Genomic overview of INA-induced NPR1 targeting and transcriptional cascades in Arabidopsis.

The phytohormone salicylic acid (SA) triggers transcriptional reprogramming that leads to SA-induced immunity in plants. NPR1 is an SA receptor and master transcriptional regulator in SA-triggered transcriptional reprogramming. Despite the indispensable role of NPR1, genome-wide direct targets of NPR1 specific to SA signaling have not been identified. Here, we report INA (functional SA analog)-specific genome-wide targets of Arabidopsis NPR1 in plants expressing GFP-fused NPR1 under its native promoter. Analyses of NPR1-dependently expressed direct NPR1 targets revealed that NPR1 primarily activates genes encoding transcription factors upon INA treatment, triggering transcriptional cascades required for INA-induced transcriptional reprogramming and immunity. We identified genome-wide targets of a histone acetyltransferase, HAC1, including hundreds of co-targets shared with NPR1, and showed that NPR1 and HAC1 regulate INA-induced histone acetylation and expression of a subset of the co-targets. Genomic NPR1 targeting was principally mediated by TGACG-motif binding protein (TGA) transcription factors. Furthermore, a group of NPR1 targets mostly encoding transcriptional regulators was already bound to NPR1 in the basal state and showed more rapid and robust induction than other NPR1 targets upon SA signaling. Thus, our study unveils genome-wide NPR1 targeting, its role in transcriptional reprogramming, and the cooperativity between NPR1, HAC1, and TGAs in INA-induced immunity.

Negative evidence on the transgenerational inheritance of defense priming in Arabidopsis thaliana.

Defense priming allows plants to enhance their immune responses to subsequent pathogen challenges. Recent reports suggested that acquired resistances in parental generation can be inherited into descendants. Although epigenetic mechanisms are plausible tools enabling the transmission of information or phenotypic traits induced by environmental cues across generations, the mechanism for the transgenerational inheritance of defense priming in plants has yet to be elucidated. With the initial aim to elucidate an epigenetic mechanism for the defense priming in plants, we reassessed the transgenerational inheritance of plant defense, however, could not observe any evidence supporting it. By using the same dipping method with previous reports, Arabidopsis was exposed repeatedly to Pseudomonas syringae pv tomato DC3000 (Pst DC3000) during vegetative or reproductive stages. Irrespective of the developmental stages of parental plants that received pathogen infection, the descendants did not exhibit primed resistance phenotypes, defense marker gene (PR1) expression, or elevated histone acetylation within PR1 chromatin. In assays using the pressure-infiltration method for infection, we obtained the same results as above. Thus, our results suggest that the previous observations on the transgenerational inheritance of defense priming in plants should be more extensively and carefully reassessed. [BMB Reports 2022; 55(7): 342-347].

Salicylic acid-induced transcriptional reprogramming by the HAC-NPR1-TGA histone acetyltransferase complex in Arabidopsis.

Plant immunity depends on massive expression of pathogenesis-related genes (PRs) whose transcription is de-repressed by pathogen-induced signals. Salicylic acid (SA) acts as a major signaling molecule in plant immunity and systemic acquired resistance triggered by bacterial or viral pathogens. SA signal results in the activation of the master immune regulator, Nonexpressor of pathogenesis-related genes 1 (NPR1), which is thought to be recruited by transcription factors such as TGAs to numerous downstream PRs. Despite its key role in SA-triggered immunity, the biochemical nature of the transcriptional coactivator function of NPR1 and the massive transcriptional reprogramming induced by it remain obscure. Here we demonstrate that the CBP/p300-family histone acetyltransferases, HACs and NPR1 are both essential to develop SA-triggered immunity and PR induction. Indeed HACs and NPR1 form a coactivator complex and are recruited to PR chromatin through TGAs upon SA signal, and finally the HAC-NPR1-TGA complex activates PR transcription by histone acetylation-mediated epigenetic reprogramming. Thus, our study reveals a molecular mechanism of NPR1-mediated transcriptional reprogramming and a key epigenetic aspect of the central immune system in plants.

Phthalate concentrations and dietary exposure from food purchased in New York State.

