Chronic Dietary Exposure Research Articles

Chronic dietary exposure to pesticide residues in the United States

Discussions as to the extent of pesticide residue contamination in the food supply often rely on results of government residue monitoring programs focusing primarily upon the percentages of samples containing pesticide residues and the number of violative residues identified. Such an approach does not adequately convey the likelihood of pesticide residues posing consumer risks since residue regulatory limits are not safety standards and violative pesticide residues rarely constitute residues of health concern. It is more appropriate to develop estimates of actual dietary exposure to pesticides and to compare such estimates to established toxicological criteria such as the Chronic Reference Dose (RfD). The U.S. Food and Drug Administration’s (FDA) Total Diet Study (TDS) previously provided such information but last published its findings in 1995 to estimate dietary exposure to pesticides detected between 1986 and 1991. This paper provides updated estimates of dietary exposure to pesticides in the United States using the most recent TDS findings on pesticide residues. A total of 77 specific pesticides were detected from market basket samples of 2240 TDS food items analyzed by FDA in 2004 and 2005. All estimated exposures to the 77 pesticides for the General US population were well below chronic RfD levels. Only 3 of the 77 pesticides showed exposures greater than 1 % of chronic RfDs, while 14 showed exposures between 0.1 and 1 % of chronic RfDs and 19 had exposures between 0.01 and 0.1 % of chronic RfDs. The remaining 41 pesticides had exposures below 0.01 % of chronic RfDs. Compared with 1986–1991 findings, dietary exposure to six environmentally persistent chlorinated hydrocarbon insecticides were reduced by factors of 47 to 96 % in 2004–2005. Exposures to 15 different population subgroups were estimated and indicated that children, particularly two year-olds, frequently receive higher exposures to pesticide residues in their diets than do adults. Chronic dietary exposure to pesticides in the diet, according to results of the FDA’s 2004–2005 TDS, continue to be at levels far below those of health concern. Consumers should be encouraged to eat fruits, vegetables, and grains and should not fear the low levels of pesticide residues found in such foods.

Scientific Opinion on nitrofurans and their metabolites in food

Nitrofurans are antimicrobial agents not authorised for use in food-producing animals in the European Union. Nitrofurans are rapidly metabolised, occurring in animal tissues as protein-bound metabolites. The European Commission requested EFSA to provide a scientific opinion on the risks to human health related to the presence of nitrofurans in food and whether a reference point for action (RPA) of 1.0 µg/kg for the marker metabolites is adequate to protect public health. Data on occurrence of nitrofuran marker metabolites in food were extracted from the national residue monitoring plan results and from the Rapid Alert System for Food and Feed (RASFF). The CONTAM Panel concluded that these data were too limited to carry out a reliable human dietary exposure assessment. Instead, human dietary exposure was calculated for a scenario in which a single nitrofuran marker metabolite is present at 1.0 µg/kg in foods of animal origin, excluding milk and dairy products. The mean chronic dietary exposure for this worst-case scenario would range from 3.3 to 8.0 and 1.9 to 4.3 ng/kg b.w. per day for toddlers and adults, respectively. Nitrofurans and their marker metabolites, generally, are genotoxic and carcinogenic and, also, have non-neoplastic effects in animals. Margins of exposure (MOEs) were calculated at 2.0 × 105 or greater for carcinogenicity and at 2.5 × 103 or greater for non-neoplastic effects. The CONTAM Panel concluded that it is unlikely that exposure to food contaminated with nitrofuran marker metabolites at or below 1.0 µg/kg is a health concern. A scenario in which foods are considered to be contaminated with semicarbazide, from use of carrageenan as a food additive, at 1 µg/kg was used to assess whether it is appropriate to apply the RPA to foods of non-animal origin; MOEs of greater than 104 calculated for non-neoplastic effects do not indicate a health concern.

