Registration Dossier

Toxicological information

Repeated dose toxicity: oral

Currently viewing:

Administrative data

Endpoint:
chronic toxicity: oral
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
20-30 days; 6-12 months
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
Well-documented and corresponded to the criteria set for assessing animal studies in (Klimisch, et. al. 1996)- A Systematic Approach for Evaluating the Quality of Experimental Toxicological and Ecotoxicological Data, giving due consideration to the published data quality criteria in place at the time the study was conducted.

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
1979

Materials and methods

Principles of method if other than guideline:
The research techniques used in these investigations were developed by Krasovskii et al.(1976): Krasovskii, G.N., Varshavskaya, S.P., and Borisova, A.I. Toxic and gonadotropic effects of cadmium and boron relative to standards for the substance in drinking water. Environ. Health Perspect. 13:69 (1976) using Caremont and leblond "Spermogenesis of man, monkey, ram, and other mammals as shown by the periodic acid-Sciff acid techniques." Amer J. Anat. 96:229 (1955).
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent

Test animals

Species:
rat
Strain:
other: white rats
Sex:
not specified
Details on test animals and environmental conditions:
Details are reported in Krasovskii, G.N., Varshavskaya, S.P., and Borisova, A.I. Toxic and gonadotropic effects of cadmium and boron relative to standards for the substance in drinking water. Environ. Health Perspect. 13:69 (1976) which was unavailble at the time of input from the Journal of Environmental Perspectives.

Administration / exposure

Route of administration:
oral: unspecified
Vehicle:
not specified
Details on oral exposure:
The metals were administered orally each day to laboratory animals. lead acetate was administered in doses of 0.05, 0.005. and 0.0015mg/kg (based on ions of lead) to white rats; aluminum chloride in doses of 50, 17, and 6mg/kg (based on ions of aluminum) to rats and guinea pigs, 27, 9, and 3mg/kg to rabbits in short-term exposures, and 2.5, 0.25, and 0.0025mg/kg to rats in chronic exposures. These experiments were 0f 20-30 days and 6-12 months' duration.
Analytical verification of doses or concentrations:
not specified
Duration of treatment / exposure:
These experiments were of 20-30 days and 6-12 months' duration.
Frequency of treatment:
The metals (lead acetate and aluminum chloride) were administered orally each day to laboratory animals.
Doses / concentrationsopen allclose all
Dose / conc.:
0.05 other: mg/kg based on the ions of lead
Dose / conc.:
0.005 other: mg/kg based on the ions of lead
Dose / conc.:
0.002 other: mg/kg based on the ions of lead
Control animals:
yes
Details on study design:
Lead acetate was administered in doses of 0.05, 0.005, and 0.0015 mg/kg (based on the ions of lead) to white rats; aluminum chloride in doese of 50, 17, and 6 mg/kg (based on ions of aluminum) to rats and guinea pigs, 27, 9, and 3 mg/kg to rabbits in short-term exposures, and 2.5, 0.25, and 0.0025 mg/kg to rats in chronic exposures. These experiments were of 20-30 days and 6-12 months duration.
Positive control:
Yes

Examinations

Observations and examinations performed and frequency:
In the 6-12 month exposures with lead acetate, special attention was paid to the study of the excretion of alpha-aminolevulinic acid and coporphobilinogen in urine. In order to evaluate the effect of lead on the behavioral responses of animals, their motor activity was recorded by a method which tested conditioned reflexes. Also investigated were the functional and morphological conditions of spermatozoa and gonads. The blood chemistry of the animals and histological examination of rat livers and organ weights were observed in the short-term studies.

