Manuel Zumbado

Complex organochlorine pesticide mixtures as determinant factor for breast cancer risk: a population-based case-control study in the Canary Islands (Spain).

BackgroundAll the relevant risk factors contributing to breast cancer etiology are not fully known. Exposure to organochlorine pesticides has been linked to an increased incidence of the disease, although not all data have been consistent. Most published studies evaluated the exposure to organochlorines individually, ignoring the potential effects exerted by the mixtures of chemicals.MethodsThis population-based study was designed to evaluate the profile of mixtures of organochlorines detected in 103 healthy women and 121 women diagnosed with breast cancer from Gran Canaria Island, and the relation between the exposure to these compounds and breast cancer risk.ResultsThe most prevalent mixture of organochlorines among healthy women was the combination of lindane and endrin, and this mixture was not detected in any affected women. Breast cancer patients presented more frequently a combination of aldrin, dichlorodiphenyldichloroethylene (DDE) and dichlorodiphenyldichloroethane (DDD), and this mixture was not found in any healthy woman. After adjusting for covariables, the risk of breast cancer was moderately associated with DDD (OR = 1.008, confidence interval 95% 1.001-1.015, p = 0.024).ConclusionsThis study indicates that healthy women show a very different profile of organochlorine pesticide mixtures than breast cancer patients, suggesting that organochlorine pesticide mixtures could play a relevant role in breast cancer risk.

Ciguatera fish poisoning on the West Africa Coast: an emerging risk in the Canary Islands (Spain)

Ciguatera fish poisoning (CFP) is endemic in certain tropical and subtropical regions of the world. CFP had not been described on the West Africa Coast until a 2004 outbreak in the Canary Islands. In 2008-2009, two additional outbreaks of ciguatera occurred. Individuals afflicted had consumed lesser amberjack (Seriola rivoliana) captured from nearby waters. Caribbean ciguatoxin-1 (C-CTX-1) was confirmed in fish samples by LC-MS/MS. Ciguatoxic fish in this region may pose a new health risk for the seafood consumer.

Evaluation of acute and chronic hepatotoxic effects exerted by anabolic-androgenic steroid stanozolol in adult male rats.

Abstract Stanozolol (ST) is a 17α-alkyl anabolic-androgenic steroid (17α-AAS) often misused by athletes and bodybuilders. The use of anabolic-steroids by sportsmen and teenagers has increased dramatically, thus raising the question about their hepatotoxicity, specially those such as ST which are orally administered. Previously, we have reported diverse in vivo effects exerted by this steroid and published the existence of a highly specific ST-binding site in male rat liver microsomes. The existence of this binding site, the reported hepatic effects exerted in humans, and the very limited information about its potential hepatotoxicity led us to treat adult male rats acutely and chronically with ST and study different parameters that could indicate liver damage: serum levels of transaminases, concentration of monooxygenase enzymes in liver, liver membrane lipid peroxidation products, liver histopathology, and cell cycle/ploidy status of liver cells. In our study, no changes in serum transaminases or lipid peroxidation levels were obtained. However, acute stanozolol treatment significantly decreased the levels of cytochrome P450 (Cyt. P450) and cytochrome b5 (Cyt. b5) during the first 48 h of treatment, while subsequently, at 72 and 96 h, these microsomal enzymes underwent a significant increase in their levels. In sharp contrast with this response to acute treatment, the content of these two enzymes during chronic treatment showed an important decrease. Interestingly, acutely and chronically ST-treated livers showed slight to moderate inflammatory or degenerative lesions in centrilobular hepatocytes. Flow cytometric analysis demonstrated that both acute and chronic ST treatment were capable of increasing the percentage of S-phase fraction (%SPF) of liver cells. These findings taken together clearly show that this steroid is capable of altering the liver capacity for metabolizing xenobiotics and indicate that high doses of ST could exert a proliferative effect on liver cells. Such data should be considered in risk evaluations for this compound.

Determinants of organochlorine levels detectable in the amniotic fluid of women from Tenerife Island (Canary Islands, Spain).

Organochlorines (OCs) tend to accumulate in human tissues and can be measured in amniotic fluid (AF). The detection of OCs in AF samples reflects intrauterine exposure of human beings to these persistent organic pollutants. The present study was performed to evaluate the level of contamination of AF by OCs in 100 pregnant women from Tenerife Island (Canary Islands, Spain). Gas chromatography/mass spectrometry (GC/MS) was used to identify and quantify the analytes, including 7 polychlorobiphenyl (PCB) congeners and 18 OC pesticides and metabolites. The majority of the AF samples (67%) showed some detectable OC-residue, hexachlorobenzene (HCB) being the most frequently detected compound (66% of the samples) and at the highest concentration (median 0.023 ng/ml). Lindane was also detected in 28% of the samples. Inverse associations were found between previous lactation and hexachlorocyclohexane isomers (HCH) and cyclodienes in the group of younger women (p = 0.037 and p = 0.027, respectively). Unexpectedly, serum values of HCB (r = -0.414; p = 0.04), gamma-HCH (r = -0.294; p = 0.035), and SigmaOCs (r = -0.350; p = 0.014) were negatively related to age. Even more, women with detectable levels of HCH isomers were younger (33.9 +/- 4.9 years) than women with undetectable levels of them (36.1 +/- 4.9 years; p = 0.035). We conclude that approximately one in two fetuses in the Canary Islands is exposed to OCs in utero, and that, therefore, the exposure of young women from these Islands to some HCH isomers persists nowadays. Because prenatal exposure to these chemicals may be a causative factor in adverse health trends, further studies are required to enhance preventive measures.

