Trends of PCB concentrations in Lake Michigan coho and chinook salmon, 1975–2010

The manufacture and use of polychlorinated biphenyls (PCBs) was banned in the United States in 1977 after it was determined that these compounds adversely affect animals and humans. The Wisconsin Department of Natural Resources has quantified total PCB concentrations in Lake Michigan chinook (n = 765) and coho (n = 393) salmon (Oncorhynchus tshawytscha and Oncorhynchus kisutch, respectively) filets since 1975. We analyzed these data to estimate trends in PCB concentrations in these fish (1975–2010). We used generalized linear models with a gamma error distribution and log link fit to the untransformed concentrations. Trend patterns were examined using graphical smoothing and generalized additive models. We identified a candidate set of models that included time trend and other predictor variables. Using the Akaike Information Criterion to select among models we found the best models for both species included piecewise linear time trends, total body length, % lipid, and collection season as predictor variables. The intersection of the two trends was 1985 for chinook salmon and 1984 for coho salmon. PCB concentrations in both species increased with body length and % lipid, and were higher for individuals caught in the fall. Our data reveals a dramatic decline in PCB concentrations of − 16.7% and − 23.9% per year for chinook and coho, respectively, up until the intersection year likely reflecting implementation of restrictions on Aroclor-based PCBs. After the intersection year to 2010, PCB concentrations declined at an annual rate of − 4.0% (95% CI: − 4.4% to − 3.6%) and − 2.6% (95% CI: − 3.3% to − 1.9%) for chinook and coho, respectively.     

Comprehensive assessment of legacy organic contaminants and trends in lake trout from Cayuga Lake,New York: 2011–2017

A seven-year assessment of lake trout contaminants and statistical trend modeling was conducted on Cayuga Lake, New York as the reference monitoring site for the USEPA Great Lakes Fish Monitoring and Surveillance Program (GLFMSP). In all, over 200 individual compounds including polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), organochlorine pesticides (OCPs), polychlorinated napthalenes (PCNs), polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) were monitored for the 2011–2017 study period. Legacy contaminants such as PCBs, OCPs, and PBDEs dominate the whole-fish lake trout contaminant profile in the 24–147 ng/g mean concentration range. Total dioxin-like contaminants monitored included PCDD/Fs, CP-PCBs, and PCNs with a mean concentration range of 2.0–516 pg/g. TEQ concentrations for the dioxin-like compounds ranged between 0.3 and 5.3 pg-TEQ/g, and total TEQ averaged 7.2 pg-TEQ/g for whole-fish lake trout. Contaminant trends were modeled using log-linear correlations for both whole-fish lake trout and lake trout eggs. All select compounds modeled for whole-fish lake trout showed significant decreases (average ?53.4%) over the study period. Tissue residue guidelines for the protection of wildlife were uniformly exceeded for both mammals and birds based on mean 2011–2017 total TEQ concentrations measured. All lake trout skin-on fillets from Cayuga Lake analyzed exceed the USEPA human health screening value of 0.15 pg-TEQ/g-ww. Whole-fish lake trout from Cayuga Lake have significantly lower mean total TEQs (6.5 pg-TEQ/g) as compared with the average total TEQ in the Great Lakes (range: 21.9–50.8 pg-TEQ/g) (U = 10.000, p < 0.001), although rates of contaminant decline, contaminant ratios, and half-life (t_1/2) are comparable.     

Response to Late developers and the inequity of “equitable utilization” and the harm of “do no harm” by Kai Wegerich and Oliver Olsson,Water International, 35 (6), 707–717 (November 2010)

Abstract

A strategy is presented for predicting impacts of future climate change on water supply capabilities, which is based on using output from a general circulation model (GCM) developed by the Canadian Center for Climate Modeling and Analysis (CCCma) with a watershed hydrology model and a river/reservoir system management model. The GCM output was used to adjust input to a watershed hydrology model in order to predict the corresponding impacts on streamflows. Output from the watershed model was used to adjust naturalized streamflows in a river/reservoir system management model in order to determine the corresponding impacts on water supply reliabilities. The methodology was applied in an investigation of capabilities for supplying water to the City of Houston and other users in the San Jacinto River Basin of Texas. Historical versus 2040 to 2059 climate scenarios were compared. Study results indicate that long-term mean streamflows under 2040 to 2059 climate conditions were higher than under historical climate due to significant increases in floods and other high flows. However, flows were lower for the future climate scenario during periods of normal and low flows. Seasonal variations in flows were greater with the future climate scenario than the historical climate. Reservoir storage fluctuations increase under future climate. Due to relatively large storage capacities, reliabilities for water supply diversions were improved somewhat under future climate conditions.