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Comment on "Contaminant levels in Norwegian farmed Atlantic salmon (Salmo salar) in the 13-year period from 1999 to 2011" by Nøstbakken et al
... Owing to the accumulation on the adipose tissue, the chemicals create a massive impact over top predators of the food chain (Taylor, 2003). Organophosphates and pyrethroids are also found to cause a serious decline to shrimp, crab, and other vertebrate populations (Ruzzina et al., 2015;Thursby et al., 2018). Many herbicides show potential damage to the central nervous system and are often found to be carcinogenic in many cases (Fig. 2). ...
Different discoveries of agrochemical-based agrotechnologies and their application replacing the traditional practices have become very successful to improve the production of food and combat hunger in an exponentially growing population. It had also resulted to boost-up agroeconomy across the world. However, different research surveys have revealed a higher trend of accumulation of toxicants in different spheres of the environment posing deleterious effects to aerial, aquatic, and terrestrial health. Most of the harmful effects are found because of nonjudicious uses of agrochemicals, which, by the way of biotransformation, cause several diseases and damage biodiversity. Several government proceedings have made legislations against the use of persistent organic chemicals and recommended the use of biodegradable chemicals for a better greener environment. In order to ensure higher production and maintain quality, several interdisciplinary approaches have been adopted, including organic farming, traditional knowledge, and the use of genetically modified crops to combat poisoning of the environment and to create a greener environment for future generations.
... Owing to the accumulation on the adipose tissue, the chemicals create a massive impact over top predators of the food chain (Taylor, 2003). Organophosphates and pyrethroids are also found to cause a serious decline to shrimp, crab, and other vertebrate populations (Ruzzina et al., 2015;Thursby et al., 2018). Many herbicides show potential damage to the central nervous system and are often found to be carcinogenic in many cases (Fig. 2). ...
Agriculture started around 9000 BC and developed globally with the discoveries and application of several
agrobiotechnological tools all over the world. However, the innovations cannot be demarcated from any sorts of
socioeconomic, political, and institutional networks in which agriculture is circumscribed. These innovations follow a
continuous trend in evolution putting emphasis to the wide development of agrochemicals and technology embedded to it
(Partel et al., 2019). Agrochemicals are used mainly for purposes such as the improvement of farm production (fertilizers
and other agrochemicals), controlling of pests (pesticides), and preservation of farm products (preservatives). Owing to
improper labeling, storage, and injudicious usage, agrochemicals can cause serious poisoning of environmental health,
which directly affects human health. Growing with the concept of the 3E’s (ecology, ethics, and economy), sustainability
demands a pivotal role in agriculture management (Ferreira et al., 2018). However, the question remains how and to
what extent the utilization of agrochemicals is sustainable? These types of questions are considerably provoked and
often debatable (Karandish, 2019). Positions in the consideration have engrained to both those who believe in the use
of agrochemical products in sustainable agriculture and those who do not. The debate points out a shift in agriculture
paradigm that emphasizes the potency of using fertilizers and agrochemicals for higher yield in order to meet the demand
of a growing population and improvement to the beneficiaries on the other side (Carvalho, 2017). High-yield results in a
good supply of food to the population and provides a good way to improve the standard of living among farmers (Garibaldi
et al., 2016). On the other hand, it causes detrimental environmental degradation while providing a new resolution to
combat hunger (Bruun et al., 2017; Vorley and Keeney, 1998).
Sustainable development is liable to the proper and prudent consumption of natural resources for the advancement of
the human race and mankind (Flint, 2013). So it implements development and maintenance of ecosystem health for present
and future generations (Xuan, 2018). However, most of the developmental techniques are often consigned to achieve
economic profits and in lieu gift a serious depletion causing anthropogenic disturbances (Strange and Bayley, 2008).
