Hydrogen fluoride and inorganic fluorine compounds (fluorides) – Addendum: Evaluation of a pregnancy risk group for the BAT value

In 2005, the German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area re-evaluated the maximum workplace concentration (MAK value) of hydrogen fluoride [7664-39-3] and fluorides [16984-48-8]. If the MAK values of 1 ml hydrogen fluoride/m3 (0.83 mg/m3) or 1 mg fluoride/m3, respectively, are not exceeded, prenatal toxic effects are not to be expected. Therefore, hydrogen fluoride and fluorides were classified in Pregnancy Risk Group C. In 2013, the biological tolerance value (BAT value) for hydrogen fluoride and inorganic fluorine compounds (fluorides) of 4 mg fluoride/l urine was established which protects against the long-term effects of fluoride such as skeletal fluorosis. The BAT value was not derived in correlation to the MAK value. For this reason, it is to be evaluated whether no prenatal toxic effects are to be expected when the BAT value is adhered to. By extrapolating the NOAEL (no observed adverse effect level) for developmental toxicity in rodent studies to fluoride concentrations in urine it could be concluded that Pregnancy Risk Group C is also valid for the BAT value

The effect of a regional increase in ocean surface roughness on the tropospheric circulation: a GCM experiment

The sensitivity of the atmospheric circulation to an increase in ocean surface roughness in the Southern Hemisphere storm track is investigated in a paired general circulation model experiment. Such a change in sea roughness could be induced by ocean waves generated by storms. Two extended permanent-July runs are made. One with standard sea surface roughness, the other with ten times as a large surface roughness over open sea poleward of 40-degrees-S. The regional increase in ocean surface roughness significantly modifies the tropospheric circulation in the Southern Hemisphere. The strongest effect is the reduction of tropospheric winds (by 2 m/s or 100%) above the area with increased roughness. The poleward eddy momentum flux is reduced in the upper troposphere and the meridional eddy sensible heat flux is reduced in the lower troposphere. Zonal mean and eddy kinetic energy are consistently reduced

Isopropylbenzene – Addendum: evaluation of a pregnancy risk group for the BAT value

In 2012, the German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area re-evaluated the maximum workplace concentration (MAK value) of isopropylbenzene (cumene) [98-82-8]. If the MAK value of 10 ml iso-propylbenzene/m3 (50 mg/m3) is observed, no prenatal toxic effects are to be expected. Therefore, Pregnancy Risk Group C was confirmed. In 2013, the biological tolerance value (BAT value) of 10 mg 2-phenyl-2-propanol (after hydrolysis)/g creatinine was derived in correlation to the MAK value. Pregnancy Risk Group C is also similarly valid for the BAT value. In adherence with the BAT value of 10 mg 2-phenyl-2-propanol (after hydrolysis)/g creatinine, no prenatal toxic effects are to be expected

2-Propanol – Addendum: evaluation of a pregnancy risk group for the BAT value

In 2018, the German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area re-evaluated and confirmed the maximum workplace concentration (MAK value) of 2-propanol [67-63-0]. If the MAK value of 200 ml 2-propanol/m3 (500 mg/m3) is observed, no prenatal toxic effects are to be expected. Therefore, Pregnancy Risk Group C was likewise confirmed. In 2010, biological tolerance values (BAT values) of 25 mg acetone/l blood and 25 mg acetone/l urine were derived in correlation to the MAK value. Pregnancy Risk Group C is therefore similarly valid for the BAT value. In adherence with the BAT values of 25 mg acetone/l blood and 25 mg acetone/l urine, no prenatal toxic effects are to be expecte

1,2-Epoxypropane – Addendum: evaluation of a pregnancy risk group for the BAT value

In 2012, the German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area re-evaluated the maximum workplace concentration (MAK value) of 1,2-epoxypropane (propylene oxide) [75-56-9]. If the MAK value of 2 ml 1,2-epoxypropane/m3 (4.8 mg/m3) is observed, no prenatal toxic effects are to be expect ed. 1,2-epoxypropane was therefore classified in Pregnancy Risk Group C. In 2014, the biological tolerance value (BAT value) of 2500 pmol N-(2-hydroxypropyl)valine/g globin was derived in correlation to the MAK value. As a result, Pregnancy Risk Group C is likewise valid for the BAT value. No prenatal toxic effects are to be expected by compliance with the BAT value of 2500 pg N-(2-hydroxypropyl)valine/g globi

Dichloromethane – Addendum: evaluation of a pregnancy risk group for the BAT value

