BackgroundPolybrominated diphenyl ethers (PBDEs) are widely used in Western countries.ObjectivesBecause the prevalence of cryptorchidism appears to be increasing, we investigated whether exposure to PBDEs was associated with testicular maldescent.MethodsIn a prospective Danish–Finnish study, 1997–2001, all boys were examined for cryptorchidism. We analyzed whole placentas (for 95 cryptorchid/185 healthy boys) and individual breast milk samples (62/68) for 14 PBDEs and infant serum samples for gonadotropins, sex-hormone binding globulin, testosterone, and inhibin B.ResultsIn 86 placenta–milk pairs, placenta PBDE concentrations in fat were lower than in breast milk, and a larger number of congeners were nondetectable. There was no significant difference between boys with and without cryptorchidism for individual congeners, the sum of 5 most prevalent, or all 14 congeners. The concentration of PBDEs in breast milk was significantly higher in boys with cryptorchidism than in controls (sum of BDEs 47, 153, 99, 100, 28, 66, and 154: median, 4.16 vs. 3.16 ng/g fat; p < 0.007). There was a positive correlation between the sum of PBDEs and serum luteinizing hormone (p < 0.033). The sum of PBDEs in breast milk did not differ between Denmark and Finland (median, 3.52 vs. 3.44 ng/g fat), but significant differences in some individual congeners were found.ConclusionsTwo different proxies were used for prenatal PBDE exposure, and levels in breast milk, but not in placenta, showed an association with congenital cryptorchidism. Other environmental factors may contribute to cryptorchidism. Our observations are of concern because human exposure to PBDEs is high in some geographic areas.

No abstract

No abstract

Although these findings cannot be extrapolated to humans, MX should be studied as a candidate risk factor in the possible association between consumption of chlorinated drinking water and cancer in humans.

The availability of organic carbon is considered the key factor to regulate microbial regrowth in drinking water networks. However, boreal regions (northern Europe, Russia, and North America) contain a large amount of organic carbon in forests and peatlands. Therefore, natural waters (lakes, rivers, and groundwater) in the northern hemisphere generally have a high content of organic carbon. We found that microbial growth in drinking water in Finland is highly regulated not only by organic carbon but also by the availability of phosphorus. Microbial growth increased up to a phosphate concentration of 10 g of PO 4-P liter ؊1. Inorganic elements other than phosphorus did not affect microbial growth in drinking water. This observation offers novel possibilities to restrict microbial growth in water distribution systems by developing technologies to remove phosphorus efficiently from drinking water.