Persistent organic pollutants (POPs) in antarctic fish: levels,patterns, changes

Organochlorine compounds were analysed in three fish species of different feeding types from the area of Elephant Island in the Antarctic. In 1996, hexachlorobenzene (HCB) (means: 15-20 ng/g lipid), p,p'-DDE (5-13 ng/g lipid) and mirex (1-7 ng/g lipid) predominated, while PCBs were minor components (PCB 153: 0.4-2 ng/g lipid). Concentration patterns were species-dependent: PCB 180, PCB 153, mirex, nonachlor III, trans-nonachlor and the toxaphene compound B8-1413 were highest in the bottom invertebrate feeder Gobionotothen gibberifrons and lowest in the krill feeder Champsocephalus gunnari. Levels of p,p'-DDE, PCB 138 and heptachloro-1'-methyl-1,2'-bipyrrole (Q1), a natural bioaccumulative product, were highest in the fish feeder Chaenocephalus aceratus, whereas HCB was present in about equal concentrations in all species. Most compounds were taken up preferentially via the benthic food chain, the chlorinated bipyrrole via the pelagic food chain and HCB from the water. In antarctic fish, biomagnification was generally more important than bioconcentration. Between 1987 and 1996, most persistent organic pollutant (POP) levels showed significant increases in the benthos feeder and the fish feeder, while they remained nearly constant or increased less in the krill feeder. Hence, the former species represent indicator species for changing POP levels in Antarctica. Ratios (1996/1987) of average concentrations in G. gibberifrons were: PCB 138 0.7, HCB 0.8, B8-1413 1.5, PCB 180 1.7, PCB 153 1.8, p,p'-DDE 2.0, nonachlor III 2.9, trans-nonachlor 3.3, mirex 6.7. By comparison with trends in the northern hemisphere it is concluded that global distribution of HCB is close to equilibrium. Changing levels of other POPs reflect global redistribution and increasing transfer to antarctic waters probably due to recent usage in the southern hemisphere and climate changes.     

PCB, DDT, arsenic, and heavy metal (Cd, Cu, Pb, and Zn) concentrations in chameleon (Chamaeleo chamaeleon) eggs from Southwest Spain

This work presents the concentrations of twenty PCB congeners, p,p'-DDT, and its two main metabolites, p,p'-DDE, p,p'-TDE, As, Cd, Cu, Pb, and Zn found in common chameleon eggs from nine different nests located in Southwest Spain. Of the heavy metals and arsenic, Zn and Cu exhibited the highest concentrations in egg contents (ranging from 10100 to 12950 and from 567 to 706 ng g(-1) wet weight basis [w.w.], respectively) and eggshells (ranging from 5605 to 13290 ng g(-1)w.w. for Zn and from 1487 to 4361 ng g(-1)w.w. for Cu). Total PCB concentrations in egg contents ranged from 32 to 52 ng g(-1)w.w. and were higher than total dichlorodiphenylethanes concentrations (ranging from 0.67 to 1.9 ng g(-1)w.w., calculated as the sum of p,p'-DDT plus p,p'-DDE and p,p'-TDE). Comparison of the data from the present study with the data from a study conducted in 1997 revealed a large decrease in Pb concentration and a twofold increase in PCB concentrations. Taking into account all the pollutants investigated, the contamination level found in common chameleon eggs from Southwest Spain was generally lower than has been reported in the literature for eggs of different reptile species. However, it should be borne in mind that most of the data found in the literature refer to highly polluted areas.     

