Predicted risk of childhood allergy, asthma, and reported symptoms using measured phthalate exposure in dust and urine.

UNLABELLED: The associated risk of phthalate exposure, both parent compounds in the home and their metabolites in urine, to childhood allergic and respiratory morbidity, after adjusting for exposures of indoor pollutants, especially bioaerosols, was comprehensively assessed. Levels of five phthalates in settled dust from the homes of 101 children (3-9 years old) were measured, along with their corresponding urinary metabolites. Other environmental risk factors, including indoor CO2, PM2.5, formaldehyde, 1,3-ß-D-glucan, endotoxin, allergen and fungal levels, were concomitantly examined. Subject's health status was verified by pediatricians, and parents recorded observed daily symptoms of their children for the week that the home investigation visit took place. Significantly increased level of benzylbutyl phthalate, in settled dust, was associated with test case subjects (allergic or asthmatic children). Higher levels of dibutyl phthalate and its metabolites, mono-n-butyl phthalate, and mono-2-ethylhexyl phthalate were found to be the potential risk factors for the health outcomes of interest. Similarly, indoor fungal exposure remained a significant risk factor, especially for reported respiratory symptoms. The relative contribution from exposure to phthalates and indoor biocontaminants in childhood allergic and respiratory morbidity is, for the first time, quantitatively assessed and characterized. PRACTICAL IMPLICATIONS: For asthmatic and allergic children living in subtropical and highly developed environments like homes in Taiwan, controlling environmental exposure of phthalates may be viewed as equally important as avoiding indoor microbial burdens, for the management of allergy-related diseases. It is also recognized that multidisciplinary efforts will be critical in realizing the true underlying mechanisms associated with these observations.

Inhibitory Effects of Chinese Medicinal Herbs on Plant-Pathogenic Bacteria and Identification of the Active Components from Gallnuts of Chinese Sumac.

The aqueous extracts of 30 out of 67 Chinese medicinal herbs were shown to have inhibitory effects on growth of Xanthomonas euvesicatoria by a paper disc diffusion assay. The inhibitory substances with the strongest antibacterial activity were extracted from Chinese sumac gallnut and black myrobalan. The aqueous extract of gallnut inhibited the growth of eight of the tested plant-pathogenic bacteria, and that of black myrobalan inhibited five. The gallnut extract produced at least an 8-mm inhibition zone against Acidovorax citrulli, Ralstonia solanacearum, X. citri pv. citri, and X. euvesicatoria at a 10-fold dilution, and it was still active at 800- to 1,600-fold dilutions. The aqueous extract of gallnut was more inhibitory than the acetone-water extract. To identify the inhibitory compounds in the gallnut aqueous extract, the crude extract was chromatographed over a silica column, and the primary compounds in fractions 3 and 8 were identified by nuclear magnetic resonance as gallic acid and methyl gallate, respectively. The inhibitory effect of methyl gallate on the growth of four plant-pathogenic bacteria was 10 to 80 times that of gallic acid. The minimum inhibition and minimum bactericidal concentration tests showed that the inhibition effect of the original aqueous was higher than that of methyl gallate. These results indicate that methyl gallate in gallnut is an important compound that is inhibitory to plant-pathogenic bacterial growth, and there are other unidentified compounds that are also responsible for the antibacterial effects. This is the first report regarding the antibacterial effects of gallnut extract and its chemical components on plant-pathogenic bacteria.

A dose-dependent relationship between the severity of visible mold growth and IgE levels of pre-school-aged resident children in Taiwan.