Results and discussion

Results of examinations

Clinical signs:
not specified
Mortality:
not specified
Body weight and weight changes:
effects observed, treatment-related
Food efficiency:
not specified
Ophthalmological findings:
not specified
Haematological findings:
effects observed, treatment-related
Clinical biochemistry findings:
effects observed, treatment-related
Urinalysis findings:
not specified
Behaviour (functional findings):
not specified
Immunological findings:
not specified
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Gross pathological findings:
not specified
Neuropathological findings:
not specified
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Histopathological findings: neoplastic:
not specified
Other effects:
not specified
Details on results:
The toxic effects of lead were observed when administered to rats in doses of 0.05 mg/kg. The activity of aldolase increased and the level of sulfhydryl groups decreased 5-10 days after intoxication (0< 0.01). The effect of the 0.005 mg/kg dose was expressed as a trend in the increase of aldolase in the blood serum. By the 20th day of intoxication the activity of aldolase normalized, and the activity of B-galactosidase, B-glucosidase, and acid phos- of B-galactosidaee, B-glucosidase, and acid phosphatase and cholesterol content of the blood serum did not change. In addition, substantial increases in the weight coefficients of liver and kidneys were observed with the 0.05 mg/kg doses of lead. A histological examination of the rat livers indicated a definite decrease in RNA and glycogen and in the activity of SDH, LDH, and NAD-diaphorase at all doses, and pyknosis of Kupffer cells at doses of 0.05mg/kg. Furthermore, small droplets of lipid inclusions were observed in the cytoplasm of epithelial cells located in the convoluted tubules of the cortical substance liver. The gonado toxic effect of lead was observed in animals which received the maximum dose. The functional conditional condition of spermatozoa changed and the acid phosphatase activity in the gonadal tissue increased being 25 +/- 1.0 for controls, 34.4 +/- 2.3 at 0.05 mg/kg, and 27.8 +/- 1.4 at 0.005 mg/kg; p < 0.05. The weight coefficients of gonads were increased only in animals which were exposed to the dose of 0.005 mg/kg. Small disruptions in the permability of the vessels and dystrophic changes in the Leydig cells were observed in the gonads, and the activity of oxidizing enzymes increased. In animals which were exposed to 0.0015 mg/kg of lead, no deviations in functional state was observed compared to the control group of animals.
Long-Term Exposure- In the 6-12 month exposures, special attention was paid to the study of the excretion of Alpha-aminolevulinic acid and coprophobilinogen in urine. The investigations showed that, beginning with the second month of intoxication, the excretion of alpha-aminoevulinic acid and of perphobilinogen gradually increased in animals which received lead in doses of 0.05 and 0.005 mg/kg. In order to evaluate the effect of lead on the behavioral responses of animals, their motor activity was recorded by a method which tested conditioned reflexes. Animals exposed to lead at 0.05 mg/kg and 0.005 mg/kg had disruptions in their conditioned responses (Table 2), and the wavelike motor activity underwent a shift of phase, depending on the season of the year. The investigation of functional and morphological conditions of spermatozoa and gonads indicated the gonadotoxic effect of lead in doses of 0.05 mg/kg (Table 3). The histological study of gonads indicated a swelling of the follicular epithelial cells; the vascular network was full of blood. The RNA content and sulfhydryl group content of some tubules increased, but decreased in the remaining part of the parenchyma. the activity of AIDH, SGH, NAD, and NADPH-diaphorase was substantially depressed in the spermatogenic epithelium and less depressed in the interstices. The indices of acitivity of acid phosphatase and of beta- glycosidase in gonadal tissues exposed to lead in doses of 0.05 mg/kg, 0.005 mg/kg, and 0.0015 mg/kg were, respectively, 58.5 +/- 3.0, 49.3 +/- 1.5, and 36.2 +/- 2.0 (controls 37.4 +/- 1.5) and 38.9 +/- 1.9, 64.0 +/- 5.4., annd 9.04 +/- 4.8 (controls (13.0 +/- 4.5). The histochemical study of the liver at doses of lead of 0.05 mg/kg and 0.005 mg/kg revealed a decrease in glycogen content, RNA, sulfhydryl groups and activity of oxidising enzymes in the central regions of obules and an increase of NAD and NADPH-diaphorase at the periphery of the lobules. In the kidneys the highest tested dose of 0.05 mg/kg only insignificantly increased chromosome abberrations. The 0.0015 mg/kg dose of lead (which corresponds to 0.03 mg lead/l. water) did not cause any changes. It can be considered that this does not have an effect on the organism

Effect levels

open allclose all
Dose descriptor:
LOEL
Effect level:
ca. 0.005 mg/kg bw/day (actual dose received)
Based on:
other: based on the ions of lead
Sex:
not specified
Basis for effect level:
haematology
Dose descriptor:
NOEL
Effect level:
ca. 0.002 mg/kg bw/day (actual dose received)
Based on:
other: based on the ions of lead
Sex:
not specified
Basis for effect level:
other: The 0.0015 mg/kg dose of lead (which corresponds to 0.03 mg lead/l water) did not cause any changes. It can be considered that this does not have an effect on the organism

Target system / organ toxicity

Critical effects observed:
not specified

Any other information on results incl. tables

Table 1 - Effect of Lead on Functional State of Spermatozoa

Test   Control   0.5 mg/kg   0.005 mg/kg   0.0015 mg/kg  
Motility of spermatozoa expressed in grades

