Perchlorate and iodide in dairy and breast milk

Perchlorate inhibits iodide uptake and may impair thyroid and neurodevelopment in infants. Recently, we unambiguously identified the presence of perchlorate in all seven brands of dairy milk randomly purchased from grocery stores in Lubbock, TX. How widespread is perchlorate in milk? Perchlorate in 47 dairy milk samples from 11 states and in 36 human milk samples from 18 states were measured. Iodide was also measured in a number of the samples. Perchlorate was detectable in 81 of 82 samples. The dairy and breast milk means were, respectively, 2.0 and 10.5 microg/L with the corresponding maximum values of 11 and 92 microg/L. Perchlorate is present in virtually all milk samples, the average concentration in breast milk is five times higher than in dairy milk. Although the number of available measurements are few at this point, for breast milk samples with a perchlorate content greater than 10 microg/L, the iodide content is linearly correlated with the inverse of the perchlorate concentration with a r2 of >0.9 (n = 6). The presence of perchlorate in the milk lowers the iodide content and may impair thyroid development in infants. On the basis of limited available data, iodide levels in breast milk may be significantly lower than it was two decades ago. Recommended iodine intake by pregnant and lactating women may need to be revised upward.     

Perchlorate uptake in spinach as related to perchlorate, nitrate, and chloride concentrations in irrigation water

Several studies have reported on the detection of perchlorate (ClO(4)(-)) in edible leafy vegetables irrigated with Colorado River water. However, there is no information on spinach as related to ClO(4)(-) in irrigation water nor on the effect of other anions on ClO(4)(-) uptake. A greenhouse ClO(4)(-) uptake experiment using spinach was conducted to investigate the impact of presence of chloride (Cl(-)) and nitrate (NO(3)(-)) on ClO(4)(-) uptake under controlled conditions. We examined three concentrations of ClO(4)(-), 40, 220, and 400 nmol(c)/L (nanomoles of charge per liter of solution), three concentrations of Cl(-), 2.5, 13.75, and 25 mmol(c)/L, and NO(3)(-) at 2, 11, and 20 mmol(c)/L. The results revealed that ClO(4)(-) was taken up the most when NO(3)(-) and Cl(-) were lowest in concentration in irrigation water. More ClO(4)(-) was detected in spinach leaves than that in the root tissue. Relative to lettuces, spinach accumulated more ClO(4)(-) in the plant tissue. Perchlorate was accumulated in spinach leaves more than reported for outer leaves of lettuce at 40 nmol(c)/L of ClO(4)(-) in irrigation water. The results also provided evidence that spinach selectively took up ClO(4)(-) relative to Cl(-). We developed a predictive model to describe the ClO(4)(-) concentration in spinach as related to the Cl(-), NO(3)(-), and ClO(4)(-) concentration in irrigation water.     

Effect of fluid intake on skin physiology: distinct differences between drinking mineral water and tap water

It is generally stated that drinking plenty of water has a positive influence on skin condition. However, there is no published scientific study that has investigated this matter. The aim of our exploratory 'before-after' study was to evaluate the in vivo influence of drinking more than 2 L of mineral water or ordinary tap water per day on skin physiology. Ninety-three healthy subjects were included in our prospective study. After an initial run-in phase of 2 weeks to monitor individual drinking habits, subjects had to drink 2.25 L day(-1) of either mineral water (n = 53) or tap water (n = 40) for 4 weeks. Bioengineering in vivo measurements on the volar forearm included sonographic evaluation of skin thickness and density, determination of skin surface pH, assessment of skin surface morphology, and measurement of finger circumference. Eighty-six subjects completed the study. In the mineral water group measurements revealed a statistically significant decrease in skin density. Skin thickness increased slightly, albeit not at a statistically significant level. However, when separately analysing those individuals from the mineral water group, who had routinely drunken comparably little before the start of the study, their skin thickness increased at a statistically significant level. Skin surface pH remained almost unchanged in the physiologically optimal range. In the tap water group, skin density increased significantly, while skin thickness decreased significantly. Skin surface pH decreased at a statistically significant level. While in the mineral water group finger circumference decreased significantly, measurements in the tap water group revealed a statistically significant increase. Objective skin surface morphology did not change in any group. In summary, drinking more than 2 L of water per day can have a significant impact on skin physiology. The exact effects within the skin seem to differ depending on the nature of the water ingested. Randomized, controlled, double-blind follow-up trials are warranted to confirm the findings of our exploratory pilot study.     