UNLABELLED: To demonstrate a dose-dependent relationship between severity of indoor visible mold growth and serum total IgE levels of resident children. A total of 97 children (4-7 years old) identified from previously established birth-cohort, with information pertaining to indoor environmental conditions after child's birth, were successfully recruited while sera were concurrently collected for total IgE and specific IgE analysis during clinical visits. Severity of visible mold growth at homes was scaled into three levels accordingly. A statistically significant dose-dependent relationship was found between severity of indoor visible mold growth and total serum IgE levels. The trend sustains after the model was adjusted for resident child's age, gender, pet-keeping history, number of siblings, atopic history of parents, presence of incense burning, and environmental tobacco smoking (ETS) at home. Further analysis of specific IgE to commonly examined fungal allergens did not substantiate the correlation. Rather, resident child's specific IgE to mite allergens, although without statistical significance, seemed to better associate with the ranked severity of indoor mold growth in this study. An adjuvant role of fungal exposure to enhance sensitization in indoor environment is therefore suggested in Taiwanese population with high prevalence of building dampness. PRACTICAL IMPLICATIONS: The presence of indoor visible mold growth, potentially resulting in fungal exposure, was not associated directly with changing biomarker levels of allergic response in resident children, rather playing an adjuvant role to enhance sensitization. On the other hand, other allergens, such as mite allergen examined in this study, appeared to support a more plausible etiology for directly triggering the ultimate allergic symptoms and diseases of interest. Evidence as such may derive different priority-setting when designing preventive measures for managing indoor air quality.

Markarian 348: a tidally disturbed seyfert galaxy.

Combined optical and radio images of galaxies can provide new insights into the sizes, masses, and possible evolution of these objects. Deep optical and neutral hydrogen images of Markarian 348, a type 2 Seyfert galaxy, show that it is a gigantic spiral (perhaps the largest known non-cluster galaxy). Measurements of the neutral hydrogen velocity field and spiral structure, and detection of an optical "tidal plume," all provide evidence that it has been subject to tidal disruption. The measured velocities yield a mass-to-light ratio for this object (within a radius of 130 kiloparsecs from its nucleus) that is similar to the ratio found for the inner regions of most galaxies of similar type. This is one of the few cases where detailed velocity measurements have demonstrated that a galaxy with an active nucleus has been subject to extensive tidal perturbation.

High variation of PCDDs, PCDFs, and dioxin-like PCBs ratio in cooked food from the first total diet survey in Taiwan.

This study determined the levels of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs), and dioxin-like polychlorinated biphenyls (dl-PCBs) in 240 individual food samples, belonging to 37 different foodstuffs in first total diet study (TDS) in Taiwan. The foods were collected from markets located in eight cities or counties around Taiwan. The food was cooked in a laboratory according to recipes typically used in Taiwan. In this study, PCDD/Fs were lower than the limits proposed by the European Union (EU) regulation for commercialized food, except for a notable PCDD/Fs level in ducks (3.660 pg WHO-TEQ/g, fat) obtained from central Taiwan. We hypothesize the duck meat might be probably polluted via emission of a fly ash recycling plant located near the duck farms. In addition to fish, most foods had high PCDD/Fs to dl-PCBs ratio. Needle fish and sea perch had relatively lower PCDD/Fs and dl-PCBs levels compared with those in other fish. Data from this study can be utilized for further consideration about dietary intake.

High average daily intake of PCDD/Fs and serum levels in residents living near a deserted factory producing pentachlorophenol (PCP) in Taiwan: influence of contaminated fish consumption.

An abandoned pentachlorophenol plant and nearby area in southern Taiwan was heavily contaminated by dioxins, impurities formed in the PCP production process. The investigation showed that the average serum PCDD/Fs of residents living nearby area (62.5 pg WHO-TEQ/g lipid) was higher than those living in the non-polluted area (22.5 and 18.2 pg WHO-TEQ/g lipid) (P<0.05). In biota samples, average PCDD/F of milkfish in sea reservoir (28.3 pg WHO-TEQ/g) was higher than those in the nearby fish farm (0.15 pg WHO-TEQ/g), and Tilapia and shrimp showed the similar trend. The average daily PCDD/Fs intake of 38% participants was higher than 4 pg WHO-TEQ/kg/day suggested by the world health organization. Serum PCDD/F was positively associated with average daily intake (ADI) after adjustment for age, sex, BMI, and smoking status. In addition, a prospective cohort study is suggested to determine the long-term health effects on the people living near factory.

