Association of placenta organotin concentrations with growth and ponderal index in 110 newborn boys from Finland during the first 18 months of life: a cohort study.

BACKGROUND: Humans are exposed to tributyltin (TBT), previously used as an antifouling paint in ships, mainly through fish consumption. As TBT is a known obesogen, we studied the association of placenta TBT and other organotin compounds (OTCs) with ponderal index (PI) and growth during the first 18 months of life in boys. METHODS: In a prospective Finnish study, 110 placenta samples were collected from mothers of boys born in 1997-1999 with (n = 55) and without (n = 55) cryptorchidism. To account for the original study design, linear regression, weighted for sampling fractions of boys with (121/55) and without (5677/55) cryptorchidism from the total cohort, was used to study the association between placenta OTCs and children's weight, length, growth rates and PI up to 18 months of age. RESULTS: Placenta TBT concentrations were above the limit of quantification (LOQ) in 99% of the samples. However, monobutyltin (MBT), dibutyltin (DBT) and triphenyltin (TPhT) concentrations were below LOQ in 90%, 35% and 57% of samples, respectively. Placenta TBT was positively associated (p = 0.024) with weight gain during the first three months of life, but no other significant associations were observed for weight or length gain. Also, no significant associations between placenta OTC concentrations and child length, weight or PI at any time point were found. CONCLUSIONS: We observed a trend towards higher weight gain from birth to 3 months of age with increasing placenta TBT concentration. These results should be interpreted with caution because obesogenic effects in animal experiments were seen after in-utero TBT exposures to doses that were orders of magnitude higher. Also the number of study subjects included in this study was limited.

Association of placenta organotin concentrations with congenital cryptorchidism and reproductive hormone levels in 280 newborn boys from Denmark and Finland.

STUDY QUESTION: Is the placental burden of organotin compounds (OTCs) associated with congenital cryptorchidism in infant offspring from Finland and Denmark? SUMMARY ANSWER: Increasing concentrations of OTCs had a negative association with cryptorchidism in Finland, whereas a positive association was found in Denmark. WHAT IS KNOWN ALREADY: The rapid increase in the prevalence of cryptorchidism suggests that environmental factors, such as endocrine disruptors, may be involved. OTCs are endocrine disruptors at very low concentrations due to activation of the retinoid X receptor (RXR). STUDY DESIGN, SIZE, DURATION: Between the years 1997 and 2001, placentas from mothers of cryptorchid boys and from healthy controls were collected from Denmark (39 cases, 129 controls) and Finland (56 cases, 56 controls). In Denmark 33 and 6 boys, and in Finland 22 and 34 boys had mild or severe cryptorchidism, respectively. The association between concentrations of four OTCs [monobutyltin (MBT), dibutyltin (DBT), tributyltin (TBT) and triphenyltin (TPhT)] and case-control status was estimated. PARTICIPANTS/MATERIALS, SETTING, METHODS: In both countries, placenta samples were selected from larger cohorts. In Finland placenta samples were collected from boys with cryptorchidism at birth and matched controls (nested case-control design). Matching criteria were parity, maternal smoking (yes/no), diabetes (yes/no), gestational age (±7 days) and date of birth (±14 days). Numbers of controls per case was 1. In Denmark, all available placentas from cryptorchid boys were chosen and control placentas were selected randomly from the total Danish cohort (case-cohort design). The average number of controls per case was 3.3. OTCs in placenta samples were analysed with liquid extraction, ethylation and gas chromatography-mass spectrometry determination and coded by country-specific tertiles. MAIN RESULTS AND THE ROLE OF CHANCE: Generally, the concentrations of OTCs were very low. For most analytes, a large proportion of samples (29-96% depending on the country and case-control status) had OTC concentrations below the limit of quantification (LOQ). As an exception, the concentration of TBT was >LOQ in 99% of Finnish placentas. The mean concentrations of DBT and TBT were 1.5 and 7 times higher in Finland than in Denmark, respectively. For DBT in Danish placentas, the odds ratio (OR) for cryptorchidism in the second tertile (0.10-0.14 ng/g) when compared with the first tertile (<0.10 ng/g,

Blood concentration of methylmercury in relation to food consumption.

