Bioaccumulation of trace metals in aquatic food web. A case study, Liaodong Bay, NE China.

The recently developed modelling tool MERLIN-Expo was applied to support the exposure assessment of an aquatic food web to trace metals in a coastal environment. The exposure scenario, built on the data from Daliao River estuary in the Liaodong Bay (Bohai Sea, China), affected by long-term and large-scale industrial activities as well as rapid urbanization in Liao River watershed, represents an interesting case-study for ecological exposure modelling due to the availability of local data on metal concentrations in water and sediment. The bioaccumulation of selected trace metals in aquatic organisms was modelled and compared with field data from local aquatic organisms. Both model results and experimental data demonstrated that As, Cd, Cu, Ni, Pb and Zn, out of examined metals, were accumulated most abundantly by invertebrates and less by higher trophic level species. The body parts of the sampled animals with the highest measured concentration of metals were predominantly muscles, intestine and liver and fish skin in the case of Cr. The Morris and extended Fourier Analysis (EFAST) were used to account for variability in selected parameters of the bioaccumulation model. Food assimilation efficiency and slopes and intercepts of two sub-models for calculating metal specific BCFs (BCFmetal-exposure concentration) and fish weight (Weightfish-Lengthfish) were identified as the most influential parameters on ecological exposure to selected metals.

Multi-criteria decision analysis applied to harmful algal bloom management: A case study.

Harmful algal blooms (HABs) have received greater attention in recent years due to an increase in the frequency of outbreaks and a growing potential for blooms to exact considerable economic losses and negatively impact ecosystem health. Human activity has been shown to intensify HAB outbreaks through increased eutrophication, elevated local air and water temperatures, disturbance of the thermal stratification of lakes, and modification of local hydrology. With the advent of new remediation technologies and a better understanding of the ecological factors affecting HABs, mitigating the adverse effects of HABs has become more feasible than ever before but still requires balancing mitigation efficiency, environmental impacts, costs, and stakeholder needs. In the present paper, we discuss potential HAB management solutions and propose using a Multi-Criteria Decision Analysis (MCDA) framework to analyze the perspectives and priorities of various stakeholders as they pertain to 4 major considerations for HAB mitigation: human health, environmental impact, social impact, and technical feasibility. A hypothetical case study of an HAB-affected lake is used to demonstrate how stakeholders may prioritize HAB management alternatives within the MCDA framework. Integr Environ Assess Manag 2017;13:631-639. © 2016 SETAC.

Modelling ecological and human exposure to POPs in Venice lagoon - Part II: Quantitative uncertainty and sensitivity analysis in coupled exposure models.

The study is focused on applying uncertainty and sensitivity analysis to support the application and evaluation of large exposure models where a significant number of parameters and complex exposure scenarios might be involved. The recently developed MERLIN-Expo exposure modelling tool was applied to probabilistically assess the ecological and human exposure to PCB 126 and 2,3,7,8-TCDD in the Venice lagoon (Italy). The 'Phytoplankton', 'Aquatic Invertebrate', 'Fish', 'Human intake' and PBPK models available in MERLIN-Expo library were integrated to create a specific food web to dynamically simulate bioaccumulation in various aquatic species and in the human body over individual lifetimes from 1932 until 1998. MERLIN-Expo is a high tier exposure modelling tool allowing propagation of uncertainty on the model predictions through Monte Carlo simulation. Uncertainty in model output can be further apportioned between parameters by applying built-in sensitivity analysis tools. In this study, uncertainty has been extensively addressed in the distribution functions to describe the data input and the effect on model results by applying sensitivity analysis techniques (screening Morris method, regression analysis, and variance-based method EFAST). In the exposure scenario developed for the Lagoon of Venice, the concentrations of 2,3,7,8-TCDD and PCB 126 in human blood turned out to be mainly influenced by a combination of parameters (half-lives of the chemicals, body weight variability, lipid fraction, food assimilation efficiency), physiological processes (uptake/elimination rates), environmental exposure concentrations (sediment, water, food) and eating behaviours (amount of food eaten). In conclusion, this case study demonstrated feasibility of MERLIN-Expo to be successfully employed in integrated, high tier exposure assessment.