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Number-average moleculsr weights bf poly(ethylene oxide) (PEO) are generally determined from changes in solvent colligative properties, viscoeity relationships, or by terminal hydroxyl analysis. It has now been established that good estimate of their molecular weights can be obtained from simple measurements of refractive index at any reasonable temperature above the softening range.A aeries of PEO polymers having number-average molecular weights, M,, from -300 to -20,000 were obtained and their refractive indices measured at 75 f 0.02"C. with a Valentine Improved Precision Model 450A refwtometer. Values of M, were determined from end-group hydroxyl by acetylation.It is The results are given in Table I.

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Foraging aggregations of east Pacific green sea turtles (Chelonia mydas) inhabit the Seal Beach National Wildlife Refuge (SBNWR) and San Diego Bay (SDB), two habitats in southern California, USA, located near urbanized areas. Both juvenile and adult green turtles forage in these areas and exhibit high site fidelity, which potentially exposes green turtles to anthropogenic contaminants. We assessed 21 trace metals (TM) bioaccumulated in green turtle scute and red blood cell (RBC) samples collected from SBNWR (n = 16 turtles) and SDB (n = 20 turtles) using acid digestion and inductively coupled plasma mass spectrometry. Principal component analyses of TM composition indicate that SBNWR and SDB turtles have location-specific contaminant signatures, characterized by differences in cadmium and selenium concentrations: SBNWR turtles had significantly more cadmium and selenium in RBC and more selenium in scute samples, than SDB turtles. Cadmium and selenium concentrations in RBC had a strong positive relationship, regardless of location. SBNWR turtles had higher selenium in RBCs than previously measured in other green turtle populations globally. Due to different retention times in blood vs. scute, these results suggest that SBNWR turtles have high long-and short-term selenium exposure. Turtles