Parental trophic exposure to three aromatic fractions of polycyclic aromatic hydrocarbons in the zebrafish: Consequences for the offspring

In recent decades, PAH emissions due to extensive anthropogenic activities have risen sharply causing considerable pollution of aquatic ecosystems. This pollution represents a threat for organisms, among them are fish. Consequently, prenatal stress can have important repercussions, and may impact survival and population recruitment. To investigate this point, eggs were collected from zebrafish exposed during 6months by trophic route to three aromatic fractions from two different origins, pyrolytic (PY) and petrogenic (light (BAL) and heavy (HFO) fractions) sources. Chronic dietary exposure of the parents was performed at environmentally relevant concentrations (0.3×, 1× and 3×; 1× represents an environmental concentration measured in French estuary). In order to explore the consequences of parental exposure for the next first generation, toxic responses were studied in both embryos and larvae using a multiscale approach. Toxic effects were assessed by looking at hatching success, developmental abnormalities, photomotor response and heartbeat. The level of PAH metabolites and EROD activity in fish larvae were measured to assess exposure to PAHs. Egg production of parents was significantly reduced compared to the Control; hence little information was available for BAL and HFO offspring. The size of larvae from PY parents was found to increase despite a reduced yolk sac compared to Control larvae. Furthermore, a high level of behavioral stress was observed in larvae originating from parents exposed to three-fold the environmental concentration. The cardiac activity was reduced in a concentration-dependent manner for the PY exposure group. No effect was however observed on biotransformation markers (cyp1a, EROD), nor on the level of DNA damage for all PY, BAL and HFO offspring. The absence of significant differences in metabolite levels may indicate a potential early depuration of transferred compounds or no PAH-transmission. The disruptions observed at the individual level in the next generation could impact on the longer-term, surviving population.

Detection of Aflatoxins in Rice Samples

Aflatoxins are natural contaminants of cereals and other commodities throughout the world. Chronic dietary exposure even to low doses of aflatoxins is a known risk factor for liver cancer and effect protein metabolism and immunity. The study was carried out on a 1029 samples of brown rice, 1561 samples of white rice, 33 samples of broken rice, 13 samples of Sella rice, 52 samples of parboiled rice of export quality from Pakistan during the years 2006-2010 for determination of Aflatoxin B1, B2, G1 and G2 by Thin Layer Chromatography. 341 (33.13%) samples of white rice, 350 (22.42%) samples of brown rice, 13 (39.39%) samples of broken rice, 25 (24.27%) samples of Sella rice and 14 (26.92%) samples of parboiled rice were found contaminated with B1. B2 was detected in 33 (3.20%) samples of white rice, 23 (1.47%) samples of brown rice and 1(3.03%) samples of broken rice. While G1 is found in 9 (0.8%) samples of white rice, 57 (3.65%) samples of brown rice, 1 (1.5 %) samples of parboiled rice. Aflatoxin G2 was absent in all samples. DOI: http://dx.doi.org/10.3329/bjsir.v49i3.22134 Bangladesh J. Sci. Ind. Res. 49(3), 189-194, 2014

Chronic dietary exposure to aristolochic acid and kidney function in native farmers from a Croatian endemic area and Bosnian immigrants.

