Urinary porphyrins as biomarkers for arsenic exposure among susceptible populations in Guizhou province, China

Coal is widely used in PR China. Unfortunately, coal from some areas in Guizhou Province contains elevated levels of arsenic. This has caused arsenicosis in individuals who use arsenic-contaminated coal for the purposes of heating, cooking and drying of food in poorly ventilated dwellings. The population at risk has been estimated to be approximately 200,000 people. Clinical symptoms of arsenicosis may include changes of skin pigmentation, hyperkeratosis of hand and feet, skin cancers, liver damage, persistent cough and chronic bronchitis. We analyzed the porphyrin excretion profile using a HPLC method in urine samples collected from 113 villagers who lived in Xing Ren district, a coal-borne arsenicosis endemic area and from 30 villagers from Xing Yi where arsenicosis is not prevalent. Urinary porphyrins were higher in the arsenic exposed group than those in the control group. The correlation between urinary arsenic and porphyrin concentrations demonstrated the effect of arsenic on heme biosynthesis resulting in increased porphyrin excretion. Both uroporphyrin and coproporphyrin III showed significant increases in the excretion profile of the younger age (<20 years) arsenic-exposed group, suggesting that porphyrins could be used as early warning biomarkers of chronic arsenic exposure in humans. Greater increases of urinary arsenic and porphyrins in women, children and older age groups who spend much of their time indoors suggest that they might be at a higher risk. Whether elevated porphyrins could predict adverse health effects associated with both cancer and non-cancer end-points in chronically arsenic-exposed populations need further investigation.     

Chronic Arsenicosis of Cattle in West Bengal and It's Possible Mitigation by Sodium Thiosulfate

Thirty milch cows having arsenic concentration in hair varying from 3 to 4 mg/kg from Dakhin Panchpota village of Nadia district, West Bengal, were divided into three equal groups where high amount of arsenic is reported to be present in soil and ground water. Groups II and III received, respectively, sodium thiosulfate 20 and 40 g to each animal for 30 days as a pilot study, whereas group I served as untreated control. Arsenic content of milk, feces, hair, and urine was estimated before and after administration of sodium thiosulfate orally at two dose level once daily for 1 month. Paddy straw, mustard oil cake, and water fed by animals were also assayed. Sodium thiosulfate significantly decreased arsenic load in milk, urine, and hair after 1 month. In milk, arsenic concentration was decreased significantly which may be beneficial for animal and human beings.     

Changes in egg composition of American kestrels exposed to dietary polychlorinated biphenyls

Changes in the quality of eggs of birds exposed to polychlorinated biphenyls (PCBs) have been described, but have never been directly attributed to PCBs. Polychlorinated biphenyl residues in eggs have been associated with reduced reproductive success and embryonic deformities in wild birds. Egg size and composition, specifically the amount of albumen, yolk, and water in an egg, also influence the growth and viability of embryos and hatchlings, and consequently the reproductive success of birds. To deter mine whether PCB exposure of adult birds affected the size and composition of their eggs, 25 pairs of captive American kestrels (Falco sparverius) were fed a mixture of PCB-spiked (1248:1254:1260) food to give an approximate exposure of 7 mg/kg body weight/d, beginning 1 mo prior to pairing, and continuing throughout the courtship, egg-laying, and incubation periods. This dietary level in the adult female kestrels resulted in mean total PCB residues in the eggs of 34.1 microg/g wet weight (geometric mean), which is environmentally relevant. PCB residues in eggs increased with the time of female exposure to the contaminated diet and laying date. Variation in egg size within PCB clutches was significantly greater than within control clutches, although absolute egg mass and volume did not differ markedly by treatment. Only infertile eggs and only one egg per clutch were used for egg composition analysis. Yolks in the PCB-contaminated eggs were heavier, with less wet and dry albumen relative to control eggs. Water content and eggshell thickness were not significantly affected by PCB exposure. These results suggest that eggs from the PCB treatment have relatively more lipid and less protein available for embryonic development. Changes in egg composition were not associated with egg size, lay date, ambient temperature, humidity, or precipitation, which are factors known to affect these variables in bird eggs. The PCB-induced changes in egg composition described here provide insight into possible mechanisms contributing to reduced reproductive performance in wild birds exposed to PCBs.     

