Spatial and temporal variation of algal assemblages in six Midwest agricultural streams having varying levels of atrazine and other physicochemical attributes

Determining in situ periphyton community responses to nutrient and atrazine gradients via pigment analysis

“…Antagonistic effects would dampen the response whereas synergistic or additive effects would enhance the response but make separating individual effects difficult. For example, variance partitioning determined that atrazine had few effects on Midwest (U.S.) agricultural streams but that significant ambiguity existed in determining effects of specific variables on periphyton communities due to the variation shared between groups of variables (Andrus et al, 2015). In the South Nation River watershed, NO 3 − and atrazine were highly correlated because of their widespread use on corn crops, a major annual crop in this watershed.…”

Pharmaceuticals and pesticides archived on polar passive sampling devices can be stable for up to 6 years

“…Pharmaceuticals and pesticides are contaminants frequently measured in waters using passive sampling devices [1][2][3]. Contaminant inputs can be highly stochastic (e.g., driven by runoff events), necessitating intensive monitoring efforts [4,5]. Thus, the handling of large numbers of samples in the laboratory over a given field sampling season is quite common, making the storage of field-deployed passive sampling devices a convenient and necessary element of water quality monitoring.…”

Effects of atrazine on egg masses of the yellow-spotted salamander (Ambystoma maculatum) and its endosymbiotic alga (Oophila amblystomatis)

“…However, in the aquatic environment, even under conditions of inadvertent direct overspray, it is considered extremely unlikely that an intact formulation would reach the nontarget receptor due to markedly differing physiochemical properties and characteristics, (e.g. solubility, soil-water partitioning coefficients, stability and volatility) (Andrus et al, 2013(Andrus et al, , 2015Van Der Kraak et al, 2014). Moreover, the primary source of atrazine contamination in surface water resources is via runoff, and the low likelihood of a formulation migrating intact in the runoff fraction renders exposure to the formulation even less likely in the aquatic environment.…”

“…Considering the low likelihood of atrazine and its formulated adjuvants co-occurring in aquatic systems due to markedly different individual physiochemical properties (e.g., solubility, partitioning coefficients, stability, volatility etc.) (Andrus et al, 2013(Andrus et al, , 2015van der Kraak et al, 2014), results of toxicity testing with the AI alone are an important component in understanding risk in the environment, and particularly the aquatic environment. As a result, we aimed to confirm this range of sensitivity with whole egg masses using technicalgrade atrazine and a robust study design (see Harris et al, 2014).…”