Continuous exposure to dibromoacetic acid delays pubertal development and compromises sperm quality in the rat.

Previously our work on the haloacid by-products of drinking water disinfection focused on adult exposures. Herein we evaluate the consequence of continuous exposure to dibromoacetic acid (DBA) via drinking water through reproductive development into adulthood. An initial study in which offspring were exposed from gestation day (GD) 15 through adulthood revealed significant delays in preputial separation and vaginal opening, dose-related decreases in the fertility of cauda epididymal sperm, and dose-related diminutions in the sperm membrane protein SP22. Subsequent studies consisted of groups in which exposure ceased on postnatal day 21 (PND 21) versus adulthood. For each exposure, animals were evaluated after puberty (PND 56) as well as at adulthood (PND 120). Exposure to 4, 40, or 400 ppm DBA from GD 15 through PND 21 failed to result in any significant reproductive alterations. By contrast, continuous exposure until adulthood resulted in dose-related alterations consistent with those observed in the dose-finding study. Preputial separation and vaginal opening were delayed 4 and 3 days in males and females exposed to 400 ppm (76.3 mg/kg) DBA. This was associated with increased responsiveness of both the testis and ovary to hCG ex vivo; hCG-stimulated testosterone production by testicular parenchyma on PND 56 was increased at 4 ppm (0.6 mg/kg) DBA and higher. Finally, the quality of proximal cauda epididymal sperm was compromised by continuous exposure to DBA. The sperm membrane proteome was altered in a dose-related manner with SP22, and one of its charged variants, diminished at 40 ppm (3.6 mg/kg) DBA and higher. As more sensitive endpoints are evaluated, lower effect levels can be attributed to haloacid exposure. We are now extending our evaluations to epidemiology studies designed to evaluate sperm quality in men exposed to varying levels of disinfection by-products.     

Immunotoxicity of dibromoacetic acid administered via drinking water to female B6C3F1 mice

Dibromoacetic acid (DBA) is a disinfection by-product commonly found in drinking water as a result of chlorination/?ozonation processes. The Environmental Protection Agency estimates that more than 200 million people consume disinfected water in the United States. This study was conducted to evaluate the potential immunotoxicological effects of DBA exposure when administered for 28 days via drinking water to B₆C₃F₁ mice, at concentrations of 125, 500, and 1000?mg/L. Multiple endpoints were evaluated to assess innate, humoral, and cell-mediated immune components, as well as host resistance. Standard toxicological parameters were unaffected, with the exception of a dose–responsive increase in liver weight and a decrease in thymus weight at the two highest exposure levels. Splenocyte differentials were affected, although the effects were not dose–responsive. Exposure to DBA did not significantly affect humoral immunity (immunoglobulin M [IgM] plaque assay and serum IgM anti-sheep erythrocyte titers) or cell-mediated immunity (mixed-leukocyte response). No effects were observed on innate immune function in either interferon-γ-induced in vitro macrophage cytotoxic activity or basal natural killer (NK)-cell activity. Augmented NK-cell activity (following exposure to polyinosinic-polycytidylic acid) was decreased at the low dose, however the effect was not dose–responsive. Finally, DBA exposure had no effect on resistance to infection with either Streptococcus pneumoniae or Plasmodium yoelii, or challenge with B16F10 melanoma cells. With the exception of changes in thymus weight, these results indicate that DBA exposure resulted in no immunotoxic effects at concentrations much larger than those considered acceptable in human drinking water.     

Physicochemical and functional properties of micronized jincheng orange by-products (Citrus sinensis Osbeck) dietary fiber and its application as a fat replacer in yogurt

Orange by-products from juice extraction are generally discarded or used in animal feed due to their low market value. However, orange by-products show potential as dietary fiber (DF) and fat replacers in products such as yogurt. This study assessed the benefits of using orange by-products in DF-enriched materials such as DF powders (OP) and micronized DF with ball-milling (MDF). The study also investigated the effects of adding different levels of OP and MDF on the quality of low-fat yogurt. Results show that MDF showed better physicochemical and functional properties than OP, and that 2% MDF as a fat replacer in yogurt retained most of the textural and sensory properties of full-fat yogurt. Therefore, this study showed that MDF is a promising alternative as a fat replacer in low-fat yogurt, without sacrificing good taste and other qualities of full-fat yogurt.     

