Herbicide Exposure and Toxicity to Aquatic Primary Producers

The aim of the present review was to give an overview of the current state of science concerning herbicide exposure and toxicity to aquatic primary producers. To this end we assessed the open literature, revealing the widespread presence of (mixtures of) herbicides, inevitably leading to the exposure of non-target primary producers. Yet, herbicide concentrations show strong temporal and spatial variations. Concerning herbicide toxicity, it was concluded that the most sensitive as well as the least sensitive species differed per herbicide and that the observed effect concentrations for some herbicides were rather independent from the exposure time. More extensive ecotoxicity testing is required, especially considering macrophytes and marine herbicide toxicity. Hence, it was concluded that the largest knowledge gap concerns the effects of sediment-associated herbicides on primary producers in the marine/estuarine environment. Generally, there is no actual risk of waterborne herbicides to aquatic primary producers. Still, median concentrations of atrazine and especially of diuron measured in China, the USA and Europe represented moderate risks for primary producers. Maximum concentrations due to misuse and accidents may even cause the exceedance of almost 60% of the effect concentrations plotted in SSDs. Using bioassays to determine the effect of contaminated water and sediment and to identify the herbicides of concern is a promising addition to chemical analysis, especially for the photosynthesis-inhibiting herbicides using photosynthesis as endpoint in the bioassays. This review concluded that to come to a reliable herbicide hazard and risk assessment, an extensive catch-up must be made concerning macrophytes, the marine environment and especially sediment as overlooked and understudied environmental compartments

In Situ Passive Sampling Techniques for Monitoring Environmental Mixture Exposure

A large number of passive sampler devices have been developed for in situ sensing of polar and nonpolar organic chemicals in the environment. This chapter compiles and analyzes available information on the current progress in quantitation theories and technological improvements. The results show that it is critical to determine sorbent phase-water partition coefficients and sampling rates of target analytes for quantitation with the equilibrium and kinetic sampling strategies. Compared to passive sampling of organic contaminants in air, overlying water and sediment porewater, which has been extensively documented, measurements of organic contaminants in soil and at the air-soil interface have been largely unsuccessful with passive samplers. In addition, the combination of in situ passive sampling devices and bioassays could be a promising tool for directly assessing air and water quality with biological effects