Research On Endocrine Disrupting Effects Of Exposure To E-waste Pollution In Local Residents From An E-waste Dismantling Region

The electronics industry is the world's largest and fastest growing manufacturing industry, and as a consequence of this growth, electrical and electronic waste (e-waste) such as computers, printers, mobile phones, television sets, stereos, radios, etc., is generated in large quantities around the world. Large quantities of chenmicals generated during e-waste disposal, for instance, polybrominated diphenyl ethers (PBDEs), heavy metals are released into the surrounding area, resulting in pollution and threaten the human health.PBDEs, a widely used as flame retardants in eletronic products, enters the environment readily via various pathways. Prople are exposed to it through inhalation, dermal exposure, and oral intake. Wang et.al reported the PBDEs pollutions in the e-waste dismantling site where we chosed that PBDEs content in the soil ranged in 0.26-824 ng/g, 10-60 times higher than other reported areas. Recent years, detected levels of PBDEs showed an increasing trend, in the biological samples including human serum, breast milk and adipose tissue, which are reported by many countries in the world. Evidence suggests that PBDEs exposure could disturb endocrine function, and impact on functions of liver, nervous system, reproduction, and growth in the organisms. However, the mechanisms of adverse effects of PBDEs on the organisms are unclear, and few studies related to adverse effetcts of PBDEs on human.Because there is limited evidence of the impacts of PBDEs on human health, the aims of the present study were to disclose the potential heath effects of e-waste to local residents. Data comes from the determination of the levels of thyroid hormones sexual hormones and corresponding mRNA expression in local residents from the e-waste recycling site in southeast China that has existed for more than a decade. PartⅠResearch on endocrine disrupting effects of exposure to e-waste pollution in the residents from an e-waste dismantling region【Objective】Sera levels of thyroid hormones and sexual hormones of residents from an e-waste dismantling region were investigated.【Methods】We detected the sera levels, including thyroid hormones free triiodothyronine (FT3), free thyroxine (FT4), thyroid stimulating hormone (TSH) and sexual hormones, including estradiol (E2) and progesterone (Pro), testerone (T) among the subjects from the control group (n=80) and the exposed group (n=58) by immuno-chemiluminometric assay. The factors relating to levels of these hormones were further analyzed. .【Results】Sera FT4 levels in the exposed group were significantly lower than those in the control (P<0.01). However, increased sera TSH levels in the exposed group were statistically significance compared with the control group (P<0.01). Sera levels of E2 and T among the male subjects residents in the exposed group were significant lower than those in the control (P<0.05). By contrary, sera Pro levels in female residents from the exposed group were significant higher, compared with the control group (P<0.05). In addition, we found that the factors including history of working with e-waste may be a risk factor that may affect serum TSH level (OR=3.88,P<0.01), Both gender(OR=0.39,P<0.05)and possession status of electronic goods(OR=0.33, P<0.05)may be protective factors to sera FT3 levels.【Conclusions】The findings suggest that some environmental pollutants existing in e-waste dismantling region may affect local residents'health, representing changes in sera levels of thyroid hormones and sexual hormones.PartⅡResearch on endocrine disrupting effects of exposure to e-waste pollution in the puerperants from an e-waste dismantling region【Objective】The levels of thyroid hormones, sexual hormones and their receptor expression in the parturient women from an e-waste dismantling region were investigated.【Methods】We detected the sera levels, including FT3, FT4, TSH and sexual hormones, including E2 , Pro, T among the subjects from the exposed group (n=48) and the control group(n=45)by immuno radiometric assay ( IRMA ). The mRNA expression levels of TRα1, TRβ1, TSHR, ERα, ERβ, PR in placentas were detected by fluorscent quantitative real time PCR (FQ-PCR).【Results】①The FT4 levels of maternal sera in the exposed group were lower than those in the control (P<0.05). However, increased the TSH levels in the exposed group were statistically significance compared to the control group (P<0.05).②Both E2 and Pro levels of maternal sera in the exposed group were higher than those in the control (P<0.05).