Therefore, adoptions of several interdisciplinary and holistic approaches are required for proper utilization of resources
under socioeconomic conditions (Mukute et al., 2018; O’Brien et al., 2009).The dilemma is further decisive in India because the country supports approximately 16% of world’s total human
population and 2.5% of the total geographical area (UNEP, 2001), creating immense pressure on consumption of natural
resources. Population growth united with a prevalent occurrence of paucity and unjustified policies and supervision of
natural resources is predictable to an effect in unnecessary demands on the stock of natural resources. Such demand is
approximated to be supreme worldwide by the year 2020 (World Bank, 2008). Escalating importance on the effort of
exhaustive agricultural procedures with high-yielding varieties reflects to be a critical problem as it necessitates large-scale
use of chemical fertilizers. Besides, the restraints to bring more area under farming and insufficiency of several essential
nutrients in soils have enforced the extensive use of chemicals in agriculture (Planning Commission of India, 2011).
... Residues from these chemicals, plus natural toxins from harmful algal blooms, dioxins, and PCBs, put the quality of coastal waters and the aquaculture production under pressure of contamination (SEP 2015). Although there has been a decrease of farmed salmon contamination by organic chemicals over the years, still the consumption of fish is a matter of concern and advice on intake limitation has been given to consumers Ruzzina et al. 2015). ...
Agrochemicals have enabled to more than duplicate food production during the last century, and the current need to increase food production to feed a rapid growing human population maintains pressure on the intensive use of pesticides and fertilizers. However, worldwide surveys have documented the contamination and impact of agrochemical residues in soils, and terrestrial and aquatic ecosystems including coastal marine systems, and their toxic effects on humans and nonhuman biota. Although persistent organic chemicals have been phased out and replaced by more biodegradable chemicals, contamination by legacy residues and recent residues still impacts on the quality of human food, water, and environment. Current and future increase in food production must go along with production of food with better quality and with less toxic contaminants. Alternative paths to the intensive use of crop protection chemicals are open, such as genetically engineered organisms, organic farming, change of dietary habits, and development of food technologies. Agro industries need to further develop advanced practices to protect public health, which requires more cautious use of agrochemicals through prior testing, careful risk assessment, and licensing, but also through education of farmers and users in general, measures for better protection of ecosystems, and good practices for sustainable development of agriculture, fisheries, and aquaculture. Enhanced scientific research for new developments in food production and food safety, as well as for environmental protection, is a necessary part of this endeavor. Furthermore, worldwide agreement on good agriculture practices, including development of genetically modified organisms (GMOs) and their release for international agriculture, may be urgent to ensure the success of safe food production. © 2017 John Wiley & Sons Ltd and the Association of Applied Biologists.
Given scientific and public debate about optimal diet to prevent cardiovascular disease, and interest in diet and other chronic diseases, we propose that following a few simple dietary principles would reduce chronic disease incidence.
Nutrition research has been criticized for focusing on individual nutrients and foods, treated like drug therapy. With a few important exceptions, clinical trials of supplemental nutrients have not shown benefit. Although highly specific nutrition information is elusive, diet patterns have provided consistent answers, important for public health. Observational cohort studies have found that some dietary patterns are reported with high reliability over long periods and predict future cardiovascular and other inflammatory-related diseases. Two randomized clinical trials confirmed this finding. There are many common features of Mediterranean and prudent diets, particularly the plant-centered aspect, coupled with variety of foods eaten. A dietary pattern characterized by high fruit, vegetable, legume, whole grain, nut, berry, seed, and fish intakes, and possibly by intakes of dairy, coffee, tea, chocolate, and alcohol (not in excess), but low meat and detrimentally processed foods is associated with reduced incidence of cardiovascular disease and rates of noncardiovascular, noncancer chronic inflammatory-related mortality.
A plant-centered diet may be broadly recommended.
Background:
Environmental pollutants such as dioxins and PCBs, heavy metals, and organochlorine pesticides are a global threat to food safety. In particular, the aquatic biota can bioaccumulate many of these contaminants potentially making seafood of concern for chronic exposure to humans.
Objectives:
The main objective was to evaluate trends of contaminant levels in Norwegian farmed Atlantic salmon in light of the derived tolerable intakes.