First Report of the Causal Agent of Huanglongbing ("Candidatus Liberibacter asiaticus") Infecting Kumquat in Taiwan.

Huanglongbing (greening) disease caused by a nonculturable, phloem-limited bacterium is a severe disease of citrus. On the basis of the influence of temperature on host symptoms and the causal agent, this disease can be categorized as Asian caused by "Candidatus Liberibacter asiaticus", African caused by "Ca. L. africanus", and American caused by "Ca. L. americanus". Kumquat (Fortunella margarita (Lour.) Swingle), a member of the Rutaceae is an economically important crop for export and local consumption in Taiwan. Recently, a Huanglongbing-like disease was found on kumquat in Yilan County, the largest kumquat-producing area in northeastern Taiwan. Even though the disease has been reported on Citrus spp. from Taiwan, it has never been reported on kumquat. Symptoms of infected kumquat were mottling, yellowing, hardening, and curling of leaves followed by premature defoliation, twig dieback, decay of feeder rootlets and lateral roots, and ultimately the death of the entire plant. Typical sieve-tube-restricted bacteria were observed in kumquat cells by electron microscopy (1). In addition, psyllid-transmission tests demonstrated that the Asian psyllid (Diaphorina citri) could transmit this bacterium to healthy kumquats. Positive bud graft transmissions were obtained to F. margarita, F. japonica (Thunb.) Swingle, F. obovata Hort. ex Tanaka, Luchen sweet orange (Citrus sinensis (L.) Osb.), and Wentan pummelo (C. maxima f. sp. butan Hay.). These inoculated plants showed symptoms in 3 to 8 months, and bacteria could be detected by polymerase chain reaction (PCR) using a common primer pair that amplified a 226-bp specific DNA fragment (2). For further molecular identification, the bacterial DNA was extracted from the inoculated plants and PCR was performed by using two sets of primers selected from the 16S rRNA region (GenBank Accession No. L22532) and 16S/23S intergenic spacer region (GenBank Accession No. AB019793). The expected DNA fragments of 1,389 bp and 862 bp were, respectively, amplified from symptomatic plants but not from healthy plants. The PCR products were cloned and sequenced (GenBank Accession Nos. DQ302750 and DQ207841). The 16S rRNA has 98 to 99% identity and 16S/23S intergenic spacer region has 99% identity to the corresponding region of "Ca. L. asiaticus" in GenBank. These molecular analyses confirm the presence of "Ca. L. asiaticus" in kumquat. Since Huanglongbing has been rarely reported naturally on kumquat, further analysis of this bacterium as a special strain of "Ca. L. asiaticus" is needed. References: (1) M. Garnier et al. Ann. Microbiol. 135A:169, 1984. (2) T. H. Hung et al. J. Phytopathol. 147:599, 1999.

First Report of Bougainvillea spectabilis chlorotic vein-banding virus Infecting Bougainvillea Plants in Taiwan.

