Study On The Health Effects Of Patina

Copper is widely used in drinking facilities,tubing and piping in the distribution system of drinking water throughout the world,and its application is largely increasing.Despite its advantage of anti-bacteria property,copper could be corroded and forms patina by oxidation reaction due to the presence of water and air,especially under environment with high humidity and high temperature.Natural patina is composed of multi-chemical compounds and might be toxic So the chances of human exposed copper and its corrosion products-patina are increased.Human and animal studies indicated that gastrointestinal(GI) tract is the target organ for toxicity effects of copper compounds.Current researches only involved one single copper compound and the toxicity of patina was not studied,so the healthy effects of patina occuring as a composite is an increasing field of academic research.In this study,the patina was prepared in natural process with high humidity,high temperature,high chloridion(Cl^-) and air.Considering the compositions of patina are related with health hazardous effects,in this paper X ray diffraction was used for qualitative and quantitive information of patina composition.The results showed that the patina in this experiment was relatively voluminous, friable tubercles of green-colored,and the main components of patina were basic cupric chloride(Cu₂(OH)₃Cl^- and Cu(OH)Cl^-),basic cupric sulfates (Cu₄(SO₄)(OH)₆(H₂P)) and basic curpic carbonate(Cu₂·(CO₃)(OH)₂).The second part of the paper was animal experiment on acute toxic effects in rats and mice.In each experiment,ninety healthy-adult animals were distributed to eight treatment groups and one control group randomly.The SD rats in eight experimental groups,given respectively the patina at the doses of 217.3,325.9,488.9,625.0,733.3, 1100.0,1250.0 and 1775.0mg/kg b.w..And the ICR mice in the treatment groups were given respectively the patina at the doses of 533,600,800,1200,1800,2700, 4050 and 5000mg/kg b.w..In both experiments,the animals in the negative control group were given patina at a dose of 0 mg/kg(0.5%sodium carboxy methyl cellulose (CMC)(1.5ml/10kg b.w.) by gavage.Within 24h,animals were administrated with patina suspended in 0.5%CMC three times by gavage according to 1.5ml/100g b.w.. Next,the movement,intoxication symptoms and mortalities were observed for 14 days.The number of survivors and body weights after the 14 days were recorded.The animals were then sacrificed for pathological examination of liver,stomach and kidney.The results showed that the LD₅₀ and its 95%CI of patina on ICR mouse were 1349.96mg/kg(1698.24～1071.52mg/kg).The SD rat was more sensitive than the ICR mouse as the LD₅₀ of patina was 732.3mg/kg and its 95%CI was 870.96～615.18 mg/kg.Pathology examination conducted on 15th day revealed the swelling, vacuole degeneration and necrosis of liver damage on rats and mice.In the third part,the subchronic healthy effects of patina and its solutions on rats were studies by gavage and drinking water respectively continuously for 90days.The doses of patina administrated by oral gavage were respectively 7.3,24.4,73.2mg/kg b.w,and animals in the control group were received 0.5%CMC by oral gavage.And the concentrations of patina solution by dringing water freely were 0,500,1000, 2000mg/L.The results showed that all animals survived and exhibited normal general behavior.Animals in the group of 7.3 mg/kg patina showed a significant increase of body weights compared to the control group;when compared with the controls, stomach index of males in 73.2mg/kg group and femals in 24.4mg/kg and 73.2mg/kg groups were significantly increased.The various biochemical parameters like ALT, AKP,CK and NAG in all experimental groups showed no statistical difference between patina treated groups and the control,but the LDH level in 73.2mg/kg group was significantly decreased,when compared with the control.In addition,except the heart SOD acivities in the 73.2mg/kg,the SOD activities of liver,heart and brain in the patina treatment groups were significant higher than that in control group;and in the 24.4 and 73.2mg/kg group,the SOD,GSH—Px activities of stomach were marked decrease and MDA levels of stomach were significant increased.Pathology examination showed no significant changes in the brain,liver,heart,kidney and spleen histopathology,besides slight damage to stomach in 73.2mg/kg group,which showed significant hyperplasia of stomach epithelium.Meanwhile,the animals treated by drinking patina solutions did not showed serious abnormal in general behavior, body weights,pathology,serum and urine biochemistry,the level of antioxidative enzyme and oxidative stress of organs.Based on these results,a 3-month administration of patina and patina solutions at varied doses doe not cause any severe toxic effects.In the 24.4 and 73.2 mg/kg patina treated groups,the copper concentrations in the liver were significantly increated compared with that of control group;and there is no significant difference of copper in serum,kidney and musule.In the groups treated by patina solutions,there is no significant difference in the copper concentration in the serum,liver,kidney and musule.The results suggested that the levels of copper liver could reflect the patina exposure levels of rats;serum copper and kidney copper were not sensitive exposure markers for patina under this exposure scenario.Micronucleus test was used to study the chromosome aberration of patina on mice. No statistically significant increase in the incidence of MN was observed in the bone marrow of mice treated with patina when compared with those of untreated control animals.The data in mice treated with different doses of patina did not show statistically significant difference.Conclusion from these results could reach that patina did not induce the effects of chromosome aberration on mice.