Environmental context. Ammonia emissions from inorganic nitrogen fertilisers used in agriculture can impact air quality, human health and ecology. This study quantifies such emissions and their controlling factors from UK and Ireland agricultural soils. Emissions are variable and, from non-urea fertilisers, substantially exceed maximum emission factors used by the UK Department for Environment, Food and Rural Affairs. This suggests that UK emission factors need to be refined further, with consideration of inter alia land-use, fertiliser type, soil pH and chemical inhibitors.

This article belongs to the collection Dedication to Prof. Edward Tipping.

Environmental context. 

Rare earth elements (REEs) are technologically critical elements released into the environment by various anthropogenic activities, and whose ecotoxicological impacts are still largely unknown. REE binding to natural organic matter (NOM) is key to understand their fate and bioavailability in the environment. With this work, it is now possible to predict REE binding to NOM in various environments using various speciation software (ECOSAT, ORCHESTRA, Visual MINTEQ).

This article belongs to the collection Dedication to Prof. Edward Tipping.

Environmental context. Natural dissolved organic matter strongly influences the biogeochemistry and bioavailability of trace metals in natural waters. Chemical equilibrium models are often used to predict the relative importance of the free metal cation, a recognised indicator of the metal’s bioavailability. Here we show how the nature of the organic matter varies between two lakes, affecting the measured speciation of copper and nickel, a result that challenges existing chemical equilibrium models.

This article belongs to the collection Dedication to Prof. Edward Tipping.