Cylyndrospermospis (CYN) Algae - Essay Example

? Cylyndrospermospis Area of study Cyanobacteria (or blue-green algae) are very abundant in fresh and saline waters worldwide that produce toxin called Cylindrospermopsin. When these toxins are present in aquatic hinterlands, seafood harvested from there may present health hazards to consumers. Such toxicity hazards from seafood are recognized internationally when they are from marine algae (diatoms and dinoflagellates), but nowadays few risk assessments for Cylindrospermopsin in seafood have been conducted. This paper estimates the risk from Cylindrospermopsin contaminated seafood, and provides strategies for safe human consumption. The paper analyses the risk of Cylindrospermopsin toxicity in human beings posed by consumption of seafood which are highly regarded s the toxin agents. The assessment covers the risk of exposure through seafood consumption by residents of Victoria, Australia, around the Gippsland Lakes, neglecting other kinds of exposure since the place where the field of study is other factors are either do not exist or are neglable. These other risk factors include: exposure due to recreational activities, which is highly advocated against in the area; and exposure through drinking water, which is ruled out since the water drunk the residents is not sourced at the Cyanobacteria infested Gippsland Lakes. Introduction Cylindrospermopsin is a toxin that occurs naturally, and is produced by specific strains of Cylindrospermopsis raciborskii among at least 4 other freshwater cyanobacterial species, counting Umezakia natans, Anabaena bergii, Raphidiopsis curvata and Aphanizomenon ovalisporum (Aldrich, 2012, p. 3). Cylindrospermopsin chemical structure was not clarified until 1992. It comprises of a tri-cyclic guanidine moiety combined with hydroxyl-methyl-uracil. Its molecular formula is C15H21N5O7S and molecular weight is 415.43. It is zwitterionic (a di-polar ion with localized negative and positive charges). Deoxycylindro-spermopsin, a cylindrospermopsin analog in which the hydroxyl group in the uracil bridge has been removed, isolated from R. curvata and C. raciborskii (Aldrich, 2012, p. 3) . 7-epicylindrospermopsin is another structural variation of cylindrospermopsin which was isolated from A. ovalisporum. The Gippsland Lakes is a coastal lagoons system located at southeast of Victoria in Australia, approximately 200 kilometers east Melbourne and are key for commercial, tourist and recreational activities. The Lakes act as a source of commercial seafood, including fish, crustaceans and shellfish, as well as providing general recreational fishing. Considerable modifications have occurred on the Lakes catchments since European settlement with fisheries and agricultural development, including the establishment of a permanently open Bass Straight entrance in 1889. This environment, once freshwater lake, is currently a more saline and high nutrient expanse, and cyanobacterial (the blue-green algal) blooms are now becoming a normal occurrence. Ever since 1985, there have existed 7 non-cyanobacterial blooms noted in the Lakes (commonly dinoflagellates or diatoms), and 12 cyanobacterial blooms (Kaarina Sivonen, 1999, p. 4). Nodularia spumigenna is the most common cyanobacterium to bloom, with periodic Microcystis aeruginosa and Anabaena circinalis blooms (Anon., n.d., p. 169) So as to provide guidance and to delineate acceptable levels of Cylindrospermopsin in seafood in Victoria, the Victorian Health Department convened a scientific advisory professional to perform a risk assessment regarding recreational and commercial seafood safety in the Victoria Gippsland Lakes (Kankaanpaa, 2005, p. 3). The seafood of concern was fish, mussels and prawns from these lakes. Cylindrospermopsin was among the toxins detected in the risk assessment, others being saxitoxins, microcystins, nodularin - all of which are found in Australian aquatic surroundings and are distributed global (Moreira, et al., 2012, p. 3). Cyanobacterial blooms largely depend on water temperature and nutrient availability, and the predominant species impacted by salinity. Warmer waters over summer accelerate the organisms’ growth. Cyanobacterial blooms are a big public health concern since the Cylindrospermopsin toxins that some cyanobacteria species produce can have severe effects on consumers, whether there is through drinking water and seafood or recreational exposure. All 3 common bloom-forming cyanobacteria within the Gippsland lakes remain toxic to the environment. Nodularia spumigena, which is ample