{'fraction_non_alphanumeric': 0.042328042328042326, 'fraction_numerical': 0.05238095238095238, 'mean_word_length': 4.782874617737003, 'pattern_counts': {'":': 0, '<': 1, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Effects of carbon amendment on in situ atrazine degradation and total microbial biomass

This study elucidates the effects of carbon amendment on metabolic degradation of atrazine (6-chloro-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine) and total microbial biomass in soil. Degradation of 14C-ring-labelled atrazine was monitored in laboratory incubations of soils supplemented with 0, 10, 100 and 1000 μg g−1 sucrose concentrations. An experiment to determine the effect of carbon amendment on total microbial biomass and soil respiration was carried out with different concentrations of sucrose and non-labelled atrazine. The soils were incubated at a constant temperature and constant soil moisture at water potential of −15 kPa and a soil density of 1.3 g cm−3. Mineralization of 14C-ring-labelled atrazine was monitored continuously over a period of 59 d in the first experiment. The CO2 production was monitored for 62 d in the second experiment and microbial biomass determined at the end of the incubation period. The addition of 1000 μg g−1 sucrose reduced atrazine mineralization to 43.5% compared to 51.7% of the applied amount for the treatment without sucrose. The addition of 1000 μg g−1 sucrose modified the transformation products to 1.08 μg g−1 deisopropylatrazine (DIA), 0.32 μg g−1 desethylatrazine (DEA) and 0.18 μg g−1 deisopropyl-2-hydroxyatrazine (OH-DIA). Treatment without sucrose resulted in formation of 0.64 μg g−1 hydroxyatrazine (HA), 0.28 μg g−1 DIA and 0.20 μg g−1 OH-DIA. Atrazine dealkylation was enhanced in treatments with 100 and 1000 μg g−1 of sucrose added. HA metabolite was formed in the control (no sucrose) and in the presence of 10 μg g−1 of sucrose, whereas DEA was only detected in treatment with 1000 μg g−1 sucrose. Results indicate that total microbial biomass increased significantly (P < 0.001) with the addition of 1000 μg g−1 sucrose.