the impact of the cyanamid canada co. discharges to benthic invertebrates in the welland river in...

Ecotox ico logy 2, 93-120 (1993)

The impact of the Cyanamid Canada Co. discharges to benthic invertebrates in the Welland River in Niagara Falls, Canada

M I K E D I C K M A N a n d G R A Z Y N A R Y G I E L

Biological Sciences Department, Brock University, St. Catharines, Ontario, Canada L2S 3.41

Received 15 July 1992; accepted 6 December 1992

In 1986, the International Joint Commission (IJC) recommended that the Niagara River watershed should be declared an Area of Concern (AOC). This IJC recommendation was ratified by the 4 signatories of the Great Lakes Water Quality Agreement. In order to delist an AOC, it is necessary to locate any areas of impairment within the watershed and carry out remediation projects that permit uses that were previously impaired. To this end we attempted to determine whether or not the sediments at 7 study sites near the Cyanamid Canada (Chemical) Co. were contaminated at levels that would result in the impairment of the natural biota which inhabit the watershed.

The Cyanamid Canada (Chemical) Co. discharges ammonia wastes, cyanide, arsenic and a variety of heavy metals into treatment systems which ultimately discharge to the Welland River, the major Canadian tributary to the Niagara River. This portion of the Welland River near the factory was designated a Provincially significant (Class one) wetlands by the Ontario Ministry of Natural Resources. In 1986, the mean discharge to a creek from Cyanamid Canada Co. was 27,342 m 3 per day (MOE, 1987). Similar discharge volumes occurred in 1989. In 1991, the total discharge was 25,000 m 3 per day (MOE, 1991).

The majority of the benthic invertebrates collected from the study area were pollution tolerant taxa (e.g., sludge worms constituted 68% of all the organisms collected). The lowest chironomid densities were observed at stations 1, 2, and 4, which were the only stations situated close to Cyanamid's discharge pipes. The absence, of clams and mayflies which burrow to greater depths than do chironomids and sludge worms, probably reflects the inability of the deeper dwelling burrowers to tolerate the contaminants which we recorded at these 3 stations. The absence of all crustaceans from these same 3 stations (stations 1, 2 and 4) when coupled with their low biotic diversity and the elevated heavy metal concentrations in the sediments were cause for concern. In addition, stations 2 and 4 displayed the highest frequency of chironomid mentum deformities.

Stations 1 and 2 were located near a pipe which was one of Cyanamid Canada Company's major discharge point sources to the Welland River until a court order in 1980 stopped the company from discharging toxic material to the Welland River via that pipe. Elevated levels of cobalt (10 times above background), molybdenum (6 times above background), nickel (8 times above background), tungsten (284 times above background) and zinc (20 times above background) near the abandoned discharge pipe were correlated with the presence of pollution tolerant chironomid taxa such as Polypedilum and Procladius. The highest sludge worm densities were also observed at the abandoned pipe site which was the only site where oily wastes were found in the sediments.

Among the 1,275 chironomids taken from the seven Cyanamid Canada stations, the great majority were pollution tolerant taxa. The low biotic diversity and the presence of considerable numbers of pollution tolerant benthic macroinvertebrates in combination with the chemical

0963-9292 © 1993 Chapman & Hall

94 Dickman and Rygiel

evidence of pollutants in the sediments near many of these Cyanamid discharge sites were reasons for classifying these sites as 'impaired' as defined by the International Joint Commission.

Keywords: contaminated sediment bioindicators; midge deformity frequencies

Introduction

For a number of years, the Cyanamid Canada (Chemical) Co. has been discharging cyanide, ammonia, urea, nitrate, phosphorus, chromium, nickel, zinc, and other chemicals into the Welland River via Thompson's Creek. Previous investigations (Dickman et al., 1983, 1992) indicated that sporadic discharges of electrolytes called 'shock loads' contained ammonia and chromium which contributed to the total pollution loading of the Welland River.

Elevated frequencies of chironomid menta (teeth) deformities have been correlated with the presence of teratogenic pesticides (Hamilton and Saether, 1971), carcinogenic heavy metals (Wiederholm, 1984), sediments contaminated by coal tars (Cushman, 1984; Dickman et al., 1992), sediment contaminated with radioactive material (Warwick et al., 1987) and vinyl chlorides (Lan et a/.,1990). Since aquatic communities are sensitive to teratogens and mutagens, many ecologists have attempted to use selected invertebrates such as chironomids and oligochaetes to quantify the level of teratogens in aquatic sediments (Warwick, 1985).

Chironomids are among the most widely distributed benthic invertebrates in fresh water, and their larvae represent a sensitive stage in their life cycle (Roback, 1978). Research on the frequency of chironomid larvae in polluted waters has led to the use of mouth part (mentum) deformities in the detection of teratogenic contaminants (Wiederholm, 1984; Warwick et al., 1987).

The mouthparts of chironomid larvae are normally fairly symmetrical. Deformed specimens are characterized by asymmetrical menta and mandibular structures. It was suggested that different types of deformities may be caused by different types of pollutants (Hamilton and Saether, 1971). The susceptibility to teratogens seems to differ among the various chironomid species, some species being far more sensitive to a particular teratogen than others (Wiederholm, 1984; Warwick et al., 1987). Many mutagenic and teratogenic substances accumulate in sediments. These sediments com- prise the major habitat of most benthic invertebrates (Buikeman and Herricks, 1978; Lafont, 1984). Although the absolute concentration of teratogenic pollutants may be very low in water, bioconcentration and bioaccumulation will serve to magnify them in the food chain (Buikeman and Herricks, 1978; Tarkpea et al., 1985).

Purpose

The International Joint Commission recommended that the Niagara River Watershed should be declared an Area of Concern. In the late 1980's this recommendation was ratified by the 4 signatories of the Great Lakes Water Quality Agreement. In order to delist an Area of Concern, it is necessary to locate any areas of impairment and carry out remediation projects that permit uses that were previously impaired. To this end we:

1. Conducted a biological analysis of all chirononomids at the seven study sites near the Cyanamid Canada Co.

2. Determined the density and generic richnes of benthic invertebrates at each of the seven study locations.

The impact of the Cyanamid Canada Co. discharges to benthic invertebrates

ONTARIO LAKE ~ h ¢ / ~ I

ST. ~l

Well WELLAND

NIAGARA FALLS

• Thompson's ~ ,

95

I N U.S.A

LOVE CANAL

I AGARA FALLS

FORT ERIE PORT COLBORN'

LAKE ERIE BUFFALO

scale: lcm=4.5 km

Fig. 1. A portion of Regional Niagara from near the headwaters to the mouth of the Welland River. The Welland Ship Canal is represented by the thick dark line which runs north to south across the width of the Niagara Peninsula and Cyanamid Canada Co. is represented by the hatched area in the circle located near the confluence of Thompson's Creek and the Welland River.

3. Compared our results with results obtained in previous studies of the Welland River.

Description of the study area

The Welland River is the major Canadian tributary to the Niagara River (Fig. 1). A portion of the Welland River which includes locations near the Cyanamid Canada Co. was designated by the Ontario Ministry of Natural Resources as a provincially significant (Class 1) riverine wetlands area. The Welland River flows eastward along the Niagara Peninsula into the Niagara River. Upstream of the city of Welland, the Welland river passes through agricultural areas. Downstream of the city of Welland, the Welland River passes through an industrialized area. Numerous studies on the sediments of the Niagara River watershed report on the presence of a number of types of volatile organic compounds (Kaiser and Combe, 1983; Lan et al., 1990) as well as heavy metals (Dickman, 1988).