Bougainvillea (Bougainvillea spectabilis), native to Amazonian rainforests in South America, is an important ornamental and landscaping plant that is widely distributed in tropical and subtropical areas. A new virus disease, Bougainvillea chlorotic vein-banding, caused by a Badnavirus, Bougainvillea spectabilis chlorotic vein-banding virus (BsCVBV), was first reported in Brazil in 2001 (1) and recently discovered in Taiwan. Infected bougainvillea developed symptoms such as mottling, chlorosis, vein-banding, and stunting. Severe leaf-distortion symptoms were observed in the susceptible hybrid Taipei Red, the most popular bougainvillea cultivar in Taiwan. In electron microscopic observations, typical bacilliform virions measuring 28 × 130 to 150 nm were observed in infected bougainvillea cells. In addition, our transmission tests demonstrated that the virus could be easily transmitted among different bougainvillea cultivars by bud grafting but not by mechanical inoculation. Bougainvillea plants showed apparent symptoms 1 month after grafting. For molecular identification, viral DNA was extracted from the test plants (2), and polymerase chain reaction (PCR) was performed using the primers selected from the DNA sequences of ORF III of Sugarcane bacilliform virus (GenBank Accession No. M89923). The sequence of the forward primer was 5'-TCA AAG TTT GAT TTG AAG AGC GGG-3' and the sequence of the reverse primer was 5'-CTT GCA TAC TGC TCC CCA TCC-3' The primers amplified a 676-bp PCR product (GenBank Accession No. DQ103759). Nucleotide and deduced amino acid sequences were 82 and 90% identical, respectively, to the corresponding region of the Brazilian strain of BsCVBV (GenBank Accession No. AY532653). These data indicate that the bougainvillea disease occurring in Taiwan is caused by a strain of BsCVBV. Reference: (1) C. M. Chagas et al. Virus Rev. Res. 6:153, 2001. (2) H.-J. Su et al. J. Phytopathol. 151:290, 2003.

Simple two-color array-based approach for mutation detection.

The ability to analyze multiple polymorphic/mutation sites rapidly and accurately is pivotal in all areas of genetic analysis. We have applied single nucleotide primer extension (SNE) for detection of multiple point mutations in a micro-array format using two-color, fluorescent dye-tagged dideoxynucleoside triphosphate terminators (ddNTPs). The oligonucleotide primer ending one nucleotide short of the mutation site being probed is bound to the slide and single-base extended in place with two different Cy5/Cy3 dye-tagged terminators using solution-phase, locus-specific, single-stranded complementary templates generated by PCR from genomic DNA. The composite fluorescence produced contains peaks of distinct wave lengths corresponding to each Cy dye-tagged terminator incorporated, resulting in a fluorescent 'fingerprint' for each DNA target. DNA polymerase-catalyzed incorporation of Cy dye-tagged dideoxynucleoside triphosphates was dependent on the particular dyes, the specific ddNTP, the DNA target concentration, sequence of the template, on-slide temperature cycling and washing conditions. Results from analysis of mutations in the human hemochromatosis and connexin 26 genes show that this approach has several advantages over existing methods and is simple, rapid, robust, cost effective and accurate with potential applications in many areas of genetic analysis.

Four-laser scanning confocal system for microarray analysis.

We have constructed a confocal scanner suitable for routine microarray analysis from commercially available parts. We have outlined the details that should be considered when designing such an instrument and listed some of the specific components comprising the system [the full list of system components is available on CD from the corresponding author (D.J.G.) at no charge]. Here, we describe the methods used to test the linearity and sensitivity of the instrument. Performance was evaluated with two commonly used dyes, fluorescein and Cy5. While the instrument had a linear correlation between the dye concentration and fluorescence intensity, the observed deviation from a slope of 1.0 underscores the importance of running multipoint calibration experiments to obtain accurate dye quantitation over the full dynamic range of the scanner. This method has utility in testing commercial instruments in addition to the scanner described here. An array with over 300 spots dyed with Cy3 was scanned with our instrument and a high-end commercial instrument. The agreement between the two instruments was very good over a 1000-fold intensity range. Our scanner is a cost-effective alternative to more costly commercial scanners with similar capabilities.

Climate, traffic-related air pollutants, and asthma prevalence in middle-school children in taiwan.