BACKGROUND: Phthalates have been found in many personal care and industrial products, but have not previously been reported in food purchased in the United States. Phthalates are ubiquitous synthetic compounds and therefore difficult to measure in foods containing trace levels. Phthalates have been associated with endocrine disruption and developmental alteration. OBJECTIVES: Our goals were to report concentrations of phthalates in U.S. food for the first time, specifically, nine phthalates in 72 individual food samples purchased in Albany, New York, and to compare these findings with other countries and estimate dietary phthalate intake. METHODS: A convenience sample of commonly consumed foods was purchased from New York supermarkets. Methods were developed to analyze these foods using gas chromatography-mass spectroscopy. Dietary intakes of phthalates were estimated as the product of the food consumption rate and concentration of phthalates in that food. RESULTS: The range of detection frequency of individual phthalates varied from 6% for dicyclohexyl phthalate (DCHP) to 74% for di-2-ethylhexyl phthalate (DEHP). DEHP concentrations were the highest of the phthalates measured in all foods except beef [where di-n-octyl phthalate (DnOP) was the highest phthalate found], with pork having the highest estimated mean concentration of any food group (mean 300 ng/g; maximum, 1,158 ng/g). Estimated mean adult intakes ranged from 0.004 µg/kg/day for dimethyl phthalate (DMP) to 0.673 µg/kg/day for DEHP. CONCLUSIONS: Phthalates are widely present in U.S. foods. While estimated intakes for individual phthalates in this study were more than an order of magnitude lower than U.S. Environmental Protection Agency reference doses, cumulative exposure to phthalates is of concern and a more representative survey of U.S. foods is indicated.

Persistent organic pollutants including polychlorinated and polybrominated dibenzo-p-dioxins and dibenzofurans in firefighters from Northern California.

Polychlorinated and polybrominated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs and PBDD/Fs) were measured in serum of twelve firefighters sampled after a fire event in San Francisco, California, along with polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), p,p'-DDE, hexachlorobenzene (HCB), perfluorinated chemicals (PFCs), bisphenol-A (BPA) and tetrabromobisphenol-A (TBBPA). TEQPCDD/F concentrations were relatively low (mean 5pgg(-1) (lipid weight), lw, range 1-11pgg(-1)lw), but concentrations of 1,2,3,4,6,7,8-HpCDD, a congener indicative of exposure during firefighting, were elevated. Tentative WHO2005-TEQs calculated for PBDD/Fs in our samples (mean 104pgg(-1)lw, range 0.2-734pgg(-1)lw) suggested that PBDD/Fs may contribute substantially to dioxin-like toxicity in individual firefighters. PBDE concentrations were elevated in firefighter serum (mean 135ngg(-1)lw, range 48-442ngg(-1)lw). PBDE-209, PBDE-47 and PBDE-153 were prevalent congeners; PBDE-209 contributed >50% of the total PBDE concentration in four individuals, implying continuous occupational exposure to deca-BDE. Perfluorooctanesulfonate (PFOS) was the dominant PFC in serum (mean 12ngml(-1) (wet weight), ww, range 3ngml(-1)ww to 59ngml(-1)ww), followed by perfluorooctanoic acid (PFOA) (mean 7ngml(-1)ww, range 2ngml(-1)ww to 12ngml(-1)ww). Concentrations of perfluorononanoic acid (PFNA) (mean 2ngml(-1)ww, range 1-4ngml(-1)ww) were higher than those reported in the high-smoke exposure group of World Trade Center fire responders, suggesting that the California firefighters were exposed to PFNA in smoke during firefighting. Given their elevated rates of cancers, these results illustrate the importance of monitoring halogenated contaminants including PBDD/Fs in firefighters.

Immune function in female B(6)C(3)F(1) mice is modulated by DE-71, a commercial polybrominated diphenyl ether mixture.