Improvements in agricultural practices in Croatia have reduced exposure to consumption of aristolochic acid-contaminated flour and development of endemic (Balkan) nephropathy. Therefore, it was hypothesized that Bosnian immigrants who settled in an endemic area in Croatia 15-30 years ago would be at lower risk of developing endemic nephropathy because of reduced exposure to aristolochic acid. To test this hypothesis, past and present exposure to aristolochic acid, proximal tubule damage as a hallmark of endemic nephropathy, and prevalence of CKD in Bosnian immigrants were analyzed. In this cross-sectional observational study from 2005 to 2010, 2161 farmers were divided into groups: indigenous inhabitants from endemic nephropathy and nonendemic nephropathy villages and Bosnian immigrants; α-1 microglobulin-to-creatinine ratio >31.5 mg/g and eGFR<60 ml/min per 1.73 m(2) were considered to be abnormal. CKD and proximal tubule damage prevalence was significantly lower in Bosnian immigrants than inhabitants of endemic nephropathy villages (6.9% versus 16.6%; P<0.001; 1.3% versus 7.3%; P=0.003, respectively); 20 years ago, Bosnian immigrants observed fewer Aristolochia clematitis in cultivated fields (41.9% versus 67.8%) and fewer seeds among wheat seeds (6.1% versus 35.6%) and ate more purchased than homemade bread compared with Croatian farmers from endemic nephropathy villages (38.5% versus 14.8%, P<0.001). Both Croatian farmers and Bosnian immigrants observe significantly fewer Aristolochia plants growing in their fields compared with 15-30 years ago. Prior aristolochic acid exposure was associated with proximal tubule damage (odds ratio, 1.64; 95% confidence interval, 1.04 to 2.58; P=0.02), whereas present exposure was not (odds ratio, 1.31; 95% confidence interval, 0.75 to 2.30; P=0.33). Furthermore, immigrant status was an independent negative predictor of proximal tubule damage (odds ratio, 0.40; 95% confidence interval, 0.19 to 0.86; P=0.02). Bosnian immigrants and autochthonous Croats residing in endemic areas are exposed significantly less to ingestion of aristolochic acid than in the past. The prevalence of endemic nephropathy and its associated urothelial cancers is predicted to decrease over time.

Assessment of arsenic in Australian grown and imported rice varieties on sale in Australia and potential links with irrigation practises and soil geochemistry

Chronic dietary exposure to arsenic, particularly the inorganic forms (defined as elemental arsenic, predominantly As3+ and As5+, and all its inorganic compounds except arsine), is a matter of concern for human health. Ingestion of arsenic usually occurs via contaminated water but recent studies show there is also a risk of exposure from food, particularly Asian rice (Oryza sativa). Australia is a rice growing country, contributing around 2% of the world rice trade, and a large proportion of the population consumes rice regularly. In the present study we investigated concentrations of arsenic in both Australian grown and imported rice on sale in Australia and examined the potential links with irrigation practises and soil geochemistry. The results indicated a wide spread of arsenic levels of 0.09–0.33mgkg−1, with Australian grown Arborio and sushi varieties of O. sativa containing the highest mean value of ∼0.22mgkg−1. Arsenic levels in all samples were below the 1mgkg−1 limit set by Food Standards Australia New Zealand.

Gut microbiota-dependent trimethylamine N-oxide (TMAO) pathway contributes to both development of renal insufficiency and mortality risk in chronic kidney disease.

Trimethylamine-N-oxide (TMAO), a gut microbial-dependent metabolite of dietary choline, phosphatidylcholine (lecithin), and l-carnitine, is elevated in chronic kidney diseases (CKD) and associated with coronary artery disease pathogenesis. To both investigate the clinical prognostic value of TMAO in subjects with versus without CKD, and test the hypothesis that TMAO plays a direct contributory role in the development and progression of renal dysfunction. We first examined the relationship between fasting plasma TMAO and all-cause mortality over 5-year follow-up in 521 stable subjects with CKD (estimated glomerular filtration rate, <60 mL/min per 1.73 m(2)). Median TMAO level among CKD subjects was 7.9 μmol/L (interquartile range, 5.2-12.4 μmol/L), which was markedly higher (P<0.001) than in non-CKD subjects (n=3166). Within CKD subjects, higher (fourth versus first quartile) plasma TMAO level was associated with a 2.8-fold increased mortality risk. After adjustments for traditional risk factors, high-sensitivity C-reactive protein, estimated glomerular filtration rate, elevated TMAO levels remained predictive of 5-year mortality risk (hazard ratio, 1.93; 95% confidence interval, 1.13-3.29; P<0.05). TMAO provided significant incremental prognostic value (net reclassification index, 17.26%; P<0.001 and differences in area under receiver operator characteristic curve, 63.26% versus 65.95%; P=0.036). Among non-CKD subjects, elevated TMAO levels portend poorer prognosis within cohorts of high and low cystatin C. In animal models, elevated dietary choline or TMAO directly led to progressive renal tubulointerstitial fibrosis and dysfunction. Plasma TMAO levels are both elevated in patients with CKD and portend poorer long-term survival. Chronic dietary exposures that increase TMAO directly contributes to progressive renal fibrosis and dysfunction in animal models.

