Enzo Funari

Human Health Risk Assessment Related to Cyanotoxins Exposure

This review focuses on the risk assessment associated with human exposure to cyanotoxins, secondary metabolites of an ubiquitous group of photosynthetic procariota. Cyanobacteria occurr especially in eutrophic inland and coastal surface waters, where under favorable conditions they attain high densities and may form blooms and scums. Cyanotoxins can be grouped according to their biological effects into hepatotoxins, neurotoxins, cytotoxins, and toxins with irritating potential, also acting on the gastrointestinal system. The chemical and toxicological properties of the main cyanotoxins, relevant for the evaluation of possible risks for human health, are presented. Humans may be exposed to cyanotoxins via several routes, with the oral one being by far the most important, occurring by ingesting contaminated drinking water, food, some dietary supplements, or water during recreational activities. Acute and short-term toxic effects have been associated in humans with exposure to high levels of cyanotoxins in drinking and bathing waters. However, the chronic exposure to low cyanotoxin levels remains a critical issue. This article identifies the actual risky exposure scenarios, provides toxicologically derived reference values, and discusses open issues and research needs.

Nonylphenol and octylphenol in human breast milk

Human milk is the most important form of nourishment for newborn children. Its consumption is strongly recommended by health authorities also for other important advantages. Unfortunately, in the last three decades a great number of investigations have shown the occurrence of several environmental contaminants in human milk, especially those with lipophilic properties. This study investigates the presence of nonylphenol, octylphenol (OP), nonylphenol monoethoxylate (NP1EO) and two octylphenol ethoxylates (OPEOs) (namely OP1EO and OP2EO), in human breast milk of Italian women. NP was the contaminant found at the highest levels with mean concentrations of 32 ng/mL, about two orders of magnitude higher than OP (0.08 ng/mL), OP1EO (0.07 ng/mL) and OP2EO (0.16 ng/mL). In the group of study a positive correlation among fish consumption and levels of NP in the milk was observed, in accordance with the evidence that seafood represents one of the most important sources of exposure to this group of contaminants in Italy. On the basis of the concentrations found in the breast milk samples, a maximum NP daily intake of 3.94 microg/kg/day can be calculated, which is close to the Tolerable Daily Intake (TDI) of 5 microg/kg body weight (bw) proposed by the Danish Institute of Safety and Toxicology. In the cases of OP no TDI is available, but its intake is at least six orders of magnitude lower than the NOAEL of 10 mg/kg/day derived from a two generation study on rats.

Leaching indices of some major triazine metabolites

Pesticide metabolites which maintain the phytotoxic activity of the parent compounds or some kind of biological activity may represent a risk to human health if present in drinking water above certain concentrations. Using laboratory methods, the soil persistence (DT50) and mobility (Koc) of desethylatrazine, deisopropylatrazine, desethylterbuthylazine, 3-(4-hydroxycyclohexyl)-6-(methylamino)-1-methyl-1,3,5-atrazine-2,4-(1H,3H)-dione and of their parent compounds atrazine, terbutylazine, hexazinone were determined. Then, their tendency to leach (GUS indices) were calculated. Respect to their parent compounds, the examined metabolites generally have higher DT50 and lower Koc values. Consequently, they show leaching characteristics higher than their parent compounds.

Alkylphenols and their ethoxylates in seafood from the Tyrrhenian Sea

The present study reports the results of an investigation on occurrence of octylphenols (OPs), nonylphenols (NPs) and their respective ethoxylates (with 1-6 ethoxylic group) in aquatic species of commercial interest from the Tyrrhenian Sea. Samples were collected at Livorno, Fiumicino and Salerno commercial harbors, during September-October 2003. The data obtained showed that almost all of the tested compounds were found in all the samples. NP was generally detected at the highest concentrations. Among the tested species common to the three sampling sites, mullets and seabreams generally showed high values of total alkylphenols (APs) and alkylphenol ethoxylates (APEOs) (44-55 ng g(-1) and 27-525 ng g(-1) fw), yet, the maximum concentrations were found in shrimps from Fiumicino (1255 ng g(-1) fw). On the contrary, the lowest concentrations were observed in hakes and anchovies (34-36 ng g(-1) and 6-37 ng g(-1) fw). Tuna, exhibited very high concentrations of total alkylphenolic compounds (APEs) (889 ng g(-1) fw). Seafood from Fiumicino fishing area, which is under the influence of the River Tiber, showed a degree of contamination of at least one order of magnitude higher than the other two sites. On the basis of the results of this study, the corresponding daily intakes of NPs are much lower than the TDI proposed by the Danish Environmental Agency.

