Search

The Norwegian Scientific Committee for Food Safety performed the present assessment of the differences between organic and conventional foods and food production on plant health, animal health and welfare and human health at the request of the Norwegian Food Safety Authority. The work was divided into five parts: (I) Plant health and plant production, (II) Animal health and welfare, (III) Human health - nutrition and contaminants, (IV) Human health – hygiene and pathogens and (V) Human health - pesticide residues. The assessments are based on review of the scientific literature. Separate literature searches were performed and one or two expert reviewers from the five working groups examined the literature. Detailed descriptions of the searches and the publication selection are included in the five reports. In addition, relevant assessments for the purpose, prepared by international and national scientific bodies, were included. There are few Norwegian studies on organic food production and food products and their impact on plant health, animal health and welfare, and human health. The assessments therefore had to rely on scientific studies from abroad. The relevance of these studies for conditions under which Norwegian food and feed production take place varies. There were large variations in study design, exposure (both type and time of exposure), and the measured outcomes among the studies included. Apart from the Norwegian monitoring program on pesticide residue in food, there is no systematic national surveillance on the content of nutrients and contaminants in food and feed from organic and conventional food production. This preludes any assessment of possible differences on the intake of nutrients and contaminants of Norwegian consumers from food of the two production systems. For plant health and plant production, most studies concluded that crop losses due to plant diseases, plant pests and weeds are higher in organic than in conventional production. Richness and abundance of pollinating insects and natural enemies of harmful insects are higher in organic than in conventional farming. In general, there are small differences in content of nutrients, secondary plant metabolites, and other plant constituents, except for organic berries and fruits where higher levels of dry matter, ascorbic acid and antioxidant activity have been found. In conventionally grown wheat, there are higher levels of protein than in organically grown wheat. Contamination of cereals with Fusarium-mycotoxins is widespread. Results from comparison of mycotoxin contamination in organic and conventional cereals vary. While most studies found no difference in DON content, the majority of the remaining studies reported lower levels in organic than in conventional cereals. Most studies showed that organically produced cereals contained lower levels of theT-2 and HT-2 toxins than conventionally grown cereals. Some studies showed higher mycotoxin contamination in organic than in conventional apple products, while other studies reported similar level of contamination. Only few comparative studies of quality in organic and conventional seeds and seed potatoes have been published. Therefore, it is not possible to conclude on quality differences. For animal health and welfare, it was concluded that the differences between animal health and welfare regulations in Norway for organic and conventional animal production are less than in most other countries. The presence of antimicrobial resistant bacteria in both organic and conventional production systems is very low in Norway. The difference between the two production systems in proportional rate of antimicrobial resistant bacteria is small and insignificant. There are no differences in disease occurrence between organic and conventional farming except for less clinical mastitis and more milk fever in organic dairy herds. For cattle, the increased access to pasture and outdoor areas, the use of group housing for milk feeding calves and the increased space allowance for growing cattle is positive for animal welfare in organic production. However, grouping of young calf, suckling for three days, as well as pasturing, could have some hygienic challenges due to more exposure for pathogens and parasites. For sheep and goats, the differences in animal health and welfare are small. For pigs, the access to outdoor area and provision of roughage is positive for animal health and welfare in organic production, but prevention and control of parasites and pathogens from wildlife, as well as predators may be a challenge. For poultry, the increased space allowance in organic production for broilers and layers, use of slow growing breeds, the use of roughage and natural light is beneficial for both health and welfare. There are no data to support positive effects on welfare and health of small flock sizes. Access to outdoor areas is positive for animal welfare, but increases the risk of parasites, predators and infectious diseases or subclinical infections with zoonotic agents (example: influenza and Newcastle disease). For honey bees, the ban in organic farming against feeding bee colonies with pollen supplements in periods with low pollen availability, as well as the ban (EU regulation) against the disinfection of equipment with caustic soda, produces welfare challenges compared to conventional honey production. Concerning feed, the nutrient contents, bioactive secondary plant compounds, as well as contaminants such as mycotoxins and pesticide residues may differ between organically and conventionally produced plants for feed. The impact on animal health and welfare is sparsely documented. Keyw: For human health, the main conclusions are that consistent evidence of clear positive or negative effects on human health as a result of consuming an organic diet, in comparison with a conventional diet has not been presented. There are reported indications of health benefits from organic food on risk of atopic diseases in children and a positive impact of organic diets on general health in animal models. The evidence is not sufficient to draw any conclusion. None of the studies on human health reported negative health effects from organic food consumption compared with conventional foods. There are some differences in concentrations of nutrients and other bioactive compounds in organic, compared with conventional foods. However, differences are mostly small and no differences have been found in e.g. biomarkers of antioxidant status, hence the relevance for health in humans on a well-balanced diet is uncertain. There is currently no firm evidence to conclude that organic products are more or less microbiologically safe than conventionally produced foods, and it may be assumed that any possible differences between organic and conventional productions concerning the prevalence of pathogens or antimicrobial resistance in Norway will be small or insignificant. Organic foods contain lower amounts of pesticides than conventional food, and lower urinary concentrations of pesticide metabolites in children have been observed from abroad. In Norway, the estimated exposure to pesticide residues in conventional food is low, and well below what is likely to result in adverse health effects. The finding of pesticide residues which exceeds established regulatory limits in a minority of tested samples, is not considered to result in adverse health effects. Available data suggest that the combined exposure to multiple pesticide residues is not likely to result in increased human health risk.