OBJECTIVE: Dietary fish is the main source of methylmercury (MeHg) for man, and fish consumption has been used as a measure of MeHg exposure. However, other dietary sources of exposure exist and MeHg metabolism may also be modified by nutritional factors. The aim of the present study was to examine the association between blood MeHg concentration and consumption of different foods in a Finnish population with high fish consumption. DESIGN: Blood samples, a detailed FFQ and additional frequency data on fish consumption were collected. MeHg was analysed from whole blood by the isotope dilution method with high-resolution MS. The consumption of different foods was calculated by MeHg quartiles and tested for linear trend. SETTING: Finnish southern and south-western coast of the Baltic Sea. SUBJECTS: Two hundred and ninety-nine professional fishermen, their spouses and other family members. RESULTS: Mean (range) blood MeHg concentration was 4·6 (0·21-22) µg/l among men and 2·8 (<0·15-20) µg/l among women. Fish had the strongest positive association with MeHg (P for linear trend <0·001 among both men and women). Among men, positive associations were also observed for fruit vegetables, wheat and wine. Among women, positive associations were observed for root vegetables, legumes, potato and game, but adjustment for fish consumption attenuated these trends. CONCLUSIONS: The study shows that, besides fish, MeHg may have other dietary sources that should be taken into account in risk assessment studies. Due to the observed high blood MeHg concentration, a thorough exposure assessment among the general Finnish population is recommended.

Persistent organic pollutants in two Finnish watercourses: levels, congener profiles and source estimation by mussel incubation.

Mussel incubation was used to compare two Finnish watercourses, which have been contaminated by effluents from pulp mills and are known to be polluted with polychlorinated biphenyls (PCBs). Lake mussels (Anodonta Piscinalis) incubated in 1998 and 2004 in the rivers Kymijoki and Vuoksi were analysed for PCBs and polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), naphthalenes (PCNs), diphenyl ethers (PCDEs), hydroxy diphenyl ethers (HO-PCDEs), methoxy diphenyl ethers (MeO-PCDEs), and polybrominated diphenyl ethers (PBDEs). The contamination of the River Kymijoki, which descends to the Baltic Sea, proved significantly greater than that of the River Vuoksi, with no decreasing apparent trend, except for the PBDEs. The River Vuoksi represented more a background area compared to the River Kymijoki, excluding the PCBs. The concentration of the PCDD/PCDFs in the Kymijoki mussels exceeded the EU's maximum permissible level for PCDD/PCDFs in foodstuffs (4 pg g(-1) fresh weight). Analyses of perfluorooctanesulphonate and perfluorooctanoate in the mussels incubated in 2005 and 2006 in the River Kymijoki revealed no significant contamination of the river with these compounds. Comparison of the data of the mussels with that of sediments and commercial formulations showed that the past manufacture of a chlorophenol-based wood preservative has remained a significant source of the PCDD/PCDFs, HO-PCDEs and PCDEs in the River Kymijoki. PCB formulations are believed to represent the major sources of the PCBs and PCNs in both watercourses, though situation in the River Kymijoki had been influenced by a chlor-alkali plant. Municipal wastewaters are believed to represent the major source of the PBDEs.

Organotin intake through fish consumption in Finland.

BACKGROUND: Organotin compounds (OTCs) are a large class of synthetic chemicals with widely varying properties. Due to their potential adverse health effects, their use has been restricted in many countries. Humans are exposed to OTCs mostly through fish consumption. OBJECTIVES: The aim of this study was to describe OTC exposure through fish consumption and to assess the associated potential health risks in a Finnish population. METHODS: An extensive sampling of Finnish domestic fish was carried out in the Baltic Sea and freshwater areas in 2005-2007. In addition, samples of imported seafood were collected in 2008. The chemical analysis was performed in an accredited testing laboratory during 2005-2008. Average daily intake of the sum of dibutyltin (DBT), tributyltin (TBT), triphenyltin (TPhT) and dioctyltin (DOT) (SigmaOTCs) for the Finnish population was calculated on the basis of the measured concentrations and fish consumption rates. RESULTS: The average daily intake of SigmaOTCs through fish consumption was 3.2ng/kgbwday(-1), which is 1.3% from the Tolerable Daily Intake (TDI) of 250ng/kgbwday(-1) set by the European Food Safety Authority. In total, domestic wild fish accounted for 61% of the SigmaOTC intake, while the intake through domestic farmed fish was 4.0% and the intake through imported fish was 35%. The most important species were domestic perch and imported salmon and rainbow trout. CONCLUSIONS: The Finnish consumers are not likely to exceed the threshold level for adverse health effects due to OTC intake through fish consumption.