Contamination by Microcystis and microcystins of blue-green algae food supplements (BGAS) on the Italian market and possible risk for the exposed population.

Blue green algae supplements (BGAS) are generally proposed as health-promoting natural products for their purported beneficial effects. Spirulina spp. and Aphanizomenon flos aquae are mainly used in BGAS production. They are usually collected from the natural environment, where other potentially toxic cyanobacteria can be present, making possible BGAS contamination by cyanotoxins, with potential risk for human health. In this work we apply a combined approach, by using chemical and molecular techniques, on BGAS of 17 brands available in Italy. Samples containing Spirulina-only were free of contamination. The Aphanizomenon flos aquae-based samples were contaminated by highly variable levels of microcystins (MC-LR and MC-LA congeners), up to 5.2 μg MC-LR equivalents per gram product. The highest variability (up to 50 fold) was among batches of the same brand, although intra-batch differences were also evidenced. PCR analyses were positive only for the presence of Microcystis sp., identified as the toxin-producing species responsible for contamination. At the maximum contamination levels found, a risk for consumers can be expected following chronic or sub-chronic exposure to a reasonable daily BGAS consumption of 4 g. The need for a strict monitoring by producers and Health Authority to assure an adequate protection for consumers is underscored.

Comparison of the leaching properties of alachlor, metolachlor, triazines and some of their metabolites in an experimental field

Abstract Alachlor, metolachlor, atrazine, cyanazine, simazine and terbuthylazine were applied to plots containing a drainage system in order to determine the concentrations of parent compounds and their metabolites in soil and in leachate samples. The results indicated that all these herbicides disappeared substancially in the soil surface layer following first order kinetics. In the surface soil, the disappearance times of 50% of the concentration (DT50s) for terbuthylazine, atrazine, metolachlor, cyanazine, simazine and alachlor were 44, 35, 34, 28, 28 and 20 days, respectively. All pesticides leached to a depth of about 90 cm in the soil. After application at agricultural doses, leachate concentrations of herbicides ranged from 24 μg/l for metolachlor to 128 μg/l for cyanazine. The recoveries of the initial amount of compounds added ranged from 0.03% for metolachlor to 0.3% for simazine and its metabolite, deisopropylatrazine (DIA). Of particular interest was the high rate of formation of DIA from simazine and of desethylterbuthlazine (DET) from terbuthylazine. In the leachate, DIA occurred at concentrations much higher than simazine.

Xenobiotic-metabolizing enzyme systems in test fish. I. Comparative studies of liver microsomal monooxygenases.

All monooxygenase activities assayed in guppy (Poecilia reticulata) and red killifish (Oryzias latipes) were 7-10 times higher than those measured in trout (Salmo gairdneri), carp (Cyprinus carpio), and golden orfe (Leuciscus idus). Cytochrome P-450 was 3 times higher in the former fish than in all the other species. Zebra fish (Brachydanio rerio) 7-ethoxycoumarin O-deethylase and bluegill (Lepomis macrochirus) ethylmorphine N-demethylase (EMND) were not greatly different from those of the former group. alpha-Naphthoflavone (NF) and methyrapone (MET) exerted qualitatively different actions on benzo[a]pyrene hydroxylase of guppy, trout, and bluegill liver: both chemicals enhanced the bluegill activity and inhibited that of trout; the guppy liver enzyme was inhibited by MET and activated by NF. EMND activity was inhibited by either compound in the three species. The relevance of all these data to the European Economic Community ecotoxicity tests is discussed.