Methods

Sampling methods

A Ponar dredge measuring 15 cm by 15 cm (225 cm 2) was used to remove the sediment samples. At least 2 Ponar replicate samples were collected from each site starting from


October 1991 and ending in February, 1992. Sufficient samples were taken to obtain enough chironomid larvae for statistical analyses.

The dredged sediments were transferred to a bucket equipped with a 0.75 mm mesh sieve at its base. In the laboratory, samples were sorted and then preserved in a 95% ethanol solution. Two vials were used for each site, one for chironomids and the other for all other invertebrates. Chironomids were identified to the generic level because there are few if any taxonomic keys or references to permit species identifications of the majority of chironomid larvae.

To facilitate chironomid mentum abnormality frequency assessments, each chironomid head capsule was separated from its body and soaked in 10% KOH solution for 24 h. Following this, the chironomid head capsules and menta were rinsed with distilled water and mounted in Canada Balsam on standard glass microscope slides. Each mentum was evaluated for the presence of deformities.

A total of 7 stations were sampled near Cyanamid (Fig. 2). Stations 1, 2, and 3 were in areas within the Welland River. Station 4 was located on Thompson's Creek, the company's major point source discharge to the Niagara River watershed. Station 5 was located where surface waters and runoff from the northern edge of the plant discharge into Thompson's Creek. Stations 6 and 7 were situated along Thompson's Creek with station 7 being closest to the mouth of the Welland River.

Sediment chemistry Thirteen sediment samples (3 from sites 1, 2, 4 and 6 and one from the control site) were removed from Thompson's Creek and the Welland River in March of 1992. All of these samples were sent to Becquerel labs (Mississauga, Ont.) for neutron activation analysis of 34 elements found in the sediment (Table 1).

Sediments were dried, pulverized and mixed so that their mineral content could be determined by neutron activation analysis. The neutron activation analysis technique used in this study exposed the dried sediment to a flux of neutrons that was generated in the McMaster University nuclear reactor. The resulting radioactive isotopes emit gamma rays whose energies and wavelengths are characteristic of each particular element in the sample. A germanium crystal held at liquid nitrogen temperature was used to monitor

¢,

..... ii!i!ii/iiiiiili!ili/i!ili / Thom sons Oroek

i~"---~----~Recoverv zone confluence of zone ec0very zone TTwPe~lOn, d RC~ve:it h

Fig. 2. The 7 sampling sites located near Cyanamid Canada Co.

The impact of the Cyanamid Canada Co. discharges to benthic invertebrates 97

the gamma radiation. Multichannel voltage analyzers were used to sort out the voltage pulses from the germanium crystal and these pulses were used to generate spectra. By comparing spectral peak positions with 'library' standards, the elements comprising the samples were qualitatively and quantitatively identified.

Results

To evaluate the neutron activation analyses of the Cyanamid sediment samples we used standard texts by Bowen (1979), Sax (1984) and Thornton (1983). These texts provided information on normally encountered levels of these elements in soils and in living organisms. We then compared the mean concentrations found in the Cyanamid sediments with concentration ranges in uncontaminated soils (Bowen, 1979; Thornton, 1983). Information from Dangerous Properties of Industrial Materials (Sax, 1984) was used to evaluate the potential impact of the element in question on the biota observed at each site.

The cobalt concentration at site 1 was 475 ppm, which was about 10 times above normal. The amount of cobalt in soil ranges from 1 ppm to 40 ppm (Thornton, 1983). The LDs0 o f cobalt is 55 mg kg -1 (Sax, 1984).

Molybdenum at sites 1 and 2 was found at 665 ppm and 123 ppm, respectively. Molybdenum is classified as an essential trace element and appears in soil normally at 2 ppm (Thornton, 1983). In metal-rich soils, its concentration varies from 10 ppm to 100 ppm (Bowen, 1979). At the concentrations observed at sites 1 and 2, molybdenum (Mo) can be the cause of molybdenosis or hypocuprosis in cattle. In doses of 70 mg kg -1 for rabbits (intratracheal route) it causes death (lowest lethal dose LDLo = 70 mg kg-1). The lowest published toxic dose in humans is 6.1 mg kg -1 after a chronic exposure period of 35 weeks (Sax, 1984).

Nickel at station 1 was observed at a concentration of 810 ppm. For comparison, in normal soil it ranges from 2 ppm to 100 ppm (Thornton, 1983). Elevated levels of this essential trace element is associated with observed cases of toxicity in cereal and other grain crops. In addition, nickel has been reported to be carcinogenic in both humans and animals (Sax, 1984). The LDLo is 5 mg kg -1 (pigeon - digestion route).

Tungsten occurs at 92 ppm at station 1. In average soils, tungsten is not a common element. It appears in limestone-rich soils at approximately 0.5 ppm (Thornton, 1983). Tungsten is considered somewhat more toxic than molybdenum (Sax, 1984). Heavy exposure to tungsten-laden dust or the ingestion of large amounts of the soluble compounds containing tungsten produces mortality in experimental animals. The TDLo is 1.2 mg kg -1 over 35 weeks when tungsten is ingested daily by rats (Sax, 1984).

Zinc at station 1 was 507 ppm. Generally, the concentration of this trace element in soils ranges from 20 ppm to 200 ppm (Thornton, 1983). Elevated levels of zinc are associated with toxicity in cereal crops. It is a cause of skin and eye irritation in humans and fatalities have resulted from lung damage caused by the inhalation of zinc chloride fumes (Sax, 1984).

Arsenic at site 2 was 12.3 ppm. The level in soil ranges from 1.5 ppm to 7.5 ppm (Thornton, 1983). Arsenic is classified as a highly toxic element with carcinogenic and teratogenic properties. The toxicity level of arsenic to microorganisms is 3.3 ppm (Sax, 1984). The lowest published lethal dose (LDLo) when given orally to guinea-pigs is 10 mg kg -1.


Table 1. (a) Neutron activation analysis of sediments taken from Cyanamid sites 1 and 2 a

Element DL Control Site 1 Site 2 site (old discharge pipe) (downstream from site 1)

