Identifying and Handling Contaminantrelated Wildlife MortalityMorbidity Steve Sheffield

Identifying and Handling Contaminant-related Wildlife Mortality/Morbidity Steve Sheffield, Joe Sullivan, and Woody Hill

Introduction ► Wildlife biologists can encounter mortality and/or morbidity incidents in the field ► Mortality – incidence of death ► Morbidity – incidence of sickness/ill health ► Wildlife mortality/morbidity incidents can be natural, accidental, or result from disease or exposure to environmental contaminants

Environmental Contaminants ► Environmental contaminants include: § pesticides § metals/metalloids § organic chemicals § inorganic chemicals § pharmaceutical drugs § natural plant/animal toxins

Contaminant Impacts ► Understanding contaminant impacts involves examination of many parameters: § species (or higher taxa) involved § trophic level of the species involved § chemical(s) involved § route(s) of exposure § signs of intoxication § fate and transport through the environment § environmental compartment (media) involved § environmental persistence

Species Specific Hazards ► Not all contaminants pose the same hazard to all taxonomic groups of animals ► Factors involved include: § evolutionary status (detoxifying enzyme systems more advanced in mammals) § physical /chemical properties of the chemical (e. g. , lipid solubility, volatility, etc. ) § differing toxicities of chemicals § routes(s) of exposure § trophic level of the animal

Trophic Level Effects ► Possible effects of trophic level: § Bioaccumulation – chemicals accumulate in an animals faster than they can be metabolized and excreted § Biomagnification – results from bioaccumulation and biotransfer where tissue concentrations of a chemical moves up the food chain through two or more trophic levels

Factors to Consider ► Three factors to consider with discovery of a field mortality/morbidity incident suspected to be caused by environmental contaminants: (1) Time is of the essence! Generally, there is little time to plan/conduct a research study of the incident (2) Time available for collecting evidence such as tissue samples and/or other environmental media (plants, soil, water, sediment, air) may be hours to a few days (3) Chemicals decompose, tissues decay/dessicate, and carcasses are readily scavenged, all of which greatly affect time available for sampling

Chapter Objective ► Provide guidelines for wildlife biologists in the field to assess wildlife mortality/ morbidity incidents and sampling techniques useful in detection and documentation of environmental contaminants impacting wildlife

Environmental Contaminants ► Human activities have resulted in the pervasive and dynamic nature of contaminants in the environment ► Many different industries contribute to this contaminant load, including chemical, agriculture, mining, energy, electronics, pharmaceutical, pest control, and others ► Greatest number of wildlife mortality/ morbidity incidents have been reported for 2 specific categories of contaminants: § Anticholinesterase (anti-Ch. E) insecticides § Anticoagulant rodenticides

Routes of Exposure to Environmental Contaminants ► Oral § Primary consumption of contaminant § Secondary poisoning from consumption of poisoned prey item ► Dermal ► Inhalation ► Placental/Egg yolk

Possible Effects of Environmental Contaminants ► Lethal effects – death of the animal ► Sublethal effects – serve to debilitate an exposed animal; reduced survival, growth, and reproductive rates can occur from impacts on one or more bodily systems

Lethal Effects of Environmental Contaminants ► The full extent of wildlife mortality from contaminants is difficult to assess – wildlife species often are secretive, camouflaged, mobile, live in dense habitat ► Typical field studies often reveal low estimates of mortality because carcasses disappear rapidly

Difficulties in Conducting Field Studies ► Most animal carcasses disappear within 24 -48 hours; scavenging rate very high ► Exposed animals that become sick may move from area or otherwise disappear ► Exposed animals may not always demonstrate visible signs of morbidity ► Exposed animals may become more vulnerable to predation or other mortality factor as a result of exposure

Classes of Contaminants ► Metals/Metalloids ► Organic Chemicals ► Inorganic Chemicals ► Pharmaceuticals ► Pesticides ► Natural Plant/Animal Toxins