贵州省实施燃煤污染型砷中毒综合防制项目效果评估

目的评价采取综合措施控制贵州省燃煤型地方性砷中毒(地砷病)病区砷污染的效果。方法实施以健康教育为基础,禁止开采高砷煤和改良炉灶为主的综合防治措施后,采取随机抽样的方法对其效果进行评估。结果通过强有力的健康促进,在病区,砷中毒防治知识家喻户晓,深入人心;高砷煤开采得到基本禁止;全部家庭用上了有排烟设施的炉灶,炉灶正确使用率达到90%;家庭玉米和辣椒正确干燥率均达到90%以上;大多数家庭已经养成烹调前淘洗食物的习惯,有效的将煤烟排出室外,基本避免了玉米和辣椒等食物污染,减少了砷的摄入量,机体尿砷排泄显著减少,接近正常人排泄水平。结论在地砷病区实施综合控制措施取得预期成效。     

Aflatoxin deposition and clearance in the eggs of laying hens

Hens fed a diet containing 3310 μg of AFB₁ and 1680 μg of AFB₂ per kg feed for 28 days showed a significant decrease in egg production and egg weights by wk 3 and 4 of feeding, respectively. Transfer of aflatoxins to the eggs occurred rapidly, reaching maximum levels after 4–5 days, and remained relatively constant throughout aflatoxin feeding. The mean values for combined residue levels in eggs were less than 0.5 μg/kg. Levels of AFB₂, AFM₁ and AFM₂ were similar in yolk and albumen while levels of B₁ and B_2a were higher in the yolk. Upon removal of the aflatoxin-containing diet, residues in eggs decreased rapidly. Clearance of aflatoxin residues from the albumen occurred faster than from the yolk. Thus, no residues were detected in the albumen and in the yolk after 5 and 7 days of withdrawal, respectively. No aflatoxin residues could be recovered from whole eggs after feeding the aflatoxin-free diet for 4 days.     

CHANGES IN EGG COMPOSITION OF AMERICAN KESTRELS EXPOSED TO DIETARY POLYCHLORINATED BIPHENYLS

Changes in the quality of eggs of birds exposed to polychlorinated biphenyls (PCBs) have been described, but have never been directly attributed to PCBs. Polychlorinated biphenyl residues in eggs have been associated with reduced reproductive success and embryonic deformities in wild birds. Egg size and composition, specifically the amount of albumen, yolk, and water in an egg, also influence the growth and viability of embryos and hatchlings, and consequently the reproductive success of birds. To deter mine whether PCB exposure of adult birds affected the size and composition of their eggs, 25 pairs of captive American kestrels (Falco sparverius) were fed a mixture of PCB-spiked (1248:1254:1260) food to give an approximate exposure of 7 mg/kg body weight/d, beginning 1 mo prior to pairing, and continuing throughout the courtship, egg-laying, and incubation periods. This dietary level in the adult female kestrels resulted in mean total PCB residues in the eggs of 34.1 µg/g wet weight (geometric mean), which is environmentally relevant. PCB residues in eggs increased with the time of female exposure to the contaminated diet and laying date. Variation in egg size within PCB clutches was significantly greater than within control clutches, although absolute egg mass and volume did not differ markedly by treatment. Only infertile eggs and only one egg per clutch were used for egg composition analysis. Yolks in the PCB-contaminated eggs were heavier, with less wet and dry albumen relative to control eggs. Water content and eggshell thickness were not significantly affected by PCB exposure. These results suggest that eggs from the PCB treatment have relatively more lipid and less protein available for embryonic development. Changes in egg composition were not associated with egg size, lay date, ambient temperature, humidity, or precipitation, which are factors known to affect these variables in bird eggs. The PCB-induced changes in egg composition described here provide insight into possible mechanisms contributing to reduced reproductive performance in wild birds exposed to PCBs.     

