Invertebrate

Invertebrate acute and chronic toxicity tests are usually carried out on earthworms Eisenia spp. The acute test is run according to OECD 207 [60] that observes mortality and biomass fluctuations after 2 weeks of exposure. According to OECD 222 [61], the reproduction test examines the growth and mortality of adult worms after 4 weeks exposure, and the number of offspring present in soil after a further 4 weeks. 

Drutschmann (1998, personal communication) observed a caloric content of 

5 kJ/g in imagos of the wax moth Galleria mellonella, a figure which is very near to that of fat. The content of growing larvae was significantly smaller with 

5 kJ/g in the first stages, 31.9 in the last larval stage and 34.2 kJ/g for the pupae. As Galleria pupae and imagos no longer feed this further energy concen- 

---

The bulk of global production from aquaculture is utilized directly as human food, with pubhc aquaculture playing a minor role in many nations or being absent. Private aquaculture is not only about human food production, however. There is, in some regions, weU-developed private sector aquaculture involved in the production of bait and ornamental fishes and invertebrates. 

Among the invertebrates, most of the world s production is associated with mussels, oysters, shrimp, scallops, and clams. Crawfish culture is of considerable importance in the United States, but amounted to only 24,211 metric tons in 1992 (4) insignificant compared to some other invertebrate species. 

Problems associated with excessive levels of nutrients and unwanted nuisance species have already been mentioned. There are cases in which intentional fertilization is used by aquaculturists in order to produce desirable types of natural food for the species under culture. Examples of this approach include inorganic fertilizer appHcations in ponds to promote phytoplankton and zooplankton blooms that provide food for young fish such as channel catfish, the development of algal mats through fertilization of milkfish ponds, and the use of organic fertilizers (from Hvestock and human excrement) in Chinese carp ponds to encourage the growth of phytoplankton, macrophytes, and benthic invertebrates. In the latter instance, various species of carp with different food habits are stocked to ensure that all of the types of natural foods produced as a result of fertilization are consumed. 

Environmental Considerations. The phosphate flame retardants, plasticizers, and functional fluids have come under intense environmental scmtiny. Results pubUshed to date on acute toxicity to aquatic algae, invertebrates, and fish indicate substantial differences between the various aryl phosphates (159—162). The EPA has summarized this data as well as the apparent need for additional testing (147). 

AH of the propylene glycols are considered to be practically nontoxic to fish on an acute basis (LC q < 100 mg/L) and practically nontoxic to aquatic invertebrates, also on an acute basis. Acute marine toxicology testing (38) on propylene glycol showed that the 96-h LC q for fathead minnows was 54,900 mg/L and the 48-h LC q for Daphnia magna was 34,400 mg/L. A 24-h NOEL of 50,000 mg/L was also observed for fingerling trout. Similar results were observed for guppies and rainbow trout (39). 

H. C. Evans, in R. A. Samson,. M. Vlak, and D. Peters, eds.. Fundamental and Applied Aspects ofi Invertebrate Pathology, Proc. 4th International... 

Several peptides are related in different ways to these classical opioid peptides. FMREamide (Phe-Met-Arg-Phe-NH2) contains the first four amino acids of enkephalin and is active in various invertebrates (58) FMREamide-related peptides also have been located in the mammalian brain. Although these... 

DDT is slowly converted in vivo by reductive dechlorination to DDD and by further dechlorinations to 4,4 -dichlorodiphenylacetic acid [83-05-6] (DDA), the predominant excretory metaboUte. Anaerobically, it may form 4,4 -dichlorodiphenyiacetonitrile [20968-04-1] (DDCN). However, most DDT that enters the environment is sequestered as DDE, which is ubiquitously present in the body Hpids of invertebrate and vertebrate animals. In humans. 

Phosphatic limestone is usually a high calcium type that contains appreciable percentages (up to 5%) phosphoms. It originates from invertebrate marine organisms. 

R. Eisler, Molybdenum Ha rds to Fish, Wildlife, and Invertebrates M Synoptic Keview, U.S. Fish and Wildlife Service Biology Report No. 85 (1.19), 1989,... 

Life cycle in aquatic invertebrates (daphnia/mycid)... 

Naturally occurring quaternary ammonium compounds have been reviewed (179). Many types of aliphatic, heterocycHc, and aromatic derived quaternary ammonium compounds are produced both in plants and invertebrates. Examples include thiamine (vitamin B ) (4) (see Vitamins) choline (qv) [62-49-7] (5) and acetylcholine (6). These have numerous biochemical functions. Several quaternaries are precursors for active metaboUtes. 