Polybrominated diphenyl ethers (PBDEs) are an important class of flame-retardants that are environmentally persistent and bioaccumulative. Toxicity of these compounds has become a concern because detectable levels of PBDEs are present in humans and wildlife and they are structurally similar to polychlorinated biphenyls (PCBs). This study examined the effects of the commercial penta-BDE mixture, DE-71, in adult female B(6)C(3)F(1) mice on hematology, serum clinical chemistry, thyroid hormones, tissue histology, and several immunotoxicity end-points (lymphocyte proliferation, NK cell activity, splenic immunophenotypes, and SRBC-specific-IgM production). Mice were exposed via oral gavage for 28 days to achieve total administered doses (TAD) of 0, 0.5, 5, 50, or 100 mg/kg. No changes in histology, clinical chemistry, body or organ weights were observed. Serum total T3 and T4 levels were not altered by any of the DE-71 treatments. Peripheral blood monocyte numbers were decreased by the 0.5, 5, and 50 mg/kg treatments, but not by the 100 mg/kg TAD concentration. Compared to controls, mitogen-stimulated T- and B-cell proliferation was increased by the 100 mg/kg TAD concentration (ED(50) = 60 mg/kg TAD [2.14 mg/kg/day] and 58 mg/kg TAD [2.57 mg/kg/day], respectively). NK cell activity was decreased compared to controls by the 100 mg/kg TAD concentration (ED(50) = 20 mg/kg TAD [0.7 mg/kg/day]). No alterations were noted in thymic T-cell populations or in SRBC-specific-IgM production. Numbers of CD19(+)CD21(-), CD19(+)CD21(+), CD4(+)CD8(-), CD4(-)CD8(+), CD4(-)CD8(-), and MHC-II(+) cells in the spleen were not affected. However, the numbers of splenic CD4(+)CD8(+) cells were decreased compared to the controls by 0.5, 5, and 100 mg/kg TAD. This study provides an assessment of the systemic toxicity and immunotoxicity of DE-71, and indicates that immune parameters are modulated at exposure concentrations lower than previously reported.

Distribution of mono- through hexa-chlorobenzenes in floodplain soils and sediments of the Tittabawassee and Saginaw Rivers, Michigan.

INTRODUCTION: Chlorobenzenes are used as solvents or as feedstocks in the production of pesticide formulations, dyes, room deodorizers, moth-proofing agents, and de-inking solvents. Chlorobenzenes were produced by the Dow Chemical Company in Midland, Michigan, for several decades. In this study, concentrations of 12 chlorobenzene (CBz) congeners, from mono- to hexachlorobenzenes, were measured in more than 150 floodplain soil (FPS), surface sediment, and sediment core (SC) samples collected during 2002-2004 from the Pine River, Tittabawassee River, Shiawassee River, Saginaw River, and Saginaw Bay, Michigan. METHODS: Five grams of wet sediment were homogenized with anhydrous sodium sulfate and extracted with 20% dichloromethane/hexane. The extracts were purified by silica gel column chromatography and analyzed by a gas chromatograph interfaced with a mass spectrometer (GC/MS). RESULTS: Mean concentrations of ΣCBz in FPS and surface sediment were seven to 30 times higher in the Tittabawassee River (80 and 60 ng/g dry weight (dw), respectively) than in the Saginaw River (2.4 and 8.1 ng/g dw, respectively) and Saginaw Bay (5.5 and 8.0 ng/g dw, respectively). Concentrations of ΣCBz were low in surface sediment and FPS from locations upstream of Midland, Michigan, on the Tittabawassee River. Concentrations of ΣCBz were higher in FPS than in surface sediment of the Tittabawassee River; on the contrary, surface sediment contained higher concentrations of CBz than FPS from the other rivers studied. High concentrations of hexachlorobenzene were found in FPS of the Tittabawassee River. All CBz congeners, except for dichlorobenzenes (DCBz), showed a trend of spatial decrease with downstream of the Dow Chemical Company in Midland. The CBz congener composition of the samples showed multiple patterns that reflected differences in historical emissions and environmental partitioning, arising from variations in physico-chemical properties of CBz. 1,4-Dichlorobenzene (1,4-DCBz) was found in all of the samples and accounted for a high proportion of total CBz. The relationship between concentrations of CBz and previously reported concentrations of PCDD/Fs for the same set of samples (Kannan et al. 2008) was significant, indicating similarities in sources and depositions of these two classes of compounds in the watershed.

Effects of environmentally-relevant levels of perfluorooctane sulfonate on clinical parameters and immunological functions in B6C3F1 mice.