Multi-residue method for the determination of 57 Persistent Organic Pollutants in human milk and colostrum using a QuEChERS-based extraction procedure

Human breast milk represents the best choice for the nutrition of infants. However, in addition to containing beneficial nutrients and antibodies, it can also be considered the best indicator of infant exposure to contaminants. We developed a multi-residue method using a modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) procedure and capillary gas chromatography–triple quadrupole mass spectrometry for the determination of 57 persistent organic pollutants, including 23 organochlorine pesticides, 18 polychlorinated biphenyl (PCB) congeners, and 16 polycyclic aromatic hydrocarbons in human milk and colostrum samples. We have used primary secondary amine in the clean-up step as it gave a more efficient separation of the analytes from fat and superior removal of the co-extracted substances compared with gel permeation chromatography. No significant matrix effect was observed for the tested pollutants, and therefore matrix-matched calibration was not necessary. The average recoveries from spiked samples were in the range of 74.8–113.0 %. The precision was satisfactory, with relative standard deviations below 16 %, while values of 0.1–0.4 μg L−1 were established as the limit of quantification for all the target analytes (0.05 and 100 μg L−1). The method was successfully applied to the analysis of 18 human colostrum and 23 mature milk samples. All the samples tested were positive for at least nine different residues, with some samples containing up to 24 contaminants. Remarkably, the contaminants hexachlorobenzene, p,p’-DDE, PCB 138, PCB 180, phenanthrene, fluoranthene, and pyrene were present in 100 % of the colostrum and mature milk samples analyzed.

Monitoring organic and inorganic pollutants in juvenile live sea turtles: results from a study of Chelonia mydas and Eretmochelys imbricata in Cape Verde.

Despite the current environmental concern regarding the risk posed by contamination in marine ecosystems, the concentrations of pollutants in sea turtles have not been thoroughly elucidated. In the current study, we determined the concentrations of 18 organochlorine pesticides (OCPs), 18 polychlorinated biphenyls (PCBs), 16 polycyclic aromatic hydrocarbons (PAHs) and 11 inorganic elements (Cu, Mn, Pb, Zn, Cd, Ni, Cr, As, Al, Hg and Se) for the first time in two sea turtle species (Chelonia mydas and Eretmochelys imbricata). Only five of the 18 analyzed OCPs were detected in both species. The average total OCP concentration was higher in green turtles than in hawksbills (0.33 ng/ml versus 0.20 ng/ml). Higher concentrations of individual congeners and total PCBs were also detected in green turtles than in hawksbills (∑PCBs=0.73ng/ml versus 0.19 ng/ml), and different PCB contamination profiles were observed in these two species. Concerning PAHs, we also observed a different contamination profile and higher levels of contamination in green turtles (∑PAHs=12.06 ng/ml versus 2.95 ng/ml). Di- and tri-cyclic PAHs were predominant in both populations, suggesting a petrogenic origin, rather than urban sources of PAHs. Additionally, all of the samples exhibited detectable levels of the 11 inorganic elements. In this case, we also observed relevant differences between both species. Thus, Zn was the most abundant inorganic element in hawksbills (an essential inorganic element), whereas Ni, a well-known toxicant, was the most abundant inorganic element in green turtles. The presence of contaminants is greater in green turtles relative to hawksbill turtles, suggesting a greater exposure to hazardous chemical contaminants for green turtles. These results provide baseline data for these species that can serve for future monitoring purposes outlined in the EUs Marine Strategy Framework Directive.

Assessment of the exposure to organochlorine pesticides, PCBs and PAHs in six species of predatory birds of the Canary Islands, Spain.

In the present study, we investigated the concentrations and distributions of 57 anthropogenic pollutants, including 23 organochlorine pesticides (OCs), 18 polychlorinated biphenyls (PCBs) and 16 polycyclic aromatic hydrocarbons (PAHs) in liver samples from 102 birds of prey of six species that were found dead or that had died during their stay in the Wildlife Recovery Centers of the Canary Islands (Spain) between 2009 and 2012. The dual goal of this work was to determine the occurrence of these contaminants in these six species of birds of prey, and also whether they can be used as bioindicators for monitoring environmental pollution in the region. We found that Accipiter nisus, Falco pelegrinoides and Falco tinnunculus were the most contaminated species. The profiles of contamination among the species were extremely similar in the case of organochlorine contaminants, with DDT and its metabolites as the most abundant compounds. The contamination by DDT and its metabolites, as well as contamination by dieldrin, could be considered high in these animals, much higher than reports from other regions of the planet, which is in agreement with previous reports from our group regarding humans, food and other animals from this area. In contrast, the contamination by PCBs could be considered extremely low and was probably below the threshold of toxicity for these contaminants. The content of carcinogenic/mutagenic PAHs in these animals was clearly dependent on the feeding pattern of the species; however, the levels were also well below the values that were considered toxic in predictive models. This study represents the first report of contamination by PAHs in all these species and is also the first report of PCB levels in Barbary Falcons.