Perchlorate and nitrate in leafy vegetables of North America

In previous studies trace levels of perchlorate were found in lettuce (Lactuca sativa L.) irrigated with Colorado River water, which is contaminated with low levels of perchlorate from aerospace and defense related industries. In this paper, we report the results of a survey conducted across North America to evaluate the occurrence of perchlorate in leafy vegetables produced outside the lower Colorado River region, and evaluate the relative iodide uptake inhibition potential to perchlorate and nitrate in these leafy vegetables. Conventionally and organically produced lettuce and other leafy vegetable samples were collected from production fields and farmers' markets in the central and coastal valleys of California, New Mexico, Colorado, Michigan, Ohio, New York, Quebec, and New Jersey. Results show that 16% of the conventionally produced samples and 32% of the organically produced samples had quantifiable levels of perchlorate using ion chromatography. Estimated perchlorate exposure from organically produced leafy vegetables was approximately 2 times that of conventional produce, but generally less than 10% of the reference dose recommended by the National Academy of Sciences. Furthermore, the iodide uptake inhibition potential of perchlorate was less than 1% of that of the nitrate present. These data are consistent with those of other reported perchlorate survey work with lettuce, bottled water, breast milk, dairy milk, and human urine, and suggest a wide national presence of perchlorate.     

Comparison of trihalomethanes in tap water and blood

Trihalomethane (THM) concentrations in blood and tap water were measured for 50 women living in two locations with different bromide concentrations and disinfectant types. Blood samples were taken from each woman early in the morning prior to any major water-use activity and again immediately after showering. Each residence was sampled for THMs in tap water prior to the woman's shower. Cobb County, GA, tap water exhibited high THM concentrations composed primarily of chloroform. Corpus Christi, TX, tap water exhibited lower THM concentrations with significant proportions of brominated THMs. THMs in tap water and blood were compared using mole fraction speciation, extent of bromine incorporation, and correlation analysis. Results indicated that THMs in the blood rose significantly as a result of showering, that showering shifted the THM distribution in the blood toward that found in the corresponding tap water, and that THMs measured in the blood of women living in the two locations reflected species and concentration differences in their respective tap waters. In general, blood concentrations were not significantly correlated with tap water concentrations. This finding suggests that other factors, in addition to tap water concentrations, may be important in determining THM concentrations in the blood.     

造纸工业的排水、取水和节水

从国家标准“造纸工业水污染物排放标准”的制订及几次修改和国家标准“造纸产品取水定额”的制定，来分析对造纸工业排水、取水的认识。从制浆系统和抄纸系统论述了造纸工业节水的技术措施，尤其是对封闭循环和“零排放”的可能性、存在问题和解决措施进行了探讨。     

Estimated dietary intake of nitrite and nitrate in Swedish children

This study examines the intake of nitrate and nitrite in Swedish children. Daily intake estimates were based on a nationwide food consumption survey (4-day food diary) and nitrite/nitrate content in various foodstuffs. The mean intake of nitrite from cured meat among 2259 children studied was 0.013, 0.010 and 0.007 mg kg(-1) body weight day(-1) in age groups 4, 8-9 and 11-12 years, respectively. Among these age groups, three individuals (0.1% of the studied children) exceeded the acceptable daily intake (ADI) of 0.07 mg nitrite kg(-1) body weight day(-1). The mean intake of nitrate from vegetables, fruit, cured meat and water was 0.84, 0.68 and 0.45 mg kg(-1) body weight day(-1) for children aged 4, 8-9 and 11-12 years, respectively. No individual exceeded the ADI of 3.7 mg nitrate kg(-1) body weight day(-1). However, when the total nitrite intake was estimated, including an estimated 5% endogenous conversion of nitrate to nitrite, approximately 12% of the 4-year-old children exceeded the nitrite ADI. Thus, the intake of nitrite in Swedish children may be a concern for young age groups when endogenous nitrite conversion is included in the intake estimates.     