in the Lakes, was identified as the first cyanobacteria to be in scientific literature as the reason of livestock poisoning in 1877 (Craig, 2012, p. 9). Cylindrospermopsin toxin has been shown to bio-accumulate in aquatic organisms like fish, prawns and shellfish, and have previously caused restrictions on the harvesting of the organisms from the Lakes. Methods (i) The Risk Assessment Methodology Human standard health risk assessment methodology was employed, which includes the following stages: - Hazard identification—qualitative calculation of the likeliness of an agent or chemical to cause adversative effects in human beings. - Dose-response assessment—analysis of the quantitative correlation between the hazard at diverse exposure levels and the frequency of adverse effects in human beings. - Exposure assessment—determination of routes, frequency and time of the exposure, and the nature of the exposed populations. - Risk characterization—integration of hazard existence, dose-response and exposure analysis information. Hazard Identification Carrying out hazard identification and the dose-response assessment of Cylindrospermopsin in seafood, most of related studies identified had been assumed on marine dinoflagellate origin saxitoxins, with few reported cases on human Cylindrospermopsin toxicity related with seafood consumption. Additionally, none of reported cases detailed the severe effects in human being as a dose function However, human toxicity from Cylindrospermopsin toxin contamination on dialysis fluid, drinking water plus recreational water ingesting has been demonstrated (Vasconcelos, 1999, p. 251). Dose-Response Assessment Having no direct information concerning the human health Cylindrospermopsin risks in seafood as a degree of exposure function (dose-response), it is essential extrapolating information from some animal toxicity studies (Aldrich, 2012, p. 3). There are various types of animal studies that are used in identifying hazards and assessing the dose-response. These studies include acute, chronic, sub-chronic, developmental and reproductive toxicity, and genotoxicity (Kankaanpaa, 2005, p. 254). As only oral exposure remains relevant when considering toxicity exposure from seafood, the published literature’s animal studies that were conducted in line with the OECD Guideline for Testing Chemicals (1998) for the sub-chronic oral toxicity got assessed. Experimental figures from 2 species, a rodent and a non-rodent, were employed. On determining the safe doses of possibly toxic materials in the food, toxicological data is used in calculating Tolerable Daily Intake (TDI). TID is an estimate of intakes of substances which are without considerable health risk to their consumers over their lifetime. Conversely, as the Cylindrospermopsin is acutely toxic and consumers can eat large portion sizes in single occasions, it is also suitable to consider creating acute reference dose (ARfD) (Kaarina Sivonen, 1999, p. 4). ARfD is an estimated “amount of a substance in food / drinking water, usually expressed on body weight that can be ingested to the body in a period of I day or less without considerable health risks to its consumer on the terms of all known actualities at the period of the evaluation”. The ARfD is used in estimating the dietary risk for the consumers who eat large quantities of seafood on a one meal or over one day, where else the TDI is used in estimating the dietary risk for the consumers who eat the average quantity of seafood over their lifetime. Both ARfD and TDI are calculated from an experimental data of intake of the substance that has no detectable adversative health effects, normally named No Observed Adverse Effects Levels (NOAEL). Ambiguity factors are applied in the NOAEL to allow variations in individual sensitivity, the extrapolation between animal and human studies and to account the data uncertainties. The standard factors areas follows; 10 for intra-species (within human) variability as well as 10 for inter-species (rodents compared to humans) variability, and an additional (3rd) variable factor for limitations / precincts in the data. Limitations / precincts in the data that that extra factor may account for comprise: the use of a single species or sex of animal; possibility of carcinogenicity or mutagenicity; reproductive or toxicity teratogenicity. In the origin of all health standard values for Cylindrospermopsin in seafood (refer the chapter below) this extra factor was allocated a value of 2 (Kaarina Sivonen, 1999, p. 1). In every toxin the limitations / precincts in the data that demanded this value of two varied. It should be understood, though, that for none of Cylindrospermopsin toxins did this value purpose to allow for the point the toxicity trials remained sub-chronic rather than for lifetime. For the toxins this was not considered as a limitation of data because the irregularity and seasonality of toxic cyanobacterial blooms imply that human exposure to Cylindrospermopsin will range between acute and sub-chronic. The total uncertainty factor for the toxin used in health guideline values derivation became 200 (10 ? 