Concentrations of organotin compounds in various fish species in the Finnish lake waters and Finnish coast of the Baltic Sea.

Organotin compounds (OTCs) leaching from the antifouling paints used in boats and ships have contaminated many water areas worldwide. The purpose of this study was to obtain a general view of the organotin contamination in fish in Finnish lake areas and Finnish coast of the Baltic Sea using perch as the main indicator species. Perch sampling covered areas presumed as less contaminated and areas suspected as more contaminated. Besides perch, 12 other species were sampled from sites presumed as less contaminated. OTCs measured were mono-, di- and tributyltin, mono-, di-, and triphenyltin and dioctyltin. The sum concentration of OTCs (SigmaOTCs) in perch in the least contaminated areas of the Baltic Sea were around 20 ng/g fresh weight (fw) and less than 10 ng/g fw in lake areas. In heavily contaminated areas of the Baltic Sea 150-500 ng/g fw in perch were detected. In lake areas the maximum SigmaOTCs in perch was only 30 ng/g fw. With regard to the other species in the Baltic Sea, salmon, sprat, flounder, whitefish, vendace and lamprey contained low concentrations (SigmaOTCs mainly less than 20 ng/g fw), whereas in pike, pike-perch, burbot and bream concentrations were higher. SigmaOTCs in lake fish were generally lower than in the Baltic Sea. In a distance gradient study, SigmaOTCs in perch decreased quickly from nearly 200 ng/g fw at a contaminated harbor area to 35 ng/g fw during a distance of 5 km. Further decrease was slower and reached 15 ng/g fw at 100 km. In a size dependence study triphenyltin showed better correlation with the fish length than tributyltin for all species studied, i.e. for perch (0.16 vs 0.26), pike-perch (0.13 vs 0.24) and roach (0.46 vs 0.80). High correlation for roach may be partly explained by smaller number of samples collected and small length range.

Health impacts of long-term exposure to disinfection by-products in drinking water in Europe: HIWATE.

There appears to be very good epidemiological evidence for a relationship between chlorination by-products, as measured by trihalomethanes (THMs), in drinking water and bladder cancer, but the evidence for other cancers, including colorectal cancer appears to be inconclusive and inconsistent. There appears to be some evidence for a relationship between chlorination by-products, as measured by THMs, and small for gestational age (SGA)/intrauterine growth retardation (IUGR) and preterm delivery, but evidence for other outcomes such as low birth weight (LBW), stillbirth, congenital anomalies and semen quality appears to be inconclusive and inconsistent.The overall aim of the HIWATE study is to investigate potential human health risks (e.g. bladder and colorectal cancer, premature births, SGA, semen quality, stillbirth, congenital anomalies) associated with long-term exposure to low levels of disinfectants (such as chlorine) and DBPs occurring in water for human consumption and use in the food industry. The study will comprise risk-benefit analyses including quantitative assessments of risk associated with microbial contamination of drinking water versus chemical risk and will compare alternative treatment options. The outcome will be improved risk assessment and better information for risk management. The work is divided into different topics (exposure assessment, epidemiology, risk assessment and management) and studies.

Maternal smoking during pregnancy and testicular cancer in the sons: a nested case-control study and a meta-analysis.

Some large ecological studies have noted a significant association of testicular cancer (TC) with maternal smoking during pregnancy, while several more controlled studies have been negative. It has been difficult to obtain reliable data on exposure because of the long lag time to cancer diagnosis. We performed a case-control study nested within Finnish, Swedish and Icelandic maternity cohorts exploiting early pregnancy serum samples to evaluate the role of maternal smoking in the risk of TC in the offspring. After reviewing the literature, we also performed a meta-analysis of published studies. For each index mother of the TC patient, three to nine matched control mothers with a cancer-free son born at the same time as the TC case were identified within each cohort. First trimester sera were retrieved from the 70 index mothers and 519 control mothers and were tested for cotinine level by a novel HPLC-MS-MS method developed. No statistically significant association between maternal cotinine level and risk of TC in the offspring was found (OR 0.68; 95% CI 0.35, 1.34). This is the first study based on individual exposure measurements. Its results agree with our meta-analysis of seven previous epidemiological studies (total number of 2149 cases, 2762 controls) using indirect exposure assessment (OR 1.0; 95% CI 0.88, 1.12).

