Occurrence and toxicological evaluation of cyanobacterial toxins in Alberta lakes and farm dugouts

Kotak, Brian G.; Kenefick, S. L.; Fritz, David L.; Rousseaux, Colin G.; Prepas, E. E.; Hrudey, Steve E.

doi:10.1016/0043-1354(93)90050-r

Cited by 140 publications

(63 citation statements)

References 24 publications

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“…However, there was a significant correlation between Microcystis biomass and intracellular MCs concentration in the water column, suggesting that seasonal and spatial variations of intracellular microcystins in the water column were the result of the changes of Microcystis biomass. Kotak et al (1993) showed that microcystin-LR concentration in phytoplankton can be highly dynamic, reflecting, at least partially, changes in the abundance or biomass of M. aeruginosa within a lake, temporally within and between years, and even over 24 h. Zurawell et al (1999) reported that concentration of MC-LR in the phytoplankton varied within each lake probably in response to fluctuations in the relative and absolute abundance of Microcystis spp.…”

Section: Discussionmentioning

confidence: 99%

Spatial and temporal variations of microcystins in hepatopancreas of a freshwater snail from Lake Taihu

Zhang

Xie

Liu

et al. 2009

Ecotoxicology and Environmental Safety

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Section: Discussionmentioning

confidence: 99%

Spatial and temporal variations of microcystins in hepatopancreas of a freshwater snail from Lake Taihu

Zhang

Xie

Liu

et al. 2009

Ecotoxicology and Environmental Safety

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“…In freshwater, blooms of cyanobacteria (blue-green algae) are a prominent symptom of eutrophication (Kotak et al 1993, McComb and Davis 1993, Smith 1998. These blooms contribute to a wide range of water-related problems including summer fish kills, foul odors, unpalatability of drinking water, and formation of trihalomethane during water chlorination in treatment plants (Palmstrom et al 1988, Kotak et al 1994).…”

Section: Why Is Nonpoint P and N Pollution A Concern?mentioning

confidence: 99%

Nonpoint Pollution of Surface Waters with Phosphorus and Nitrogen

Carpenter¹,

Caraco²,

Correll³

et al. 1998

Ecological Applications

1,957

2,399

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Abstract. Agriculture and urban activities are major sources of phosphorus and nitrogen to aquatic ecosystems. Atmospheric deposition further contributes as a source of N. These nonpoint inputs of nutrients are difficult to measure and regulate because they derive from activities dispersed over wide areas of land and are variable in time due to effects of weather. In aquatic ecosystems, these nutrients cause diverse problems such as toxic algal blooms, loss of oxygen, fish kills, loss of biodiversity (including species important for commerce and recreation), loss of aquatic plant beds and coral reefs, and other problems. Nutrient enrichment seriously degrades aquatic ecosystems and impairs the use of water for drinking, industry, agriculture, recreation, and other purposes.Based on our review of the scientific literature, we are certain that (1) eutrophication is a widespread problem in rivers, lakes, estuaries, and coastal oceans, caused by overenrichment with P and N; (2) nonpoint pollution, a major source of P and N to surface waters of the United States, results primarily from agriculture and urban activity, including industry; (3) inputs of P and N to agriculture in the form of fertilizers exceed outputs in produce in the United States and many other nations; (4) nutrient flows to aquatic ecosystems are directly related to animal stocking densities, and under high livestock densities, manure production exceeds the needs of crops to which the manure is applied; (5) excess fertilization and manure production cause a P surplus to accumulate in soil, some of which is transported to aquatic ecosystems; and (6) excess fertilization and manure production on agricultural lands create surplus N, which is mobile in many soils and often leaches to downstream aquatic ecosystems, and which can also volatilize to the atmosphere, redepositing elsewhere and eventually reaching aquatic ecosystems.If current practices continue, nonpoint pollution of surface waters is virtually certain to increase in the future. Such an outcome is not inevitable, however, because a number of technologies, land use practices, and conservation measures are capable of decreasing the flow of nonpoint P and N into surface waters.From our review of the available scientific information, we are confident that: (1) nonpoint pollution of surface waters with P and N could be reduced by reducing surplus nutrient flows in agricultural systems and processes, reducing agricultural and urban runoff by diverse methods, and reducing N emissions from fossil fuel burning; and (2) eutrophication can be reversed by decreasing input rates of P and N to aquatic ecosystems, but rates of recovery are highly variable among water bodies. Often, the eutrophic state is persistent, and recovery is slow.

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“…The harmful concentrations for an acute intoxication with the most abundant cyanobacterial toxin in freshwater can be calculated as follows (Fromme et al, 2000): On the basis of mouse studies (Hooser et al, 1989;Kotak et al, 1993;Fawell et al, 1994;Yoshida et al, 1997), it can be assumed that a single intake of 12.5, 50 or 150Ag MC-LR equiv. should not have adverse effects in toddlers (5 kg), young children (20 kg) and adults (60 kg), respectively.…”

Section: Acute Intoxication Scenariomentioning

confidence: 99%

“…High and therefore visible densities of cyanobacteria should prevent most people from swimming in such (2) 100 Ag/l 125 ml 500 ml 1500 ml 1000 Ag/l 12.5 ml 50 ml 150 ml Drinking water (3) 1.0 Ag/l 12,500 ml 50,000 ml 150,000 ml 100 Ag/l 125 ml 500 ml 1500 ml BGAS (4) 1.0 Ag/g 12.5 g 50 g 150 g 10 Ag/g 1.25 g 5 g 15 g Therefore, the lowest dose with no hepatotoxic effects after i.p. injection was chosen (25 Ag/kg bw, (Kotak et al, 1993), multiplied by 10 for i.p. to p.o.…”

Section: Subchronic To Chronic Intoxication Scenariomentioning

confidence: 99%

Guidance values for microcystins in water and cyanobacterial supplement products (blue-green algal supplements): a reasonable or misguided approach?

Dietrich

Hoeger

2005

Toxicology and Applied Pharmacology

325

185

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This article reviews current scientific knowledge on the toxicity and carcinogenicity of microcystins and compares this to the guidance values proposed for microcystins in water by the World Health Organization, and for blue-green algal food supplements by the Oregon State Department of Health. The basis of the risk assessment underlying these guidance values is viewed as being critical due to overt deficiencies in the data used for its generation: (i) use of one microcystin congener only (microcystin-LR), while the other presently known nearly 80 congeners are largely disregarded, (ii) new knowledge regarding potential neuro and renal toxicity of microcystins in humans and (iii) the inadequacies of assessing realistic microcystin exposures in humans and especially in children via blue-green algal food supplements. In reiterating the state-of-the-art toxicology database on microcystins and in the light of new data on the high degree of toxin contamination of algal food supplements, this review clearly demonstrates the need for improved kinetic data of microcystins in humans and for discussion concerning uncertainty factors, which may result in a lowering of the present guidance values and an increased routine control of water bodies and food supplements for toxin contamination. Similar to the approach taken previously by authorities for dioxin or PCB risk assessment, the use of a toxin equivalent approach to the risk assessment of microcystins is proposed. D

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Occurrence and toxicological evaluation of cyanobacterial toxins in Alberta lakes and farm dugouts

Cited by 140 publications

References 24 publications

Spatial and temporal variations of microcystins in hepatopancreas of a freshwater snail from Lake Taihu

Spatial and temporal variations of microcystins in hepatopancreas of a freshwater snail from Lake Taihu

Nonpoint Pollution of Surface Waters with Phosphorus and Nitrogen

Guidance values for microcystins in water and cyanobacterial supplement products (blue-green algal supplements): a reasonable or misguided approach?

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