10 ? 2) Exposure Assessment To convert ARfD or TDI to a seafood health guideline value it is essential to carry out an exposure assessment to integrate information with the consumers’ bodyweight; the amount of seafood consumed; as well as the probability that the consumer may get exposed to Cylindrospermopsin via other sources (for instance, through drinking water or recreational undertakings). Average body weights for particular age groups (which is 2–16 years and 17 years or above) were sourced from recent nutritional surveys (Chorus, 1999, p. 77). For acute dietary risks assessment aims and to protect consumers against high levels of seafood consumption, data of high-level consumption of mollusks, prawns and fin fish (97.5th percentile intake) extracted from the National Nutrition Survey 1995 (NNS), for 17 years old and above consumers (Table 1). As for children aged between 2 and 16 years, a more recent Australian National Children Nutrition and Physical Activity (2007) Survey was used (Table1). It is not possible to begin generic health guideline values that would be pertinent to other areas of the world since seafood consumption patterns vary considerably. However, if the average bodyweights of consumers and high-level intake data are available, it is therefore possible to use the delineated procedure to derive appropriate health guideline values in other countries where seafood intake patterns differ substantially from New Zealand and Australia Table 1: 97.5th percentile High level seafood consumption Age group (yrs) Commodity Consumer intakes g/kg BW 5/day g/day Survey ?17 Fish (saline and freshwater) 5.2 378 2005 Prawns 5.2 375 Mussels 2.6 176 2 – 16 yrs Fish (saline and freshwater 8.8 329 2007 Prawns 6.2 235 Mollusks 3.9 Notes: Australia National Nutrition Survey (NNS) 1995, surveying 13858 people aged Two years and above. This survey used a 24-hour recall for each respondents and a 2nd 24-hour recall for about 10% of respondents; 2007 Australian National Children Nutrition and Physical Activity 2007 Survey (NCS), surveying 4487 people between 2 and 16 years old. The survey did two 24-hrs recalls for all respondents. To estimate the acute dietary exposures only one day 24-hour recall was used; Diadromous and freshwater fish intake excluding all marine fish; The food consumption data drawn in the table entails the amount consumed as an ingredient or component in mixed foods and those consumed alone. In DIAMOND, FSANZ dietary exposure assessment, a computer program, every mixed foods consist of a recipe. These recipes were used in categorizing mixed foods to their raw commodity constituents. For instance fish in a fish casserole should be included in fish consumption data; Bodyweights: 38kg 2–16 years; 73kg > 17 years; Consumption amounts for mollusks were used where there was inadequate mussels' consumers alone to derive a usable 97.5th percentile consumption value (Craig, 2012, p. 7). Only 11 consumers of mussels within the 2 to 16 year age set dataset. “Mollusks” includes mussels, octopus, oysters, squid and scallops. Allocation Factor In the setting of this report is defined as the quantity of toxin exposure gained by consumption of seafood. The one likely route of exposure to Cylindrospermopsin toxin would be through consumption of seafood. The local drinking water is not obtained from Gippsland Lakes, plus recreational usage of the lakes is intensely advised against the moment a noteworthy cyanobacterial bloom befalls, as per the Managing Risks in Recreational Waters Guidelines (Kaarina Sivonen, 1999, p. 2). An allocation factor of 1 (or 100% of Cylindrospermopsin exposure gained as a result of consumption of seafood) was for that reason deemed appropriate. Risk Characterization It is proper to contemplate the acute dietary risks postured by the presence of Cylindrospermopsin toxins in seafood since they remain acutely toxic and consumers can eat large portions on incidents. Therefore, the forming of maximum levels (abbr. MLs) for seafood should preferably