Methods:
Through an EU-instigated surveillance programme, the Norwegian Food Safety Authority (NFSA) has between 1999 and 2011 collected more than 2300 samples of Norwegian farmed Atlantic salmon (Salmo salar) for contaminant analyses. The fillets of these fish were homogenised and analysed for dioxins, PCBs, heavy metals and organochlorine pesticides.
Results:
The levels of the contaminants mercury, arsenic, dioxins, dioxin-like PCBs and DDT in Norwegian farmed salmon fillet have decreased during our period of analyses. The levels of cadmium, lead and several organochlorine pesticides were too close to the limit of quantification to calculate time trends. For PCB6 and quantifiable amounts of pesticides, except DDT, stable levels were observed.
Conclusion:
The contaminant levels in Norwegian farmed salmon have generally decreased between 1999 and 2011. Excluding other dietary sources, the levels of dioxins and dioxin-like PCBs in 2011 allowed consumption of up to 1.3kg salmon per week to reach the tolerable weekly intake. The group of contaminants which was the limiting factor for safe consumption of Norwegian farmed salmon, based on currently established TWI values, is the sum of dioxins and dioxin-like PCBs.
For decades, studies of endocrine-disrupting chemicals (EDCs) have challenged traditional concepts in toxicology, in particular the dogma of "the dose makes the poison," because EDCs can have effects at low doses that are not predicted by effects at higher doses. Here, we review two major concepts in EDC studies: low dose and nonmonotonicity. Low-dose effects were defined by the National Toxicology Program as those that occur in the range of human exposures or effects observed at doses below those used for traditional toxicological studies. We review the mechanistic data for low-dose effects and use a weight-of-evidence approach to analyze five examples from the EDC literature. Additionally, we explore nonmonotonic dose-response curves, defined as a nonlinear relationship between dose and effect where the slope of the curve changes sign somewhere within the range of doses examined. We provide a detailed discussion of the mechanisms responsible for generating these phenomena, plus hundreds of examples from the cell culture, animal, and epidemiology literature. We illustrate that nonmonotonic responses and low-dose effects are remarkably common in studies of natural hormones and EDCs. Whether low doses of EDCs influence certain human disorders is no longer conjecture, because epidemiological studies show that environmental exposures to EDCs are associated with human diseases and disabilities. We conclude that when nonmonotonic dose-response curves occur, the effects of low doses cannot be predicted by the effects observed at high doses. Thus, fundamental changes in chemical testing and safety determination are needed to protect human health.
Synthetic chemicals currently used in a variety of industrial and agricultural applications are leading to widespread contamination of the environment. Even though the intended uses of pesticides, plasticizers, antimicrobials, and flame retardants are beneficial, effects on human health are a global concern. These so-called endocrine-disrupting chemicals (EDCs) can disrupt hormonal balance and result in developmental and reproductive abnormalities. New in vitro, in vivo, and epidemiological studies link human EDC exposure with obesity, metabolic syndrome, and type 2 diabetes. Here we review the main chemical compounds that may contribute to metabolic disruption. We then present their demonstrated or suggested mechanisms of action with respect to nuclear receptor signaling. Finally, we discuss the difficulties of fairly assessing the risks linked to EDC exposure, including developmental exposure, problems of high- and low-dose exposure, and the complexity of current chemical environments.
The incidence of the insulin resistance syndrome has increased at an alarming rate worldwide, creating a serious challenge to public health care in the 21st century. Recently, epidemiological studies have associated the prevalence of type 2 diabetes with elevated body burdens of persistent organic pollutants (POPs). However, experimental evidence demonstrating a causal link between POPs and the development of insulin resistance is lacking.
We investigated whether exposure to POPs contributes to insulin resistance and metabolic disorders.
