Pharmaceuticals have special attention of researchers over the world due to their possible effect on the environment and humans. This paper focuses on the photolysis of nitrofurantoin in different water matrices. Nitrofurantoin photodegradation has been indicated as a pseudo-first order photoreaction. The indirect photodegradation rate of nitrofurantoin (river water, k₁ = 0.0088 min⁻¹ and synthetic wastewater, k₁ = 0.0154 min⁻¹) was slower than its direct photolysis rate (ultrapure water, k₁ = 0.0176 min⁻¹). The highest value of quantum yield of nitrofurantoin photodegradation (ϕ = 0.2047) was observed at pH = 4, while at higher pH-values it decreased. Furthermore, the mechanism of nitrofurantoin photodegradation is proposed. Heterocyclic ring opening and further hydrolysis, nucleophilic aromatic photosubstitution and homolytic N–N bond cleavage are suggested as three main initial processes of nitrofurantoin photodegradation. Acute toxicity study of nitrofurantoin and its photoproducts with regard to luminescence inhibition of Vibrio fischeri showed that the toxic effect of nitrofurantoin (EC₅₀ = 4.0 mg L⁻¹) decreases by photolysis.

中文翻译：

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环境因素对水中呋喃妥因光解作用的影响及急性毒性评价

药物因其可能对环境和人类产生影响而受到全世界研究人员的特别关注。本文重点研究呋喃妥因在不同水基质中的光解。呋喃妥因光降解已被表明为伪一级光反应。呋喃妥因的间接光降解速率（河水，k ₁ = 0.0088 min ^-1和合成废水，k ₁ = 0.0154 min ^-1）比其直接光解速率（超纯水，k ₁ = 0.0176 min ^-1）慢。呋喃妥因光降解量子产率最高值 ( ϕ= 0.2047) 在 pH = 4 时观察到，而在较高的 pH 值下它会降低。此外，还提出了呋喃妥因光降解的机理。杂环开环和进一步水解、亲核芳香光取代和均裂 N-N 键断裂被认为是呋喃妥因光降解的三个主要初始过程。呋喃妥因及其光产物对费氏弧菌发光抑制的急性毒性研究表明，呋喃妥因 (EC ₅₀ = 4.0 mg L ^-1 )的毒性作用通过光解作用降低。