Polychlorinated dibenzo-p-dioxins,dibenzofurans and polychlorinated biphenyls in polar bear,penguin and south polar skua

Concentrations of 2378-substituted polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (DFs) and non- and mono-ortho-substituted polychlorinated biphenyls (dioxin-like PCBs) were measured in livers of polar bears from the Alaskan Arctic and in eggs of Adelie penguin and south polar skua and weddell seal liver, fish and krill from Antarctica. This is one of the first reports to document the concentrations of PCDDs/DFs in polar bear livers from Alaska, and in penguin and skua eggs from Antarctica. Concentrations of total PCDD/DFs in livers of polar bears ranged from 8 to 66 (mean: 26) pg/g, on a lipid weight basis. Concentrations of total PCDD/DFs in Antarctic samples were in the increasing order on a lipid weight basis; weddell seal liver (8.9 pg/g) < fish (11-17 pg/g) < krill (27 pg/g) > penguin eggs (30 ng/g) > seal liver (57 ng/g) > fishes (6.2 ng/g) > krill (0.9 ng/g). Concentrations of 2378-tetrachlorodibenzo-p-dioxin equivalents (TEQs) calculated based on the WHO TEFs were higher in the eggs of polar skua (mean: 344: range: 220-650 pg/g, lipid wt.) from Antarctica than in polar bear livers from Alaska (mean: 120; range: 69-192 pg/g). In general, concentrations of PCDFs were greater than those of PCDDs in polar organisms. 23478-PeCDF is one of the dominant congener found in several samples. Concentrations of TEQs in polar bear livers and skua eggs were close to those that may cause adverse health effects. Dioxin-like PCBs, particularly, non-ortho coplanar PCBs were the major contributors to TEQ concentrations in penguin and skua eggs whereas mono-ortho PCBs accounted for a major portion of TEQs in polar bear livers.     

Differences in p,p'-DDE bioaccumulation from compost and soil by the plants Cucurbita pepo and Cucurbita maxima and the earthworms Eisenia fetida and Lumbricus terrestris

Two plant species, Cucurbita pepo and Cucurbita maxima, and two earthworm species, Eisenia fetida and Lumbricus terrestris, were exposed to soil and compost with equivalent p,p'-DDE contamination. Pollutant bioconcentration was equal in plant roots in both media, but translocation was higher in C. pepo. Bioaccumulation by E. fetida was approximately 6- and 3-fold higher than that by L. terrestris in the soil and compost, respectively. For all species, p,p'-DDE uptake was significantly greater from soil than from compost; 7- to 8-fold higher for plant roots and 3- to 7-fold higher for worms. Abiotic desorption from soil was approximately twice that from the compost. When all the data are normalized for organic-carbon content of the media, the contaminant is more tightly bound by soil than compost. Although the risk associated with p,p'-DDE is higher in soil than compost, important mechanistic differences exist in contaminant binding to organic carbon in the two media.     

Occurrence of organochlorine pesticides (OCPs) and their enantiomeric signatures, and concentrations of polybrominated diphenyl ethers (PBDEs) in the Adélie penguin food web, Antarctica

Concentrations and enantiomeric signatures of organochlorine pesticides were determined in Antarctic krill, emerald rockcod and Adélie penguin from the Ross Sea, Antarctica. HCB and DDTs were prevalent contaminants in penguin eggs. The highest concentrations of SigmaHCHs (1.35 +/- 0.72 ng/g) were found in the rockcod muscle, where gamma-HCH (1.23 +/- 0.67 ng/g) was the principal isomer. The ratio gamma-HCH/alpha-HCH was evaluated. Enantioselective gas chromatography was used for the evaluation of enantiomeric fractions (EFs) for alpha-HCH and oxychlordane. An increase of 14% in the (+)alpha-HCH enantiomer was found from krill through penguin, suggesting the enantioselective biotransformation increased proportionately with trophic level. Polybrominated diphenyl ethers (PBDEs) were measured and their concentrations were 5.6 +/- 1.12, 5.81 +/- 2.32, 4.57 +/- 0.17 and 3.06 +/- 3.27 ng/g lipids in krill, rockcod muscle, rockcod homogenate and penguin eggs, respectively. The detection of BDE28, BDE47, BDE99 and BDE100 in Antarctic organisms confirmed their global transport and distribution; the detection of lower brominated congeners suggested a potential long-range transport.     

