카드뮴 및 크롬화합물이 송사리 (Apiochilus latipes)에 미치는 독성에 관한 연구

Abstract

[한글]

최근 급속한 산업발전과 고도성장은 각종 오염물질을 배출하여 그 주변 자연환경을 파괴시키고 나아가 직접, 간접으로 각 생물 및 생태계 자체에 많은 영향을 미치고 있다.

특히 독성 오염물질인 농약과 중금속을 비롯한 유해물질은 자연중에 잔유성이 매우 길며 미량으로도 수중생물에 축척과 농축이 가능하고 먹이연쇄(food chain)를 통해 인간에까지 영향을 미치게된다.

이에 중금속 중 카드뮴(CdCl^^2로 투여)과 크롬(CrO^^3로 투여)을 대상으로 담수어류인 송사리(Apiochilus latipes)에 농도별, 노출시간별 그리고 투여방법에 따른 중금속함량 변화와 반치사농도, 생물축척지수를 구하였다. 본 실험에서 얻어진 결과는 다음과 같다.

1. 카드뮴(CdCl^^2로 투여)의 24 hr-LC^^50의 값은 0.317 mg/ℓ 이며 크롬(CrO^^3로 투여)의 24 hr-LC^^50의 값은 3.83 mg/ℓ 이었다.

2. 카드뮴 (CdCl^^2로 투여)과 크롬(CrO^^3 로 투여)을 24 hr-LC^^40 농도(카드뮴- 0.3mg/ℓ, 크롬- 3.8 mg/ℓ)로 24시간 혼합투여 하였을 경우 단독투여 했을 경우와 비교한 결과, 카드뮴화합물(CdCl^^2)의 경우만 혼합투여 했을 때의 함량이 높게 나타났으며 각기 단독투여 했을 때와 혼합 투여했을 때의 축척농도의 차이가 (t = -2.38, P< 0.05)있게 나타났다.

3. 카드뮴 (CdCl^^2로 투여 )을 LC^^50의 1/5농도(0.064mg/ℓ)와 1/10농도(0.032mg/ℓ) 로 1일, 4일 및 7일 동안 노출시켜 송사리에 축척한 카드뮴의 생물축척지수(BCF)를 구하여본 결과 카드뮴농도(P, mg/ℓ)및 노출시간(T, day)과의 상관된 식을 구하였다.

log BCF= 0.681 log P·T + 1.62 (r**2 = 0.805)

P : pollutant concentration (mg/ℓ)

T : exposure time (day)

4. 크롬( CrO^^3로 투여)을 LC^^50의 1/5농도(0.75mg/ℓ)와 1/10농도(0.38mg/ℓ)로 1일, 4일 및 7일 동안 노출시켜 송사리에 축척된 크롬의 생물축척지수(BCF)를 구하여본 결과 크롬농도(P, mg/ℓ)및 노출시간(T, day)과의 상관된 식을 구하였다.

log BCF = 0.984 log P·T + 0.330 (r**2 =0.726)

P : pollutant concentration (mg/ℓ)

T : exposure time (day)

상기한 실험적 조건하에서 카드뮴화합물(CdCl^^2)과 크롬화합물(CrO^^3)의 농도에 따라 송사리체내 중금속함량의 변화가 있었으며 농도증가에 따라 체내 중금속함량이 증가했다.

[영문]

In order to investigate acute toxicity and bioconcentration of heavy metals for a freshwater fish, this study was performed in a laboratory.

The fish used in his experiment was killifish, Apiochilus latipes, which is widely distributed In the clean water body such as ponds, lakes, streams and rice paddy fields.

Each ten killifish was accommodated in a water tank and was treated with different concentration of Cd and Cr compound. The 24 hour LC^^50 was obtained by plotting on the log-normal distribution graph.

The combined effect of Cd and Cr compound was also investigated: the fish was treated with Cd or Cr compound only, and Cd and Cr compound together, respectively.

The bioconcentration factor (BCF) was determined by measuring a ratio between the Cd and Cr compound concentrations in the fish and those In water for 7 days with various Sublethal concentrations.

The results were summarized as follows :

1. The 24 hour-LC^^50 's of Cd and Cr were 0.317 mg/ℓ and 3.83 mg/ℓ, respectively.

2. When single or/and combined treatment with Cd (0.3mg/ℓ) or/and Cr(3.8mg/ℓ) to Apiochilus latipes for 24 hours were performed, there was no difference between the single and the combined treatment in bioaccoumulated concentrations.

3.When Apiochilus latipes was exposed to 0.064mg'ℓ (1/5 of 24hr-LC^^50) and 0.032mg/ℓ (1/10 of LC^^50) of Cd f7r seven days, the bioconcentration factors (BCF) were 20.62 and 25.93, respectively. The BCF of Cd was obtained as a linearity according to the concentration and exposure time as follows :

log BCF = 0.681 log P·T + 1.62 (r**2=0.805)

where, P : pollutant concentration (mg/ℓ)

T : exposure time (day)

4. When Apiochilus latipes was exposed to 0.75mg/ℓ (1/5 of 24hr-LC^^50) and 0.38 mg/ℓ (1/10 of 24hr-LC^^50) of Cr for seven days, the bioconcentration factors (BCF) were 8.62 and 10.63, respectively. The BCF of Cr was shown as a linearity according to the concentration and exposure time.

log BCF = 0.984 log P·T + 0.330 (r**2=0.726)

where, P: pollutant concentration (mg/ℓ)

T : exposure tome (day)