A simple and fast liquid-liquid extraction method for the determination of 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153) and 1,1-dichloro-2,2-bis(p-chlorophenyl)-ethylene (p,p'-DDE) from human serum for epidemiological studies on type 2 diabetes.

A simple and fast method is presented to be used for example in studies on the relationship between serum levels of persistent organic pollutants and type 2 diabetes mellitus. Method is based on liquid-liquid extraction and gas chromatography coupled with high-resolution mass spectrometry. In the sample pre-treatment special attention was paid to minimize the number of sample manipulation steps and the amounts of organic solvents needed. Compounds analyzed were 2,2',4,4',5,5'-hexachlorobiphenyl (PCB-153) and 1,1-dichloro-2,2-bis (p-chlorophenyl)-ethylene (p,p'-DDE), the major metabolite of DDT. The method included extraction and cleanup of 0.2ml of serum in a single test tube and subsequent analysis of the extract from 0.2ml final volume. Validation was conducted to explore the performance of the method. The limits of detection for p,p'-DDE and PCB-153 based on the standard deviation of the blank samples were 4.3 and 3.1pg/ml, respectively. Repeatability was less than 2.5% at three concentration levels tested and recovery from Certified Reference Material SRM 1589a was 84% for p,p'-DDE and 87% for PCB-153 of the certified values, respectively. Serum samples from the AMAP intercalibration round 2008-2 were also analyzed, and results were 101-116% of the assigned values. The presented method was used for an epidemiological study with more than 700 serum samples from a type 2 diabetes cohort from Sweden.

A decision framework for possible remediation of contaminated sediments in the River Kymijoki, Finland.

BACKGROUND, AIM, AND SCOPE: The paper describes the spatial contamination of the River Kymijoki, South-Eastern Finland, and the coastal region of the Gulf of Finland with PCDD/Fs and mercury. The findings of ecotoxicologial and human health studies are also reported, including environmental and human risk assessments. Sediments from the River Kymijoki, draining into the Gulf of Finland, have been heavily polluted by the pulp and paper industry and by chemical industries. A wood preservative, known as Ky-5, was manufactured in the upper reaches of the river between 1940 and 1984 causing severe pollution of river sediments with polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF). Moreover, the sediments have been polluted with mercury (Hg) from chlor-alkali production and the use of Hg as a slimicide in pulp and paper manufacturing. MATERIALS AND METHODS: An extensive sediment survey was conducted as well as sediment transport modeling, toxicity screening of sediment invertebrates, and a survey of contaminant bioaccumulation in invertebrates and fish. Studies on human exposure to PCDD/Fs and the possible effects on hypermineralization of teeth as well as an epidemiological study to reveal increased cancer risk were also conducted. An assessment of the ecological and human health risks with a null hypothesis (no remediation) was undertaken. RESULTS: The sediment survey revealed severe contamination of river and coastal sediments with PCDD/Fs and Hg. The total volume of contaminated sediments was estimated to reach 5x10(6) m3 and hot spots with extremely high concentrations (max 292,000 ng g(-1) or 1,060 ng I-TEQ g(-1) d.w.) were located immediately downstream from the pollution source (approximately 90,000 m3). Sediment contamination was accompanied by changes in benthic assemblages, but direct effects were masked by many factors. The fish showed only slightly elevated PCDD/F levels in muscle, but orders of magnitude higher in the liver compared with reference freshwater sites and the Baltic Sea. The concentrations in human fat did not reveal high human exposure in the Kymijoki area in general and was lower than in sea fishermen. The relative risk for total cancer among farmers was marginally higher (RR=1.13) among those living close to the river, compared with farmers living further away, and the possibility of increased cancer risk cannot be ruled out. A conservative risk assessment revealed that the present probability of exceeding the WHO upper exposure limit of 4 pg WHO-TEQ kg(-1) d(-1) for PCDD/Fs and DL-PCBs was 6%. The probability of exceeding the WHO limit value of 0.23 mug kg(-1) d(-1) for methyl mercury was estimated to be notably higher at 62%. Based on these studies and the estimated risks connected with different remediation techniques a general remediation plan with cost benefit analysis was generated for several sub-regions in the river. Dredging, on-site treatment, and a close disposal of the most contaminated sediments (90,000 m3) was suggested as the first phase of the remediation. The decision regarding the start of remediation will be made during autumn 2008. CONCLUSIONS: The sediments in the River Kymijoki are heavily polluted with PCDD/Fs and mercury from earlier chlorophenol, chlor-alkali, and pulp and paper manufacturing. A continuous transport of contaminants is taking place to the Gulf of Finland in the Baltic Sea. The highly increased PCDD/F and Hg levels in river sediments pose an ecotoxicological risk to benthic fauna, to fish-eating predators and probably to human health. The risks posed by mercury exceed those from PCDD/Fs and need to be evaluated for (former) chlor-alkali sites and other mercury releasing industries as one basis for remediation decision making. RECOMMENDATIONS AND PERSPECTIVES: The studies form the basis of a risk management strategy and a plan for possible remediation of contaminated sediments currently under consideration in the Southeast Finland Regional Environment Centre. It is recommended that a detailed restoration plan for the most seriously contaminated areas should be undertaken. Based on current knowledge, the restoration of the whole river is not feasible, considering the current risk caused by the contaminated sediment in the river and the costs of an extensive restoration project. The experiences gained in the present case should be utilized in the evaluation of PCDD/F- and mercury-contaminated sites in other countries. The case demonstrates that the historic reservoirs are of contemporary relevance and should be addressed, e.g., in the national implementation plans of the Stockholm Convention.