Differential bioavailability of field-weathered p,p'-DDE to plants of the Cucurbita and Cucumis genera

Field experiments were conducted to assess the bioavailability of weathered p,p'-DDE in soil to plants in the Cucurbita (squash, pumpkin) and Cucumis (cucumber, melon) genera. As expected, significant variability exists in the uptake of p,p'-DDE between plants of different genera. Root:soil concentration factors, defined as the ratio of p,p'-DDE (ng/g, dry weight) in the roots to that in the soil, approach 1.8 for cucumbers/melons and 16 for squash/pumpkin. However, significant differences were also observed among varieties of squash and pumpkin, with greater than an order of magnitude variation in the root:soil concentration factors and up to two orders of magnitude difference in the absolute amount of contaminant present within the plant. Although root systems routinely contain the highest concentration of p,p'-DDE (ng/g), this compartment comprises less than 2% of the total plant biomass. In all varieties but one, more than 86% of the extracted pollutant was in the shoot system. For two of varieties of Cucurbita pepo, concentrations of p,p'-DDE in the stems reached 1.1-2.2 mg/g and estimations of percent contaminant extraction from the soil ranged from 0.40% to 2.4%. These values approach those observed in the phytoremediation of heavy metals by "hyperaccumulating" species and indicate the potential for a plant-based remediation approach to soils contaminated with persistent organic pollutants.     

Multi-species interactions impact the accumulation of weathered 2,2-bis (p-chlorophenyl)-1,1-dichloroethylene (p,p'-DDE) from soil

The impact of interactions between the earthworms Eisenia foetida and Lumbricus terrestris and the plants Cucurbita pepo and Cucurbita maxima on the uptake of weathered p,p'-DDE from soil was determined. Although some combinations of earthworm and plant species caused significant changes in the p,p'-DDE burden in both organisms, the effects were species specific. Contaminant bioconcentration in C. pepo was increased slightly by E. foetida and by 3-fold when the plant was grown with L. terrestris. E. foetida had no effect on the contaminant BCF by C. maxima, but L. terrestris caused a 2-fold reduction in p,p'-DDE uptake by the plant. Contaminant levels in E. foetida and L. terrestris were unaffected by C. pepo. When grown with C. maxima, the concentration of p,p'-DDE decreased by approximately 4-fold and 7-fold in E. foetida and L. terrestris, respectively. The data suggest that the prediction of contaminant bioavailability should consider interactions among species.     

Rapid decline of persistent organochlorine pollutants in serum among young Swedish males

To investigate a possible time trend in serum concentrations of persistent organochlorine pollutants (POPs), representative samples of the young (median age 18 years) Swedish male population were investigated in the years 2000 and 2004. Due to their low age, these men were assumed not to have reached steady state of body burdens of POPs, why their serum concentrations were considered to represent ongoing dietary exposure. Serum concentrations of 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153) and 1,1-dichloro-2,2-bis(4-chlorophenyl)-ethylene (p,p'-DDE), two biomarkers of exposure to POPs, were available for 274 and 223 men, respectively, in 2000 and for 200 men in 2004. The percentage of men with CB-153 or p,p'-DDE below the limit of detection (LOD) was significantly higher in 2004 than in 2000 (30% vs. none, p < 0.001 for CB-153 and 65% vs. 6%, p < 0.001 for p,p'-DDE). Moreover, the median serum concentration of CB-153 decreased from 66 ng g(-1) lipid to 19 ng g(-1), corresponding to a yearly decrease of about 26%. The analogous analysis was not done for p,p'-DDE since the median serum concentration in 2004 was below the LOD.     

