Summary 1.Shallow lakes are important components of the biosphere, but they are also highly vulnerable to damage from human activities in their catchments, such as nutrient pollution. They may also be particularly vulnerable to current warming trends. 2. Forty-eight tanks were used to create 3-m 3 mesocosms of shallow lake communities, in which the effects of warming by 4 ° C and regular nutrient loading at two levels relevant to current degrees of eutrophication were studied in the presence and absence of fish. 3. Warming changed concentrations of soluble phosphate, total nitrogen and conductivity, increased total plant biomass and decreased the amount of phytoplankton through shading by floating plants. Nutrient additions decreased total plant biomass but increased floating plant biomass. Nitrogen increase and warming increased floating plant biomass and decreased plant species richness. The plant community remained intact and did not switch to the turbid-water, phytoplankton-dominated community often predicted to be a consequence of global warming and eutrophication. 4. Synthesis and applications. Likely future temperature increase will exacerbate some, but not all symptoms of eutrophication in shallow lakes. Alone it will not cause a switch from plant-dominated to algal-dominated systems, but may result in nuisance growths of floating lemnids. Currently underplayed, nitrogen loading should be taken more seriously in the management of European freshwaters.

Perfluorinated compounds (PFCs) have been widely used in industrial applications and consumer products. Their persistent nature and potential health impacts are of concern. Given the high cost of collecting serum samples, this study is to understand whether we can quantify PFC serum concentrations using factors extracted from questionnaire responses and indirect measurements, and whether a single serum measurement can be used to classify an individual’s exposure over a one-year period. The study population included three demographic groups: young children (2–8 years old) (N=67), parents of young children (<55 years old) (N=90), and older adults (>55 years old) (N=59). PFC serum concentrations, house dust concentrations, and questionnaires were collected. The geometric mean of perfluorooctane sulfonic acid (PFOS) was highest for the older adults. In contrast, the geometric mean of perfluorooctanoic acid (PFOA) was highest for children. Serum concentrations of the parent and the child from the same family were moderately correlated (Spearman correlation (r)=0.26–0.79, p<0.05), indicating common sources within a family. For adults, age, having occupational exposure or having used fire extinguisher, frequencies of consuming butter/margarine, pork, canned meat entrées, tuna and white fish, freshwater fish, and whether they ate microwave popcorn were significantly positively associated with serum concentrations of individual PFCs. For children, residential dust concentrations, frequency of wearing waterproof clothes, frequency of having canned fish, hotdogs, chicken nuggets, French fries, and chips, and whether they ate microwave popcorn were significant positive predictors of individual PFC serum concentrations. In addition, the serum concentrations collected in a subset of young children (N=20) and the parents (N=42) one year later were strongly correlated (r=0.68–0.98, p<0.001) with the levels measured at the first visits, but showed a decreasing trend. Children had moderate correlation (r=0.43) between serum and dust concentrations of PFOS, indicating indoor sources contribute to exposure. In conclusion, besides food intake, occupational exposure, consumer product use, and exposure to residential dust contribute to PFC exposure. The downward temporal trend of serum concentrations reflects the reduction of PFCs use in recent years while the year-to-year correlation indicates that a single serum measurement could be an estimate of exposure relative to the population for a one-year period in epidemiology studies.

Low levels of pharmaceutical compounds have been detected in aquatic environments worldwide, but their human and ecological health risks associated with low dose environmental exposure is largely unknown due to the large number of these compounds and a lack of information. Therefore prioritization and ranking methods are needed for screening target compounds for research and risk assessment. Previous efforts to rank pharmaceutical compounds have often focused on occurrence data and have paid less attention to removal mechanisms such as human metabolism. This study proposes a simple prioritization approach based on number of prescriptions and toxicity information, accounting for metabolism and wastewater treatment removal, and can be applied to unmeasured compounds. The approach was performed on the 200 most-prescribed drugs in the U.S. in 2009. Our results showed that under-studied compounds such as levothyroxine and montelukast sodium received the highest scores, suggesting the importance of removal mechanisms in influencing the ranking, and the need for future environmental research to include other less-studied but potentially harmful pharmaceutical compounds.

Since the 2001 U.S. federally mandated phase-out of residential uses of organophosphates (OPs), use of and potential for human exposure to pyrethroids in the indoor residential environment has increased. We report concentrations of common pyrethroids, pyrethroid metabolites, and chlorpyrifos in floor wipes, and urinary concentrations of pyrethroid metabolites and 3,5,6-trichloro-2-pyridinol (TCPy) in samples collected in 2007-2009 from 90 northern California families as part of the Study of Use of Products and Exposure Related Behavior (SUPERB). Correlation and regression analyses examined associations between floor wipe and urine sample concentrations. The most frequently detected urinary metabolites were TCPy (64.7%, median concentration of 1.47 ng/mL) and 3-phenoxybenzoic acid (3PBA) (62.4%, 0.79 ng/mL). Compared to the National Health and Nutrition Examination Survey (NHANES) 2001-2002 general U.S. population, this population had substantially higher pyrethroid metabolite and lower TCPy urinary concentrations. This may be related to the increased residential use of pyrethroids after the phase-out of OPs. Chlorpyrifos (98.7%), cis- and trans-permethrin (97.5%), bifenthrin (59.3%), and 3PBA (98.7%) were frequently detected in the floor wipes. Floor wipe concentrations for pyrethroid insecticides were found to be significant predictors of child creatinine-adjusted urinary metabolite concentrations (log-log regression coefficients ranging from 0.26 to 0.29; p < 0.05) suggesting that indoor residential exposure to pyrethroid insecticides is an important exposure route for children.