The threat of accidental misuse of quaternary ammonium compounds coupled with potential harmful effects to sensitive species of fish and invertebrates has prompted some concern. Industry has responded with an effort to replace the questionable compounds with those of a more environmentally friendly nature. Newer classes of quaternaries, eg, esters (206) and betaine esters (207), have been developed. These materials are more readily biodegraded. The mechanisms of antimicrobial activity and hydrolysis of these compounds have been studied (207). AppHcations as surface disinfectants, antimicrobials, and in vitro microbiocidals have also been reported. Examples of ester-type quaternaries are shown in Figure 1. 

Fig. 6. Approaches to minimising entrapment and impingement of fish and large aquatic invertebrates, eg, blue crabs, on trash screens at intakes, (a) An inlet pump house with vertical traveling screens mounted flush with a river shoreline to minimise obstmctions to animal movements (b) parallel flow to direct fish to a recovery chamber that returns to the water body (c) a velocity cap atop a vertical, offshore inlet induces a horizontal flow which fish avoid...

Unfortunately, there is a significant disadvantage resulting from appHcation of insect-resist agents from dyebaths it is impossible to ensure 100% exhaustion (transfer of pesticide from dyebath to fiber) and as a result, there is inevitably some environmental contamination. The extent of concern with this release of insect-resist agent depends on the spectmm of activity of the agent. If it is a broad-spectmm insecticide, especially one with reasonable persistence and lipophilic character, it is Hable to be reasonably toxic to aquatic insects and invertebrates, especially in certain environmental locations where... 

A relatively small number of studies have reported on the effects of cumene on plants, fish, and other organisms. Studies of the effects of cumene on fresh and saltwater fish indicate the lowest reported toxic concentration (LC q) for fishes was 20 to 30 mg/L (18). The solubiUty of cumene is about 50 mg/L (19). Among invertebrates, the lowest reported concentration that was toxic to test organisms was 0.012 mg/L after 18 hours (20). The only available data on the effect of cumene on aquatic plants indicate that the photosynthesis of several species was inhibited at concentrations from 9 to 21 mg/L (19). 

Few studies have been conducted on other invertebrate taxa but pentach-lorophenol exposure has been shown to affect daphnid reproductive capacity and sex steroid hormone metabolism and a high incidence of intersex has been observed in harpacticoid copepods near an Edinburgh sewage outfall. " ... 

Much basic research is needed on tests using invertebrates. 

In addition to reproductive effects, fish exposed to endocrine disrupters may have a decreased response to stress or decreased growth and metabolism which can affect their ability to survive, or to defend themselves against predators. All of these factors can affect the ability of the species to survive and to reproduce itself in sufficient numbers to maintain the stocks on which our commercial and sport fisheries are based. Not all fish species will be equally susceptible to the effects of endocrine disrupters. Selective sensitivity to such effects, especially those affecting reproduction, may well lead to major changes in the flora and fauna of some of our major aquatic ecosystems as the balance between fish, mammals, invertebrates and plants, and between predators and prey, is destabilised... 

Whilst the impact of xenoestrogens has been the most widely studied effect in vertebrates, it is unclear whether endocrine disruption in invertebrates proceeds... 

An appreciation of the extent to which invertebrate species may be exposed to such chemicals comes from considering the effects of complex mixtures. In the North Atlantic ecosystem alone, hundreds of pollutant chemicals have been identified. These include metals, synthetic and chlorinated organics and polycyclic aromatic hydrocarbons. Over 300 aromatic hydrocarbons have been detected in some regions of the Chesapeake Bay, and high concentrations of PCBs have been... 

Table 2 Chemicals suspected of causing endocrine disruption in invertebrate species...

Exposure to estrogenic compounds through diet will differ for herbivores and carnivores, the latter being most likely to encounter endogenous steroids in their prey. Efficient uptake of steroids in mammals is illustrated by the use of the contraceptive pill, but routes of absorption in invertebrates remain to be determined. The relationship between endocrine disruption and metabolic toxicity, with reduced reproductive viability a secondary consequence of metabolic disturbance, also merits further study in invertebrate species. 

The invertebrate phyla are often neglected in ecotoxicological testing protocols. A token invertebrate species such as the copepod Daphnia may be used to evaluate the effects on extremely diverse phyla. This neglects the diversity of biochemical and physiological functions that may render different phyla vulnerable to different classes of compound at different stages of their life cycles. 

---