Sprague-Dawley rats were exposed for 28 days to lipophilic POPs through the consumption of a high-fat diet containing either refined or crude fish oil obtained from farmed Atlantic salmon. In addition, differentiated adipocytes were exposed to several POP mixtures that mimicked the relative abundance of organic pollutants present in crude salmon oil. We measured body weight, whole-body insulin sensitivity, POP accumulation, lipid and glucose homeostasis, and gene expression and we performed microarray analysis.
Adult male rats exposed to crude, but not refined, salmon oil developed insulin resistance, abdominal obesity, and hepatosteatosis. The contribution of POPs to insulin resistance was confirmed in cultured adipocytes where POPs, especially organochlorine pesticides, led to robust inhibition of insulin action. Moreover, POPs induced down-regulation of insulin-induced gene-1 (Insig-1) and Lpin1, two master regulators of lipid homeostasis.
Our findings provide evidence that exposure to POPs commonly present in food chains leads to insulin resistance and associated metabolic disorders.
By disrupting the action of androgens during gestation, certain chemicals present in food, consumer products, and the environment can induce irreversible demasculinization and malformations of sex organs among male offspring. However, the consequences of simultaneous exposure to such chemicals are not well described, especially when they exert their actions by differing molecular mechanisms.
To fill this gap, we investigated the effects of mixtures of a widely used plasticizer, di(2-ethylhexyl) phthalate (DEHP); two fungicides present in food, vinclozolin and prochloraz; and a pharmaceutical, finasteride, on landmarks of male sexual development in the rat, including changes in anogenital distance (AGD), retained nipples, sex organ weights, and malformations of genitalia. These chemicals were chosen because they disrupt androgen action with differing mechanisms of action.
Strikingly, the effect of combined exposure to the selected chemicals on malformations of external sex organs was synergistic, and the observed responses were greater than would be predicted from the toxicities of the individual chemicals. In relation to other hallmarks of disrupted male sexual development, including changes in AGD, retained nipples, and sex organ weights, the combined effects were dose additive. When the four chemicals were combined at doses equal to no observed adverse effect levels estimated for nipple retention, significant reductions in AGD were observed in male offspring.
Because unhindered androgen action is essential for human male development in fetal life, these findings are highly relevant to human risk assessment. Evaluations that ignore the possibility of combination effects may lead to considerable underestimations of risks associated with exposures to chemicals that disrupt male sexual differentiation.
To assess the health risks associated with exposure to 2,3,7,8-tetrachlorodebenzo- p -dioxin (TCDD), we studied the effects of a relatively low dose of TCDD on the male reproductive system of rats, using the experimental protocol of T. A. Mably et al. (1992, Toxicol. Appl. Pharmacol. 114, 97–107, 108–117, 118–126), and searched for the most sensitive and reliable among several indices of TCDD toxicity. Pregnant Holtzman rats were given a single oral dose of 0, 12.5, 50, 200, or 800 ng TCDD/kg body weight on gestational day (GD) 15, and male offspring were sacrificed on postnatal day (PND) 49 or 120. GC-MS analysis of the abdominal fat tissue and testis clearly showed increased amounts of TCDD in these offspring. However, there was no TCDD effect on body weight of offspring. There were no changes on testicular or epididymal weights by TCDD administration, even at the 800-ng/kg dose in rats sacrificed on either PND 49 or 120. In addition, TCDD administration resulted in no changes in daily sperm production or sperm reserve at any of the doses used. However, the weight of the urogenital complex, including the ventral prostate, was significantly reduced at doses of 200 and 800 ng TCDD/kg in rats sacrificed on PND 120. Moreover, the anogenital distance (AGD) of male rats sacrificed on PND 120 showed a significant decrease in the groups receiving doses greater than 50 ng TCDD/kg. TCDD administration resulted in no apparent dose-dependent changes in levels of either serum testosterone or luteinizing hormone. Interestingly, reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed that, in the ventral prostates of the PND 49 group, TCDD administration resulted in both a dose-dependent increase in 5&agr;-reductase type 2 (5&agr;R-II) mRNA level and a dose-dependent decrease in androgen receptor (AR) mRNA level. These results suggest that low-dose TCDD administration had a greater effect on the development of the external genital organs and ventral prostate than on development of the testis and other internal genital organs. Moreover, it is highly suggested that the decrease in the size of the ventral prostate by maternal TCDD exposure might be due to decreased responsiveness of the prostate to androgen due to an insufficient expression level of androgen receptor during puberty.