In 2014, the German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area re-evaluated the maximum workplace concentration (MAK value) of dichloromethane [75-09-2] and set a MAK value of 50 ml dichloromethane/m3 (180 mg/m3). In humans, exposure to 50 ml/m3 of dichloromethane led to CO-Hb levels in the range of 3%, which is above the endogenous CO-Hb range of 0.4–2.6% in non-smoking pregnant women. There is no information available on the CO-Hb level at which oxygen deficiency occurs in the foetal tissues. As a result, the possibility of prenatal toxicity cannot be excluded even if the MAK value of 50 ml dichloromethane/m3 is observed. Based on thisfinding, classification in Pregnancy Risk Group B has been confirmed. In 2015, the biological tolerance value (BAT value) of 500 μg dichloromethane/l blood was derived in correlation to the MAK value. Pregnancy Risk Group B istherefore also valid forthe BAT value. The possibility of prenatal toxicity cannot be excluded even when adhering to the BAT value of 500 μg dichloromethane/l bloo

Ethylbenzene – Addendum: evaluation of a pregnancy risk group for the BAT value

In 2011, the German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area re-evaluated the maximum workplace concentration (MAK value) of ethylbenzene [100-41-4]. If the MAK value of 20 ml ethylbenzene/m3 (88 mg/m3) is observed, no prenatal toxic effects are to be expected. Therefore, ethylbenzene was classified in Pregnancy Risk Group C. In 2015, the biological tolerance value (BAT value) of 250 mg mandelic acid plus phenylglyoxylic acid/g creatinine was derived in correlation to the MAK value. Pregnancy Risk Group C is therefore similarly valid for the BAT value. In adherence with the BAT value of 250 mg mandelic acid plus phenylglyoxylic acid/g creatinine, no prenatal toxic effects are to be expected

Numerical experiments on the atmospheric response to cold equatorial Pacific conditions ("La Nina") during northern summer

The effect of cold conditions in the central and eastern Equatorial Pacific during Northern Summer is examined in a series of numerical experiments with the low resolution (T21) atmospheric general circulation model ECHAM2. Anomalous sea surface temperatures (SST) as observed in June 1988 were prescribed and the effect on the global circulation is examined. In the model atmosphere, the anomalous cold water in the Equatorial Pacific excites a strong and stable response over the tropical Central and East Pacific. From here stationary Rossby waves radiate into both hemispheres. The Northern Hemisphere wave train is weak and affects only the Northeast Pacific area; the Southern Hemisphere wave train arches from the Central Pacific over the southern tip of South America to the South Atlantic. This response is not only present in the basic anomaly experiment with the T21 GCM but also in experiments with SST anomalies confined to the tropics and with an envelope- forrnulation of the SST anomalies, in experiments with a linear model, and in high resolution (T42) model experiments. The model output is also compared to the actually observed atmospheric state in June 1988. The model simulations do not reproduce the global circulation anomalies which were observed in June 1988. The model experiments are inconclusive with respect to the question of whether the North American drought observed in summer 1988 was related to the anomalous SST conditions in the Subtropical and Tropical Pacific. An explanatory analysis with a linear model reacting to prescribed heating anomalies as well as with the high-resolution GCM indicates that the model overreacted to the equatorial SST anomalies but almost ignored the contemporaneous subtropical SST anomalies on the Southern Hemisphere

Fluorwasserstoff und anorganische Fluorverbindungen (Fluoride) – Addendum: Evaluierung einer Schwangerschaftsgruppe zum BAT-Wert

In 2005, the German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area re-evaluated the maximum workplace concentration (MAK value) of hydrogen fluoride [7664-39-3] and fluorides [16984-48-8]. If the MAK values of 1 ml hydrogen fluoride/m3 (0.83 mg/m3) or 1 mg fluoride/m3, respectively, are not exceeded, prenatal toxic effects are not to be expected. Therefore, hydrogen fluoride and fluorides were classified in Pregnancy Risk Group C. In 2013, the biological tolerance value (BAT value) for hydrogen fluoride and inorganic fluorine compounds (fluorides) of 4 mg fluoride/l urine was established which protects against the long-term effects of fluoride such as skeletal fluorosis. The BAT value was not derived in correlation to the MAK value. For this reason, it is to be evaluated whether no prenatal toxic effects are to be expected when the BAT value is adhered to. By extrapolating the NOAEL (no observed adverse effect level) for developmental toxicity in rodent studies to fluoride concentrations in urine it could be concluded that Pregnancy Risk Group C is also valid for the BAT value