Metals ► Metals can be essential or non-essential; that is, they may or may not have biological function ► Non-essential metals are most hazardous to wildlife species; they can enter body and replace those which are essential ► Non-essential metals of most concern: Hg, Pb, Cd, Cr+6

Metalloids ► Metalloids are transitory between metals and non-metals ► Metalloids can be essential or non-essential; that is, they may or may not have biological function ► Non-essential metalloids are most hazardous to wildlife species; they can enter body and replace those which are essential ► Non-essential metalloids of most concern: As, Se

Organic Chemicals ► Organic chemicals are based on C-H pairs ranging from single carbon chains to multiple aromatic rings ► Organic chemicals of most concern are: organic solvents, ethylene glycol, petroleum products (PAHs), and polyhalogenated compounds (PCBs, PBDEs, PCDDs, PCDFs, PFOSs)

Inorganic Chemicals ► Inorganic chemicals are a diverse group that do not have carbon as their principal elements ► Includes 4 general groups: alkalis and chlorine, industrial gases, inorganic pigments, and industrial inorganic chemicals ► Two inorganic chemicals pose a particular hazard to wildlife species: cyanide and white phosphorus

Pharmaceuticals ► There is a wide diversity of pharmaceutical drugs, hormones, and related organic wastewater contaminants that pose a potential hazard to wildlife species ► Most of these prescription drugs have not been tested for effects on wildlife ► Two pharmaceutical drugs that have caused numerous mortality/morbidity incidents are sodium pentobarbital and diclofenac

Pesticides ► Pesticide – any substance or mixture of substances intended for preventing, destroying, repelling, or mitigating any pest ► Unique contaminant category – intentionally released into environment ► Specific classes of pesticides of major concern to wildlife include insecticides, herbicides, fungicides, fumigants, rodenticides, avicides

Pesticides (Insecticides) ► Most are neurotoxicants – target insect nervous system ► Four distinct groups of insecticides include: § chlorinated hydrocarbons (e. g. , DDT) § anti-cholinesterases (organophosphorus and carbamate compounds) § synthetic pyrethroids § other botanicals (e. g, nicotine, rotenone)

Pesticides (Herbicides) ► Herbicides are chemical compounds capable of either killing or severely injuring plants ► There at least 65 different broad classes and >22 different chemical groups of herbicides, including: (germination inhibitors, photosynthesis inhibitors, meristem inhibitors, contact action, auxin growth regulators, and foliar grass inhibitors

Pesticides (Fungicides) ► Fungicides derived from a wide variety of chemicals whose focus is to kill fungi ► There at least 36 different chemical groups of fungicides – a direct result of the great diversity of fungi ► There are 3 general types of fungicides: foliar, soil, and dressings

Pesticides (Fumigants) ► Fumigants are used to kill insects, nematodes, weed seeds, and fungi in soil as well as in stored grains, fruit, vegetables, clothes, and other products ► They usually are used in enclosed spaces due to the high volatility of the chemicals ► They generally are nonselective, highly reactive, and cytotoxic

Pesticides (Rodenticides) ► Rodenticides were developed to control pest small mammals (particularly rodents) ► They cam be categorized into several groups: § inorganic (metal-based) compounds (e. g. , thallium sulfate) § insecticides (e. g. , DDT) § natural plant toxins (e. g. , strychnine) § anti-coagulants (warfarin, brodifacoum, etc. )

Pesticides (Avicides) ► Avicides were developed to control avian pests, particularly flocking species such as European starlings, blackbirds, and pigeons ► Several different insecticides and other pesticides with avicidal properties have been used for this purpose

Natural Plant/Animal Toxins ► Natural plant and animal toxins are toxic chemicals of biological origin ► Produced by living organisms such as bacteria, blue-green algae, fungi, marine invertebrates and fishes, vascular plants, and poisonous aquatic and terrestrial animal species

