Aquatic chemistry is becoming both a rewarding and substantial area of inquiry and is drawing many prominent scientists to its fold. Its literature has changed from a compilation of compositional tables to studies of the chemical reactions occurring within the aquatic environments. But more than this is the recognition that human society in part is determining the nature of aquatic systems. Since rivers deliver to the world ocean most of its dissolved and particulate components, the interactions of these two sets of waters determine the vitality of our coastal waters. This significant vol ume provides not only an introduction to the dynamics of aquatic chem istries but also identifies those materials that jeopardize the resources of both the marine and fluvial domains. Its very title provides its emphasis but clearly not its breadth in considering natural processes. The book will be of great value to those environmental scientists who are dedicated to keeping the resources of the hydrosphere renewable. As the size of the world population becomes larger in the near future and as the uses of materials and energy show parallel increases, the rivers and oceans must be considered as a resource to accept some of the wastes of society. The ability of these waters and the sediments below them to accommodate wastes must be assessed continually. The key questions relate to the capacities of aqueous systems to carry one or more pollutants."

Metal pollution in the aquatic environment

N2O is an important greenhouse gas and the primary stratospheric ozone depleting substance. Its deleterious effects on the environment have prompted appeals to regulate emissions from agriculture, which represents the primary anthropogenic source in the global N2O budget. Successful implementation of mitigation strategies requires robust bottom-up inventories that are based on emission factors (EFs), simulation models, or a combination of the two. Top-down emission estimates, based on tall-tower and aircraft observations, indicate that bottom-up inventories severely underestimate regional and continental scale N2O emissions, implying that EFs may be biased low. Here, we measured N2O emissions from streams within the US Corn Belt using a chamber-based approach and analyzed the data as a function of Strahler stream order (S). N2O fluxes from headwater streams often exceeded 29 nmol N2O-N m−2⋅s−1 and decreased exponentially as a function of S. This relation was used to scale up riverine emissions and to assess the differences between bottom-up and top-down emission inventories at the local to regional scale. We found that the Intergovernmental Panel on Climate Change (IPCC) indirect EF for rivers (EF5r) is underestimated up to ninefold in southern Minnesota, which translates to a total tier 1 agricultural underestimation of N2O emissions by 40%. We show that accounting for zero-order streams as potential N2O hotspots can more than double the agricultural budget. Applying the same analysis to the US Corn Belt demonstrates that the IPCC EF5r underestimation explains the large differences observed between top-down and bottom-up emission estimates.

https://www.pnas.org/content/pnas/112/32/9839.full.pdf

Indirect nitrous oxide emissions from streams within the US Corn Belt scale with stream order

The highway as a source of water pollution: An appraisal with the heavy metal lead.

Nitrous oxide emissions from streams within the US Corn Belt scale with stream order

Problem statement: The objective of this research was to evaluate the degree of heavy metal contamination in lakes and the extent to whic h the sediment quality of the lakes of Bangalore city has deteriorated. Approach: In this study, heavy metals such as Cd, Co, Cu, Cr , Mn, Pb, Ni and Zn in lake bed sediments were analyzed using comparative sediment quality guidelines from various derived criteria. The selection of sampling points was based upon inflow and outflow regions of the lakes; geographical proximity of industrial units i n relation to their effluent discharges; proximity of residential sites located on the banks of the wetla nd systems; drainage patterns and accessibility towards the lakes. Digestion and analysis of the sa mples were done by microwave-assisted digestion and atomic absorption spectrophotometry respectivel y. Results: The extent of sediment quality deterioration was more pronounced in Cu (203.50 ppm) and Ni (97.64 ppm) followed by Pb (206.0 ppm) and Cd (8.38 ppm). Cr (96.70 ppm) failed a single sediment quality guideline while Zn (220.0 ppm), Mn (176.0 ppm) and Co (47.7 ppm) remained within the safety levels of sediment quality guidelines prescribed for the study. The Sediment G eo-accumulation Index showed that Co, Cu and Pb showed moderate levels of pollution while the Pollu tion Load Index (PLI) between heavy metals in the lakes produced the following outputs: Ni > Pb > Cd > Cu > Cr > Co > Zn > Mn. Conclusion: This study proves that the level of sustained metal cont amination of the fragile urban wetlands has not receded even after the recent urban wetlands rejuve nation works were completed. This prolonged presence in excessive levels of the studied heavy m etals in the bed sediments casts doubt on the choic e and effectiveness of the any mitigation measures in the long run.

Heavy Metals Analysis and Sediment Quality Values in Urban Lakes

Nine trace elements of biological concern: Cr, Co, Cu, Cd, Ni, Pb, Hg, Zn and Ag were investigated in the sediments of the most important coastal steams in Israel. All of these are subjected to some degree of domestic and/or industrial sewage input with the consequent liability of contamination by trace metals. The Ayyalon, Gadura, Qishon and locally the Hadera rivers contain sediments exhibiting severe pollution effects. There is a danger of infiltration through the soils into the groundwaters as well as exposing nearshore fauna to sediments contaminated by possibly toxic trace metals. The other rivers bear smaller levels of trace metals; however, an increase of the Pb and the Zn levels occurs near major highways.

J. Navrot

Papers

Aspects of trace metal contamination in the coastal rivers of Israel