Immunologic effects of perinatal exposure to dioxins, PCBs and organochlorine pesticides in Japanese infants

Effects of perinatal exposure to dioxins, PCBs and organochlorine pesticides on lymphocyte subsets were investigated in the peripheral blood from 101 Japanese infants with approximately 10 months of age. Perinatal exposure to these organochlorine compounds were estimated by their contamination levels in the breast milk of the mothers. Lymphocyte subsets such as CD16+, HLA-DR+, CD4+, CD4+8+, CD8+, CD3+ and CD20+ cells in peripheral venous blood were assessed in a subgroup of 92 infants. Greater exposures to HCE, chlordane and dioxins were significantly associated with the increase in the percentages of CD8+ and CD3+ T lymphocytes and CD4+/CD8+ T cell ratios, respectively. In addition, higher HCH exposure was also associated with a decrease in the percentage of HLA-DR+ T lymphocytes. Furthermore effects of dioxins, DDT and PCBs on the percentage of CD16+ T lymphocyte were more pronounced by the combined exposure of dioxins and PCBs or by the combined exposure of DDT and PCBs. Effects of HCE on the percentages of CD8+ T lymphocyte were also more pronounced by the combined exposure of HCE and chlordane. In conclusion, our study suggests that greater exposures to dioxins, PCBs and organochlorine pesticides determined in this study (except dieldrin) influence the immune system of Japanese infant, although the clinical significance of these changes is uncertain.     

Cross-country analysis of relationship between material input structures and consumption-based CO2 emissions

Environmental Economics and Policy Studies - This study focuses on the effects of changes in material and energy input structure on the consumption-based CO2 emissions. Previous studies...     

Validation of an automated data collection method for quantifying social networks in collective behaviours

The social network of preferences among group members can affect the distribution and consequences of collective behaviours. However, the behavioural contexts and taxa in which social network structure has been described are still limited because such studies require extensive data. Here, we highlight the use of an automated passive integrated transponder (PIT)-tag monitoring system for social network analyses and do so in a novel context—nestling provisioning in an avian cooperative breeder, for which direct observation of social behaviours is difficult. First, we used observers and cameras to arrive at a suitable metric of nest visit synchrony in the PIT-tag data. Second, we validated the use of this metric for social network analyses using internal nest video cameras. Third, we used hierarchical regression models with ‘sociality’ parameter to investigate structure of networks collected from multiple groups. Use of PIT tags led to nest visitation duration and frequency being obtained with a high degree of accuracy for all group members, except for the breeding female for whom accurate estimations required the use of a video camera due to her high variability in visitation time. The PIT-tag dataset uncovered significant variability in social network structure. Our results highlight the importance of combining complementary observation methods when conducting social network analyses of wild animals. Our methods can also be generalised to multiple contexts in social systems wherever repeated encounters with other individuals in closed space have ecological implications.     

Recent survey and effects of cooking processes on levels of PCDDs,PCDFs and Co-PCBs in leafy vegetables in Japan

We report here the latest levels of polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans (PCDD/Fs) and coplanar polychlorinated biphenyls (Co-PCBs) in leafy vegetables in Japan as well as the effect of cooking processes on the reduction of these contaminants. Three kinds of leafy vegetables (“komatsuna”, lettuce and spinach) from seven districts in Japan in 1998 were analyzed for the 2,3,7,8-chlorine substituted PCDD/Fs and three non-ortho-PCBs (#77, 126 and 169). The mean total TEQ levels (using the WHO-TEFs) in the komatsuna, lettuce and spinach were 0.094, 0.025 and 0.196 pg/g fresh weight, respectively. The TEQ levels are dominated by 2,3,7,8-TCDD, 1,2,3,7,8-PeCDD, 2,3,4,7,8-PeCDF and 3,3^′,4,4^′,5-PeCB in many of the samples. For one of these isomers, the 2,3,4,7,8-PeCDF TEQ levels showed good correlation with the total TEQ levels in the samples (r=0.957). This suggests that 2,3,4,7,8-PeCDF may be an indicator for dioxin contamination in the analysis of the leafy vegetables. Also, the effects of two cooking processes (washing and washing followed by boiling) on the dioxin levels in two types of spinach samples were investigated. On average, in both samples, the total concentrations of the PCDDs, PCDFs and Co-PCB were reduced to about 38%, 73% and 88% of the initial concentrations by washing, and to 21%, 35% and 61% of the initial concentrations by washing followed by boiling. The total TEQ levels were reduced to about 30% of the initial TEQ levels by washing followed by boiling. Significant reductions in the TEQ levels were observed in the cooked samples. Thus, the cooking processes may reduce the risk of dioxin intake from the leafy vegetables.     