Mean Std Std Mean Std Std dev. error dev. error

Antimony 0.10 0.5 1.04 0.35 0.2 0.72 0.13 0.07 Arsenic 0.50 9.4 7.83 2.23 1.28 9.9 2.7 1.56 Barium 50.0 410.0 253.3 25 14.5 486 25.17 14.53 Bromine 0.50 3.7 6.9 1.38 0.79 2.87 0.58 0.33 Cadmium 5.0 <5.0 <5.0 <5.0 Cerium 5.0 100.0 47.67 14.1 8.1 130 0 0 Cesium 0.50 4.8 1.6 0.1 0.058 5.03 0.35 0.20 Chromium 20.0 98.0 283.3 81.5 47.02 187 25.17 14.53 Cobalt b 5.0 21.0 475 108 62.5 35.0 4.0 2.31 Europium 1.0 1.8 1.2 0.02 0.115 2.3 0.17 0.1 Gold, PPB 2.0 <2.0 6.53 2.49 1.4 3.13 2.73 1.58 Hafnium 1.0 7.2 4.3 1.02 0.59 7.83 0.99 0.57 Iridium, PPB 50 <50.0 <50.0 <50.0 Iron (%) 0.20 4.8 2.9 0.8 0.46 5.9 0.36 0.21 Lanthanum 2.0 44.0 19.33 3.51 2.03 55.0 3.61 2.08 Lutetium 0.20 0.79 0.22 0.2 0.115 1.0 0 0 Molybdenum b 1.0 <1.0 66__._55 212 122.6 9.57 3.39 1.96 Nickel b 10.0 30.0 810 163.0 94.52 59.0 7.94 4.58 Rubidium 5.0 130.0 39.67 3.06 1.76 120.0 10.0 5.77 Samarium 0.1 5.7 3.43 0.40 0.23 8.2 0.2 0.12 Scandium 0.2 18.0 6.9 1.87 1.08 19.5 1.8 1.04 Selenium 5.0 <5.0 <5.0 <5.0 Silver 2.0 <2.0 0.9 1.56 0.9 <2.0 Sodium 0.02 1.1 0.68 0.07 0.04 1.27 0.06 0.03 Tantalum 0.5 1.0 0.19 0.34 0.19 1.07 0.12 0.067 Tellurium 10.0 12.0 <10.0 <10.0 Terbium 0.5 0,9 0.83 0.32 0.19 1.1 0.1 0.058 Thorium 0.2 10.0 4.6 0.7 0.40 12.0 1.0 0.577 Tin 100 <100.0 <100.0 <100.0 Tungsten b 1.0 2.1 92.0 19.5 11.27 3.1 1.65 0.95 Uranium b 0.2 2.9 6.13 1.17 0.67 3..___00 0.1 0.058 Yttrium 1.0 4.0 1.97 0.71 0.41 4.6 0.61 0.35 Zinc b 100 140.0 506.0 109 63.33 176 15.28 8.82 Zirconium 200 <200.0 70.0 121 70.0 243 215.4 124.4


Table 1. (Continued). (b) Neutron activation analysis of sediments taken from Cyanamid sites 4 and 6 a

Element DL Control Site 4 Site 6 site (Thompson's Creek (Thompson's Creek at

crosses Garner Road) Chippawa Creek Road)

Mean Std Std Mean Std Std dev. error dev. error

Antimony 0.10 0.5 1.17 0.12 0.07 0.58 0.02 0.01 Arsenic b 0.50 9.4 12.3 1.16 0.67 9.67 0.58 0.33 Barium 50.0 410 473.3 47.26 27.29 480.0 26.46 15.28 Bromine b 0.50 3.7 12.0 1 0.58 5.23 0.67 0.38 Cadmium 5.0 <5.0 <5.0 <5.0 Cerium 5.0 100 105.6 12.50 7.22 130 10.0 5.77 Cesium 0.50 4.8 4.13 0.64 0.37 3.73 0.15 0.09 Chromium 20.0 98.0 143.3 15.28 8.82 102.6 6.43 3.71 Cobalt 5.0 21.0 28.67 3.06 1.76 34.33 0.58 0.33 Europium 1.0 1.8 1.97 0.67 0.38 2.8 0.5 0.29 Gold, PPB 2.0 <2 7.3 1.51 0.87 <2.0 Hafnium 1.0 7.2 7.6 0.61 0.35 8.97 1.05 0.61 Iridium, PPB 50 <50.0 <50.0 <50.0 Iron (%) 0.20 4.8 5.77 0.61 0.35 5.4 0.17 0.1 Lanthanum 2.0 44.0 44.0 5.0 2.89 48.67 4.04 2.33 Lutetium 0.20 0.8 0.74 0.07 0.04 0.88 0.9 0.05 Molybdenum b 1.0 <1.0 <1.0 <1.0 Nickel b 10.0 30.0 85.67 6.11 3.53 51.67 8.51 4.91 Rubidium 5.0 130.0 99.67 10.02 5.78 95.0 5.0 2.89 Samarium 0.1 5.7 5.63 0.6 0.35 7.57 0.45 0.26 Scandium 0.2 18.0 16.33 1.53 0.88 16.33 1.16 0.67 Selenium 5.0 <5.0 <5.0 <5.0 Silver 2.0 <2.0 <2.0 <2.0 Sodium 0.02 1.1 1.03 0.16 0.09 1.47 0.06 0.03 Tantalum 0.5 1.0 0.95 0.08 0.05 0.97 0.06 0.03 Tellurium 10.0 12.0 <10.0 <10.0 Terbium 0.5 0.9 0.8 0.1 0.06 1.07 0.15 0.09 Thorium 0.2 10.0 9.1 0.85 0.49 9.6 0.69 0.04 Tin 100 <100 <100.0 <100.0 Tungsten 1.0 2.1 1.43 1.24 0.72 1.37 1.19 0.68 Uranium b 0.2 2.9 2.87 0.64 0.37 2.77 0.12 0.07 Yttrium 1.0 4.0 3.5 0.46 0.27 4.33 0.46 0.27 Zinc 100 183.3 28.87 16.67 216.6 132.7 76.67

140.0 7 9 Zirconium 200 <200 256.7 234.6 135.4 303.3 47.26 27.29

aDL, detection limit; Std. dev., standard deviation; Std error, standard error; bold type, concentrations of an element elevated above background; Mean, calculated on the basis of three samples. bElements which appear at elevated levels.


Station 1 Station i was situated in the Welland River area approximately 1.5 km downstream from the B.F. Goodrich discharge and about 0.5 km upstream of Garner Rd. (Fig. 3). This station was located near a pipe which was one of Cyanamid Canada Co.'s major discharges until a court order in 1980 stopped the company from discharging toxic ammonia to the Welland River. Station 1 was subdivided into three subsites:

subsite 1A - 7 m upstream from the abandoned discharge pipe, subsite 1B - at the abandoned discharge pipe, subsite 1C - 10 m downstream from the abandoned discharge pipe.

Eighteen Ponar samples were taken at station 1, 10 were taken on October 1, and 8 on October 8, 1991.

Subsite 1A - Six Ponar dredges were taken approximately 7 m upstream from the pipe. Samples were composed of sand and organic matter and were taken in front of Typha. Subsite 1B - 5 Ponars were taken at the end of the pipe. Some patches of white and gray coloured sediments were observed at station lB. At 1.5-2 m from shore the bottom of the river was covered with filamentous green algae (Cladophora). When the Ponar penetrated the sediment surface, coloured rings of oil were observed. Subsites 1C and C* - 7 Ponars were taken 10 m downstream of the pipe. During the sorting process a faint 'oily' smell was noted. Along the bank at subsite C*, aquatic plants such as cattails, algae and Canada water weeds were found. This subsite is represented on Fig. 3 as C*. Oligochaetes comprised 97% of the invertebrates observed at subsite C* (Tables 2 and 3).

The total invertebrate density at station 1 exceeded 8,780 m -2. The highest invertebrate density (primarily oligochaetes) occured at subsite 1C. The lowest invertebrate density was observed at subsite 1B, the site situated closest to the abandoned pipe. Subsite 1B displayed the highest density of chironomids.

The most abundant chironomid taxa at station 1 were Polypedilum and Procladius. Chironomids from subsites 1A and 1C did not display any labial plate deformities. At subsite 1B, chironomid labial plate deformities represented 5.6% of the total. Only one taxon, Phaenopsectra, displayed mentum deformities at this subsite. At station 1, 62 chironomids were collected and only 1.6% of these displayed mentum deformities (Figs 4 and 5).