Health effects of exposure to chlorination by-products in swimming pools

Concerns have been raised regarding the potential negative effects on human health of water disinfectants used in swimming pools. Among the disinfection options, the approaches using chlorine-based products have been typically preferred. Chlorine readily reacts with natural organic matter that are introduced in the water mainly through the bathers, leading to the formation of potentially harmful chlorination by-products (CBPs). The formation of CBPs is of particular concern since some have been epidemiologically associated with the development of various clinical manifestations. The higher the concentration of volatile CBPs in the water, the higher their concentration in the air above the pool, and different routes of exposure to chemicals in swimming pools (water ingestion, skin absorption, and inhalation) contribute to the individual exposome. Some CBPs may affect the respiratory and skin health of those who stay indoor for long periods, such as swimming instructors, pool staff, and competitive swimmers. Whether those who use chlorinated pools as customers, particularly children, may also be affected has been a matter of debate. In this article, we discuss the current evidence regarding the health effects of both acute and chronic exposures in different populations (work-related exposures, intensive sports, and recreational attendance) and identify the main recommendations and unmet needs for research in this area.     

小体积水样测定饮用水中二氯乙酸、三氯乙酸的含量

目的优化生活饮用水标准检验方法,建立利用小体积水测定生活饮用水中微量二氯乙酸（DCAA）、三氯乙酸（TCAA）的气相色谱测定方法。方法饮用水中DCAA、TCAA经过酸化、萃取、衍生后,采用气相色谱电子捕获检测器定量检测。结果 DCAA、TCAA在谱图上能够很好的分离,相关系数均大于0.999 5,回收率为94.5%-109.1%,RSD为3.1%-6.5%。结论该方法快速,准确,灵敏度高,适用于生活饮用水的常规批量检测。     

肢芽细胞微团培养评价饮水中有机物致畸性

目的应用大鼠肢芽细胞微团培养技术快速评价饮用水中有机物的致畸性,并比较氯化消毒过程对致畸作用的影响。方法XAD-4树脂富集、浓缩饮用水中有机物,连续5 d微团培养d13大鼠肢芽细胞,根据半数分化抑制浓度(ID50)和半数增殖抑制浓度(IP50)及IP50/ID50比值判定有机浓集物的致畸性。结果在较低剂量范围内,管网末梢水中有机物对大鼠肢芽细胞的分化有明显的抑制作用,ID50分别为363.1 ml/ml(-S9)和5.67 ml/ml( S9);IP50分别为1355.2 ml/ml(-S9)和1264.5 ml/ml( S9),IP50/ID50=3.7(-S9);IP50/ID50=223( S9),显示该组分特异性抑制肢芽细胞的分化,经代谢转化后其ID50降低达63倍;原水中有机浓集物的ID50分别为1.17 ml/ml(-S9)和0.387 ml/ml( S9);IP50分别为15.8 ml/ml(-S9)和41.1 ml/ml( S9);IP50/ID50=13.5(-S9);IP50/ID50=106.2( S9),代谢活化增加该组分的抑制分化作用。结论管网末梢水及原水中有机浓集物属特异性细胞分化抑制物,具有潜在的直接和间接致畸性,为潜在的强致畸原,显示多种致畸机制。氯化消毒过程可能增加饮用水中有机物的间接致畸作用。     

Combination of Extrusion and Fermentation with Lactobacillus plantarum and L. uvarum Strains for Improving the Safety Characteristics of Wheat Bran

Processed wheat bran (W) is of great importance for food and feed. Consequently, the biosafety of W should be evaluated and improved with valorisation strategies. This study tested a design combining extrusion (at temperature of 115 and 130 °C; screw speeds of 16, 20, and 25 rpm) and fermentation with Lactobacillus plantarum and L. uvarum strains for the valorisation of W to provide safer food and feed stock. The influence of different treatments on biogenic amine formation, mycotoxin content, and free amino acids, as well as acidity, microbiological parameters, and sugar concentration, were analysed. This research showed that a combination of extrusion and fermentation with selected strains can change several aspects of W characteristics. There was a significant effect of applied treatments on acidity and the microbiological parameters of W, as well as biogenic amines content. The lowest total mycotoxin concentration (29.8 µg/kg) was found in extruded (130 °C; 25 rpm) and fermented with L. uvarum sample. Finally, the combination of the abovementioned treatments can be confirmed as a prospective innovative pre-treatment for W, capable of potentially enhancing their safety characteristics and composition.     