The Norwegian Scientific Committee for Food Safety (Vitenskapskomiteen for mattrygghet, VKM) has on request of The Norwegian Food Safety Authority performed a risk assessment of furan intake in the Norwegian population based on the most recent national food consumption surveys. National occurrence data of furan concentrations in food were preferentially used in the risk assessment. When national data were lacking, VKM has used occurrence data of furan from other countries. The assessment has been performed by the VKM Panel on Food Additives, Flavourings, Processing Aids, Materials in Contact with Food and Cosmetics and the VKM Panel on Contaminants. Furan is a volatile and lipophilic compound formed in a variety of heat-treated commercial foods and contributes to the sensory properties of the product. The substance has been found in a number of foods such as coffee, canned and jarred foods including baby food containing meat and various vegetables. High concentrations of furan have been found in coffee and the presence of furan in jarred baby food and infant formulae has received much attention since such products may be the sole diet for many infants. The occurrence of furan in a variety of foods suggests that there are multiple routes of furan formation rather than a single mechanism. The Norwegian Food Safety Authority has in 2008 and 2009 collected data on furan concentrations in different food products sold on the Norwegian market (Norwegian Food Safety Authority, 2008). In 2011, the Norwegian Food Safety Authority also decided to analyse commercial porridges for infants and children sold on the Norwegian market, to see if furan could be detected in such products. The calculated furan exposures from food and beverages are based on data from the nationally representative food consumption surveys; Spedkost, Småbarnskost, Ungkost and Norkost. The consumption for each relevant food or food category in the dietary surveys were multiplied with the corresponding mean furan concentrations and totalled for each individual. The liver is the main target organ for furan toxicity both in mice and rats, but the rat is the most sensitive species. A dose-dependent increase in hepatocellular adenomas and carcinomas was observed in mice and rats, and an increase in the incidence of cholangiocarcinomas was observed in rat liver. Cholangiocarcinomas in male and female rats were the most sensitive toxicological end point observed in rodents. On the basis of the available data, VKM considers that rat cholangiocarcinomas may be relevant for assessing human risk from furan. Available in vivo data with furan indicate that a reactive metabolite, most likely cis-2-butene1,4-dial (BDA), is formed and that this metabolite can react with DNA and induce mutations. To VKM’s knowledge, no in vivo studies on genotoxicity of BDA have been performed, but BDA was found to be genotoxic in several in vitro tests. VKM therefore considers that a genotoxic mechanism in furan-induced carcinogenesis cannot be excluded and the substance was assessed as a genotoxic carcinogen. VKM used the Margin of Exposure (MOE) approach in this risk assessment. The suitability of different studies on cholangiocarcinomas for dose-response modelling was considered. The 9-month interim evaluation of a 2-year study from NTP (1993) was chosen because it demonstrates a dose-response relationship. From this study, a point of departure of 0.02 mg/kg bw/day was chosen, based on a benchmark dose lower bound (BMDL10) of 0.14 mg furan/kg bw/day and a correction factor of 7 for shorter than full life-time (2 years) study duration. For 6-, 12- and 24-month-old children, the main source of furan exposure is jarred baby food. For 4-, 9- and 13-year-old children, the major food source to the furan exposure is breakfast cereals. In adults, the major contribution to the furan exposure is coffee. The highest furan exposure was calculated for 12-month-old infants and ranged from 0.62-1.51 µg/kg bw/day. In adults the furan exposure ranged from 0.27-0.82 µg/kg bw/day. For mean exposure among infants, children and adolescents, the MOE-values ranged from 29 in 12-month-infants to 2000 in the 13-year-old adolescents. Among high consumers in these groups, the MOE-values ranged from 13 to 400. In adults, the corresponding MOE-values ranged from 59 to 74 for mean furan exposure and from 24 to 26 for high exposure. It should be noted that this risk assessment of furan contains notable uncertainties and limitations. The use of the 9-month interim study in rats including a correction factor of 7 to derive a point of departure, instead of a full life-time study (2-year) study, likely overestimates the hazard of furan. A possible over-diagnosis of the cholangiocarcinomas, due to the similarities in histopathology between cholangiofibrosis and cholangiocarcinomas in rats, may overestimate the hazard. There are also limitations in assessing food consumption and furan content in foods, leading to uncertainties in estimation of furan exposure. VKM considers that the current exposure to furan in all age groups, particularly among infants and children, is of health concern.

