Arata Harada

Nationwide monitoring of selected antibiotics: Distribution and sources of sulfonamides, trimethoprim, and macrolides in Japanese rivers.

We report the results of a nationwide survey of commonly used human and veterinary antibiotics (7 sulfonamides, trimethoprim, and 4 macrolides) in 37 Japanese rivers. Concentrations of the sum of the 12 target antibiotics ranged from undetectable to 626 ng/L, with a median of 7.3 ng/L for the 37 rivers. Antibiotics concentrations were higher in urban rivers than in rural rivers and were correlated with those of molecular markers of sewage (crotamiton and carbamazepine). Macrolides were dominant over sulfonamides in urban rivers. Sulfonamides, especially sulfamethazine (used in animals), were dominant in a few rivers in whose catchment animal husbandry is active. However, these signals of veterinary antibiotics were overwhelmed by those of human antibiotics in lower reaches of most rivers. The analysis of the antibiotics in all 88 samples showed that the target antibiotics in Japanese rivers are derived mainly from urban sewage, even though larger amounts of antibiotics are used in livestock. Most of the livestock waste-derived antibiotics are unlikely to be readily discharged to surface waters.

Multiple evaluations of the removal of pollutants in road runoff by soil infiltration.

Groundwater replenishment by infiltration of road runoff is expected to be a promising option for ensuring a sustainable urban water cycle. In this study, we performed a soil infiltration column test using artificial road runoff equivalent to approximately 11-12 years of rainfall to evaluate the removal of pollutants by using various chemical analyses and bioassay tests. These results indicated that soil infiltration treatment works effectively to remove most of the pollutants such as organic matter (chemical oxygen demand (CODMn) and dissolved organic carbon (DOC)), P species, polycyclic aromatic hydrocarbons (PAHs), numerous heavy metals and oestrogenic activities. Bioassay tests, including algal growth inhibition test, Microtox and mutagen formation potential (MFP) test, also revealed effective removal of toxicities by the soils. However, limited amounts of NO3, Mn, Ni, alkaline earth metals, perfluorooctane sulphonate (PFOS) and perfluorooctane sulphonamide (FOSA) were removed by the soils and they possibly reach the groundwater and cause contamination.

Biological effects of PPCPs on aquatic lives and evaluation of river waters affected by different wastewater treatment levels.

The existence of pharmaceuticals and personal care products (PPCPs) in the water environment is an emerging problem. In this study, we investigated the toxicity of eleven PPCPs through bioassays on bacteria, algae, crustaceans, amphibians and protozoa, and compared the toxicology indexes with the concentration of PPCPs in river water for ecotoxiclogical risk evaluation. Toxicity of the eleven PPCPs was observed and the values of EC50 or LC50 were in the order of mg/L. A distinctive finding is that antibacterial triclosan affected all aquatic lives tested. The effects of PPCPs varied according to species of lives. Contamination from PPCPs was detected at observation stations on the river, and the range of concentration was in the order of ng/L far lower than the values of toxicity indexes EC50 or LC50. Ecotoxicological risks posed by PPCPs at the observation stations was evaluated using the concentration in the river water and the NOEC examined by AGI tests. The results revealed that three PPCPs, triclosan, clarithromycin, and azithromycin, posed an ecotoxiclogical risk in rivers where wastewater treatment systems are not yet well developed.