Aquaculture's pressure on forage fisheries remains hotly contested. This article reviews trends in fishmeal and fish oil use in industrial aquafeeds, showing reduced inclusion rates but greater total use associated with increased aquaculture production and demand for fish high in long-chain omega-3 oils. The ratio of wild fisheries inputs to farmed fish output has fallen to 0.63 for the aquaculture sector as a whole but remains as high as 5.0 for Atlantic salmon. Various plant- and animal-based alternatives are now used or available for industrial aquafeeds, depending on relative prices and consumer acceptance, and the outlook for single-cell organisms to replace fish oil is promising. With appropriate economic and regulatory incentives, the transition toward alternative feedstuffs could accelerate, paving the way for a consensus that aquaculture is aiding the ocean, not depleting it.
The low potency of many man-made estrogenic chemicals, so-called xenoestrogens, has been used to suggest that risks arising from exposure to individual chemicals are negligible. Another argument used to dismiss concerns of health effects is that endogenous steroidal estrogens are too potent for xenoestrogens to contribute significantly to estrogenic effects. Using a yeast reporter gene assay with the human estrogen receptoralpha, we tested these ideas experimentally by assessing the ability of a combination of 11 xenoestrogens to affect the actions of 17ss-estradiol. Significantly, each xenoestrogen was present at a level well below its no-observed-effect concentration (NOEC). To derive accurate descriptions of low effects, we recorded concentration-response relationships for each xenoestrogen and for 17ss-estradiol. We used these data to predict entire concentration-response curves of mixtures of xenoestrogens with 17ss-estradiol, assuming additive combination effects. Over a large range of concentrations, the experimentally observed responses decisively confirmed the model predictions. The combined additive effect of the 11 xenoestrogens led to a dramatic enhancement of the hormone's action, even when each single agent was present below its NOEC. Our results show that not even sub-NOEC levels of xenoestrogens can be considered to be without effect on potent steroidal estrogens when they act in concert with a large number of similarly acting chemicals. It remains to be seen to what degree these effects can be neutralized by environmental chemicals with antiestrogenic activity. Nevertheless, potential human and wildlife responses induced by additive combination effects of xenoestrogens deserve serious consideration.
Low-level exposure to some persistent organic pollutants (POPs) has recently become a focus because of their possible link with the risk of diabetes.
Cross-sectional associations of the serum concentrations of POPs with diabetes prevalence were investigated in 2,016 adult participants in the National Health and Nutrition Examination Survey 1999-2002. Six POPs (2,2',4,4',5,5'-hexachlorobiphenyl, 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin, 1,2,3,4,6,7,8,9-octachlorodibenzo-p-dioxin, oxychlordane, p,p'-dichlorodiphenyltrichloroethane, and trans-nonachlor) were selected, because they were detectable in >or=80% of participants.
Compared with subjects with serum concentrations below the limit of detection, after adjustment for age, sex, race and ethnicity, poverty income ratio, BMI, and waist circumference, diabetes prevalence was strongly positively associated with lipid-adjusted serum concentrations of all six POPs. When the participants were classified according to the sum of category numbers of the six POPs, adjusted odds ratios were 1.0, 14.0, 14.7, 38.3, and 37.7 (P for trend < 0.001). The association was consistent in stratified analyses and stronger in younger participants, Mexican Americans, and obese individuals.
There were striking dose-response relations between serum concentrations of six selected POPs and the prevalence of diabetes. The strong graded association could offer a compelling challenge to future epidemiologic and toxicological research.