Behavior of atrazine in soils of tropical zone

Abstract

Movement and degradation of ¹⁴C‐atrazine (2‐chloro 4‐(ethylamino)‐6‐(isopropylamino)‐s‐triazine, was studied in undisturbed soil columns (0.50m length × 0.10m diameter) of Gley Humic and Deep Red Latosol from a maize crop region of Sao Paulo state, Brazil. Atrazine residues were largely confined to the 0–20cm layers over a 12 month period Atrazine degraded to the dealkylated metabolites deisopropylatrazine and deethylatrazine, but the major metabolite was hydroxyatrazine, mainly in the Gley Humic soil. Activity detected in the leachate was equivalent to an atrazine concentration of 0.08 to 0.11μg/1.

The persistence of ¹⁴C‐atrazine in a maize‐bean crop rotation was evaluated in lysimeters, using Gley Humic and Deep Red Latosol soils. Uptake of the radiocarbon by maize plants after 14‐days growth was equivalent to a herbicide concentration of 3.9μg/g fresh tissue and was similar in both soils. High atrazine degradation to hydroxyatrazine was detected by tic of maize extracts. After maize harvest, when beans were sown the Gley Humic soil contained an atrazine concentration of 0.29 μg/g soil and the Deep Red Latosol, 0.13 μg/g soil in the 0–30 cm layer. Activity detected in bean plants corresponded to a herbicide concentration of 0.26 (Gley Humic soil) and 0.32μg/g fresh tissue (Deep Red Latossol) after 14 days growth and 0.43 (Gley Humic soil) and 0.50 μg/g fresh tissue (Deep Red Latossol) after 97 days growth. Traces of activity equivalent to 0.06 and 0.02μg/g fresh tissue were detected in bean seeds at harvest. Non‐extractable (bound) residues in the soils at 235 days accounted for 66.6 to 75% (Gley Humic soil and Deep Red Latossol) of the total residual activity.     

Heart rate changes reveal that little blue penguin chicks (Eudyptula minor) can use vocal signatures to discriminate familiar from unfamiliar chicks

Researchers investigating social recognition typically measure only behavioural responses during discrimination tests - physiological changes have been largely ignored. We examined whether little blue penguin chicks (Eudyptula minor) could distinguish siblings from other chicks using auditory cues, by measuring behavioural and heart rate changes during playback experiments. Chicks were exposed to five treatments: the begging calls of siblings, neighbouring chicks and unfamiliar chicks, and two controls (heterospecific begging calls and music). We also determined if chicks developed distinctive begging calls, by using F-ratios to quantify inter- versus intra-individual variability in a range of acoustic parameters, and applying a discriminant-function analysis. Inter-individual variation was greater for pitch than for temporal or amplitude parameters, suggesting that call pitch may be important for individual recognition. The discriminant-function analysis showed each chick's calls were distinctive and could act as a vocal signature. Treatments did not instigate different behavioural responses. However, chick heart rates during playback of sibling calls were significantly higher than those recorded during stranger, but not neighbour, playback. A simple recognition system based on familiarity may allow this plesiomorphic and loosely colonial penguin to gain at least some of the benefits associated with more advanced sibling recognition systems (some highly colonial seabirds discriminate siblings from neighbouring chicks). Heart rate could be a useful measure of social recognition abilities, particularly in species where changes in behaviour are not always evident or are difficult to observe.     

Soil heterogeneity effects on acid flushing of lead-contaminated soil

A compact model for evaluation of acid flushing of heavy-metal-contaminated soil in a small-scale on-site treatment plant is proposed. The model assumes that the soil was re-packed in a container after excavation resulting in a soil structure with heterogeneous and random physical and chemical properties. To evaluate the effects of heterogeneity on the efficiency of contaminant removal by acid flushing, a numerical analysis of lead transport in the heterogeneous soil medium was performed. The model examines cation exchange and surface complexation reactions involving three cations (Ca, Pb, and H) and one anion (Cl) in both dissolved and exchangeable forms, two Pb surface complexes (SOPbCl and SOPbOH), and one Cl surface complex (SOH₂Cl). The transport of these species during flushing with acid in a synthetically generated two-dimensional heterogeneous soil was simulated in the model. Results indicated that the flushing fluid preferentially followed pathways with large permeability. The heterogeneous cation exchange capacity (CEC) distribution and surface complexation sites had a significant effect on the transport of dissolved species. Because the CEC was set to a relatively low value, Pb was adsorbed mainly as surface complexes (SOPbCl and SOPbOH). Simulation results suggest that blocks of low hydraulic conductivity located in the upper part of the model domain greatly impede solute transport. Ponding conditions did not significantly affect the efficiency of decontamination. The model and its results are useful in the design of small-scale treatment plants for acid flushing.     

