2263 Environmental Toxicology and Chemistry, Vol. 25, No. 9, pp. 2263–2271, 2006  2006 SETAC Printed in the USA 0730-7268/06 $12.00 + .00 Field-Based Effects Measures IN SITU ON-LINE TOXICITY BIOMONITORING IN WATER: RECENT DEVELOPMENTS ALMUT GERHARDT,*† MARY KATE INGRAM,‡ IK JOON KANG,§ and SHIMON ULITZUR †LimCo International, An der Aa 5, 49477 Ibbenbueren, Germany ‡Lakehead University, Biology Department, 955 Oliver Road, Thunder Bay, Ontario P7A 4K2, Canada §Seiko Electric, Toko 2 chome, Hakata-ku, Fukuoka 812-0008, Japan CheckLight, P.O. Box 72, Qiryat-Tiv’on 36000, Israel ( Received 18 August 2005; Accepted 27 February 2006) Abstract—In situ on-line biomonitoring is an emerging branch of aquatic biomonitoring. On-line biomonitoring systems use behavioral and/or physiological stress responses of caged test organisms exposed in situ either in a bypass system or directly in- stream. Sudden pollution waves are detected by several existing single-species on-line biomonitors, which until now have been placed mostly in streamside laboratories. However, recent achievements have been multispecies biomonitors, mobile biomonitors for direct in-stream use, development of new instruments, new methods for data analysis and alarm generation, biomonitors for use in soil and sediment, and scientific research supporting responses as seen in on-line biomonitors by linking them to other biological and ecological effects. Mobile on-line monitoring platforms containing an array of biomonitors, biosensors, and chemical monitoring equipment might be the future trend, especially in monitoring transboundary rivers at country borders as well as in coastal zones. Keywords—In situ tests On-line biomonitors Biological early warning systems Toxicity monitoring INTRODUCTION Biomonitoring is a truly interdisciplinary applied science based on both ecology and ecotoxicology [1]. Two types of biomonitoring methods that integrate these disciplines exist; trend biomonitoring (using ecological methods and community structure; e.g., diversity indices, similarity indices, species richness, and percentage of Ephemeroptera, Plecoptera, and Trichoptera taxa), and community function (e.g., Functional Feeding Groups) and rapid bioassessment methods (e.g., sap- roby index, biotic indices, and Biological Monitoring Working Party index). However, other indicator methods might be added depending on the purpose of biomonitoring, such as fish health status, macrophytes, or algae; the latter two methods are in- valuable for eutrophication monitoring. All these methods are, unfortunately, not based on ecotoxicology, and because pol- lution is more often caused by chemical contaminant mixtures than by oxygen depletion, we need to improve current eco- toxicological methods for pollution monitoring. Several ap- plicable methods include in situ on-line biomonitoring with so-called biological early warning systems (BEWS) below tox- ic effluents or along large rivers, especially at national borders, to detect toxicity spikes and to provide data regarding potential permit violations. Moreover, rapid toxicity tests can be applied directly in situ based on behavioral measurements (e.g., avoid- ance responses) or on survival, growth, genomics, or other metrics. In situ cage exposures are another appropriate method for long-term exposures. [1]. The development of on-line and off-line in situ biotests for toxicological assessment and biomonitoring of water quality follows the United Nations Agenda 21 (http://www.un.org), which highlights the protection and sustainable management of water as a restricted resource. Biomonitoring, especially on- * To whom correspondence may be addressed (almutg@web.de). Presented at the 4th SETAC World Congress, Portland, OR, USA, November 14–18, 2004. line toxicity biomonitoring, is an emerging field that is playing an increasing role in the surveillance of environmental quality, often as a complement to chemical monitoring [1–3], and should be integrated in the European Water Framework Di- rective. On-line biomonitors frequently use behavior as an endpoint, which provides a visual and, thus, measurable response at the whole-organism level. This method generates fast and sensitive results that can be integrated into many biological functions [4]. The key is to employ invertebrates or younger life stages that tend to be more sensitive to toxicants and respond more rapidly than adult stages or vertebrates, but with the proviso that the effects are nonlethal. The basic idea of an automated biological sensor for water- quality management was first proposed by Cairns et al. [5]. Automated biomonitors operate on a real-time basis using liv- ing organisms as sensors, ideally providing a continuous flow of information regarding water quality. On-line biomonitors, continuous (dynamic) biotests, automated biotests, or BEWS are characterized by three components: a test organism, an automated detection system, and an alarm system. The tasks of on-line biomonitors are to detect pollution waves by re- cording the ‘‘integrated biological response’’ of the test or- ganism to pollution spikes [3]. BACKGROUND In 1986, a Sandoz chemical storage building in Basel (Swit- zerland) caught fire, spewing approximately 40 tons of insec- ticides and 400 kg of atrazine into the Rhine River, resulting in the devastation of a large portion of the river’s biocoenosis as well as drinking-water production (40 waterworks had to close for one month) from an already polluted river [6]. Shortly after the accident, an automated biomonitoring system, such as the dynamic Daphnia test (a device that electronically mea- sures Daphnia swimming behavior) [7], located 500 km down-