Organochlorine pesticides and polychlorinated biphenyls in air and soil across Azerbaijan

Concentrations of selected organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) are reported in air and surface soil in an extensive spatial survey across Azerbaijan, a country bordering the Caspian Sea with a history of OCP production and extensive use. Polyurethane foam disc passive air samplers (PAS) were deployed during October-November 2008 with soil samples collected in July 2009. Levels of Σ(7)PCB in ambient air were generally low (mean of 0.046 ng m(-3), n?=?13) and comparable to concentrations reported in countries within Eastern Europe and similar to or lower than concentrations reported in urban air in the UK and other western countries. Surprisingly, PCB concentrations in rural/background soil fell below the method detection limits at most sites, although concentrations were 0.209 and 0.071 ng Σ(7)PCB g(-1) dry weight (dw) for two urban sites, again comparable to PCB levels measured at background sites in Europe. Levels of α-HCH, β-HCH, γ-HCH and p,p'-DDT/E were elevated in ambient air across Azerbaijan in comparison to PAS-derived concentrations reported elsewhere, with concentrations of α-HCH in air ranging from 0.085 to 2.699 ng m(-3) and p,p'-DDE, 0.037-2.290 ng m(-3). High concentrations of OCPs occurred at several of the urban sites and at sites in proximity to old pesticide storage facilities with concentrations in soil >0.1 μg g(-1) dw for p,p'-DDE and p,p'-DDT at several sites. The ratio of p,p'-DDT/p,p'-DDE was close to unity in the soil at these sites, but elsewhere, the ratio was <1, indicating a weathered DDT pattern, which was also reflected in the air at all sites. A fugacity approach revealed the strong likelihood of net soil-to-air transfer at the majority of sites for all OCPs. The calculated annual fluxes or loading to the atmosphere from a rural/agricultural area (representing land as vineyards and cotton cultivation) were estimated to be on the order of ≈10-100 kg year(-1) for the HCH isomers (including the β -isomer) and p,p'-DDE. The high levels of OCPs in soils, particularly in the vicinity of obsolete-pesticide storage facilities and at select urban sites are of concern and warrant regular monitoring activities and the development of containment or mitigation strategies.     

Polychlorinated-naphthalenes, -biphenyls, -dibenzo-p-dioxins, -dibenzofurans and p,p'-DDE in bluefin tuna,swordfish, cormorants and barn swallows from Italy

Concentrations of p,p'-DDE, polychlorinated biphenyl congeners (PCBs), polychlorinated-dibenzo-p-dioxins (PCDDs), -dibenzofurans (PCDFs) and -naphthalenes (PCNs) were measured in bluefin tuna, swordfish, common cormorants, and barn swallows collected from Italy. Average concentrations of PCBs in livers of tuna, swordfish, cormorant, and swallows were 930, 745, 1420 and 1230 ng PCBs g-1, w.w. respectively. p,p'-DDE was found in tuna, swordfish, cormorant, and swallow livers at mean concentrations of 82, 135, 166 and 95 ng DDE g-1, w.w. respectively. PCNs were found in all the samples analyzed, although at concentrations less than those reported for biota from the Baltic Sea. PCBs, particularly, non-ortho coplanar PCBs accounted for 80-90% of the total TEQs in tuna and swordfish. Relative contribution of PCDDs/DFs to TEQs was greater in cormorants and swallows compared to that in fishes. PCDD/DF congeners accounted for up to 80 and 45% of the total TEQs in cormorants and swallows, respectively.     