In the first part of a series of studies to account for perfluorooctane sulfonate (PFOS)-induced sheep red blood cell (SRBC)-specific immunoglobulin M (IgM) antibody suppression in mice, a survey of clinical and immunotoxicological endpoints was examined. Adult female B6C3F1 mice were exposed orally for 28 days to a total administered dose (TAD) of 0, 0.1, 0.5, 1, or 5 mg PFOS/kg. Uterus wet weight was significantly decreased compared with control at the 5 mg/kg dose. No indications of wasting syndrome, malnutrition, alteration of thyroid homeostasis, or signs of overt toxicity were observed. Numbers of splenic CD19+/CD21⁻, CD19+/CD21+, B220+/CD40+, CD4+/CD154⁻, CD4+/CD154+, and MHC-II+ cells were not altered. Additionally, ex vivo interleukin-4 (IL-4), IL-5, and IL-6 production by in vitro anti-CD3- or phorbol myristate acetate-stimulated CD4+ T-cells was not affected. Ex vivo IL-6 production by B-cells was significantly increased by in vitro stimulation with either anti-CD40 or lipopolysaccharide. Increased IL-6 production by B-cells was the most sensitive endpoint assessed resulting in alterations at the lowest dose tested (0.1 mg/kg TAD) following anti-CD40 stimulation. Further studies are required to characterize effects on inflammatory markers such as IL-6 at environmentally relevant concentrations of PFOS and to determine the key events associated with PFOS-induced IgM suppression to address potential human health risks.

Occurrence of synthetic musks in indoor dust from China and implications for human exposure.

Synthetic musk compounds are used in a wide range of personal care and other consumer products. Despite this fact, few studies have reported the occurrence of synthetic musks in house dust or exposure of humans through the ingestion of indoor dust. In the present study, we determined the concentrations and profiles of two polycyclic musks (PCMs; Galaxolide(®) [HHCB] and Tonalide(®)), three nitro musks (NMs; musk ketone [MK], musk moskene [MM], and musk xylene [MX]), and one metabolite of HHCB (HHCB-lactone), in 88 indoor-dust samples from homes, dormitories, offices, and laboratories in China. In addition, we analyzed 12 dust samples collected from inside the housings of electrical/electronic devices that were located in 10 of the houses. Synthetic musks were detected in all of the dust samples analyzed, with total concentrations (sum of PCM and NM concentrations) varying from 4.42 to 688 ng g⁻¹ (mean ± SD: 126 ± 16.2 ng g⁻¹; median: 82.7 ng g⁻¹). HHCB was the predominant compound in all of the dust samples analyzed accounting on average for 42.2% of the total musk concentrations. Concentrations of synthetic musks in dust samples from homes and offices were higher than the concentrations found in samples from dormitories and laboratories. Concentrations of synthetic musks in dust samples increased with the increasing number of occupants in homes. Based on the concentrations, levels of exposure to musks by way of dust ingestion were calculated to be up to 25.8 ng d⁻¹ for adults and 138 ng d⁻¹ for toddlers.

Occurrence of cyclic and linear siloxanes in indoor dust from China, and implications for human exposures.

Siloxanes are used in a wide variety of personal-care and other consumer products. Although there is clearly a potential for contamination of indoor dust with siloxanes, reports of occurrence of siloxanes in indoor dust were not available, prior to the present study. Here, we have determined the concentrations and profiles of four cyclic siloxanes, octamethylcyclotetrasiloxane (D(4)), decamethylcyclopentasiloxane (D(5)), dodecamethylcyclohexasiloxane (D(6)), and tetradecamethylcycloheptasiloxane (D(7)), as well as 11 linear siloxanes, from L(4)-L(14), in 100 dust samples collected in China. Cyclic and linear siloxanes were found in all dust samples, with the linear siloxanes L(9)-L(14) being the predominant compounds. Concentrations of total siloxanes in dust ranged from 21.5 to 21,000 (mean: 1540 +/- 2850) ng g(-1). The highest concentration of the individual linear siloxanes, L(9)-L(14), ranged between 2680 and 6170 ng g(-1). Concentrations of total linear siloxanes (TLS) were 1-2 orders of magnitude higher than concentrations of total cyclic siloxanes (TCS), in all indoor dust samples. Siloxane concentrations in dust were associated with the number of electrical/electronic appliances, number of occupants, and smokers living in the house. Based on the measured siloxane concentrations and on estimated daily ingestion rates of dust by toddlers and adults, we calculated the daily intake of siloxanes. For adults, daily exposure to total siloxanes, based on an average dust intake rate and median exposure concentration, was calculated to be 15.9 ng day(-1); the corresponding value for toddlers was 32.8 ng d(-1).

High concentrations of persistent organic pollutants including PCBs, DDT, PBDEs and PFOS in little brown bats with white-nose syndrome in New York, USA.

