Identification of the toxic agent in metal-contaminated sediments from Manitouwadge Lake, Ontario, using toxicity–accumulation relationships in Hyalella azteca

1997 ◽  
Vol 54 (5) ◽  
pp. 1055-1063
Author(s):  
U Borgmann ◽  
W P Norwood
Keyword(s):  
Copper Toxicity ◽  
Lake Ontario ◽  
Contaminated Site ◽  
Laboratory Animals ◽  
Copper Accumulation ◽  
Zinc Toxicity ◽  
Metal Availability ◽  
Growth Reduction ◽  
Short Term ◽  
Toxic Agent

Toxicity of sediments from Manitouwadge Lake, Ontario, to Hyalella correlated closely with bioaccumulation of zinc but not copper. Bioaccumulation in 1-week exposures was sufficient to infer chronic zinc toxicity. Close similarity between toxicity-accumulation relationships from Manitouwadge Lake and those obtained from zinc-spiked Hamilton Harbour sediments indicate that toxicity is due to zinc itself and not some other chemical that correlates with zinc in sediments. Sediment concentrations of zinc, on the other hand, are unreliable indicators of effects; toxicity was not highest in sediments from the most contaminated site. Copper accumulation was insufficient to cause short-term (1-week) toxicity. Chronic copper toxicity cannot be predicted from bioaccumulation, but the absence of a significant growth reduction, which is specific to copper, strongly suggests that the contribution of copper to chronic toxicity was minimal. Body concentrations of zinc and copper in wild animals from contaminated lakes (in contrast to laboratory animals exposed to sediments from those lakes) are not reliable indicators of metal toxicity, either because these amphipods have adapted to contaminated conditions or because they survive in selected microhabitats with reduced metal availability.

Toxicity and accumulation of zinc and copper in Hyalella azteca exposed to metal-spiked sediments

1997 ◽  
Vol 54 (5) ◽  
pp. 1046-1054 ◽  
Author(s):  
U Borgmann ◽  
W P Norwood
Keyword(s):  
Chronic Toxicity ◽  
Sediment Toxicity ◽  
Copper Toxicity ◽  
Hyalella Azteca ◽  
Gut Contents ◽  
Copper Accumulation ◽  
Zinc Toxicity ◽  
Short Term ◽  
Spiked Sediment ◽  
The Relationship

The relationship between zinc and copper toxicity in Hyalella azteca and accumulation from metal-spiked sediments was determined for future use in identifying sites where these metals contribute to sediment toxicity. Both zinc and copper accumulation increased rapidly with increasing sediment concentrations, showing no evidence of saturation as seen in waterborne exposures. Zinc accumulation from zinc spiked sediments was substantial, even at concentrations below those causing chronic toxicity, and body concentrations can readily be used to infer chronic toxicity. Chronic toxicity in spiked sediment exposures occurred at excess (above background) body concentrations twice as high as in waterborne exposures, possibly as a result of zinc in gut contents. In contrast, chronic copper toxicity occurred at body concentrations lower than those observed in waterborne exposures. Furthermore, body copper at low sediment exposures was independent of copper in sediment. Body copper concentrations can be used to infer short-term (1-week) toxicity but not chronic toxicity. Copper, but not zinc, caused a reduction in growth, even at concentrations below the 4-week LC25. Reduced growth can, therefore, be used to differentiate between chronic copper and zinc toxicity in sediments.

Animal models of chronic pesticide neurotoxicity

2007 ◽  
Vol 26 (4) ◽  
pp. 321-332 ◽  
Author(s):  
Virginia C Moser
Keyword(s):  
Cognitive Disorders ◽  
Laboratory Animals ◽  
Future Research ◽  
Cholinesterase Inhibition ◽  
Short Term ◽  
Routes Of Administration ◽  
Carbamate Insecticides ◽  
Short Term Exposure ◽  
Pesticide Exposures