Chronic arsenicosis in goats with special reference to its exposure, excretion and deposition in an arsenic contaminated zone

Thirty goats were selected randomly from a village of Nadia district, West Bengal according to the previous reports of human being suffering from chronic arsenicosis. Environmental samples viz. drinking water, rice plants and grass used for goat and biological samples viz. blood, urine, faeces, hair and meat were collected to evaluate the arsenic status. It was found that arsenic concentration in both environmental and biological samples was significantly (p<0.01) higher rather than respective samples on control zone. Bio-concentration factor (BCF) and bio-transfer factor (BTF) are indicated to evaluate the subclinical toxicity in goat as they do not exhibit clinical manifestation like human beings.     

Studies on the tissue disposition and fate of [14C]toxaphene in Japanese quail

The disposition and the fate of a [14C]toxaphene preparation was studied in adult and juvenile female Japanese quail. The distribution of [14C]toxaphene in the body is dominated by high concentrations of radioactivity in the adipose tissue and the egg yolk, and, especially in juvenile birds, in the bone marrow. The [14C]toxaphene compounds present in the fat tend to be less polar than the parent [14C]toxaphene. More than half of the radioactive dose is excreted via the droppings, eggs, and preen gland within a few days, with biliary excretion playing a major role. The main part of the radioactivity in feces and urine consists of water soluble compounds, a part of which is indicated to be glucuronide and sulfate conjugates, but other metabolites are probably also present. A possible connection between the toxaphene residues in the bone and the known toxaphene induced osteomalacia in birds is discussed.     

The Distribution of 14C–Chloramphenicol in the Japanese Quail (Coturnix coturnix japonica)

Abstract: The distribution of ¹⁴C–labelled chloramphenicol after oral and intravenous administration to egg laying Japanese quail was studied by whole–body autoradiography. In the liver, kidneys, gizzard, intestinal contents (bile) and oviduct, the ¹⁴C–concentration was higher than that of the blood short time after injection and remained higher than the blood up to 4 days. From 4 hrs, the concentration of ¹⁴C in the egg yolks was higher than that of the blood and from 24 hrs the radioactivity in the albumen of the eggs in the oviduct was also higher than that of the blood. The peak concentration in the egg yolk was found in the second egg laid 2–4 days after administration of ¹⁴C–chloramphenicol. In the albumen the maximum concentration was found in the first laid egg 24–48 hrs after administration. In the egg yolks, about 30% of the radioactivity represented unchanged chloramphenicol up to 5 days after administration. It was also shown that about 5% of the injected ¹⁴C–chloramphenicol was exhaled as ¹⁴CO₂ during the first 12 hrs and about 37% of the dose was excreted in the combined faeces and urine during the same period of time     

Arsenic contamination and arsenicosis in China

Arsenicosis is a serious environmental chemical disease in China mainly caused by drinking water from pump wells contaminated by high levels of arsenic. Chronic exposure of humans to high concentrations of arsenic in drinking water is associated with skin lesions, peripheral vascular disease, hypertension, blackfoot disease, and high risk of cancers. Lead by the Ministry of Health of China, we carried out a research about arsenicosis in China recently. Areas contaminated with arsenic from drinking water are determined by 10% pump well water sample method while areas from burning coal are determined by existing data. Two epidemic areas of Shanxi Province and Inner Mongolia are investigated for the distribution of pump wells containing high arsenic. Well water in all the investigated villages of Shanxi Province showed polluted by high arsenic, and the average rate of unsafe pump well water is 52%. In Inner Mongolia, the high percentage of pump wells containing elevated arsenic is found only in a few villages. The average rate of unsafe pump well water is 11%. From our research, we find that new endemic areas are continuously emerging in China. Up to now, epidemic areas of arsenicosis mainly involve eight provinces and 37 counties in China. In the affected areas, the discovery of wells and coal with high levels of arsenic is continuing sporadically, and a similar scattered distribution pattern of patients is also being observed.     