White-nose syndrome (WNS) is a condition associated with white fungal growth on ears, wings, and nose of hibernating bats; this condition has recently resulted in high bat mortality in the northeastern United States. Nevertheless, the pathogenesis of morbidity and mortality are still unknown. Elevated exposure to toxic contaminants could be a contributing factor via the consequent immunosuppression and endocrine disruption. In this study, diseased little brown bats (Myotis lucifugus) were collected from several hibernacula in eastern New York State in 2008. Fat tissues of bats were analyzed for polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls (PBBs), and organochlorine pesticides (OCPs; DDT, chlordanes, HCB, and HCH), and liver was analyzed for perfluorinated compounds (PFCs). A reference population of little brown bats, not affected by WNS, was also collected from a cave in Kentucky for the analysis of trace organic contaminants. Concentration of PCBs in fat tissues of bats from New York ranged from 1900 ng g(-1) to 35000 ng g(-1), lipid wt, with the highest concentrations found in bats collected from caves in Albany County. High concentrations of PCBs were also found in bats from Kentucky (17100-18400 ng g(-1), lipid wt). Total PBDE concentrations in fat tissues ranged from 520 ng g(-1) to 10900 ng g(-1), lipid wt, in bats from New York and from 4300 ng g(-1) to 13000 ng g(-1), lipid wt, in bats from Kentucky. High concentrations of DDT (26900 ng g(-1), lipid wt), chlordanes (6350 ng g(-1), lipid wt), and HCB (260 ng g(-1), lipid wt) were found in bats from New York. Concentrations of hexabromobiphenyl congener 153 (PBB 153) in bats from New York ranged from 8.6ngg(-1) to 124000 ng g(-1), lipid wt. Concentrations of PFCs were on the order of a few tens to a few hundreds of nanograms per gram liver, on a wet weight basis. Overall, high concentrations of PCBs, PBDEs, DDT, and chlordanes were found in fat tissues of diseased bats from New York, although the concentrations in bats from non-diseased, reference population, from Kentucky were also high.

Polybrominated diphenyl ethers and synthetic musks in umbilical cord serum, maternal serum, and breast milk from Seoul, South Korea.

Fetal and maternal exposure levels of two emerging pollutants, polybrominated diephenyl ethers (PBDEs) and synthetic musks, were measured in Korean general population to assess prenatal and postnatal exposures in infants. For this purpose, paired samples of breast milk, maternal and cord blood were collected from 20 Korean women in 2007. In comparison to data from other countries and previous data from Korea, relatively higher and gradually increasing concentrations for PBDEs were found in Korean breast milk (< LOQ to 590 ng g(-1) lipid wt; median=90 ng g(-1)). Differences in PBDEs and musk concentrations were found among age groups and parity levels. PBDEs concentrations in breast milk were lower in the younger mothers and/or the mothers with multiple parities, while these trends were not found for musks. Compared with PBDEs, concentrations of musks were significantly lower in breast milk than in serum and a little correlation in concentrations among the three human biological matrices were observed. The differences in the profiles of musks relative to PBDEs were due to different clearance rates between these two compounds. The average hazard quotients (HQs) for daily intake of PBDEs by infants via lactation were 0.62, 0.42, and 0.19 for BDE-47, BDE-99, and BDE-153, respectively.

Perfluorinated compounds in whole blood samples from infants, children, and adults in China.

Two hundred and forty five human blood (whole blood) samples from Chinese donors aged from 0 to 90 yrs were analyzed for 10 perfluorinated compounds (PFCs). Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) were the most abundant PFCs found in blood. The median concentration of PFOS was lower in nonadults (i.e., infants, toddlers, children, and adolescents) (2.52-5.55 ng/mL) than in adults (8.07 ng/mL). However, median concentration of PFOA in nonadults (1.23-2.42 ng/mL) was higher than that found in adults (1.01 ng/mL). A significant increase in PFOS (r = 0.468, p < 0.01) and perfluorohexane sulfonate (PFHxS) (r = 0.357, p < 0.01) concentrations with age was found, while PFOA concentrations (r = -0.344, p < 0.01) were negatively correlated with age. No significant gender-related differences in PFC concentrations were found across all ages. The composition profiles of PFCs, as identified by principal component analysis, varied for each age group; this suggested differences in sources and pathways of exposure to PFCs for different age groups. Based on the blood PFC concentration, we estimated the daily intake of PFOS by adults using a one-compartment toxicokinetic model. The modeled daily intake of PFOS agreed well with the calculated daily intake via diet and indoor dust (0.74 vs 1.19 ng/kg b.w. for males, 1.20 vs 1.15 ng/kg b.w. for females) suggesting that dietary intake and dust ingestion are the major exposure routes to PFOS exposure in China. This is the first comprehensive study on PFCs in human blood from infants, toddlers, children, and adolescents in China. The data are valuable for understanding the sources and pathways of human exposure to PFCs for different age groups.