Comparison of atmosphere/aquatic environment concentration ratio of volatile chlorinated hydrocarbons between temperate regions and Antarctica

For the purpose of understanding the transport and deposition mechanisms and the air–water distribution of some volatile chlorinated hydrocarbons (VCHCs), their atmosphere/aquatic environment concentration ratio was evaluated. In addition, for the purpose of differentiating VCHC behaviour in a temperate climate from its behaviour in a polar climate, the atmosphere/aquatic environment concentration ratio evaluated in matrices from temperate zones was compared with the concentration ratio evaluated in Antarctic matrices.In order to perform air samplings also at rigid Antarctic temperatures, the sampling apparatus, consisting of a diaphragm pump and canisters, was suitably modified.Chloroform, 1,1,1-trichloroethane, tetrachloromethane, 1,1,2-trichloroethylene and tetrachloroethylene were measured in air, water and snow using specific techniques composed of a purpose-made cryofocusing-trap-injector (for air samples) and a modified purge-and-trap injector (for aqueous samples) coupled to a gas chromatograph with mass spectrometric detection operating in selected ion monitoring mode. The VCHCs were retrieved in all the investigated matrices, both Italian and Antarctic, with concentrations varying from tens to thousands of ng m⁻³ in air and from digits to hundreds of ng kg⁻¹ in water and snow.The atmosphere/aquatic environment concentration ratios were always found to be lower than 1. In particular, the Italian air/water concentration ratios were smaller than the Antarctic ones, by reason of the higher atmospheric photochemical activity in temperate zones. On the other hand, the Antarctic air/snow concentration ratios proved to be largely in favour of snow with respect to the Italian ratios, thus corroborating the hypothesis of a more efficient VCHC deposition mechanism and accumulation on Antarctic snow.     

Organochlorine residue levels in livers of birds of prey from Spain: inter-species comparison in relation with diet and migratory patterns

Livers from 130 specimens corresponding to 18 species of raptors from Spain were analysed for persistent organochlorine (OC) residues. In all species, p,p'-DDE was the most abundant individual OC compound detected, with geometric means ranging from 61 to 40,086 ng/g ww. The geometric mean for summation operator PCB ranged from 225 to 9184 ng/g ww. Migration to Africa, south of Sahara, where p,p'-DDT is still in use, was not associated with higher liver concentrations of its metabolite, p,p'-DDE. The presence of birds in the diet of the species was an important species-specific factor determining the mean liver concentrations of p,p'-DDE and summation operator PCB. The effect of the diet on OC concentrations in liver is explained by the lower metabolising capacity of OC compounds in birds, especially for p,p'-DDE.     

Organochlorine pesticides and metabolites in young leaves of Mangifera indica from sites near a point source in Coast region, Tanzania

Young leaves of Mangifera indica (mango tree) from nine sites were used as bioindicators of local atmospheric contamination by organochlorine pesticides and metabolites from a point source, an old storage site at Vikuge farm in Tanzania. Sample extracts were analysed by GC-ECD and GC-MS. The concentrations ranged 2.7-649 ng g(-1)p,p'-DDT, below detection limit (bdl)-290 ng g(-1) o,p'-DDT, 0.4-13 ng g(-1) p,p'-DDE, bdl to 4 ng g(-1) o,p'-DDE, 1-231 ng g(-1) p,p'-DDD and 0.5-55 ng g(-1) o,p'-DDD. The concentrations of other compounds were up to 3.9 ng g(-1) pentachloroanisole, 1.3 ng g(-1) alpha-HCH, 12 ng g(-1) beta-HCH and 2 ng g(-1) gamma-HCH, on fresh weight basis. The compounds p,p'-DDT, p,p'-DDE, p,p'DDD and o,p'-DDD were found in 100% of the samples, while pentachloroanisole, o,p'-DDT and o,p'-DDE were detected in 78%, 56% and 67% of the samples, respectively. The low DDE/DDT ratios (0.01-0.20) in all samples indicate recent input of significantly non-degraded DDT from the point source. The low alpha-/gamma-HCH ratios (<0.3-0.7) in most samples indicate recent input of lindane (99% gamma-HCH). The slightly high alpha-/gamma-HCH ratios in some samples might be due to photochemical or bacterial transformation of gamma-HCH to alpha-HCH, or could reflect input of technical HCH. The very strong positive correlations in the concentrations of p,p'-DDT, p,p'-DDE, p,p'-DDD, o,p'-DDT, o,p'-DDE and o,p'-DDD (r=0.91-0.98, n=18, p<0.01) indicate that they have a common source. The results suggest that young mango leaves are suitable bioindicators of recent inputs of organochlorine contaminants from a point source.     