Station 2

Station 2 was half a kilometer downstream from station i near a Cyanamid surface water run-off drainage pipe. The entire effluent from this Cyanamid surface drainage pipe went directly into the Welland River. Subsite locations from this area are indicated in Fig. 6.

A total of nineteen Ponar samples were taken from station 2 (Fig. 6). Ten were taken on October 29 and nine on November 3, 1991.

Subsite 2A - This site was located 0.5 m from the shore and approximately 0.5 m downstream from the discharge pipe. Eight Ponar samples were taken at this subsite. The sediment consisted mainly of clay and silt mixed with small amounts of organic matter. Close to the shore, there were dense stands of cattails, plus a few bushes and trees. The depth of the water was 0.1 m. Subsite 2B - This location was 2.5 m downstream from the pipe and approximately 2 m from shore. Six Ponar samples were taken from this subsite. The sediment was composed

The impact of the Cyanamid Canada Co. discharges to benthic invertebrates

Table 2. Total invertebrate data at station 1. a

101

Subsite 1A Subsite 1B Subsite 1C Total Invertebrate No. Density No. Density No. Density No. Density

Amphipoda 0 0 2 18 6 24 8 20 Coleoptera

Hydrophilidae 0 0 0 0 (1) 4 0 0 Diptera

Chironomidae 20 148 18 160 10 + (14) 97 62 153 Culicoidae 3 22 2 18 3 + (12) 61 20 49

Halacaridae Hydrocarina 0 0 0 0 (1) 4 1 3

Hirudinae 0 0 3 28 2 + (4) 24 9 22 Isopoda 0 0 2 18 (1) 4 3 7 Oligochaeta 785 5815 252 2418 113 + (2300) 3450 6049

15321 Trichoptra 1 7 1 9 0 0 2 5

Total 809 5993 280 2489 2467 1566 3556 8780

aNumbers in parentheses represent data from subsite C*.

Welland River

10

l C

.5 km

Property of Cyanamid

Rd

0.5 km

~ . ~ Scale: 2 cm = 6 m

Fig. 3. Sampling locations 1A-C upstream and downstream of station 1. Stands of Cattails are represented by hash marks in this and subsequent figures.

102

Table 3. Total chironomid data at station 1. a

Dickman and Rygiel

Genus

Subsite 1A Subsite 1B Subsite 1C Total upstream aband, pipe downstream N D N D N D # % def. Den.

Clinotanypus 0 0 2 0 2 0 4 0 10 Cricotopus bicinctus 1 0 2 0 2 0 5 0 12 Cryptochironomus 2 0 0 0 2 0 3 0 7 Dicrotendipes 1 0 1 0 1 0 3 0 7 Einfeldia 6 0 0 0 1 0 7 0 17 Natarsia baltimore 0 0 1 0 0 0 1 0 3 Paratanytarsus 0 0 6 0 2 0 8 0 20 Phaenopsectra 0 0 0 1 2 0 3 (1) 33% Polypedilum halterale 8 0 3 0 7 0 19 0 47 Procladius 2 0 2 0 5 0 9 0 22

Total 20 0 17 1 24 0 62 (1) 1.6% Number of Ponars 6 5 7 18 Chironomid density 148.1 160.0 152.4 153.1 % deformities 0% 5.6% 0% 1.6%

'W is the number of normal chironomids; D is the number of deformed chironomids; % def. is the deformity frequency as a % of the total number of chironomids; Den. is the density (number of individuals per mE).

of a very hard clay. A dense stand of cattails formed a wide landing that extended approximately 1.8 m from the shore. The depth of the water varied f rom 0.5 m to 1.0 m. Subsite 2C - This subsite was located 5 m downstream from the surface run-off discharge pipe (depth of the water, 1.0 m). A total of five Ponar dredge samples were collected f rom this location. Sediment samples were composed primarily of sand and gravel. A variety of aquatic vegetat ion (Elodea, Cladophora, Characeae, Potamogeton pectinatus and Myriophyllum) were found. Data from station 2 are presented in Tables 4 and 5.

200

100

1. Natarsia baltimore ]- 100 [%] 2. Clinotanypus I 3. Cricotopus bicinctus 4. Cryptochironornus [] 5. Dicrotendipes 6. Einfeldia [ ] 7. Paratanytarsus " 50 8. Phaenopsectra 9. Polypedilum halterale =~

10. Procladius 1 ~ 11. total o

_ = i i = = I I I I II

1 2 3 4 5 6 7 8 9 10 11 genera

density deformity

Fig. 4. Chironomid density (number per m 2) is represented by solid bars, and the frequency of deformities by striped bars for each genus collected at station 1.


[%] 12.0 / '2 • % deformity [#]

10.0 ] [ ] gen. richness

8.0- = ~

, C E 6.0 u O '~

4 . 0 ' = Q P

2.0 o~

0.0 1 A 1 B 1 C Total sites

Fig. 5. Percentage of deformities (solid bars) and the generic richness (striped bars) for the three subsites at station 1.

2 C • 5 m from pipe St~ion 3 \ \ 0.5 km 0.5 km ~ S t a t i o n 1

\ \ 2 m from shore ~ / Welland "

River Rd.

] ~ Cyanam,d Property Scale: 2cm=5 m I

N Fig. 6. Sampling locations 2A-C at station 2.

[%] 20 20 [#]

>,,

E .9o 10 0

• % deformity [ ] gen richness

e- e-

0

q ) e -

0 2A 2B 2C Total

site

Fig. 7. Chironomid generic richness and percentage deformities at station 2.


Table 4. Total invertebrate data at station 2.

Invertebrate

Subsite 2A Subsite 2B Subsite 2C Total downstream downstream downstream

0.5 m from pipe 2.5 m from pipe 5.0 m from pipe No. Density No. Density No. Density No. Density

Amphipoda 6 33 6 44 9 80 21 49 Diptera

Chironomidae 31 172 48 356 42 373 121 283 Ceratopagonidae 4 22 6 44 3 27 13 30

Eulamellibranehia 0 0 1 7 4 36 5 11 Ephemeroptera 1 6 2 15 0 0 3 7 Hirudinae 4 22 4 30 2 18 10 23 Isopoda 3 17 14 104 2 18 19 44 Oligochaeta 125 694 101 748 278 2471 504 1179 Plecoptera 0 0 0 0 3 27 3 7

Total 174 967 182 1328 353 3049 699 1635

Table 5. Total chironomid data at station 2.

Subsite 2A Subsite 2B Subsite 2C Total Genus N D N D N D No. % def. Den.

Chironomus 0 0 3 1 0 0 4 (1) 25 9 Clinotanypus 0 0 1 0 1 0 2 0 5 Cryptochironomus 2 0 5 0 1 0 8 0 19 Paratanytarsus 0 1 0 0 1 0 2 (1) 50

5 Phaenopsectra 0 1 0 0 0 0 1 (1) 100

2 Polypedilum 17 2 18 3 25 0 65 (5) 7.7

152 Procladius halterale 8 0 16 1 13 0 38 (1) 2.6

89 Tanypus 0 0 0 0 1 0 1 0 2

27 4 43 5 42 0 Total number of chir. 31 48 42 121 (9) 7.4

283 Number of Ponars 8 6 5 19 density 172 364 373 283 % deformity 12.9% 10.4% 0 7.4%


Oligochaetes and chironomids were the dominant invertebrates at station 2. During the sampling period, crustaceans and ephemeropterans appeared in relatively low numbers (Table 3). Average invertebrate density was 1,635 m -2. Invertebrate density was highest, 3,049 m -2, at subsite 2C.