The distribution of 14C-chloramphenicol in the Japanese quail (Coturnix coturnix japonica)

The distribution of 14C-labelled chloramphenicol after oral and intravenous administration to egg laying Japanese quail was studied by whole-body autoradiography. In the liver, kidneys, gizzard, intestinal contents (bile) and oviduct, the 14C-concentration was higher than that of the blood short time after injection and remained higher than the blood up to 4 days. From 4 hrs, the concentration of 14C in the egg yolks was higher than that of the blood and from 24 hrs the radioactivity in the albumen of the eggs in the oviduct was also higher than that of the blood. The peak concentration in the egg yolk was found in the second egg laid 2-4 days after administration of 14C-chloramphenicol. In the albumen the maximum concentration was found in the first laid egg 24-48 hrs after administration. In the egg yolks, about 30% of the radioactivity represented unchanged chloramphenicol up to 5 days after administration. It was also shown that about 5% of the injected 14C-chloramphenicol was exhaled as 14CO2 during the first 12 hrs and about 37% of the dose was excreted in the combined faeces and urine during the same period of time.     

Toxicity and distribution of 2-methyl-4-chlorophenoxyacetic acid (MCPA) in developing chick embryos

The toxicity of the herbicide Erbitox E30, a commercial formulation of 2-methyl-4-chlorophenoxyacetic acid (MCPA) containing 28% MCPA as sodium-potassium salt and 72% of unknown ingredients, was tested on chick embryos. Sterile aqueous solutions of MCPA were injected into the air chamber at doses of 0, 1.5, 3.0, 6.0, 9.0, or 10.5 mg/egg on day 0 or on day 4 of incubation. The mortality rate for the embryos treated on day 0 of incubation was high in the first 5 days, low from 5-12 days and again increased by 15 days. The 15-day LD50 was 4.4 mg/egg (95% C.I. 3.7-5.3 mg/egg). HPLC analysis of albumen and yolk showed that concentrations of MCPA in the albumen were detectable at 5 min, highest at 7 days and markedly diminished by 14 days of incubation; a significantly lower concentration of MCPA was found in the yolk throughout the incubation period, except at 14 days when the yolk concentration was 4 times higher than the albumen concentration. At 15 days of incubation, MCPA was evenly distributed in the tissues of the embryo. MCPA was more toxic to 4-day embryos; concentrations above 6.0 mg/egg were lethal to all embryos within the first week of incubation. The 15-day LD50 for treatment on day 4 of incubation was 2.8 mg/egg (95% C.I. 2.5-3.2 mg/egg). The liver was affected by treatment with MCPA, being green in treated embryos. However, histological examination revealed few changes in the liver parenchyma.     

Metabolism and excretion of orally administrated arsenic trioxide in the hamster

It was shown that a single dose of arsenic trioxide administered to hamsters was chiefly methylated in vivo into methylarsonic acid (MAA) and dimethylarsinic acid (DMAA), and that inorganic arsenic accounted for the major portion of total arsenic that deposited in organs and tissues, followed by MAA and DMAA in decreasing sequence of significance. The single oral dose of arsenic trioxide was followed by a very small amount of trimethylarsenic compounds (TMA) occurring only in the liver but not in any other organs, tissues, blood or feces. The distribution pattern of arsenic in the blood following the single oral dose of arsenic trioxide was such that inorganic arsenic and MAA occurred chiefly in the blood cells; DMAA, chiefly in the plasma; and the arsenic compounds disappeared rapidly from blood. The single oral dose of arsenic trioxide was further followed by excretion of an amount of arsenic equivalent to about 60% of the administered dose: 49% in the urine and 11% in the feces. In other words, more arsenic tended to be excreted in the urine. DMAA accounted for the major portion of arsenic excreted in the urine and feces, and this finding re-confirmed that DMAA is the major metabolite of arsenic trioxide. Although it is believed that arsenic trioxide is not converted into TMA, the results of the present study suggest that a very small amount of arsenic trioxide is converted into TMA in the liver.     

