹ for Cu, from 98.38 to 138 μg g⁻¹ for Mn, from 0.18 to 2.53 μg g⁻¹ for Ni, from 0.18 to 4.56 μg g⁻¹ for Pb and from 44 to 135.25 μg g⁻¹ for Zn. The factor analysis revealed the source of trace elements accumulation in the coral skeleton particularly Mn from detrital inputs and Cd from anthropogenic sources. This paper also highlights the nature of trace elements available in coral skeleton.     

Accumulation of Lead,Zinc, and Cadmium in a Wild Population of <Emphasis Type="Italic">Clethrionomys glareolus</Emphasis> from an Abandoned Lead Mine

Lead, zinc, and cadmium were determined in a range of tissues from wild populations of bank voles (Clethrionomys glareolus) trapped on an abandoned metalliferous mine site and a reference site. Estimated dietary intakes indicated that animals were exposed to elevated levels of all three metals at the mine site, and this was generally reflected in metal residues in body tissues. Lead concentrations were significantly higher in all tissues of animals from the mine compared to the reference site, while Cd was higher only in the kidney. There was evidence of age-accumulation (using total body weight as an index of age) of Cd in both the liver and kidney of mine site animals but no evidence of such accumulation of lead in bone. In contrast to Cd and Pb, Zn was lower in the tissues of mine site animals compared to the reference site. Based on critical tissue concentrations, the ecotoxicological risk to a wild population of bank voles (Clethrionomys glareolus), associated with total substrate levels of 1 μg g⁻¹ dry weight Cd and 700 μg g⁻¹ dry weight Zn at this mine site is negligible, but that associated with 4000 μg g⁻¹ dry weight Pb may be considered significant. Received: 28 January 2002/Accepted: 29 July 2002     

Bioaccumulation of Toxic Metals (Cd and Cu) by <Emphasis Type="Italic">Groenlandia densa</Emphasis> (L.) Fourr.

In this study, Groenlandia densa (L.) Fourr. (opposite-leaved pondweed), was exposed to prepared stock solution of cadmium and copper with 1.0, 3.0, 5.0 and 7.0 mg L⁻¹ concentration in certain periods (24, 48, 72 and 96 h) and changing amount of accumulation of plants in depending on time and concentration was measured by atomic absorption spectrophotometer. The results show that under experimental conditions, G. densa (L.) Fourr. proved to be a good accumulator of Cd and Cu. Removal of the metals from solution was fast in the first 4 days. The accumulation of Cd and Cu increased with the initial concentration and also with time. The highest concentrations of each trace element accumulated in opposite-leaved pondweed tissues were 1,955 μg Cd g⁻¹, 6,135 μg Cu g⁻¹ after 4 days. The maximum values of bioconcentration factor (BCF) were found for Cd and Cu 724 and 1,669, respectively. BCF values for Cd and Cu increased with time.     

Heavy Metal Levels in Suspended Sediments, Crassostrea gigas, and the Risk to Humans

Wild Pacific oyster (Crassostrea gigas) and sediment, both resuspended and suspended (RSS) samples (<53 μm), were collected over an 8-month period from a coastal estuary in Baynes Sound, BC, Canada. Stable isotope analysis (δ¹³C, δ¹⁵N) was used to determine, first, if RSS sediments was an important dietary source to C. gigas and, second, if so, whether it served as a significant dietary exposure route for Cd, Cu, Pb, and Zn. Although RSS sediments were high in trace metals such as Cd, Pb, Zn, and notably Cu, stable isotope signatures for oyster tissues did not correspond to those of RSS sediments. These results indicate that RSS sediments are not a significant source of metal to the oysters. In addition, we compared the potential risk to humans ingesting C. gigas with levels of Cd, Cu, Pb, and Zn from this study to the current Agency for Toxic Substances and Disease Registry (ATSDR) chronic oral minimal risk levels (MRLs) using current Canadian consumption guidelines of three oysters/week. Cu, Pb, and Zn levels were below MRL levels, with Cd exceeding the recommended 0.2 μg/kg/day MRL level fourfold. Total daily intake levels (TDI) for Cd were additionally calculated and either reached or exceeded the Food and Agriculture Organization/World Health Organization (FAP/WHO) reference dose of 1 μg/kg/day for Cd consumption in Canadians. Our results indicate that the current Canadian Cd consumption guidelines do not protect individuals consuming the maximum recommended levels of wild oysters.     