Contamination of River Kymijoki sediments with polychlorinated dibenzo-p-dioxins, dibenzofurans and mercury and their transport to the Gulf of Finland in the Baltic Sea.

Kymijoki, the fourth largest river in Finland, has been heavily polluted by pulp mill effluents as well as the chemical industry. Up to 24,000 ton of wood preservative, chlorophenol known as Ky-5, was manufactured in the upper reaches of the river, an unknown amount of which was discharged into the river between 1940 and 1984. Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) occurred as impurities in the final Ky-5 product. The PCDD/F concentrations and burden in the river sediments were studied and the transport of PCDD/Fs from contaminated sites downstream and into the Gulf of Finland in the Baltic Sea was estimated. More than 190 sediment cores were sampled to estimate the volume of contaminated sediments and the total PCDD/F burden. The transport of PCDD/Fs was estimated using sediment traps placed at several sites. The survey revealed that sediments in the river were heavily polluted by PCDD/Fs, the main toxic congener being 1,2,3,4,6,7,8-heptachlorodibenzofuran, a major contaminant in the Ky-5 product. The mean total concentration at the most polluted river site downstream from the main source was 42000 microg kg(-1) d.w. (106 microg I-TEQ kg(-1)). The elevated concentrations in the coastal region and the present estimated transport from the River Kymijoki confirm earlier assessments that the river is a major source of PCDD/F for the Gulf of Finland.

Mortality in a cohort with high fish consumption.

BACKGROUND: Our aim was to assess the mortality of fishermen and fishermen's wives in Finland, presuming that the mortality reflects their high consumption of contaminated fish. METHODS: All Finnish fishermen, registered since 1980, were identified from the Professional Fishermen Register (N = 6410), and the fishermen's wives from the national population register (N = 4260). The cohorts were individually linked with cause-of-death data until 2005 at Statistics Finland. The follow-up started in the year after the first registration as a fisherman and at marriage (if later) for the wives. The standardized mortality ratios (SMRs) were calculated based on the national mortality rates. In addition, blood samples and food frequency questionnaire data were collected from a volunteer sample. RESULTS: The average fish consumption and serum concentrations of fish-derived fatty acids and environmental contaminants were higher among the fishermen and their wives than among the general population from the same region. The fishermen and their wives had lower mortality from all causes (SMR 0.78, 95% confidence interval (CI) 0.73-0.82, and 0.84, 0.76-0.93, respectively), and ischaemic heart diseases (0.73, 0.65-0.81, and 0.65, 0.50-0.83) than the general population. Mortality from cerebrovascular diseases and malignant neoplasms was decreased among the fishermen (0.67, 0.52-0.85, and 0.90, 0.80-1.01), but not among the wives. In addition, the fishermen's mortality from water transport accidents was extremely high (8.31, 5.65-11.79). CONCLUSIONS: The fishermen and their wives had lower mortality from many natural causes. The high intakes of environmental contaminants in fish were not seen as excess mortality.