The present report is based on data from the 2010 EFSA Report on pesticide residues in food, the Norwegian monitoring programmes 2007-2012 and data from peer reviewed literature and governmental agencies. It is a challenge to perform quantitative estimates and comparative studies of residue levels due to large variation in the measured levels, and the large number of different pesticides present in the samples. Thus, the focus is on the frequency of observed contaminations in relation to regulatory limits and to present examples to illustrate the variation in residue values and number of detected substances. Pesticide residues in conventional and organic products: Of the 12,168 samples (plant- and animal products) in the 2010 EU-coordinated programme, 1.6% exceeded the respective maximum residue level (MRL) values, and 47.7% had measurable residues above the limit of quantification (LOQ), but below or at the MRL. Of the 1168 samples analysed in Norway in 2012 (from both imported and domestic products), 1.9% exceeded MRL and 53% contained measurable pesticide residues. Direct comparison of these values is however not possible, since they contain different types of food samples, and are analysed for a different number of pesticides. When organic and conventional samples from fruit, vegetables and other plant products in the 2010 EU-coordinated programme were compared, 4.2% of the conventional and 1.0% of the organic samples exceeded the MRL values, while 43.2% of the conventional and 10.8% of the organic samples had measurable residues below or at the MRL value. Most of the pesticide residues detected in organic samples are not permitted for use in organic farming. Of the 624 organic samples analysed in Norway 2007 - 2012, 0.2% (one sample) had residues exceeding MRL, while measurable residues were detected in 1.8% of the samples (11 samples). Conventional products were often found to contain different pesticides while most organic samples were found to contain few or only one type of pesticide. Lack of data on pesticide residue levels of organic samples in the EU-coordinated programme, and few Norwegian samples do not allow for a quantitative comparison of pesticide residue levels in organic and conventional samples. Comparative estimation of pesticide residues faces a number of challenges and uncertainties. However, it seems unquestionable based on available data that organic plant products contain fewer and substantially lower amounts of pesticide residues than conventional products. Health risk associated with pesticide residues: The general level of pesticide residues in both conventional and organic food is low, and well below what is likely to result in adverse health effects. This conclusion is based on the comparison of estimated dietary exposure with toxicological reference values i.e. acceptable daily intake (ADI) for chronic effects, and acute reference dose (ARfD) for acute effects. The finding of pesticide residues that exceeds established regulatory limits in a minority of tested samples is not considered to represent a health risk. When dietary exposure that was estimated in six different food commodities in the 2010 EUcoordinated programme was compared with their relevant reference values, EFSA concluded that for 79 of 18243 conventionally grown fruit and vegetable samples, a short-term acute consumer health risk could not be excluded. The conclusion was based on the exceeding of ARfD. None of these 79 samples were organic. It is important to also consider that the exceeding of the acute reference value only occurred in 0.4% of the samples and that the scenario used for acute intake assessment is conservative, suggesting that the toxicological implications are limited. This is also reflected in the chronic exposure assessment, where none of the samples were found to exceed the toxicological reference value ADI. Dietary exposure assessments on the basis of Norwegian samples of apples, tomatoes, carrots, strawberries and lettuce did not show an exceeding of any toxicological reference value. Combined exposure and cumulative risk assessment of pesticide residues: No generally accepted methodology is at present established for cumulative risk assessment of combined exposure to pesticide residues. Available data suggest however that combined exposure is not likely to result in increased human health risk.