Background: The last several decades have seen an enormous increase in the development and manufacture of different organic chemicals that have proven useful for many aspects of contemporary life. The question is the degree to which some of these chemicals cause harm to human beings. Objective: This book is directed at the goal of identifying organic chemicals that, while useful in many regards, pose risks to human health because of their biological activity and often their persistence. Discussion: The various chapters in this book are directed at the effects of organic chemicals on the various organ systems. Conclusions: While recognizing the wonderful benefits that have come from the development and use of many organic chemicals, serious adverse human health effects have occurred because of inadequate testing prior to use and ineffective steps to prevent release of the chemicals into air, food, water, and the environment, resulting in exposure and disease in humans. It is urgent that more effective ways be found to ensure the safety of organic chemicals, no matter how useful they may be, before they are produced and released into the environment.
This paper reports a wide-scope screening for detection and identification of pesticides and polycyclic aromatic hydrocarbons (PAHs) in feeds and fish tissues. QuEChERS sample treatment was applied, using freezing as an additional clean-up. Analysis was carried out by gas chromatography coupled to hybrid quadrupole time-of-flight mass spectrometry with atmospheric pressure chemical ionization (GC-(APCI) QTOF MS). The qualitative validation was performed for over 133 representative pesticides and 24 PAHs at 0.01 and 0.05 mg/kg. Subsequent application of the screening method to aquaculture samples made it possible to detect several compounds from the target list, such as the chlorpyrifos-methyl, pirimiphos-methyl, ethoxyquin, among others. Light PAHs (≤ 4 rings) were found in both animal and vegetable samples. The reliable identification of the compounds was supported by accurate mass measurements and the presence of at least two representative m/z ions in the spectrum together with the retention time of the peak, in agreement with the reference standard. Additionally, the search was widened to include other pesticides for which standards were not available, thanks to the expected presence of the protonated molecule and/or molecular ion in the APCI spectra. This could allow the detection and tentative identification of other pesticides different from those included in the validated target list.
Persistent organic pollutants (POPs) are lipophilic compounds that accumulate mainly in adipose tissue. Recent human evidence links low dose POPs to an increased risk of type 2 diabetes (T2D). As humans are contaminated by POP mixtures and POPs possibly have inverted U-shaped associations with T2D, critical methodological issues arise in evaluating human findings. This review summarizes epidemiological results on chlorinated POPs and T2D, and relevant experimental evidence. It also discusses how features of POPs can affect inferences in humans. The evidence as a whole suggests that, rather than a few individual POPs, it is background exposure to POP mixtures -including organochlorine pesticides and polychlorinated biphenyls- that can increase T2D risk in humans. Inconsistent statistical significance for individual POPs may arise due to differences in POP mixtures between populations. Differences in the observed shape of the dose-response curves may reflect an inverted U-shaped association secondary to mitochondrial dysfunction or endocrine-disruption. Finally, we examine the relationship between POPs and obesity. There is evidence in animal studies that low dose POP mixtures are obesogenic. However, relationships between POPs and obesity in humans have been inconsistent. Adipose tissue plays a dual role of promoting T2D and providing a relatively safe place to store POPs. Large prospective studies with serial measurements of a broad range of POPs, adiposity, and clinically-relevant biomarkers are needed to disentangle the interrelationships among POPs, obesity and the development of T2D. Also needed are laboratory experiments that more closely mimic real-world POP doses, mixtures, and exposure duration in humans.