There is a wealth of literature on neurotoxicological outcomes of acute and short-term exposure to pesticides in laboratory animals, but there are relatively few studies of- long-term exposure. Many reports in the literature describing `chronic' exposures to pesticides are, in fact, as short as five days and rarely longer than three months. Furthermore, routes of administration range from subcutaneous to dietary. Doses used in many of the studies produce signs of acute or overt toxicity. In contrast, human symptoms have been reported following exposures that are prolonged and often without obvious toxic effects. A survey of the literature was conducted to identify rodent studies with neurobehavioral and neurophysiological endpoints of pesticide exposures lasting 30 days or longer. This survey indicated that the majority of studies concentrate on cholinesterase inhibitors (organophosphorus and carbamate insecticides). Various neuromotor, cholinergic, physiological, affective and cognitive disorders were reported at doses producing cholinesterase inhibition; however, there were a fewer effects at non-inhibiting doses. Other classes of pesticides produced similar effects, with the exception of cholinergic signs. In many studies, the changes were subtle, which may correspond to the nonspecific changes in psychomotor and cognitive function reported in humans. It appears, then, that the data from animal and human pesticide exposures are generally comparable, but the specific outcomes are influenced by many experimental differences. Future research should concentrate on analogous exposures and outcomes to facilitate interpretation. Human & Experimental Toxicology (2007) 26, 321—331

Effect of Copper Toxicity on Root Morphology, Ultrastructure, and Copper Accumulation in Moso Bamboo (Phyllostachys pubescens)

2014 ◽  
Vol 69 (9-10) ◽  
pp. 399-406 ◽  
Author(s):  
Junren Chen ◽  
Danli Peng ◽  
Mohammad Shafi ◽  
Song Li ◽  
Jiasen Wu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Root Morphology ◽  
Copper Toxicity ◽  
Dry Weight ◽  
Moso Bamboo ◽  
Copper Accumulation ◽  
Root Surface Area ◽  
Phyllostachys Pubescens ◽  
Root Tips ◽  
Effect Of Copper

Abstract A hydroponic culture experiment was conducted to study the effect of copper toxicity on root morphology, ultrastructure, and copper accumulation in Moso bamboo (Phyllostachys pubescens). Root ultrastructure of Moso bamboo was studied by transmission electron microscopy and scanning electron microscopy. Application of 200 μM Cu resulted in an accumulation of 810 mg kg-1 dry weight and 91 mg kg-1 dry weight Cu in roots and shoots, respectively. The majority of the plants did not survive the application of 400 μM Cu. Biomass production declined consistently with application of each additional increment of Cu. Root growth was more severely inhibited than shoot growth. Cu adversely affected the root morphology of the plants, however, root surface area and number of root tips increased slightly at low levels of Cu. Root cell ultrastructure and organelles changed significantly under Cu stress, in particular, cell walls, mitochondria, and xylem parenchyma were affected.

Short-Term Changes of Metal Availability in Soil. Part I: Comparing Sludge-Amended With Metal-Spiked Soils

2012 ◽  
Vol 63 (2) ◽  
pp. 199-208 ◽  
Author(s):  
T. Natal-da-Luz ◽  
G. Ojeda ◽  
M. Costa ◽  
J. Pratas ◽  
R. P. Lanno ◽  
...  
Keyword(s):  
Metal Availability ◽  
Short Term

scholarly journals Growth dynamic on a co-cultivation of two Chlorophyta microalgae exposed to copper

2021 ◽  
Vol 33 ◽  
Author(s):  
Rafael Barty Dextro
Keyword(s):  
Growth Parameters ◽  
Copper Toxicity ◽  
High Growth ◽  
Single Species ◽  
High Growth Rate ◽  
Toxic Agent ◽  
Continuous Increase ◽  
Essential Nutrient ◽  
Unialgal Culture ◽  
Great Relevance

Abstract: Aim Copper is an essential nutrient for the phytoplankton, but it can also act as a toxic agent, depending on its concentration. Considering the continuous increase of this metal in the natural aquatic ecosystems, understanding its actions in co-cultivation scenarios is of great relevance. Experiments with the combination of different species resemble more accurately the natural conditions, in contrast of results obtained in single-species tests, which cannot be directly used to describe observed effects on the environment. Methods Therefore, growth parameters were investigated and compared on the co-cultivation of Chlorella sorokiniana and Kirchneriella obesa and their separate cultures exposed to three different free copper concentrations (control 6x10-9, intermediate 2x10-7 and high 1.5x10-6 mol.L-1 Cu2+). Results C. sorokiniana registered more cells in the control of the unialgal culture while K. obesa had higher cell density in the control of the co-cultivation. Growth rates decreased with the increment of copper in the unialgal conditions. However, both species maintained a high growth rate in the co-cultivation intermediate copper concentrations. Biovolume varied despite the cultivation method, being strongly related to the metal’s concentration. The maximum photosynthetic efficiency decreased in higher copper. Conclusions According to the results observed, no competitive exclusion occurred and both species were affected by copper in unialgal and co-cultivation conditions, with K. obesa being favored by the co-cultivation, which seems to have an attenuation effect on copper toxicity until intermediate concentrations. Ecologically, the results suggest that communities deal better with the toxic effects caused by intermediate copper concentrations than single-species cultures.