The numbers in parentheses at the far right (the fifth column) represent the number of deformed chironomids. Chironomid density was lowest at subsite 2A, which was situated closest to the pipe. Nine out of 121 chironomids (7.4%) at station 2 had deformed menta.

The highest rate of mentum deformities (12.9%) occurred at subsite 2A (Fig. 7). The density and generic richness at this subsite were lower than at all other sampling locations. Subsite 2B had the second highest per cent of chironomid mentum deformities (10.4%). At subsite 2C, where the abundance of aquatic vegetation was high, no chironomid mentum deformities were observed (Fig. 7). This subsite was characterized by the highest chironomid density. The most abundant genera of chironomids at all three subsite were Polypedilum and Procladius. These genera are referred to as pollution tolerant taxa (Warwick et al., 1987). Polypedilum displayed the highest rates of deformities of any of the genera at station 2.

- • • . . • flow-Welland River tation 3

I""-- I ~ 0.5 km -s ta t ion 2 private property ~

River Rd.

". l!llc-I ,L s c a l e - - l O O m

Fig. 8. Location of the recovery zone at station 3.

Station 3 This station was situated approximately 0.5 km downstream from station 2 (Fig. 8). Sediment at this station was characterized by substantial quantities of decomposing organic matter associated with dense stands of cattails growing along the river's edge. Close to the shore, the sediment was very soft and composed of mud laced with cattail (Typha) rhizomes. The most abundant submersed aquatic plant was water milfoil (Myriophyllum).

Five Ponar samples were taken on November 14, 1991, approximately 3 m from the shore (the depth varied from 0.5 m to 0.1 m, Tables 6 and 7). The dominant taxa at station 3 were the chironomids (density = 1,591 m -2, Table 6). Oligochaete density was lower here in comparison with the upstream sampling stations, i.e., stations 1 and 2.

Only 2 out of 179 (1.1%) chironomids taken from this station displayed mentum deformities (Fig. 9). The great majority of chironomids collected at station 3 belonged to the genus Polypedilum (53%, Table 7).


> ,

e- Q "O

2000

1000

• density • deformity

20 [%1

1. Clinotanypus 15 ~ 2, Chironomus

3. Cryptochironomus .~ 4. Dicmten6ipies

5. Einfeldia 10 ~ 6. Glyptotendipies

7. Polypedilum E 8. Procladius

5 ~, 9. Total o D.

0 ~

1 2 3 4 5 6 7 8 9 name of genera

Fig. 9. Chironomid density (solid bars) and percentage of deformities (striped bars) for each genus at station 3.

Table 6. Total invertebrate data at station 3.

Invertebrate No. of indiv. Total density (m -2)

Amphipoda 8 71 Diptera

Chironomids 179 1591 Ceratopagonidae 4 36

Hirudinae 2 18 Isopoda 8 71 Oligochaeta 43 382 Plecoptera 1 9

Total 245 2178

Table 7. Chironomid data at station 3.

Total Genus N D No. % def. Den.

Chironomus 27 1 28 (1) 3.6 249 Clinotanypus 4 0 4 0 36 Cryptochironomus 20 0 20 0 178 Dicrotendipies 15 1 16 (1) 6.3 142 Einfeldia 1 0 1 0 9 Glyptotendipies 1 0 1 0 9 Polypedilum halterale 91 0 91 0 809 Procladius 18 0 18 0 160

Total 177 2 179 (2) 1.1 1591 Number of Ponars 5 Density 1591 % of deformities 1.1


Station 4

Twenty one Ponar samples were collected from five subsites at station 4 in Thompson's Creek on February 3, 1992. Seven Ponar samples were taken from subsite 4A, where the sediment was composed mainly of yellow clay and gravel. Even in the middle of summer, there was no aquatic vegetation at station 4A. Sediment at subsite 4B consisted of silt and gravel. During the sorting process, decomposed leaves, roots and branches were found. Three Ponar samples were taken at this subsite. Subsite 4C was situated close to the bridge across Garner Rd. From this location, we obtained some empty snail shells, and stems of aquatic plants (e.g., Elodea). The depth of the water at all of these subsites was approximately 0.2-0.5 m. From the other side of Garner Rd. two additional subsites were chosen, subsite 4D and 4E (Fig. 10). Sediment from these two subsites consisted of yellow clay and silt. No aquatic plants (except some semi-terrestrial sedges growing close to the shore) were noted. The depth of water at these subsites was very shallow and ranged from 0.1 m to 0.2m.

A total of 260 chironomids and 915 other invertebrates were collected from all subsites at station 4. Oligochaetes and chironomids were the most abundant taxa at this station (Tables 8 and 9). Subsites situated closest to the artificial lagoon (4A and B, Fig. 10) had the lowest chironomid and invertebrate densities.

The average chironomid mentum deformity frequency at station 4 ws 5%. It was highest (8.6%) at subsite 4B. The most abundant chironomid taxa were Procladius (38%) and Paraphaenocladius (18%). Procladius was abundant at each subsite except subsite 4E while Paraphaenocladius was found mainly at subsite 4E.

•:•__1 station 2

N5

QI

3

Q.

stat ion 5

Gamer Rd. continue

scale: lcm=20m

Fig. I0. Subsites 4A-C at station 4.

oo

Tab

le 8

. In

vert

ebra

te d

ata

at s

tati

on 4

.

Sub

site

4A

S

ubsi

te 4

B

Sub

site

4C

S

ubsi

te 4

D

Sub

site

4E

T

otal

In

vert

ebra

te

No.

D

en.

No.

D

en.

No.

D

en.

No.

D

en.

No.

D

en.

No.

D

en.

Bas

omm

atop

hora

0

0 0

0 3

33

0 0

0 0

3 6

Col

eopt

era

Hyd

roph

ilid

ae

0 0

0 0

0 0

1 9

0 0

1 2

Dip

tera

C

hiro

nom

idae

28

17

9 35

51

8 57

63

3 93

47

10

44

260

550

Cer

atop

agon

idae

95

74

17

8 24

4 12

5 T

aban

idae

0

0 0

44

6 H

irud

inae

0

0 0

178

11

Odo

nata

0

0 33

0

6 O

ligo

chae

ta

Tot

al

15 0 0 0

172

1092

215

1365

5 0 0 0 12

8 18

96

168

2489

16 0 0 3

156

1733

235

2611

827

12

107

11

1 9

2 1

9 4

0 0

0 40

7 31

2 36

18

6933

515

376

4578

83

56

59 3 5 3

1175

24

87

1509

31

94

Tab

le 9

. C

hir

on

om

id d

ata

at s

tati

on

4.

Su

bsi

te 4

A

Sub

site

4B

S

ubsi

te 4

C

Sub

site

4D

S

ubsi

te 4

E

To

tal

Gen

us

No.

D

en.

No.

D

en.

No.

D

en.

No.

D

en.

No.

D

en.

No.

%

def

. D

en.