Cyanotoxins: producing organisms, occurrence, toxicity, mechanism of action and human health toxicological risk evaluation

Abstract Cyanobacteria were present on the earth 3.5 billion years ago; since then they have colonized almost all terrestrial and aquatic ecosystems. They produce a high number of bioactive molecules, among which some are cyanotoxins. Cyanobacterial growth at high densities, forming blooms, is increasing in extension and frequency, following anthropogenic activities and climate changes, giving rise to some concern for human health and animal life exposed to cyanotoxins. Numerous cases of lethal poisonings have been associated with cyanotoxins ingestion in wild animal and livestock. In humans few episodes of lethal or severe human poisonings have been recorded after acute or short-term exposure, but the repeated/chronic exposure to low cyanotoxin levels remains a critical issue. The properties of the most frequently detected cyanotoxins (namely, microcystins, nodularins, cylindrospermopsin and neurotoxins) are here critically reviewed, describing for each toxin the available information on producing organisms, biosynthesis/genetic and occurrence, with a focus on the toxicological profile (including kinetics, acute systemic toxicity, mechanism and mode of action, local effects, repeated toxicity, genotoxicity, carcinogenicity, reproductive toxicity; human health effects and epidemiological studies; animal poisoning) with the derivation of health-based values and considerations on the risks for human health.

Human glutathione transferases catalyzing the conjugation of the hepatoxin microcystin-LR.

Many cyanobacterial species are able to produce cyanotoxins as secondary metabolites. Among them, microcystins (MC) are a group of around 80 congeners of toxic cyclic heptapeptides. MC-LR is the most studied MC congener, in view of its high acute hepatotoxicity and tumor promoting activity. Humans may be exposed to cyanotoxins through several routes, the oral one being the most important. The accepted pathway for MC-LR detoxication and excretion in the urine is GSH conjugation. The GSH adduct (GS-MCLR) formation has been shown to occur spontaneously and enzymatically, catalyzed by glutathione transferases (GSTs). The enzymatic reaction has been reported but not characterized both in vitro and in vivo in animal and plant species. No data are available on humans. In the present work, the MC-LR conjugation with GSH catalyzed by five recombinant human GSTs (A1-1, A3-3, M1-1, P1-1, and T1-1) has been characterized for the first time. All GSTs are able to catalyze the reaction; kinetic parameters K(m), k(cat), and their relative specific activities to form GS-MCLR were derived (T1-1 > A1-1 > M1-1 > A3-3 ≫ P1-1). In the range of MC tested concentrations used (0.25-50 μM) GSTT1-1 and A1-1 showed a typical saturation curve with similar affinity for MC-LR (≈80 μM; k(cat) values 0.18 and 0.10 min(-1), respectively), A3-3 and M1-1 were linear, whereas GSTP1-1 showed a temperature-dependent sigmoidal allosteric curve with a k(cat) = 0.11 min(-1). The enzymes mainly expressed in the liver and gastrointestinal tract, GSTA1-1, T1-1, and M1-1, seemed to be mainly involved in the MC-LR detoxification after oral exposure, whereas P1-1 kinetics and location in the skin suggest a role related to dermal exposure. Considering the high frequency of some GST polymorphism, especially M1 and T1 gene deletion, with complete loss in activity, this information could be the first step to identify groups of individual at higher risk associated with MC exposure.

Impact of climate change on waterborne diseases

Change in climate and water cycle will challenge water availability but it will also increase the exposure to unsafe water. Floods, droughts, heavy storms, changes in rain pattern, increase of temperature and sea level, they all show an increasing trend worldwide and will affect biological, physical and chemical components of water through different paths thus enhancing the risk of waterborne diseases. This paper is intended, through reviewing the available literature, to highlight environmental changes and critical situations caused by floods, drought and warmer temperature that will lead to an increase of exposure to water related pathogens, chemical hazards and cyanotoxins. The final aim is provide knowledge-based elements for more focused adaptation measures.