Scientific Opinion on Chloramphenicol in food and feed

Chloramphenicol is an antibiotic not authorised for use in food-producing animals in the European Union (EU). However, being produced by soil bacteria, it may occur in plants. The European Commission asked EFSA for a scientific opinion on the risks to human and animal health related to the presence of chloramphenicol in food and feed and whether a reference point for action (RPA) of 0.3 μg/kg is adequate to protect public and animal health. Data on occurrence of chloramphenicol in food extracted from the national residue monitoring plan results and from the Rapid Alert System for Food and Feed (RASFF) were too limited to carry out a reliable human dietary exposure assessment. Instead, human dietary exposure was calculated for a scenario in which chloramphenicol is present at 0.3 μg/kg in all foods of animal origin, foods containing enzyme preparations and foods which may be contaminated naturally. The mean chronic dietary exposure for this worst-case scenario would range from 11 to 17 and 2.2 to 4.0 ng/kg b.w. per day for toddlers and adults, respectively. The potential dietary exposure of livestock to chloramphenicol was estimated to be below 1 μg/kg b.w. per day. Chloramphenicol is implicated in the generation of aplastic anaemia in humans and causes reproductive/hepatotoxic effects in animals. Margins of exposure for these effects were calculated at 2.7 × 105 or greater and the CONTAM Panel concluded that it is unlikely that exposure to food contaminated with chloramphenicol at or below 0.3 μg/kg is a health concern for aplastic anaemia or reproductive/hepatotoxic effects. Chloramphenicol exhibits genotoxicity but, owing to the lack of data, the risk of carcinogenicity cannot be assessed. The CONTAM Panel concluded that, when applied to feed, the current RPA is also sufficiently protective for animal health and for public health, arising from residues in animal derived products.

γ-Butyrobetaine Is a Proatherogenic Intermediate in Gut Microbial Metabolism of L-Carnitine to TMAO

L-carnitine, a nutrient in red meat, was recently reported to accelerate atherosclerosis via a metaorganismal pathway involving gut microbial trimethylamine (TMA) formation and host hepatic conversion into trimethylamine-N-oxide (TMAO). Herein, we show that following L-carnitine ingestion, γ-butyrobetaine (γBB) is produced as an intermediary metabolite by gut microbes at a site anatomically proximal to and at a rate ∼1,000-fold higher than the formation of TMA. Moreover, we show that γBB is the major gut microbial metabolite formed from dietary L-carnitine in mice, is converted into TMA and TMAO in a gut microbiota-dependent manner (like dietary L-carnitine), and accelerates atherosclerosis. Gut microbial composition and functional metabolic studies reveal that distinct taxa are associated with the production of γBB or TMA/TMAO from dietary L-carnitine. Moreover, despite their close structural similarity, chronic dietary exposure to L-carnitine or γBB promotes development of functionally distinct microbial communities optimized for the metabolism of L-carnitine or γBB, respectively.

