Spatial and temporal variability of PCBs in Detroit River water assessed using a long term biomonitoring program.

An assessment of polychlorinated biphenyls (PCBs) in water of the Detroit River, North America, was performed using mussel biomonitoring data generated between 1996 and 2010. The study included a temporal monitoring program at six locations and an enhanced spatial survey performed during 2002. Mussels were transplanted at biomonitoring stations and collected after 21-226 d. A toxicokinetic model was used to perform steady state and control corrections followed by an equilibrium partitioning model to estimate bioavailable water concentrations of PCBs. Bioavailable water concentrations of PCBs were similar in magnitude and trends to dissolved water concentrations reported in previous studies using direct sampling approaches. PCB concentrations exhibited complex temporal patterns at the six biomonitoring stations with multi-year declines in PCB trajectories between 1996 and 2002 and less consistent trends occurring across stations in later years. Spatial patterns of PCBs during 2002 revealed significantly higher water contamination on the US side of the river (seasonal average mean ± standard error (SE) sum PCB concentration of 0.63 ± 0.11 ng L(-1)) compared to the Canadian side (mean ± SE sum PCB concentration of 0.09 ± 0.01 ng L(-1)). Spatial/temporal variability of bioavailable PCB concentrations was greatest between countries, followed by moderate variation across years and by river reach (upstream, midstream and downstream sections within a country) and lowest when comparing intra-seasonal variation.

Supplementation with bio-calcium from shells Pinctada maxima in postmenopausal women with decreased mineral bone density--pilot study.

INTRODUCTION: Treatment of osteoporosis, in addition to a specific antiresorptive or anabolic treatment, requires supplementation with calcium and vitamin D. Widespread cultivation of pearl shells has made pearls available for commercial use for a very reasonable price. The main chemical compound of pearls from shells Pinctada maxima is calcium-carbonate (CaCO3). Recently developed technologies applied in a micronisation process have provided increased gastrointestinal resorption of calcium, estimated at over 90% of calcium intake. OBJECTIVE: The paper is aimed at monitoring of efficacy and tolerance of six-month bio-calcium supplementation in postmenopausal women with reduced bone mineral density. METHODS: Group 1 (30 patients) received, three times a day, capsules of pearl powder from shells Pinctada maxima (it is equal to 260 mg of elementary calcium); group II (20 patients) received a daily dose of 500 mg inorganic CaCO3. Both groups received 666 IU of cholecalciferol per day. In all patients, bone mineral density (BMD) of the spine or hip, serum blood and urine levels of Ca, phosphates and alkaline phosphatase, were measured before and after six months of the treatment. RESULTS: Group I/Group II: average age 61.7/61.7 years; beginning of menopause: 48.32 /48 years; menopause duration 13.4/13.7 years; average body mass index 27.2/27 kg/m2. These two groups did not different significantly before supplementation. Six-month supplementation with CaCO3 of the biological origin led to the increase of BMD from 0.901 g/cm2 to 0.948 g/cm2 (p = 0.067), while BMD remained the same in the group supplemented with inorganic CaCO3 Gastrointestinal tolerability of bio-calcium was excellent, without any adverse events. CONCLUSION: These data could not strongly support the hypothesis of better efficacy of bio-calcium taking into account a small number of patients and a short follow-up period in this pilot study. Tolerance of CaCO3 of the biological origin was excellent and free of any adverse events. The results of laboratory values were within normal range.