Semifield testing of a bioremediation tool for atrazine‐contaminated soils: Evaluating the efficacy on soil and aquatic compartments

Abstract

The present study evaluated the bioremediation efficacy of a cleanup tool for atrazine-contaminated soils (Pseudomonas sp. ADP plus citrate [P. ADP + CIT]) at a semifield scale, combining chemical and ecotoxicological information. Three experiments representing worst-case scenarios of atrazine contamination for soil, surface water (due to runoff), and groundwater (due to leaching) were performed in laboratory simulators (100 × 40 × 20 cm). For each experiment, three treatments were set up: bioremediated, nonbioremediated, and a control. In the first, the soil was sprayed with 10 times the recommended dose (RD) for corn of Atrazerba and with P. ADP + CIT at day 0 and a similar amount of P. ADP at day 2. The nonbioremediated treatment consisted of soil spraying with 10 times the RD of Atrazerba (day 0). After 7 d of treatment, samples of soil (and eluates), runoff, and leachate were collected for ecotoxicological tests with plants (Avena sativa and Brassica napus) and microalgae (Pseudokirchneriella subcapitata) species. In the nonbioremediated soils, atrazine was very toxic to both plants, with more pronounced effects on plant growth than on seed emergence. The bioremediation tool annulled atrazine toxicity to A. sativa (86 and 100% efficacy, respectively, for seed emergence and plant growth). For B. napus, results point to incomplete bioremediation. For the microalgae, eluate and runoff samples from the nonbioremediated soils were extremely toxic; a slight toxicity was registered for leachates. After only 7 d, the ecotoxicological risk for the aquatic compartments seemed to be diminished with the application of P. ADP + CIT. In aqueous samples obtained from the bioremediated soils, the microalgal growth was similar to the control for runoff samples and slightly lower than control (by 11%) for eluates.

Evaluation of Arthrobacter aurescens Strain TC1 as Bioaugmentation Bacterium in Soils Contaminated with the Herbicidal Substance Terbuthylazine

“…aurescens TC1 was reported to biodegrade ATZ much more efficiently than most of the described s -triazine-degrading microorganisms (including the better-studied Pseudomonas sp. ADP [ 13 , 14 , 16 , 18 , 20 ]), and the same can be anticipated for TBA [ 20 , 21 ]. Triazine catabolism in A .…”

“…Such studies have involved mostly ATZ, and, as far as we are aware, only few focused on the biodegradation of the less bioavailable TBA in soil [ 15 , 18 ]. In particular, contrary to ATZ [ 13 , 14 , 16 , 17 ], the examination of both the bioremediation efficacy in soils and ability to minimize herbicide dispersion via the soil-water pathway at TBA concentrations relevant to spill situations in agricultural soils (e.g., 10× the recommended dose in crop growing, or higher [ 13 , 14 ]) is limited. The soil bacterium Arthrobacter aurescens strain TC1, isolated at a roadside herbicide spill site in the US, is able to use ATZ and many other chloro- s -triazine herbicides including TBA, as nitrogen and/or carbon sources [ 19 , 20 ].…”

Ethoprophos fate on soil–water interface and effects on non-target terrestrial and aquatic biota under Mediterranean crop-based scenarios

“…A stainless steel transportable soil flume system of 0.4 m 2 (from here onward referred to as soil-water simulator -SWS), with a controllable depth (maximum of 100 Â 40 Â 20 cm 3 ; length, width and height, respectively), with two articulated perforated platforms that can move independently allowing to work under different slopes was used (see Chelinho et al (2012) for additional details). This apparatus allows the collection of soil and water samples and the evaluation of the exposure and the effects on both terrestrial and aquatic compartments.…”

“…To address this knowledge gap, a semi-field crop-based experiment using a soil-water simulator was performed in the present study. This soil-water simulator was developed in a previous study (Chelinho et al, 2012), and its use under controlled conditions decreases variability in collected data which is often observed in field experiments, while maintaining the natural characteristics of the system under realistic field exposure conditions (e.g. soil type, slope, climatic condition, irrigation).…”

“…soil type, slope, climatic condition, irrigation). With this approach, the environmental risk of pesticide applications can be assessed for a particular agricultural area in an integrated way, taking into account not only the soil compartment but also specific soil-water transfer pathways such as leaching and runoff and soil elutriates as a measure of soil retention capacity, i.e., the potential of contaminants to be mobilized into aquatic systems through soil (Chelinho et al, 2012).…”