This study compared the prevalence of asthma with climate and air pollutant data to determine the relationship between asthma prevalence and these factors. We conducted a nationwide survey of respiratory illness and symptoms in middle-school students in Taiwan. Lifetime prevalences of physician-diagnosed asthma and of typical symptoms of asthma were compared to air monitoring station data for temperature, relative humidity, sulfur dioxide, nitrogen oxides, ozone, carbon monoxide, and particulate matter with aerodynamic diameter [less than/equal to] 10 microm (PM(10)). A total of 331,686 nonsmoking children attended schools located within 2 km of 55 stations. Asthma prevalence rates adjusted for age, history of atopic eczema, and parental education were associated with nonsummer (June-August) temperature, winter (January-March) humidity, and traffic-related air pollution, especially carbon monoxide and nitrogen oxides, for both girls and boys. Nonsummer temperature, winter humidity, and traffic-related air pollution, especially carbon monoxide and nitrogen oxides, were positively associated with the prevalence of asthma in middle-school students in Taiwan.

Susceptibility of endothelial cells to bovine herpesvirus type 4 (BHV-4).

The sensitivity of two different types of cells to bovine herpesvirus type 4 (BHV-4) was compared by median tissue culture infectious dose (TCID50) assays. The bovine arterial endothelial (BAE) cell culture derived from bovine carotid arteries was 100-1000 times more sensitive to two strains of BHV-4, Movar 33/63 and DN 599, than Madin Darby bovine kidney (MDBK) cell line commonly used for the propagation of these viruses. BAE cell cultures infected with BHV-4 displayed cytopathic effects (CPE) earlier and more prominently than the MDBK cells infected with the same viruses. BAE cells were also more sensitive than MDBK cells in conventional plaque assays in that the former developed well characterized and easily recognized plaques after infection with the viruses. BAE cells, which are proved to be exceptionally susceptible to BHV-4, can be used in the detection and quantitation of BHV-4.

Reductions in binding and functions of D2 dopamine receptors in the rat ventral striatum during amphetamine sensitization.

Rats receiving amphetamine (5 mg/kg, i.p. once daily) for 14 continuous days develop behavioral sensitization to a subsequent amphetamine challenge (1 mg/kg) at withdrawal days 8 to 10. The present study was aimed at investigating whether there are changes in binding or functions of striatal D2 dopamine receptors in amphetamine-sensitized rats. The results indicated that the Bmax value of D2 receptors in the ventral striatum decreased 40% and 52% 7 and 10 days after amphetamine withdrawal, respectively, without changes in their binding affinities (Kd). During this withdrawal period, the D(2/3) receptor agonist-induced (a) locomotor activation (bromocriptine, 5 mg/kg, i.p. or quinpirole, 1 mg/kg, i.p.) and (b) inhibition of forskolin-enhanced adenylyl cyclase activity (bromocriptine, 50 or 150 microM) in the ventral striatum were both suppressed as compared with saline controls. The decreases in D2 receptor function were unrelated to the coupled G-proteins, since none of the G alpha i-3, G alpha o or G alpha q in the ventral striatum exhibited quantitative differences between control and amphetamine sensitized rats. Collectively, these results demonstrate that intermittent amphetamine administration for a period of 14 days leads to diminished D2 receptor expression and functions in the ventral striatum at late withdrawal periods. The decrease of D2 receptors might reflect cellular mechanisms underlying the expression of amphetamine sensitization.

Different cell death mechanisms and gene expression in human cells induced by pentachlorophenol and its major metabolite, tetrachlorohydroquinone.

Pentachlorophenol (PCP) and its salt are used extensively as biocide and wood preservative. Due to improper disposal, PCP has become an environmental pollutant and is now considered to be ubiquitos. Metabolic studies carried out in rodents or human liver homogenate have indicated that PCP undergoes oxidative dechlorination to form tetrachlorohydroquinone (TCHQ). The cytotoxicity, cell death mechanisms and gene expression of PCP and TCHQ are investigated in human liver and bladder cells and show that TCHQ induces apoptosis and DNA genomic fragmentation in bladder cells but not liver cells. No apoptotic features could be induced by treatment of PCP in both cell lines. The concentrations of PCP required to cause 50% cell death in T-24 and Chang liver cells were 5-10-fold greater than the concentrations of TCHQ. Several gene products are important in controlling the apoptotic and necrotic processes. Of these, hsp 70, CAS, bcl-2 and bax were studied. The expression of the hsp70 gene increased significantly (2-3-fold) in cells treated with TCHQ. However, no significant change was found in the cells treated with PCP. The expression of CAS gene decreased significantly in T-24 cells treated with both TCHQ and PCP. Whereas, no significant change was found in Chang liver cells with the same treatment. In addition, the expression of the bcl-2/bax protein decreased significantly in these two cell lines treated with TCHQ but not PCP.