Natural Plant Toxins ► Natural plant toxins – secondary plant compounds, some of which are used as the basis for pesticides (e. g. , nicotine, pyrethrum, rotenone, etc. ) ► Chemical groups which can be highly toxic include alkaloids, tannins, phenols, lectins, glycosides, and terpenes, among others

Natural Animals Toxins ► Three groups of microbial organisms (bacteria, algae, fungi) are capable of producing some of the most deadly toxins known ► Examples of this include: botulinum (bacteria), harmful algal blooms (blue-green algae in fresh and brackish waters, phytoplankton in marine waters, mycotoxins (fungi)

Contaminant Diagnostics - Safety ► Personal safety is a primary concern in a wildlife mortality/morbidity incident ► Field investigators should not handle carcasses, collect environmental samples, or enter the area of the incident until adequate safety precautions have been taken ► If contaminant is known, information can be found regarding its toxicity; if contaminant is unknown, only trained personnel should attempt to enter site for samples

Contaminant Diagnostics – Safety 2 ► Once contaminant(s) identified, proper protective clothing (including on feet and hands) for the contaminant(s) should be worn ► When retrieving carcasses or debilitated animals from water, impermeable gloves and rubber boots should be worn ► Depending upon the contaminant(s) involved, respirators and/or TYVEK suits may be required

Contaminant Diagnostics – Safety 3 ► In hot/humid weather, heavy protective wear can be dangerous, so work periods should be shortened to prevent heat stress ► A clean, shaded area should be provided where workers can remove protective wear, cool off, and get rehydrated ► If disease is suspected, the list of precautions not as extensive as for contaminants because diseases generally are more species-specific than contaminants

Contaminant Diagnosis – Initial Site Reconnaissance ► Three rules govern initiation of any wildlife mortality/morbidity investigation: Protect yourself and other involved (2) Obtain the best case history possible (3) Collect the best specimens possible (1) ► Handling and collection of specimens in the field will affect what the laboratory can (and cannot) do with them

Contaminant Diagnosis – Initial Site Reconnaissance 2 ► When possible, notify a wildlife veterinarian (or other trained personnel) and wait for their arrival prior to initiating the investigation ► It is critical to presume that there will be legal implications of the investigation and the cause may be a highly toxic or contagious agent ► Field notes and documentation that begin with initial stages of investigation are important

Contaminant Diagnosis – Initial Site Reconnaissance 3 ► Initial ID of chemical(s) causing the incident should be attempted if it can be done safely § Early ID of the contaminant can: dictate safety precautions needed § direct types of samples that should be collected § How samples should be handled ► If source and cause of incident are not obvious, field investigator should err on side of safety, collecting samples inclusively

Contaminant Diagnosis – Initial Site Reconnaissance 4 ► As a starting point to decide whether the cause is disease or contaminant-related, consider the species affected ► If a single species (or group of related species) is affected, disease more than likely involved; if many different taxa affected, contaminants more than likely involved ► Upon initial discovery of the wildlife mortality/morbidity site, the nearest wildlife contaminant expert should be contacted

Contaminant Diagnosis – Initial Site Reconnaissance 5 ► Mortality incidents – personal safety of utmost importance because if a contaminant is present in concentrations high enough to kill or debilitate wildlife, it may pose a health hazard to the field biologist ► In many cases, locating carcasses can be difficult and exposure to contaminants is obvious

Contaminant Diagnosis – Initial Site Reconnaissance 6 ► Once carcasses found, immediate goals are: § to prevent further deaths § identify the cause and source of contaminant involved ► The risk of contaminants to wildlife is dependent on: § toxicity § concentration § route of exposure

Contaminant Diagnosis – Initial Site Reconnaissance 7 ► Morbidity – discovery of sick (morbid) animals requires fast action to be taken ► Morbid animals may be able to fully recover if treated in time ► Prior to collecting morbid animals, destination must be identified and appropriate transport containers obtained ► Transportation and treatment of wildlife species usually require specific permits