 3.83 +/-0.17

 3.17 +/- 0.17*  3.5 +/- 0.22  3.83 +/- 0.17
 Acid stability of spermatozoa (pH) 3.04 +/- 0.097  3.3 +/- 0.028**  3.18 +/- 0.037  2.83 +/-0.048
 Osmotic stability of spermatozoa % NaCl  2.3 +/- 0.045  1.93 +/- 0.042***  1.97 +/- 0.033  38.5 +/- 0.34
 Time of motility of spermatozoa, hr  38.0 +/- 0.52  33.5 +/- 0.56***  37.33 +/- 0.33  38.5 +/- 0.34

*Significant at p<0.02

**Significant at P<0.05

***Significant at p<0.01

Effect of lead on conditioned reflex activity in case of chronic exposure

Test   Control   0.05 mg/kg   0.005mg/kg   0.0015mg/kg  
Manifestation of reflex (number of combinations  6.33 +/- 0.94  17.66 +/- 0.75*  10.16 +/-1.19**   6.83 +/-1.16
Consolidation of reflex (number of combinations)  3.66 +/- 2.21  35.16 +/- 1.53*  31.83 +/- 1.86**   24.16 +/- 2.89
Latent period  1.67 +/- 0.23  2.66 +/- 0.04**   2.03 +/- 0.15  1.69 +/-0.19
Conditioned Reflex  36.99 +/-6.31  2.66 +/- 0.04**   21.65 +/- 4.53  39.16 +/- 5.51
Unconditioned reflex  24.47 +/- 6.17  5.52 =/-3.25**   46.34 +/- 4.17***  25.47 +/- 5.26
Intersignal time  38.65 +/- 3.28  73.36 +/- 6.9**   44.5 +/- 6.20  35.41 +/- 5.0
Decrease of conditioned reflex  23.66 +/- 2.66  41.5 +/- 1.83*   20.5 +/-1.54  26.16 +/- 2.8
Restoration of conditioned reflex 3.83 +/- 0.86  10.66 +/- 0.55*   7.0 +/- 0.72***  3.33 +/- 0.41
*Significant at p < 0.01

**Significant at p <0.05

***Significant AT P<0.02

Table 2 - State of structural-functional elements of gonads in case of chronic lead intoxication

Tests   Tests   0.05 mg/kg   0.005 mg/kg   0.005 mg/kg   0.0015 mg/kg 
Spermatogenesis index  3.75 +/- 0.008  3.61 +/- 0.052*  3.72 +/- 0.0013   3.74 +/- 0.015  
  Number of tubules with cast-off epithelium  3.88 +/- 0.9  5.5 +/- 2.9   5.88 +/- 1.8  4.0 +/- 1.48
  Average number of spermatogonia  25.51 +/- 0.81  21.64 0.6**   20.84 +/- 1.35**  25.0 +/- 0.9
  Number of tubules with 12th meiosis stage  2.16 +/- 0.26  2.5 +/- 0.5   2.33 +/- 0.2  2.33 +/- 0.2
*Significant at p< 0.05

**Significant at p<0.01

Table 3- Indices of embryotoxic effect of lead

 

Test   Control   0.005 mg/kg     0.0015 mg/kg
Number of yellow bodies  11.76 +/- 0.04  11.0 +/- 0.67   10.9 +/- 1.07  
Number of live embryos  9.76 +/- 0.6   8.75 +/- 0.54  9.7 +/- 1.0
Number of resorptions  0.58 +/- 0.19   0.69 +/- 0.4  0.62 +/- 0.34
General mortality of embryos  16.8 +/- 1.76   20.6 +/- 0.4*  14.18 +/- 5.7
Preimplantation mortality  0.15 +/- 0.04   0.13 +/- 0.09  0.04 +/- 0.02
Postimplantation mortality  0.04 +/- 0.017  0.08 +/- 0.03  0.06 +/- 0.039
Average weight of embryo, g  2.35 +/- 0.21  2.18 +/- 0.15  2.29 +/- 0.06
Amount of lead in placenta, mg/g  5.33 +/- 0.85   9.47 +/- 2.4  5.4 +/- 1.42
Amount of lead in embryo, mg/g  2.74 +/- 0.62   5.6 +/- 1.1*  2.7 +/- 0.6

* Significant at p < 0.05

Applicant's summary and conclusion

Conclusions:
A concentration in water of 0.03 mg/l of lead can be considered safe for the health of the general public, and these could be recommended for inclusion into the public health standards for drinking water.
Executive summary:

A wide spectrum of biological effects of lead and aluminum ions is noted during short-term and long-term oral administration to laboratory animals. The general toxic and gonadotoxic effects of these metals during a short-term experiment appeared to be identical, and the correlation of these effects was preserved during chronic experiments. lead (0.03 mg/l) and aluminum (0.5 mg/l) concentrations in water may be dangerous to the health of the population, and hygienic standards are recommended for inclusion in the standard for drinking water quality.