Mechanism of 1,3-Dichloropropene-Induced Rat Liver Carcinogenesis

1,3-Dichloropropene (1,3-D) is a soil fumigant used primarily for preplanting control of parasitic nematodes. In a previous chronic dietary exposure study, 1,3-D induced an increased incidence of hepatocellular adenomas in male rats at a dose of 25 mg/kg/day. Although the mechanism for tumor induction in the rat liver by 1,3-D has not been specifically elucidated, available data suggested that the observed liver tumorigenesis was through a nongenotoxic mode of action at the tumor promotion stage. Fischer 344 rats containing preneoplastic lesions were treated (via gavage) with 25 mg/kg/day 1,3-D or 80 mg/kg/day phenobarbital (PB) for 30 days and 60 days, or for 30 days followed by a 30-day recovery period (no compound exposure). Following treatment, placental form glutathione S-transferase (GSTP) positive and GSTP-negative liver focal lesions were quantitated as to size and number. 1,3-D treatment had no effect on GSTP-positive foci number or relative size but significantly increased the number, labeling index, and relative size of GSTP-negative focal lesions (identified by H and E staining) after 30 and 60 days of treatment. Following the 30-day recovery period, the number, labeling index, and relative size of the GSTP-negative lesions in 1,3-D-treated animals returned to control levels. As expected, PB treatment produced an increase in number and relative size of the GSTP-positive lesions. The results of this study are consistent with 1,3-D inducing liver carcinogenesis through a nongenotoxic mode of action by functioning as a tumor promoter specifically through induction of a non-GSTP staining focal hepatocyte population.

Effect of lysine acetylsalicylate on aluminium accumulation and (Na+/K+)ATPase activity in rat brain cortex synaptosomes after aluminium ingestion

Aluminium is neurotoxic in humans and has been implicated in several neurological disorders. Chronic use of buffered aspirins, as aspegic, would likely constitute the major human aluminium uptake source. Low-dose aspirin is beneficial in secondary prevention of cardiovascular events, so it is widely used for long periods of time. We studied if oral administration of aspegic to rats modified the aluminium inhibitory effect on brain (Na+/K+)ATPase due to alteration in synaptosomal membrane aluminium content. Adult male Wistar rats were submitted to sub-acute (1.00g/day during 10 days) and chronic (0.03g/day during 4 months) dietary AlCl3 exposure and/or to aspegic (0.11g/day). The exposure protocol increased the synaptosomal aluminium content especially after a long-term exposure to aluminium and aspegic. Although no alterations were observed in rat body weight gain and adenylate energy charge, the (Na+/K+)ATPase activity was significantly reduced when aluminium was orally administered to rats. The oral administration of aspegic increased the synaptosomal aluminium content and concomitantly enhanced the (Na+/K+)ATPase inhibition. In our exposure protocol the increase in synaptosomal aluminium content correlates with the reduction of the (Na+/K+)ATPase activity.

Safety assessment of animal- and plant-derived amino acids as used in cosmetics.

The Cosmetic Ingredient Review Expert Panel (Panel) reviewed the safety of animal- and plant-derived amino acid mixtures, which function as skin and hair conditioning agents. The safety of α-amino acids as direct food additives has been well established, based on extensive research through acute and chronic dietary exposures and the Panel previously has reviewed the safety of individual α-amino acids in cosmetics. The Panel focused its review on dermal irritation and sensitization data relevant to the use of these ingredients in topical cosmetics. The Panel concluded that these 21 ingredients are safe in the present practices of use and concentration as used in cosmetics.

Correction: Histopathologic Alterations Associated with Global Gene Expression Due to Chronic Dietary TCDD Exposure in Juvenile Zebrafish

Correction: Histopathologic Alterations Associated with Global Gene Expression Due to Chronic Dietary TCDD Exposure in Juvenile Zebrafish

Cumulative dietary exposure to a selected group of pesticides of the triazole group in different European countries according to the EFSA guidance on probabilistic modelling

The practicality was examined of performing a cumulative dietary exposure assessment according to the requirements of the EFSA guidance on probabilistic modelling. For this the acute and chronic cumulative exposure to triazole pesticides was estimated using national food consumption and monitoring data of eight European countries. Both the acute and chronic cumulative dietary exposures were calculated according to two model runs (optimistic and pessimistic) as recommended in the EFSA guidance. The exposures obtained with these model runs differed substantially for all countries, with the highest exposures obtained with the pessimistic model run. In this model run, animal commodities including cattle milk and different meat types, entered in the exposure calculations at the level of the maximum residue limit (MRL), contributed most to the exposure. We conclude that application of the optimistic model run on a routine basis for cumulative assessments is feasible. The pessimistic model run is laborious and the exposure results could be too far from reality. More experience with this approach is needed to stimulate the discussion of the feasibility of all the requirements, especially the inclusion of MRLs of animal commodities which seem to result in unrealistic conclusions regarding their contribution to the dietary exposure.