Chronic arsenic toxicity in Bangladesh and West Bengal, India--a review and commentary.

Fifty districts of Bangladesh and 9 districts in West Bengal, India have arsenic levels in groundwater above the World Health Organization's maximum permissible limit of 50 microg/L. The area and population of 50 districts of Bangladesh and 9 districts in West Bengal are 118,849 km2 and 104.9 million and 38,865 km2 and 42.7 million, respectively. Our current data show arsenic levels above 50 microg/ L in 2000 villages, 178 police stations of 50 affected districts in Bangladesh and 2600 villages, 74 police stations/blocks of 9 affected districts in West Bengal. We have so far analyzed 34,000 and 101,934 hand tube-well water samples from Bangladesh and West Bengal respectively by FI-HG-AAS of which 56% and 52%, respectively, contained arsenic above 10 microg/L and 37% and 25% arsenic above 50 microg/L. In our preliminary study 18,000 persons in Bangladesh and 86,000 persons in West Bengal were clinically examined in arsenic-affected districts. Of them, 3695 (20.6% including 6.11% children) in Bangladesh and 8500 (9.8% including 1.7% children) in West Bengal had arsenical dermatological features. Symptoms of chronic arsenic toxicity developed insidiously after 6 months to 2 years or more of exposure. The time of onset depends on the concentration of arsenic in the drinking water, volume of intake, and the health and nutritional status of individuals. Major dermatological signs are diffuse or spotted melanosis, leucomelanosis, and keratosis. Chronic arsenicosis is a multisystem disorder. Apart from generalized weakness, appetite and weight loss, and anemia, our patients had symptoms relating to involvement of the lungs, gastrointestinal system, liver, spleen, genitourinary system, hemopoietic system, eyes, nervous system, and cardiovascular system. We found evidence of arsenic neuropathy in 37.3% (154 of 413 cases) in one group and 86.8% (33 of 38 cases) in another. Most of these cases had mild and predominantly sensory neuropathy. Central nervous system involvement was evident with and without neuropathy. Electrodiagnostic studies proved helpful for the diagnosis of neurological involvement. Advanced neglected cases with many years of exposure presented with cancer of skin and of the lung, liver, kidney, and bladder. The diagnosis of subclinical arsenicosis was made in 83%, 93%, and 95% of hair, nail and urine samples, respectively, in Bangladesh; and 57%, 83%, and 89% of hair, nail, and urine samples, respectively in West Bengal. Approximately 90% of children below 11 years of age living in the affected areas show hair and nail arsenic above the normal level. Children appear to have a higher body burden than adults despite fewer dermatological manifestations. Limited trials of 4 arsenic chelators in the treatment of chronic arsenic toxicity in West Bengal over the last 2 decades do not provide any clinical, biochemical, or histopathological benefit except for the accompanying preliminary report of clinical benefit with dimercaptopropanesulfonate therapy. Extensive efforts are needed in both countries to combat the arsenic crisis including control of tube-wells, watershed management with effective use of the prodigious supplies of surface water, traditional water management, public awareness programs, and education concerning the apparent benefits of optimal nutrition.     