Monograph Working Group Members V J Cogliano (USA)–Chair; K Aronson, H Tryphonas (Canada); Y L Guo (Taiwan, China); M Machala (Czech Republic); E C Bonefeld-Jørgensen, K Vorkamp (Denmark) J P Cravedi, B Le Bizec, J F Narbonne (France); H Esch (Germany); P Cocco, F Merletti (Italy); R Vermeulen (unable to attend; Netherlands); A Agudo (Spain); N Johansson (Sweden); H Fiedler, N Hopf (Switzerland); H P Glauert, R A Herbert, M O James, G Ludewig, L Robertson, A Ruder, N Walker (USA)
This article describes the development, validation and application of a rapid screening method for the detection and identification of undesirable organic compounds in aquaculture products. A generic sample treatment was applied without any purification or preconcentration step. After extracting the samples with acetonitrile/water 80:20 (0.1% formic acid), the extracts were centrifuged and directly injected in the LC-HRMS system, consisting of ultra-high performance liquid chromatography coupled to hybrid quadrupole time-of-flight mass spectrometry (UHPLC-QTOF MS). A qualitative validation was carried out for over 70 representative compounds, including antibiotics, pesticides and mycotoxins, in fish feed and fish fillets spiked at 20 µg/Kg and 100 µg/Kg. At the highest level, the great majority of compounds were detected (using the most abundant ion, typically the protonated molecule) and unequivocally identified (based on the presence of two accurate-mass measured ions). At the 20 µg/Kg level, many contaminants could already be detected although identification using two ions was not fully reached for some of them, mainly in fish feed due to the complexity of this matrix. Subsequent application of this screening methodology to aquaculture samples made it possible to find several compounds from the target list, such as the antibiotic ciprofloxacin, the insecticide pirimiphos-methyl and the mycotoxins fumonisin B2 and zearalenone. A retrospective analysis of accurate-mass full-spectrum acquisition data provided by QTOF MS was also made, without neither reprocessing nor injecting the samples. This allowed the detection and tentative identification of other organic undesirables different than those included in the validated list.
The effects of low doses of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on the reproductive system of male offspring rats were examined. The dams were treated subcutaneously 2 weeks prior to mating and throughout mating, pregnancy, and lactation. They received an initial loading dose of 25, 60, or 300 ng TCDD/kg body wt, followed by a weekly maintenance dose of 5, 12, or 60 ng TCCD/kg body wt (TCDD 25/5, TCDD 60/12, and TCDD 300/60). Three dams per group were killed on Gestation Day 21 and the fetuses were removed. The concentration of TCDD in the maternal liver and fat was measured. After birth, developmental landmarks in male rats were monitored. At weaning, the concentration of TCDD in the offspring liver and testis was determined. Effects on male reproduction were studied on Postnatal Days (PND) 70 and 170. At weaning, the concentration of TCDD in the offspring liver was 0.24, 0.39, and 1.78 ng/g in the TCDD 25/5, TCDD 60/12, and TCDD 300/60 groups, respectively. In the testes, the concentration of TCDD was 0.25 ng/g in the TCDD 25/5 and TCDD 60/12 groups and 0.28 ng/g in the TCDD 300/60 group. The number of sperm per cauda epididymis was reduced in TCDD groups at puberty and at adulthood. Daily sperm production was permanently decreased as was the sperm transit rate in the TCDD-exposed male rats, thus increasing the time required by the sperm to pass through the cauda epididymis. Moreover, the male rats of the TCDD groups showed an increased number of abnormal sperm when investigated at adulthood. Similarly, mounting and intromission latencies were significantly increased in the TCDD 25/5 and TCDD 300/60 groups. In the highest dose group, serum testosterone concentration was decreased at adulthood. Likewise, in this dose group permanent changes including pyknotic nuclei and the occurrence of cell debris in the lumen were revealed. The lowest adverse effect level and the no observed effect level can be estimated to be substantially lower than the estimated daily dose of the lowest dose which is 0.8 ng/kg body wt/day. Sperm parameters were more susceptible than the other end points investigated. However, the question as to whether such doses exposed throughout gestation and lactation induce subtle changes in humans remains to be determined.