Scientific Opinion on the risks to human and animal health related to the presence of beauvericin and enniatins in food and feed

Beauvericin and enniatins are mycotoxins produced by various Fusarium species. The European Commission asked EFSA for a scientific opinion on the risk to human and animal health related to the presence of beauvericin and enniatins in food and feed. A total of 12 685 analytical results for beauvericin and enniatins in food, feed and unprocessed grains were evaluated. For the assessment of enniatins, the sum of enniatins A, A1, B and B1 were considered. The most important contributors to the chronic dietary exposure to beauvericin and the sum of enniatins were ‘Grains and grain-based products’, especially ‘Bread and rolls’, ‘Fine bakery wares’ and ‘Pasta (raw)’. Given the lack of relevant toxicity data, a risk assessment was not possible. To obtain some insights in the possible risks of both mycotoxins at the estimated acute dietary exposure levels, these were compared to the LD 50 values of beauvericin and of the drug fusafungine (a mixture of enniatins). For the chronic exposure, an estimate for the LOAEL of fusafungine was considered. The CONTAM Panel concluded that acute exposure to beauvericin and enniatins do not indicate concern for human health. There might be a concern with respect to chronic exposure but no firm conclusion could be drawn, thus relevant in vivo toxicity data are needed to perform a human risk assessment. Animal exposure to beauvericin and enniatins was primarily from consuming cereal grains and cereal by-products. Using the LD 50 values of beauvericin and fusafungine, adverse health effects from the acute exposure to beauvericin and the sum of enniatins for farm and companion animals were unlikely. The chronic exposure for poultry indicated that adverse health effects from beauvericin and enniatins were unlikely. For other considered animals, the lack of LOAELs/NOAELs precluded the estimation of chronic health risk from beauvericin and enniatins.

Histopathologic Alterations Associated with Global Gene Expression Due to Chronic Dietary TCDD Exposure in Juvenile Zebrafish

The goal of this project was to investigate the effects and possible developmental disease implication of chronic dietary TCDD exposure on global gene expression anchored to histopathologic analysis in juvenile zebrafish by functional genomic, histopathologic and analytic chemistry methods. Specifically, juvenile zebrafish were fed Biodiet starter with TCDD added at 0, 0.1, 1, 10 and 100 ppb, and fish were sampled following 0, 7, 14, 28 and 42 d after initiation of the exposure. TCDD accumulated in a dose- and time-dependent manner and 100 ppb TCDD caused TCDD accumulation in female (15.49 ppb) and male (18.04 ppb) fish at 28 d post exposure. Dietary TCDD caused multiple lesions in liver, kidney, intestine and ovary of zebrafish and functional dysregulation such as depletion of glycogen in liver, retrobulbar edema, degeneration of nasal neurosensory epithelium, underdevelopment of intestine, and diminution in the fraction of ovarian follicles containing vitellogenic oocytes. Importantly, lesions in nasal epithelium and evidence of endocrine disruption based on alternatively spliced vasa transcripts are two novel and significant results of this study. Microarray gene expression analysis comparing vehicle control to dietary TCDD revealed dysregulated genes involved in pathways associated with cardiac necrosis/cell death, cardiac fibrosis, renal necrosis/cell death and liver necrosis/cell death. These baseline toxicological effects provide evidence for the potential mechanisms of developmental dysfunctions induced by TCDD and vasa as a biomarker for ovarian developmental disruption.