Blood levels of organotin compounds and their relation to fish consumption in Finland.

The objective of this study was to measure the concentrations of organotin compounds in the whole blood of Finnish male fishermen (n=133), their wives (n=94), and other family members (n=73), and to investigate their associations with background variables. The concentrations were generally low, less than the limit of quantification (LOQ) for the vast majority of compounds and samples. Of the organotin compounds (mono-, di-, and tributyltin, mono-, di-, and triphenyltin, and dioctyltin), only triphenyltin was detected in more than just a few samples (in 37 of 300 samples, LOQ=0.04 ng/ml). These were mainly the samples of fishermen (26/37) and their wives (10/37). For statistical analysis, concentrations of triphenyltin were divided into two categories, LOQ. Of the different background variables, age and fish consumption contributed the most to the triphenyltin concentrations. When age and fish consumption (g/day) were divided into three categories, odds ratios comparing the highest with the lowest category were 3.88 for age (95% CI 1.36-11.09) and 3.48 for fish consumption (1.36-8.94), respectively. Compared with females, males had an odds ratio of 1.51 of having the concentration of triphenyltin >LOQ (0.72-3.14). To the best of our knowledge, this study confirmed for the first time with human samples that fish consumption can be associated with triphenyltin concentration in whole blood.

Organohalogen pollutants in herring from the northern Baltic Sea: concentrations, congener profiles and explanatory factors.

Organohalogen contaminants were investigated in Baltic herring caught from three catchment areas in the Baltic Sea, off the coasts of Finland. Pools of both small and large herring were analysed for polychlorinated biphenyls (PCB), dibenzo-p-dioxins, dibenzofurans, naphthalenes, camphenes (toxaphene), polybrominated diphenyl ethers and the pesticide DDT and its metabolites. PCB concentrations per fresh weight in small herring were at the same level in all catchment areas, i.e. the Bothnian Bay, the Bothnian Sea and the Gulf of Finland, revealing no hot spots and reflecting most likely long term emissions and atmospheric deposition. Differences in the levels and/or congener profiles of other contaminants between catchment areas may be explained by point sources. Similar concentrations in small and large herring in the Gulf of Finland were possibly due to their common nutrition. In the other areas, differences between small and large herring most likely reflected their different food sources.

Flame retardants in placenta and breast milk and cryptorchidism in newborn boys.

BACKGROUND: Polybrominated diphenyl ethers (PBDEs) are widely used in Western countries. OBJECTIVES: Because the prevalence of cryptorchidism appears to be increasing, we investigated whether exposure to PBDEs was associated with testicular maldescent. METHODS: In 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. RESULTS: In 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. CONCLUSIONS: Two 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.

Bioaccumulation, bioavailability and environmental fate of chlorophenol impurities, polychlorinated hydroxydiphenylethers and their methoxy analogues.

The bioaccumulation potential and environmental fate of polychlorinated hydroxydiphenyl ethers (HO-PCDEs; polychlorinated phenoxyphenols, PCPP), the major impurities of chlorophenol formulations and their methoxy analogues (MeO-PCDEs; polychlorinated methoxyanisoles, PCPAs) were investigated. Oligochaete worms (Lumbriculus variegatus) exposed to sediment spiked with a model substance of one HO-hexaCDE (4'-HO-PCDE 161) or its methoxy analogue (4'-MeO-PCDE 161) clearly accumulated the test compounds revealing the potential for environmental risk of HO-PCDEs and MeO-PCDEs. The HO-PCDE tested has earlier been reported as an abundant component in a Finnish chlorophenol formulation (Ky-5) and its methoxy analogue is recognized as an abundant MeO-PCDE in sawmill soil contaminated by the formulation. The occurrence of 4'-HO-PCDE 161 and its methoxy analogue among other HO-PCDEs and MeO-PCDEs in lake mussels (Anodonta piscinalis) incubated in a river contaminated via the manufacture of Ky-5 showed that these compounds are bioavailable and transported in the aquatic environment. Mussel comparison with sediment data pointed to a higher accumulation potential for MeO-PCDEs than for HO-PCDEs. The finding of HO-PCDEs in groundwater samples collected from a groundwater reservoir, which had been contaminated by chlorophenols, points to potential of HO-PCDEs for transport with water in soil.