Placental transfer of DDT in mother-infant pairs from Northern Thailand

The present study objective was to investigate ratios and correlation coefficients between dichlorodiphenyltrichloroethane (DDT) compounds in cord and maternal sera of mother-infant pairs from northern Thailand. The study site was located in Chiang Dao District of Chiang Mai Province which was an agricultural and former malaria endemic area. DDT compounds were analyzed in 88 cord and maternal serum samples using gas chromatography-electron capture detection (GC-ECD). p,p'-DDE (1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene) was the major component and detected in every cord and maternal serum samples with geometric means of 1,255 and 1,793 n g(-1) lipids, respectively. p,p'-DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane) was detected at 89.8 and 100% of cord and maternal serum samples, respectively. The second and third highest levels detected were p,p'-DDD (1,1-dichloro-2,2-bis(p-chlorophenyl)ethane) and p,p'-DDT, respectively. The ratios between cord and maternal sera for p,p'-DDE, p,p'-DDT, and p,p'-DDD that were less than 1 had high correlation coefficients (ratio = 0.70, r = 0.82 for p,p'-DDE, ratio = 0.62, r = 0.66 for p,p'-DDT, and ratio = 0.79, r = 0.78 for p,p'-DDD). The high correlation coefficients indicate that cord serum levels of DDT compounds could be accurately estimated from maternal serum levels. It can be concluded that cord serum levels of p,p'-DDE, p,p'-DDT, and p,p'-DDD were approximately 70%, 62%, and 79% of maternal serum levels, respectively. Furthermore, our findings can be applied in public health to monitor and evaluate risk among infants from high DDT exposure area.     

Ozone uptake to the polar snowpack at Summit,Greenland

The uptake of atmospheric ozone to the polar, year-round snowpack on glacial ice was studied at Summit, Greenland during three experiments in 2003, 2004, and 2005. Ozone was measured at up to three depths in the snowpack, on the surface, and above the surface at three heights on a tower along with supporting meteorological parameters. Ozone in interstitial air decreased with depth, albeit ozone gradients showed a high variation depending on environmental conditions of solar radiation and wind speed. Under low irradiance levels, up to 90% of ozone was preserved up to 1 m depth in the snowpack. Ozone depletion rates increased significantly with the seasonal and diurnal cycle of solar irradiance, resulting in only 10% of ozone remaining in the snowpack following solar noon during summertime. Faster snowpack air exchange from wind pumping resulted in smaller above-surface-to-within snowpack ozone gradients. These data indicate that the uptake of ozone to polar snowpack is strongly dependent on solar irradiance and wind pumping. Ozone deposition fluxes to the polar snowpack are consequently expected to follow incoming solar radiation levels and to exhibit diurnal and seasonal cycles. The Summit observations are in stark contrast to recent findings in the seasonal, midlatitude snowpack [Bocquet, F., Helmig, D., Oltmans, S.J., 2007. Ozone in the mid-latitude snowpack at Niwot Ridge, Colorado. Arctic, Antarctic and Alpine Research, in press], where mostly light-independent ozone behavior was observed. These contrasting results imply different ozone chemistry and snowpack–atmosphere gas exchange in the snow-covered polar, glacial conditions compared to the temperate, mid-latitude environment.     