Request from the Norwegian Food Safety Authority (NFSA) In September 2013, the Norwegian Food Safety Authority requested VKM to update relevant parts of the benefit-risk assessment of fish in the Norwegian diet published by VKM in 2006. The background for the request was new knowledge and data on the content of some nutrients and contaminants both for wild and farmed fish since 2006. The proportion of vegetable ingredients used in farmed fish feed has in recent years increased, and new national dietary surveys for adults and children have been conducted. The Norwegian Food Safety Authority referred to VKM’s report from 2006, which pointed out that the positive impact of fish consumption on public health was especially due to the content of polyunsaturated fatty acids and vitamin D in fish. Further, VKM concluded that the contaminants that could pose a potential risk to public health through fish consumption mainly were methylmercury, dioxins and dioxin-like PCBs (dl-PCBs). Grey Literature Skare et al.; EJNFS, 5(4): 260-266, 2015; Article no.EJNFS.2015.023 261 The request included a reassessment of fish consumption in Norway with focus on specific nutrients; n-3 fatty acids (eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), docosahexaenoic acid (DHA), vitamin D, and the minerals iodine and selenium, and on specific contaminants; mercury, dioxins and dl-PCBs. VKM was asked to address the main changes in the use of raw materials in farmed fish feed and how these affect the levels of nutrients, mercury, dioxins and dl-PCBs and in fish feed. Further, VKM was asked to address to what extent levels of nutrients and contaminants in fish have changed since 2006, to describe these changes and estimate the human intake of the substances in question on the basis of recent dietary data. VKM was also requested to consider the benefits of eating fish with regard to the intake of nutrients and the risks associated with the intake of mercury, dioxins and dl-PCBs and comment on whether this change the conclusions from the report in 2006. Additionally, on the basis of updated knowledge, VKM was asked to comment whether other substances, like pesticide and residues of veterinary medicinal products, could affect the conclusions with regard to the impact on public health. The Norwegian Food Safety Authority and the Directorate of Health will use the updated assessment as a basis for public recommendations concerning the consumption of fish and fish products. How VKM has Addressed the Request The VKM appointed a working group consisting of VKM members and external experts to answer the request. Several of the scientific panels of VKM reviewed the report during its preparation. The Scientific Steering Committee of VKM has given their final assessment and approval of the current report. In the current report, VKM has mainly used data from national surveillance and monitoring programs for nutrient and contaminant concentrations in fish feed, farmed fish and wild caught fish, but occurrence data have also been derived from peer reviewed articles. VKM has estimated fish consumption in three population groups (2-year-olds, adults and pregnant women). The estimated fish consumption was compared to national dietary guidelines. To assess health effects of fish consumption, the current estimated fish intakes were also compared with assessments done by recognised international bodies and results from epidemiological studies addressing possible associations between fish consumption and specific health outcomes. Literature searches were done to identify relevant epidemiological studies. VKM has not systematically assessed reviews or meta-analyses nor individual studies for weight of evidence, but merely summarised the studies retrieved from the literature search. It was considered being beyond the scope of this assessment to review individual studies included in reviews or meta-analyses. Furthermore, based on current fish consumption in the various population groups, intake of nutrients and exposure to contaminants from fish were estimated. For benefit characterisation of the specific nutrients the estimated nutrient intake was compared with national recommendations of nutrients intake and for EPA and DHA a comparison was also done with European recommendations. For risk characterization of contaminant exposure from fish, VKM used health based guidance values set by international risk assessment bodies (WHO, EFSA). VKM noted that the request from NFSA was restricted to fish, whereas the VKM report in 2006 included both fish and other seafood. VKM focused on specific nutrients and contaminants as requested by the NFSA. In addition, VKM also commented on other substances that could affect the risk assessment, such as residues of veterinary medicinal products including residues of antibiotics, new contaminants from fish feed like the pesticide endosulfan, polycyclic aromatic hydrocarbons (PAHs), mycotoxins, the synthetic antioxidants ethoxyquin, butylhydroxyanisole (BHA) and butylhydroxytoluene (BHT), as well as environmental contaminants like brominated flame retardants and perfluorated organic compounds. Skare et al.; EJNFS, 5(4): 260-266, 2015; Article no.EJNFS.2015.023

Determination of toxicity of complex mixtures has been proposed to be one of the most important challenges for modern toxicology. In this study we performed genome wide transcriptome profiling to assess potential toxicant induced changes in gene regulation in zebrafish embryos following parental exposure to two natural mixtures of persistent organic pollutants (POPs). The mixtures used were extracted from burbot (Lota lota) liver originating from two lakes (Lake Mjøsa and Lake Losna) belonging to the same freshwater system in Norway. The dominating groups of contaminants were polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane metabolites (DDTs). Because both mixtures used in the present study induced similar effects, it is likely that the same toxicants are involved. The Mjøsa mixture contains high levels of PBDEs while this group of pollutants is low in the Losna mixture. However, both mixtures contain substantial concentrations of PCB and DDT suggesting these contaminants as the predominant contributors to the toxicity observed. The observed effects included phenotypic traits, like embryo production and survival, and gene transcription changes corresponding with disease and biological functions such as cancer, reproductive system disease, cardiovascular disease, lipid and protein metabolism, small molecule biochemistry and cell cycle. The changes in gene transcription included genes regulated by HNF4A, insulin, LH, FSH and NF-κB which are known to be central regulators of endocrine signaling, metabolism, metabolic homeostasis, immune functions, cancer development and reproduction. The results suggest that relative low concentrations of the natural mixtures of POPs used in the present study might pose a threat to wild freshwater fish living in the lakes from which the POPs mixtures originated.