Comparative study of polycyclic aromatic hydrocarbons (PAHs) in plasma of Eastern Atlantic juvenile and adult nesting loggerhead sea turtles (Caretta caretta).

Polycyclic aromatic hydrocarbons (PAHs) were measured in plasma samples of 162 juvenile loggerhead sea turtles (Caretta caretta) from Canary Islands, and 205 adult nesting loggerheads from Cape Verde. All the 367 samples showed detectable values of some type of PAH. Phenanthrene was the PAH most frequently detected and at the highest concentration in both populations. Median concentrations of ∑PAHs in the plasma of loggerheads from the Canary Islands and Cape Verde were similar (5.5 and 4.6 ng/ml, respectively). Di- and tri-cyclic PAHs were predominant in both populations suggesting petrogenic origin rather than urban sources of PAHs. In the group of turtles from Canary Islands, there was evident an increasing level of contamination over the last few years. The present study represents the first data of contamination by PAHs in sea turtles from the studied areas.

Polychlorobiphenyls and organochlorine pesticides in conventional and organic brands of milk: Occurrence and dietary intake in the population of the Canary Islands (Spain)

The population of the Spanish archipelago of the Canary Islands has been studied in depth regarding its levels of contamination by organochlorine pesticides (OCs) and polychlorinated biphenyls (PCBs). Foodstuffs of animal origin, such as milk, are prominent contributors to the body burden of these contaminants. As this population presents one of the highest milk-intake in Spain and Europe, we evaluated the level of OCs and PCBs in 26 commercially available brands of milk (16 conventional and 10 organic brands) present in the market of these Islands, in order to estimate the relevance of milk as a source of these chemicals for the Canary population. Our findings showed that hexachlorobenzene, trans-chlordane, and PCB153 were present in almost all the samples with independence of the type of milk. For both types of milks, the concentration of OCs was very low, showing organic milks lower levels than conventional ones. As a consequence, the estimated daily intake for OCs was lower than the tolerable daily intake (TDI) established by International Agencies. The levels of PCBs in milk were also found to be very low, but, in this case, the situation was the opposite: there were higher levels of PCBs in organic than in conventional brands of milk. Unexpectedly, levels of dioxin-like PCBs (DL-PCBs) reached values higher than 25 pg WHO-TEQ g(-1) fat in percentile 75 for both types of milk indicating the existence of a number of brands of milk highly contaminated by these toxicants. Consequently, the population who consume the most contaminated milk brands could have estimated daily intakes well above the recommended TDI (2 pg WHO-TEQ kg(-1)b.w.d(-1)) established by European Union Authorities. These results are of concern if we consider the well known adverse health effects exerted by dioxin-like compounds.

Background levels of polychlorinated biphenyls in the population of the Canary Islands (Spain)

Polychlorinated biphenyls (PCBs) are persistent and toxic compounds that have been detected in human serum or tissues worldwide. The objective of our study was to determine serum PCB levels in a representative sample of the general population of the Spanish Archipelago of the Canary Islands (607 serum samples from subjects aged between 6 and 75 years) in order to establish the main causes of this contamination and to evaluate the potential risks posed by these chemicals on the population through the use of toxicity equivalence to dioxins (TEQs). PCB congeners (28, 52, 77, 81, 101, 105, 114, 118, 123, 126, 138, 153, 156, 157, 167, 169, 180, and 189) were measured by gas chromatography-mass spectrometry (GC/MS). Our results showed that PCB residues were found in 76% of serum samples analyzed, with the congeners 153 and 180 being the most frequently detected and having the highest median values (21.8 and 6.7 ng/g lipid, respectively). Serum levels of non-dioxin-like PCBs increased with age, body mass index (BMI), urban habitat, and smoking. The median concentration of the sum of PCBs considered as markers of environmental contamination by these chemicals (M-PCBs) was 46.4 ng/g lipid. Levels of the sum of dioxin-like PCBs (DL-PCBs) were 48.5 ng/g lipid in the 95th percentile, and were also positively associated with age. As a consequence, age seemed to be positively associated with TEQs levels, reaching values as high as 58.6 pg/g lipid in the serum samples from oldest people. Our results indicate that the inhabitants of the Canary Archipelago show levels of PCB contamination lower than other populations present on the Spanish mainland, as well as many populations from developed countries. Nevertheless, as these compounds may induce adverse health effects even at very low doses, our findings should be considered by local Public Health authorities in order to establish measures for diminishing the exposure of the population of these islands to PCBs.