Aging activity of DDE in dissimilar rice soils in a greenhouse experiment

A green-house study was conducted in late 2005 to investigate the aging behavior of p,p'-DDE in two types of soil, Hydragric Anthrosols (An) and Hydragric Acrisols (Ac), according to the World Reference Base (WRB) [FAO/ISRIC/ISSS. 1998. World reference base for soil resources. World soil resources reports, Rome. p. 87]. Paddy rice and dry rice were grown in submerged paddy soils and non-submerged upland soils, respectively. The concentration of extractable p,p'-DDE in fresh DDE-spiked soils was 746.2ngg(-1). During the first few weeks of the experiment, the extractability of p,p'-DDE became increasingly low as the aging period prolonged. However, certain amount of p,p'-DDE that had been captured by soil minerals and organic matter (OM) could be released and became extractable in the later period. The extractability of p,p'-DDE in submerged soils was significantly lower than that in non-submerged soil, because flooding could increase the binding of pollutants to soil particles. The plantation of both dry rice and paddy rice slowed down the aging process of p,p'-DDE. After one month's growth of rice, p,p'-DDE bound to soil particles was released and became extractable. The OM and silt content of An are higher than that of Ac, resulting in more bound residues and relative lower extractability of p,p'-DDE in An. In addition, the extractability of p,p'-DDE could be reduced by the addition of rice straw to soils.     

Persistent organochlorine residues in livers of six species of Ciconiiformes (aves) from Spain

Liver samples of 42 birds belonging to 6 species of Ciconiiformes (grey heron (n = 17), little egret (n = 12), cattle egret (n = 1), glossy ibis (n = 1), little bittern (n = 1), and white stork (n = 10)), collected from two different zones of Spain (Ebro Delta and Madrid) in 1992-1997, were analyzed for organochlorine pesticides and PCBs. SigmaPCBs (sum of concentrations of individual congeners), p,p'-DDE, HCB, gamma-HCH, and heptachlor epoxide were the most prevalent residues detected in all samples (occurrence > 95%). There were no statistically significant differences in organochlorine levels between grey herons and little egrets, while levels of SigmaPCBs, p,p'-DDE, HCB, gamma-HCH, and heptachlor were significantly lower for white storks. These results could be explained by the different habitat of these species, aquatic in the Ebro Delta (grey herons, little egrets) and dry in Madrid (white stork), and their diverse feeding habits.     

Metabolism of DDT in different tissues of young rats

The bioconcentration and distribution pattern of p,p'-DDT 1,1,1-1trichloro-2,2-bis(2-chlorophenyl-4-chlorophenyl)-ethane] and its main metabolites (p,p'-DDD [1,1-dichloro-2,2-bis (4-chlorophenyl) ethane] and p,p'-DDE [1,1-dichloro-2,2-bis (4-chlorophenyl) in adipose tissue, liver, brain, kidney, thymus, and testis were examined in young rats after 10 days of intraperitoneal injection of 50 and 100 mg of p,p'-DDT/kg of body weight. Analyses were performed by high-resolution gas chromatography. p,p'-DDT was found to be accumulated in a dose-dependent manner with the highest concentration in adipose tissue. However, in brain, the accumulation of pesticide was low and remained unchanged at the higher dose. This difference may relate to the protective role of the blood-brain barrier, which limits the access of the xenobiotic in the cerebral compartment, and to the differential tissue lipid composition. Although tissues concentration of p,p'-DDE and p,p'-DDD correlated positively to total p,p'-DDT levels, the active role in detoxification of pollutants may explain why p,p'-DDD is more abundant in liver than in the rest of organs. On the contrary, in brain, the concentration of p,p'-DDE is higher than that of p,p'-DDD, suggesting that the metabolism of the parent insecticide proceeds via more than one pathway.     