A series of studies have assessed the occurrence, levels, and potential adverse effects of persistent organic pollutants (POP) in fish from Lake Mjosa. In this lake, high levels of various POP were detected in biota. Fish from the nearby Lake Losna contain background levels of POP and served as reference (controls) in these studies. Significantly higher prevalence of mycobacteriosis and pathological changes were documented in burbot (Lota lota) from Mjosa compared to burbot from Losna. Further, transcriptional profiling identified changes in gene expression in burbot from Mjosa compared to burbot from Losna associated with drug metabolism enzymes and oxidative stress. POP extracted from burbot liver oil from the two lakes was used to expose zebrafish (Danio rerio) during two consecutive generations. During both generations, POP mixtures from both lakes increased the rate of mortality, induced earlier onset of puberty, and skewed sex ratio toward males. However, opposite effects on weight gain were found in exposure groups compared to controls during the two generations. Exposure to POP from both lakes was associated with suppression of ovarian follicle development. Analyses of genome-wide transcription profiling identified functional networks of genes associated with weight homeostasis, steroid hormone functions, and insulin signaling. In human cell studies using adrenocortical H295R and primary porcine theca and granulosa cells, exposure to lake extracts from both populations modulated steroid hormone production with significant difference from controls. The results suggest that POP from both lakes may possess the potential to induce endocrine disruption and may adversely affect health in wild fish.

Source at http://dx.doi.org/10.9734/EJNFS/2016/23233 The present benefit and risk assessment of breastmilk and contaminants in breastmilk was initiated by the Norwegian Scientific Committee for Food Safety (VKM). The overall objective is to provide a balanced assessment of the benefits of breastmilk against the possible risks from exposure to contaminants in breastmilk with focus on Norwegian conditions. The aim is to contribute to a foundation for decision-makers when providing recommendations on the length of exclusive and partial breastfeeding. The composition of breastmilk is tailored for the needs of the newborn. Provided that the nutritional needs of the mother are met during pregnancy and breastfeeding, breastmilk covers all the nutritional requirements of the infant the first months of life, with the exception of vitamin D. Breastmilk also contains a number of specialised components, including growth factors, factors with anti-microbial and anti-inflammatory properties and selected immunological components whichboost the maturation of the infant’s immune system. Infant formula fulfils the infant’s established nutritional needs, but does not provide the specific protective factors which are present only in breastmilk. However, studies over the last four decades have shown that polluting chemicals have accumulated in the environment, biomagnified in the food chain, are in our bodies, and consequently in breastmilk. The levels of lipid-soluble persistent contaminants in the foetus, the newborn child and in breastmilk largely reflect the amount of these in the mother’s body. Thus, breastmilk contains nutrients and protective immunological factors which have a positive effect on infant health, but may also contain contaminants. Particularly lipid-soluble and persistent contaminants accumulate in the infant during breastfeeding. This has contributed to a debate among experts agreeing that breastfeeding is beneficial, but discussing the advisable length of breastfeeding.

Obesity is reaching epidemic proportions worldwide, and is associated with chronic illnesses such as diabetes, cardiovascular disease, hypertension and dyslipidemias (metabolic syndrome). Commonly held causes of obesity are overeating coupled with a sedentary lifestyle. However, it has also been postulated that exposure to endocrine disrupting chemicals (EDCs) may be related to the significant increase in the prevalence of obesity and associated diseases. In the present study, developmental and reproductive effects of lifelong exposure to environmentally relevant concentrations of two natural mixtures of persistent organic pollutants (POPs) were investigated using classical and molecular methods in a controlled zebrafish model. The mixtures used were extracted from burbot ( Lota lota ) liver originating from freshwater systems in Norway (Lake Mjosa and Lake Losna). The concentration of POPs in the zebrafish ranged from levels detected in wild fish (Lake Mjosa and Lake Losna), to concentrations reported in human and wildlife populations. Phenotypic effects observed in both exposure groups included (1) earlier onset of puberty, (2) elevated male/female sex ratio, and (3) increased body weight at 5 months of age. Interestingly, genome-wide transcription profiling identified functional networks of genes, in which key regulators of weight homeostasis (PPARs, glucocoricoids, CEBPs, estradiol), steroid hormone functions (glucocoricoids, estradiol, NCOA3) and insulin signaling (HNF4A, CEBPs, PPARG) occupied central positions. The increased weight and the regulation of genes associated with weight homeostasis and insulin signaling observed in the present study suggest that environmental pollution may affect the endocrine regulation of the metabolism, possibly leading to increased weight gain and obesity.