③The TRα1 and TRβ1 mRNA levels in placentas in exposed group were lower than those in control group (P<0.05, P<0.01). However, the TSHR mRNA levels in the exposed group were statistically significance compared to the control group (P<0.01).④The ERαand ERβmRNA levels in placentas in exposed group were higher than those in control group (P<0.01). However, the PR mRNA levels in the exposed group were statistically significance compared to the control group (P<0.05).【Conclusions】The findings suggest that some environmental pollutants existing in e-waste dismantling region may affect the health of local parturient women and newborns, representing changes both in sera levels of thyroid hormones, sexal hormones and in mRNA expression of their receptors.PartⅢResearch on endocrine disrupting effects of exposure to e-waste pollution in the newborns from an e-waste dismantling region【Objective】The levels of thyroid hormones, sexual hormones and their receptor expression in the newborns from an e-waste dismantling region were investigated.【Methods】We detected the sera levels, including thyroid hormones FT3, FT4, TSH and sexual hormones, including estradiol (E2) and progesterone(Pro),testeron(T)among the subjects from the exposed group (n=48) and the control group(n=45)by immuno radiometric assay ( IRMA ). The expression levels of TRα1, TRβ1, TSHR, ERα, ERβ, PR mRNA in umbilical cords were detected by fluorscent quantitative real time PCR (FQ-PCR).【Results】①The FT4 levels of umbilical cord sera in the exposed group were lower than those in the control (P<0.05). However, increased the TSH levels in the exposed group were statistically significance compared to the control group (P<0.05).②Both E2 and Pro levels of umbilical cord sera in the exposed group were higher than those in the control (P<0.05).③The TRα1 and TRβ1 mRNA levels in umbilical cords in exposed group were lower than those in control group (P<0.05, P<0.01). However, the TSHR mRNA levels in the exposed group were statistically significance compared to the control group (P<0.01).④The ERαand ERβmRNA levels in umbilical cords in exposed group were higher than those in control group (P<0.01). However, the PR mRNA levels in the exposed group were statistically significance compared to the control group (P<0.05).【Conclusions】The findings suggest that some environmental pollutants existing in e-waste dismantling region may affect the health of local newborns, representing changes both in sera levels of thyroid hormones, sexual hormones and in mRNA expression of their receptors.PartⅣAssociations of hormones levels between pregnant women and newborns【Objective】To explore associations of hormones levels between pregnant women and newborns.【Methods】Spearman method was employed to analyze correlation between thyroid hormones and sexual hormones in maternal sera and in blood from cord.【Results】Positive correlation existed between FT4, TSH, E2, TSH in maternal sera and those in cord blood, between FT4 and FT3 in cord blood, between E2 and P in maternal sera, as well as the correlation between HPL in maternal sera , GH in cord blood and weight of newborns.(P < 0.05).【Conclusions】The findings suggest that the change of endocrine system of local parturient women may have influence on endocrine system of newborns.PartⅤEvaluated the biological effects of pollutants from the e-waste induced oxidative stress in pregnant women and newborns【Objective】To evaluate the biological effects of pollutants from the e-waste induced oxidative stress in pregnant women and newborns.【Methods】Levels of malondialdehyd (MDA), glutathione peroxidase (GSH-PX) and superoxide dismutase (SOD) activity were anayzed using the commercial kits. 【Results】In placentas and umbilical cords , the contents of MDA in exposed group is higher than control group(P <0.01), and activity of SOD is lower than control group(P <0.01, P <0.05). The activity of GSH-PX in placentas and umbilical cords is lower than control group(P <0.01). In the studied population, a positive correlation between the sera MDA, SOD, GSH-PX levels and the MDA, SOD, GSH-PX levels in tissues were observed, espectively (P <0.05).【Conclusions】The pollutants from the e-waste dismantling site may induce oxidative stress reactions in pregnant women and newborns.To sum up, e-waste pollution existing in e-waste dismantling region may affect local residents'endocrine system. Results from our research suggest that improper disposal of e-waste has affected local residents'sera levels of thyroid hormones and sexual hormones and corresponding hormone receptors mRNA levels, as well as a may induce oxidative stress reactions.Therefore, it is of great scientific significance to acquire further knowledge about PBDEs toxic mechanism, as well as to establish early-stage alarm system about the residents from e-waste pollution region.