Monitoring of DDT, PCBs, and other organochlorine compounds in marine organisms from the North Aegean sea

Dichlorvos exposure results in large scale disruption of energy metabolism in the liver of the zebrafish, Danio rerio

Background

Exposure to dichlorvos (DDVP), an organophosphorus pesticide, is known to result in neurotoxicity as well as other metabolic perturbations. However, the molecular causes of DDVP toxicity are poorly understood, especially in cells other than neurons and muscle cells. To obtain a better understanding of the process of non-neuronal DDVP toxicity, we exposed zebrafish to different concentrations of DDVP, and investigated the resulting changes in liver histology and gene transcription.

Results

Functional enrichment analysis of genes affected by DDVP exposure identified a number of processes involved in energy utilization and stress response in the liver. The abundance of transcripts for proteins involved in glucose metabolism was profoundly affected, suggesting that carbon flux might be diverted toward the pentose phosphate pathway to compensate for an elevated demand for energy and reducing equivalents for detoxification. Strikingly, many transcripts for molecules involved in β-oxidation and fatty acid synthesis were down-regulated. We found increases in message levels for molecules involved in reactive oxygen species responses as well as ubiquitination, proteasomal degradation, and autophagy.

To ensure that the effects of DDVP on energy metabolism were not simply a consequence of poor feeding because of neuromuscular impairment, we fasted fish for 29 or 50 h and analyzed liver gene expression in them. The patterns of gene expression for energy metabolism in fasted and DDVP-exposed fish were markedly different.

Conclusion

We observed coordinated changes in the expression of a large number of genes involved in energy metabolism and responses to oxidative stress. These results argue that an appreciable part of the effect of DDVP is on energy metabolism and is regulated at the message level. Although we observed some evidence of neuromuscular impairment in exposed fish that may have resulted in reduced feeding, the alterations in gene expression in exposed fish cannot readily be explained by nutrient deprivation.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1941-2) contains supplementary material, which is available to authorized users.

Effects of persistent organic pollutants on the thyroid function of the European sea bass (Dicentrarchus labrax) from the Aegean sea, is it an endocrine disruption?

We evaluated the alterations of organochlorinated compounds such as polychlorobiphenyls (PCB), dichloro-diphenyl-dichloroethylene (DDE) and dichloro-diphenyl-trichloroethane (DDT) on the thyroid in wild and cultured sea bass (Dicentrarchus labrax) at environmental concentrations. These compounds influence the endocrine system of many fish species and are qualified as endocrine disruptors. The thyroid seems to be a target organ. Two alteration endpoints: the thyroid histology and the muscular thyroid hormone concentrations, were used simultaneously. High concentrations in PCBs and DDT were detected in muscles, supporting the idea that the Mediterranean fauna could be more polluted than the Atlantic fauna. The high abundance of DDE indicates a progressive degradation of remnant DDT load and the absence of new inputs in this area. Aquaculture sea bass shows a significant higher amount of pollutants on fresh weight basis (especially PCBs) in their muscles compared to the wild sea bass. Those differences may be related mainly to the contaminations of diet. Thyroid parameters vary between wild and aquaculture sea bass, wild sea bass were characterized by higher follicle diameters, epithelial cell heights and muscular T(4) concentrations. A significant relationship between persistent organic pollutants (muscular PCBs and DDT concentration) and the different thyroid parameters (diameters of follicles, epithelial cell heights and muscular T(4) levels) could be observed, which support the hypothesis that these compounds have an adverse impact on thyroid morphometry and function.

Organochlorine pesticide residues in human breast milk from southwest Greece: associations with weekly food consumption patterns of mothers

Breast milk samples were collected from 112 mothers who resided in southwest Greece during the years 1995-1997. The following chemicals, which were present in some of the milk samples, were quantified by gas chromatography: residues of lindane (i.e., alpha-hexachlorocyclohexane [BHC], beta-BHC, gamma-BHC), delta-BHC, 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p-DDE), 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane (p,p'-DDD, and 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (p,p'-DDT). With the assistance of a qualified dietitian, the mothers also completed a 7-d food-frequency questionnaire and provided additional personal information (e.g., educational level, profession, previous or present residence, use of pesticides, treatment of dermal scabies). Concentrations of gamma-BHC (i.e., lindane) were present in 57.1% of the samples (mean concentration = 0.58 microg/l [whole milk], range = nondetectable to 10.86 microg/l). Concentrations of alpha-BHC, beta-BHC, delta-BHC, p,p'-DDD, and p,p'-DDT were detected in 16%, 39.3%, 11.6%, 41%, and 55.3% of the samples, respectively. Moreover, p,p'-DDE, which was detected in all samples, ranged from 0.33 to 278 microg/l. Typically, the amounts of gamma-BHC and sigma-DDTs in breast milk were below the established acceptable daily intake value. Nonetheless, 3 of the 112 samples contained concentrations of sigma-DDT derivatives that exceeded the acceptable daily intake value established by the World Health Organisation in 1987. Concentrations of insecticides in breast milk were affected by dietary habits. Some women who consumed 7 (or more) portions of fresh vegetables per week had gamma-BHC concentrations in whole milk that exceeded 0.15 microg/l (odds ratio = 1.23 [95% confidence interval = 1.05, 1.44]; p = .006). The concentrations of DDT derivatives were associated with the portions of fish, chicken, fruits, milk, and potatoes consumed each week.