be based on acute dietary risk characterization, which would be appropriately protective of excessive chronic disclosures as the target organs are the same following either one or repeated dietary exposures (Rasco*, 2010, p. 260). There is a scarcity of data on the verges of acute oral toxicity of Cylindrospermopsin toxins and therefore limited the potential to create an ARfD for cylindrospermopsin. On this fact, a conservative methodology has been taken when the high-level intake (97.5th percentile consumption) of fish, prawns, mollusks or mussels have been compared with TDI. It is two population groups that have been evaluated; 2–16 year olds and 17 years and above. By integrating hazard identification, exposure assessment information and dose-response, health guideline values of cylindrospermopsin in seafood can be got from. The stages are as below: Step I: Determining the TDI (?g/kg bwgt/day): TDI (?g/kg bwgt/day) = NOAEL ? Uncertainty Factors Step II: Determining the acceptable boundary of cylindrospermopsin consumption per person in a day (?g/day): Acceptable limit (?g/day) = ARfD (or TDI) ? average bodyweight (kg) ? the allocation factor Step III: Defining the high seafood level intake per consumer in a day (kg/day). Step IV: Deriving health guidelines level of cylindrospermopsin in seafood: Guideline value (?g/Kgs) = Acceptable limit (?g/day) ? intake of seafood in a day (kg/day) The health guideline values should be derived for cylindrospermopsin toxin separately for each seafood (mollusks, prawns and mussels or fish) using different average intake values. Health Guidelines Values derivation Cylindrospermopsin occurs in fresh and salty waters globally, due to the existence of the cyanobacterial Aphanizomenon, Anabaena, Raphidiopis, Lyngbya genera Cylindrospermopsis, and Umezakia. Cylindrospermopsin bioaccumulation studies on gastropod snails, crustaceans, tadpoles and fish proved that the toxin is concentrated in the tissues free solution and the from toxic Cylindrospermopsis cells (Everson, et al., 2008, p. 25). Highest accumulation was noticed in mussels with the whole-body concentration of about 3mg/kg dry weight, and the maximum tissue concentration seen in haemolymph. Cylindrospermopsin toxin is seen in muscle tissues as well and viscera, increasing the likelihood of consumption of these foods. Human poisoning from Cylindrospermopsin has been previously recorded before. In Palm Island 1979, for instance, 150 people received hospital cure for an unusual hepatoenteritis due to drinking water from a local reservoir that was treated using copper to remove existing Cylindrospermopsis algal bloom (Aldrich, 2012, p. 6). The absence of Cylindrospermopsis exposure information, however, makes the case unusable for the aim of deriving the TDI. There have been however, several published explanations of oral toxicity of cylindrospermopsin within animals, with most studies using single doses. Repeat oral dosing after 2wks interval indicated unexpectedly greater toxicity, indicating residual damage in animals from the initial dose. A study by Falconer and Humpage, following the protocols set by the OECD of sub-chronic oral toxicity assessment on rodents, exposed male Albino mice to cylindrospermopsin toxin through drinking water and gavage (dosing by mouth) (Chorus, 1999, p. 76). In the first trial, cylindrospermopsin-containing removed from cultured Cylindrospermopsis raciborskii, was supplied on drinking water for 10wks. The cylindrospermopsin dose ranged from 0 - 657 ?g/kg/day at four levels. The animals were inspected clinically during the test and showed no ill impacts other than small dose-related s in body weight as compared to the controls after 10wks. Kidney and liver weights were significantly bigger with increasing dose. Various biochemical indicators of functioning of liver exhibited dose-related changes. For example, serum total albumin and bilirubin increased, whereas serum bile acids reduced. Liver enzyme changes in serum showed a different form to those found with hepatitis acute or liver poisoning, as only a small upsurge in serum alanine aminotransferase with a greater upsurge in alkaline phosphatase were detected. There was also a drop in aspartate aminotransferase. The utmost considerable change observed was in urine protein/creatinine concentration, whereby the protein decreased sharply with the dose. This was construed as replicating decreased protein synthesis in kidney through reticence by the toxin. Histo-pathological examination of all internal body organs showed variations only in the kidney