Field-Based Effects Measures in SITU ON-LINE TOXICITY BIOMONITORING in WATER: RECENT DEVELOPMENTS

Environmental Toxicology and Chemistry, Vol. 25, No. 9, pp. 2263–2271, 2006 ᭧ 2006 SETAC Printed in the USA 0730-7268/06 $12.00 ϩ .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 line toxicity biomonitoring, is an emerging field that is playing Biomonitoring is a truly interdisciplinary applied science an increasing role in the surveillance of environmental quality, based on both ecology and ecotoxicology [1]. Two types of often as a complement to chemical monitoring [1–3], and biomonitoring methods that integrate these disciplines exist; should be integrated in the European Water Framework Di- trend biomonitoring (using ecological methods and community rective. structure; e.g., diversity indices, similarity indices, species On-line biomonitors frequently use behavior as an endpoint, richness, and percentage of Ephemeroptera, Plecoptera, and which provides a visual and, thus, measurable response at the Trichoptera taxa), and community function (e.g., Functional whole-organism level. This method generates fast and sensitive Feeding Groups) and rapid bioassessment methods (e.g., sap- results that can be integrated into many biological functions roby index, biotic indices, and Biological Monitoring Working [4]. The key is to employ invertebrates or younger life stages Party index). However, other indicator methods might be added that tend to be more sensitive to toxicants and respond more depending on the purpose of biomonitoring, such as fish health rapidly than adult stages or vertebrates, but with the proviso status, macrophytes, or algae; the latter two methods are in- that the effects are nonlethal. valuable for eutrophication monitoring. All these methods are, The basic idea of an automated biological sensor for water- unfortunately, not based on ecotoxicology, and because pol- quality management was first proposed by Cairns et al. [5]. lution is more often caused by chemical contaminant mixtures Automated biomonitors operate on a real-time basis using liv- than by oxygen depletion, we need to improve current eco- ing organisms as sensors, ideally providing a continuous flow toxicological methods for pollution monitoring. Several ap- of information regarding water quality. On-line biomonitors, plicable methods include in situ on-line biomonitoring with continuous (dynamic) biotests, automated biotests, or BEWS so-called biological early warning systems (BEWS) below tox- are characterized by three components: a test organism, an ic effluents or along large rivers, especially at national borders, automated detection system, and an alarm system. The tasks to detect toxicity spikes and to provide data regarding potential of on-line biomonitors are to detect pollution waves by re- permit violations. Moreover, rapid toxicity tests can be applied cording the ‘‘integrated biological response’’ of the test or- directly in situ based on behavioral measurements (e.g., avoid- ganism to pollution spikes [3]. ance responses) or on survival, growth, genomics, or other metrics. In situ cage exposures are another appropriate method BACKGROUND for long-term exposures. [1]. In 1986, a Sandoz chemical storage building in Basel (Swit- The development of on-line and off-line in situ biotests for zerland) caught fire, spewing approximately 40 tons of insec- toxicological assessment and biomonitoring of water quality ticides and 400 kg of atrazine into the Rhine River, resulting follows the United Nations Agenda 21 (http://www.un.org), in the devastation of a large portion of the river’s biocoenosis which highlights the protection and sustainable management as well as drinking-water production (40 waterworks had to of water as a restricted resource. Biomonitoring, especially on- close for one month) from an already polluted river [6]. Shortly * To whom correspondence may be addressed ([email protected]). after the accident, an automated biomonitoring system, such Presented at the 4th SETAC World Congress, Portland, OR, USA, as the dynamic Daphnia test (a device that electronically mea- November 14–18, 2004. sures Daphnia swimming behavior) [7], located 500 km down- 2263 2264 Environ. Toxicol. Chem. 25, 2006 A. Gerhardt et al. stream detected and reported the event. Samples taken at the of technical errors [3]. The movement of one healthy water time of the alarm showed that the same types of pesticides flea up and down through many light beams, with the re- triggering these alarms were stored in the Sandoz facility. As maining dead water fleas resting on the bottom of the exposure a result of the speed and accuracy of this single monitoring vessel, produced data similar to those of numerous healthy station detection, many European governments mandated ad- water fleas passing through fewer light beams. Video tracking ditional monitoring stations along the river. The BEWS grew has rectified this error by monitoring each individual water into a new paradigm of environmental monitoring, especially flea; however, cross-over swimming is still a problem. Water in large European rivers at country borders. flea tests often use prefiltered test water, which eliminates par- The desired parameters of preformed biomonitors include ticle-bound toxicants. The European Water Framework Direc- full automation, real-time detection and data generation, sen- tive recommends using unfiltered water for testing purposes. sitivity to pollution, rapid response, easy operation, reliable Biomonitors that pretreat the water through filtration will not alarm interpretation, minimal false alarms, and minimal costs, be able to fulfill this demand. The water fleas need to be fed maintenance efforts, and training requirements. The organisms continuously by a stable algae culture, which might represent chosen range from vertebrates (fish) to arthropods (insects, another uncertainty. crustaceans, and daphnids) via oligochaetes to microbes (algae Fish biomonitors also have been among the first biomon- and bacteria). In higher organisms, behavior is the response itors utilized, especially for those systems based on rheotaxis type that generally is recorded with biomonitors. In microbes, [14], in which fish are anticipated to exhibit rheotaxis when physiological responses, such as bioluminescence, have been exposed to pollution waves. The fish then drift downstream to chosen as endpoints. Generally, these systems are part of a potentially more favorable conditions. This behavior can be streamside monitoring station that also includes the ability to seen as an avoidance reaction. This system, especially when detect and measure chemical and physical parameters. Chem- used with Leuciscus idus, is insensitive and generates ethical ical detection often is automated and can include detection of concerns because of the small size of the test aquaria [3]. known pollutants expected to be found as a result of accidental Modern systems are being developed that are based on tracking industrial spills or agricultural runoff. by video groups of fish, using larger aquaria, and recording swimming speed, turning rate, and swarm formation as test BIOMONITORS: STATE OF THE ART parameters. Moreover, some noncontact bioelectric systems Most bacterial biomonitors are based on recording respi- have been developed, recording ventilation rate, cough rate, ration (bacterial respirometers); however, some use bacterial heart rate, and swimming behavior of different test species growth (i.e., measure turbidity or cell density) or biolumines- [15,16]. Tropical electrical fish exhibit an electrical organ dis- cence via a luminometer [8,9]. Bioelectrodes (bioprobes) are charge that has been used in biomonitoring systems, but this being developed that measure photosynthetic activity of im- parameter is too variable for accurate monitoring of pollutants mobilized green algae or cyanobacteria. Bacterial biomonitors [17]. are useful for monitoring wastewater treatment processes and Smaller running waters are governed predominantly by ben- effluents. Several problems with these

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