The topical application of 2,3,7,8-tetrachlorodibenzo-p-dioxin lacks skin tumor-promoting potency but induces hepatic injury and tumor necrosis factor-alpha expression in ICR male mice.

One of the most toxic environmental pollutants known to man is 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). There is growing evidence that indicates TCDD is a potent tumor promoter in rat and mouse liver, as well as in mouse skin. The mouse skin carcinogenesis model has been used extensively to assess whether a chemical or physical agent carries a carcinogenic hazard to humans and to define the mechanism involved with the carcinogenic effects. We applied the mouse skin model to ICR male mice and the results showed that following the application of DMBA, repeated dorsal application of all doses of TCDD produced no papillomas. These findings imply that the ICR male mouse is an extremely insensitive strain as a TCDD-induced two-stage mouse skin carcinogenesis model. However, severe hepatic injuries and wasting syndrome were seen in mice treated topically with TCDD. Meanwhile, serum TNF-alpha levels increased during the experimental periods. Inflammatory cell infiltration, fatty liver, and nodule formation could be observed in damaged livers. Elevated hepatic EROD activity and urinary 8-epi-PGF2alpha were also observed in mice with short-term exposure of TCDD.

Serum PCDD/F concentration distribution in residents living in the vicinity of an incinerator and its association with predicted ambient dioxin exposure.

The aim of this study was to evaluate the serum polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) concentration distribution in residents living in the vicinity of an incinerator and its association with annual ambient dioxin exposure predicted by an atmospheric dispersion model. A municipal waste incinerator in Northern Taiwan was chosen for this study. This incinerator had been in operation for 6 years at the time of this study. Using the incinerator site as the center, based on the simulated ambient annual average PCDD/F concentrations. Ninety-five volunteers, all live within a radius of 5 km from the incinerator for at least 5 years, who had no occupational exposure potential, were selected based on the population distribution in each district. The average serum PCDD/F concentration for these subjects living within four zones was about 14 pg I-TEQ/g lipid. The serum distribution levels of people of the four study zones, however, were not consistent with the predicted ambient levels. Results also suggest that ambient exposure might not be the most important contributor to serum concentrations when compared to other exposure sources, such as dietary intake.

First Report of Papaya leaf curl virus Infecting Papaya Plants in Taiwan.