Early warning signs of endocrine disruption in adult fish from the ingestion of polyethylene with and without sorbed chemical pollutants from the marine environment

Plastic debris is associated with several chemical pollutants known to disrupt the functioning of the endocrine system. To determine if the exposure to plastic debris and associated chemicals promotes endocrine-disrupting effects in fish, we conducted a chronic two-month dietary exposure using Japanese medaka (Oryzias latipes) and environmentally relevant concentrations of microplastic (<1mm) and associated chemicals. We exposed fish to three treatments: a no-plastic (i.e. negative control), virgin-plastic (i.e. virgin polyethylene pre-production pellets) and marine-plastic treatment (i.e. polyethylene pellets deployed in San Diego Bay, CA for 3months). Altered gene expression was observed in male fish exposed to the marine-plastic treatment, whereas altered gene expression was observed in female fish exposed to both the marine- and virgin-plastic treatment. Significant down-regulation of choriogenin (Chg H) gene expression was observed in males and significant down-regulation of vitellogenin (Vtg I), Chg H and the estrogen receptor (ERα) gene expression was observed in females. In addition, histological observation revealed abnormal proliferation of germ cells in one male fish from the marine-plastic treatment. Overall, our study suggests that the ingestion of plastic debris at environmentally relevant concentrations may alter endocrine system function in adult fish and warrants further research.

Low bioavailability of silver nanoparticles presents trophic toxicity to marine medaka (Oryzias melastigma).

Concerns for the potential risks of silver nanoparticles (AgNPs) to aquatic organisms have increased. The present study investigated the trophic transfer of AgNPs from brine shrimp (Artemia salina) nauplii to marine medaka. We found that the aggregated AgNPs (20 and 80 nm) and well dispersed 80-nm AgNPs (stabilized by 20 μM Tween 20) could be readily accumulated by brine shrimp, while far less well-dispersed 20-nm AgNPs were accumulated. The assimilation efficiency (AE) of AgNPs in medaka fed AgNPs-contaminated brine shrimp was low (<6%), resulting in a low trophic transfer efficiency (0.01-0.04) after 28 days of chronic dietary exposure. However, such low bioavailability of dietary AgNPs could inhibit the whole-body Na+/K+-ATPase and superoxide dismutase (SOD) activity in the fish within the first 2 weeks of exposure. Significant (p<0.05, two-way ANOVA) inhibition occurred in the high AgNPs-contaminated brine shrimp treatment over 28 days of chronic exposure. Furthermore, reduced growth and water content percentage were also observed in fish fed high dosages of AgNPs-contaminated brine shrimp. Our study highlighted the potential of trophically available AgNPs in bringing toxicity to the marine fish.