Perfluorochemicals in meat, eggs and indoor dust in China: assessment of sources and pathways of human exposure to perfluorochemicals.

In this study, 10 perfluorochemicals (PFCs) were measured in meat, meat products, and eggs, and in indoor dust, collected in China. Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) were the most frequently detected PFCs in these samples. Mean concentrations of PFOS and PFOA in foodstuffs were in the range of 0.05-1.99 ng/g fresh wt and 0.06-12.5 ng/g fresh wt, respectively. The mean concentrations of PFOA, perfluoroheptanoic acid (PFHpA), and PFOS in indoor dust were 205, 14.0, and 4.86 ng/g, dry wt, respectively. The estimated daily intake of PFOS and PFOA from meat, meat products and eggs (EDI(meat&eggs)) ranged from 6.00 to 9.64 ng/d and from 254 to 576 ng/d, respectively, when the values below the limit of quantitation (LOQ) were assigned as 0, and from 8.80 to 15.0 ng/d and from 255 to 577 ng/d, respectively, when the values below the LOQ were set at 1/2LOQ. The EDI(meat&eggs) of PFOS and PFOA increased with increasing family income. The estimated daily intake of PFOS and PFOA through inhalation of dust (EDI(dust)) ranged from 0.23 to 0.31 ng/d and from 9.68 to 13.4 ng/d, respectively. The daily intakes of PFOS and PFOA from the consumption of meat, meat products, and eggs, and from dust ingestion, as calculated from our samples in this study, were compared with estimated daily intake of PFCs reported from the concentrations in drinking water, fish and seafood from China. Our calculations indicate that dietary sources (EDI(dietary)) account for the overwhelming proportion of (>99% for PFOS and 98% for PFOA) total daily intake (TDI) in adults. The analyzed foodstuffs (meat, meat products, and eggs) were not the major contributors to dietary exposure to PFOS, whereas, meat was the primary contributor to dietary exposure to PFOA.

Polybrominated diphenyl ether levels in foodstuffs collected from three locations from the United States.

OBJECTIVES: The objectives of this study were to provide updated measurements of PBDEs in US food, to estimate possible difference in levels from differing geographical regions, and to provide an improved estimate of current dietary intake. METHODS: Thirty matched food samples for a total of 90 samples were collected from each of three cities (Los Angeles, California; Dallas, Texas; and Albany, New York) and were analyzed for 13 polybrominated diphenyl ether congeners (BDE 28, 47, 49, 66, 85, 99, 100, 138, 153, 154, 183, 203, and 209). Dietary intake of PBDEs was estimated by food type, age, and sex. RESULTS: In this pilot study, we did not note a statistically significant difference in total PBDE levels in food collected from the three locations. The median total PBDE levels (estimating non-detected values as half of the detection limit) in meat, dairy, eggs, and fish were 267 pg/g wet weight (ww) (range 102-3156 pg/g ww), 176 pg/g ww (range 41-954 pg/g ww), 637 pg/g ww (range 193-932 pg/g ww), and 243 pg/g ww (range 36-2161 pg/g ww). PBDE intake from food was estimated to range from 2.7 ng/kg/day for children 2 through 5 years of age to 0.8 ng/kg/day for women aged 60 years and older. This compares closely with our previous study where the intake estimate was 2.7 ng/kg/day for children 2 through 5 years of age and 0.9 ng/kg/day for women aged 60 years and older. CONCLUSION: We did not find a decrease of PBDEs in food since our previous studies which we expected to find due to the declining use of PBDEs in the USA. These findings could be consistent with food contamination from depot sources of PBDEs. A larger, more representative sampling of the US food supply is indicated based on our findings.

Specific profiles of perfluorinated compounds in surface and drinking waters and accumulation in mussels, fish, and dolphins from southeastern Brazil.