Arsenic speciation in the urine and hair of individuals exposed to airborne arsenic through coal-burning in Guizhou,PR China

The extent of exposure of residents of Changqing (Guizhou, PR China) to arsenic through coal-burning was investigated. Despite the low coal-arsenic content (56.3+/-42.5 mg As kg(-1)) when compared with coals collected at different location and times from the same province, more than 30% of the study subjects have shown symptoms of arsenicosis. Coal, urine, hair, and water samples were collected in mid-September 2001 and analysed for arsenic. The average urinary and hair-arsenic concentrations in the exposed subjects were 71.4+/-37.1 microg As g(-1) creatinine (control 41.6+/-12.1) and 7.99+/-8.16 mg kg(-1), respectively. A positive correlation between the hair and urinary-arsenic concentration (R(2)=0.601) was found. There was no significant difference between females and males for both urinary and hair-arsenic concentrations. Females were found to have a higher dimethylarsinic acid but lower percentages of inorganic arsenic and monomethylarsonic acid in their urine than males.     

Development and validation of a herring gull embryo toxicokinetic model for PCBs

A toxicokinetic model was developed to describe polychlorinated biphenyl (PCB) accumulation by herring gull (Larus argentatus) embryos during development. The model consists of two components, a bioenergetics model that predicts the lipid mass balance of embryo and yolk compartments with time and an empirical toxicokinetic model that describes PCB partitioning between lipid compartments in the egg. The model was calibrated using data on PCB and lipid partitioning between embryo and yolk+albumen at four time points during incubation in herring gull eggs injected with a PCB mixture, combined with data sets on herring gull embryo growth rates and bioenergetic demands with time. The model was validated using independent data consisting of maternally exposed, field-incubated Lake Superior herring gull eggs that varied in incubation ages over the range of 8.5 d to pipping age (26–28 days). PCB concentrations in 6–9 d embryos were nearly an order of magnitude less than predicted by equilibrium lipid partitioning between the embryo and yolk+albumen compartments of the eggs. PCB concentrations in embryos were adequately predicted by equilibrium partitioning, however, for eggs incubated for 23–28 d. An empirical relationship was developed to account for the apparent non-equilibrium behaviour of PCBs during early development. The model was sensitive to the mass of yolk lipids and the mass of PCBs deposited to fresh eggs and much of the variability in embryo PCB concentrations could by explained by accounting for variability in these input parameters. Consistent with experimental data for other avian species, the model predicts that the highest PCB concentrations in the embryo/chick occur during pipping or soon after when yolk lipids have been completely resorbed by the embryo.     

Uptake and distribution of 2,5,2',5'-tetrachlorobiphenyl in developing lake trout.

Lake trout (Salvelinus namaycush) eggs, sac fry, and fry in which the yolk had been absorbed were exposed to water containing a 500 μg/liter (ppb) calculated concentration of ¹⁴C-labeled 2,5,2′,5′-tetrachlorobiphenyl (TCB). By determining the amount of radioactivity in water and tissue samples at times ranging from 0.5 to 4 hr, the disappearance of the TCB from the water and its uptake by the animals were followed. The data show that the TCB passed through the egg chorion and accumulated in the yolk. Eggs thus exposed and followed through 4 weeks after hatching lost none of the labeled TCB. Sac fry and fry in which the yolk sac had been absorbed took up the TCB more quickly and accumulated higher concentrations than eggs, achieving concentrations of about 6 ppm in 4 hr. When eggs were exposed to water containing TCB, and the eggs or the sac fry that hatched from them were analyzed, 87–88% of the TCB was found in the yolk. When sac fry were exposed directly to water containing TCB, 70% of the label was found in fry tissues other than the yolk. Thus, the route of entry and the tissue concentration and distribution of TCB in lake trout may depend, in part, on the developmental stage at which the animals are exposed.     