Papaya leaf curl disease was first reported in India in 1939 (1). Caused by begomovirus, Papaya leaf curl virus (PaLCV) (2), this disease was discovered in the papaya orchards of southern Taiwan in 2002. Infected papaya developed symptoms such as downward curling of leaves, twisted petioles, vein enation, and stunting. Diseased plants produced small and distorted fruits that tend to fall prematurely. Typical twin virion was observed in the diseased papaya cells by electron microscopy. In addition, our whitefly-transmission test demonstrated that the sweet potato whitefly (Bemisia tabaci) could transmit this virus. For further molecular identification, two opposing primers were selected for the polymerase chain reaction (PCR) detection of PaLCV from the published nucleotide sequences of PaLCV (Genbank Accession No. NC004147) (3). The primer pair, composed of the forward primer 5' -GCT AGA AAT TAT GTC GAA GCG-3' and the reverse primer 5'-TCA ACT ACA ACC TGA GGA AAG C-3', was designed to amplify a PaLCV-specific 1,031-bp fragment containing 774 bp of the coat protein gene open reading frame (CP-ORF) using PCR. Five diseased papaya samples with typical leaf-curl symptoms tested positive in the PCR-based assay with this specific primer pair, whereas five healthy papaya samples tested negative. However, the sequencing results of the PCR product from five PaLCV-infected papayas indicated the CP-ORF of PaLCV in Taiwan (PaLCV-Tw) was somewhat different from PaLCV in India (PaLCV-Id). The DNA sequences (Genbank Accession No. AY183472) of CP-ORF of PaLCV-Tw were 80% identical to those of PaLCV-Id, and their translated amino acid sequences were 77% identical. This indicates that PaLCV-Tw and PaLCV-Id are two different species or strains. References: (1) K. M. Thomas and C. S. Krishnaswamy. Curr. Sci. 8:316,1939. (2) S. Saxena et al. Plant Dis. 82:126, 1998. (3) S. Saxena et al. Biochem. Mol. Biol. Int. 45:101, 1998.

Fungal exposure of children at homes and schools: a health perspective.

The authors investigated airborne fungal exposure of Taiwanese children at homes and schools-locations where they spent the majority of their time. Pairs of asthmatic and healthy children, matched by age, gender, classes (schools), and residence, participated in the study. Airborne fungal concentrations at homes and schools, and time-activity data of the study subjects were collected. In winter, the indoor geometric mean concentration was 9,672.1 colony-forming units per cubic meter and 4,380.9 colony-forming units per cubic meter in summer. The indoor/outdoor concentration ratio was similar in all homes for both seasons. Fungal concentrations in southern Taiwan were high during both winter and summer. Personal fungal exposure was not statistically different between asthmatic and nonasthmatic children, after adjustment of time-activity patterns. Higher symptom scores were shown for children in homes with higher fungal exposures.

Biochemical study of retired pentachlorophenol workers with and without following dietary exposure to PCDD/Fs.

PCDD/Fs are found as impurities in commercial pesticide sodium pentachlorophenol (Na-PCP) salt. We compared, using multivariate logistic regression analysis adjusted for confounding factors, serum PCDD/F levels and biochemical examinations of retired Na-PCP workers and other inhabitants living near a closed Na-PCP plant that discharged PCP-contaminated wastewater into a nearby pond in Tainan, Taiwan. In this cross-sectional study from October 2006 through May 2009, 1167 participants were divided into groups according to their occupational (retired Na-PCP plant workers versus other residents) and dietary exposure (eating polluted fish versus not eating polluted fish) to PCDD/Fs, and a general population from a large-scale survey. Serum PCDD/F levels were significantly different between these groups (range: from 22.9±10.0pg WHO(98)-TEQ(DF) g(-1) lipid in the general population to 109.6±94.5pg WHO(98)-TEQ(DF) g(-1) lipid in retired Na-PCP workers eating polluted seafood; P(trend)<0.001). Distinct patterns of PCDD/Fs congener profiles, showing a significantly higher proportion of 1,2,3,7,8-PeCDD, 1,2,3,6,7,8-HxDD, and less 2,3,4,6,7,8-HpCDF, OCDF, were also found among workers and residents with different serum PCDD/F levels versus the general population. After adjusting for confounding factors, glucose (adjusted odds ratio [AOR] 7.22 [95% CI: 4.04-12.90]), triglycerides (AOR 4.31 [95% CI: 2.57-7.22]), blood urea nitrogen (AOR 2.90 [95% CI: 1.58-5.33]), creatine (AOR 5.83 [95% CI: 1.12-30.30]) and total protein (AOR 3.74 [95% CI: 1.91-7.31]) levels in retired workers were significantly higher than in the reference group. Occupational exposure to PCDD/Fs is associated with biochemical abnormalities that may persist for years after serum PCDD/F levels have declined.