and liver. Dose-related renal proximal tubule necrosis and hepatocyte damage were also observed. When it was ostensible from these outcomes of low oral doses were needed to find the NOAEL, Falconer and Humpage carried out a 2nd trial in which mice got dosed orally over 11wks with zero, 30, 60, 120 to 240 ?g/kg/day of refined cylindrospermopsin toxin (Sukenik, et al., 2006, p. 579). The same tendencies in serum parameters were displayed, but with no statistically substantial changes. Organ weights displayed most sensitivity to the lower doses with considerable increases in body weights, while a portion of body weight adrenal glands, in, liver, testis and kidney. Minor histopathological damage was revealed in the liver at two upper dose levels, as well as in kidney proximal tubules on the highest dose. Urine creatinine / protein decreased progressively with dose, getting significance at around 120 ?g/kg/day of the oral cylindrospermopsin (Craig, 2012, p. 3). At very low doses levels of cylindrospermopsin compensatory changes happen in metabolism to reinstate homeostasis. The increases in body organ weight can be anticipated to compensate for declines in function as realized in the kidneys and liver, and compensation for pressures resultant from the toxin, for instance in the adrenal glands. Therefore it becomes subjective to choose where the NOAEL occurs, depending on which impact is considered adversative. From the urine protein information it is apparent that NOAEL is under120 ?g/kg/day. However, statistically substantial change in kidney weight ensued at 60 ?g/kg/day. Therefore, to adopt the conservative perspective that the much sensitive response have to be considered as an indicator of adversative effect, the 30 ?g/kg/day dose was acknowledged as the NOAEL from the trials (Ross, 2002, p. 58). Recent studies have validated this value and exposed that both females and males are affected at a similar level. Therefore, using 30 ?g/kg/day as NOAEL, the cylindrospermopsin TDI can be calculated as follows:- TDI(?g/kg/day) = 30 ? Uncertainty factors The uncertainty factor is 10 for intra-species variability, 10 for inter-species variability and an extra factor of 2 owing that there is new evidence that cylindrospermopsin has reproductive and teratogenicity effects, and there is initial evidence that it could be carcinogenic. Under these circumstances a rational additional improbability factor of 2 is appropriate. Step I: TDI = 30 ? 200 = 0.15?g/kg/day Step II: Acceptable limit in a day = 0.15?g/kgs/day ? bodyweight (kgs) ? 1.0 (allocation factor). Table2. Acceptable cylindrospermopsin daily limits with bodyweight and age. Age (yrs) Average bodyweight (kgs) Acceptable daily limits (?g/day) ?17 74 11 2–16 39 5.7 Step III: Obtaining a high-level consumption data on 17 years old and above consumers and 2 to 16 years old (see Table1.) Step IV: Derive health guideline level (?g/kgs) for cylindrospermopsin in entire seafood sample see (Table3). Acceptable limit (?g/day) ? consumption (kgs/day) (i.e Step 2 ? Step 3). Table3: Acceptable cylindrospermopsin daily limits for with bodyweight and age Health Guideline Value (?g/kgs of whole organism trials) Age group (yrs) Fish Prawns Mussels/Mollusks ?17 29 29 63 2–16 17 24 38 Preliminary in vitro evidence proposes that deoxy-cylindrospermopsin has similar potency to cylindrospermopsin, and so this analogue have to be included in toxicity assessments and monitoring programs. Distribution and detection Cylindrospermopsin toxin has been recorded from various Nostocalean species and lately from one Oscillatoriale. The main species for Cylindrospermopsin production is Cylindrospermopsis raciborskii, which can occupy a varied range of environments counting intensively-flushed lotic bodies as well as newly built reservoirs. The dispersal of C. raciborskii was studied by Padisak, who catalogued blooms befalling in tropical and sub-tropical countries as well as those growing in temperate climes (Remedios Guzman-Guillen, 2012, p. 2234). However, whether Cylindrospermopsin co-occurred at majority of these regions was not validated. Fresh reports have also been released of other Cylindrospermopsin, deoxy-Cylindrospermopsin and epi-Cylindrospermopsin producers including Raphidiopsis, Aphanizomenon, Lyngbya, Umezakia and Anabaena; Aph. gracile has lately been flagged as still another Cylindrospermopsin producer. The toxin is therefore now reported from Asia, central, northern and southern Europe, North and South America, Africa, and majorly in Australia/New Zealand–all continents except the