©

Con

chap

elop

ia

1 0

2 0

5 0

7 0

2 0

17

0 36

C

rico

topu

s bi

cinc

tus

5 1

0 0

1 0

0 0

0 0

7 14

.3

15

Cri

coto

pus

isoc

ladi

us

11

0 0

0 0

0 0

0 11

0

23

Cry

ptoc

hiro

nom

us

1 0

0 0

0 0

0 0

0 0

1 0

2 D

icro

tend

ipes

0

0 0

1 0

0 2

0 0

0 3

33.3

6

Nat

arsi

a ba

ltim

ore

1 0

0 0

2 0

10

0 2

0 15

0

32

Par

apha

enoc

ladi

us

1 0

1 0

3 0

2 0

37

3 47

6.

4 99

P

arat

anyt

arsu

s 0

0 0

0 0

0 0

0 1

0 1

0 2

Pha

enop

sect

ra

0 0

0 0

10

2 3

0 1

0 16

12

.5

34

Pol

yped

ilum

hal

tera

le

4 0

10

2 9

1 16

0

1 0

43

7.0

91

Pro

clad

ius

3 0

18

0 23

1

51

2 0

0 98

3.

1 20

7

27

1 31

3

53

4 91

2

44

3 T

ota

l n

um

ber

of

chir

. 28

34

57

93

47

26

0 5

550

Nu

mb

er o

f P

on

ars

7 3

4 5

2 21

D

ensi

ty

178

519

633

827

1044

55

0 %

of

def

orm

itie

s 3.

6 8.

6 7.

0 2.

1 6.

3 5

C~

~°


Flow of \ \ 5 C Thompsons's

Creek ~ Gamer Rd, continue

g

5A

scale 1 ~ =m = 5m

Fig. 11. The four sampling locations 5A-D at station 5.

~ N

Station 5 Station 5 (Fig. 11) was referred to as our 'upstream control' site. Some of the effluent at this station collects from surface runoff from the northern edge of the Cyanamid property, and therefore the site cannot really act as a control in the true sense of the word. Thirteen Ponar samples were taken from this station on December 2, 1991. Thompson's Creek was characterized at this site by very shallow water (0.05-0.15 m). The width of the stream was approximately 1.2 m, but in some places it was only 0.35 m wide (subsites 5C and 5D).

Sediment was composed of mud intermixed with organic matter at subsites 5B, 5C, and 5D. Typha occurred along both banks of Thompson's Creek at this station. On the other side of Garner Rd. (subsite 5A, Fig. 11) the sediment consisted mostly of sand and gravel.

Macroinvertebrate taxa and abundance (Table 10) and chironomid species abundance and deformity frequencies at the 4 subsites comprising station 5 are provided in Table 11. The most abundant taxa at station 5 were oligochaetes and chironomids. Invertebrate density exceeded 3,306 individuals m -2. Compared with the other 6 study stations, chironomid generic richness was highest at station 5 (13 taxa). Furthermore, chironomid species composition was quite different at station 5 compared with the other locations. The common taxa at all the other stations such as the pollution tolerant Polypedilum and Procladius were absent at Station 5. Instead, Cricotopus isocladius and Psectrotanypus were the two dominant taxa at this station.

Station 6 Station 6 was situated in Thompson's Creek, about 2 km downstream from station 3 and approximately 350 m from the confluence of Thompson's Creek and the Welland River (Fig. 12). Two Ponar dredge samples were collected on February 5, 1992 from this area. The Ponar samples were taken at a distance of about 1 m from the shore and at a depth of 0.2 m. The sediments were composed of mud laced with cattail (Typha) rhizomes and roots, and stems from the submersed aquatic Myriophyllum. The dominant invertebrates found in the sediments at station 6 were oligochaeta, chrionomidae and ceratopagonidae (Tables 12 and 13).

Tab

le 1

0.

Inve

rteb

rate

dat

a at

sta

tion

5.

Sub

site

5A

S

ubsi

te 5

B

Sub

site

5C

S

ubsi

te 5

D

Tot

al

Org

anis

ms

No.

D

en.

No.

D

en.

No.

D

en.

No.

D

en.

No

Den

.

Am

ph

ipo

da

0 0

2 30

6

133

9 13

3 17

58

B

aso

mm

ato

ph

ora

L

ymna

eida

e 3

27

9 13

3 8

178

4 59

24

82

D

ipte

ra

Chi

rono

mid

ae

73

649

17

252

62

1378

43

63

7 19

5 66

6 C

erat

op

ago

nid

ae

40

356

8 11

9 13

28

9 17

25

2 78

26

7 H

alac

arid

ae

2 18

2

30

0 0

0 0

4 14

H

irud

inae

2

18

0 0

0 0

0 0

2 7

Isop

oda

0 0

4 59

2

44

0 0

6 21

N

emat

od

a 0

0 0

0 4

89

2 30

6

21

Oli

goch

aeta

85

75

6 9

133

330

182

606

2072

73

33

2696

O

stra

coda

0

0 0

0 9

200

18

267

27

92

Tri

chop

tera

1

9 0

0 1

22

0 0

2 7

Tot

al

206

1831

51

75

6 43

5 96

67

275

4074

96

7 33

06

©

~° ~r,

t~

to

Tab

le 1

1.

Ch

iro

no

mid

dat

a at

sta

tio

n 5

Su

bsi

te 5

A

Su

bsi

te 5

B

Su

bsi

te 5

C

Su

bsi

te 5

D

To

tal

Gen

us

N.

D.

N.

D.

N.

D.

N.

D.

No

. %

def

. D

en.

Acr

icot

opus

1

1 0

0 2

0 4

0 8

12.5

27

C

hiro

nom

us

3 1

1 0

12

2 4

0 23

12

79

C

lado

tany

tars

us

0 0

3 0

16

0 0

0 19

0

65

Cri

coto

pus

bici

nctu

s 11

0

0 0

1 0

0 0

12

0 41

C

rico

topu

s is

ocla

dius

28

1

0 0

0 0

9 0

38

2.6

130

Ein

feld

ia

2 0

0 0

0 0

0 0

2 0

7 N

atar

sia

balt

imor

e 9

0 0

0 0

0 0

0 9

0 31

P

arat

anyt

arsu

s 11

1

0 0

0 0

0 0

12

8.3

41

Pro

clad

ius

0 0

0 0

1 0

0 0

1 0

3 P

sect

rocl

adiu

s 0

0 0

0 1

0 6

0 7

0 24

P

sect

rota

nypu

s 2

0 11

0

22

0 17

0

52

0 17

8 T

anyp

us

2 0

0 0

0 0

0 0

2 0

7 T

anyt

arsu

s 0

0 2

0 5

0 3

0 10

0

34

To

tal

69

4 17

0

62

2 43

0

195

Nu

mb

er o

f P

on

ars

5 3

2 3

13

Den

sity

64

9 25

2 13

78

637

667

% d

efo

rmit

y

5.5

0 3.

2 0

3.1

3.1

667

g~


Table 12. Invertebrate data at station 6.

