Lake Kumphawapi revisited – The complex climatic and environmental record of a tropical wetland in NE Thailand

Kumphawapi, which is Thailand’s largest natural freshwater lake, contains a >10,000-year-long climatic and environmental archive. New data sets (stratigraphy, chronology, hydrogen isotopes, plant macrofossil and charcoal records) for two sedimentary sequences are here combined with earlier multi-proxy studies to provide a comprehensive reconstruction of past climatic and environmental changes for Northeast Thailand. Gradually higher moisture availability due to a strengthening of the summer monsoon led to the formation of a large shallow lake in the Kumphawapi basin between >10,700 and c. 7000 cal. BP. The marked increase in moisture availability and lower evaporation between c. 7000 and 6400 cal. BP favoured the growth and expansion of vegetation in and around the shallow lake. The increase in biomass led to gradual overgrowing and infilling, to an apparent lake level lowering and to the development of a wetland. Multiple hiatuses are apparent in all investigated sequences between c. 6500 and 1400 cal. BP and are explained by periodic desiccation events of the wetland and erosion due to the subsequent lake level rise. The rise in lake level, which started c. 2000 cal. BP and reached shallower parts c. 1400 cal. BP, is attributed to an increase in effective moisture availability. The timing of hydroclimatic conditions during the past 2000 years cannot be resolved because of chronological limitations.

Urinary thrombomodulin levels were significantly higher following occupational exposure to chemicals, in the presence of dipstick protein, but not in the presence of dipstick blood

Currently, there are no biomarkers which can identify patients with an increased risk of developing urothelial cancer as a result of occupational chemical exposure. The aim of this study was to evaluate the relationships between final diagnosis and 22 biomarkers measured in urine, serum and plasma collected from 156 hematuric patients. Fourteen of the 80 patients (17.5%) with urothelial cancer and 13/76 (17.1%) of the controls were deemed to have a history of chemical exposure. We applied Fisher's exact tests to explore associations between chemical exposure and final diagnosis, and tumor stage and grade, where applicable; ANOVA and t-test to compare age across patients with and without chemical exposure; and Zelen's exact test to evaluate relationships across final diagnosis, chemical exposure and smoking. Following pre-selection of biomarkers using Lasso, we identified biomarkers with differential levels across patients with and without chemical exposure using Welch's t-test. Using a one-sided t-test and considering multiple testing using FDR, we observed that TM levels in urine were significantly higher in samples from patients with a history of chemical exposure regardless of their diagnosis as control or urothelial cancer (one-sided t-test, p_UC = 0.014 and p_CTL = 0.043); in the presence of dipstick protein and when urinary pH levels ≤ 6 (p = 0.003), but not in the presence of dipstick blood (p = 0.115). Urothelial cancer patients with a history of chemical exposure were significantly younger (64.1 years) than those without chemical exposure (70.2 years) (one-sided t-test p-value = 0.012); and their tumors were higher grade (Fisher's exact test; p = 0.008). There was a strong association between a history of chemical exposure and smoking in urothelial cancer patients (Zelen's exact test; p = 0.025). Elevated urinary thrombomodulin levels could have the potential to identify chemical exposure in hematuric patients at high risk of developing urothelial cancer.