Despite the concern over widespread distribution of perfluorinated compounds (PFCs) even in sparsely populated regions of the world, few studies have reported their occurrence in South America. In this study, PFCs were measured in Rio de Janeiro State in southeast Brazil: in drinking water from various districts in the State, in river water and tucuxi dolphins from the Paraiba do Sul River, several species of fish from the State, and mussels from Guanabara Bay. Liver, kidney, and muscle from fishes were analyzed to enable an understanding of the tissue distribution of PFCs. PFOS, PFOA, and PFHxS were detected in all drinking water samples in concentration ranges of 0.58-6.70, 0.35-2.82, and 0.15-1.00 ng L(-1), respectively. The profiles of PFCs in drinking water from Brazil (with PFOS concentrations comparable to or higher than those of PFOA) were different from the profiles that have been reported for other countries. In fish, concentrations of PFOS were, in general, higher in liver than in muscle. Concentrations of PFOA in livers of fish were similar to or lower than fish muscle tissue concentrations. PFOS and PFOA were found in brown mussels from Guanabara Bay. Bioconcentration factors (BCFs) of PFOA calculated for mussels were higher than the BCFs calculated for fishes. Elevated concentrations of PFUnDA (mean: 109+/-17.4 ng g(-1) wet weight) were found in mussels from certain locations within Guanabara Bay. Although PFCs were detected in all types of samples analyzed, the concentrations were generally lower than the concentrations reported for Japan and the USA.

Chlorinated, brominated, and perfluorinated compounds, polycyclic aromatic hydrocarbons and trace elements in livers of sea otters from California, Washington, and Alaska (USA), and Kamchatka (Russia).

Concentrations of organochlorine pesticides (DDTs, HCHs, and chlordanes), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), polycyclic aromatic hydrocarbons (PAHs), perfluorinated compounds (PFCs), and 20 trace elements were determined in livers of 3- to 5-year old stranded sea otters collected from the coastal waters of California, Washington, and Alaska (USA) and from Kamchatka (Russia). Concentrations of organochlorine pesticides, PCBs, and PBDEs were high in sea otters collected from the California coast. Concentrations of DDTs were 10-fold higher in California sea otters than in otters from other locations; PCB concentrations were 5-fold higher, and PBDE concentrations were 2-fold higher, in California sea otters than in otters from other locations. Concentrations of PAHs were higher in sea otters from Prince William Sound than in sea otters from other locations. Concentrations of several trace elements were elevated in sea otters collected from California and Prince William Sound. Elevated concentrations of Mn and Zn in sea otters from California and Prince William Sound were indicative of oxidative stress-related injuries in these two populations. Concentrations of all of the target compounds, including trace elements, that were analyzed in sea otters from Kamchatka were lower than those found from the US coastal locations.

Polybrominated diphenyl ethers and polybrominated biphenyls in sediment and floodplain soils of the Saginaw River watershed, Michigan, USA.

Despite known historical release of polybrominated biphenyls (PBBs; brominated flame retardants) into the Pine River (St. Louis, MI, USA), a tributary of the Tittabawassee River which subsequently forms the Saginaw River and flows into Saginaw Bay-Lake Huron, little is known about spatial patterns of sediment contamination by PBBs in this watershed. In this study, concentrations of two groups of brominated flame retardants, polybrominated diphenyl ethers (summation PBDE; BDE-28, -47, -66, -100, -99, -85, -154, -153, -138, and -209) and PBBs were measured in more than 120 floodplain soil samples, surface sediment samples, and sediment cores collected in 2004 from the Shiawassee River, the Saginaw River, and Saginaw Bay, Michigan. In addition, sediment samples collected in 2002 from the Pine River and the Tittabawassee River were analyzed, to elucidate riverine transport and attenuation of PBBs and PBDEs in this watershed. The mean concentration of summation PBDE decreased from upstream to downstream, from the Shiawassee River and the Tittabawassee River to Saginaw Bay. BDE-209 was the predominant congener, accounting for 79% of the total PBDE concentration in the Shiawassee River and 90% in the Saginaw River. BDE-209 was followed, in order of decreasing abundance, by BDE-47, -99, and -100. The proportions of BDE congeners varied by water body, and by sample type, whether floodplain soil or sediment. High summation PBDE concentrations were found in floodplain soil collected from the Shiawassee River near Chase Lake (55 ng/g, dry weight) and in sediment from the Saginaw River near Middleground Island (49 ng/g, dry weight). There was a significant positive correlation between summation (9)PBDE (tri- to hexa-BDE) and BDE-209 in samples collected from the Shiawassee River and Saginaw Bay, but not in samples from the Saginaw River. Among PBBs, bromobiphenyl congener 153 (BB-153) was found in sediments from the Saginaw River but not in sediments from the Shiawassee River. An elevated concentration of BB-153 (13.5 ng/g, dry weight) was found in floodplain soil collected from the Pine River. The BB-153 concentration in sediment decreased by two to three orders of magnitude, from the Pine River downstream to Saginaw Bay. An elevated concentration of BB-153 (4.7 ng/g) was found in sediment collected from the mouth of the Saginaw River. Surface sediments collected near the mouth of the Saginaw River contained higher concentrations of both PBDEs and PBBs than did the subsurface sediments at these locations.