Reframing the Governance of Addictions

The ALICE RAP (Addictions and Lifestyles in Contemporary Europe – Reframing Addictions Project; www. alicerap.eu) is a five year E 10 million endeavour, cofinanced by the European Commission, studying the place of addictions in contemporary Europe. Based on ALICE RAP s new research and its synthesis of existing research, in this editorial, I highlight three themes that can drive a reframing of the governance of addictions. The first theme is that an ecological analysis of addictive substances suggests that humans are active and functional in relation to the drugs thatwe take, rather thanbeing passive and vulnerable (Sullivan & Hagen, 2014). For example, in the story of life over the last 400 million years, one of the developments has been the battle between plants, and the animals that eat them. Of many defence mechanisms, plants produce secondarymetabolites, including nicotine, morphine, and cocaine, potent neurotoxins that evolved because they punished and deterred consumption by plant-eating animals. Counterbalancing this, animals have evolved to counter-exploit the products of these hundreds of millions of years of research by plants to inhibit and kill their own parasites by subsisting on a mixed diet of palatable and toxic plants, trading off diet quality (and thus growth) for what is termed enemy-reduced or enemy-free space. This also applies to humans. Amongst Congo basin hunter gatherers, the quantity of cigarettes smoked is titrated against intestinal worm burden – the higher the worm burden, the greater the number of cigarettes smoked. Further, when treated with the anthelmintic drug, abendazole, the number of cigarettes smoked is reduced (Roulette et al., 2014). In another example, the presence of ethanol within ripe fruit suggests low-level but chronic dietary exposure for all fruit-eating animals, with volatilized alcohols from fruit potentially serving in olfactory localization of nutritional resources (Dudley, 2014). The same seems to apply to humans, since, whereas primate ancestors living 16–21 million years ago could not effectively metabolize consumed ethanol, by 6–12 million years ago, human s last common ancestor with gorillas and chimpanzees had evolved a digestion fully capable ofmetabolizing consumed ethanol, at levels found in fermenting fruits (Brenner, 2013). That humans are active and functional in relation to the drugs that we take, including alcohol and nicotine, has at least three implications. First, prohibition and “war(s) on drugs” are likely to fail, because substance use is not “caused” by biological frailty in people in general; second, understanding the ecological contexts and dynamics of drug use may point to new preventive and clinical approaches – the above example of anti-worm treatment reducing cigarette use; third, active and functional speak to potency as being a primary driver of drug use and related harm. This brings us to the second theme, toxicological analysis. For example, margin of Exposure (MoE) analysis compares the ratio of a toxic dose of a drug with the dose consumed (Lachenmeier & Rehm, 2014). A MoE of 1 implies consuming the toxic dose; a MoE of 100 implies consuming 1/100 toxic dose. The European Food Safety Authority (EFSA) sets a MoE of 1,000 for carcinogens whose toxic dose is assessed in humans and whose consumption is voluntary (unlike drinking water). Such aMoE does not imply that consumption is safe, only low risk. The MoE for the consumption of alcohol by European adults is assessed at 1.3 when based on animal studies in which the equivalent does increases death rates by 10 %, and 1.0 when based on human studies with a 1.5 % increased risk of death from liver cirrhosis. This means that European adults consume alcohol at the toxic dose, or 1,000 times the dose were the EFSA guidelines applied to alcohol (EFSA does not assess alcohol). This, together with the fact that the risk of premature death under the age of 70 years for an alcohol-related cause increases linearly with the dose of alcohol consumption (Rehm, Lachenmeier &Room, 2014) implies that the potency of the alcohol we consume is far too high. The strength of alcoholic products could be reduced without consumer preferences being compromised (Lachenmeier, Kanteres & Rehm, 2014). In another example, almost all of the nicotine humans consume (West, Brown&Beard, 2014) is in the form of the SUCHT, 60 (6), 2014, 309 – 311

Chronic dietary exposure of zebrafish to PAH mixtures results in carcinogenic but not genotoxic effects.

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants that can be present at high levels as mixtures in polluted aquatic environments. Many PAHs are potent mutagens and several are well-known carcinogens. Despite numerous studies on individual compounds, little is known about the toxicity of PAHs mixtures that are encountered in environmental situations. In the present work, zebrafish were continuously fed from 5 days post-fertilisation to 14 months post-fertilisation (mpf) with a diet spiked with fractions of either pyrolytic (PY), petrogenic light oil (LO), or petrogenic heavy oil (HO) origin at three concentrations. A decrease in survival was identified after 3 mpf in fish fed with the highest concentration of HO or LO, but not for PY. All PAH fractions caused preneoplastic and neoplastic disorders in long-term-exposed animals. Target tissues were almost exclusively of epithelial origin, with the bile duct epithelium being the most susceptible to chronic exposure to all PAH fractions, and with germ cells being the second most responsive cells. Significantly higher incidences of neoplasms were observed with increasing PAH concentration and exposure duration. The most severe carcinogenic effects were induced by dietary exposure to HO compared to exposure to LO or PY (45, 30 and 7 %, respectively, after 9 to 10 months of exposure to an intermediate concentration of PAHs). In contrast, earliest carcinogenic effects were detected as soon as 3 mpf after exposure to LO, including the lowest concentration, or to PY. PAH bioactivation and genotoxicity in blood was assessed by ethoxyresorufin-O-deethylase activity quantification and comet and micronuclei assays, respectively, but none of these were positive. Chronic dietary exposure of zebrafish to PAH mixtures results in carcinogenotoxic events that impair survival and physiology of exposed fish.