Subsite 6 Organism No. Density

Diptera Chironomidae 107 2378 Ceratopagonidae 8 177

Nematoda 2 44 Oligochaeta 94 2089

Total 211 4689

Station 7

Station 7 was located in Thompson's Creek close to the confluence of the Welland River (Fig. 12). Seven Ponar samples were taken on December 8, 1991 from station 7. On the one side of this creek at this station was pasture land and on the other side was a small, densely wooded area. A dense stand of bushes and small trees was located close to the shore. When we examined this station, we observed a small stream flowing from the wooded area into Thompson's Creek (located approximately 70 m from River Road). To avoid any influence from this small creek, two Ponar samples were taken 10 m upstream from the mouth of this small stream (subsite 7A, Fig. 12). Samples from subsite 7A contained mostly sand and gravel. Five Ponar samples were collected at subsite 7B at the confluence of Thompson's Creek and the Welland River (3 m from the shore, at a depth of 1 m). Sediment from this subsite was composed of hard pink clay with a lot of decomposed leaves and branches.

Chironomid mentum deformity frequency at station 7 was 3.7%. Subsite 7A (closest subsite to the small stream) displayed lower mentum deformities than subsite 7B.

~ pasture area , overall lenght 150 m t

Thomoson's Creek flow a 7B m~ n

f \ fo res t

scale: 1 cm =15m N v

Fig. 12. Sampling locations at stations 6 and 7.



Subsite 6 Total Genus N D No. % def. Density

Clinotanypus 3 1 4 25% 89 Cricotopus isocladius 1 0 1 0 22 Dicrotendipies 1 0 1 0 22 Einfeldia 1 0 1 0 22 Natarsia baltimore 1 0 1 0 22 Polypedilum 79 1 80 1.25% 1778 Procladius 14 1 15 6.7% 333 Psectrotanypus 4 0 4 0 89

Total 104 3 107 2.8 2378 Number of Ponars 2 Chironomid density 2,378 % of deformities 2.8%

Table 14. Invertebrate data at station 7.

Subsite 7A Subsite 7B Total Organism No. Den. No. Den. No. Den.

Diptera Chironomidae 214 4756 137 1218 351 2229 Ceratopagonidae 0 0 4 36 4 25

Oligochaeta 22 489 16 142 38 95

Total 236 5245 157 1396 393 2249

Polypedilum was the most abundant chironomid collected at this station (63.2%) and Procladius was the next most abundant taxon (18.2%).

Discussion

Over 45 million people live in the Great Lakes basin. Increasingly, scientific studies are uncovering evidence of the effects of toxins on fish and wildlife, especially in some heavily polluted areas. Among these effects are high tumour frequencies in some fish species and deformed birds, mammals and invertebrates (Gilbertson et al., 1991). This should not be surprising, however, because it is well known that some of the most dangerous toxins known to man have been released into the Niagra River watershed. Many of these do not break down when consumed by animals. Instead, they concentrate as they move up the food chain.

From a previous study (Dickman et al., 1983; Dickman, 1988) we concluded that chemicals which Cyanamid had discharged to the Welland River were so toxic that virtually all plant and animal life had been eliminated from Thompson's Creek and a section of the Welland River downstream of the confluence of Thompson's Creek


10000 I i [ ] dens~y-chiron.

8000 [ ] dens~y-inved.

6000

c m 4000

2000 -

1 2 3 4 5 6 7 stations

Fig. 13. Density of chironomids and invertebrates at the seven sampling stations.

E "0

u

1 2 3 4 5 6 7 stations

Fig. 14. Percentage of chironomid mentum deformities at each sampling station.

15 .15 [ ] richness [ ] diversity

10 -10

Q Q = _> . c "0

=- 5 -5

0 1 2 3 4 5 6 7

stations

Fig. 15. Chironomid diversity and generic richness at each sampling station.


(Dickman et al., 1990). Some of the chemicals entering the Welland River were cyanide, ammonia, urea, nitrate, phosphorus, chromium, nickel and zinc (MOE, 1987). Cabosil, calcium carbide, hydrogen peroxide, dicyandiamide, acetonitrile neodene 6 monylphe- nol, cyclooctadiene, toluene, isobutylene and triethylpentylphosphine may also have been discharged by Cyanamid (Dickman et al., 1990). By 1990, conditions had improved to the point that some of the more tolerant invertebrates had recolonized Thompson's Creek and a section of the Welland River located near an abandoned Cyanamid pipe (stations 1 and 2). In 1980 the company stopped discharging toxic material to the Welland River from this pipe, due to a court order.

From 1974, when Welland River monitoring by the Brock University toxicology team began, to today, no aquatic plants were to be found near the confluence of Thompson's Creek and the Welland River. We undertook three studies in order to determine why aquatic plants and, until recently (1989), aquatic macroinvertebrates were absent in this section of the Welland River. We concluded that impairments as defined by the International Joint Commission existed at many of the 7 sampling sites. We also attempted to document any changes that had occurred since our study of 1986 (Dickman et al., 1990).

Tables 16-18 summarize our data for all seven study sites. We concluded that the majority of the benthic invertebrate species which occurred at 6 out of 7 of these stations in the Welland River and Thompson's Creek were pollution tolerant taxa. The lone exception was station 5, the upstream 'control' site. The density of sludge worms at site 1 (Fig. 13) was higher than at any other site (68% of all the organisms collected at station 1 were sludge worms). Sludge worm densities ranged from 2,487 m -2 at station 1 to 95 m -2 at station 7. Station 1 was also the only site where oily wastes were observed. Because of the high density of sludge worm (oligochaetes) at station 1, biotic diversity was low and invertebrate density (Fig. 13) was high (over 8,000 m -2, Table 18).

Amphipods and isopods were absent from stations 4, 6 and 7. Because these crustaceans are sensitive to ammonia shock loads (Dickman et al., 1990) and because ammonia shock loads continue to plague Cyanamid's discharges to Thompson's Creek, it was not surprising to find that crustaceans were absent at all downstream stations in Thompson's Creek. Some crustaceans were found at station 5 in Thompson's Creek, which is located upstream of the Cyanamid discharge pipe to Thompson's Creek (Fig. 1).

Station 2 was located immediately downstream of station i at the site of a surface runoff pipe which drains much of the surface flow from the south section of the 1 km long Cyanamid Canada property (Fig. 2). Invertebrate densities at station 2 (2,000 m -2) were lower than at station 1 because there were far fewer sludge worms at station 2.

Chironomids were the second most abundant taxon at the stations that we investi- gated. Polypedilum cf. halterale and Procladius sp. (two pollution tolerant species) were the most common chironomid taxa in the study area. Taxa belonging to the Orthocladi- nae family ( Paraphaenocladius, Cricotopos cf. bicinctus and Cricotopus cf. isocladius) were more common in Thompson's Creek than in the Welland River. Generally, orthocladinae were absent or occurred in relatively low numbers at the 3 Welland River stations (stations 1-3).

A total of 1,275 individual chironomids were collected from the 7 stations and 550 (43%) of them were Polypedilum cf. halterale. Of these, 19% (243 individuals) belonged to the genus Procladius. Stations 3, 6, and 7 had the highest chironomid densities (Fig. 13).