Dioxin-like toxicity in the Saginaw River Watershed: polychlorinated dibenzo-p-dioxins, dibenzofurans, and biphenyls in sediments and floodplain soils from the Saginaw and Shiawassee Rivers and Saginaw Bay, Michigan, USA.

Sediment and floodplain soils in the Saginaw River Watershed, Michigan, USA, have been demonstrated to be contaminated with a variety of organic compounds, including polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs). Existing data indicate that, at some locations, the contamination exceeds human health risk-based regulatory levels and ecological risk-based screening levels. In this study, concentrations of PCBs including non-ortho coplanar congeners, PCDDs, and PCDFs were measured in more than 120 sediment and floodplain soil samples collected from the Shiawassee River (a tributary of the Saginaw River), the Saginaw River, and Saginaw Bay, to determine the sources and magnitude of contamination, and to elucidate the contributions from individual contaminant groups to the overall 2,3,7,8-tetrachlorodibezo-p-dioxin equivalents (TEQs). Sediment and soil extracts were also analyzed for total dioxin-like activity by means of the H4IIE-luc cell bioassay. Elevated concentrations of PCBs (>1000 ng/g, dry weight) were found in surface sediment and floodplain soil samples collected from the Shiawassee River near Chase Lake, from Middleground Island in the Saginaw River, and from subsurface sediments in Saginaw Bay. Concentrations of PCDDs and PCDFs in sediment and floodplain soils from the Saginaw River and Saginaw Bay were 2 to 3 orders of magnitude higher than concentrations in the samples from the Shiawassee River. The highest PCDD/F concentration (55,200 pg/g, dry weight in a subsurface layer) was found in sediment collected at the mouth of the Saginaw River. Concentrations of PCDFs were greater than the concentrations of PCDDs in sediment from the Saginaw River. 2,3,7,8-TCDF, 1,2,3,7,8-PeCDF, and 2,3,4,7,8-PeCDF were the major PCDF congeners found in sediments from the Saginaw River. The elevated concentrations of PCDFs, and the predominance of the less highly chlorinated PCDF congeners, in sediments from the Saginaw River were similar to previously determined characteristics of the PCDF contamination of the Tittabawassee River, another tributary of the Saginaw River. These results suggest the existence of a major source of PCDFs within the watershed. A few localized areas of high PCDD/F and PCB concentrations, with unique congener compositions, in the Saginaw River indicated the presence of other minor sources, such as wastewater treatment plants. PCDFs were the major contributors to TEQs in sediment and soils from the Saginaw River and Saginaw Bay. Approximately 30% of the samples analyzed in this study had values exceeding the screening level of 50 pg TEQ/g, dry wt, suggested for soils by the Agency for Toxic Substances and Disease Registry.

Chlorinated, brominated, and perfluorinated contaminants in livers of polar bears from Alaska.

The existence of two subpopulations of polar bears in Alaska, the Beaufort Sea and the Chukchi Sea populations, has been documented. In this study, differences in concentrations and profiles of organochlorine pesticides, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and perfluorinated acids were examined in livers of polar bears from the two subpopulations in Alaska. Concentrations of most of the organohalogens analyzed were greater in the Beaufort Sea subpopulation than in the Chukchi Sea subpopulation, except for HCHs and perfluorononanoic acid (PFNA), which were high in samples from the Chukchi Sea subpopulation. Concentrations of chlordanes, PCBs, and perfluorooctanesulfonate (PFOS) were significantly different between the two subpopulations. Chlordane was the predominant contaminant in the Beaufort Sea population, and PFOS was the major contaminant in the Chukchi Sea population. Polar bears from the Beaufort Sea showed significantly higher proportions of more highly chlorinated PCBs than those from the Chukchi Sea. Concentrations of several perfluorinated acids were significantly correlated. Overall, the concentrations and profiles of organohalogens analyzed in the two subpopulations of polar bears suggest differences in the sources of exposures between the two regions of Alaska.