Chloroacetonitrile induces oxidative stress and apoptosis in mouse fetal liver

Chloroacetonitrile (CAN) is a disinfection by-product of chlorination of drinking water. The present study was designed to investigate the potential adverse effects of maternal exposure to CAN on fetal liver in mice. Based on an initial dose–response experiment, CAN (25 mg/(kg day)) was given orally to pregnant mice at gestation day (GD) 6, till GD 18. Fetuses were collected and fetal livers were used for assessing oxidative status, apoptosis and histopathological changes. Maternal exposure to CAN resulted in observed oxidative stress and redox imbalance in fetal liver tissues as marked by significant decrease in reduced glutathione (GSH) and elevation of oxidized glutathione (GSSG), malondialdehyde (MDA) and 8-hydroxy-2′-deoxyguanosine (8-OHdG) in genomic DNA. Further, CAN induced apoptosis as indicated by a significant increase in binding of Hoechst reagent to damaged DNA fragments of fetal liver and enhancement of the activity of caspase-3 in cytosolic fractions of fetal livers. Histopathological examination of fetal livers of CAN-treated mice showed hepatocytes with vacuolated cytoplasm, karyolysis and karyorrhexis as well as depletion of their glycogen content. In conclusion, maternal exposure to CAN adversely affects mouse fetal livers as evidenced by the induction of oxidative stress, apoptosis and histopathological changes.     

Bromochloroacetic acid exerts qualitative effects on rat sperm: implications for a novel biomarker.

Disubstituted haloacid by-products of drinking water disinfection such as dibromoacetic acid and dichloroacetic acid have been shown to perturb spermatogenesis and fertility in adult male rats. In the present study we sought to establish whether equimolar exposure to bromochloroacetic acid (BCA), a prevalent by-product in finished drinking water, is also capable of disrupting these endpoints, and if so to determine whether the novel biomarker of fertility (SP22) would be correlated with subfertility induced by testicular toxicity. A dose range finding study indicated that body weight was not affected by exposure to 14 daily doses of 72 mg/kg BCA while numerous male reproductive parameters were altered, including decreases in the number and progressive motility of cauda epididymal sperm. In addition, there was an increased incidence of delayed spermiation in the testes of males exposed to 72 mg/kg BCA. In the definitive study, exposures ranged from 8 to 72 mg/kg, the fertility of cauda epididymal sperm was evaluated by in utero insemination, and the two-dimensional profile of cauda sperm membrane proteins was evaluated quantitatively. The morphology of both caput and cauda epididymal sperm was altered by 72 mg/kg BCA. The fertility of cauda epididymal sperm, the percentages of progressively motile sperm and progressive tracks, and two sperm membrane proteins (SP22 and SP9) were decreased significantly by each BCA exposure. While the two sperm proteins and the two measures of progressive motility were each significantly correlated with fertility, only one of these measures (i.e., SP22) had an r value of greater than 0.5. When data for SP22 and fertility were fit to a nonlinear model, r(2) was 0.84. Using this exposure paradigm, the no-observed-effect level for BCA is less than 8 mg/kg. Moreover, SP22 may be useful in predicting compromised fertility after exposure to by-products of drinking water disinfection.     

Childhood Asthma and Environmental Exposures at Swimming Pools: State of the Science and Research Recommendations

Objectives

Recent studies have explored the potential for swimming pool disinfection by-products (DBPs), which are respiratory irritants, to cause asthma in young children. Here we describe the state of the science on methods for understanding children’s exposure to DBPs and biologics at swimming pools and associations with new-onset childhood asthma and recommend a research agenda to improve our understanding of this issue.

Data sources

A workshop was held in Leuven, Belgium, 21–23 August 2007, to evaluate the literature and to develop a research agenda to better understand children’s exposures in the swimming pool environment and their potential associations with new-onset asthma. Participants, including clinicians, epidemiologists, exposure scientists, pool operations experts, and chemists, reviewed the literature, prepared background summaries, and held extensive discussions on the relevant published studies, knowledge of asthma characterization and exposures at swimming pools, and epidemiologic study designs.

Synthesis

Childhood swimming and new-onset childhood asthma have clear implications for public health. If attendance at indoor pools increases risk of childhood asthma, then concerns are warranted and action is necessary. If there is no such relationship, these concerns could unnecessarily deter children from indoor swimming and/or compromise water disinfection.

Conclusions

Current evidence of an association between childhood swimming and new-onset asthma is suggestive but not conclusive. Important data gaps need to be filled, particularly in exposure assessment and characterization of asthma in the very young. Participants recommended that additional evaluations using a multidisciplinary approach are needed to determine whether a clear association exists.