Metal Concentrations in the Groundwater in Birjand Flood Plain, Iran

The objective of the present study was to investigate the concentration of metals (cadmium, lead, chromium, zinc, copper, and iron) were measured in groundwater at 30 sites from the Birjand flood plain of eastern Iran during the November 2010; identify any relationships between metals and pH, total hardness. Metal concentrations in the groundwater samples were decreased in sequence of Zn > Fe > Cu > Cr > Pb > Cd, respectively. The results showed that the overall mean concentrations of Cd, Pb, and Cr were at 0.000, 0.023, and 0.049 mg l⁻¹, respectively. The mean concentration of Cu, Zn, and Fe were 0.109, 0.192, and 0.174 mg l⁻¹, respectively. Results also indicated that there were correlations among Cd, Cu, and Zn metals.     

Temporal Variation of Metals in Water,Sediment and Tissues of the European Chup (<Emphasis Type="Italic">Squalius cephalus</Emphasis> L.)

The aim of this study was to analyze seasonal variation of levels of Chromium (Cr), Manganese (Mn), Nickel (Ni), Copper (Cu), Zinc (Zn), Cadmium (Cd) and Lead (Pb) in water, sediment and tissues of Squalius cephalus (L., 1758) taken from five different stations chosen at Yamula Dam Lake (Kayseri, Turkey). Concentrations of metals were generally sorted as water<tissue<sediment. The highest concentration of metals in water was observed in the samples taken in the summer (Mn, 1.04 ± 0.15 mg L⁻¹; Ni, 0.42 ± 0.12 mg L⁻¹; Cu, 1.25 ± 0.88 mg L⁻¹; Zn, 3.61 ± 1.53 mg L⁻¹; Pb, 0.58 ± 0.09 mg L⁻¹). While the highest Zn (24.85 ± 21.82 μg g⁻¹) and Pb (10.89 ± 4.2 μg g⁻¹) concentrations in sediment were observed in the winter samples, the highest Mn concentration (167.2 ± 99.37 μg g⁻¹) was observed in the summer. Cd pollution was determined in sediment according to international criteria. The highest metal concentration in tissues was generally observed in the liver and the other tissues; following liver were gills and muscles. In liver tissues, while the highest accumulation of Zn (110.34 ± 13.1) and Mn (22.5 ± 14.85 μg g⁻¹), which are essential for the body, were observed in the winter, Pb (22.58 ± 7.83 μg g⁻¹) and Cd (11.77 ± 7.83 μg g⁻¹), which are toxic, were found to be higher in the summer. Also, concentrations of Mn, Cd and Pb in muscle tissues were found to be above the limits permitted.     

The Potential for Chromium to Affect the Fertilization Process of Chinook Salmon (Oncorhynchus tshawytscha) in the Hanford Reach of the Columbia River, Washington, USA

The Hanford Nuclear Reservation in south central Washington was claimed by the federal government as a site for the production of plutonium. During the course of production and operation of the facilities at Hanford, radionuclides and chromium were discharged directly into the river and also contaminated the groundwater. This study was designed to assess the effects of chromium (Cr) on Chinook salmon (Oncorhynchus tshawytscha) fertilization under exposure conditions similar to those of the Hanford Reach of the Columbia River. Chinook salmon gametes were exposed to aqueous Cr concentrations ranging from 0 to 266 μg Cr l⁻¹. The current ambient water-quality criteria (AWQC) established for the protection of aquatic life (United States Environmental Protection Agency [USEPA] 1986) is 11 μg Cr l⁻¹. Cr has been measured in pore water from bottom sediments of the Columbia River at concentrations >600 μg Cr l⁻¹. Under exposure conditions designed to closely mimic events that occur in the river, the fertilization of Chinook salmon eggs was not affected by concentrations of Cr ranging from 11 to 266 μg Cr l⁻¹. Data suggest that the instantaneous nature of fertilization likely limits the potential effects of Cr on fertilization success. As a result, the current AWQC of 11 μg Cr l⁻¹ is most likely protective of Chinook salmon fertilization.