Contaminant Diagnostics – The Wildlife Contamination Investigation ► Investigations of wildlife mortality/morbidity incidents suspected to be caused by contaminants should proceed as though the cause was unknown ► All factors must be checked or eliminated unless there is solid evidence to support specific conclusions ► Initial decision as to whether or not an incident is contaminant-related is a process of elimination

Contaminant Diagnostics – The Wildlife Contamination Investigation ► Document the incident with detailed field notes and photographs ► The investigator’s interpretation of the wildlife mortality/morbidity incident scene will affect the type, number, and location of samples taken and the analyses performed ► Wildlife mortality/morbidity incidents may be a result of illegal activities, thus has the potential to become a legal case

Contaminant Diagnostics – The Wildlife Contamination Investigation ► Important factors in interpretation of the incident scene include: § location § time and date of incident § species involved § # of dead and/or sick animals § rate of deaths § chance of continuing mortality/morbidity § clinical signs observed § climatic conditions

Field Procedures – Sample Documentation and Transport ► It is critical that samples collected in the field be handled properly to ensure that useable information can be obtained ► All samples should be properly bagged and labeled ► Label should include what type of specimen, location it was collected, sample date/time, name of person collecting the sample

Field Procedures – Sample Documentation and Transport ► Samples should be placed on ice in the field as some contaminants degrade quickly and tissues/carcasses can degrade quickly at warm temperatures ► Once samples are taken from the field, they should be hard frozen ► Samples for contaminant analysis should be transported frozen or on dry ice

Field Procedures – Sample Documentation and Transport ► Handling samples – techniques for handling field-collected samples can vary by contaminant type ► When animal tissues are collected, great care should be taken to avoid cross-contamination ► Tissues can be placed into plastic bags or small, sterile glass jars; larger samples can be placed in zip-lock bags

Field Procedures – Record Keeping ► A field log is useful to make entries regarding each sample collected for analysis ► Entries should include: § sample ID number § type of sample collected § name of site where collection occurred § date § name or initials of person collecting the sample

Field Procedures – Record Keeping ► Accurate record keeping is critical to documenting wildlife mortality/morbidity incidents ► The more detailed information provided on the field data sheet, the better the chances the investigator(s) of the incident will be able to understand what happened

Field Procedures – Sample Collection ► In addition to wildlife tissue samples, other environmental samples also are critical ► Environmental samples should be collected from the immediate area of where dead or debilitated animals are found ► Those experienced with site and contaminant types can provide advice on number of samples required and how far samples should be collected from the original site

Field Procedures – Sample Collection ► In addition to animal tissues, samples can be taken from other environmental media, such as: § Plant tissues § Soil § Water/sediment § Air

Laboratory Procedures – Residue Analysis ► Conducting residue analysis requires consideration of many factors, such as: § cost (generally expensive) § detection limits § QA/QC (quality assurance/quality control) § how to read and interpret the chemical analysis report § how to interpret the toxicological data

Laboratory Procedures – Residue Analysis ► Interpretation of residue analysis data can be tricky ► Overall, we know very little about how body residue levels of contaminants correlate to corresponding effects seen in wildlife species ► Correlating contaminant levels in the body (exposure) with an effect provides the most powerful use of residue analysis data

SUMMARY ► A wide variety and volume of chemical contaminants are found in the environment, and frequently have been shown to exert negative impacts (mortality, morbidity) on wildlife species ► As a result, wildlife mortality/morbidity incidents will occur ► There is a strong need for field biologists to be able to adequately identify and handle these incidents

SUMMARY - 2 ► Few field biologists receive training in environmental or wildlife toxicology, thus it is important that field biologists have a source for SOPs for successfully handling wildlife mortality/morbidity incidents ► This chapter provides field biologists with guidance on understanding wildlife toxicology and procedures that should be followed when confronted with a wildlife mortality/morbidity incident

“The dose makes the poison” Paracelsus THE END