In the present study, developmental and reproductive effects of lifelong exposure to environmental relevant concentrations of two natural mixtures of persistent organic pollutants (POP) were investigated using classical and molecular methods in a controlled zebrafish model. The mixtures used were extracted from burbot (Lota lota) liver originating from freshwater systems in Norway: one mixture with high levels and one mixture with background levels of polybrominated diphenyl ethers (PBDE), polychlorinated biphenyls (PCB), and dichlorodiphenyltrichloroethane metabolites (DDT). The concentration of POP measured in the zebrafish ranged from levels detected in wild fish from Lake Mjøsa to concentrations reported in human and wildlife populations, indicating that the experimental fish were exposed to concentrations comparable with wild fish. Phenotypic effects observed in both exposure groups included earlier onset of puberty, increased male/female sex ratio, and differences in body weight at 5 mo of age. Interestingly, genome-wide transcription profiling showed changes in regulation of genes involved in endocrine signaling and growth. The transcriptomics changes include key regulator genes for steroid hormone functions (ncoa3), and growth (c/ebp, ncoa3). The effects observed in the experimental zebrafish model raise the question whether chemical pollution represents a risk to reproductive health of wild fish inhabitating the freshwater system.

Dead and dying glaucous gulls (Larus hyperboreus) were collected on Bjørnøya in the Barents Sea in 2003, 2004 and 2005. Autopsies of the seabirds only explained a clear cause of death for three (14%) of the 21 birds. A total of 71% of the birds were emaciated. Liver and brain samples were analysed for organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ether (PBDEs), hexabromocyclododecanes (HBCDs) and mercury (Hg). High levels of SigmaOCPs, SigmaPCBs, SigmaPBDEs and alpha-HBCD were found in liver and brain. Compared to the dead and dying glaucous gulls found 1989, the congeners' composition tended to change toward more persistent compounds in the 2003-2005 samples. The brain levels of OCPs and PCBs did not differ between 1989 and 2003-2005, while the liver levels were significantly lower. The brain/liver ratio for PCB and PBDE significantly decreased with halogenations of the molecule, indicating a clear discrimination of highly halogenated PCBs and PBDEs entering the brain. There was further a clear negative correlation between contaminant concentrations and body condition. The brain levels were not as high as earlier published lethal levels of p,p'-DDE or PCB. However, more recent studies reported a range of sub-lethal OCP- and PCB-related effects in randomly sampled glaucous gulls. An additional elevation of pollutants due to emaciation may increase the stress of the already affected birds. The high brain levels of OCP, PCB and PBDE of present study might therefore have contributed to the death of weakened individuals of glaucous gull.

Abstract This study was conducted to investigate the applicability of an in vitro technique for maturation, fertilization, cleavage, and growth to blastocysts of bovine oocytes to investigate reproductive toxicologic effects. During maturation, the oocytes were exposed to the di- ortho -substituted PCB congener 2,2′,4,4′,5,5′-CB (PCB 153) in the three concentrations 0.84 ng/mL, 8.4 ng/mL, and 84 ng/mL or to the non- ortho -substituted PCB congener 3,3′4,4′,5-CB (PCB 126) in the three concentrations 1.006 pg/mL, 10.06 pg/mL, and 100.6 pg/mL and compared with control groups. PCB 153 had no effect on maturation but resulted in a reduced proportion of oocytes that cleaved at the highest concentration. There were no differences in blastocyst development among groups. PCB 126 resulted in a reduction in maturation percentage at the highest concentration and in blastocyst development at all concentrations. These results demonstrated adverse effects of PCB congeners on bovine oocytes and showed that this system can be used to evaluate toxic effects on oocytes and preimplantation-stage embryos.