When administered in overtly toxic doses to postweanling male rats, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) produces adverse effects on the reproductive system including a decrease in spermatogenesis. Because the male reproductive system may be particularly susceptible to toxic insult during the perinatal period, the effects of in utero and lactational TCDD exposure on its development were examined. Male rats born to dams given TCDD (0.064, 0.16, 0.40, or 1.0 micrograms/kg, po) or vehicle on Day 15 of gestation were evaluated at various stages of development; effects on spermatogenesis and male reproductive capability are reported herein. Testis, epididymis, and cauda epididymis weights were decreased in a dose-related fashion at 32, 49, 63, and 120 days of age, that is, when males were at the juvenile, pubertal, postpubertal, and mature stages of sexual development, respectively. When measured on Days 49, 63, and 120, daily sperm production by the testis was reduced at the highest maternal TCDD dose to 57-74% of the control rate. Cauda epididymal sperm reserves in 63- and 120-day-old males were decreased to as low as 25 and 44%, respectively, of control values, although the motility and morphology of these sperm appeared to be unaffected. The magnitude of the effects described above tended to lessen with time; nevertheless, the decreases in epididymis and cauda epididymis weights, daily sperm production, and cauda epididymal sperm number were statistically significant at the lowest maternal dose tested (0.064 micrograms TCDD/kg) on Day 120 and at most earlier times. To determine if in utero and lactational TCDD exposure also affects male reproductive capability, rats were mated at approximately 70 and 120 days of age with control females. Little if any effect on fertility was seen, and the survival and growth of offspring was unaffected. These results are not inconsistent with the pronounced reductions in daily sperm production and cauda epididymal sperm reserves caused by perinatal TCDD exposure since rats produce and ejaculate far more sperm than are required for normal fertility. The TCDD-induced reduction in spermatogenesis cannot be accounted for by concurrent effects on plasma follicle-stimulating hormone or androgen concentrations or by undernutrition. To investigate the nature of the spermatogenic lesion, leptotene spermatocyte to Sertoli cell ratios were determined.(ABSTRACT TRUNCATED AT 400 WORDS)
Male rats exposed in utero to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) display reduced fertility as a consequence of the direct action of TCDD on the epididymides, as well as delayed puberty and altered reproductive organ weights. The current study provides dose-response data for the reproductive effects of TCDD, administered during pregnancy, with an emphasis on the effects of TCDD on testicular, epididymal, and ejaculated sperm numbers. Long Evans Hooded rats were dosed by gavage with 0, 0.05, 0.20, or 0.80 microg TCDD/kg on Day 15 of gestation. After birth, growth, viability, and developmental landmarks were monitored in both male and female offspring. Shortly after puberty (49 and 63 days of age) and at 15 months of age, male offspring were necropsied. Growth and viability of the pups were reduced only at 0.80 microg TCDD/kg, eye opening was accelerated (all dosage groups), and puberty was delayed (at 0.20 and 0.80 microg TCDD/kg). Treated progeny displayed transient reductions in ventral prostate and seminal vesicle weights, while epididymal sperm reserves and glans penis size were permanently reduced. Ejaculated sperm numbers were reduced (45% in the 0.8 and by 25% in the 0.05 and 0.2 microg TCDD/kg dosage groups) to a greater degree than were cauda or caput/corpus epididymal or testicular (unaffected) sperm numbers. In conclusion, administration of TCDD on Day 15 of pregnancy at 0.05 microg/kg altered eye opening and reduced ejaculated sperm counts, while higher dosage levels also delayed puberty and permanently reduced cauda epididymal sperm reserves.
Effects of Persistent and Bioactive Organic Pollutants on Human Health Endocrine disruptors: from endocrine to metabolic disruption
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Opinion of the SCF on the risk assessment of dioxins and dioxin-like PCBs in food. Up-date based on new scientific information
EC, 2001. Opinion of the SCF on the risk assessment of dioxins and dioxin-like PCBs in
food. Up-date based on new scientific information.
Effects of Persistent and Bioactive Organic Pollutants on Human Health
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Qualitative screening of undesirable compounds from feeds to fish by liquid chromatography coupled to mass spectrometry
- J Nacher-Mestre
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- F Hernandez
Nacher-Mestre, J., Ibanez, M., Serrano, R., Perez-Sanchez, J., Hernandez, F., 2013. Qualitative screening of undesirable compounds from feeds to fish by liquid chromatography coupled to mass spectrometry. J. Agric. Food Chem. 61, 2077-2087.