Maximum chironomid deformity frequencies (Fig. 14) occurred at station 2 (7.4%),

The impact o f the Cyanamid Canada Co. discharges to benthic invertebrates


117

Subsite 7A Subsite 7B Total Genus N. D. N. D. No. % def. Density

Clinotanypus 31 5 3 0 39 6.3% 248 Dicrotendipies 1 0 0 0 1 0 6 Natarsia baltimore 1 0 0 0 1 0 6 Parametriocnemus 1 0 0 0 1 0 6 Phaenopsectra 19 1 1 0 21 4.8% 133 Polypedilum halterale 149 1 71 1 222 1.0% 1410 Procladius 5 0 56 4 64 6.3% 406 Tanypus 0 0 1 0 1 0 6

207 7 132 5 Total 214 137 351 3.7% 2229 Number of Ponars 2 5 7 Density 4756 1218 2229 % of deformities 3.3 3.6 3.7

Table 16. Summary information

Station number 1 2 3 4 5 6 7 Number of Ponars 18 19 5 21 13 2 7 Number of chironomids 62 121 179 260 195 107 351 Chironomid density 153 283 1591 550 667 2378 2262 % of deformity 1.6 7.4 1.1 5.0 3.1 2.8 3.7 Invertebrate density 8778 1635 2177 3193 3306 4689 2245

where elevated levels of arsenic, cobalt, molybdenum, nickel, tungsten, and zinc were found in the sediments. Most of the chironomid deformities appeared at subsite 2A (12.9%) located 0.5 m from a Cyanamid storm drain pipe (subsite 2B, 10.4%). The deformity frequency variance at station 2 was high and~ as a result, no significant (p > 0.05) difference between this site and the control site (station 5, 3.1%) was observed. We speculated that teratogenic impacts of contaminated sediments at Cyanamid stations 1 and 2 were not occurring because heavy metal contaminants detected at these stations were ' locked' up 3 -4 cm below the mud-wa te r interface where they were unavailable to the majority of the benthic invertebrates observed at these sites. The absence of clams and mayflies, which burrow to greater depths than do the chironomids and sludge worms, was probably due to the inability of the deeper dwelling burrowers to tolerate the contaminants which we recorded from 3-4 cm below the mud-wa te r interface at stations 1 and 2.

The second highest frequency of chironomid mentum deformities (5.0%) occurred at station 4, where elevated levels of arsenic and molybdenum were found. Both of these subsites were situated close to an active drainage pipe, in contrast to station 1 where the discharge pipe had been abandoned in 1980. The lowest level of mentum deformities (1.1%) occurred at station 3.


I

Z

0

~q o~

o

I

e~ 0

o

0 ° ~

0

[,,.

0 " ~

0 , ' ¢~

Z

~9

Z

o

0

6 z

e .

o


o

e~

°~

tZ

r:9

6 z

~D

ad

"e9

6 z

~D

6 Z

eD

o o ~ o o o ~ o ~ o ~ o o ~ o ~ o ~ ~ o

oo ooooooo o o ooo

0 0 ~ 0 0 0 ~ 0 ~ 0 ~ 0 ~ 0 ~ 0

oo ooooooooo o ooo tt~ eq ~ ,6 rq

o 0 ~ 0 0 ~ ~ 0 0 0 ~ 0 0 0 0


Table 18. Total invertebrate data from seven study locations: Cyanamid, October 1991-February 1992. (a) Stations 1-4.

Station 1 Station 2 Station 3 Station 4

Organisms No. Den. No. Den. No. Den. No. Den.

Amphipoda 8 20 21 49 8 71 0 0 Basommatophora

Lymnaeida 0 0 0 0 0 0 3 6 Coleoptera

Haliplidae 1 3 0 0 0 0 0 0 Hydrophilidae 0 0 0 0 0 0 1 2

Diptera Chironomidae 62 153 121 283 179 1591 260 550 Ceratopagonidae 20 49 13 31 4 36 59 125 Tabanidae 0 0 0 0 0 0 3 6

Ephemeroptera 0 0 3 7 0 0 0 0 Eulamellibranchia 0 0 5 12 0 0 0 0 Gastropoda 1 0 5 12 0 0 0 0 Halacaridae 1 3 0 0 0 0 0 0 Hirudinae 9 22 10 23 2 18 5 11 Isopods 3 7 19 44 8 71 0 0 Odonata 0 0 0 0 0 0 3 6 Oligochaeta 3450 6049 504 1179 43 382 1175 2487 Plecoptera 0 0 3 7 1 9 0 0 Trichoptera 2 5 0 0 0 0 0 0

Total 3556 8780 696 1635 245 2179 1509 3194

Table 18. (Continued). Stations 5-7.

Station 5 Station 6 Station 7

Organisms No. Den. No. Den. No. Den.

Amphipoda 17 58 0 0 0 0 Basommatophora

Lymnaeida 24 82 0 0 0 0 Diptera

Chironomidae 195 667 107 2378 351 2229 Ceratopagonidae 78 2670 8 178 4 26

Hirudinae 2 7 0 0 0 0 Isopods 6 21 0 0 0 0 Nematoda 6 21 2 44 0 0 Oligochaeta 606 2072 94 2089 38 95 Ostracoda 27 92 0 0 0 0 Trichoptera 2 7 0 0 0 0

Total 967 3306 211 4689 393 2246


Chironomid generic richness (Fig. 15) was highest at station 5 which was referred to as 'control' site because it received the smallest amount of discharge water from the Cyanamid site.

Conclusion

The majority of the benthic invertebrates collected from the study area were pollution tolerant taxa (e.g., sludge worms constituted 68% of all of the organisms collected). The lowest chironomid densities were at stations 1, 2, and 4 which were the only stations situated close to the Welland River discharge pipes. In addition, stations 2 and 4 displayed the highest frequency of chironomid mentum deformities. Stations 1 and 2 were located near a pipe which was once one of Cyanamid's major discharge point sources to the Welland River. In 1980 a court order stopped the company from discharging toxic material to the Welland River via the pipe at station 1. Elevated levels of cobalt (10 times above background), molybdenum (6 times above background), nickel (8 times above background), tungsten (284 times above background) and zinc (20 times above background) at stations 1 and 2 were correlated with the presence of pollution tolerant chironomid taxa such as Polypedilum and Procladius. The highest sludge worm densities and the lowest chironomid densities occurred at station 1 (Fig. 13), where oily material was found in the sediment. Because the oily anaerobic sediments at station 1 were free of chironomids below the top few centimetres, we speculated that the contaminants in these sediments were unavailable to the chironomids and, as a result, the chironomid deformity frequencies at station 1 were lower than at station 2 (Fig. 14), where the chironomids were able to contact the contaminants directly.

Among the 1,275 chironomids taken from the seven Cyanamid stations, only 3.6% were deformed. This was not significantly higher than background (control site) deformity frequencies. Maximum chironomid deformity frequencies occurred at station 2 (7.4 %), where elevated levels of arsenic, cobalt, molybdenum, nickel, tungsten, and zinc were found in the sediments. We speculated that teratogenic impacts of contaminated sediments at Cyanamid stations 1 and 2 were not occurring at excessive levels because heavy metal contaminants were locked up 3-4 cm below the mud-water interface where they were unavailable to the majority of the benthic invertebrates observed at these sites. The absence, at stations 1, 2 and 4, of clams and mayflies which burrow to greater depths than do chironomids and sludge worms, probably reflects the inability of the deeper dwelling burrowers to tolerate the contaminants which we recorded at these stations. The absence of all crustaceans from these same 3 stations, when coupled with low biotic diversity and elevated heavy metal concentrations in the sediments taken from these three stations, is reason to consider them as impaired. It was concluded that remedial action at these three stations should be considered, so that they can be delisted by the IJC.

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