Developmental stage dependent toxicity of aminoguanidine on chick embryos

Aminoguanidine (AG) sulfate was injected into the thin albumen of fertile eggs on the different days of incubation. The lethality of AG sulfate on the developing chick embryos became lower when the treatment was done at later developmental stage. When AG was injected on the 5th day of incubation, the frequency of retardation of development of the body and liver, aplasia of gallbladder and enlarged spleen was highest without high mortality compared with the other experiments. Embryos with liver damage could not hatch. 14C-AG hydrochloride injected on the 5th day of incubation easily distributed into the embryo through the yolk from the thin albumen of the injection site, but when injected on the 9th day, the agent transferred very little into the yolk and embryo. The change of transport in the eggs with development may elucidate the difference of lethality of AG. Additionally, it was confirmed using thin layer chromatography that a large part of the radioactivity in the embryo might be an unknown metabolite of AG and the substance was accumulated with extremely high concentration in the liver at 24-48 hr after the injection of AG on the 5th day of incubation. This is probably the main cause of the peculier abnormalities in the liver of chick embryos.     

Distribution of bisphenol A and tetrabromobisphenol A in quail eggs, embryos and laying birds and studies on reproduction variables in adults following in ovo exposure

In a previous study, we showed that bisphenol A (BPA) had oestrogen-like effects in bird embryos, causing malformations of the oviducts in Japanese quail (Coturnix japonica) and feminisation of the left testis in chicken (Gallus domesticus). In this study, uptake and distribution of BPA and tetrabromobisphenol A (TBBPA) in embryos and laying quail were examined as well as variables related to reproduction in adult quail following administration of the compounds into the yolk of embryonated eggs. The uptake of radiolabelled BPA, TBBPA and the reference compound diethylstilboestrol (DES) was studied in the embryos using beta-spectrometry. Autoradiography was employed to examine distribution in egg and embryo after yolk sac injection of BPA or TBBPA and in laying birds, following intravenous and oral administration. Following embryonic exposure to BPA or TBBPA, sexually mature male birds were examined for reproductive behaviour and testis morphology, and females were examined for egg laying and oviduct morphology. Neither BPA (200 microg/g egg) nor TBBPA (15 microg/g egg) caused any significant oestrogen-like effects on the variables studied, although effects on the female oviducts after BPA exposure were indicated. Embryonic exposure to DES is known to cause profound effects on male sexual behaviour and female oviduct morphology at doses 3-5 orders of magnitude lower than the BPA and TBBPA doses used in the present study. The proportions of BPA and TBBPA taken up by the embryos after yolk sac injection were similar to the proportion of DES taken up. Differences in bioavailability, therefore do not account for any major part of the potency differences between DES and the two bisphenol A compounds. The concentration of radioactivity in the embryo, as revealed by autoradiography, was low compared with that in the yolk at all stages studied (days 6, 10 and 15). Pronounced labelling of the bile and the allantoic fluid was observed, however, indicating that both compounds were readily metabolised and excreted. Radiolabelled BPA and TBBPA administered to laying quail were largely excreted via the bile and 9 days after oral dosing, only small amounts of the labelled compound remained within the body. Maternal transfer of labelled BPA and TBBPA to the egg was low.     

Biotransformation of dimethylarsinic acid in mouse, hamster and man

The metabolism of dimethylarsinic acid (DMA) a common pesticide and the main metabolite of inorganic arsenic in mammals, has been studied in mice, hamsters and man. Mice and hamsters were administered a single dose of 74As-DMA (40 mg As/kg body weight) orally, while a human subject ingested DMA corresponding to 0.1 mg As/kg body weight. Ion exchange chromatography, paper electrophoresis, thin layer chromatography as well as arsine generation--gas chromatography combined with atomic absorption spectrophotometry or mass spectrometry were used to characterize the arsenic metabolites in urine and feces collected over 48 hours after treatment. In mice and hamsters 3.5% and 6.4% of the dose, respectively, were excreted in urine in the form of trimethylarsine oxide (TMAO). No TMAO was found in feces. A DMA-complex was detected in urine and feces. It amounted to about 13% of the dose in mice and 15% in hamsters. About 80-85% of the dose was eliminated in urine and feces in the form of unmetabolized DMA. No demethylation of DMA to inorganic arsenic was observed. In man, about 4% of the dose was excreted in urine as TMAO and about 80% as DMA.