Antarctic (Moreira, et al., 2012, p. 2). The toxin is now oncoming an almost cosmopolitan dispersal pattern and Cylindrospermopsin producers are recorded from locales including lakes, reservoirs, rivers, dams and ponds. Nevertheless, it is predictable that many locations where Cylindrospermopsin is present will remain unnoticed, as some producer organisms seldom form visible surface or blooms, even during intense blooms The global distribution of algae blooms known to contain Cylindrospermopsin or a Cylindrospermopsin -analog. Note that: ‘non-toxic’ designates bloom from which significant toxicity has not being studied or not confirmed; According to Kling, developments in food and water quality monitoring are main contributors to the number of new sites from which C. raciborskii is recorded (Moreira, et al., 2012, p. 5). However, it is also probable that the organism is mounting into suitable habitats made freshly available by a amalgamation of species’ own adaptability, climate change, and increased eutrophication. Padisak noted that the capability of C. raciborskii of travelling long river courses, surviving swampy or a little saline environments, and producing resistant akinetes has added to expansion of the species on a universal scale. Global climate change is also been considered as a activator for the progressively widespread distribution, duration and frequency of C. raciborskii blooms, particularly into the subtropical and temperate areas. Here, the impacts of climate change are more insidious than merely an increased surface temperatures upper limit For instance; winter warming combined with increased evapo-transporation has led to decreased water volumes in Mediterranean, hence encouraging a stable water buttress conducive to the C. raciborskii blooms. Moreover, changes in, and amplification of land usage activities within various catchment regions worldwide is also connected with an increased occurrence of blue-green dominion. In future, it is expected that the combined impact of these influences will imply an ever-increasing habitat from which Cylindrospermopsin will be recorded (Moreira, et al., 2012, p. 6). Studies on mechanism of Cylindrospermopsin toxicity The effects of Cylindrospermopsin have been studied in animal species, or their target risk organs and cells. Much recent studies of Cylindrospermopsin have expanded toxicity replicas to show impacts in invertebrates, zooplankton, phytoplankton, protozoans and bacteria. There is considerable erraticism amongst the toxicity of Cylindrospermopsin between diverse animal models and different people of the same species. Plants studies have only been limited to only 3 reports on tobacco, Hydrilla duckweed and species (Moreira, et al., 2012, p. 3). Generally, however, Cylindrospermopsin exposure is characterized by late toxicity involving multiple body organ systems, principally the kidney and liver. Toxicity is mediated by failure in protein synthesis, and genotoxicity by DNA fragmentations (Kankaanpaa, 2005, p. 5). It is apparent that the metabolic instigation of Cylindrospermopsin is linked with greater toxicity, though the precise path for this remains indistinct. Interestingly, it is this property of CYN (where toxin metabolism must befall before full toxicity is conveyed) that also offers some defense to exposed species. For instance, plants and animals without a developed toxin metabolism system (hepatopancreas liver) typically feature reduced toxicity, same as the early developmental phases of mammalian species (Everson, et al., 2008, p. 580). Notably, to date, Cylindrospermopsin remains unique amongst all the algal toxins in initiating toxicity in utero, being connected with premature births, decreased weight and increased mortality among mice puppies. It has also been established that Cylindrospermopsin has some latent for endocrine disruption: a study showed the toxin can alter the estrogen - progesterone ratio in women, though this result must be understood with caution given the erraticism amongst the tested individuals. Where to Next? As the global climate change and other burdens increases the range of cylindrospermopsin producers into subtropical and moderate climes, more plants and animals will become vulnerable to cylindrospermopsin biomagnification and bioaccumulation. In turn, this will result to accompanying ecosystem and human health consequences. Unfortunately, toxicological research is frequently prioritized based only on its aptitude to enlighten human health risk assessments. Wherever bioaccumulation studies have been done, this is done