scholarly journals Responses of an abyssal meiobenthic community to short-term burial with crushed nodule particles in the South-East Pacific

2018 ◽  
Author(s):  
Lisa Mevenkamp ◽  
Katja Guilini ◽  
Antje Boetius ◽  
Johan De Grave ◽  
Brecht Laforce ◽  
...  
Keyword(s):  
Deep Sea ◽  
Experimental Studies ◽  
Copper Toxicity ◽  
Depth Interval ◽  
The South ◽  
Short Term ◽  
In Situ Experiment ◽  
Mining Operations ◽  
East Pacific ◽  
Undisturbed Sediments

Abstract. Increasing industrial metal demands due to rapid technological developments may drive the prospection and exploration of deep-sea mineral resources such as polymetallic nodules. To date, the potential environmental consequences of mining operations in the remote deep sea are poorly known. Experimental studies are scarce, especially with regard to the effect of sediment and nodule debris depositions as a consequence of seabed mining. To elucidate the potential effects of the deposition of crushed polymetallic nodule particles on abyssal meiobenthos communities, a short (11 days) in situ experiment at the Peru Basin in the South East Pacific Ocean was conducted. We covered abyssal, soft sediment with approx. 2 cm of crushed nodule particles and sampled the sediment after eleven days of incubation at 4200 m water depth. Short-term ecological effects on the meiobenthos community were studied including changes in their composition and vertical distribution in the sediment as well as nematode genus composition. Additionally, copper burden in a few similar-sized, but randomly selected nematodes was measured by means of µ-X-ray fluorescence. At the end of the experiment, 46 ± 1 % of the total meiobenthos occurred in the added crushed nodule layer while abundances decreased in the underlying 2 cm compared to the same depth-interval in original, undisturbed sediments. Densities and community composition in the deeper 2–5 cm layers remained similar in covered and undisturbed sediments. The migratory response into the added substrate was particularly seen in polychaetes (73 ± 14 %, relative abundance across all depth layers) copepods (71 ± 6 %), nauplii (61 ± 9 %) and nematodes (43 ± 1 %). While the dominant nematode genera in the added substrate did not differ from those in underlying layers or the undisturbed sediments, feeding type proportions in this layer were altered with a 9 % decrease of non-selective deposit feeders and an 8 % increase in epistrate feeders. Nematode tissue copper burden did not show elevated copper toxicity resulting from burial with crushed nodule particles. The results indicate that short-term substrate burial requires special attention with regard to ecological consequences of mineral extraction in the deep-sea.

Carcinogenicity of Chemicals: The Weight of Evidence

1988 ◽  
Vol 7 (5) ◽  
pp. 411-418 ◽  
Author(s):  
R.L. Carter
Keyword(s):  
Epidemiological Data ◽  
Environmental Chemicals ◽  
Laboratory Animals ◽  
Weight Of Evidence ◽  
Epidemiological Methods ◽  
Short Term ◽  
Clear Dose Response ◽  
Dose Levels

. The evidence discussed here is derived from epidemiology, long-term bioassays in laboratory animals, and predictive short-term tests. Epidemiological data are obtained directly from human studies and are most compelling when hey demonstrate a large relative risk and a clear dose-response in association with a distinctive umour type. Exposure to a suspected carcinogen and the doses involved are, however, often difficult to determine, and the most sophisticated epidemiological methods are relatively insensitive. There are no epidemiological data for most occupational/environmental chemicals. Long-term bioassays can present major problems in design, interpretation and extrapolation. 'articular difficulties are associated with the planning of appropriate dose levels and the occurrence of certain tumours at high incidence in both control and test groups. Results from animal bioassays et priorities for concern and action but they cannot be reliably used for quantitative assessment of human risk. Evidence of potential carcinogenicity derived from short-term predictive tests, involving a wide variety of systems with diverse end-points, is increasingly important. Emphasis is placed on the teed for more in vivo procedures with a broadening of the scope of somatic cell targets.

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