Modified whole effluent toxicity test to assess and decouple wastewater effects from environmental gradients.

Environmental gradients and wastewater discharges produce aggregated effects on marine populations, obscuring the detection of human impact. Classical assessment methods do not include environmental effects in toxicity tests designs, which could lead to incorrect conclusions. We proposed a modified Whole Effluent Toxicity test (mWET) that includes environmental gradients in addition to effluent dilutions, together with the application of Generalized Linear Mixed Models (GLMM) to assess and decouple those effects.

Effects of herbicides and freshwater discharge on water chemistry, toxicity and benthos in a Uruguayan sandy beach.

Environmental water chemistry analysis and microcosm toxicity bioassays (MTB) were performed to assess lethality of herbicides on the mole crab Emerita brasiliensis in a sandy beach affected by a freshwater discharge (Andreoni canal) from rice crops. A 5-yr macrocosm field sampling (MFS) was conducted to evaluate freshwater effects on population abundance. Propanil was only detected at the inner portion of the Andreoni canal (IAC), whereas quinclorac and clomazone were found at the IAC and at the canal mouth (CM).