Residual congener pattern of dioxins in human breast milk in southern Vietnam

This study evaluated residual congener patterns of dioxin/furan (=PCDD/DF) related to tactical herbicides aerially sprayed over the regions of southern Vietnam through Operation Ranch Hand. The study focused on Cam Chinh (CC) commune, Quang Tri province (an area sprayed with tactical herbicides), and the Cam Phuc (CP) commune, Ha Tinh province (a non-sprayed area). Breast milk samples for analysis were collected in September 2002 and July 2003 from lactating primiparous and multiparous mothers born after the war (<31 years old). We found the levels of each congener in the CC commune were higher than in the CP commune, and determined specificity in the PCDD/DF congener pattern in CC commune samples by cluster analysis. The congener pattern is characterized by higher (the hexa-, the hepta-, and the octa-) chlorinated PCDD/DFs; this appears to be the same profile as that presented by pentachlorophenol (PCP), rather than 2,4,5-trichlorophenoxy acid (2,4,5-T) contaminated with 2,3,7,8-TCDD. A GC/MS study in the 1970s detected the chlorophenols 2,4-di and 2,4,6-trichlorophenol in some Agent Orange samples, which contained, like PCP, a wide variety of PCDD/DF congeners. In this context, it may be expected that certain tactical herbicides contaminated with various chlorophenol impurities, have a unique congener pattern when compared with pure 2,4,5-T formulations.     

Lipid storage and composition in tropical surgeonfishes (Teleostei: Acanthuridae)

The lipid composition of tropical marine reef fishes is poorly known, despite their use as food by local human populations and recent interest in health-related benefits of fish lipids. We examined the composition of lipids from epaxial muscle, liver, and two storage sites [mesenteries surrounding the gut (intraperitoneal fat, IPFs) and retroperitoneal fat bodies (FBs) posterior to the peritoneal cavity] in three species of surgeonfishes from Ishigaki Island, Japan: Naso lituratus (Bloch and Schneider, 1801), Acanthurus lineatus (Linnaeus, 1758), and A. bariene (Lesson, 1830). Triacylglycerols dominated all samples of neutral lipid and constituted ≥ 99% of FBs and IPFs. Polar lipids generally contained large fractions of phosphatidylethanolamine and phosphatidylcholine. Quantified fatty acids ranged in length from C₁₄ to C₂₄. C₁₆ fatty acids prevailed (>35% of neutral fatty acids, >23% of polar fatty acids), although C₁₈ (>16 and >14%, respectively) and C₂₀ acids (>8 and >19%, respectively) were also common. Saturated fatty acids, dominated by palmitic acid (16:0), comprised 38.7 to 50.7% of acids from neutral lipids and 30.8 to 41.1% from polar lipids. The most common monounsaturated acids were 18:1n9 and 20:1n9. Polyunsaturated acids were prevalent in polar lipids (especially 20:4n6, 20:5n3, 22:2n3, 22:5n3, 22:5n6 and 22:6n3). Common polyunsaturated acids of neutral lipids were 18:2n6, 18:4n3, several n-3 and n-6 C₂₀ acids, 22:2n3 and 22:5n3. IPF and FB were almost identical across species, and lipids of fat bodies (IPFs, FBs) were more similar to those of muscle than those of liver for all three species. The FBs appear to constitute an accessory storage site, which overcomes constraints on lipid storage imposed by a small, inflexible abdominal cavity that contains both viscera and consistently voluminous gut contents. Fatty acid signatures indicate that largely overlooked epiphytic or epilithic diatoms contribute significantly to lipid acquisition. The combination of large quantities of both saturated and n-3 and other polyunsaturated fatty acids in surgeonfishes, in contrast to low saturates and high polyunsaturated acids in lipids of commercially important cool-water fishes, suggests that a study of dietary effects of fish lipids on human inhabitants of the tropics may be instructive insofar as human health and nutrition are concerned. Received: 16 March 1998 / Accepted: 6 August 1998