Estimated dietary intake of nitrite and nitrate in Swedish children

This study examines the intake of nitrate and nitrite in Swedish children. Daily intake estimates were based on a nationwide food consumption survey (4-day food diary) and nitrite/nitrate content in various foodstuffs. The mean intake of nitrite from cured meat among 2259 children studied was 0.013, 0.010 and 0.007?mg?kg^?1?body?weight?day^?1 in age groups 4, 8–9 and 11–12 years, respectively. Among these age groups, three individuals (0.1% of the studied children) exceeded the acceptable daily intake (ADI) of 0.07?mg?nitrite?kg^?1 body weight?day^?1. The mean intake of nitrate from vegetables, fruit, cured meat and water was 0.84, 0.68 and 0.45?mg?kg^?1 body weight?day^?1 for children aged 4, 8–9 and 11–12 years, respectively. No individual exceeded the ADI of 3.7?mg?nitrate?kg^?1 body weight?day^?1. However, when the total nitrite intake was estimated, including an estimated 5% endogenous conversion of nitrate to nitrite, approximately 12% of the 4-year-old children exceeded the nitrite ADI. Thus, the intake of nitrite in Swedish children may be a concern for young age groups when endogenous nitrite conversion is included in the intake estimates.     

原子吸收法快速检测自来水中铅、铬、镉的含量

目的建立一种快速、准确测定自来水中铅、铬、镉含量的石墨炉原子吸收法。方法样品硝酸浓度为1%,基体改进剂为10 g/L磷酸二氢铵,配制铅、铬、镉混合标准溶液,仪器固定体积自动配置曲线,采用外标法定量。结果该检测方法回收率范围:铅95.2%~106.0%,铬95.8%~102.4%,镉94.7%~110.7%;相对标准偏差(relative standard deviation,RSD)范围:铅0.91%~1.33%,铬0.81%~2.07%,镉0.98%~4.45%;检出限:铅0.1μg/L,铬0.1μg/L,镉0.03μg/L;定量限:铅0.3μg/L,铬0.3μg/L,镉0.09μg/L。结论该方法快速、准确、重复性好,可用于自来水中重金属铅、铬、镉的检测。     

Evaluation of silicon intake through consumption of Takju,Soju, and wine

The protective activities of 6 different catechins on the singlet oxygen induced photooxidation of α-terpinene in methanol were studied to find out the relation between their structure and singlet oxygen quenching activity. The total singlet oxygen quenching abilities (k _r +k _q values) in the same system were also calculated by using a Stern-Volmer plot. The protective activities were in order of epigallocatechin gallate (EGCG)=epigallocatechin (EGC) > gallocatechin gallate (GCG) > epicatechin gallate (ECG) > epicatechin (EC) > catechin (C). The k _r +k _q values of EGCG and C were 1.31×10⁸ and 1.66×10⁷/M·s, respectively. The pyrogallol (B) ring structure was the most influencing factor for the k _r +k _q values. Stereospecific configuration also provided a considerable influence on the values. The G-ring structure did not show significant influence in the value for EGCG and EGC. The k _r values of the catechins were 3.23×10⁵–1.64×10⁶/M·s.     

Pb particles from tap water: bioaccessibility and contribution to child exposure

High particulate lead (Pb) levels can be measured in tap water, but the hazard linked to particulate Pb ingestion is unknown. An in vitro test was developed to determine the bioaccessibility of Pb particles from tap water, based on the Relative Bioaccessibility Leaching Procedure validated for soils, and applied to lab-generated particles and field particles collected behind the aerator tap. Field particles were found in 43% of the 342 taps investigated equipped with an aerator, and contained significant amounts of Pb (0.003-71%, median 4.7%). The bioaccessibility of lab-generated particles ranged from 2 to 96% depending on the particle type (Pb(II) > Brass > Pb(IV) > solder), while that of field particles was distributed between 1.5 and 100% (median 41%). The hazard of particulate Pb ingestion depends on the amount and concentration ingested, and the bioaccessibility of the particulate Pb forms involved. Using the Integrated Exposure Uptake Biokinetic model, the impact of particulate Pb on the exposure of children aged 0.5-7 for the distribution system studied was the most significant when considering a fraction of the exposure from large buildings.     

