No abstract

h i g h l i g h t sWe took 8 sediment cores and 27 ponar grabs from Lake Michigan in 2010. Samples were extracted for total fluorine, extractable fluorine and 25 PFCs. PFOS and PFOA are the predominant PFCs in sediment cores. PFBS and PFBA are appearing in upper sections at concentrations similar to PFOS and PFOA. TF and EOF concentrations are orders of magnitude higher than PFCs. a r t i c l e i n f o were measured in eight dated cores of sediment taken along with 27 surface sediments from Lake Michigan in 2010. Based on rates of sedimentation, total concentrations of PFCs ( P PFCs) reached a maximum in the later 1990s and early 2000s. This result is consistent with rapid changes in production and subsequent sedimentation. Perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) are still the predominant PFCs in the cores, but in surface sediments, concentrations of perfluorobutane sulfonate (PFBS) and perfluorobutanoic acid (PFBA) are now occurring at concentrations comparable to those of PFOS and PFOA. This observation is consistent with shifts in patterns of production and use in the US and Canada. Concentrations of TF in sediments were greater than those of EOF. This result is consistent with a larger proportion of un-extractable fluorinated material in both surface sediments and in cores.

-Concentrations of 14 organophosphorus insecticides (OPs) were measured in Apis mellifera L. (European honeybee) and hive matrices (honey and bee bread). Samples were collected from seven randomly selected colonies in central Saskatchewan during the summer of 2013. LC-MS/MS was used to identify and quantify individual OP by use of a modified quick easy cheap effective rugged safe (QuEChERS) method. Diazinon, dimethoate, and chlorpyrifos-oxon were the only OPs detected in honey with mean concentrations of 0.3, 1.5, and 0.2 ng/g, wet mass (wm), respectively. Fenamiphos, chlorpyrifos, and chlorpyrifos methyl were the only OPs detected in bee bread, with mean concentrations of 0.4, 2.7, and 15.8 ng/g, wm, respectively, while ethoprop, malathion, and dichlorvos were the only OPs detected in bees with mean concentrations of 1.4, 3.7, and 889.2 ng/g, wm, respectively. Total hazard quotients (HQs), based on lethality of bees exposed to OPs in honey and pollen consumed by bees ranged from 0.01 to 0.06 and based on lethality of bees from direct exposure to OPs ranged from 0.3 to 0.4 which suggests little hazard of OPs to Saskatchewan beehives.honey / OPs / risk assessment / agriculture / honeybees