Responses in flounder (Platichthys flesus) towards benzo [a]pyrene (BaP), 2,3,3',4,4',5-hexachlorobiphenyl (PCB-156), and cadmium (Cd) were investigated in time-course and dose-response studies of selected biomarkers. Measurements of biliary fluorescent BaP metabolites and hepatic concentrations of PCB-156 and cadmium showed that the injected toxicants were rapidly m obilized from the muscle to the liver, but a depot effect was indicated in the highest dose groups of BaP and PCB-156 (12 mg kg(-1) bodyweight). Clearest biomarker responses were found in the induction of hepatic cytochrome P450 1A (CYP1A) enzymes as a response towards BaP and PCB-156 exposure. Maximum induction of CYP1A dependent 7-ethoxyresorufin O-deethylase (EROD) activity was observed after 2 and 8 days in BaP and PCB-156-treated flounder, respectively. Positive dose-effect relationships were observed towards both compounds, but the CYP1A induction was more persistent with PCB exposure than with BaP exposure. In Cd-exposed fish, the hepatic level of metallothionein responded more slowly with highest levels observed after 16 days in the time-study. In the combined BaP + Cd treatment, the CYP1A induction was only slightly suppressed. Aspartate aminotransferase in serum appeared to be responsive towards BaP, but also towards the acetone vehicle in controls in the first part of the exposure period. Hematocrit as well as hepatic activities of aldrin epoxidase, glutathione S-transferase, and UDP-glucuronyl transferase were not responsive to any treatm ent in the present study. In general, the results demonstrate that selected biom arkers in flounder are responsive to PAH, PCB, and heavy metal pollutant exposure, indicating the applicability of this species in future environmental pollution monitoring programmes.

Flounder (Platichthys flesus L.) and Atlantic cod (Gadus morhua L.) were subjected to caging at polluted sediments in a Norwegian fjord (Sorfjorden) for a period of 3 months. Three caging sites were located close to metal smelters, whereas a fourth site was located 30 km away as a reference. In sediment samples, polyaromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and heavy metals were elevated at the innermost sites (1, 2 and 3) compared with the reference location (site 4). In fish, the biliary levels of fluorescent aromatic compounds (FACs) were elevated 5–20 fold in both species at the polluted sites. A two-fold difference in heavy metal levels was observed in cod (site 2 vs. 4), whereas no differences were seen in flounder. Pesticides bioaccumulated in a diffuse manner at all sites. In flounder at the innermost sites, plasma aspartate aminotransferase (AST) and hepatic cytochrome P450 1A (CYP1A) dependent 7-ethoxyresorufin O-deethylase (EROD) activity were elevated 4–5 and 5–10 fold, respectively, compared with the reference site. Both of these biomarkers were significantly correlated with FACs levels. For other biomarkers, the site effect was more marginal. The biomarkers seemed in general more responsive in flounder than in cod. The present study demonstrates biomarker measurements in caged fish as a promising approach for evaluating accumulation and effects of pollutants in marine teleosts.

Persistent organic pollutants (POP) occur as mixtures in nature and it is difficult to predict the toxicity of such mixtures based on knowledge about toxicity and mechanisms of action for single compounds. The present knowledge on the combined toxic effects and modes of actions of exposure to mixtures is limited. Thus, the scientifically based hazard and risk assessment of POP requires analytical and toxicological data from studies with environmental mixtures of POP. The application of genome wide transcription profiling in toxicology, in combination with classical endpoints, will improve the current understanding of the mechanisms of toxic processes. Furthermore, gene expression data may be useful in establishing new hypothesis and discovering new biomarkers for known toxicity as well as not yet recognized toxicity endpoints. In the present study, developmental and reproductive effects of lifelong exposure to environmental relevant concentrations of two natural mixtures of POP were investigated using classical and molecular methods in a controlled zebrafish model. The mixtures used were extracted from burbot (Lota lota) liver originating from freshwater systems in Norway: one mixture with high levels and one mixture with background levels of polybrominated diphenyl ethers (PBD), polychlorinated biphenyls (PCB), and DDT. The concentration of POP in the zebrafish ranged from levels detected in wild fish from Lake Mjosa, to concentrations reported in human and wildlife populations. Phenotypic effects observed in both exposure groups included (1) reduced survival, (2) earlier onset of puberty, (3) increased male/female sex ratio, and (4) differences in body weight at 5 mo of age. Interestingly, genome-wide transcription profiling showed changes in regulation of genes involved in endocrine signaling and growth. The transcriptomics changes included (1) key regulator genes for steroid and thyroid hormone functions (cga, ncoa3), (2) insulin signaling and metabolic homeostasis (pik3r1, pfkfb3, ptb1), and (3) p53 activation (mdm4). The effects observed in the experimental zebrafish model raise the question of whether chemical pollution represents a risk to the reproductive health of wild fish inhabiting the freshwater system.