mainly from the perception of food web toxin transference, hence the prospective for human consumption. The near-term research urgencies for cylindrospermopsin identified by various researchers in that volume involved studies of genotoxicity, toxicokinetics and carcinogenicity, as well as developmental effects reproductive, and immunologic, and better descriptions of cylindrospermopsin activation, distribution and toxin binding. With the exclusion of trials examining binding and distribution, few of these a directly relevant to understanding cylindrospermopsin’s bioaccumulative potential. Studies to explain the mechanism of cylindrospermopsin toxicity, in both in vivo and in vitro models, will be beneficial in linking with bioaccumulation effort. Researches on sequential and simultaneous exposure to carcinogenic toxins, and to toxin combinations, should be done to discover the possibility for additive, antagonistic or synergistic effects. This is vitally significant since single cylindrospermopsins virtually never exist in nature. Serious human health effects are posed by the blooms which contain cylindrospermopsin. The distribution of cylindrospermopsin producers is growing; circumstances predisposing animals to bioaccumulation are numerous than ever before. Up to now, the research focus for cylindrospermopsin has been squarely touched human health risks, with very few studies on environmental impacts, and even fewer still on bioaccumulation. The data showing the evidence of cylindrospermopsin accumulation has been present since 2000, but compared with toxicological researches, few studies have been done on bioaccumulation generally (Sukenik, et al., 2006, p. 3336). This is quite unfortunate given that cylindrospermopsin is growing in prominence and bioaccumulation has main implications for ecological and human health risks. Without more studies, current risk assessments almost certainly take too lightly the overall risks of these toxin-containing blooms. Conclusion Despite the developments in toxin detection in drinking and recreational water, the difficult of detecting the toxins that are bound into foods tissues remains tricky. Also, in terms of scientific studies, retrieval and purification of cylindrospermopsins from spent culture media is the most effective way of obtaining quality toxin to work on with. Commercial standards for cylindrospermopsin remain slowly becoming available, like ELISA-based detection kits are. However, few laboratories are purveyors, so the further development in both these resources remains to be of high primacy. Radio-labeling of cylindrospermopsin would enable studies on if the toxin can permeate every cell membrane. However, only a single report has been produced of such study using 14C-labelling on mice. The occurrence of nuisance blooms or growths of cyanobacteria in water bodies and reservoirs that act as a source of food poses a potential risk on the quality of water since many species are able to produce secondary metabolites that can be toxic or impart unfriendly odors and taste. Cylindrospermopsin, a strong cytotoxic alkaloid produced by various has gained increasing responsiveness following its insinuation as the causative agent of mass human intoxication and numerous livestock mortalities. In many circumstances the toxicity is sub-lethal to these aquatic organisms, which allows them to survive long enough and accumulate toxins hence transferring them along a food chain. It is likely that Cylindrospermopsin concentration in seafood can reach to a level at which human intake must be discouraged. On the exception of the international adoption of saxitoxins guideline levels in seafood (for instance based on Food Standards in Australia New Zealand (the FSANZ) Food Standard), there are no domestic guidelines that direct on safe levels of Cylindrospermopsin toxins in seafood. Bibliography Aldrich, S., 2012. Cyanobacterial Toxins. Sigma Aldrich, 3(Cyanobacterial Toxins), p. 5. Anon., 2005. Estimating the nodularin content of cyanobacterea blooms from abundance of Nodularial spumigena and its characteristic pigment— case study from the Baltic e ntrance area. Harmful Algae, 4(2), p. 167–178. Anon., 2007. Cyanobacteria and prawn farming in northern New South Wales, Australia—a case study on cyanobacteria diversity and hepatotoxin bioaccumulation. Toxicology and Applied Pharmacology. Chorus, I., 1999. Toxic Cyanobacteria in Water: Guides to their public health impacts,. World Heath Organization, Volume 8, p. 70-77. Craig, J., 2012. 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