Estimates of microbial quality and concentration of copper in distributed drinking water are highly dependent on sampling strategy.

The numbers of bacteria generally increase in distributed water. Often household pipelines or water fittings (e.g., taps) represent the most critical location for microbial growth in water distribution systems. According to the European Union drinking water directive, there should not be abnormal changes in the colony counts in water. We used a pilot distribution system to study the effects of water stagnation on drinking water microbial quality, concentration of copper and formation of biofilms with two commonly used pipeline materials in households; copper and plastic (polyethylene). Water stagnation for more than 4h significantly increased both the copper concentration and the number of bacteria in water. Heterotrophic plate counts were six times higher in PE pipes and ten times higher in copper pipes after 16 h of stagnation than after only 40 min stagnation. The increase in the heterotrophic plate counts was linear with time in both copper and plastic pipelines. In the distribution system, bacteria originated mainly from biofilms, because in laboratory tests with water, there was only minor growth of bacteria after 16 h stagnation. Our study indicates that water stagnation in the distribution system clearly affects microbial numbers and the concentration of copper in water, and should be considered when planning the sampling strategy for drinking water quality control in distribution systems.

Dietary intake of organotin compounds in Finland: a market-basket study.

The objective of this study was to estimate the intake of organic tin compounds from foodstuffs in a Finnish market basket. The study was conducted by collecting 13 market baskets from supermarkets and market places in the city of Kuopio, eastern Finland. Altogether 115 different food items were bought. In each basket, foodstuffs were mixed in proportion to their consumption and analysed by GC/MS for seven organic tin compounds (mono-, di-, and tributyltin, mono-, di-, and triphenyltin, and dioctyltin). Organotin compounds were detected in only four baskets, with the fish basket containing the largest number of different organotins. The European Food Safety Authority has established a tolerable daily intake of 250 ng kg(-1) body weight for the sum of dibutyltin, tributyltin, triphenyltin and dioctyltin. According to this study, the daily intake of these compounds was 2.47 ng kg(-1) body weight, of which 81% originated from the fish basket. This exposure is only 1% of the tolerable daily intake and poses negligible risk to the average consumer. However, for consumers eating large quantities of fish from contaminated areas, the intake may be much higher.

The effects of changing water flow velocity on the formation of biofilms and water quality in pilot distribution system consisting of copper or polyethylene pipes.

We studied the effects of flow velocity on the formation of biofilms and the concentration of bacteria in water in copper and plastic (polyethylene, PE) pipes. The formation of biofilms increased with the flow velocity of water. The increase in microbial numbers and contents of ATP was clearer in the PE pipes than in the copper pipes. This was also seen as increased consumption of microbial nutrients in the pipeline system. This indicates that the mass transfer of nutrients is in major role in the growth of biofilms. However, the increased biomass of biofilms did not affect microbial numbers in the water. Rapid changes in water flow rate resuspended biofilms and sediments which increased the concentrations of bacteria and copper in water. The disturbance caused by the changing water flow was also seen as an increase in the particle counts and water turbidity recorded with online instrumentation.

Polychlorinated dibenzo-p-dioxins, dibenzofurans, biphenyls, naphthalenes and polybrominated diphenyl ethers in the edible fish caught from the Baltic Sea and lakes in Finland.

A total of 156 fish composite samples were collected from five areas of the Baltic Sea and from three lakes and analysed for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs) and polybrominated diphenyl ethers (PBDEs). The European Union's maximum permissible level for PCDD/Fs, 4 pg WHO-TEQ/g fresh weight (fw), was exceeded in salmon, river lamprey and Baltic herring. In other species from the Baltic Sea, the 90th percentile was 3.42 pg WHO(PCDD/F)-TEQ/g fw. In the lake fish, the concentrations of PCDD/Fs, PCBs and PCNs were only 29-46% of those in the same species caught from the Baltic Sea, whereas the concentrations of PBDEs in the lake fish were as high as in the Baltic Sea fish. Dioxin-like PCBs contributed to the total dioxin-like toxicity of PCBs and PCDD/Fs by 49+/-12% in all the analysed samples.