Background: Light-emitting diodes (LEDs) deliver higher levels of blue light to the retina than do conventional domestic light sources. Chronic exposure to high-intensity light (2,000–10,000 lux) has previously been found to result in light-induced retinal injury, but chronic exposure to relatively low-intensity (750 lux) light has not been previously assessed with LEDs in a rodent model.Objective: We examined LED-induced retinal neuronal cell damage in the Sprague-Dawley rat using functional, histological, and biochemical measurements.Methods: We used blue LEDs (460 nm) and full-spectrum white LEDs, coupled with matching compact fluorescent lights, for exposures. Pathological examinations included electroretinogram, hematoxylin and eosin (H&E) staining, immunohistochemistry (IHC), and transmission electron microscopy (TEM). We also measured free radical production in the retina to determine the oxidative stress level.Results: H&E staining and TEM revealed apoptosis and necrosis of photoreceptors, which indicated blue-light induced photochemical injury of the retina. Free radical production in the retina was increased in LED-exposed groups. IHC staining demonstrated that oxidative stress was associated with retinal injury. Although we found serious retinal light injury in LED groups, the compact fluorescent lamp (CFL) groups showed moderate to mild injury.Conclusion: Our results raise questions about adverse effects on the retina from chronic exposure to LED light compared with other light sources that have less blue light. Thus, we suggest a precautionary approach with regard to the use of blue-rich “white” LEDs for general lighting.Citation: Shang YM, Wang GS, Sliney D, Yang CH, Lee LL. 2014. White light–emitting diodes (LEDs) at domestic lighting levels and retinal injury in a rat model. Environ Health Perspect 122:269–276; http://dx.doi.org/10.1289/ehp.1307294

Even in trace amounts, estrogens such as 17beta-estradiol (E2), estrone (E1), estriol (E3), and 17alpha-ethinyl estradiol (EE2) may have adverse effects on humans and the aquatic ecosystem. Therefore, it is essential to be able to measure trace amounts of steroid estrogens in water. To date, most instruments are not sensitive enough to detect these chemicals in small samples of water. Sensitivity, however, may be improved by using appropriate derivatization reagents to modify the structures of these estrogens so that their ionization efficiency is increased, making them more detectable by liquid chromatography/mass spectrometry (LC/MS). This study uses dansyl chloride, 2-fluoro-1-methylpyridinium p-toluenesulfonate (FMPTS), and pentafluorobenzyl bromide (PFBBr) as derivatization reagents to react with the phenolic estrogens to make them more detectable in water. We also test how environmental matrices (wastewater effluent, river water, and drinking water) influence the detectability of these estrogens. Both qualitative and semi-quantitative comparisons of these derivatization methods were made. We found that dansyl chloride derivatives created signal intensities one or two orders of magnitude greater than those normally found in underivatized estrogen standards. The signals derived by FMPTS were analyte-dependent, and the products derived from E1, E2, and EE2 produced 2.19 to 12.1 times the signal intensity of underivatized E1, E2, and EE2. The product derived from E3 produced weaker signals than that produced by underivatized E3. The PFBBr derivatives produced signals that were as much as 5.8 times those found in the underivatized estrogens. When these derivatization methods were applied to river water, drinking water and effluents from a sewage treatment plant (STP), the different matrices were found to significantly suppress the signals if we used electrospray ionization, though this influence became less significant if we used atmospheric pressure chemical ionization. This study suggests that PFBBr derivatization can best be used for the detection of these estrogens in complex environmental matrices such as river water and STP effluents and that the dansyl chloride derivatization is best used for clean samples such as drinking water.

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