Different collector types for sampling deposition of polycyclic aromatic hydrocarbons--comparison of measurement results and their uncertainty

Different collector types, sample workup procedures and analysis methods to measure the deposition of polycyclic aromatic hydrocarbons (PAH) were tested and compared. Whilst sample workup and analysis methods did not influence the results of PAH deposition measurements, using different collector types changed the measured deposition rates of PAH significantly. The results obtained with a funnel-bottle collector showed the highest deposition rates and a low measurement uncertainty. The deposition rates obtained with the wet-only collectors were the lowest at industrial sites and under dry weather conditions. For the open-jar collectors the measurement uncertainty was high. Only at an industrial site with extremely high PAH deposition rates the results of open-jar collectors were comparable to those obtained with funnel-bottle collectors. Thus, if bulk deposition of PAH has to be measured, funnel-bottle combinations are proved to be the collectors of choice. These collectors were the only ones always fulfilling the requirements of European legislation.     

Inhibition of ethoxyresorufin-O-deethylase (EROD) activity in mixtures of 2,3,7,8-tetrachlorodibenzo-p-dioxin and polychlorinated biphenyls

Induction of ethoxyresorufin-O-deethylase (EROD) activity and porphyrin accumulation shows different structure-activity relationships for different polychlorinated biphenyls (PCBs) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Interactions between the two responses can strongly influence the induction and activity of EROD. The results support the conclusion that there are nonadditive interactions between nondioxin-like PCBs and dioxin-like compounds. The interaction between EROD activity and the porphyrin biosynthesis makes the prerequisite of additivity in the toxic equivalency factor concept for environmental mixtures highly spurious. Inhibition of EROD activity caused by non-dioxin like compounds could have a significant impact on the value of EROD activity as a biomarker in the present methods of risk assessment for these compounds.     

PHOSPHORUS LOSSES FROM CROPLAND AS AFFECTED BY TILLAGE SYSTEM AND FERTILIZER APPLICATION METHOD1

ABSTRACT: A rainfall simulator was used to study the effectiveness of no-till and fertilizer application method on reducing phosphorus (P) losses from agricultural lands. Simulated rainfall was applied to 12 experimental field plots, each 0.01 ha in size. The plots were divided into no-till and conventional tillage systems. Two fertilizer application methods, subsurface injection and surface application, were investigated for the two tillage systems. Phosphorus fertilizer was applied at a rate of 46 kg/ha, 24 to 48 hours before the start of rain simulation. Water samples were collected from the base of each plot and analyzed for sediment and P content. No-till was found to be very effective in reducing runoff and sediment losses. No-till reduced sediment loss and total runoff volume by 92 and 67 percent, respectively. Subsurface injection of fertilizer, as compared to surface application, reduced PO₄ losses by 39 percent for no-till and by 35 percent for conventional tillage. The effect of tillage system on PO₄ losses was not significant. Reductions in total-P (P_T) losses due to no-till compared to the conventional tillage system were 89 and 91 percent for surface application and subsurface injection methods, respectively. Averaged across all fertilizer treatments, an equivalent of 0.9 and 8.9 percent of the P applied to the plots were lost from the no-till and conventional tillage plots, respectively.     

Common Snapping Turtles (Chelydra serpentina) as a Source of Fecal Indicator Bacteria in Freshwater Systems1

Habersack, Mathew J., Theo A. Dillaha, and Charles Hagedorn, 2011. Common Snapping Turtles (Chelydra serpentina) as a Source of Fecal Indicator Bacteria in Freshwater Systems. Journal of the American Water Resources Association (JAWRA) 47(6):1255–1260. DOI: 10.1111/j.1752‐1688.2011.00572.x Abstract: The United States Total Maximum Daily Load program is required by Section 303(d) of the Clean Water Act to clean up waters that do not meet state water quality standards. While conducting research into the bacterial composition of semiaquatic mammal feces, the opportunity presented itself to quantify commonly used pathogen indicator bacteria in the gastrointestinal contents from an ectothermic (cold‐blooded) animal, the common snapping turtle. Indicator bacteria concentrations were on the order of 10⁶ CFU/g feces (dry weight basis). The estimated bacterial loadings from this study demonstrate that the common snapping turtle, if present in sufficient numbers, may contribute significant bacterial loadings to waterways and should be considered when developing bacterial Total Maximum Daily Loads and in other bacterial water quality assessments.