Many persistent organic pollutants are known to have endocrine-disrupting effects in several aquatic and terrestrial species. In this regard, hydroxylated metabolites of polychlorinated biphenyls (OH-PCBs) represent serious health and environmental concern because they are shown to act agonistic or antagonistic at hormone receptors (HRs) or to cause hormone-receptor-mediated responses. In the present study, salmon primary hepatocytes were used to study alterations in an estrogen signaling pathway resulting from exposure to four hydroxylated (4OH-CB 107, 4OH-CB146, 4OH-CB187, and 3OH-CB138) metabolites of PCB at different concentrations using quantitative real-time polymerase chain reaction. The effects of the PCB metabolites were compared to the mRNA expression in 17alpha-ethynylestradiol (EE2)-treated cells. Concentration-specific increase of vitellogenin (Vtg) mRNA transcription after exposure to OH-PCBs was observed. Decreased mRNA transcription was observed for zona radiata protein (Zr-protein) and cytochrome P450 side-chain cleavage (P450scc) enzyme. For estrogen receptor beta (ERbeta), the mRNA expression pattern was OH-PCB-metabolite congener-specific. A novel aspect of this study is that OH-PCBs produced effects on hepatic steroidogenic pathways by targeting the StAR protein and P450scc genes. Given that endocrine toxicology research mainly has focused on estrogenicity involving direct ER-mediated effects and that steroidogenic enzyme and proteins are highly tissue- and cell-type-specific and controlled by different promoters and second-messenger pathways, the present findings provide potential new targets for interaction with xenobiotics such as hydroxylated congeners of certain chemicals. The quantitative expression patterns of hepatic and extrahepatic steroidogenic genes and proteins after exposure to environmental contaminants are the subject of systematic investigations in our laboratory.

The time trend in the DDT contamination of the marine environment in a Norwegian fjord where DDT has been used extensively in local fruitgrowing, has been studied for 10 years following the DDT ban. Residues of ∑-DDT (p,p′-DDT + 1.11p,p′-DDE + 1.11p,p′-TDE (DDD). The factor 1.11 is added to correct for the lower molecular weight) in 225 liver samples of seven sedentary fish species showed a downward trend during the period 1972 to 1982. The decrease in ∑-DDT illustrates the effectiveness of the 1970 ban on its use in Norway. The highest 1982 mean level of ∑-DDT was found in the liver of cod (Gadus morhua) (1237 μg/kg, wet weight, range 191–3845 μg/kg) and was about 1/3 of the corresponding 1972 residue level. The decrease of ∑-DDT was less rapid in the liver of the cod and the haddock (Melanogrammus aeglefinus) (half-life time 5.0 years with a 95% confidence limit of 2.3 years) than in the fish species sea scorpion (Myoxocephalus scorpius), cat fish (Anarhichas lupus), ballan wrasse (Labrus berggylta) and lemon sole (Microstomus kitt) (half-life time 2.6 years with a 95% confidence limit of 0.8 years). Cod and haddock have a substantially higher fat content in the liver compared to the other fish species. A half-life time of 3–5 years for biologically available DDT residues is suggested to apply generally to Nordic marine environments. Unmetabolized DDT constitute a smaller proportion of ∑-DDT in 1982 than in the previous years. However, a great variation between species and individuals was found. PCB contamination in the fish was low, and reflect a Norwegian baseline contamination. The highest 1982 mean level of PCB residues was found in cod liver (454 μg/kg, wet weight, range 175–1073 μg/kg) which was about 1/3 of the 1972 value. The levels of ∑-DDT and PCBs were correlated to fish weight in the cod. These two types of residues were mutually correlated over all weights. No correlation was found between the fat content of the liver and the residue level of organochlorine chemicals within the species. Only low levels of contamination by hexachlorobenzene (HCB), α-, γ-HCH and ∑-chlordane were found in 1982. The highest levels were found in cod liver (HCB 6–26; γ-HCH 6–16; α-HCH 4–140;∑-chlordane = oxychlordane + transnonachlor 38–220 μg/kg, wet weight). The levels of organochlorines in fish from a Norwegian fjord were generally low and not believed to have any toxicological implications.

The clinical effect, residues in milk and toxicological properties of a non-commercial formulation of malathion used as an ectoparasitic agent on cattle were investigated. The results show that the malathion preparation has a desired clinical effect. The maximum concentration of malathion in milk after topical application of 5 g malathion was 0.054 μg/ml 4–6 h post-treatment, and declined to 0.005 and 0.002 μg/ml 24 and 48 h post-treatment, respectively. Totally 0.006–0.03 % of the applied dose was excreted in the milk. No toxic effect, measured as inhibition of the cholinesterases in erythrocytes and plasma, could be detected after therapeutic use of malathion. The pharmacokinetic evaluation after 2.5 g intravenous administration of malathion, indicated that the kinetics could probably be described by a multicompartment model.