Bioretention Cells Provide a 10-Fold Reduction in 6PPD-Quinone Mass Loadings to Receiving Waters: Evidence from a Field Experiment and Modeling

Road runoff to streams and rivers exposes aquatic organisms to complex mixtures of chemical contaminants. In particular, the tire-derived chemical 6PPD-quinone (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine-quinone) is acutely toxic to several species of salmonids, which are critical to fisheries, ecosystems, and Indigenous cultures. We therefore urgently require interventions that can reduce loadings of 6PPD-quinone to salmonid habitats. Herein, we conducted a spike and recovery experiment on a full-scale, mature bioretention cell to assess the efficacy of stormwater green infrastructure technologies in reducing 6PPD-quinone loadings to receiving waters. We then interpreted and extended the results of our experiment using an improved version of the "Bioretention Blues" contaminant transport and fate model. Overall, our results showed that stormwater bioretention systems can effectively mitigate >∼90% of 6PPD-quinone loadings to streams under most "typical" storm conditions (i.e., < 2-year return period). We therefore recommend that stormwater managers and other environmental stewards redirect stormwater away from receiving waters and into engineered green infrastructure systems such as bioretention cells.

Clinical and pathological features of membranous glomerulonephritis of systemic lupus erythematosus

The prognostic significance of glomerular inflammation in patients with lupus membranous glomerulonephritis (MGN) was evaluated by classifying 100 renal biopsies from lupus patients according to World Health Organization (WHO) criteria and correlating the histology with clinical data. There were 22 cases of MGN: in 3 the lesion was pure MGN (Va); in the remainder, diffuse MGN was modified by superimposed mesangial proliferation in 6 (Vb), segmental glomerulonephritis (GN) or sclerosis in 10 (Vc), and diffuse GN in 3 (Vd). Patients in the four categories had similar clinical presentations. When the 4 patients with active proliferative glomerulonephritis (PGN) were grouped and compared to those without PGN, they had more active serologies. Quantitation of glomerular electrondense deposits in MGN showed variation in the percentage of basal lamina covered by subepithelial deposits, segmental subepithelial deposits in 4 cases, focal segmental subendothelial deposits in most cases and massive subendothelial deposits in 5 biopsies. 4 of the latter patients had active PGN, suggesting that only extensive subendothelial deposits are pathogenetically significant. The predicted 5-year survival for all MGN patients was 90%, and the only 2 deaths were not related to renal failure. Thus, it appears valid to include mixed lesions in the membranous category, but it is our impression that the immediate course and prognosis of SLE and associated PGN depends upon the extent and reversibility of the inflammatory lesions.