Effect of dietary fluoride derived from Antarctic krill (Euphausia superba) meal on growth of yellowtail (Seriola quinqueradiata)

Yellowtail (Seriola quinqueradiata) is the most important cultured marine fish in Japan. Dietary fish meal for yellowtail in aquaculture was replaced with 0.0%, 15.4% and 100.0% Antarctic krill meal (KM0, KM15, and KM100) and with 0.0%, 15.4%, and 100.0% low-fluoride krill meal (LFK0, LFK15 and LFK100). The fish was fed to duplicate fish groups for 92 d (KM trial) or 75 d (LFK trial), and fish growth was monitored.Dietary fluoride (F⁻) concentrations (mg kg⁻¹) were 110, 160, and 580 (KM0, KM15, and KM100, respectively) and 98, 120, and 190 (LFK0, LFK15, and LFK100, respectively). The growth during the experimental period, weight gain, feed intake, specific growth rate, and feed efficiency in fish fed the KM100 diet were markedly lower than the other experimental groups, which showed no marked differences in growth performance.After the experiment, dorsal muscle fluoride concentrations in each group were below the detectable limit (1 mg kg⁻¹), but vertebral bone fluoride concentrations increased with increasing proportion of KM to 655 (KM0), 870 (KM15), and 2150 (KM100) mg kg⁻¹. With increasing LFK in the feed, vertebral bone fluoride concentrations (mg kg⁻¹) increased slightly from 500 (LFK0) to 655 (LFK15), and 695 (LFK100). No histopathological changes were detected in the liver tissue in any experimental group.It has been reported that the fluoride bioavailability was reduced with increasing water hardness, however, the dietary fluoride derived from KM exoskeleton accumulates in vertebral bones of marine fish with growth inhibition, as has already been shown for freshwater fish. Vertebral bone fluoride concentrations in two krill-eating Antarctic marine fish in the wild were 33 000 mg kg⁻¹ (Champsocephalus gunnari) and 15 000 mg kg⁻¹ (Notothenia rossii), but they did not show any adverse effect of growth. Therefore, fish bone fluoride accumulation apparently depends on fish species rather than the salinity of the habitat. Consequently, krill exoskeleton must be removed during the processing of Antarctic krill if indeed these krill are to be used as fish feed. However, LFK can completely replace dietary fish meal without apparent adverse effects.     

Associations between CB-153 and p,p'-DDE and hormone levels in serum in middle-aged and elderly men

BACKGROUND: Animal and epidemiologic data indicate that exposure to persistent organochlorine pollutants (POPs) may disrupt the hypothalamus-pituitary-thyroid (HPT) and the hypothalamus-pituitary-gonadal (HPG) axes. We have assessed whether the POP-biomarkers 2,2'4,4',5,5'-hexachlorobiphenyl (CB-153) and 1,1-dichloro-2,2-bis(4-chlorophenyl)-ethene (p,p'-DDE) affect thyrotropin (TSH), thyroid hormones, gonadotropins or sex hormone concentrations in men. METHODS: Lipid adjusted serum concentrations of CB-153, and p,p'-DDE, were determined in 196 men (median age 59 years, range 48-82). Hormone analyses in serum were performed with immunoassays. The effect of CB-153 and p,p'-DDE (as continuous or categorized variables) were evaluated by linear regression models, adjusting for potential confounders. RESULTS: There was a significant positive association between p,p'-DDE and TSH. An increase of 100 ng/g lipid of p,p'-DDE corresponded to an increase of 0.03 mU/l (95% Confidence Interval (CI) 0.01, 0.05) in TSH level. The explanatory value (R(2)) of the multivariate model was only 7%. Moreover, there was a significant negative association between p,p'-DDE and estradiol. An increase of 100 ng/g lipid of p,p'-DDE corresponded to a decrease of 0.57 pmol/l (95% CI -1.0, -0.12) in estradiol level. The R(2)-value was only 4%. No associations were observed between any of the POP biomarkers and the other hormones. CONCLUSIONS: The positive association between p,p'-DDE and TSH and the negative association between p,p'-DDE and estradiol, among middle-aged and elderly men, were not accompanied by associations between the POP-markers and thyroxin, testosterone, and gonadotropins, respectively. The results gives some additional support for that POP exposure may affect HPT- and HPG-axes also in humans, but the overall epidemiological data are still not coherent enough to allow any firm conclusions.