No abstract available

[en] OAK 270 - Ground-Water Monitoring System for Multiple Sensors

No abstract available

[en] The original article has been published with some errors in tables. The corrected ones are given below.

No abstract available

[en] We quantified internal processes that supply methylmercury from hypolimnetic reducing zones to the upper waters of a Hg-contaminated lake, Onondaga Lake, NY, USA. Diffusive transport continuously supplied methylmercury to the epilimnion under summer stratification, while fall mixing resulted in a pulsed release of methylmercury to the upper mixed waters. These processes were the main internal sources of methylmercury to the epilimnion, and together almost equaled the total external supply. The wind-driven entrainment represented an additional stochastic internal supply of methylmercury of approximately 9% in 2006. Considering more than 15 years of data, we estimate 1.8 wind-driven events occur per year. The mass of methylmercury inputs to the epilimnion exceeded the measured increase, suggesting that loss processes are important in regulating methylmercury accumulation. The relative contribution of internal sources of methylmercury to the epilimnion has decreased in recent years, shifting the importance to the external inputs. Highlights: • Internal mercury cycling was equally important to external inputs in a polluted lake. • Diffusive mixing was a critical source of methylmercury under stratified conditions. • Entrainment-based transport of methylmercury detected under sustained wind conditions. • Lake-wide mixing provided the single largest internal input of MeHg to the epilimnion. -- Capsule: Internal cycling of legacy mercury deposits constitutes a substantial source of methylmercury to the epilimnion of a stratified polluted lake

[en] More than 2300 sediment pore water distribution coefficients (K_PCBids) of 93 polychlorinated biphenyls (PCBs) were measured and modeled from sediments from Indiana Harbor and Ship Canal. K_PCBids were calculated from previously reported bulk sediment values and newly analyzed pore water. PCBs in pore waters were measured using SPME PDMS-fiber and ∑PCB ranged from 41 to 1500 ng L⁻¹. The resulting K_PCBids were ∼1 log unit lower in comparison to other reported values. A simple model for the K_PCBid consisted of the product of the organic carbon fraction and the octanol–water partition coefficient and provided an excellent prediction for the measured values, with a mean square error of 0.09 ± 0.06. Although black carbon content is very high in these sediments and was expected to play an important role in the distribution of PCBs, no improvement was obtained when a two-carbon model was used. -- Highlights: •PCB sediment-pore water distribution coefficients were measured and modeled. •Distribution coefficients were lower in comparison to other reported values. •Organic carbon fraction times the K_OW yielded the best prediction model. •The incorporation of black carbon into a model did not improve the results. -- The organic carbon fraction times the octanol–water partition coefficient yielded the best prediction model for the sediment pore water distribution coefficient of PCBs

[en] This paper analyzed that vertical migration of Pb contents waters in Jiaozhou Bay, and revealed the influence of marine current on vertical migration process. Results showed that Pb contents in bottom waters of Jiaozhou Bay in April and July 1988 were 1.49-18.53 μg L^-1 and 12.68/-27.64 μg L^-1, respectively. The pollution level of Pb in bottom waters was moderate to heavy, and were showing temporal variations and spatial heterogeneity. The vertical migration process of Pb in April 1988 included a drifting process from the southwest to the north by means of the marine current was rapid in this region. The vertical migration process of Pb in July 1988 in the open waters included no drifting process since the flow rate of marine current was relative low in this region. The vertical migration process of Pb was jointly determined by vertical water’s effect, source input and water exchange, and the influence of marine current on the vertical migration of Pb in marine bay was significant. (paper)

[en] Weihe River Watershed above Linjiacun Section is taken as the research objective in this paper and COD is chosen as the water quality parameter. According to the discharge characteristics of point source pollutions and non-point source pollutions, a new method to estimate pollution loads-Characteristic Section Load Method(CSLM) is proposed and point source pollution and non-point source pollution loads of Weihe River Watershed above Linjiacun Section are calculated in the rainy, normal and dry season in the year 2007. The results show that the monthly point source pollution loads of Weihe River Watershed above Linjiacun Section are discharged stably, the monthly non-point source pollution loads of Weihe River Watershed above Linjiacun Section change greatly, the non-point source pollution load proportions of total pollution load of COD are gradually decreased in the rainy, normal and wet periods. (paper)

[en] The paper presents summarized data on the composition of surface wastewater from the territory of Samara. It also outlines the results of studies investigating main factors which affect surface wastewater composition and analyses the obtained tendencies. The research further defines a representative set of parameters, which gives an opportunity to diagnose the state of the system in general and to monitor surface run-off composition. The authors determine regressional dependences to assess a possible composition of surface run-off. This analysis is based on monitoring data and is supported by a representative set of parameters. In conclusion, the researchers provide results and their interpretation. (paper)