Henrik Kylin

Formation of disinfection by-products (DBPs) in drinking water production constitutes a health hazard. The total amount of DBPs is usually measured as adsorbable organic halogens (AOX). We determined AOX in samples from four full-scale drinking water treatment plants (DWTPs) in Sweden using different types of raw waters and treatments. Raw water, water before and after chlorination or chloramination and tap water were sampled on five occasions during one year without applying quencher to stop chlorination reactions. Coagulation removed most (> 95%) of the AOX present in the raw water at one DWTP. Sand filtration used in all DWTPs had no clear effect on AOX levels already present in the intake water, while some AOX formation occurred during Ultraviolet (UV) treatment. AOX increased dramatically at all DWTPs during both chlorination and chloramination due to the formation of DBPs. When not using any quencher similar AOX formation was found in both chlorine and chloramine treated water, showing that substantial DBP formation occurred upon chloramination even if few regulated DBPs were detected in these DWTPs in previous assessments. Because the contribution of non-DBP AOX varies between sources and treatment processes, ∆AOX, i.e., AOX in final water subtracted by AOX prior to chemical disinfection, should be considered in DBP assessments.

An undescribed breaching behaviour of a beaked whale Mesoplodon sp. was seen west of Brazil in the deep waters off the Abrolhos Bank. Consecutive breaches were performed in a counterclockwise circle, the whale always falling on its left side with its head inwards where two other whales were basking.

Improved characterization of dissolved organic matter (DOM) in source waters used for drinking water treatment is necessary to optimize treatment processes and obtain high drinking water quality.

The formation of disinfection by-products (DBPs) during drinking water treatment has been associated with various health concerns but the agents, i.e., the DBPs that cause these health concerns, are still unknown.

In August 2005, marine debris was counted on two Arctic beaches in the Russian Far East. On the north coast of the Chukchi Peninsula east of Kolyuchin Bay, a beach stretch of ca. 2.4 km held a total of 736 items, 0.024 items m‑2, while no more than 0.0011 items m‑2, 12 items in total, were found on a beach stretch of ca. 1.2 km on southern Wrangel Island. The likely explanation for this difference is that the area around the mainland beach is ice-free for a longer period each year, but a contributing factor may be that late spring ice movement removed plastic from the beach on Wrangel Island. The language on the few items with identifiable labels was for the most part Russian or English, making the Chukchi Sea a possible source region. Beaches at the same latitude in the Atlantic may hold more debris on account of the higher human population density, more shipping and transport of floating debris unhindered by a narrow strait that is ice-covered much of the year. Fishing gear blown across the tundra is suggested as a potential threat to reindeer and other terrestrial wildlife.

Disinfection by-products (DBPs) are potentially toxic compounds formed upon chemical disinfection of drinking water. Controlling the levels and characteristics of dissolved organic matter (DOM) as precursor material for DBPs is a major target to reduce DBP formation. A pilot-scale treatment including suspended ion exchange (SIX®), a ceramic microfilter (CeraMac®) with in-line coagulation and optional pre-ozonation followed by granular activated carbon (GAC) filtration was compared with a conventional full-scale treatment based on DOM removal and DBP formation using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), rapid fractionation, liquid chromatography organic carbon detection (LC-OCD), adsorbable organic halogens (AOX) and trihalomethane (THM) analysis. The new treatment combination showed different selectivity for DOM removal, compared to the conventional, leading to changes in composition of the DBPs formed. SIX® and GAC had the largest impacts on reducing AOX and THM formation potentials but the high adsorptive capacity of GAC affected the diversity of detected DBPs most. Chlorination and chloramination of pilot treated water with doses normally used in Sweden produced low levels of AOX compared to the full-scale treatment, but FT-ICR MS revealed an abundance of brominated DBP species in contrast with the conventional treatment, which were dominated by chlorinated DBPs. This finding was largely linked to the high DOM removal by the pilot treatment, causing an increased Br⁻/C ratio and a higher formation of HOBr. Potential increases in Br-DBPs are important to consider in minimizing health risks associated with DBPs, because of the supposed higher toxicity of Br-DBPs compared to Cl-DBPs.