Analysis of toxic wastes in tissues from aquatic species. Applications of matrix solid-phase dispersion

One of the difficult tasks in studying toxic wastes in the environment is the process involved in their extraction from biological matrices. This review addresses the regulatory aspects which mandate subsequent analyses in aquatic species and the studies which have addressed these problems from a variety of analytical perspectives. In this regard, the tissue extraction process known as matrix solid-phase dispersion is also reviewed and data are presented indicating that it may provide a generic process for the extraction and subsequent analysis of pesticides, polynuclear aromatic hydrocarbons and polychlorinated biphenyls.

Polychlorinated biphenyls in fresh and canned fish from the Central Adriatic

By using the GLC method, levels of polychlorinated biphenyls (PCBs) were determined in fresh and canned fish during the 1984-88 period. Forty-six samples of fish caught in the Central Adriatic's littoral, 11 of which in a control, non-industrialized area, and 35 in an urbanized area strongly affected by industry, were collected. Also, 101 samples of canned fish were tested for PCBs. The average PCB values were 0.059 mg kg-1 and 0.287 mg kg-1 in control and polluted areas, respectively; the mean value in canned fish was 0.194 mg kg-1. Although the levels of PCBs in control and industrialized areas were found to differ, the difference was not significant statistically.

Polychlorinated biphenyls (PCBs) in the marine environment, particularly in the Mediterranean

Polychlorinated biphenyls (PCBs) possess a low water solubility, a high n-octanol/water partition coefficient, and a high persistence, particularly those which are highly chlorinated. Because of these properties they are bioaccumulated in many organisms in the environment. PCBs are still manufactured industrially and used in the Mediterranean countries (e.g., Italy, Spain, and France). Production figures for these countries and for the FRG, the United Kingdom, and the United States between 1973 and 1979 are given. The concentrations of PCBs in marine air, water, sediments, microplankton , algae, mussels, fish, and other marine organisms including seabirds from the Mediterranean area are reviewed and compared with PCB concentrations in marine samples from non-Mediterranean regions. Levels of PCBs in seawater are highest in the western and central Mediterranean. The data for mussels and fish give a clear indication that the PCB levels are higher in the Northwest and the Tyrrhenian Sea than in the eastern Mediterranean. The FDA in June 1979 set 2 mg/kg as the temporary maximum concentration for PCBs in fish and shellfish. The PCB residues in some fish from the northwestern Mediterranean and Tyrrhenian Sea and in some mussels from the Adriatic Sea are higher than this limit. The amount of PCBs ingested via food by the Mediterranean population is unknown.

Accumulation of a commercial polychlorinated biphenyl mixture (Aroclor 1016) in adult rhesus monkeys and their nursing infants

Female rhesus monkeys (24) were divided into 3 groups and fed diets calculated to contain 1.0, 0.25 or 0 parts per million (ppm) of a commercial mixture of polychlorinated biphenyls (PCBs), Aroclor 1016. The animals consumed a calculated total of 18.1 +/- 3.1, 4.5 +/- 0.6 and 0 mg Aroclor 1016/kg of body weight over the 87 +/- 9 week experimental period. All animals were bred, conceived and experienced uncomplicated pregnancies. The birth weights of the infants born to females receiving the 1.0 ppm PCB diets were significantly less than those of the control infants. There was a positive relationship between the levels of Aroclor 1016 in the tissues and the dose administered in the diets. Aroclor 1016 content of infant tissues was consistent with maternal adipose tissue PCB levels. The content of Aroclor 1016 in the milk fat of the animals more closely approximated that in the individual's adipose tissue than in the serum. At weaning, the mesenteric fat of the experimental infants contained concentrations of Aroclor 1016 which were 4-7 times that found in the mothers. Analyses of the tissues and fluids of the experimental animals demonstrated accumulation of PCB isomerides. The number of isomerides present and the ratio of those detected differed between adult and infants as well as between milk and serum. After weaning, the pattern of Aroclor 1016 isomerides present in the infants' adipose was similar to that observed at weaning although the concentrations had decreased.