A non-diazotization-coupling reaction-based colorimetric determination of nitrite in tap water and milk

A non-diazotization-coupling reaction-based colorimetric method was developed and validated for the determination of nitrite in tap water and milk samples. Under acidic condition, nitrite could selectively react with pyrrole, resulting in the emerging of a new absorption peak at 509 nm and a distinct color change from clear to red, with which the concentration of nitrite can be determined indirectly. Excellent linear range was achieved from 0.72 to 40.0 μmol L^?1 with a detection limit of 0.22 μmol L^?1. The detection limit was lower than or comparable to most of the recently published methods. The experimental conditions were optimized, and effects of coexisting substances were evaluated, and the results showed excellent priority since a certain amount of other anions, including SO₃ ^?, SeO₃ ^? and other acid radicals, would not interfere with the measurement. We highlighted the simplicity and efficiency of this method as no diazotization-coupling procedure and toxic aniline were involved. Determination of nitrite in tap water and milk samples was performed.     

自来水中余氯和亚硝酸盐含量与加热条件的相关性研究

目的研究自来水在不同加热方式下余氯及亚硝酸盐含量的变化,为人们日常健康饮水提供理论依据。方法根据国家标准GB 5750.5-2006和GB 5750.11-2006,对管网末梢水在经过不同煮沸时间、不同煮沸次数、煮沸后不同放置时间以及自动开水器及家用电水煲烧开的水中的余氯和亚硝酸盐含量进行检测。结果市政自来水中余氯含量为0.25 mg/L,亚硝酸盐含量未检出。自来水在煮沸1 min之后余氯含量未检出,而用家用电水煲烧开的水中余氯为0.1 mg/L,煮沸1 h,含量达到3.80μg/L,在国家标准限值之下。开水放置24 h亚硝酸盐含量达2.37μg/L,继续加热1 min后,含量再次升高达2.76μg/L。自来水反复煮沸8次后,亚硝酸盐含量达3.38μg/L。自动开水器烧开的自来水中余氯上午偏高,早上和晚上则未检出;亚硝酸盐含量在上午和晚上偏低,在早上含量明显升高。结论市政自来水通过加热,较高的余氯迅速挥发减少,而亚硝酸盐含量则会增加。家用电水煲开水中余氯残留较多,在使用家用电水煲时,建议电水煲断电后再开盖烧1 min。取公共场所自动开水器的水时,尽量避免在用水高峰时取水。     

Automatic milking and grazing--effects of location of drinking water on water intake, milk yield, and cow behavior

In an automatic milking system with cows grazing on a mixed grass sward, experiments were performed in 2001 and 2003, lasting 10 and 7 wk, respectively. Two location strategies for offering drinking water were compared: available in the barn and in the field (group B+F) or only in the barn (group B). During 2001, cows grazed alternately at 2 pastures at different distances from the barn, 50 m (near pasture) or 330 m (distant pasture), whereas the distant pasture was mainly used in 2003. No significant differences in milk yield, milking frequency, or milk composition were found between the 2 treatments. Average milk yield in the 2 experiments was 26.8 and 27.6 kg of milk in 2001 and 2003, respectively, and average milking frequency was 2.4 milkings/ d. Significant differences in animal behavior were observed only during the period when animals grazed on the distant pasture in 2001, with animals in group B+F spending 40% of their time on pasture and 21% of their time grazing, whereas corresponding values for group B were 34 and 17%, respectively. In 2003, average drinking water intakes per cow were 53 L/d on treatment B and 51 L/d on treatment B+F, and were not significantly different. Total daily water intake including water in the pasture was approximately 90 L/cow. In conclusion, no significant differences in milk yield, milking frequency, or water intake were found between cows offered drinking water both in the barn and in the field compared with drinking water only in the barn at pasture distances up to 330 m.