Association of blood lead and mercury with estimated GFR in herbalists after the ban of herbs containing aristolochic acids in Taiwan.

OBJECTIVE: This study was undertaken to explore the association of estimated glomerular filtration rate (GFR) with exposure to aristolochic acids (ALAs) and nephrotoxic metals in herbalists after the ban of herbs containing ALAs in Taiwan. METHODS: This cross-sectional study recruited a total of 138 herbalists without end-stage renal disease or urothelial carcinoma from the Occupational Union of Chinese Herbalists in Taiwan in 2007. Aristolochic acid I (ALA-I) was measured by ultra-high-pressure liquid chromatography/ tandem mass spectrometry (UHPLC-MS/MS) and heavy metals in blood samples were analysed by Agilent 7500C inductively coupled plasma-mass spectrometry. Renal function was assessed by using a simplified Modification of Diet in Renal Disease Study equation to estimate GFR. RESULTS: Blood lead was higher in herbal dispensing procedures (p=0.053) and in subjects who self-prescribe herbal medicine (p=0.057); mercury was also higher in subjects living in the workplace (p=0.03). Lower estimated GFR was significantly associated with lead (ß=-10.66, 95% CI -18.7 to -2.6) and mercury (ß=-12.52, 95% CI -24.3 to -0.8) with a significant interaction (p=0.01) between mercury and lead; however, estimated GFR was not significantly associated with high ALA-I level groups, arsenic and cadmium after adjusting for other confounding factors. CONCLUSIONS: We found that lower estimated GFR was associated with blood lead and mercury in herbalists after the ban of herbs containing ALAs in Taiwan. The ALA-I exposure did not show a significant negative association of estimated GFR, which might due to herbalists having known how to distinguish ALA herbs after the banning policy. Rigorous monitoring is still needed to protect herbalists and the general population who take herbs.

The role of essential metals in the placental transfer of lead from mother to child.

Epidemiological studies have found adverse birth and child health outcomes from prenatal lead exposure, but little is known about factors influencing placental transfer. In this study we describe the placental transfer of lead in a Taiwanese population, and investigate whether three essential metals - zinc, manganese, or selenium - influence transfer. Maternal and cord blood samples (308 pairs) from a birth cohort study were analyzed using multiple linear regression. There was a clear correlation between mother and child lead concentration (r=0.48, p<0.001), although lead concentration in cord blood (mean=1.29, SD=0.72 microg/dL) was lower than that for mothers (mean=1.58, SD=1.11 microg/dL). Cord blood lead was lower where the mother had a higher blood concentration of zinc (p<0.001) or manganese (p=0.02). Thus maternal blood zinc and manganese, but not selenium, appeared to decrease the placental transfer of lead. These findings raise the possibility of reducing placental transfer of lead by increasing zinc levels via nutritional supplementation during pregnancy.

Suspended onion particles and potential corneal injury in onion harvesters.

The authors suspected that suspended onion particles contributed to corneal ulcers in onion harvesters in southern Taiwan. In the present study, the authors used manikins to study suspended onion particles in fields in an effort to simulate typical conditions experienced by onion harvesters. An animal eye-exposure simulation study was also performed by the authors, who impacted suspended soil grains or onion particles onto the corneas of guinea pigs via aerosol generated from the Palas dispersion nozzle. The average size of 25.9 pm for suspended particles collected during the digging of onions was the largest one of those for various harvesting activities. Some onion skin flakes were found in samples obtained from gathering and packing activities; the typical flake size was approximately 3.5 x 2.5 mm2. The results of the animal study indicated that the size of soil grains has a demonstrable effect on the severity of corneal injury (p = .009). With respect to onion skin flakes, wind velocity was also associated significantly with the occurrence of corneal injury (p = .0004). A wind velocity threshold of 7 m/sec is recommended for the maintenance of safety, and if the wind speed exceeds this threshold level, workers should not engage in harvesting activities. Furthermore, use of appropriately designed goggles is necessary for the protection of onion harvesters who work in high-wind conditions.

Fungi genus and concentration in the air of onion fields and their opportunistic action related to mycotic keratitis.

The authors determined fungi concentrations and genera from onion fields located in monsoon and nonmonsoon areas of Taiwan, as well as concentrations from a county housing location, which served as the comparison site. The authors explored the relationship(s) among onion harvesting, monsoon characteristics, airborne fungal levels, and mycotic eye infection. Airborne fungal levels in the onion field in the nonmonsoon area were the highest, followed by decreasing levels in the monsoon area and control sites, regardless of the sampling periods. The geometric mean of airborne fungal concentrations was the highest during onion harvesting. Cladosporium was the most dominant fungus during pre- and postharvest seasons, whereas Aspergillus, Fusraium, Acremonium, Alternaria, Penicillium, Monilia, Mycelia, and Rhizopus were increased significantly during harvesting. Although fungal concentrations in monsoon onion fields were lower than concentrations measured in the nonmonsoon area, the invasion of dangerous fungal pathogens following eye trauma by airborne sharp exotics (e.g., onion flakes) dispersed in high wind may account for the increase in corneal ulcer cases that occur in the monsoon area.